8XC196MC, 8XC196MD,
8XC196MH Microcontroller
User’s Manual
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8XC196MC,
8XC196MD, 8XC196MH
Microcontroller
User’s Manual
August 2004
Order Number 272181-003
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CONTENTS
CHAPTER 1
GUIDE TO THIS MANUAL
1.1
1.2
1.3
1.4
MANUAL CONTENTS................................................................................................... 1-1
NOTATIONAL CONVENTIONS AND TERMINOLOGY ................................................ 1-3
RELATED DOCUMENTS .............................................................................................. 1-5
ELECTRONIC SUPPORT SYSTEMS........................................................................... 1-8
World Wide Web .....................................................................................................1-11
TECHNICAL SUPPORT .............................................................................................. 1-11
PRODUCT LITERATURE............................................................................................ 1-11
1.4.4
1.5
1.6
CHAPTER 2
ARCHITECTURAL OVERVIEW
2.1
2.2
2.3
2.3.1
2.3.2
2.3.3
TYPICAL APPLICATIONS............................................................................................. 2-1
MICROCONTROLLER FEATURES.............................................................................. 2-1
FUNCTIONAL OVERVIEW............................................................................................ 2-2
CPU Control ..............................................................................................................2-4
Register File ..............................................................................................................2-4
Register Arithmetic-logic Unit (RALU) .......................................................................2-4
2.3.3.1
2.3.3.2
2.3.4
2.3.5
Code Execution ....................................................................................................2-5
Instruction Format ................................................................................................2-5
Memory Interface Unit ...............................................................................................2-6
Interrupt Service ........................................................................................................2-6
2.4
2.5
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.5.6
2.5.7
2.5.8
INTERNAL TIMING........................................................................................................ 2-7
INTERNAL PERIPHERALS........................................................................................... 2-8
I/O Ports ....................................................................................................................2-9
Serial I/O (SIO) Port ..................................................................................................2-9
Event Processor Array (EPA) and Timer/Counters .................................................2-10
Pulse-width Modulator (PWM) ................................................................................2-10
Frequency Generator ..............................................................................................2-10
Waveform Generator ..............................................................................................2-10
Analog-to-digital Converter .....................................................................................2-11
Watchdog Timer ......................................................................................................2-11
SPECIAL OPERATING MODES ................................................................................. 2-11
Reducing Power Consumption ...............................................................................2-11
Testing the Printed Circuit Board ............................................................................2-11
Programming the Nonvolatile Memory ....................................................................2-12
2.6
2.6.1
2.6.2
2.6.3
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8XC196MC, MD, MH USER’S MANUAL
CHAPTER 3
PROGRAMMING CONSIDERATIONS
3.1
3.1.1
OVERVIEW OF THE INSTRUCTION SET.................................................................... 3-1
BIT Operands ............................................................................................................3-2
BYTE Operands ........................................................................................................3-2
SHORT-INTEGER Operands ....................................................................................3-2
WORD Operands ......................................................................................................3-2
INTEGER Operands .................................................................................................3-3
DOUBLE-WORD Operands ......................................................................................3-3
LONG-INTEGER Operands ......................................................................................3-4
Converting Operands ................................................................................................3-4
Conditional Jumps ....................................................................................................3-4
3.1.2
3.1.3
3.1.4
3.1.5
3.1.6
3.1.7
3.1.8
3.1.9
3.1.10 Floating Point Operations .........................................................................................3-4
3.2
ADDRESSING MODES................................................................................................. 3-5
Direct Addressing ......................................................................................................3-6
Immediate Addressing ..............................................................................................3-6
Indirect Addressing ...................................................................................................3-6
3.2.1
3.2.2
3.2.3
3.2.3.1
3.2.3.2
3.2.4
3.2.4.1
3.2.4.2
3.2.4.3
Indirect Addressing with Autoincrement ...............................................................3-7
Indirect Addressing with the Stack Pointer ...........................................................3-7
Indexed Addressing ..................................................................................................3-7
Short-indexed Addressing ....................................................................................3-7
Long-indexed Addressing ....................................................................................3-8
Zero-indexed Addressing .....................................................................................3-8
3.3
3.3.1
3.3.2
3.4
3.4.1
3.4.2
3.4.3
ASSEMBLY LANGUAGE ADDRESSING MODE SELECTIONS.................................. 3-9
Direct Addressing ......................................................................................................3-9
Indexed Addressing ..................................................................................................3-9
SOFTWARE STANDARDS AND CONVENTIONS ....................................................... 3-9
Using Registers .........................................................................................................3-9
Addressing 32-bit Operands ...................................................................................3-10
Linking Subroutines ................................................................................................3-10
SOFTWARE PROTECTION FEATURES AND GUIDELINES .................................... 3-11
3.5
CHAPTER 4
MEMORY PARTITIONS
4.1
4.1.1
4.1.2
4.1.3
4.1.4
MEMORY PARTITIONS ................................................................................................ 4-1
External Devices (Memory or I/O) .............................................................................4-1
Program and Special-purpose Memory ....................................................................4-1
Program Memory ......................................................................................................4-2
Special-purpose Memory ..........................................................................................4-3
Reserved Memory Locations ...............................................................................4-3
Interrupt and PTS Vectors ....................................................................................4-3
Security Key .........................................................................................................4-4
Chip Configuration Bytes (CCBs) .........................................................................4-4
Special-function Registers (SFRs) ............................................................................4-4
4.1.4.1
4.1.4.2
4.1.4.3
4.1.4.4
4.1.5
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CONTENTS
4.1.5.1
4.1.5.2
4.1.6
4.1.6.1
4.1.6.2
4.1.6.3
Memory-mapped SFRs ........................................................................................4-5
Peripheral SFRs ...................................................................................................4-5
Register File ..............................................................................................................4-9
General-purpose Register RAM .........................................................................4-10
Stack Pointer (SP) ..............................................................................................4-10
CPU Special-function Registers (SFRs) .............................................................4-11
4.2
4.2.1
4.2.2
4.2.2.1
4.2.2.2
WINDOWING............................................................................................................... 4-12
Selecting a Window ................................................................................................4-13
Addressing a Location Through a Window .............................................................4-14
32-byte Windowing Example ..............................................................................4-16
64-byte Windowing Example ..............................................................................4-16
128-byte Windowing Example ............................................................................4-16
Unsupported Locations Windowing Example .....................................................4-16
Using the Linker Locator to Set Up a Window ....................................................4-17
Windowing and Addressing Modes .........................................................................4-19
4.2.2.3
4.2.2.4
4.2.2.5
4.2.3
CHAPTER 5
STANDARD AND PTS INTERRUPTS
5.1
5.2
5.3
5.3.1
5.3.1.1
5.3.1.2
5.3.1.3
5.3.2
OVERVIEW OF INTERRUPTS...................................................................................... 5-1
INTERRUPT SIGNALS AND REGISTERS ................................................................... 5-3
INTERRUPT SOURCES AND PRIORITIES.................................................................. 5-4
Special Interrupts ......................................................................................................5-6
Unimplemented Opcode ......................................................................................5-6
Software Trap .......................................................................................................5-6
NMI .......................................................................................................................5-6
External Interrupt Pin ................................................................................................5-6
Multiplexed Interrupt Sources ...................................................................................5-7
End-of-PTS Interrupts ...............................................................................................5-9
5.3.3
5.3.4
5.4
5.4.1
5.4.2
INTERRUPT LATENCY................................................................................................. 5-9
Situations that Increase Interrupt Latency ................................................................5-9
Calculating Latency .................................................................................................5-10
5.4.2.1
5.4.2.2
5.5
5.5.1
5.5.2
Standard Interrupt Latency .................................................................................5-10
PTS Interrupt Latency ........................................................................................5-11
PROGRAMMING THE INTERRUPTS......................................................................... 5-12
Modifying Interrupt Priorities ...................................................................................5-18
Determining the Source of an Interrupt ...................................................................5-20
INITIALIZING THE PTS CONTROL BLOCKS............................................................. 5-24
Specifying the PTS Count .......................................................................................5-25
Selecting the PTS Mode .........................................................................................5-27
Single Transfer Mode ..............................................................................................5-27
Block Transfer Mode ...............................................................................................5-30
A/D Scan Mode .......................................................................................................5-32
5.6
5.6.1
5.6.2
5.6.3
5.6.4
5.6.5
5.6.5.1
5.6.5.2
5.6.5.3
A/D Scan Mode Cycles ......................................................................................5-35
A/D Scan Mode Example 1 ................................................................................5-35
A/D Scan Mode Example 2 ................................................................................5-37
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5.6.6
5.6.6.1
5.6.6.2
5.6.6.3
5.6.6.4
Serial I/O Modes .....................................................................................................5-37
Synchronous SIO Transmit Mode Example .......................................................5-43
Synchronous SIO Receive Mode Example ........................................................5-47
Asynchronous SIO Transmit Mode Example .....................................................5-50
Asynchronous SIO Receive Mode Example ......................................................5-55
CHAPTER 6
I/O PORTS
6.1
6.2
6.2.1
6.2.2
6.3
6.3.1
6.3.2
6.3.3
6.3.4
I/O PORTS OVERVIEW ................................................................................................ 6-1
INPUT-ONLY PORTS 1 (MC, MD ONLY) AND 0.......................................................... 6-2
Standard Input-only Port Operation ..........................................................................6-3
Standard Input-only Port Considerations ..................................................................6-4
BIDIRECTIONAL PORTS 1 (MH ONLY), 2, 5, AND 7 (MD ONLY)............................... 6-4
Bidirectional Port Operation ......................................................................................6-6
Bidirectional Port Pin Configurations .........................................................................6-9
Bidirectional Port Pin Configuration Example .........................................................6-11
Bidirectional Port Considerations ............................................................................6-12
BIDIRECTIONAL PORTS 3 AND 4 (ADDRESS/DATA BUS)...................................... 6-14
Bidirectional Ports 3 and 4 (Address/Data Bus) Operation .....................................6-15
Using Ports 3 and 4 as I/O ......................................................................................6-16
Design Considerations for Ports 3 and 4 ................................................................6-16
STANDARD OUTPUT-ONLY PORT 6 ....................................................................... 6-16
Output-only Port Operation .....................................................................................6-17
Configuring Output-only Port Pins ..........................................................................6-17
6.4
6.4.1
6.4.2
6.4.3
6.5
6.5.1
6.5.2
CHAPTER 7
SERIAL I/O (SIO) PORT
7.1
7.2
7.3
7.3.1
7.3.1.1
7.3.1.2
7.3.2
7.3.2.1
SERIAL I/O (SIO) PORT FUNCTIONAL OVERVIEW ................................................... 7-1
SERIAL I/O PORT SIGNALS AND REGISTERS .......................................................... 7-2
SERIAL PORT MODES................................................................................................. 7-4
Synchronous Modes (Modes 0 and 4) ......................................................................7-5
Mode 0 .................................................................................................................7-5
Mode 4 .................................................................................................................7-6
Asynchronous Modes (Modes 1, 2, and 3) ...............................................................7-7
Mode 1 .................................................................................................................7-7
Mode 2 .................................................................................................................7-8
Mode 3 .................................................................................................................7-9
Mode 2 and 3 Timings ..........................................................................................7-9
Multiprocessor Communications ..........................................................................7-9
7.3.2.2
7.3.2.3
7.3.2.4
7.3.2.5
7.4
7.4.1
7.4.2
7.4.3
7.4.4
PROGRAMMING THE SERIAL PORT........................................................................ 7-10
Configuring the Serial Port Pins ..............................................................................7-10
Programming the Control Register ..........................................................................7-10
Programming the Baud Rate and Clock Source .....................................................7-12
Enabling the Serial Port Interrupts ..........................................................................7-14
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CONTENTS
7.4.5
Determining Serial Port Status ................................................................................7-15
CHAPTER 8
FREQUENCY GENERATOR
8.1
8.2
8.2.1
8.2.2
8.2.3
FUNCTIONAL OVERVIEW............................................................................................ 8-1
PROGRAMMING THE FREQUENCY GENERATOR ................................................... 8-3
Configuring the Output ..............................................................................................8-3
Programming the Frequency ....................................................................................8-3
Determining the Current Value of the Down-counter ................................................8-4
APPLICATION EXAMPLE............................................................................................. 8-4
8.3
CHAPTER 9
WAVEFORM GENERATOR
9.1
9.2
9.3
WAVEFORM GENERATOR FUNCTIONAL OVERVIEW.............................................. 9-1
WAVEFORM GENERATOR SIGNALS AND REGISTERS........................................... 9-3
WAVEFORM GENERATOR OPERATION.................................................................... 9-4
Timebase Generator .................................................................................................9-4
Phase Driver Channels .............................................................................................9-5
Control and Protection Circuitry ................................................................................9-5
Register Buffering and Synchronization ....................................................................9-6
Operating Modes ......................................................................................................9-7
9.3.1
9.3.2
9.3.3
9.3.4
9.3.5
9.3.5.1
9.3.5.2
9.4
9.4.1
9.4.2
9.4.3
9.4.4
Center-aligned Modes ..........................................................................................9-9
Edge-Aligned Modes ..........................................................................................9-10
PROGRAMMING THE WAVEFORM GENERATOR................................................... 9-12
Configuring the Outputs ..........................................................................................9-12
Controlling the Protection Circuitry and EXTINT Interrupt Generation ....................9-15
Specifying the Carrier Period and Duty Cycle .........................................................9-16
Specifying the Operating Mode and Dead Time and Starting the Counter .............9-17
DETERMINING THE WAVEFORM GENERATOR’S STATUS ................................... 9-19
ENABLING THE WAVEFORM GENERATOR INTERRUPTS..................................... 9-19
DESIGN CONSIDERATIONS...................................................................................... 9-20
Dead Time and Duty Cycle .....................................................................................9-20
EXTINT Interrupts and Protection Circuitry .............................................................9-21
PROGRAMMING EXAMPLE....................................................................................... 9-21
9.5
9.6
9.7
9.7.1
9.7.2
9.8
CHAPTER 10
PULSE-WIDTH MODULATOR
10.1 PWM FUNCTIONAL OVERVIEW................................................................................ 10-1
10.2 PWM SIGNALS AND REGISTERS ............................................................................. 10-2
10.3 PWM OPERATION...................................................................................................... 10-3
10.4 PROGRAMMING THE FREQUENCY AND PERIOD.................................................. 10-4
10.5 PROGRAMMING THE DUTY CYCLE......................................................................... 10-6
10.5.1 Sample Calculations ...............................................................................................10-7
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10.5.2 Reading the Current Value of the Down-counter ....................................................10-7
10.5.3 Enabling the PWM Outputs .....................................................................................10-8
10.5.4 Generating Analog Outputs ..................................................................................10-10
CHAPTER 11
EVENT PROCESSOR ARRAY (EPA)
11.1 EPA FUNCTIONAL OVERVIEW ................................................................................. 11-1
11.2 EPA AND TIMER/COUNTER SIGNALS AND REGISTERS....................................... 11-2
11.3 TIMER/COUNTER FUNCTIONAL OVERVIEW........................................................... 11-5
11.3.1 Cascade Mode (Timer 2 Only) ................................................................................11-7
11.3.2 Quadrature Clocking Modes ...................................................................................11-7
11.4 EPA CHANNEL FUNCTIONAL OVERVIEW............................................................... 11-9
11.4.1 Operating in Capture Mode ...................................................................................11-10
11.4.1.1 EPA Overruns ..................................................................................................11-12
11.4.1.2 Preventing EPA Overruns ................................................................................11-13
11.4.2 Operating in Compare Mode .................................................................................11-13
11.4.2.1 Generating a Low-speed PWM Output ............................................................11-13
11.4.2.2 Generating the Highest-speed PWM Output ....................................................11-14
11.5 PROGRAMMING THE EPA AND TIMER/COUNTERS............................................. 11-15
11.5.1 Configuring the EPA and Timer/Counter Signals ..................................................11-15
11.5.2 Programming the Timers .......................................................................................11-15
11.5.3 Programming the Capture/Compare Channels .....................................................11-18
11.5.4 Programming the Compare-only Channels ...........................................................11-22
11.6 ENABLING THE EPA INTERRUPTS ........................................................................ 11-23
11.7 DETERMINING EVENT STATUS.............................................................................. 11-24
CHAPTER 12
ANALOG-TO-DIGITAL (A/D) CONVERTER
12.1 A/D CONVERTER FUNCTIONAL OVERVIEW........................................................... 12-1
12.2 A/D CONVERTER SIGNALS AND REGISTERS ........................................................ 12-2
12.3 A/D CONVERTER OPERATION ................................................................................. 12-3
12.4 PROGRAMMING THE A/D CONVERTER.................................................................. 12-4
12.4.1 Programming the A/D Test Register .......................................................................12-5
12.4.2 Programming the A/D Result Register (for Threshold Detection Only) ...................12-5
12.4.3 Programming the A/D Time Register ......................................................................12-6
12.4.4 Programming the A/D Command Register ..............................................................12-7
12.4.5 Enabling the A/D Interrupt .......................................................................................12-8
12.5 DETERMINING A/D STATUS AND CONVERSION RESULTS.................................. 12-9
12.6 DESIGN CONSIDERATIONS.................................................................................... 12-10
12.6.1 Designing External Interface Circuitry ...................................................................12-10
12.6.1.1 Minimizing the Effect of High Input Source Resistance ....................................12-11
12.6.1.2 Suggested A/D Input Circuit .............................................................................12-12
12.6.1.3 Analog Ground and Reference Voltages .........................................................12-12
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CONTENTS
12.6.1.4 Using Mixed Analog and Digital Inputs ............................................................12-13
12.6.2 Understanding A/D Conversion Errors ..................................................................12-13
CHAPTER 13
MINIMUM HARDWARE CONSIDERATIONS
13.1 MINIMUM CONNECTIONS ......................................................................................... 13-1
13.1.1 Unused Inputs .........................................................................................................13-2
13.1.2 I/O Port Pin Connections ........................................................................................13-2
13.2 APPLYING AND REMOVING POWER....................................................................... 13-4
13.3 NOISE PROTECTION TIPS........................................................................................ 13-4
13.4 THE ON-CHIP OSCILLATOR CIRCUITRY ................................................................. 13-5
13.5 USING AN EXTERNAL CLOCK SOURCE.................................................................. 13-7
13.6 RESETTING THE DEVICE.......................................................................................... 13-8
13.6.1 Generating an External Reset ...............................................................................13-10
13.6.2 Issuing the Reset (RST) Instruction ......................................................................13-12
13.6.3 Issuing an Illegal IDLPD Key Operand .................................................................13-12
13.6.4 Generating Wait States .........................................................................................13-12
13.6.5 Enabling the Watchdog Timer ...............................................................................13-12
CHAPTER 14
SPECIAL OPERATING MODES
14.1 SPECIAL OPERATING MODE SIGNALS AND REGISTERS..................................... 14-1
14.2 REDUCING POWER CONSUMPTION ....................................................................... 14-3
14.3 IDLE MODE................................................................................................................. 14-4
14.4 POWERDOWN MODE................................................................................................ 14-5
14.4.1 Enabling and Disabling Powerdown Mode ..............................................................14-5
14.4.2 Entering Powerdown Mode .....................................................................................14-6
14.4.3 Exiting Powerdown Mode .......................................................................................14-6
14.4.3.1 Driving the V Pin Low ......................................................................................14-6
pp
14.4.3.2 Generating a Hardware Reset ...........................................................................14-6
14.4.3.3 Asserting the External Interrupt Signal ...............................................................14-7
14.4.3.4 Selecting R and C ...........................................................................................14-8
1
1
14.5 ONCE MODE............................................................................................................. 14-10
14.6 RESERVED TEST MODES....................................................................................... 14-11
CHAPTER 15
INTERFACING WITH EXTERNAL MEMORY
15.1 EXTERNAL MEMORY INTERFACE SIGNALS AND REGISTERS ............................ 15-1
15.2 CHIP CONFIGURATION REGISTERS AND CHIP CONFIGURATION BYTES ......... 15-5
15.3 BUS WIDTH AND MULTIPLEXING........................................................................... 15-10
15.3.1 Timing Requirements for BUSWIDTH ...................................................................15-13
15.3.2 16-bit Bus Timings ................................................................................................15-14
15.3.3 8-bit Bus Timings ..................................................................................................15-16
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15.4 WAIT STATES (READY CONTROL)......................................................................... 15-17
15.5 BUS-CONTROL MODES........................................................................................... 15-21
15.5.1 Standard Bus-control Mode ..................................................................................15-22
15.5.2 Write Strobe Mode ................................................................................................15-25
15.5.3 Address Valid Strobe Mode ..................................................................................15-27
15.5.4 Address Valid with Write Strobe Mode ..................................................................15-30
15.6 SYSTEM BUS AC TIMING SPECIFICATIONS......................................................... 15-31
15.6.1 Explanation of AC Symbols ..................................................................................15-33
15.6.2 AC Timing Definitions ...........................................................................................15-33
CHAPTER 16
PROGRAMMING THE NONVOLATILE MEMORY
16.1 PROGRAMMING METHODS...................................................................................... 16-1
16.2 OTPROM MEMORY MAP........................................................................................... 16-2
16.3 SECURITY FEATURES............................................................................................... 16-3
16.3.1 Controlling Access to Internal Memory ...................................................................16-3
16.3.1.1 Controlling Access to the OTPROM During Normal Operation ..........................16-4
16.3.1.2 Controlling Access to the OTPROM During Programming Modes .....................16-4
16.3.2 Controlling Fetches from External Memory .............................................................16-6
16.4 PROGRAMMING PULSE WIDTH ............................................................................... 16-8
16.5 MODIFIED QUICK-PULSE ALGORITHM.................................................................... 16-9
16.6 PROGRAMMING MODE PINS.................................................................................. 16-11
16.7 ENTERING PROGRAMMING MODES..................................................................... 16-13
16.7.1 Selecting the Programming Mode .........................................................................16-13
16.7.2 Power-up and Power-down Sequences ................................................................16-14
16.7.2.1 Power-up Sequence .........................................................................................16-14
16.7.2.2 Power-down Sequence ....................................................................................16-14
16.8 SLAVE PROGRAMMING MODE............................................................................... 16-15
16.8.1 Reading the Signature Word and Programming Voltages ....................................16-15
16.8.2 Slave Programming Circuit and Memory Map ......................................................16-16
16.8.3 Operating Environment .........................................................................................16-17
16.8.4 Slave Programming Routines ...............................................................................16-19
16.8.5 Timing Mnemonics ................................................................................................16-24
16.9 AUTO PROGRAMMING MODE ................................................................................ 16-25
16.9.1 Auto Programming Circuit and Memory Map ........................................................16-25
16.9.2 Operating Environment .........................................................................................16-27
16.9.3 Auto Programming Routine ...................................................................................16-27
16.9.4 Auto Programming Procedure ..............................................................................16-29
16.9.5 ROM-dump Mode .................................................................................................16-30
16.10 PCCB AND UPROM PROGRAMMING (8XC196MH ONLY) .................................... 16-30
16.11 RUN-TIME PROGRAMMING .................................................................................... 16-32
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CONTENTS
APPENDIX A
INSTRUCTION SET REFERENCE
APPENDIX B
SIGNAL DESCRIPTIONS
B.1
B.2
B.3
B.4
SIGNAL NAME CHANGES........................................................................................... B-1
FUNCTIONAL GROUPINGS OF SIGNALS ................................................................. B-1
SIGNAL DESCRIPTIONS........................................................................................... B-12
DEFAULT CONDITIONS............................................................................................ B-22
APPENDIX C
REGISTERS
GLOSSARY
INDEX
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8XC196MC, MD, MH USER’S MANUAL
FIGURES
Figure
Page
8XC196Mx Block Diagram ...........................................................................................2-3
2-1
2-2
2-3
2-4
4-1
4-2
4-3
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
5-11
5-12
5-13
5-14
5-15
5-16
5-17
5-18
5-19
5-20
5-21
5-22
5-23
5-24
5-25
5-26
5-27
5-28
6-1
Block Diagram of the Core ...........................................................................................2-3
Clock Circuitry ..............................................................................................................2-7
Internal Clock Phases ..................................................................................................2-8
Register File Memory Map ...........................................................................................4-9
Windowing..................................................................................................................4-12
Window Selection (WSR) Register.............................................................................4-13
Flow Diagram for PTS and Standard Interrupts ...........................................................5-2
Waveform Generator Protection Circuitry.....................................................................5-7
Flow Diagram for the OVRTM Interrupt........................................................................5-8
Standard Interrupt Response Time ............................................................................5-11
PTS Interrupt Response Time....................................................................................5-11
PTS Select (PTSSEL) Register..................................................................................5-14
Interrupt Mask (INT_MASK) Register.........................................................................5-15
Interrupt Mask 1 (INT_MASK1) Register....................................................................5-16
Peripheral Interrupt Mask (PI_MASK) Register..........................................................5-17
Interrupt Pending (INT_PEND) Register ....................................................................5-21
Interrupt Pending 1 (INT_PEND1) Register ...............................................................5-22
Peripheral Interrupt Pending (PI_PEND) Register .....................................................5-23
PTS Control Blocks ....................................................................................................5-25
PTS Service (PTSSRV) Register ...............................................................................5-26
PTS Mode Selection Bits (PTSCON Bits 7:5) ............................................................5-27
PTS Control Block — Single Transfer Mode..............................................................5-28
PTS Control Block — Block Transfer Mode ...............................................................5-31
PTS Control Block – A/D Scan Mode.........................................................................5-33
PTS Control Block 1 – Serial I/O Mode......................................................................5-38
PTS Control Block 2 – Serial I/O Mode......................................................................5-41
Synchronous SIO Transmit Mode Timing...................................................................5-43
Synchronous SIO Transmit Mode — End-of-PTS Interrupt Routine Flowchart..........5-46
Synchronous SIO Receive Timing..............................................................................5-47
Synchronous SIO Receive Mode — End-of-PTS Interrupt Routine Flowchart...........5-50
Asynchronous SIO Transmit Timing...........................................................................5-51
Asynchronous SIO Transmit Mode — End-of-PTS Interrupt Routine Flowchart........5-54
Asynchronous SIO Receive Timing............................................................................5-55
Asynchronous SIO Receive Mode — End-of-PTS Interrupt Routine Flowchart.........5-58
Standard Input-only Port Structure...............................................................................6-3
Bidirectional Port Structure...........................................................................................6-8
Address/Data Bus (Ports 3 and 4) Structure..............................................................6-15
Output-only Port .........................................................................................................6-18
Port 6 Output Configuration (WG_OUTPUT) Register...............................................6-18
SIO Block Diagram.......................................................................................................7-1
Typical Shift Register Circuit for Mode 0 ......................................................................7-5
Mode 0 Timing..............................................................................................................7-6
Serial Port Frames for Mode 1 .....................................................................................7-8
6-2
6-3
6-4
6-5
7-1
7-2
7-3
7-4
xii
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FIGURES
Figure
7-5
7-6
7-7
7-8
8-1
8-2
8-3
8-4
8-5
9-1
9-2
9-3
9-4
9-5
9-6
9-7
Serial Port Frames in Mode 2 and 3.............................................................................7-9
Serial Port Control (SPx_CON) Register....................................................................7-10
Serial Port x Baud Rate (SPx_BAUD) Register.........................................................7-12
Serial Port Status (SPx_STATUS) Register...............................................................7-15
Frequency Generator Block Diagram...........................................................................8-1
Frequency (FREQ_GEN) Register...............................................................................8-3
Frequency Generator Count (FREQ_CNT) Register....................................................8-4
Infrared Remote Control Application Block Diagram....................................................8-5
Data Encoding Example...............................................................................................8-5
Waveform Generator Block Diagram............................................................................9-2
Dead-time Generator Circuitry......................................................................................9-5
Protection Circuitry.......................................................................................................9-6
Center-aligned Modes — Counter Operation...............................................................9-9
Center-aligned Modes — Output Operation...............................................................9-10
Edge-aligned Modes — Counter Operation ...............................................................9-11
Edge-aligned Modes — Output Operation .................................................................9-11
WG Output Configuration (WG_OUTPUT) Register ..................................................9-13
Waveform Generator Protection (WG_PROTECT) Register......................................9-15
Waveform Generator Reload (WG_RELOAD) Register.............................................9-16
Phase Compare (WG_COMPx) Register...................................................................9-17
Waveform Generator Control (WG_CONTROL) Register..........................................9-18
Waveform Generator Counter (WG_COUNTER) Register ........................................9-19
Effect of Dead Time on Duty Cycle ............................................................................9-20
PWM Block Diagram ..................................................................................................10-2
PWM Output Waveforms............................................................................................10-4
PWM Period (PWM_PERIOD) Register.....................................................................10-6
PWM Control (PWMx_CONTROL) Register ..............................................................10-7
PWM Count (PWM_COUNT) Register.......................................................................10-8
Waveform Generator Output Configuration (WG_OUTPUT) Register.......................10-9
D/A Buffer Block Diagram.........................................................................................10-10
PWM to Analog Conversion Circuitry .......................................................................10-10
EPA Block Diagram....................................................................................................11-2
EPA Timer/Counters ..................................................................................................11-6
Quadrature Mode Interface ........................................................................................11-8
Quadrature Mode Timing and Count..........................................................................11-9
A Single EPA Capture/Compare Channel................................................................11-10
EPA Simplified Input-capture Structure....................................................................11-11
Valid EPA Input Events ............................................................................................11-11
Timer 1 Control (T1CONTROL) Register .................................................................11-16
Timer 2 Control (T2CONTROL) Register .................................................................11-17
9-8
9-9
9-10
9-11
9-12
9-13
9-14
10-1
10-2
10-3
10-4
10-5
10-6
10-7
10-8
11-1
11-2
11-3
11-4
11-5
11-6
11-7
11-8
11-9
11-10 EPA Control (EPAx_CON) Registers .......................................................................11-19
11-11 EPA Compare Control (COMPx_CON) Registers....................................................11-22
12-1
12-2
A/D Converter Block Diagram ....................................................................................12-1
A/D Test (AD_TEST) Register....................................................................................12-5
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FIGURES
Figure
Page
A/D Result (AD_RESULT) Register — Write Format.................................................12-6
12-3
12-4
12-5
12-6
12-7
12-8
12-9
A/D Time (AD_TIME) Register ...................................................................................12-7
A/D Command (AD_COMMAND) Register ................................................................12-8
A/D Result (AD_RESULT) Register — Read Format.................................................12-9
Idealized A/D Sampling Circuitry..............................................................................12-10
Suggested A/D Input Circuit .....................................................................................12-12
Ideal A/D Conversion Characteristic.........................................................................12-15
12-10 Actual and Ideal A/D Conversion Characteristics.....................................................12-16
12-11 Terminal-based A/D Conversion Characteristic .......................................................12-18
13-1
13-2
13-3
13-4
13-5
13-6
13-7
13-8
13-9
Minimum Hardware Connections ...............................................................................13-3
Power and Return Connections .................................................................................13-4
On-chip Oscillator Circuit............................................................................................13-5
External Crystal Connections.....................................................................................13-6
External Clock Connections .......................................................................................13-7
External Clock Drive Waveforms................................................................................13-7
Reset Timing Sequence.............................................................................................13-8
General Configuration Register (GEN_CON)............................................................13-9
Internal Reset Circuitry.............................................................................................13-10
13-10 Minimum Reset Circuit .............................................................................................13-11
13-11 Example of a System Reset Circuit..........................................................................13-11
14-1
14-2
14-3
14-4
15-1
15-2
15-3
15-4
15-5
15-6
15-7
15-8
15-9
Clock Control During Power-saving Modes................................................................14-4
Power-up and Power-down Sequence When Using an External Interrupt.................14-7
External RC Circuit.....................................................................................................14-8
Typical Voltage on the VPP Pin While Exiting Powerdown.........................................14-9
Chip Configuration 0 (CCR0) Register .......................................................................15-7
Chip Configuration 1 (CCR1) Register .......................................................................15-9
Multiplexing and Bus Width Options.........................................................................15-11
BUSWIDTH Timing Diagram (8XC196MC, MD) ......................................................15-12
BUSWIDTH Timing Diagram (8XC196MH)..............................................................15-12
Timings for 16-bit Buses...........................................................................................15-15
Timings for 8-bit Buses.............................................................................................15-17
READY Timing Diagram — One Wait State (8XC196MC, MD) ...............................15-19
READY Timing Diagram — One Wait State (8XC196MH).......................................15-20
15-10 Standard Bus Control ...............................................................................................15-22
15-11 Decoding WRL# and WRH#.....................................................................................15-22
15-12 8-bit System with Flash and RAM ............................................................................15-23
15-13 16-bit System with Dynamic Bus Width....................................................................15-24
15-14 Write Strobe Mode ...................................................................................................15-25
15-15 16-bit System with Writes to Byte-wide RAMs .........................................................15-26
15-16 Address Valid Strobe Mode......................................................................................15-27
15-17 Comparison of ALE and ADV# Bus Cycles..............................................................15-27
15-18 8-bit System with Flash ............................................................................................15-28
15-19 16-bit System with EPROM......................................................................................15-29
15-20 Timings of Address Valid with Write Strobe Mode ...................................................15-30
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FIGURES
Figure
15-21 16-bit System with RAM ...........................................................................................15-31
15-22 System Bus Timing ..................................................................................................15-32
16-1
16-2
16-3
16-4
16-5
16-6
16-7
16-8
16-9
Unerasable PROM (USFR) Register..........................................................................16-7
Programming Pulse Width (PPW) Register................................................................16-8
Modified Quick-pulse Algorithm................................................................................16-10
Pin Functions in Programming Modes......................................................................16-11
Slave Programming Circuit.......................................................................................16-16
Chip Configuration Registers (CCRs).......................................................................16-18
Address/Command Decoding Routine .....................................................................16-20
Program Word Routine.............................................................................................16-21
Program Word Waveform.........................................................................................16-22
16-10 Dump Word Routine.................................................................................................16-23
16-11 Dump Word Waveform.............................................................................................16-24
16-12 Auto Programming Circuit ........................................................................................16-26
16-13 Auto Programming Routine......................................................................................16-28
16-14 PCCB and UPROM Programming Circuit ................................................................16-31
16-15 Run-time Programming Code Example....................................................................16-33
B-1
B-2
B-3
B-4
B-5
B-6
B-7
B-8
8XC196MC 64-lead Shrink DIP (SDIP) Package........................................................ B-3
8XC196MC 84-lead PLCC Package ........................................................................... B-4
8XC196MC 80-lead Shrink EIAJ/QFP Package.......................................................... B-5
8XC196MD 84-lead PLCC Package ........................................................................... B-7
8XC196MD 80-lead Shrink EIAJ/QFP Package.......................................................... B-8
8XC196MH 64-lead Shrink DIP (SDIP) Package...................................................... B-10
8XC196MH 84-lead PLCC Package ......................................................................... B-11
8XC196MH 80-lead Shrink EIAJ/QFP Package........................................................ B-12
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8XC196MC, MD, MH USER’S MANUAL
TABLES
Table
Page
Handbooks and Product Information............................................................................1-6
1-1
1-2
1-3
1-4
1-5
2-1
2-2
3-1
3-2
3-3
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
5-11
5-13
5-14
5-15
5-16
6-1
6-2
6-3
6-4
6-5
6-6
6-7
Application Notes, Application Briefs, and Article Reprints ..........................................1-6
®
MCS 96 Microcontroller Datasheets (Commercial/Express)......................................1-7
®
MCS 96 Microcontroller Datasheets (Automotive) .....................................................1-7
®
MCS 96 Microcontroller Quick References ................................................................1-8
Features of the 8XC196Mx Product Family..................................................................2-2
State Times at Various Frequencies ............................................................................2-8
Operand Type Definitions.............................................................................................3-1
Equivalent Operand Types for Assembly and C Programming Languages .................3-2
Definition of Temporary Registers................................................................................3-6
Memory Map ...............................................................................................................4-2
Special-purpose Memory Addresses............................................................................4-3
Memory-mapped SFRs ................................................................................................4-5
Peripheral SFRs — 8XC196MC...................................................................................4-6
Peripheral SFRs — 8XC196MD...................................................................................4-7
Peripheral SFRs — 8XC196MH...................................................................................4-8
Register File Memory Addresses ..............................................................................4-10
CPU SFRs..................................................................................................................4-11
Selecting a Window of Peripheral SFRs.....................................................................4-13
Selecting a Window of the Upper Register File..........................................................4-14
Windows.....................................................................................................................4-15
Windowed Base Addresses .......................................................................................4-15
Interrupt Signals ...........................................................................................................5-3
Interrupt and PTS Control and Status Registers ..........................................................5-3
Interrupt Sources, Vectors, and Priorities.....................................................................5-5
Execution Times for PTS Cycles................................................................................5-12
Single Transfer Mode PTSCB....................................................................................5-30
Block Transfer Mode PTSCB .....................................................................................5-30
A/D Scan Mode Command/Data Table......................................................................5-34
Command/Data Table (Example 1)............................................................................5-36
A/D Scan Mode PTSCB (Example 1).........................................................................5-36
Command/Data Table (Example 2)............................................................................5-37
A/D Scan Mode PTSCB (Example 2).........................................................................5-37
SSIO Transmit Mode PTSCBs...................................................................................5-45
SSIO Receive Mode PTSCBs....................................................................................5-48
ASIO Transmit Mode PTSCBs...................................................................................5-52
ASIO Receive Mode PTSCBs....................................................................................5-56
Device I/O Ports ...........................................................................................................6-1
Standard Input-only Port Pins ......................................................................................6-2
Input-only Port Registers..............................................................................................6-3
Bidirectional Port Pins ..................................................................................................6-5
Bidirectional Port Control and Status Registers ...........................................................6-6
Logic Table for Bidirectional Ports in I/O Mode............................................................6-9
Logic Table for Bidirectional Ports in Special-function Mode .......................................6-9
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CONTENTS
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TABLES
Table
6-8
6-9
Control Register Values for Each Configuration.........................................................6-11
Port Configuration Example .......................................................................................6-11
Port Pin States After Reset and After Example Code Execution................................6-12
Ports 3 and 4 Pins......................................................................................................6-14
Ports 3 and 4 Control and Status Registers ...............................................................6-14
Logic Table for Ports 3 and 4 as Open-drain I/O........................................................6-16
Standard Output-only Port Pins..................................................................................6-17
Output-only Port Control Register ..............................................................................6-17
Serial Port Signals........................................................................................................7-2
Serial Port Control and Status Registers......................................................................7-2
SPx_BAUD Values When Using XTAL1 at 16 MHz...................................................7-14
Frequency Generator Signal ........................................................................................8-2
Frequency Generator Control and Status Registers ...................................................8-2
Waveform Generator Signals.......................................................................................9-3
Waveform Generator Control and Status Registers....................................................9-3
Operation in Center-aligned and Edge-aligned Modes ................................................9-8
Register Updates..........................................................................................................9-8
Output Configuration ..................................................................................................9-12
PWM Signals..............................................................................................................10-2
PWM Control and Status Registers............................................................................10-3
PWM Output Frequencies (FPWM)...............................................................................10-5
PWM Output Alternate Functions...............................................................................10-8
EPA Channels............................................................................................................11-1
EPA and Timer/Counter Signals.................................................................................11-2
EPA Control and Status Registers .............................................................................11-3
Quadrature Mode Truth Table....................................................................................11-8
Action Taken When a Valid Edge Occurs ................................................................11-12
Example EPA Control Register Settings for Channels 1, 3, or 5..............................11-18
A/D Converter Pins.....................................................................................................12-2
A/D Control and Status Registers...............................................................................12-2
Minimum Required Signals.........................................................................................13-1
I/O Port Configuration Guide ......................................................................................13-2
Selecting the Watchdog Reset Interval (8XC196MH only)......................................13-13
Operating Mode Control Signals ................................................................................14-1
Operating Mode Control and Status Registers...........................................................14-2
External Memory Interface Signals.............................................................................15-1
External Memory Interface Registers .........................................................................15-4
Register Settings for Configuring External Memory Interface Signals........................15-5
BUSWIDTH Signal Timing Definitions......................................................................15-13
READY Signal Timing Definitions.............................................................................15-20
Bus-control Modes ...................................................................................................15-21
AC Timing Symbol Definitions..................................................................................15-33
External Memory Systems Must Meet These Specifications....................................15-33
Microcontroller Meets These Specifications.............................................................15-34
6-10
6-11
6-12
6-13
6-14
6-15
7-1
7-2
7-3
8-1
8-2
9-1
9-2
9-3
9-4
9-5
10-1
10-2
10-3
10-4
11-1
11-2
11-3
11-4
11-5
11-6
12-1
12-2
13-1
13-2
13-3
14-1
14-2
15-1
15-2
15-3
15-4
15-5
15-6
15-7
15-8
15-9
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8XC196MC, MD, MH USER’S MANUAL
TABLES
Table
Page
87C196Mx OTPROM Memory Map ..........................................................................16-3
16-1
16-2
16-3
16-4
16-5
16-6
16-7
16-8
16-9
Memory Protection for Normal Operating Mode.........................................................16-4
Memory Protection Options for Programming Modes ................................................16-5
UPROM Programming Values and Locations for Slave Mode...................................16-7
Example PPW_VALUE Calculations..........................................................................16-9
Pin Descriptions .......................................................................................................16-11
PMODE Values ........................................................................................................16-13
Device Signature Word and Programming Voltages................................................16-16
Slave Programming Mode Memory Map..................................................................16-17
16-10 Timing Mnemonics ...................................................................................................16-24
16-11
16-12
16-13
A-1
A-1
A-2
A-3
A-4
A-5
A-6
A-7
A-8
A-9
B-1
B-2
B-3
B-4
B-5
8XC196MC/MD Auto Programming Memory Map ..................................................16-27
8XC196MH Auto Programming Memory Map.........................................................16-27
PCCB and UPROM Programming Values...............................................................16-32
Opcode Map (Left Half) ............................................................................................... A-2
Opcode Map (Right Half)............................................................................................. A-3
Processor Status Word (PSW) Flags.......................................................................... A-4
Effect of PSW Flags or Specified Conditions on Conditional Jump Instructions......... A-5
PSW Flag Setting Symbols ......................................................................................... A-5
Operand Variables ...................................................................................................... A-6
Instruction Set ............................................................................................................. A-7
Instruction Opcodes .................................................................................................. A-41
Instruction Lengths and Hexadecimal Opcodes........................................................ A-47
Instruction Execution Times (in State Times)............................................................ A-52
Signal Name Changes ................................................................................................ B-1
8XC196MC Signals Arranged by Functional Categories............................................. B-2
8XC196MD Signals Arranged by Functional Categories............................................. B-6
8XC196MH Signals Arranged by Functional Categories............................................. B-9
Description of Columns of Table B-6......................................................................... B-13
Signal Descriptions.................................................................................................... B-13
Definition of Status Symbols ..................................................................................... B-23
8XC196MC and MD Default Signal Conditions......................................................... B-23
8XC196MH Default Signal Conditions....................................................................... B-25
Modules and Related Registers ..................................................................................C-1
Register Name, Address, and Reset Status................................................................C-2
COMPx_TIME Addresses and Reset Values............................................................ C-17
EPAx_CON Addresses and Reset Values................................................................ C-20
EPAx_TIME Addresses and Reset Values................................................................ C-21
Px_DIR Addresses and Reset Values....................................................................... C-30
Px_MODE Addresses and Reset Values.................................................................. C-31
Special-function Signals for Ports 1, 2, 5, 6............................................................... C-32
Px_PIN Addresses and Reset Values....................................................................... C-33
Px_REG Addresses and Reset Values..................................................................... C-34
Output Configuration ................................................................................................. C-65
WSR Settings and Direct Addresses for Windowable SFRs..................................... C-68
B-6
B-7
B-8
B-9
C-1
C-2
C-3
C-4
C-5
C-6
C-7
C-8
C-9
C-10
C-11
C-12
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1
Guide to This Manual
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CHAPTER 1
GUIDE TO THIS MANUAL
This manual describes the 8XC196MC, 8XC196MD, and 8XC196MH embedded microcontrol-
lers. It is intended for use by both software and hardware designers familiar with the principles
of microcontrollers. This chapter describes what you’ll find in this manual, lists other documents
that may be useful, and explains how to access the support services we provide to help you com-
plete your design.
1.1 MANUAL CONTENTS
This manual contains several chapters and appendixes, a glossary, and an index. This chapter,
Chapter 1, provides an overview of the manual. This section summarizes the contents of the re-
maining chapters and appendixes. The remainder of this chapter describes notational conventions
and terminology used throughout the manual, provides references to related documentation, de-
scribes customer support services, and explains how to access information and assistance.
Chapter 2 — Architectural Overview — provides an overview of the device hardware. It de-
scribes the core, internal timing, internal peripherals, and special operating modes.
Chapter 3 — Programming Considerations — provides an overview of the instruction set, de-
scribes general standards and conventions, and defines the operand types and addressing modes
®
supported by the MCS 96 microcontroller family. (For additional information about the instruc-
tion set, see Appendix A.)
Chapter 4 — Memory Partitions — describes the addressable memory space of the device. It
describes the memory partitions and explains how to use windows to increase the amount of
memory that can be accessed with register-direct instructions.
Chapter 5 — Standard and PTS Interrupts — describes the interrupt control circuitry, priority
scheme, and timing for standard and peripheral transaction server (PTS) interrupts. It also ex-
plains interrupt programming and control.
Chapter 6 — I/O Ports — describes the input/output ports and explains how to configure the
ports for input, output, or special functions.
Chapter 7 — Serial I/O (SIO) Port — describes the 8XC196MH’s asynchronous/synchronous
serial I/O (SIO) port and explains how to program it.
Chapter 8 — Frequency Generator — describes the 8XC196MD’s frequency generator and ex-
plains how to configure it. For additional information and application examples, consult AP-483,
Application Examples Using the 8XC196MC/MD Microcontroller (order number 272282).
1-1
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8XC196MC, MD, MH USER’S MANUAL
Chapter 9 — Waveform Generator — describes the waveform generator and explains how to
configure it. For additional information and application examples, consult AP-483, Application
Examples Using the 8XC196MC/MD Microcontroller (order number 272282).
Chapter 10 — Pulse-width Modulator — provides a functional overview of the pulse width
modulator (PWM) modules, describes how to program them, and provides sample circuitry for
converting the PWM outputs to analog signals.
Chapter 11 — Event Processor Array (EPA) — describes the event processor array, a tim-
er/counter-based, high-speed input/output unit. It describes the timer/counters and explains how
to program the EPA and how to use the EPA to produce pulse-width modulated (PWM) outputs.
Chapter 12 — Analog-to-digital (A/D) Converter — provides an overview of the analog-to-
digital (A/D) converter and describes how to program the converter, read the conversion results,
and interface with external circuitry.
Chapter 13 — Minimum Hardware Considerations — describes options for providing the ba-
sic requirements for device operation within a system, discusses other hardware considerations,
and describes device reset options.
Chapter 14 — Special Operating Modes — provides an overview of the idle, powerdown,
and on-circuit emulation (ONCE) modes and describes how to enter and exit each mode.
Chapter 15 — Interfacing with External Memory — lists the external memory signals and de-
scribes the registers that control the external memory interface. It discusses the bus width and
memory configurations, the bus-hold protocol, write-control modes, and internal wait states and
ready control. Finally, it provides timing information for the system bus.
Chapter 16 — Programming the Nonvolatile Memory — provides recommended circuits, the
corresponding memory maps, and flow diagrams. It also provides procedures for auto program-
ming.
Appendix A — Instruction Set Reference — provides reference information for the instruction
set. It describes each instruction; defines the processor status word (PSW) flags; shows the rela-
tionships between instructions and PSW flags; and lists hexadecimal opcodes, instruction
lengths, and execution times. (For additional information about the instruction set, see Chapter 3,
“Programming Considerations.”)
Appendix B — Signal Descriptions — provides reference information for the device pins, in-
cluding descriptions of the pin functions, reset status of the I/O and control pins, and package pin
assignments.
1-2
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GUIDE TO THIS MANUAL
Appendix C — Registers — provides a compilation of all device special-function registers
(SFRs) arranged alphabetically by register mnemonic. It also includes tables that list the win-
dowed direct addresses for all SFRs in each possible window.
Glossary — defines terms with special meaning used throughout this manual.
Index — lists key topics with page number references.
1.2 NOTATIONAL CONVENTIONS AND TERMINOLOGY
The following notations and terminology are used throughout this manual. The Glossary defines
other terms with special meanings.
#
The pound symbol (#) has either of two meanings, depending on the
context. When used with a signal name, the symbol means that the
signal is active low. When used in an instruction, the symbol prefixes
an immediate value in immediate addressing mode.
assert and deassert
The terms assert and deassert refer to the act of making a signal
active (enabled) and inactive (disabled), respectively. The active
polarity (low or high) is defined by the signal name. Active-low
signals are designated by a pound symbol (#) suffix; active-high
signals have no suffix. To assert RD# is to drive it low; to assert ALE
is to drive it high; to deassert RD# is to drive it high; to deassert ALE
is to drive it low.
clear and set
instructions
The terms clear and set refer to the value of a bit or the act of giving
it a value. If a bit is clear, its value is “0”; clearing a bit gives it a “0”
value. If a bit is set, its value is “1”; setting a bit gives it a “1” value.
Instruction mnemonics are shown in upper case to avoid confusion.
In general, you may use either upper case or lower case when
programming. Consult the manual for your assembler or compiler to
determine its specific requirements.
italics
Italics identify variables and introduce new terminology. The context
in which italics are used distinguishes between the two possible
meanings.
Variables in registers and signal names are commonly represented by
x and y, where x represents the first variable and y represents the
second variable. For example, in register Px_MODE.y, x represents
the variable that identifies the specific port associated with the
register, and y represents the register bit variable (7:0 or 15:0).
Variables must be replaced with the correct values when configuring
or programming registers or identifying signals.
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numbers
Hexadecimal numbers are represented by a string of hexadecimal
digits followed by the character H. Decimal and binary numbers are
represented by their customary notations. (That is, 255 is a decimal
number and 1111 1111 is a binary number. In some cases, the letter B
is appended to binary numbers for clarity.)
register bits
register names
reserved bits
Bit locations are indexed by 7:0 (or 15:0), where bit 0 is the least-
significant bit and bit 7 (or 15) is the most-significant bit. An
individual bit is represented by the register name, followed by a
period and the bit number. For example, WSR.7 is bit 7 of the
window selection register. In some discussions, bit names are used.
Register mnemonics are shown in upper case. For example, TIMER2
is the timer 2 register; timer 2 is the timer. A register name containing
a lowercase italic character represents more than one register. For
example, the x in Px_REG indicates that the register name refers to
any of the port data registers.
Certain bits are described as reserved bits. In illustrations, reserved
bits are indicated with a dash (—). These bits are not used in this
device, but they may be used in future implementations. To help
ensure that a current software design is compatible with future imple-
mentations, reserved bits should be cleared (given a value of “0”) or
left in their default states, unless otherwise noted. Do not rely on the
values of reserved bits; consider them undefined.
signal names
Signal names are shown in upper case. When several signals share a
common name, an individual signal is represented by the signal name
followed by a number. For example, the EPA signals are named
EPA0, EPA1, EPA2, etc. Port pins are represented by the port abbre-
viation, a period, and the pin number (e.g., P1.0, P1.1); a range of
pins is represented by Px.y:z (e.g., P1.4:0 represents five port pins:
P1.4, P1.3, P1.2, P1.1, P1.0). A pound symbol (#) appended to a
signal name identifies an active-low signal.
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units of measure
The following abbreviations are used to represent units of measure:
A
amps, amperes
DCV
direct current volts
Kbytes kilobytes
kHz
kΩ
mA
kilohertz
kilo-ohms
milliamps, milliamperes
Mbytes megabytes
MHz
ms
mW
ns
megahertz
milliseconds
milliwatts
nanoseconds
picofarads
pF
W
watts
V
volts
µA
µF
µs
microamps, microamperes
microfarads
microseconds
microwatts
µW
X
Uppercase X (no italics) represents an unknown value or an
irrelevant (“don’t care”) state or condition. The value may be either
binary or hexadecimal, depending on the context. For example,
2XAFH (hex) indicates that bits 11:8 are unknown; 10XXB (binary)
indicates that the two least-significant bits are unknown.
1.3 RELATED DOCUMENTS
The tables in this section list additional documents that you may find useful in designing systems
incorporating MCS 96 microcontrollers. These are not comprehensive lists, but are a representa-
tive sample of relevant documents. For a complete list of available printed documents, please or-
der the literature catalog (order number 210621). To order documents, please call the Intel
literature center for your area (telephone numbers are listed on page 1-11).
1-5
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Table 1-1. Handbooks and Product Information
Title and Description
Intel Embedded Quick Reference Guide
Order Number
272439
240691
240952
240897
Solutions for Embedded Applications Guide
Data on Demand fact sheet
Data on Demand annual subscription (6 issues; Windows* version)
Complete set of Intel handbooks on CD-ROM.
Handbook Set — handbooks and product overview
231003
Complete set of Intel’s product line handbooks. Contains datasheets, application
notes, article reprints and other design information on microprocessors, periph-
erals, embedded controllers, memory components, single-board computers,
microcommunications, software development tools, and operating systems.
Automotive Products †
231792
270648
Application notes and article reprints on topics including the MCS 51 and MCS 96
microcontrollers. Documents in this handbook discuss hardware and software
implementations and present helpful design techniques.
Embedded Applications handbook (2 volume set) †
Datasheets, architecture descriptions, and application notes on topics including
flash memory devices, networking chips, and MCS 51 and MCS 96 microcon-
trollers. Documents in this handbook discuss hardware and software implementa-
tions and present helpful design techniques.
Embedded Microcontrollers †
270646
296467
210830
240800
272326
Datasheets and architecture descriptions for Intel’s three industry-standard micro-
controllers, the MCS 48, MCS 51, and MCS 96 microcontrollers.
Peripheral Components †
Comprehensive information on Intel’s peripheral components, including
datasheets, application notes, and technical briefs.
Flash Memory (2 volume set) †
A collection of datasheets and application notes devoted to techniques and
information to help design semiconductor memory into an application or system.
Packaging †
Detailed information on the manufacturing, applications, and attributes of a variety
of semiconductor packages.
Development Tools Handbook
Information on third-party hardware and software tools that support Intel’s
embedded microcontrollers.
† Included in handbook set (order number 231003)
Table 1-2. Application Notes, Application Briefs, and Article Reprints
Title
Order Number
AB-71, Using the SIO on the 8XC196MH (application brief)
AP-125, Designing Microcontroller Systems for Electrically Noisy Environments †††
AP-155, Oscillators for Microcontrollers †††
272594
210313
230659
270056
AR-375, Motor Controllers Take the Single-Chip Route (article reprint)
† Included in Automotive Products handbook (order number 231792)
†† Included in Embedded Applications handbook (order number 270648)
††† Included in Automotive Products and Embedded Applications handbooks
1-6
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Table 1-2. Application Notes, Application Briefs, and Article Reprints (Continued)
Title
Order Number
AP-406, MCS® 96 Analog Acquisition Primer †††
AP-445, 8XC196KR Peripherals: A User’s Point of View †
270365
270873
270968
AP-449, A Comparison of the Event Processor Array (EPA) and High Speed
Input/Output (HSIO) Unit †
AP-475, Using the 8XC196NT ††
AP-477, Low Voltage Embedded Design ††
272315
272324
272282
272595
272324
272680
AP-483, Application Examples Using the 8XC196MC/MD Microcontroller
AP-700, Intel Fuzzy Logic Tool Simplifies ABS Design †
AP-711, EMI Design Techniques for Microcontrollers in Automotive Applications
AP-715, Interfacing an I2C Serial EEPROM to an MCS® 96 Microcontroller
† Included in Automotive Products handbook (order number 231792)
†† Included in Embedded Applications handbook (order number 270648)
††† Included in Automotive Products and Embedded Applications handbooks
®
Table 1-3. MCS 96 Microcontroller Datasheets (Commercial/Express)
Title
Order Number
8XC196KR/KQ/JR/JQ Commercial/Express CHMOS Microcontroller †
8XC196KT Commercial CHMOS Microcontroller †
87C196KT/87C196KS 20 MHz Advanced 16-Bit CHMOS Microcontroller †
8XC196MC Industrial Motor Control Microcontroller †
87C196MD Industrial Motor Control CHMOS Microcontroller †
8XC196NP Commercial CHMOS 16-Bit Microcontroller †
8XC196NT CHMOS Microcontroller with 1-Mbyte Linear Address Space †
270912
272266
272513
272323
270946
272459
272267
272644
80C196NU Commercial CHMOS 16-Bit Microcontroller
† Included in Embedded Microcontrollers handbook (order number 270646)
®
Table 1-4. MCS 96 Microcontroller Datasheets (Automotive)
Title and Description
Order Number
87C196CA/87C196CB 20 MHz Advanced 16-Bit CHMOS Microcontroller with
Integrated CAN 2.0 †
272405
87C196JT 20 MHz Advanced 16-Bit CHMOS Microcontroller †
87C196JV 20 MHz Advanced 16-Bit CHMOS Microcontroller †
272529
272580
270827
87C196KR/KQ, 87C196JV/JT, 87C196JR/JQ Advanced 16-Bit CHMOS
Microcontroller †
87C196KT/87C196KS Advanced 16-Bit CHMOS Microcontroller †
87C196KT/KS 20 MHz Advanced 16-Bit CHMOS Microcontroller †
† Included in Automotive Products handbook (order number 231792)
270999
272513
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1.4.4 World Wide Web
We offer a variety of information through the World Wide Web (URL:http://www.intel.com/). Se-
lect “Embedded Design Products” from the Intel home page.
1.5 TECHNICAL SUPPORT
In the U.S. and Canada, technical support representatives are available to answer your questions
between 5 a.m. and 5 p.m. PST. You can also fax your questions to us. (Please include your voice
telephone number and indicate whether you prefer a response by phone or by fax). Outside the
U.S. and Canada, please contact your local distributor.
1-800-628-8686
916-356-7599
U.S. and Canada
U.S. and Canada
U.S. and Canada
916-356-6100 (fax)
1.6 PRODUCT LITERATURE
You can order product literature from the following Intel literature centers.
1-800-548-4725
708-296-9333
U.S. and Canada
U.S. (from overseas)
Europe (U.K.)
Germany
44(0)1793-431155
44(0)1793-421333
44(0)1793-421777
81(0)120-47-88-32
France
Japan (fax only)
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2
Architectural
Overview
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CHAPTER 2
ARCHITECTURAL OVERVIEW
The 16-bit 8XC196MC, 8XC196MD, and 8XC196MH CHMOS microcontrollers are designed
to handle high-speed calculations and fast input/output (I/O) operations. They share a common
®
architecture and instruction set with other members of the MCS 96 microcontroller family.
NOTE
This manual describes a family of microcontrollers. For brevity, the name
8XC196Mx is used when the discussion applies to all family members. When
information applies to specific microcontrollers, individual product names are
used.
2.1 TYPICAL APPLICATIONS
MCS 96 microcontrollers are typically used for high-speed event control systems. Commercial
applications include modems, motor-control systems, printers, photocopiers, air conditioner con-
trol systems, disk drives, and medical instruments. Automotive customers use MCS 96 microcon-
trollers in engine-control systems, airbags, suspension systems, and antilock braking systems
(ABS).
2.2 MICROCONTROLLER FEATURES
Table 2-1 lists the features of each member of the 8XC196Mx family.
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Table 2-1. Features of the 8XC196Mx Product Family
OTPROM/ Register
SIO
Ports
(Note 3) (Note 4)
PWM
Channels
External
Interrupt
Pins
ROM
Bytes
RAM
Bytes
I/O
Pins Pins
EPA
A/D
Channels
Device
Pins
(Note 1)
(Note 2)
8XC196MH
8XC196MH
8XC196MH
8XC196MC
8XC196MC
8XC196MC
8XC196MD
8XC196MD
NOTES:
84
80
64
84
80
64
84
80
32 K
32 K
32 K
16 K
16 K
16 K
16 K
16 K
744
744
744
488
488
488
488
488
52
52
50
53
53
49
64
64
6
6
2
2
2
0
0
0
0
0
8
8
7
8
8
7
9
9
8
1
1
1
1
1
1
1
1
8
6
8
8
13
13
12
14
14
8
7
12
12
1. Nonvolatile memory is optional. The second character of the device name indicates the presence and
type of nonvolatile memory. 80C196Mx = none; 83C196Mx = ROM; 87C196Mx = OTPROM.
2. Register RAM amounts include the 24 bytes allocated to core SFRs and the stack pointer.
3. The 8XC196MC and 8XC196MD have no serial I/O ports, but have PTS modes that allow asynchro-
nous or synchronous serial communication.
4. The number of PWM channels includes the outputs from the PWM peripheral and the waveform gen-
erator. For the 8XC196MD, it also includes the output from the frequency generator.
2.3 FUNCTIONAL OVERVIEW
Figure 2-1 shows the major blocks within the microcontroller. The core of the microcontroller
(Figure 2-2) consists of the central processing unit (CPU) and memory controller. The CPU con-
tains the register file and the register arithmetic-logic unit (RALU). A 16-bit internal bus connects
the CPU to both the memory controller and the interrupt controller. An extension of this bus con-
nects the CPU to the internal peripheral modules. In addition, an 8-bit internal bus transfers in-
struction bytes from the memory controller to the instruction register in the RALU.
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Optional
ROM
Interrupt
Controller
Core
Clock and
Power Mgmt.
PTS
I/O
EPA
PWM
WG
A/D
WDT
FG
SIO
Note:
The frequency generator is unique to the 8XC196MD.
The serial I/O port is unique to the 8XC196MH.
A2798-02
Figure 2-1. 8XC196Mx Block Diagram
Memory Controller
Prefetch Queue
Slave PC
CPU
Register File
RALU
Microcode
Engine
Register
RAM
Address Register
Data Register
ALU
Master PC
PSW
CPU SFRs
Bus Controller
Registers
A2797-01
Figure 2-2. Block Diagram of the Core
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2.3.1 CPU Control
The CPU is controlled by the microcode engine, which instructs the RALU to perform operations
using bytes, words, or double-words from either the 256-byte lower register file or through a win-
dow that directly accesses the upper register file. (See Chapter 4, “Memory Partitions,” for more
information about the register file and windowing.) CPU instructions move from the 4-byte
prefetch queue in the memory controller into the RALU’s instruction register. The microcode en-
gine decodes the instructions and then generates the sequence of events that cause desired func-
tions to occur.
2.3.2 Register File
The register file is divided into an upper and a lower file. In the lower register file, the lowest 24
bytes are allocated to the CPU’s special-function registers (SFRs) and the stack pointer, while the
remainder is available as general-purpose register RAM. The upper register file contains only
general-purpose register RAM. The register RAM can be accessed as bytes, words, or double-
words.
The RALU accesses the upper and lower register files differently. The lower register file is always
directly accessible with direct addressing (see “Addressing Modes” on page 3-5). The upper reg-
ister file is accessible with direct addressing only when windowing is enabled. Windowing is a
technique that maps blocks of the upper register file into a window in the lower register file. See
Chapter 4, “Memory Partitions,” for more information about the register file and windowing.
2.3.3 Register Arithmetic-logic Unit (RALU)
The RALU contains the microcode engine, the 16-bit arithmetic logic unit (ALU), the master pro-
gram counter (PC), the processor status word (PSW), and several registers. The registers in the
RALU are the instruction register, a constants register, a bit-select register, a loop counter, and
three temporary registers (the upper-word, lower-word, and second-operand registers).
The PSW contains one bit (PSW.1) that globally enables or disables servicing of all maskable in-
terrupts, one bit (PSW.2) that enables or disables the peripheral transaction server (PTS), and six
Boolean flags that reflect the state of your program. Appendix A, “Instruction Set Reference,”
provides a detailed description of the PSW.
All registers, except the 3-bit bit-select register and the 6-bit loop counter, are either 16 or 17 bits
(16 bits plus a sign extension). Some of these registers can reduce the ALU’s workload by per-
forming simple operations.
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ARCHITECTURAL OVERVIEW
The RALU uses the upper- and lower-word registers together for the 32-bit instructions and as
temporary registers for many instructions. These registers have their own shift logic and are used
for operations that require logical shifts, including normalize, multiply, and divide operations.
The six-bit loop counter counts repetitive shifts. The second-operand register stores the second
operand for two-operand instructions, including the multiplier during multiply operations and the
divisor during divide operations. During subtraction operations, the output of this register is com-
plemented before it is moved into the ALU.
The RALU speeds up calculations by storing constants (e.g., 0, 1, and 2) in the constants register
so that they are readily available when complementing, incrementing, or decrementing bytes or
words. In addition, the constants register generates single-bit masks, based on the bit-select reg-
ister, for bit-test instructions.
2.3.3.1
Code Execution
The RALU performs most calculations for the microcontroller, but it does not use an accumula-
tor. Instead it operates directly on the lower register file, which essentially provides 256 accumu-
lators. Because data does not flow through a single accumulator, the microcontroller’s code
executes faster and more efficiently.
2.3.3.2
Instruction Format
MCS 96 microcontrollers combine a large set of general-purpose registers with a three-operand
instruction format. This format allows a single instruction to specify two source registers and a
separate destination register. For example, the following instruction multiplies two 16-bit vari-
ables and stores the 32-bit result in a third variable.
MUL RESULT, FACTOR_1, FACTOR_2
;multiply FACTOR_1 and FACTOR_2
;and store answer in RESULT
;(RESULT)←(FACTOR_1 × FACTOR_2)
An 80C186 microprocessor requires four instructions to accomplish the same operation. The fol-
lowing example shows the equivalent code for an 80C186 microprocessor.
MOV AX, FACTOR_1
MUL FACTOR_2
;move FACTOR_1 into accumulator (AX)
;(AX)←FACTOR1
;multiply FACTOR_2 and AX
;(DX:AX)←(AX)×(FACTOR_2)
;move lower byte into RESULT
;(RESULT)←(AX)
MOV RESULT, AX
MOV RESULT+2, DX
;move upper byte into RESULT+2
;(RESULT+2)←(DX)
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2.3.4 Memory Interface Unit
The RALU communicates with all memory, except the register file and peripheral SFRs, through
the memory controller. (It communicates with the upper register file through the memory control-
ler except when windowing is used; see Chapter 4, “Memory Partitions.”) The memory controller
contains the prefetch queue, the slave program counter (slave PC), address and data registers, and
the bus controller.
The bus controller drives the memory bus, which consists of an internal memory bus and the ex-
ternal address/data bus. The bus controller receives memory-access requests from either the
RALU or the prefetch queue; queue requests always have priority. This queue is transparent to
the RALU and your software.
NOTE
When using a logic analyzer to debug code, remember that instructions are
preloaded into the prefetch queue and are not necessarily executed
immediately after they are fetched.
When the bus controller receives a request from the queue, it fetches the code from the address
contained in the slave PC. The slave PC increases execution speed because the next instruction
byte is available immediately and the processor need not wait for the master PC to send the ad-
dress to the memory controller. If a jump, interrupt, call, or return changes the address sequence,
the master PC loads the new address into the slave PC, then the CPU flushes the queue and con-
tinues processing.
2.3.5 Interrupt Service
The microcontroller’s flexible interrupt-handling system has two main components: the program-
mable interrupt controller and the peripheral transaction server (PTS). The programmable inter-
rupt controller has a hardware priority scheme that can be modified by your software. Interrupts
that go through the interrupt controller are serviced by interrupt service routines that you provide.
The peripheral transaction server (PTS), a microcoded hardware interrupt processor, provides
high-speed, low-overhead interrupt handling. You can configure most interrupts (except NMI,
trap, and unimplemented opcode) to be serviced by the PTS instead of the interrupt controller.
The PTS can transfer bytes or words, either individually or in blocks, between any memory loca-
tions, manage multiple analog-to-digital (A/D) conversions, and can generate pulse-width mod-
ulated (PWM) signals. The 8XC196MC and 8XC196MD have additional modes that allow
asynchronous or synchronous serial communication. PTS interrupts have a higher priority than
standard interrupts and may temporarily suspend interrupt service routines. See Chapter 5, “Stan-
dard and PTS Interrupts,” for more information.
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ARCHITECTURAL OVERVIEW
2.4 INTERNAL TIMING
The clock circuitry (Figure 2-3) receives an input clock signal on XTAL1 provided by an external
crystal or oscillator and divides the frequency by two. The clock generators accept the divided
input frequency from the divide-by-two circuit and produce two nonoverlapping internal timing
signals, PH1 and PH2. These signals are active when high.
.
Disable Clock Input
(Powerdown)
FXTAL1
Divide-by-two
XTAL1
Circuit
Disable Clocks
(Powerdown)
XTAL2
Peripheral Clocks (PH1, PH2)
Clock
Generators
CLKOUT
Disable
Oscillator
CPU Clocks (PH1, PH2)
(Powerdown)
Disable Clocks
(Idle, Powerdown)
NOTE: The CLKOUT pin is unique to the 8XC196MC and MD.
A3115-02
Figure 2-3. Clock Circuitry
The rising edges of PH1 and PH2 generate the internal CLKOUT signal (Figure 2-4). The clock
circuitry routes separate internal clock signals to the CPU and the peripherals to provide flexibil-
ity in power management. (“Reducing Power Consumption” on page 14-3 describes the power
management modes.) The 8XC196MC and 8XC196MD microcontrollers output the CLKOUT
signal on the CLKOUT pin. Because of the complex logic in the clock circuitry, the signal on the
CLKOUT pin is a delayed version of the internal CLKOUT signal. This delay varies with tem-
perature and voltage.
The 8XC196MH microcontroller has no CLKOUT pin. If your 8XC196MH design requires a
system clock, we recommend that you use an external oscillator and add external logic to generate
the system clock signal.
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XTAL1
T
T
XTAL1
XTAL1
1 State Time
1 State Time
PH1
PH2
CLKOUT
Phase 1
Phase 2
Phase 1
Phase 2
A0114-04
Figure 2-4. Internal Clock Phases
The combined period of phase 1 and phase 2 of the internal CLKOUT signal defines the basic
time unit known as a state time or state. Table 2-2 lists state time durations at various frequencies.
Table 2-2. State Times at Various Frequencies
FXTAL1
(Frequency Input to the
Divide-by-two Circuit)
State Time
8 MHz
12 MHz
16 MHz
250 ns
167 ns
125 ns
The following formulas calculate the frequency of PH1 and PH2, the duration of a state time, and
the duration of a clock period (TXTAL1).
FXTAL1
------------------
2
2
1
------------------
------------------
PH1 (in MHz) =
= PH2
State Time (in µs) =
T XTAL1
=
FXTAL1
FXTAL1
Because the microcontroller can operate at many frequencies, this manual defines time require-
ments (such as instruction execution times) in terms of state times rather than specific measure-
ments. Datasheets list AC characteristics in terms of clock periods (TXTAL1 or TOSC).
2.5 INTERNAL PERIPHERALS
The internal peripheral modules provide special functions for a variety of applications. This sec-
tion provides a brief description of the peripherals; subsequent chapters describe them in detail.
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2.5.1 I/O Ports
The 8XC196Mx microcontrollers have seven I/O ports, ports 0–6. The 8XC196MD has an addi-
tional port, port 7. Individual port pins are multiplexed to serve as standard I/O or to carry special-
function signals associated with an on-chip peripheral or an off-chip component. If a particular
special-function signal is not used in an application, the associated pin can be individually con-
figured to serve as a standard I/O pin. Ports 3 and 4 are exceptions; they are controlled at the port
level, not at the pin level. When the bus controller needs to use the address/data bus, it takes con-
trol of the ports. When the address/data bus is idle, you can use the ports for I/O.
Port 0 is an input-only port that is also the analog input for the A/D converter. On the 8XC196MH,
port 0 provides two pins for the EPA. On the 8XC196MC and 8XC196MD, port 1 is also an input-
only port that provides analog inputs for the A/D converter. On the 8XC196MH, port 1 is a bidi-
rectional port that shares pins with the serial I/O port.
Port 2 is a standard, bidirectional I/O port that provides pins for the EPA and timers. Port 7, which
is unique to the 8XC196MD, is a standard, bidirectional I/O port that provides additional pins for
the EPA and also provides pins for the frequency generator. Ports 3, 4, and 5 are memory-mapped,
bidirectional I/O ports. Ports 3 and 4 serve as the external address/data bus, while port 5 provides
bus-control signals. Port 6 is a standard, output-only port that provides pins for the pulse-width
modulator and waveform generator. Chapter 6, “I/O Ports,” describes the I/O ports in more detail.
2.5.2 Serial I/O (SIO) Port
The 8XC196MH microcontroller has a two-channel serial I/O port that shares pins with ports 1
and 2. (The 8XC196MC and 8XC196MD have no serial I/O ports, but have PTS modes that allow
asynchronous or synchronous serial communication. See Chapter 5, “Standard and PTS Inter-
rupts,” for more information.) The serial I/O (SIO) port is an asynchronous/synchronous port that
includes a universal asynchronous receiver and transmitter (UART). The UART has two synchro-
nous modes (modes 0 and 4) and three asynchronous modes (modes 1, 2, and 3) for both trans-
mission and reception. The asynchronous modes are full duplex, meaning that they can transmit
and receive data simultaneously. The receiver is buffered, so the reception of a second byte can
begin before the first byte is read. The transmitter is also buffered, allowing continuous transmis-
sions. The SIO port has two channels (channels 0 and 1) with identical signals and registers. See
Chapter 7, “Serial I/O (SIO) Port,” for details.
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2.5.3 Event Processor Array (EPA) and Timer/Counters
The event processor array (EPA) performs high-speed input and output functions associated with
its timer/counters. In the input mode, the EPA monitors an input for signal transitions. When an
event occurs, the EPA records the timer value associated with it. This is a capture event. In the
output mode, the EPA monitors a timer until its value matches that of a stored time value. When
a match occurs, the EPA triggers an output event, which can set, clear, or toggle an output pin.
This is a compare event. Both capture and compare events can initiate interrupts, which can be
serviced by either the interrupt controller or the PTS.
Timer 1 and timer 2 are both 16-bit up/down timer/counters that can be clocked internally or ex-
ternally. Each timer/counter is called a timer if it is clocked internally and a counter if it is clocked
externally. See Chapter 11, “Event Processor Array (EPA),” for additional information on the
EPA and timer/counters.
2.5.4 Pulse-width Modulator (PWM)
The output waveform from each PWM channel is a variable duty-cycle pulse. Several types of
motors require a PWM waveform for most efficient operation. When filtered, the PWM wave-
form produces a DC level that can change in 256 steps by varying the duty cycle. The number of
steps per PWM period is also programmable (8 bits). See Chapter 10, “Pulse-width Modulator,”
for more information.
2.5.5 Frequency Generator
The 8XC196MD has a peripheral not found on other 8XC196Mx microcontrollers — the fre-
quency generator. This peripheral produces a waveform with a fixed duty cycle (50%) and a pro-
grammable frequency (ranging from 4 kHz to 1 MHz with a 16 MHz input clock). See Chapter
8, “Frequency Generator,” for details.
2.5.6 Waveform Generator
A waveform generator simplifies the task of generating synchronized, pulse-width modulated
(PWM) outputs. This waveform generator is optimized for motion control applications such as
driving 3-phase AC induction motors, 3-phase DC brushless motors, or 4-phase stepping motors.
The waveform generator can produce three independent pairs of complementary PWM outputs,
which share a common carrier period, dead time, and operating mode. Once it is initialized, the
waveform generator operates without CPU intervention unless you need to change a duty cycle.
See Chapter 9, “Waveform Generator,” for more information.
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ARCHITECTURAL OVERVIEW
2.5.7 Analog-to-digital Converter
The analog-to-digital (A/D) converter converts an analog input voltage to a digital equivalent.
Resolution is either 8 or 10 bits; sample and convert times are programmable. Conversions can
be performed on the analog ground and reference voltage, and the results can be used to calculate
gain and zero-offset errors. The internal zero-offset compensation circuit enables automatic zero-
offset adjustment. The A/D also has a threshold-detection mode, which can be used to generate
an interrupt when a programmable threshold voltage is crossed in either direction. The A/D scan
mode of the PTS facilitates automated A/D conversions and result storage. See Chapter 12, “An-
alog-to-digital (A/D) Converter,” for more information.
2.5.8 Watchdog Timer
The watchdog timer is a 16-bit internal timer that resets the microcontroller if the software fails
to operate properly. See Chapter 13, “Minimum Hardware Considerations,” for more informa-
tion.
2.6 SPECIAL OPERATING MODES
In addition to the normal execution mode, the microcontroller operates in several special-purpose
modes. Idle and powerdown modes conserve power when the microcontroller is inactive. On-
circuit emulation (ONCE) mode electrically isolates the microcontroller from the system, and
several other modes provide programming options for nonvolatile memory. See Chapter 14,
“Special Operating Modes,” for more information about idle, powerdown, and ONCE modes, and
see Chapter 16, “Programming the Nonvolatile Memory,” for details about programming options.
2.6.1 Reducing Power Consumption
In idle mode, the CPU stops executing instructions, but the peripheral clocks remain active. Pow-
er consumption drops to about 40% of normal execution mode consumption. Either a hardware
reset or any enabled interrupt source will bring the microcontroller out of idle mode.
In powerdown mode, all internal clocks are frozen at logic state zero and the internal oscillator is
shut off. The register file and most peripherals retain their data if VCC is maintained. Power con-
sumption drops into the µW range.
2.6.2 Testing the Printed Circuit Board
The on-circuit emulation (ONCE) mode electrically isolates the microcontroller from the system.
By invoking the ONCE mode, you can test the printed circuit board while the microcontroller is
soldered onto the board.
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2.6.3 Programming the Nonvolatile Memory
MCS 96 microcontrollers that have internal OTPROM provide several programming options:
• Slave programming allows a master EPROM programmer to program and verify one or
more slave MCS 96 microcontrollers. Programming vendors and Intel distributors typically
use this mode to program a large number of microcontrollers with a customer’s code and
data.
• Auto programming allows an MCS 96 microcontroller to program itself with code and data
located in an external memory device. Customers typically use this low-cost method to
program a small number of microcontrollers after development and testing are complete.
• Run-time programming allows you to program individual nonvolatile memory locations
during normal code execution, under complete software control. Customers typically use
this mode to download a small amount of information to the microcontroller after the rest of
the array has been programmed. For example, you might use run-time programming to
download a unique identification number to a security device.
• ROM dump mode allows you to dump the contents of the microcontroller’s nonvolatile
memory to a tester or to a memory device (such as flash memory or RAM).
Chapter 16, “Programming the Nonvolatile Memory,” provides recommended circuits, the corre-
sponding memory maps, and flow diagrams. It also provides procedures for auto programming.
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3
Programming
Considerations
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CHAPTER 3
PROGRAMMING CONSIDERATIONS
®
This section provides an overview of the instruction set of the MCS 96 microcontrollers and of-
fers guidelines for program development. For detailed information about specific instructions,
see Appendix A.
3.1 OVERVIEW OF THE INSTRUCTION SET
The instruction set supports a variety of operand types likely to be useful in control applications
(see Table 3-1).
NOTE
The operand-type variables are shown in all capitals to avoid confusion. For
example, a BYTE is an unsigned 8-bit variable in an instruction, while a byte is
any 8-bit unit of data (either signed or unsigned).
Table 3-1. Operand Type Definitions
No. of
Bits
Addressing
Restrictions
Operand Type
BIT
Signed
Possible Values
1
8
8
No
No
True (1) or False (0)
As components of bytes
BYTE
0 through 28–1 (0 through 255)
None
None
SHORT-INTEGER
Yes
–27 through +27–1
(–128 through +127)
WORD
16
16
32
No
Yes
No
0 through 216–1
(0 through 65,535)
Even byte address
Even byte address
INTEGER
–215 through +215–1
(–32,768 through +32,767)
DOUBLE-WORD
(Note 1)
0 through 232–1
(0 through 4,294,967,295)
An address in the lower
register file that is evenly
divisible by four (Note 2)
LONG-INTEGER
(Note 1)
32
Yes
–231 through +231–1
(–2,147,483,648 through
+2,147,483,647)
An address in the lower
register file that is evenly
divisible by four (Note 2)
NOTES:
1. The 32-bit variables are supported only as the operand in shift operations, as the dividend in 32-by-
16 divide operations, and as the product of 16-by-16 multiply operations.
2. For consistency with third-party software, you should adopt the C programming conventions for
addressing 32-bit operands. For more information, refer to page 3-9.
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Table 3-2 lists the equivalent operand-type names for both C programming and assembly lan-
guage.
Table 3-2. Equivalent Operand Types for Assembly and C Programming Languages
Operand Types
Assembly Language Equivalent
C Programming Language Equivalent
BYTE
BYTE
BYTE
unsigned char
char
SHORT-INTEGER
WORD
WORD
WORD
LONG
LONG
unsigned int
int
INTEGER
DOUBLE-WORD
LONG-INTEGER
unsigned long
long
3.1.1 BIT Operands
A BIT is a single-bit variable that can have the Boolean values, “true” and “false.” The architec-
ture requires that BITs be addressed as components of BYTEs or WORDs. It does not support the
direct addressing of BITs.
3.1.2 BYTE Operands
8
A BYTE is an unsigned, 8-bit variable that can take on values from 0 through 255 (2 –1). Arith-
metic and relational operators can be applied to BYTE operands, but the result must be interpret-
ed in modulo 256 arithmetic. Logical operations on BYTEs are applied bitwise. Bits within
BYTEs are labeled from 0 to 7; bit 0 is the least-significant bit. There are no alignment restric-
tions for BYTEs, so they may be placed anywhere in the address space.
3.1.3 SHORT-INTEGER Operands
A SHORT-INTEGER is an 8-bit, signed variable that can take on values from –128 (–27) through
+127 (+27–1). Arithmetic operations that generate results outside the range of a SHORT-
INTEGER set the overflow flags in the processor status word (PSW). The numeric result is the
same as the result of the equivalent operation on BYTE variables. There are no alignment restric-
tions on SHORT-INTEGERs, so they may be placed anywhere in the address space.
3.1.4 WORD Operands
16
A WORD is an unsigned, 16-bit variable that can take on values from 0 through 65,535 (2 –1).
Arithmetic and relational operators can be applied to WORD operands, but the result must be in-
terpreted in modulo 65536 arithmetic. Logical operations on WORDs are applied bitwise. Bits
within WORDs are labeled from 0 to 15; bit 0 is the least-significant bit.
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PROGRAMMING CONSIDERATIONS
WORDs must be aligned at even byte boundaries in the address space. The least-significant byte
of the WORD is in the even byte address, and the most-significant byte is in the next higher (odd)
address. The address of a WORD is that of its least-significant byte (the even byte address).
WORD operations to odd addresses are not guaranteed to operate in a consistent manner.
3.1.5 INTEGER Operands
15
An INTEGER is a 16-bit, signed variable that can take on values from –32,768 (–2 ) through
15
+32,767 (+2 –1). Arithmetic operations that generate results outside the range of an INTEGER
set the overflow flags in the processor status word (PSW). The numeric result is the same as the
result of the equivalent operation on WORD variables.
INTEGERs must be aligned at even byte boundaries in the address space. The least-significant
byte of the INTEGER is in the even byte address, and the most-significant byte is in the next high-
er (odd) address. The address of an INTEGER is that of its least-significant byte (the even byte
address). INTEGER operations to odd addresses are not guaranteed to operate in a consistent
manner.
3.1.6 DOUBLE-WORD Operands
A DOUBLE-WORD is an unsigned, 32-bit variable that can take on values from 0 through
32
4,294,967,295 (2 –1). The architecture directly supports DOUBLE-WORD operands only as
the operand in shift operations, as the dividend in 32-by-16 divide operations, and as the product
of 16-by-16 multiply operations. For these operations, a DOUBLE-WORD variable must reside
in the lower register file and must be aligned at an address that is evenly divisible by four. The
address of a DOUBLE-WORD is that of its least-significant byte (the even byte address). The
least-significant word of the DOUBLE-WORD is always in the lower address, even when the
data is in the stack. This means that the most-significant word must be pushed into the stack first.
DOUBLE-WORD operations that are not directly supported can be easily implemented with two
WORD operations. For example, the following sequences of 16-bit operations perform a 32-bit
addition and a 32-bit subtraction, respectively.
ADD REG1,REG3
ADDC REG2,REG4
; (2-operand addition)
SUB REG1,REG3
SUBC REG2,REG4
; (2-operand subtraction)
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3.1.7 LONG-INTEGER Operands
A LONG-INTEGER is a 32-bit, signed variable that can take on values from –2,147,483,648
31
31
(– 2 ) through +2,147,483,647 (+2 –1). The architecture directly supports LONG-INTEGER
operands only as the operand in shift operations, as the dividend in 32-by-16 divide operations,
and as the product of 16-by-16 multiply operations. For these operations, a LONG-INTEGER
variable must reside in the lower register file and must be aligned at an address that is evenly di-
visible by four. The address of a LONG-INTEGER is that of its least-significant byte (the even
byte address).
LONG-INTEGER operations that are not directly supported can be easily implemented with two
INTEGER operations. See the example in “DOUBLE-WORD Operands” on page 3-3.
3.1.8 Converting Operands
The instruction set supports conversions between the operand types. The LDBZE (load byte, zero
extended) instruction converts a BYTE to a WORD. CLR (clear) converts a WORD to a
DOUBLE-WORD by clearing (writing zeros to) the upper WORD of the DOUBLE-WORD.
LDBSE (load byte, sign extended) converts a SHORT-INTEGER into an INTEGER. EXT (sign
extend) converts an INTEGER to a LONG-INTEGER.
3.1.9 Conditional Jumps
The instructions for addition, subtraction, and comparison do not distinguish between unsigned
(BYTE, WORD) and signed (SHORT-INTEGER, INTEGER) operands. However, the condition-
al jump instructions allow you to treat the results of these operations as signed or unsigned quan-
tities. For example, the CMP (compare) instruction is used to compare both signed and unsigned
16-bit quantities. Following a compare operation, you can use the JH (jump if higher) instruction
for unsigned operands or the JGT (jump if greater than) instruction for signed operands.
3.1.10 Floating Point Operations
The hardware does not directly support operations on REAL (floating point) variables. Those op-
erations are supported by floating point libraries from third-party tool vendors. (See the Develop-
ment Tools Handbook.) The performance of these operations is significantly improved by the
NORML instruction and by the sticky bit (ST) flag in the processor status word (PSW). The
NORML instruction normalizes a 32-bit variable; the sticky bit (ST) flag can be used in conjunc-
tion with the carry (C) flag to achieve finer resolution in rounding.
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PROGRAMMING CONSIDERATIONS
3.2 ADDRESSING MODES
The instruction set uses four basic addressing modes:
• direct
• immediate
• indirect (with or without autoincrement)
• indexed (short-, long-, or zero-indexed)
The stack pointer can be used with indirect addressing to access the top of the stack, and it can
also be used with short-indexed addressing to access data within the stack. The zero register can
be used with long-indexed addressing to access any memory location.
An instruction can contain only one immediate, indirect, or indexed reference; any remaining op-
erands must be direct references.
This section describes the addressing modes as they are handled by the hardware. An understand-
ing of these details will help programmers to take full advantage of the architecture. The assembly
language hides some of the details of how these addressing modes work. “Assembly Language
Addressing Mode Selections” on page 3-9 describes how the assembly language handles direct
and indexed addressing modes.
The examples in this section assume that temporary registers are defined as shown in this segment
of assembly code and described in Table 3-3.
Oseg at 1ch
AL:
BL:
CL:
DL:
AX:
BX:
CX:
DX:
DSB 1
DSB 1
DSB 1
DSB 1
DSW 1
DSW 1
DSW 1
DSW 1
THISVAR: DSW 1
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Table 3-3. Definition of Temporary Registers
Temporary Register
Description
AX
BX
CX
DX
word-aligned 16-bit register; AH is the high byte of AX and AL is the low byte
word-aligned 16-bit register; BH is the high byte of BX and BL is the low byte
word-aligned 16-bit register; CH is the high byte of CX and CL is the low byte
word-aligned 16-bit register; DH is the high byte of DX and DL is the low byte
3.2.1 Direct Addressing
Direct addressing directly accesses a location in the 256-byte lower register file, without involv-
ing the memory controller. Windowing allows you to remap other sections of memory into the
lower register file for direct access (see Chapter 4, “Memory Partitions,” for details). You specify
the registers as operands within the instruction. The register addresses must conform to the align-
ment rules for the operand type. Depending on the instruction, up to three registers can take part
in a calculation. The following instructions use direct addressing:
ADD AX,BX,CX
ADDB AL,BL,CL
MULB AX,BL
INCB CL
; AX ← BX + CX
; AL ← BL + CL
; AX ← AX × BL
; CL ← CL + 1
3.2.2 Immediate Addressing
Immediate addressing mode accepts one immediate value as an operand in the instruction. You
specify an immediate value by preceding it with a number symbol (#). An instruction can contain
only one immediate value; the remaining operands must be direct references. The following in-
structions use immediate addressing:
ADD AX,#340
PUSH #1234H
; AX ← AX + 340
; SP ← SP - 2
; MEM_WORD(SP) ← 1234H
; AL ← AX/10
DIVB AX,#10
; AH ← AX MOD 10
3.2.3 Indirect Addressing
The indirect addressing mode accesses an operand by obtaining its address from a WORD regis-
ter in the lower register file. You specify the register containing the indirect address by enclosing
it in square brackets ([ ]). The indirect address can refer to any location within the address space,
including the register file. The register that contains the indirect address must be word-aligned,
and the indirect address must conform to the rules for the operand type. An instruction can contain
only one indirect reference; any remaining operands must be direct references. The following in-
structions use indirect addressing:
LD
AX,[BX]
; AX ← MEM_WORD(BX)
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PROGRAMMING CONSIDERATIONS
ADDB AL,BL,[CX]
POP [AX]
; AL ← BL + MEM_BYTE(CX)
; MEM_WORD(AX) ← MEM_WORD(SP)
; SP ← SP + 2
3.2.3.1
Indirect Addressing with Autoincrement
You can choose to automatically increment the indirect address after the current access. You spec-
ify autoincrementing by adding a plus sign (+) to the end of the indirect reference. In this case,
the instruction automatically increments the indirect address (by one if the destination is an 8-bit
register or by two if it is a 16-bit register). When your code is assembled, the assembler automat-
ically sets the least-significant bit of the indirect address register. The following instructions use
indirect addressing with autoincrement:
LD
AX,[BX]+
; AX ← MEM_WORD(BX)
; BX ← BX + 2
ADDB AL,BL,[CX]+
PUSH [AX]+
; AL ← BL + MEM_BYTE(CX)
; CX ← CX + 1
; SP ← SP - 2
; MEM_WORD(SP) ← MEM_WORD(AX)
; AX ← AX + 2
3.2.3.2
Indirect Addressing with the Stack Pointer
You can also use indirect addressing to access the top of the stack by using the stack pointer as
the WORD register in an indirect reference. The following instruction uses indirect addressing
with the stack pointer:
PUSH [SP]
; duplicate top of stack
; SP ← SP + 2
3.2.4 Indexed Addressing
Indexed addressing calculates an address by adding an offset to a base address. There are three
variations of indexed addressing: short-indexed, long-indexed, and zero-indexed. Both short- and
long-indexed addressing are used to access a specific element within a structure. Short-indexed
addressing can access up to 255 byte locations, long-indexed addressing can access up to 65,535
byte locations, and zero-indexed addressing can access a single location. An instruction can con-
tain only one indexed reference; any remaining operands must be direct references.
3.2.4.1
Short-indexed Addressing
In a short-indexed instruction, you specify the offset as an 8-bit constant and the base address as
an indirect address register (a WORD). The following instructions use short-indexed addressing.
LD
AX,12H[BX]
; AX ← MEM_WORD(BX + 12H)
×
MULB AX,BL,3[CX]
; AX ← BL MEM_BYTE(CX + 3)
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The instruction LD AX,12H[BX] loads AX with the contents of the memory location that resides
at address BX+12H. That is, the instruction adds the constant 12H (the offset) to the contents of
BX (the base address), then loads AX with the contents of the resulting address. For example, if
BX contains 1000H, then AX is loaded with the contents of location 1012H. Short-indexed ad-
dressing is typically used to access elements in a structure, where BX contains the base address
of the structure and the constant (12H in this example) is the offset of a specific element in a struc-
ture.
You can also use the stack pointer in a short-indexed instruction to access a particular location
within the stack, as shown in the following instruction.
LD
AX,2[SP]
3.2.4.2
Long-indexed Addressing
In a long-indexed instruction, you specify the base address as a 16-bit variable and the offset as
an indirect address register (a WORD). The following instructions use long-indexed addressing.
LD
AND AX,BX,TABLE[CX]
ST AX,TABLE[BX]
ADDB AL,BL,LOOKUP[CX]
AX,TABLE[BX]
; AX ← MEM_WORD(TABLE + BX)
; AX ← BX AND MEM_WORD(TABLE + CX)
; MEM_WORD(TABLE + BX) ← AX
; AL ← BL + MEM_BYTE(LOOKUP + CX)
The instruction LD AX, TABLE[BX] loads AX with the contents of the memory location that re-
sides at address TABLE+BX. That is, the instruction adds the contents of BX (the offset) to the
constant TABLE (the base address), then loads AX with the contents of the resulting address. For
example, if TABLE equals 4000H and BX contains 12H, then AX is loaded with the contents of
location 4012H. Long-indexed addressing is typically used to access elements in a table, where
TABLE is a constant that is the base address of the structure and BX is the scaled offset (n × el-
ement size, in bytes) into the structure.
3.2.4.3
Zero-indexed Addressing
In a zero-indexed instruction, you specify the address as a 16-bit variable; the offset is zero, and
you can express it in one of three ways: [0], [ZERO_REG], or nothing. Each of the following load
instructions loads AX with the contents of the variable THISVAR.
LD
LD
LD
AX,THISVAR[0]
AX,THISVAR[ZERO_REG]
AX,THISVAR
The following instructions also use zero-indexed addressing:
ADD AX,1234H[ZERO_REG]
POP 5678H[ZERO_REG]
; AX ← AX + MEM_WORD(1234H)
; MEM_WORD(5678H) ← MEM_WORD(SP)
; SP ← SP + 2
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PROGRAMMING CONSIDERATIONS
3.3 ASSEMBLY LANGUAGE ADDRESSING MODE SELECTIONS
The assembly language simplifies the choice of addressing modes. Use these features wherever
possible.
3.3.1 Direct Addressing
The assembly language chooses between direct and zero-indexed addressing depending on the
memory location of the operand. Simply refer to the operand by its symbolic name. If the operand
is in the lower register file, the assembly language chooses a direct reference. If the operand is
elsewhere in memory, it chooses a zero-indexed reference.
3.3.2 Indexed Addressing
The assembly language chooses between short-indexed and long-indexed addressing depending
on the value of the index expression. If the value can be expressed in eight bits, the assembly lan-
guage chooses a short-indexed reference. If the value is greater than eight bits, it chooses a long-
indexed reference.
3.4 SOFTWARE STANDARDS AND CONVENTIONS
For a software project of any size, it is a good idea to develop the program in modules and to es-
tablish standards that control communication between the modules. These standards vary with the
needs of the final application. However, all standards must include some mechanism for passing
parameters to procedures and returning results from procedures. We recommend that you use the
conventions adopted by the C programming language for procedure linkage. These standards are
usable for both the assembly language and C programming environments, and they offer compat-
ibility between these environments.
3.4.1 Using Registers
The 256-byte lower register file contains the CPU special-function registers and the stack pointer.
The remainder of the lower register file and all of the upper register file is available for your use.
Peripheral special-function registers (SFRs) and memory-mapped SFRs reside in higher memory.
The peripheral SFRs can be windowed into the lower register file for direct access. Memory-
mapped SFRs cannot be windowed; you must use indirect or indexed addressing to access them.
All SFRs can be operated on as BYTEs or WORDs, unless otherwise specified. See “Special-
function Registers (SFRs)” on page 4-4 and “Register File” on page 4-9 for more information.
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To use these registers effectively, you must have some overall strategy for allocating them. The
C programming language adopts a simple, effective strategy. It allocates the eight bytes beginning
at address 1CH as temporary storage and treats the remaining area in the register file as a segment
of memory that is allocated as required.
NOTE
Using any SFR as a base or index register for indirect or indexed operations
can cause unpredictable results because external events can change the
contents of SFRs. Also, because some SFRs are cleared when read, consider
the implications of using an SFR as an operand in a read-modify-write
instruction (e.g., XORB).
3.4.2 Addressing 32-bit Operands
The 32-bit operands (DOUBLE-WORDs and LONG-INTEGERs) are formed by two adjacent
16-bit words in memory. The least-significant word of a DOUBLE-WORD is always in the lower
address, even when the data is in the stack (which means that the most-significant word must be
pushed into the stack first). The address of a 32-bit operand is that of its least-significant byte.
The hardware supports the 32-bit data types as operands in shift operations, as dividends of 32-
by-16 divide operations, and as products of 16-by-16 multiply operations. For these operations,
the 32-bit operand must reside in the lower register file and must be aligned at an address that is
evenly divisible by four.
3.4.3 Linking Subroutines
Parameters are passed to subroutines via the stack. Parameters are pushed into the stack from the
rightmost parameter to the left. The 8-bit parameters are pushed into the stack with the high-order
byte undefined. The 32-bit parameters are pushed into the stack as two 16-bit values; the most-
significant half of the parameter is pushed into the stack first. As an example, consider the fol-
lowing procedure:
void example_procedure (char param1, long param2, int param3);
When this procedure executes at run-time, the stack will contain the parameters in the following
order:
param3
low word of param2
high word of param2
undefined;param1
return address
← Stack Pointer
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PROGRAMMING CONSIDERATIONS
If a procedure returns a value to the calling code (as opposed to modifying more global variables),
the result is returned in the temporary storage space (TMPREG0, in this example) starting at 1CH.
TMPREG0 is viewed as either an 8-, 16-, or 32bit variable, depending on the type of the proce-
dure.
The standard calling convention adopted by the C programming language has several key fea-
tures:
• Procedures can always assume that the eight bytes of register file memory starting at 1CH
can be used as temporary storage within the body of the procedure.
• Code that calls a procedure must assume that the procedure modifies the eight bytes of
register file memory starting at 1CH.
• Code that calls a procedure must assume that the procedure modifies the processor status
word (PSW) condition flags because procedures do not save and restore the PSW.
• Function results from procedures are always returned in the variable TMPREG0.
The C programming language allows the definition of interrupt procedures, which are executed
when a predefined interrupt request occurs. Interrupt procedures do not conform to the rules of
normal procedures. Parameters cannot be passed to these procedures and they cannot return re-
sults. Since interrupt procedures can execute essentially at any time, they must save and restore
both the PSW and TMPREG0.
3.5 SOFTWARE PROTECTION FEATURES AND GUIDELINES
The device has several features to assist in recovering from hardware and software errors. The
unimplemented opcode interrupt provides protection from executing unimplemented opcodes.
The hardware reset instruction (RST) can cause a reset if the program counter goes out of bounds.
The RST instruction opcode is FFH, so the processor will reset itself if it tries to fetch an instruc-
tion from unprogrammed locations in nonvolatile memory or from bus lines that have been pulled
high. The watchdog timer (WDT) can also reset the device in the event of a hardware or software
error.
We recommend that you fill unused areas of code with NOPs and periodic jumps to an error rou-
tine or RST instruction. This is particularly important in the code surrounding lookup tables, since
accidentally executing from lookup tables will cause undesired results. Wherever space allows,
surround each table with seven NOPs (because the longest device instruction has seven bytes) and
a RST or a jump to an error routine. Since RST is a one-byte instruction, the NOPs are unneces-
sary if RSTs are used instead of jumps to an error routine. This will help to ensure a speedy re-
covery from a software error.
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When using the watchdog timer (WDT) for software protection, we recommend that you reset the
WDT from only one place in code, reducing the chance of an undesired WDT reset. The section
of code that resets the WDT should monitor the other code sections for proper operation. This can
be done by checking variables to make sure they are within reasonable values. Simply using a
software timer to reset the WDT every 10 milliseconds will provide protection only for cata-
strophic failures.
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4
Memory
Partitions
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CHAPTER 4
MEMORY PARTITIONS
This chapter describes the address space, its major partitions, and a windowing technique for ac-
cessing the upper register file and peripheral SFRs with register-direct instructions.
4.1 MEMORY PARTITIONS
Table 4-1 is a memory map of the 8XC196Mx devices. The remainder of this section describes
the partitions.
4.1.1 External Devices (Memory or I/O)
Several partitions are assigned to external devices (see Table 4-1). Data can be stored in any part
of this memory. Chapter 15, “Interfacing with External Memory,” describes the external memory
interface and shows examples of external memory configurations. These partitions can also be
used to interface with external peripherals connected to the address/data bus.
4.1.2 Program and Special-purpose Memory
Internal nonvolatile memory is an optional component of the 8XC196Mx devices. Various devic-
es are available with masked ROM, EPROM, QROM, or OTPROM. Please consult the
datasheets in the Embedded Microcontrollers databook for details.
If present, the nonvolatile memory occupies the special-purpose memory and program memory
partitions (locations 2000H and above; see Table 4-1 on page 4-2). The EA# signal controls ac-
cess to these memory partitions. Accesses to these partitions are directed to internal memory if
EA# is held high and to external memory if EA# is held low. For devices without internal non-
volatile memory, the EA# signal must be tied low. EA# is latched at reset.
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Table 4-1. Memory Map
Device and
Hex Address
Range
Description
Addressing Modes
MC, MD
MH
FFFF
6000
FFFF External device (memory or I/O) connected to the
A000 address/data bus
Indirect or indexed
Indirect or indexed
Indirect or indexed
Indirect or indexed
5FFF
2080
9FFF Program memory (internal nonvolatile or external
2080 memory); see Note 1.
207F
2000
207F Special-purpose memory (internal nonvolatile or
2000 external memory)
1FFF
1FE0
1FFF
Memory-mapped SFRs
1FE0
1FDF
1F00
1FDF
Indirect, indexed, or
windowed direct
Peripheral SFRs
1F00
1EFF
0200
1EFF External device (memory or I/O) connected to the
0300 address/data bus (future SFR expansion; see Note 2)
Indirect or indexed
01FF
0100
02FF
Indirect, indexed, or
windowed direct
Upper register file (general-purpose register RAM)
0100
00FF
0000
00FF Lower register file (general-purpose register RAM,
0000 stack pointer, and CPU SFRs)
Direct, indirect, or indexed
NOTES:
1. After a reset, the device fetches its first instruction from 2080H.
2. The content or function of these locations may change in future device revisions, in which case a pro-
gram that relies on a location in this range might not function properly.
4.1.3 Program Memory
Program memory occupies a memory partition beginning at 2080H. (See Table 4-1 for the ending
address for each device.) This entire partition is available for storing executable code and data.
The EA# signal controls access to program memory. Accesses to this address range are directed
to internal memory if EA# is held high and to external memory if EA# is held low. For devices
without internal nonvolatile memory, the EA# signal must be tied low. EA# is latched at reset.
NOTE
We recommend that you write FFH (the opcode for the RST instruction) to
unused program memory locations. This causes a device reset if a program
unintentionally begins to execute in unused memory.
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MEMORY PARTITIONS
4.1.4 Special-purpose Memory
Special-purpose memory resides in locations 2000–207FH (Table 4-2). It contains several re-
served memory locations, the chip configuration bytes (CCBs), and vectors for both peripheral
transaction server (PTS) and standard interrupts. Accesses to this address range are directed to
internal memory if EA# is held high and to external memory if EA# is held low. For devices with-
out internal nonvolatile memory, the EA# signal must be tied low. EA# is latched at reset.
Table 4-2. Special-purpose Memory Addresses
Hex Address
Description
207F
205E
Reserved (each byte must contain FFH)
205D
2040
PTS vectors
203F
2030
Upper interrupt vectors
Security key
202F
2020
201F
201E
201D
201C
201B
201A
2019
2018
Reserved (must contain 20H)
Reserved (must contain FFH)
Reserved (must contain 20H)
Reserved (must contain FFH)
Reserved (must contain 20H)
CCB1
Reserved (must contain 20H)
CCB0
2017
2014
Reserved (each byte must contain FFH)
Lower interrupt vectors
2013
2000
4.1.4.1
Reserved Memory Locations
Several memory locations are reserved for testing or for use in future products. Do not read or
write these locations except to initialize them. The function or contents of these locations may
change in future revisions; software that uses reserved locations may not function properly. Al-
ways initialize reserved locations to the values listed in Table 4-2.
4.1.4.2
Interrupt and PTS Vectors
The upper and lower interrupt vectors contain the addresses of the interrupt service routines. The
peripheral transaction server (PTS) vectors contain the addresses of the PTS control blocks. See
Chapter 5, “Standard and PTS Interrupts,” for more information on interrupt and PTS vectors.
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4.1.4.3
Security Key
The security key prevents unauthorized programming access to the nonvolatile memory. See
Chapter 16, “Programming the Nonvolatile Memory,” for details.
4.1.4.4
Chip Configuration Bytes (CCBs)
The chip configuration bytes (CCBs) specify the operating environment. They specify the bus
width, bus-control mode, and wait states. They also control powerdown mode, the watchdog tim-
er, and nonvolatile memory protection.
The CCBs are the first bytes fetched from memory when the device leaves the reset state. The
post-reset sequence loads the CCBs into the chip configuration registers (CCRs). Once they are
loaded, the CCRs cannot be changed until the next device reset. Typically, the CCBs are pro-
grammed once when the user program is compiled and are not redefined during normal operation.
“Chip Configuration Registers and Chip Configuration Bytes” on page 15-5 describes the CCBs
and CCRs.
For devices with customer-programmable nonvolatile memory, the CCBs are loaded for normal
operation, but the PCCBs are loaded into the CCRs if the device is entering programming modes.
See Chapter 16, “Programming the Nonvolatile Memory,” for details.
4.1.5 Special-function Registers (SFRs)
These devices have both memory-mapped SFRs and peripheral SFRs. The memory-mapped
SFRs must be accessed using indirect or indexed addressing modes, and they cannot be win-
dowed. The peripheral SFRs are physically located in the on-chip peripherals, and they can be
windowed (see “Windowing” on page 4-12). Do not use reserved SFRs; write zeros to them or
leave them in their default state. When read, reserved bits and reserved SFRs return undefined
values.
NOTE
Using any SFR as a base or index register for indirect or indexed operations
can cause unpredictable results because external events can change the
contents of SFRs. Also, because some SFRs are cleared when read, consider
the implications of using an SFR as an operand in a read-modify-write
instruction (e.g., XORB).
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MEMORY PARTITIONS
4.1.5.1
Memory-mapped SFRs
Locations 1FE0–1FFFH contain memory-mapped SFRs (see Table 4-3). Locations in this range
that are omitted from the table are reserved. The memory-mapped SFRs must be accessed with
indirect or indexed addressing modes, and they cannot be windowed. If you read a location in this
range through a window, the SFR appears to contain FFH (all ones). If you write a location in
this range through a window, the write operation has no effect on the SFR.
The memory-mapped SFRs are accessed through the memory controller, so instructions that op-
erate on these SFRs execute as they would from external memory with zero wait states.
Table 4-3. Memory-mapped SFRs
Ports 3, 4, 5, UPROM SFRs
Hex Address High (Odd) Byte Low (Even) Byte
1FFE
1FFC
• • •
P4_PIN
P4_REG
• • •
P3_PIN
P3_REG
• • •
1FF6
1FF4
1FF2
1FF0
P5_PIN
P5_REG
P5_DIR
P5_MODE
USFR
Reserved
Reserved
Reserved
4.1.5.2
Peripheral SFRs
Locations 1F00–1FDFH provide access to the peripheral SFRs. Table 4-6 on page 4-8, Table 4-6
on page 4-8, and Table 4-6 on page 4-8 list the peripheral SFRs of the 8XC196MC, 8XC196MD,
and 8XC196MH, respectively. Locations that are omitted from the tables are reserved. The pe-
ripheral SFRs are I/O control registers; they are physically located in the on-chip peripherals.
These peripheral SFRs can be windowed and they can be addressed either as words or bytes, ex-
cept as noted in the tables.
The peripheral SFRs are accessed directly, without using the memory controller, so instructions
that operate on these SFRs execute as they would if they were operating on the register file.
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Table 4-4. Peripheral SFRs — 8XC196MC
Port 2 SFRs EPA and Timer SFRs
High (Odd) Byte High (Odd) Byte Low (Even) Byte
1FDEH Reserved
Address
Low (Even) Byte
Reserved
• • •
Address
†1F7EH TIMER2 (H)
1F7CH Reserved
†1F7AH TIMER1 (H)
1F78H Reserved
1F76H Reserved
1F74H Reserved
1F72H T1RELOAD (H)
1F70H Reserved
TIMER2 (L)
T2CONTROL
TIMER1 (L)
T1CONTROL
Reserved
• • •
• • •
1FD6H Reserved
1FD4H Reserved
1FD2H Reserved
1FD0H Reserved
P2_PIN
P2_REG
P2_DIR
P2_MODE
Reserved
Waveform Generator SFRs
High (Odd) Byte Low (Even) Byte
1FCEH Reserved WG_PROTECT
T1RELOAD (L)
Reserved
Address
• • •
• • •
• • •
1FCCH WG_CONTROL(H) WG_CONTROL(L)
1FCAH WG_COUNTER(H) WG_COUNTER(L)
†1F66H COMP3_TIME (H) COMP3_TIME (L)
1F64H Reserved COMP3_CON
†1F62H COMP2_TIME (H) COMP2_TIME (L)
1F60H Reserved COMP2_CON
†1F5EH COMP1_TIME (H) COMP1_TIME (L)
1F5CH Reserved COMP1_CON
†1F5AH COMP0_TIME (H) COMP0_TIME (L)
1FC8H WG_RELOAD (H)
1FC6H WG_COMP3 (H)
1FC4H WG_COMP2 (H)
1FC2H WG_COMP1 (H)
1FC0H WG_OUTPUT (H)
WG_RELOAD (L)
WG_COMP3 (L)
WG_COMP2 (L)
WG_COMP1 (L)
WG_OUTPUT (L)
Peripheral Interrupt and PWM SFRs
Address High (Odd) Byte Low (Even) Byte
1FBEH Reserved
1FBCH Reserved
1F58H Reserved
1F56H Reserved
COMP0_CON
Reserved
PI_PEND
PI_MASK
• • •
• • •
• • •
†1F4EH EPA3_TIME (H)
1F4CH Reserved
†1F4AH EPA2_TIME (H)
1F48H Reserved
†1F46H EPA1_TIME (H)
1F44H Reserved
†1F42H EPA0_TIME (H)
1F40H Reserved
EPA3_TIME (L)
EPA3_CON
EPA2_TIME (L)
EPA2_CON
EPA1_TIME (L)
EPA1_CON
EPA0_TIME (L)
EPA0_CON
• • •
• • •
• • •
1FB6H Reserved
1FB4H Reserved
1FB2H Reserved
1FB0H Reserved
PWM_COUNT
PWM_PERIOD
PWM1_CONTROL
PWM0_CONTROL
A/D SFRs
High (Odd) Byte
Address
Low (Even) Byte
AD_TEST
1FAEH AD_TIME
1FACH Reserved
AD_COMMAND
AD_RESULT (L)
P0_PIN
1FAAH AD_RESULT (H)
1FA8H P1_PIN
1FA6H Reserved
Reserved
• • •
• • •
• • •
1F80H Reserved
Reserved
† Must be addressed as a word.
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MEMORY PARTITIONS
Table 4-5. Peripheral SFRs — 8XC196MD
Ports 2 and 7 SFRs EPA and Timer SFRs
High (Odd) Byte
Address
Low (Even) Byte
Reserved
Reserved
Reserved
Reserved
P2_PIN
Address
High (Odd) Byte
Low (Even) Byte
TIMER2 (L)
1FDEH Reserved
1FDCH Reserved
1FDAH Reserved
1FD8H Reserved
1FD6H P7_PIN
1FD4H P7_REG
1FD2H P7_DIR
1FD0H P7_MODE
†1F7EH TIMER2 (H)
1F7CH Reserved
T2CONTROL
TIMER1 (L)
†1F7AH TIMER1 (H)
1F78H Reserved
T1CONTROL
Reserved
1F76H Reserved
P2_REG
1F74H Reserved
Reserved
P2_DIR
1F72H T1RELOAD (H)
T1RELOAD (L)
Reserved
P2_MODE
1F70H Reserved
Waveform Generator SFRs
†1F6EH COMP5_TIME (H)
1F6CH Reserved
†1F6AH COMP4_TIME (H)
COMP5_TIME (L)
COMP5_CON
COMP4_TIME (L)
COMP4_CON
COMP3_TIME (L)
COMP3_CON
COMP2_TIME (L)
COMP2_CON
COMP1_TIME (L)
COMP1_CON
COMP0_TIME (L)
COMP0_CON
EPA5_TIME (L)
EPA5_CON
Address
High (Odd) Byte
Low (Even) Byte
1FCEH Reserved
WG_PROTECT
1FCCH WG_CONTROL(H) WG_CONTROL(L)
1FCAH WG_COUNTER(H) WG_COUNTER(L)
1F68H Reserved
†1F66H COMP3_TIME (H)
1F64H Reserved
†1F62H COMP2_TIME (H)
1FC8H WG_RELOAD (H)
1FC6H WG_COMP3 (H)
1FC4H WG_COMP2 (H)
1FC2H WG_COMP1 (H)
1FC0H WG_OUTPUT (H)
WG_RELOAD (L)
WG_COMP3 (L)
WG_COMP2 (L)
WG_COMP1 (L)
WG_OUTPUT (L)
1F60H Reserved
†1F5EH COMP1_TIME (H)
1F5CH Reserved
†1F5AH COMP0_TIME (H)
Periph. Int., Freq. Gen., and PWM SFRs
Address
High (Odd) Byte
Low (Even) Byte
PI_PEND
1F58H Reserved
1FBEH Reserved
1FBCH Reserved
1FBAH Reserved
1FB8H Reserved
1FB6H Reserved
1FB4H Reserved
1FB2H Reserved
1FB0H Reserved
†1F56H EPA5_TIME (H)
1F54H Reserved
†1F52H EPA4_TIME (H)
PI_MASK
FREQ_CNT
EPA4_TIME (L)
EPA4_CON
FREQ_GEN
1F50H Reserved
PWM_COUNT
PWM_PERIOD
PWM1_CONTROL
PWM0_CONTROL
†1F4EH EPA3_TIME (H)
1F4CH Reserved
†1F4AH EPA2_TIME (H)
EPA3_TIME (L)
EPA3_CON
EPA2_TIME (L)
EPA2_CON
1F48H Reserved
A/D SFRs
High (Odd) Byte
†1F46H EPA1_TIME (H)
1F44H Reserved
†1F42H EPA0_TIME (H)
EPA1_TIME (L)
EPA1_CON
Address
Low (Even) Byte
AD_TEST
1FAEH AD_TIME
1FACH Reserved
EPA0_TIME (L)
EPA0_CON
AD_COMMAND
AD_RESULT (L)
P0_PIN
1F40H Reserved
1FAAH AD_RESULT (H)
1FA8H P1_PIN
• • •
• • •
• • •
1F80H Reserved
Reserved
† Must be addressed as a word.
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Table 4-6. Peripheral SFRs — 8XC196MH
Port 0 and 2 SFRs Port 1 SFRs
High (Odd) Byte High (Odd) Byte
1F9EH P1_PIN
Address
Low (Even) Byte
Reserved
Reserved
P0_PIN
Address
Low (Even) Byte
Reserved
Reserved
Reserved
Reserved
• • •
1FDEH Reserved
1FDCH Reserved
1FDAH Reserved
1FD8H Reserved
1FD6H Reserved
1FD4H Reserved
1FD2H Reserved
1FD0H Reserved
1F9CH P1_REG
1F9AH P1_DIR
1F98H P1_MODE
Reserved
P2_PIN
• • •
• • •
Serial I/O Port SFRs
High (Odd) Byte Low (Even) Byte
P2_REG
P2_DIR
Address
P2_MODE
1F8EH Reserved
Reserved
Waveform Generator SFRs
1F8CH SP1_BAUD(H)
1F8AH SP1_CON
1F88H SP1_STATUS
1F86H Reserved
SP1_BAUD (L)
SBUF1_TX
SBUF1_RX
Reserved
Address
High (Odd) Byte
Low (Even) Byte
1FCEH Reserved
WG_PROTECT
1FCCH WG_CONTROL(H) WG_CONTROL (L)
1FCAH WG_COUNTER(H) WG_COUNTER (L)
1F84H SP0_BAUD (H)
1F82H SP0_CON
1F80H SP0_STATUS
SP0_BAUD (L)
SBUF0_TX
SBUF0_RX
1FC8H WG_RELOAD (H)
1FC6H WG_COMP3 (H)
1FC4H WG_COMP2 (H)
1FC2H WG_COMP1 (H)
1FC0H WG_OUTPUT (H)
WG_RELOAD (L)
WG_COMP3 (L)
WG_COMP2 (L)
WG_COMP1 (L)
WG_OUTPUT (L)
EPA and Timer SFRs
High (Odd) Byte
Address
Low (Even) Byte
TIMER2 (L)
T2CONTROL
TIMER1 (L)
T1CONTROL
• • •
†1F7EH TIMER2 (H)
1F7CH Reserved
†1F7AH TIMER1 (H)
1F78H Reserved
Peripheral Interrupt and PWM SFRs
Address High (Odd) Byte Low (Even) Byte
1FBEH Reserved
PI_PEND
1FBCH Reserved
1FBAH Reserved
1FB8H Reserved
1FB6H Reserved
1FB4H Reserved
1FB2H Reserved
1FB0H Reserved
PI_MASK
• • •
1F72H T1RELOAD (H)
• • • • • •
• • •
Reserved
T1RELOAD (L)
• • •
Reserved
PWM_COUNT
PWM_PERIOD
PWM1_CONTROL
PWM0_CONTROL
†1F62H COMP2_TIME(H) COMP2_TIME(L)
1F60H Reserved COMP2_CON
†1F5EH COMP1_TIME(H) COMP1_TIME(L)
1F5CH Reserved COMP1_CON
†1F5AH COMP0_TIME(H) COMP0_TIME(L)
A/D SFRs
High (Odd) Byte
Address
Low (Even) Byte
AD_TEST
1F58H Reserved
• • • • • •
†1F4EH COMP3_TIME(H) COMP3_TIME(L)
COMP0_CON
• • •
1FAEH AD_TIME
1FACH Reserved
AD_COMMAND
AD_RESULT (L)
1FAAH AD_RESULT (H)
1F4CH Reserved
COMP3_CON
• • •
Reset Control SFR
High (Odd) Byte
1FA8H Reserved
• • •
• • •
Address
Low (Even) Byte
Reserved
• • •
†1F46H EPA1_TIME (H)
1F44H Reserved
†1F42H EPA0_TIME (H)
1F40H Reserved
EPA1_TIME (L)
EPA1_CON
EPA0_TIME (L)
EPA0_CON
• • •
• • •
1FA0H Reserved
† Must be addressed as a word.
GEN_CON
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MEMORY PARTITIONS
4.1.6 Register File
The register file (Figure 4-1) is divided into an upper register file and a lower register file. The
upper register file consists of general-purpose register RAM. The lower register file contains gen-
eral-purpose register RAM along with the stack pointer (SP) and the CPU special-function regis-
ters (SFRs).
Table 4-1 on page 4-2 lists the register file memory addresses. The RALU accesses the lower reg-
ister file directly, without the use of the memory controller. It also accesses a windowed location
directly (see “Windowing” on page 4-12). The upper register file and the peripheral SFRs can be
windowed. Registers in the lower register file and registers being windowed can be accessed with
register-direct addressing.
NOTE
The register file must not contain code. An attempt to execute an instruction
from a location in the register file causes the memory controller to fetch the
instruction from external memory.
Address
02FFH (MH)
General-purpose
Register RAM
0200H
01FFH (MC, MD)
Address
0100H
00FFH
02FFH
General-purpose
Register RAM
Upper
Register File
001AH
0019H
0018H
0017H
0000H
0100H
00FFH
Stack Pointer
CPU SFRs
Lower
Register File
0000H
A3066-02
Figure 4-1. Register File Memory Map
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Table 4-7. Register File Memory Addresses
Device and Hex
Address Range
Description
Addressing Modes
MC, MD
MH
01FF
0100
02FF
0100
Upper register file (register RAM)
Lower register file (register RAM)
Lower register file (stack pointer)
Lower register file (CPU SFRs)
Indirect, indexed, or windowed direct
Direct, indirect, or indexed
Direct, indirect, or indexed
Direct, indirect, or indexed
00FF
001A
00FF
001A
0019
0018
0019
0018
0017
0000
0017
0000
4.1.6.1
General-purpose Register RAM
The lower register file contains general-purpose register RAM. The stack pointer locations can
also be used as general-purpose register RAM when stack operations are not being performed.
The RALU can access this memory directly, using register-direct addressing.
The upper register file also contains general-purpose register RAM. The RALU normally uses
indirect or indexed addressing to access the RAM in the upper register file. Windowing enables
the RALU to use register-direct addressing to access this memory. (See Chapter 3, “Programming
Considerations,” for a discussion of addressing modes.) Windowing can provide for fast context
switching of interrupt tasks and faster program execution. (See “Windowing” on page 4-12.) PTS
control blocks and the stack are most efficient when located in the upper register file.
4.1.6.2
Stack Pointer (SP)
Memory locations 0018H and 0019H contain the stack pointer (SP). The SP contains the address
of the stack. The SP must point to a word (even) address that is two bytes greater than the desired
starting address. Before the CPU executes a subroutine call or interrupt service routine, it decre-
ments the SP by two and copies (PUSHes) the address of the next instruction from the program
counter onto the stack. It then loads the address of the subroutine or interrupt service routine into
the program counter. When it executes the return-from-subroutine (RET) instruction at the end of
the subroutine or interrupt service routine, the CPU loads (POPs) the contents of the top of the
stack (that is, the return address) into the program counter and increments the SP by two.
Subroutines may be nested. That is, each subroutine may call other subroutines. The CPU pushes
the contents of the program counter onto the stack each time it executes a subroutine call. The
stack grows downward as entries are added. The only limit to the nesting depth is the amount of
available memory. As the CPU returns from each nested subroutine, it pops the address off the
top of the stack, and the next return address moves to the top of the stack.
4-10
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Your program must load a word-aligned (even) address into the stack pointer. Select an address
that is two bytes greater than the desired starting address because the CPU automatically decre-
ments the stack pointer before it pushes the first byte of the return address onto the stack. Remem-
ber that the stack grows downward, so allow sufficient room for the maximum number of stack
entries. The stack must be located in either the internal register file or external RAM. The stack
can be used most efficiently when it is located in the register file.
The following example initializes the top of the upper register file (8XC196MC, MD) as the
stack. (For the 8XC196MH, the immediate value would be #300H.)
LD
SP, #200H
;Load stack pointer
The following example shows how to allow the linker locator to determine where the stack fits
in the memory map that you specify.
LD
SP, #STACK
4.1.6.3
CPU Special-function Registers (SFRs)
Locations 0000–0017H in the lower register file are the CPU SFRs (Table 4-8). Appendix C de-
scribes the CPU SFRs.
Table 4-8. CPU SFRs
Address High (Odd) Byte Low (Even) Byte
0016H
0014H
0012H
0010H
000EH
000CH
000AH
0008H
0006H
0004H
0002H
0000H
Reserved
Reserved
Reserved
WSR
INT_MASK1
Reserved
INT_PEND1
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
WATCHDOG
INT_MASK
PTSSRV (L)
PTSSEL (L)
ONES_REG (L)
ZERO_REG (L)
INT_PEND
PTSSRV (H)
PTSSEL (H)
ONES_REG (H)
ZERO_REG (H)
NOTE
Using any SFR as a base or index register for indirect or indexed operations
can cause unpredictable results because external events can change the
contents of SFRs. Also, because some SFRs are cleared when read, consider
the implications of using an SFR as an operand in a read-modify-write
instruction (e.g., XORB).
4-11
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4.2 WINDOWING
Windowing expands the amount of memory that is accessible with register-direct addressing.
Register-direct addressing can access the lower register file with short, fast-executing instruc-
tions. With windowing, register-direct addressing can also access the upper register file and pe-
ripheral SFRs.
Windowing maps a segment of higher memory (the upper register file or peripheral SFRs) into
the lower register file. The window selection register (WSR) selects a 32-, 64-, or 128-byte seg-
ment of higher memory to be windowed into the top of the lower register file space. Figure 4-2
illustrates a 128-byte window.
02FFH
01FFH
128-byte Window
(WSR = 13H)
128-byte Window
(WSR = 13H)
0180H
00FFH
0080H
WSR Window in
Lower Register File
WSR Window in
Lower Register File
0000H
8XC196MC,MD
8XC196MH
A3062-01
Figure 4-2. Windowing
NOTE
Memory-mapped SFRs must be accessed using indirect or indexed addressing
modes; they cannot be accessed through a window. Reading a memory-
mapped SFR through a window returns FFH (all ones), and writing to a
memory-mapped SFR through a window has no effect.
4-12
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4.2.1 Selecting a Window
The window selection register (Figure 4-3) selects a window to be mapped into the top of the low-
er register file.
Table 4-9 provides a quick reference of WSR values for windowing the peripheral SFRs. Table
4-10 on page 4-14 lists the WSR values for windowing the upper register file.
Address:
Reset State:
0014H
00H
WSR
The window selection register (WSR) maps sections of RAM into the top of the lower register file, in
32-, 64-, or 128-byte increments. PUSHA saves this register on the stack and POPA restores it.
7
0
—
W6
W5
W4
W3
W2
W1
W0
Bit
Bit
Function
Number Mnemonic
7
—
Reserved; for compatibility with future devices, write zero to this bit.
Window Selection
6:0
W6:0
These bits specify the window size and number. See Table 4-9 on page
4-13 or Table 4-10 on page 4-14. See Table 4-9 for peripheral SFR windows
or Table 4-10 for upper register file windows.
Figure 4-3. Window Selection (WSR) Register
Table 4-9. Selecting a Window of Peripheral SFRs
WSR Value for
WSR Value for
WSR Value for
Peripherals
32-byte Window 64-byte Window 128-byte Window
(00E0–00FFH)
(00C0–00FFH)
(0080–00FFH)
Port 2
Waveform generator
7EH
3FH
Port 7 (MD only)
Peripheral interrupts
Pulse-width modulator
A/D converter
1FH
7DH
Frequency generator (MD only)
Reset control (MH only)
3EH
3DH
Port 1 (MH only)
Serial I/O port (MH only)
7CH
7BH
Timer 1–2
EPA compare 2–3 (MC)
EPA compare 0–5 (MD)
EPA compare 0–2 (MH)
1EH
EPA capture/compare 0–3 (MC)
EPA compare 0–1 (MC)
EPA capture/compare 0–5 (MD)
EPA capture/compare 0–1 (MH)
EPA compare 3 (MH)
7AH
4-13
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Table 4-10. Selecting a Window of the Upper Register File
WSR Value
for 32-byte Window
(00E0–00FFH)
WSR Value
for 64-byte Window
(00C0–00FFH)
WSR Value
for 128-byte Window
(0080–00FFH)
Register RAM
Locations
8XC196MH Only
02E0–02FFH
02C0–02DFH
02A0–02BFH
0280–029FH
0260–027FH
0240–025FH
0220–023FH
0200–021FH
57H
56H
55H
54H
53H
52H
51H
50H
2BH
2AH
29H
28H
15H
14H
8XC196MC, 8XC196MD, and 8XC196MH
01E0–01FFH
01C0–01DFH
01A0–01BFH
0180–019FH
0160–017FH
0140–015FH
0120–013FH
0100–011FH
4FH
4EH
4DH
4CH
4BH
4AH
49H
48H
27H
26H
25H
24H
13H
12H
4.2.2 Addressing a Location Through a Window
After you have selected the desired window, you need to know the windowed direct address of
the memory location (the address in the lower register file). Calculate the windowed direct ad-
dress as follows:
1. Subtract the base address of the area to be remapped (from Table 4-11 on page 4-15) from
the address of the desired location. This gives you the offset of that particular location.
2. Add the offset to the base address of the window (from Table 4-12 on page 4-15). The
result is the windowed direct address.
Appendix C includes a table of the windowable SFRs with the WSR values and windowed direct
addresses for each window size. Examples beginning on page 4-16 explain how to determine the
WSR value and windowed direct address for any windowable location. An additional example
shows how to set up a window by using the linker locator.
4-14
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MEMORY PARTITIONS
Table 4-11. Windows
WSR Value for
128-byte
Window
(0080–00FFH)
WSR Value
for 32-byte Window
WSR Value
for 64-byte Window
(00C0–00FFH)
Base
Address
(00E0–00FFH)
Peripheral SFRs
1FE0H
1FC0H
1FA0H
1F80H
1F60H
1F40H
1F20H
1F00H
02E0H
02C0H
02A0H
0280H
0260H
0240H
0220H
0200H
01E0H
01C0H
01A0H
0180H
0160H
0140H
0120H
0100H
7FH (Note)
7EH
7DH
7CH
7BH
7AH
79H
3FH (Note)
3EH
1FH (Note)
1EH
3DH
3CH
2BH
78H
57H
56H
55H
54H
2AH
15H
53H
52H
29H
51H
50H
28H
14H
4FH
4EH
4DH
4CH
4BH
4AH
49H
27H
26H
13H
25H
48H
24H
12H
NOTE: Locations 1FE0–1FFFH contain memory-mapped SFRs that cannot be accessed through a
window. Reading these locations through a window returns FFH; writing these locations
through a window has no effect.
Table 4-12. Windowed Base Addresses
WSR Windowed Base Address
Window Size
(Base Address in Lower Register File)
32-byte
64-byte
128-byte
00E0H
00C0H
0080H
4-15
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Appendix C includes a table of the windowable SFRs with the WSR values and direct addresses
for each window size. The following examples explain how to determine the WSR value and di-
rect address for any windowable location. An additional example shows how to set up a window
by using the linker locator.
4.2.2.1
32-byte Windowing Example
Assume that you wish to access location 014BH (a location in the upper register file used for gen-
eral-purpose register RAM) with register-direct addressing through a 32-byte window. Table 4-11
on page 4-15 shows that you need to write 4AH to the window selection register. It also shows
that the base address of the 32-byte memory area is 0140H. To determine the offset, subtract that
base address from the address to be accessed (014BH – 0140H = 000BH). Add the offset to the
base address of the window in the lower register file (00E0H, from Table 4-12). The direct ad-
dress is 00EBH (000BH + 00E0H).
4.2.2.2
64-byte Windowing Example
Assume that you wish to access the WG_CONTROL register (location 1FCCH) with register-di-
rect addressing through a 64-byte window. Table 4-11 shows that you need to write 3FH to the
window selection register. It also shows that the base address of the 64-byte memory area is
1FC0H. To determine the offset, subtract that base address from the address to be accessed
(1FCCH – 1FC0H = 000CH). Add the offset to the base address of the window in the lower reg-
ister file (00C0H, from Table 4-12). The direct address is 00CCH (000CH + 00C0H).
4.2.2.3
128-byte Windowing Example
Assume that you wish to access location 1F42H (the EPA0_TIME register) with register-direct
addressing through a 128-byte window. Table 4-11 shows that you need to write 1EH to the win-
dow selection register. It also shows that the base address of the 128-byte memory area is 1F00H.
To determine the offset, subtract that base address from the address to be accessed (1F42H –
1F00H = 0042H). Add the offset to the base address of the window in the lower register file
(0080H, from Table 4-12). The direct address is 00C2H (0042H + 0080H).
4.2.2.4
Unsupported Locations Windowing Example
Assume that you wish to access location 1FF1H (the P5_MODE register, a memory-mapped
SFR) with register-direct addressing through a 128-byte window. This location is in the range of
addresses (1FE0–1FFFH) that cannot be windowed. Although you could set up the window by
writing 1FH to the WSR, reading this location through the window would return FFH (all ones)
and writing to it would not change the contents. However, you could access the peripheral SFRs
in the range of 1F80–1FDFH with their windowed direct addresses.
4-16
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4.2.2.5
Using the Linker Locator to Set Up a Window
In this example, the linker locator is used to set up a window. The linker locator locates the win-
dow in the upper register file and determines the value to load in the WSR for access to that win-
dow. (Please consult the manual provided with the linker locator for details.)
********* mod1 **************
mod1 module main
public function1
extrn ?WSR
;Main module for linker
;Must declare ?WSR as external
wsr equ
14h:byte
sp
equ
18h:word
oseg
var1:
var2:
var3:
dsw 1
dsw 1
dsw 1
;Allocate variables in an
;overlayable segment
cseg
function1:
ldb
push wsr
;Prolog code for wsr
;Prolog code for wsr
wsr, #?WSR
add var1, var2, var3
;Use the variables as registers
;
;
;
ldb wsr, [sp]
add sp, #2
ret
;Epilog code for wsr
;Epilog code for wsr
end
******** mod2 **************
public function2
extrn ?WSR
wsr equ
14h:byte
18h:word
sp
equ
oseg
var1:
var2:
var3:
dsw 1
dsw 1
dsw 1
cseg
function2:
push wsr
;Prolog code for wsr
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ldb
wsr, #?WSR
;Prolog code for wsr
add var1, var2, var3
;
;
;
ldb wsr, [sp]
add sp, #2
ret
;Epilog code for wsr
;Epilog code for wsr
end
******************************
The following is an example of a linker invocation to link and locate the modules and to deter-
mine the proper windowing.
RL196 MOD1.OBJ, MOD2.OBJ registers(100h-01ffh) windowsize(32)
The above linker controls tell the linker to use registers 0100–01FFH for windowing and to use
a window size of 32 bytes. (These two controls enable windowing.)
The following is the map listing for the resultant output module (MOD1 by default):
SEGMENT MAP FOR mod1(MOD1):
TYPE
----
BASE
----
LENGTH
------
001AH
0006H
00E0H
0006H
0006H
1F74H
0011H
0011H
DF5EH
ALIGNMENT
---------
MODULE NAME
-----------
**RESERVED*
*** GAP ***
0000H
001AH
0020H
0100H
0106H
010CH
2080H
2091H
20A2H
STACK
WORD
OVRLY
OVRLY
WORD
WORD
MOD2
MOD1
*** GAP ***
*** GAP ***
CODE
CODE
BYTE
BYTE
MOD2
MOD1
This listing shows the disassembled code:
2080H
2082H
2085H
2089H
208CH
2090H
2091H
2093H
2096H
209AH
209DH
20A1H
;C814
| PUSH WSR
;B14814
;44E4E2E0
;B21814
;65020018
;F0
| LDB
| ADD
| LDB
| ADD
| RET
WSR,#48H
E0H,E2H,E4H
WSR,[SP]
SP,#02H
;C814
| PUSH WSR
;B14814
;44EAE8E6
;B21814
;65020018
;F0
| LDB
| ADD
| LDB
| ADD
| RET
WSR,#48H
E6H,E8H,EAH
WSR,[SP]
SP,#02H
4-18
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MEMORY PARTITIONS
The C compiler can also take advantage of this feature if the “windows” switch is enabled. For
details, see the MCS 96 microcontroller architecture software products in the Development Tools
Handbook.
4.2.3 Windowing and Addressing Modes
Once windowing is enabled, the windowed locations can be accessed both through the window
using direct (8-bit) addressing and by the usual 16-bit addressing. The lower register file locations
that are covered by the window are always accessible by indirect or indexed operations. To re-
enable direct access to the entire lower register file, clear the WSR. To enable direct access to a
particular location in the lower register file, you can select a smaller window that does not cover
that location.
When windowing is enabled:
• a register-direct instruction that uses an address within the lower register file actually
accesses the window in the upper register file;
• an indirect, indexed, or zero-register instruction that uses an address within either the lower
register file or the upper register file accesses the actual location in memory.
The following sample code illustrates the difference between register-direct and indexed address-
ing when using windowing.
PUSHA
LDB WSR, #12H
; pushes the contents of WSR onto the stack
; select window 12H, a 128-byte block
; The next instruction uses register-direct addr
; mem_word(40H)←mem_word(40H) + mem_word(380H)
; The next two instructions use indirect addr
; mem_word(40H)←mem_word(40H) + mem_word(80H +0)
; mem_word(40H)←mem_word(40H) + mem_word(380H +0)
; reloads the previous contents into WSR
ADD 40H, 80H
ADD 40H, 80H[0]
ADD 40H, 380H[0]
POPA
4-19
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5
Standard and PTS
Interrupts
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CHAPTER 5
STANDARD AND PTS INTERRUPTS
This chapter describes the interrupt control circuitry, priority scheme, and timing for standard and
peripheral transaction server (PTS) interrupts. It discusses the three special interrupts and the sev-
en PTS modes, four of which are used with the EPA to provide a software serial I/O channel for
both synchronous and asynchronous transfers and receptions. It also explains interrupt program-
ming and control.
5.1 OVERVIEW OF INTERRUPTS
The interrupt control circuitry within a microcontroller permits real-time events to control pro-
gram flow. When an event generates an interrupt, the device suspends the execution of current
instructions while it performs some service in response to the interrupt. When the interrupt is ser-
viced, program execution resumes at the point where the interrupt occurred. An internal periph-
eral, an external signal, or an instruction can generate an interrupt request. In the simplest case,
the device receives the request, performs the service, and returns to the task that was interrupted.
This microcontroller’s flexible interrupt-handling system has two main components: the pro-
grammable interrupt controller and the peripheral transaction server (PTS). The programmable
interrupt controller has a hardware priority scheme that can be modified by your software. Inter-
rupts that go through the interrupt controller are serviced by interrupt service routines that you
provide. The upper and lower interrupt vectors in special-purpose memory (see Chapter 4,
“Memory Partitions”) contain the interrupt service routines’ addresses. The peripheral transac-
tion server (PTS), a microcoded hardware interrupt processor, provides high-speed, low-over-
head interrupt handling; it does not modify the stack or the PSW. You can configure most
interrupts (except NMI, trap, and unimplemented opcode) to be serviced by the PTS instead of
the interrupt controller.
The PTS supports seven special microcoded routines that enable it to complete specific tasks in
much less time than an equivalent interrupt service routine can. It can transfer bytes or words,
either individually or in blocks, between any memory locations; manage multiple analog-to-dig-
ital (A/D) conversions; and transmit and receive serial data in either asynchronous or synchro-
nous mode (MC, MD only). PTS interrupts have a higher priority than standard interrupts and
may temporarily suspend interrupt service routines.
A block of data called the PTS control block (PTSCB) contains the specific details for each PTS
routine (see “Initializing the PTS Control Blocks” on page 5-24). When a PTS interrupt occurs,
the priority encoder selects the appropriate vector and fetches the PTS control block (PTSCB).
5-1
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Interrupt Pending or PTSSRV Bit Set
NMI
Pending
?
Yes
No
No
INT_MASK.x
= 1?
Return
Yes
PTS
Enabled?
No
No
No
Interrupts
Enabled
?
Return
Yes
Yes
PTSSEL.x
Bit = 1?
Priority
Encoder
Yes
Highest Priority Interrupt
Priority
Encoder
Yes
No
Highest Priority PTS Interrupt
PTSSRV.x
= 1?
Reset INT_PEND.x
Bit
Reset PTSSRV.x
Bit
Reset INT_PEND.x
Bit
Execute 1 PTS Cycle
(Microcoded)
Decrement
PTSCOUNT
PUSH PC
on Stack
LJMP to
ISR
No
Return
PTSCOUNT
= 0?
Execute Interrupt
Service Routine
Yes
Clear PTSSEL.x Bit
POP PC
from Stack
Set PTSSRV.x Bit
Return
Return
A0320-02
Figure 5-1. Flow Diagram for PTS and Standard Interrupts
5-2
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STANDARD AND PTS INTERRUPTS
Figure 5-1 illustrates the interrupt processing flow. In this flow diagram, “INT_MASK” repre-
sents both the INT_MASK and INT_MASK1 registers, and “INT_PEND” represents both the
INT_PEND and INT_PEND1 registers.
5.2 INTERRUPT SIGNALS AND REGISTERS
Table 5-1 describes the external interrupt signals and Table 5-2 describes the control and status
registers for both the interrupt controller and PTS.
Table 5-1. Interrupt Signals
Port Pin
Interrupt Signal Type
EXTINT I
Description
—
External Interrupt
This programmable interrupt is controlled by the
WG_PROTECT register. This register controls whether the
interrupt is edge triggered or sampled and whether a rising
edge/high level or falling edge/low level activates the
interrupt.
In powerdown mode, asserting the EXTINT signal for at least
50 ns causes the device to resume normal operation. The
interrupt need not be enabled. If the EXTINT interrupt is
enabled, the CPU executes the interrupt service routine.
Otherwise, the CPU executes the instruction that immediately
follows the command that invoked the power-saving mode.
In idle mode, asserting any enabled interrupt causes the
device to resume normal operation.
—
NMI
I
Nonmaskable Interrupt
In normal operating mode, a rising edge on NMI generates a
nonmaskable interrupt. NMI has the highest priority of all
prioritized interrupts. Assert NMI for greater than one state
time to guarantee that it is recognized.
Table 5-2. Interrupt and PTS Control and Status Registers
Address Description
0008H
Mnemonic
INT_MASK
Interrupt Mask Registers
INT_MASK1
0013H
These registers enable/disable each maskable interrupt (that is,
each interrupt except unimplemented opcode, software trap, and
NMI).
INT_PEND
0009H
0012H
Interrupt Pending Registers
INT_PEND1
The bits in this register are set by hardware to indicate that an
interrupt is pending.
PI_MASK
1FBCH
Peripheral Interrupt Mask
The bits in this register enable and disable (mask) the timer 1 and 2
overflow/underflow interrupt requests, the waveform generator
interrupt request (MC, MD), the EPA compare-only channel 5
interrupt request (MD), and the serial port error interrupts (MH).
5-3
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Table 5-2. Interrupt and PTS Control and Status Registers (Continued)
Mnemonic Address Description
PI_PEND 1FBEH Peripheral Interrupt Pending
Any bit set indicates a pending interrupt request.
No direct access Processor Status Word
This register contains one bit that globally enables or disables
PSW
servicing of all maskable interrupts and another that enables or
disables the PTS. These bits are set or cleared by executing the
enable interrupts (EI), disable interrupts (DI), enable PTS (EPTS),
and disable PTS (DPTS) instructions.
PTSSEL
PTSSRV
0004H, 0005H
0006H, 0007H
PTS Select Register
This register selects either a PTS routine or a standard interrupt
service routine for each of the maskable interrupt requests.
PTS Service Register
The bits in this register are set by hardware to request an end-of-
PTS interrupt.
5.3 INTERRUPT SOURCES AND PRIORITIES
Table 5-3 lists the interrupts sources, their default priorities (30 is highest and 0 is lowest), and
their vector addresses. The unimplemented opcode and software trap interrupts are not priori-
tized; they go directly to the interrupt controller for servicing. The priority encoder determines
the priority of all other pending interrupt requests. NMI has the highest priority of all prioritized
interrupts, PTS interrupts have the next highest priority, and standard interrupts have the lowest.
The priority encoder selects the highest priority pending request and the interrupt controller se-
lects the corresponding vector location in special-purpose memory. This vector contains the start-
ing (base) address of the corresponding PTS control block (PTSCB) or interrupt service routine.
PTSCBs must be located on a quad-word boundary in the internal register file.
5-4
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STANDARD AND PTS INTERRUPTS
Table 5-3. Interrupt Sources, Vectors, and Priorities
Interrupt Controller
Service
PTS Service
Interrupt Source
Mnemonic
Nonmaskable Interrupt
EXTINT Pin
NMI
INT15
203EH
203CH
30
14
—
—
—
EXTINT
INT14
PTS14
205CH
29
WF Gen (MC)
PI
WF Gen & EPA Comp 5 (MD) PI †
INT13
203AH
2038H
2036H
2034H
13
12
11
10
PTS13
205AH
28
27
26
25
WG
Waveform Generator (MH)
Reserved (MC)
—
EPA Cap/Comp 5 (MD)
SIO0 & 1 Receive Err (MH)
Reserved (MC)
EPA5
SPI †
INT12
INT11
INT10
PTS12
PTS11
PTS10
2058H
2056H
2054H
—
EPA Compare 4 (MD)
SIO1 Receive (MH)
Reserved (MC)
COMP4
RI1
—
EPA Cap/Comp 4 (MD)
SIO0 Receive (MH)
EPA Compare 3 (MC, MD)
EPA4
RI0
COMP3
TI1
INT09
INT08
2032H
2030H
09
08
PTS09
PTS08
2052H
2050H
24
23
SIO1 Transmit (MH)
EPA Cap/Comp 3 (MC, MD)
SIO0 Transmit (MH)
EPA3
TI0
Unimplemented Opcode
Software TRAP Instruction
EPA Compare 2 (MC, MD)
EPA Compare 3 (MH)
EPA Cap/Comp 2 (MC, MD)
EPA Compare 2 (MH)
EPA Compare 1
—
—
—
2012H
2010H
—
—
—
—
—
—
—
—
—
COMP2
COMP3
EPA2
INT07
INT06
200EH
200CH
07
06
PTS07
PTS06
204EH
204CH
22
21
COMP2
COMP1
EPA1
INT05
INT04
INT03
INT02
INT01
INT00
200AH
2008H
2006H
2004H
2002H
2000H
05
04
03
02
01
00
PTS05
PTS04
PTS03
PTS02
PTS01
PTS00
204AH
2048H
2046H
2044H
2042H
2040H
20
19
18
17
16
15
EPA Capture/Compare 1
EPA Compare 0
COMP0
EPA0
EPA Capture/Compare 0
A/D Conversion Complete
AD_DONE
OVRTM †
Timer 1 or 2 Overflow
†
PTS service is not useful for multiplexed interrupts because the PTS cannot readily determine the
source of these interrupts.
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5.3.1 Special Interrupts
This microcontroller has three special interrupt sources that are always enabled: unimplemented
opcode, software trap, and NMI. These interrupts are not affected by the EI (enable interrupts)
and DI (disable interrupts) instructions, and they cannot be masked. All of these interrupts are
serviced by the interrupt controller; they cannot be assigned to the PTS. Of these three, only NMI
goes through the transition detector and priority encoder. The other two special interrupts go di-
rectly to the interrupt controller for servicing. Be aware that these interrupts are often assigned to
special functions in development tools.
5.3.1.1
Unimplemented Opcode
If the CPU attempts to execute an unimplemented opcode, an indirect vector through location
2012H occurs. This prevents random software execution during hardware and software failures.
The interrupt vector should contain the starting address of an error routine that will not further
corrupt an already erroneous situation. The unimplemented opcode interrupt prevents other inter-
rupt requests from being acknowledged until after the next instruction is executed.
5.3.1.2
Software Trap
The TRAP instruction (opcode F7H) causes an interrupt call that is vectored through location
2010H. The TRAP instruction provides a single-instruction interrupt that is useful when debug-
ging software or generating software interrupts. The TRAP instruction prevents other interrupt
requests from being acknowledged until after the next instruction is executed.
5.3.1.3
NMI
The external NMI pin generates a nonmaskable interrupt for implementation of critical interrupt
routines. NMI has the highest priority of all the prioritized interrupts. It is passed directly from
the transition detector to the priority encoder, and it vectors indirectly through location 203EH.
The NMI pin is sampled during phase 2 (CLKOUT high) and is latched internally. Because inter-
rupts are edge-triggered, only one interrupt is generated, even if the pin is held high.
If your system does not use the NMI interrupt, connect the NMI pin to VSS to prevent spurious
interrupts.
5.3.2 External Interrupt Pin
The protection circuitry in the waveform generator (Figure 5-2) monitors the external interrupt
(EXTINT) signal. When it detects a valid event on the input, it sumultaneously disables the wave-
form generator outputs and generates an EXTINT interrupt request. Bits 2 and 3 in the waveform
generator protection (WG_PROTECT) register (Figure 9-9 on page 9-15) select the type of ex-
ternal event that will generate an interrupt request: a falling or rising edge or a low or high level.
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STANDARD AND PTS INTERRUPTS
When the level-sensitive event is selected, the external interrupt signal must remain asserted for
at least 24 TXTAL1 (24/FXTAL1) to be recognized as a valid interrupt. When the signal is asserted,
the level sampler samples the level of the signal three times during a 24 TXTAL1 period. When a
valid level occurs, the level sampler generates a a single output pulse. The output pulse generates
the EXTINT interrupt request. The level-sensitive mode is useful in noisy environments, where
a noise spike might cause an unintentional interrupt request.
When an edge-triggered event is selected, the input must remain asserted for at least two TXTAL1
(2/FXTAL1) to be recognized as a valid interrupt. When a valid transition occurs, the transition de-
tector generates a single output pulse. The output pulse generates the EXTINT interrupt request.
ES, IT
EXTINT
Interrupt
Request
DP
EO Bit
Register
Falling
Rising
00
01
Pulse
Transition
Detector
R
Q
S
OD#
EXTINT
FXTAL1
Low
10
11
Level
Sampler
High
CPU Write EO
CPU Read EO
CPU Bus
A2661-01
Figure 5-2. Waveform Generator Protection Circuitry
5.3.3 Multiplexed Interrupt Sources
The PI (MD), OVRTM (Mx), and SPI (MH) interrupts have multiple sources (see Table 5-3 on
page 5-5). An individual source will generate the interrupt only if software enables both the in-
terrupt source and multiplexed interrupt. To enable the multiplexed interrupt, set the appropriate
bit in the interrupt mask register (Figures 5-7 and 5-8). To enable an interrupt source, set the ap-
propriate bit in the PI_MASK register (Figure 5-9 on page 5-17). Figure 5-3 shows the flow for
the timer interrupt.
NOTE
Although the PI interrupt on the 8XC196MC has a single source (the
waveform generator), software must still enable both the source interrupt
(WG) in the PI_PEND register and the PI interrupt in the INT_MASK register.
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The interrupt service routine should read the PI_PEND (Figure 5-12 on page 5-23) register to de-
termine the source of the interrupt. Before executing the return instruction, the interrupt service
routine should check to see if any of the other interrupt sources are pending. Generally, PTS in-
terrupt service is not useful for multiplexed interrupts because the PTS cannot readily determine
the interrupt source.
Timer x
Overflows
Set OVRTMx
bit in PI_PEND
Is OVRTMx
bit set in
PI_MASK
?
OVRTM bit
is not set
in INT_PEND
No
Yes
Set OVRTM
bit in INT_PEND
Is OVRTM
bit set in
INT_MASK
?
No
OVRTM interrupt
is not generated
Yes
Generate
OVRTM interrupt
Read PI_PEND
to see which
timer overflowed
A3254-01
Figure 5-3. Flow Diagram for the OVRTM Interrupt
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STANDARD AND PTS INTERRUPTS
5.3.4 End-of-PTS Interrupts
When the PTSCOUNT register decrements to zero at the end of a single transfer, block transfer,
A/D scan, or serial I/O routine, hardware clears the corresponding bit in the PTSSEL register,
(Figure 5-6 on page 5-14) which disables PTS service for that interrupt. It also sets the corre-
sponding PTSSRV bit, requesting an end-of-PTS interrupt. An end-of-PTS interrupt has the same
priority as a corresponding standard interrupt. The interrupt controller processes it with an inter-
rupt service routine that is stored in the memory location pointed to by the standard interrupt vec-
tor. For example, the PTS services the EPA0 interrupt if PTSSEL.2 is set. The interrupt vectors
through 2044H, but the corresponding end-of-PTS interrupt vectors through 2004H, the standard
EPA0 interrupt vector. When the end-of-PTS interrupt vectors to the interrupt service routine,
hardware clears the PTSSRV bit. The end-of-PTS interrupt service routine should reinitialize the
PTSCB, if required, and set the appropriate PTSSEL bit to re-enable PTS interrupt service.
5.4 INTERRUPT LATENCY
Interrupt latency is the total delay between the time that the interrupt request is generated (not
acknowledged) and the time that the device begins executing either the standard interrupt service
routine or the PTS interrupt service routine. A delay occurs between the time that the interrupt
request is detected and the time that it is acknowledged. An interrupt request is acknowledged
when the current instruction finishes executing. If the interrupt request occurs during one of the
last four state times of the instruction, it may not be acknowledged until after the next instruction
finishes. This additional delay occurs because instructions are prefetched and prepared a few state
times before they are executed. Thus, the maximum delay between interrupt request and ac-
knowledgment is four state times plus the execution time of the next instruction.
When a standard interrupt request is acknowledged, the hardware clears the interrupt pending bit
and forces a call to the address contained in the corresponding interrupt vector. When a PTS in-
terrupt request is acknowledged, the hardware immediately vectors to the PTSCB and begins ex-
ecuting the PTS routine.
5.4.1 Situations that Increase Interrupt Latency
If an interrupt request occurs while any of the following instructions are executing, the interrupt
will not be acknowledged until after the next instruction is executed:
• the signed prefix opcode (FE) for the two-byte, signed multiply and divide instructions
• any of these eight protected instructions: DI, EI, DPTS, EPTS, POPA, POPF, PUSHA,
PUSHF (see Appendix A for descriptions of these instructions)
• any of the read-modify-write instructions: AND, ANDB, OR, ORB, XOR, XORB
Both the unimplemented opcode interrupt and the software trap interrupt prevent other interrupt
requests from being acknowledged until after the next instruction is executed.
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Each PTS cycle within a PTS routine cannot be interrupted. A PTS cycle is the entire PTS re-
sponse to a single interrupt request. In block transfer mode, a PTS cycle consists of the transfer
of an entire block of bytes or words. This means a worst-case latency of 500 states if you assume
a block transfer of 32 words from one external memory location to another. See Table 5-4 on page
5-12 for PTS cycle execution times.
5.4.2 Calculating Latency
The maximum latency occurs when the interrupt request occurs too late for acknowledgment fol-
lowing the current instruction. The following worst-case calculation assumes that the current in-
struction is not a protected instruction. To calculate latency, add the following terms:
• Time for the current instruction to finish execution (4 state times).
— If this is a protected instruction, the instruction that follows it must also execute before
the interrupt can be acknowledged. Add the execution time of the instruction that
follows a protected instruction.
• Time for the next instruction to execute. (The longest instruction, NORML, takes 39 state
times. However, the BMOV instruction could actually take longer if it is transferring a large
block of data. If your code contains routines that transfer large blocks of data, you may get a
more accurate worst-case value if you use the BMOV instruction in your calculation instead
of NORML. See Appendix A for instruction execution times.)
• For standard interrupts only, the response time to get the vector and force the call.
— 11 state times for an internal stack or 13 for an external stack (assuming a zero-wait-
state bus)
5.4.2.1
Standard Interrupt Latency
The worst-case delay for a standard interrupt is 56 state times (4 + 39 + 11 + 2) if the stack is in
external memory (Figure 5-4). This delay time does not include the time needed to execute the
first instruction in the interrupt service routine or to execute the instruction following a protected
instruction.
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STANDARD AND PTS INTERRUPTS
39
11
2
12
6
4
3
2
1
If Stack
External
Ending
Instruction
End
"NORML"
Call is
Forced
If Stack
External
"NORML"
Execution
EXTINT
"PUSHA"
Interrupt Routine
Pending
Interrupt
Set
Cleared
56 State Times
Response
Time
A0136-02
Figure 5-4. Standard Interrupt Response Time
PTS Interrupt Latency
5.4.2.2
The maximum delay for a PTS interrupt is 43 state times (4 + 39) as shown in Figure 5-5. This
delay time does not include the added delay if a protected instruction is being executed or if a PTS
request is already in progress. See Table 5-4 for execution times for PTS cycles.
4
3
2
1
39
Ending
Instruction
End
"NORML"
Vector to PTS
Control Block
"NORML"
PTS
Execution
EXTINT
PTS
PTS Interrupt Routine
Pending
Interrupt
Set
Cleared
Latency Time
43 State Times
Response Time
A0142-01
Figure 5-5. PTS Interrupt Response Time
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Table 5-4. Execution Times for PTS Cycles
PTS Mode Execution Time (in State Times)
Single transfer mode
register/register†
memory/register†
memory/memory†
18 per byte or word transfer + 1
21 per byte or word transfer + 1
24 per byte or word transfer + 1
Block transfer mode
register/register†
memory/register†
memory/memory†
13 + 7 per byte or word transfer (1 minimum)
16 + 7 per byte or word transfer (1 minimum)
19 + 7 per byte or word transfer (1 minimum)
A/D scan mode
register/register†
register/memory†
21
25
ASIO receive mode (MC, MD only)
Majority disabled
24 + 2 (if parity enabled)
Majority enabled
36 + sample time (second sample)
36 + 7 + sample time (third sample)
36 + 2 (if parity enabled)
ASIO transmit mode (MC, MD only)
SSIO receive mode (MC, MD only)
29 + 3 (if parity enabled)
29 (receive data bit)
21 (no reception)
SSIO transmit mode (MC, MD only)
30 (transmit data bit)
20 (no transmission)
†
Register indicates an access to the register file or peripheral SFR. Memory indicates an access to a
memory-mapped register, I/O, or memory. See Table 4-1 on page 4-2 for address information.
5.5 PROGRAMMING THE INTERRUPTS
The PTS select register (PTSSEL) selects either PTS service or a standard software interrupt ser-
vice routine for each of the maskable interrupt requests (see Figure 5-6). The bits in the interrupt
mask registers, INT_MASK and INT_MASK1, enable or disable (mask) individual interrupts
(see Figures 5-7 and 5-8). For the multiplexed interrupt sources, bits in the PI_MASK register
(Figure 5-9 on page 5-17) enable or disable (mask) the individual interrupt sources. With the ex-
ception of the nonmaskable interrupt (NMI) bit (INT_MASK1.7), setting a bit enables the corre-
sponding interrupt source and clearing a bit disables the source.
To disable any interrupt, clear its mask bit. To enable an interrupt for standard interrupt service,
set its mask bit and clear its PTS select bit. To enable an interrupt for PTS service, set both the
mask bit and the PTS select bit.
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STANDARD AND PTS INTERRUPTS
When you assign an interrupt to the PTS, you must set up a PTS control block (PTSCB) for each
interrupt source (see “Initializing the PTS Control Blocks” on page 5-24) and use the EPTS in-
struction to globally enable the PTS. When you assign an interrupt to a standard software service
routine, use the EI (enable interrupts) instruction to globally enable interrupt servicing.
NOTE
The DI (disable interrupts) instruction does not disable PTS service. However,
it does disable service for the end-of-PTS interrupt request. If an interrupt
request occurs while interrupts are disabled, the corresponding pending bit is
set in the INT_PEND or INT_PEND1 register.
PTS service is not useful for multiplexed interrupts because the PTS cannot
readily determine the source of these interrupts.
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PTSSEL
Address:
Reset State:
0004H
0000H
The PTS select (PTSSEL) register selects either a PTS microcode routine or a standard interrupt
service routine for each interrupt request. Setting a bit selects a PTS microcode routine; clearing a bit
selects a standard interrupt service routine. When PTSCOUNT reaches zero, hardware clears the
corresponding PTSSEL bit. The PTSSEL bit must be set manually to re-enable the PTS channel.
15
8
0
8XC196MC
8XC196MD
8XC196MH
—
EXTINT
EPA2
PI
—
—
—
COMP3
AD
EPA3
7
COMP2
COMP1
EPA1
COMP0
EPA0
OVRTM
15
8
—
7
EXTINT
EPA2
PI
EPA5
EPA1
COMP4
COMP0
EPA4
EPA0
COMP3
AD
EPA3
0
COMP2
COMP1
OVRTM
15
—
7
8
EXTINT
WG
SPI
RI1
RI0
TI1
AD
TI0
0
COMP3 COMP2 COMP1
EPA1
COMP0
EPA0
OVRTM
Bit
Number
Function
Reserved; for compatibility with future devices, write zero to this bit.
15
14:0†
Setting a bit causes the corresponding interrupt to be handled by a PTS microcode routine.
The PTS interrupt vector locations are as follows:
Bit Mnemonic
EXTINT
PTS Vector
205CH
205AH
205AH
2058H
2058H
2056H
2056H
2054H
2054H
Bit Mnemonic
TI0 (MH)
PTS Vector
2050H
204EH
204EH
204CH
204CH
204AH
2048H
2046H
2044H
2042H
2040H
PI (MC, MD)††
WG (MH)
COMP2 (MC,MD)
COMP3 (MH)
EPA2 (MC, MD)
COMP2 (MH)
COMP1
EPA1
COMP0
EPA0
AD
OVRTM††
EPA5 (MD)
SPI (MH)††
COMP4 (MD)
RI1 (MH)
EPA4 (MD)
RI0 (MH)
COMP3 (MC, MD) 2052H
TI1 (MH)
2052H
EPA3 (MC, MD)
2050H
††
PTS service is not useful for multiplexed interrupts because the PTS cannot readily
determine the source of these interrupts.
†
On the 8XC196MC device bits 10–12 are reserved. For compatibility with future devices, write zeros
to these bits.
Figure 5-6. PTS Select (PTSSEL) Register
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STANDARD AND PTS INTERRUPTS
Address:
Reset State:
0008H
00H
INT_MASK
The interrupt mask (INT_MASK) register enables or disables (masks) individual interrupt requests.
(The EI and DI instructions enable and disable servicing of all maskable interrupts.) INT_MASK is the
low byte of the processor status word (PSW). PUSHF or PUSHA saves the contents of this register
onto the stack and then clears this register. Interrupt calls cannot occur immediately following this
instruction. POPF or POPA restores it.
7
0
MC, MD
MH
COMP2
EPA2
COMP1
EPA1
EPA1
COMP0
COMP0
EPA0
EPA0
AD
AD
OVRTM
7
0
COMP3 COMP2 COMP1
OVRTM
Bit
Number
Function
7:0
Setting a bit enables the corresponding interrupt.
The standard interrupt vector locations are as follows:
Bit Mnemonic
COMP2 (MC, MD) EPA Compare-only Channel 2
Interrupt
Standard Vector
200EH
COMP3 (MH)
EPA2 (MC, MD)
COMP2 (MH)
COMP1
EPA Compare-only Channel 3
EPA Capture/Compare Channel 2
EPA Compare Channel 2
200EH
200CH
200EH
200AH
EPA Compare Channel 1
EPA1
COMP0
EPA Capture/Compare Channel 1
EPA Compare Channel 0
2008H
2006H
EPA0
AD
OVRTM†
EPA Capture/Compare Channel 0
A/D Conversion Complete
Overflow/Underflow Timer
2004H
2002H
2000H
†
Both timer 1 and timer 2 can generate the multiplexed overflow/underflow interrupt. Write
to PI_MASK to enable the interrupt sources; read PI_PEND to determine which source
caused the interrupt.
Figure 5-7. Interrupt Mask (INT_MASK) Register
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INT_MASK1
Address:
Reset State:
0013H
00H
The interrupt mask 1 (INT_MASK1) register enables or disables (masks) individual interrupt requests.
(The EI and DI instructions enable and disable servicing of all maskable interrupts.) INT_MASK1 can
be read from or written to as a byte register. PUSHA saves this register on the stack and POPA
restores it.
7
7
7
0
8XC196MC
8XC196MD
8XC196MH
NMI
NMI
NMI
EXTINT
EXTINT
EXTINT
PI
PI
—
—
COMP4
RI1
—
COMP3
COMP3
TI1
EPA3
EPA3
TI0
0
0
EPA5
SPI
EPA4
RI0
WG
Bit
Number
Function
7:0†
Setting a bit enables the corresponding interrupt.
The standard interrupt vector locations are as follows:
Bit Mnemonic
NMI
EXTINT
PI (MC, MD)††
WG (MH)
EPA5 (MD)
SPI (MH)†††
COMP4 (MD)
RI1 (MH)
Interrupt
Nonmaskable Interrupt
EXTINT pin
Multiplexed Peripheral Interrupt
Waveform Generator
EPA Capture/Compare Channel 5
Serial Port
EPA Compare Channel 4
SIO 1 Receive
Standard Vector
203EH
203CH
203AH
203AH
2038H
2038H
2036H
2036H
EPA4 (MD)
RI0 (MH)
EPA Capture/Compare Channel 4
SIO 0 Receive
2034H
2034H
COMP3 (MC, MD) EPA Compare Channel 3
2032H
TI1 (MH)
SIO 1 Transmit
2032H
EPA3 (MC, MD)
EPA Capture/Compare Channel 3
2030H
TI0 (MH)
SIO 0 Transmit
2030H
††
The waveform generator and the EPA compare-only channel 5 can generate this
interrupt. Write to PI_MASK to enable the interrupt sources; read PI_PEND to
determine which source caused the interrupt.
††† SIO 0 and SIO 1 can generate this interrupt. Write to PI_MASK to enable the interrupt
sources; read PI_PEND to determine which source caused the interrupt.
†
On the 8XC196MC device bits 4–3 are reserved. For compatibility with future devices, write zeros to
these bits.
Figure 5-8. Interrupt Mask 1 (INT_MASK1) Register
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STANDARD AND PTS INTERRUPTS
Address:
Reset State:
1FBCH
AAH
PI_MASK
The peripheral interrupt mask (PI_MASK) register enables or disables (masks) interrupt requests
associated with the peripheral interrupt (PI), the serial port interrupt (SPI), and the overflow/underflow
timer interrupt (OVRTM).
7
7
7
0
—
—
—
—
—
—
—
WG
WG
SP0
—
—
—
OVRTM2
OVRTM2
OVRTM2
—
—
—
OVRTM1
8XC196MC
8XC196MD
8XC196MH
0
COMP5
SP1
OVRTM1
0
OVRTM1
Bit
Number
Bit
Mnemonic
Function
7, 5, 3, 1
6
—
Reserved; for compatibility with future devices, write zeros to these bits.
Reserved; for compatibility with future devices, write zero to this bit.
— (MC)
COMP5 (MD) EPA Compare Channel 5
Setting this bit enables the EPA compare channel 5 interrupt.
The EPA compare channel 5 and the waveform generator interrupts are
associated with the peripheral interrupt (PI). Setting INT_MASK1.5
enables PI.
SP1 (MH)
Serial Port 1 Error
Setting this bit enables the serial port 1 error interrupt.
The serial port 1 and serial port 0 error interrupts are associated with the
serial port interrupt (SPI). Setting INT_MASK1.4 enables SPI.
4
WG (MC, MD) Waveform Generator
Setting this bit enables the waveform generator interrupt.
The waveform generator and the EPA compare channel 5 interrupts are
associated with the peripheral interrupt (PI). Setting INT_MASK1.5
enables PI.
SP0 (MH)
OVRTM2
Serial Port 0 Error
Setting this bit enables the serial port 0 error interrupt.
The serial port 0 and serial port 1 error interrupts are associated with the
serial port interrupt (SPI). Setting INT_MASK1.4 enables SPI.
2
Timer 2 Overflow/Underflow
Setting this bit enables the timer 2 overflow/underflow interrupt.
The timer 2 and timer 1 overflow/underflow interrupts are associated with
the overflow/underflow timer interrupt (OVRTM). Setting INT_MASK.0
enables OVRTM.
Figure 5-9. Peripheral Interrupt Mask (PI_MASK) Register
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PI_MASK (Continued)
Address:
Reset State:
1FBCH
AAH
The peripheral interrupt mask (PI_MASK) register enables or disables (masks) interrupt requests
associated with the peripheral interrupt (PI), the serial port interrupt (SPI), and the overflow/underflow
timer interrupt (OVRTM).
7
7
7
0
—
—
—
—
—
—
—
WG
WG
SP0
—
—
—
OVRTM2
OVRTM2
OVRTM2
—
—
—
OVRTM1
8XC196MC
8XC196MD
8XC196MH
0
COMP5
SP1
OVRTM1
0
OVRTM1
Bit
Number
Bit
Mnemonic
Function
0
OVRTM1
Timer 1 Overflow/Underflow
Setting this bit enables the timer 1 overflow/underflow interrupt.
The timer 1 and timer 2 overflow/underflow interrupts are associated with
the overflow/underflow timer interrupt (OVRTM). Setting INT_MASK.0
enables OVRTM.
Figure 5-9. Peripheral Interrupt Mask (PI_MASK) Register (Continued)
5.5.1 Modifying Interrupt Priorities
Your software can modify the default priorities of maskable interrupts by controlling the interrupt
mask registers (INT_MASK and INT_MASK1). For example, you can specify which interrupts,
if any, can interrupt an interrupt service routine. The following code shows one way to prevent
all interrupts, except EXTINT (priority 14), from interrupting an A/D conversion-complete inter-
rupt service routine (priority 01).
SERIAL_RI_ISR:
PUSHA
; Save PSW, INT_MASK, INT_MASK1, & WSR
; (this disables all interrupts)
; Enable EXTINT only
LDB INT_MASK1, #01000000B
EI
; Enable interrupt servicing
; Service the AD_DONE interrupt
POPA
RET
; Restore PSW, INT_MASK, INT_MASK1, &
; WSR registers
CSEG AT 02002H
DCW AD_DONE_ISR
; fill in interrupt table
END
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STANDARD AND PTS INTERRUPTS
Note that location 2002H in the interrupt vector table must be loaded with the value of the label
AD_DONE_ISR before the interrupt request occurs and that the A/D conversion complete inter-
rupt must be enabled for this routine to execute.
This routine, like all interrupt service routines, is handled in the following manner:
1. After the hardware detects and prioritizes an interrupt request, it generates and executes an
interrupt call. This pushes the program counter onto the stack and then loads it with the
contents of the vector corresponding to the highest priority, pending, unmasked interrupt.
The hardware will not allow another interrupt call until after the first instruction of the
interrupt service routine is executed.
2. The PUSHA instruction saves the contents of the PSW, INT_MASK, INT_MASK1, and
window selection register (WSR) onto the stack and then clears the PSW, INT_MASK,
and INT_MASK1 registers. In addition to the arithmetic flags, the PSW contains the
global interrupt enable bit (I) and the PTS enable bit (PSE). By clearing the PSW and the
interrupt mask registers, PUSHA effectively masks all maskable interrupts, disables
standard interrupt servicing, and disables the PTS. Because PUSHA is a protected
instruction, it also inhibits interrupt calls until after the next instruction executes.
3. The LDB INT_MASK1 instruction enables those interrupts that you choose to allow to
interrupt the service routine. In this example, only EXTINT can interrupt the receive
interrupt service routine. By enabling or disabling interrupts, the software establishes its
own interrupt servicing priorities.
4. The EI instruction re-enables interrupt processing and inhibits interrupt calls until after the
next instruction executes.
5. The actual interrupt service routine executes within the priority structure established by
the software.
6. At the end of the service routine, the POPA instruction restores the original contents of the
PSW, INT_MASK, INT_MASK1, and WSR registers; any changes made to these
registers during the interrupt service routine are overwritten. Because interrupt calls
cannot occur immediately following a POPA instruction, the last instruction (RET) will
execute before another interrupt call can occur.
Notice that the “preamble” and exit code for this routine do not save or restore register RAM. The
interrupt service routine is assumed to allocate its own private set of registers from the lower reg-
ister file. The general-purpose register RAM in the lower register file makes this quite practical.
In addition, the RAM in the upper register file is available via windowing (see “Windowing” on
page 4-12).
5-19
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5.5.2 Determining the Source of an Interrupt
When hardware detects an interrupt, it sets the corresponding bit in the INT_PEND or
INT_PEND1 register (Figures 5-10 and 5-11 ). It sets the bit even if the individual interrupt is
disabled (masked). Hardware clears the pending bit when the program vectors to the interrupt ser-
vice routine. The interrupt service routine can read INT_PEND and INT_PEND1 to determine
which interrupts are pending.
Software can generate an interrupt by setting a bit in INT_PEND or INT_PEND1 register. We
recommend the use of the read-modify-write instructions, such as AND and OR, to modify these
registers.
ANDB INT_PEND, #11111110B
ORB INT_PEND, #00000001B
; Clears the OVRTM pending bit
; Sets the OVRTM pending bit
Other methods could result in a partial interrupt cycle. For example, an interrupt could occur dur-
ing an instruction sequence that loads the contents of the interrupt pending register into a tempo-
rary register, modifies the contents of the temporary register, and then writes the contents of the
temporary register back into the interrupt pending register. If the interrupt occurs during one of
the last four states of the second instruction, it will not be acknowledged until after the completion
of the third instruction. Because the third instruction overwrites the contents of the interrupt pend-
ing register, the jump to the interrupt vector will not occur.
The PI (MD), SPI (MH), and OVRTM (Mx) interrupts have multiple sources. Read PI_PEND
(Figure 5-12 on page 5-23) to determine which source generated the interrupt request. Reading
PI_PEND clears all the bits. PI_PEND is a read-only register.
5-20
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STANDARD AND PTS INTERRUPTS
Address:
Reset State:
0009H
00H
INT_PEND
When hardware detects an interrupt request, it sets the corresponding bit in the interrupt pending
(INT_PEND or INT_PEND1) registers. When the vector is taken, the hardware clears the pending bit.
Software can generate an interrupt by setting the corresponding interrupt pending bit.
7
0
MC, MD
MH
COMP2
EPA2
COMP1
EPA1
EPA1
COMP0
COMP0
EPA0
EPA0
AD
AD
OVRTM
7
0
COMP3 COMP2 COMP1
OVRTM
Bit
Number
Function
7:0
Any set bit indicates that the corresponding interrupt is pending. The interrupt bit is cleared
when processing transfers to the corresponding interrupt vector.
The standard interrupt vector locations are as follows:
Bit Mnemonic
COMP2 (MC, MD) EPA Compare Channel 2
Interrupt
Standard Vector
200EH
COMP3 (MH)
EPA2 (MC, MD)
COMP2 (MH)
COMP1
EPA Compare Channel 3
EPA Capture/Compare Channel 2
EPA Compare Channel 2
200EH
200CH
200EH
EPA Compare Channel 1
200AH
EPA1
EPA Capture/Compare Channel 1
2008H
COMP0
EPA Compare Channel 0
2006H
EPA0
AD
OVRTM†
EPA Capture/Compare Channel 0
A/D Conversion Complete
Overflow/Underflow Timer
2004H
2002H
2000H
†
Timer 1 and timer 2 can generate the multiplexed overflow/underflow interrupt. Write to
PI_MASK to enable the interrupt sources; read PI_PEND to determine which source
caused the interrupt.
Figure 5-10. Interrupt Pending (INT_PEND) Register
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INT_PEND1
Address:
Reset State:
0012H
00H
When hardware detects a pending interrupt, it sets the corresponding bit in the interrupt pending
(INT_PEND or INT_PEND1) registers. When the vector is taken, the hardware clears the pending bit.
Software can generate an interrupt by setting the corresponding interrupt pending bit.
7
7
7
0
8XC196MC
8XC196MD
8XC196MH
NMI
NMI
NMI
EXTINT
EXTINT
EXTINT
PI
PI
—
—
COMP4
RI1
—
COMP3
COMP3
TI1
EPA3
EPA3
TI0
0
0
EPA5
SPI
EPA4
RI0
WG
Bit
Number
Function
7:0†
Setting a bit enables the corresponding interrupt.
The standard interrupt vector locations are as follows:
Bit Mnemonic
NMI
EXTINT
PI (MC, MD)††
WG (MH)
EPA5 (MD)
SPI (MH)†††
COMP4 (MD)
RI1 (MH)
Interrupt
Nonmaskable Interrupt
EXTINT pin
Multiplexed Peripheral Interrupt
Waveform Generator
EPA Capture/Compare Channel 5
Serial Port
EPA Compare Channel 4
SIO 1 Receive
Standard Vector
203EH
203CH
203AH
203AH
2038H
2038H
2036H
2036H
EPA4 (MD)
RI0 (MH)
EPA Capture/Compare Channel 4
SIO 0 Receive
2034H
2034H
COMP3 (MC, MD) EPA Compare Channel 3
2032H
TI1 (MH)
SIO 1 Transmit
2032H
EPA3 (MC, MD)
TI0 (MH)
EPA Capture/Compare Channel 3
SIO 0 Transmit
2030H
2030H
††
On the 8XC196MD, the waveform generator and the EPA compare channel 5 can
generate this interrupt. Write to PI_MASK to enable the interrupt sources; read
PI_PEND to determine which source caused the interrupt. On the 8XC196MC, the
waveform generator is the sole source for this interrupt.
††† SIO 0 and SIO 1 can generate this interrupt. Write to PI_MASK to enable the interrupt
sources; read PI_PEND to determine which source caused the interrupt.
†
On the 8XC196MC device bits 4–3 are reserved. These bits are undefined.
Figure 5-11. Interrupt Pending 1 (INT_PEND1) Register
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STANDARD AND PTS INTERRUPTS
Address:
Reset State:
1FBEH
AAH
PI_PEND
When hardware detects a pending peripheral or timer interrupt, it sets the corresponding bit in the
interrupt pending (INT_PEND or INT_PEND1) registers and the peripheral interrupt pending
(PI_PEND) register. When the vector is taken, the hardware clears the INT_PEND/INT_PEND1
pending bit. Reading this register clears all the PI_PEND bits. Software can generate an interrupt by
setting a PI_PEND bit.
7
0
—
—
—
—
—
—
—
WG
WG
SP0
—
—
—
OVRTM2
OVRTM2
OVRTM2
—
—
—
OVRTM1
8XC196MC
8XC196MD
8XC196MH
7
7
0
COMP5
SP1
OVRTM1
0
OVRTM1
Bit
Number
Bit
Mnemonic
Function
7, 5, 3, 1
6
—
Reserved. These bits are undefined.
Reserved. This bit is undefined.
— (MC)
COMP5 (MD) EPA Compare Channel 5
When set, this bit indicates a pending EPA compare channel 5 interrupt.
The EPA compare channel 5 and the waveform generator interrupts are
associated with the peripheral interrupt (PI). Setting INT_MASK1.5
enables PI. Setting PI_MASK.6 enables COMP5.
SP1 (MH)
Serial Port 1 Error
When set, this bit indicates a pending serial port 1 error interrupt.
The serial port 1 and 0 error interrupts are associated with the serial port
interrupt (SPI). Setting INT_MASK1.4 enables SPI. Setting PI_MASK.6
enables SP1.
4
WG (MC, MD) Waveform Generator
When set, this bit indicates a pending waveform generator interrupt.
The waveform generator and the EPA compare channel 5 interrupts are
associated with the peripheral interrupt (PI). Setting INT_MASK1.5
enables PI. Setting PI_MASK.5 enables WG.
SP0 (MH)
Serial Port 0 Error
When set, this bit indicates a pending serial port 0 error interrupt.
The serial port 0 and 1 error interrupts are associated with the serial port
interrupt (SPI). Setting INT_MASK1.4 enables SPI. Setting PI_MASK.4
enables SP0.
Figure 5-12. Peripheral Interrupt Pending (PI_PEND) Register
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PI_PEND (Continued)
Address:
Reset State:
1FBEH
AAH
When hardware detects a pending peripheral or timer interrupt, it sets the corresponding bit in the
interrupt pending (INT_PEND or INT_PEND1) registers and the peripheral interrupt pending
(PI_PEND) register. When the vector is taken, the hardware clears the INT_PEND/INT_PEND1
pending bit. Reading this register clears all the PI_PEND bits. Software can generate an interrupt by
setting a PI_PEND bit.
7
0
—
—
—
—
—
—
—
WG
WG
SP0
—
—
—
OVRTM2
OVRTM2
OVRTM2
—
—
—
OVRTM1
8XC196MC
8XC196MD
8XC196MH
7
7
0
COMP5
SP1
OVRTM1
0
OVRTM1
Bit
Number
Bit
Mnemonic
Function
2
0
OVRTM2
Timer 2 Overflow/Underflow
When set, this bit indicates a pending timer 2 overflow/underflow interrupt.
The timer 2 and timer 1 overflow/underflow interrupts are associated with
the overflow/underflow timer interrupt (OVRTM). Setting INT_MASK.0
enables OVRTM. Setting PI_MASK.2 enables OVRTM2.
OVRTM1
Timer 1 Overflow/Underflow
When set, this bit indicates a pending timer 1 overflow/underflow interrupt.
The timer 1 and timer 2 overflow/underflow interrupts are associated with
the overflow/underflow timer interrupt (OVRTM). Setting INT_MASK.0
enables OVRTM. Setting PI_MASK.0 enables OVRTM1.
Figure 5-12. Peripheral Interrupt Pending (PI_PEND) Register (Continued)
5.6 INITIALIZING THE PTS CONTROL BLOCKS
Each PTS interrupt requires a block of data, in register RAM, called the PTS control block
(PTSCB). The PTSCB identifies which PTS microcode routine will be invoked and sets up the
specific parameters for the routine. You must set up the PTSCB for each interrupt source before
enabling the corresponding PTS interrupts.
5-24
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STANDARD AND PTS INTERRUPTS
The address of the first (lowest) PTSCB byte is stored in the PTS vector table in special-purpose
memory (see “Special-purpose Memory” on page 4-3). Figure 5-13 shows the PTSCB for each
PTS mode. Unused PTSCB bytes can be used as extra RAM.
NOTE
The PTSCB must be located in the internal register file. The location of the
first byte of the PTSCB must be aligned on a quad-word boundary (an address
evenly divisible by 8).
Single
Transfer
Block
Transfer
A/D Scan
Mode
SIO #1†
SIO #2†
Unused
Unused
Unused
Unused
PTSVEC1 (H)
PTSVEC1 (L)
BAUD (H)
Unused
PTSBLOCK
PTSDST (H)
PTSDST (L)
PTSSRC (H)
PTSSRC (L)
PTSCON
Unused
SAMPTIME
DATA (H)
PTSDST(H)
PTSDST (L)
PTSSRC (H)
PTSSRC (L)
PTSCON
PTSPTR2 (H)
PTSPTR2 (L)
PTSPTR1 (H)
PTSPTR1 (L)
PTSCON
BAUD (L)
DATA (L)
EPAREG (H)
EPAREG (L)
PTSCON
PTSCON1
PORTMASK
PORTREG (H)
PORTREG (L)
PTSVECT
PTSCOUNT
PTSCOUNT
PTSCOUNT
PTSCOUNT
†
8XC196MC and MD only.
Figure 5-13. PTS Control Blocks
5.6.1 Specifying the PTS Count
The first location of the PTSCB contains an 8-bit value called PTSCOUNT. This value defines
the number of interrupts that will be serviced by the PTS routine. The PTS decrements
PTSCOUNT after each PTS cycle. When PTSCOUNT reaches zero, hardware clears the corre-
sponding PTSSEL bit and sets the PTSSRV bit (Figure 5-6), which requests an end-of-PTS inter-
rupt. The end-of-PTS interrupt service routine should reinitialize the PTSCB, if required, and set
the appropriate PTSSEL bit to re-enable PTS interrupt service.
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PTSSRV
Address:
Reset State:
0006H
0000H
The PTS service (PTSSRV) register is used by the hardware to indicate that the final PTS interrupt has
been serviced by the PTS routine. When PTSCOUNT reaches zero, hardware clears the corre-
sponding PTSSEL bit and sets the PTSSRV bit, which requests the end-of-PTS interrupt. When the
end-of-PTS interrupt is called, hardware clears the PTSSRV bit. The PTSSEL bit must be set manually
to re-enable the PTS channel.
15
8
8XC196MC
8XC196MD
8XC196MH
—
EXTINT
EPA2
PI
—
—
—
COMP3
AD
EPA3
7
0
COMP2
COMP1
EPA1
COMP0
EPA0
OVRTM
15
8
—
7
EXTINT
EPA2
PI
EPA5
EPA1
COMP4
COMP0
EPA4
EPA0
COMP3
AD
EPA3
0
COMP2
COMP1
OVRTM
15
—
7
8
EXTINT
WG
SPI
RI1
RI0
TI1
AD
TI0
0
COMP3 COMP2 COMP1
EPA1
COMP0
EPA0
OVRTM
Bit
Number
Function
15
Reserved. This bit is undefined.
14:0†
A bit is set by hardware to request an end-of-PTS interrupt for the corresponding interrupt
through its standard interrupt vector.
The PTS interrupt vector locations are as follows:
Bit Mnemonic
EXTINT
PTS Vector
205CH
205AH
205AH
2058H
2058H
2056H
2056H
2054H
2054H
Bit Mnemonic
TI0 (MH)
PTS Vector
2050H
204EH
204EH
204CH
204CH
204AH
2048H
2046H
2044H
2042H
2040H
PI (MC, MD)††
WG (MH)
COMP2 (MC,MD)
COMP3 (MH)
EPA2 (MC, MD)
COMP2 (MH)
COMP1
EPA1
COMP0
EPA0
AD
OVRTM††
EPA5 (MD)
SPI (MH)††
COMP4 (MD)
RI1 (MH)
EPA4 (MD)
RI0 (MH)
COMP3 (MC, MD) 2052H
TI1 (MH)
2052H
EPA3 (MC, MD)
2050H
††
PTS service is not useful for multiplexed interrupts because the PTS cannot readily
determine the source of these interrupts.
†
On the 8XC196MC device bits 10–12 are reserved. These bits are undefined.
Figure 5-14. PTS Service (PTSSRV) Register
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STANDARD AND PTS INTERRUPTS
5.6.2 Selecting the PTS Mode
The second byte of each PTSCB is always an 8-bit value called PTSCON. Bits 5–7 select the PTS
mode (Figure 5-15). The function of bits 0–4 differ for each PTS mode. Refer to the sections that
describe each mode in detail to see the function of these bits. Table 5-4 on page 5-12 lists the cycle
execution times for each PTS mode.
Address: PTSPCB + 1
PTSCON
The PTS control (PTSCON) register selects the PTS mode and sets up control functions for that
mode.
7
0
†
†
†
†
†
M2
M1
M0
Bit
Number
Bit
Mnemonic
Function
7:5
M2:0
PTS Mode
These bits select the PTS mode:
M2
0
M1
0
M0
0
block transfer
0
0
0
1
1
0
serial receive (MC, MD only)
reserved
0
1
1
1
0
0
1
0
1
serial transmit (MC, MD only)
single transfer
reserved
1
1
0
A/D scan
1
1
1
reserved
†
The function of this bit depends upon which mode is selected. See the PTS control block description
in each PTS mode section.
Figure 5-15. PTS Mode Selection Bits (PTSCON Bits 7:5)
5.6.3 Single Transfer Mode
In single transfer mode, an interrupt causes the PTS to transfer a single byte or word (selected by
the BW bit in PTSCON) from one memory location to another. This mode is typically used with
the EPA to move captured time values from the event-time register to internal RAM for further
processing. See AP-483, Application Examples Using the 8XC196MC/MD Microcontroller, for
application examples with code. Figure 5-16 shows the PTS control block for single transfer
mode.
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PTS Single Transfer Mode Control Block
In single transfer mode, the PTS control block contains a source and destination address (PTSSRC
and PTSDST), a control register (PTSCON), and a transfer count (PTSCOUNT).
7
0
0
8
0
8
0
0
0
Unused
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7
Unused
15
7
PTSDST (H)
PTSDST (L)
PTSSRC (H)
PTSSRC (L)
PTSCON
PTS Destination Address (high byte)
PTS Destination Address (low byte)
PTS Source Address (high byte)
PTS Source Address (low byte)
15
7
7
M2
M1
M0
BW
SU
DU
SI
DI
7
PTSCOUNT
Consecutive Byte or Word Transfers
Register
Location
PTSCB + 4 PTS Destination Address
Function
PTSDST
Write the destination memory location to this register. A valid address is
any unreserved memory location; however, it must point to an even
address if word transfers are selected.
PTSSRC
PTSCB + 2 PTS Source Address
Write the source memory location to this register. A valid address is any
unreserved memory location; however, it must point to an even address
if word transfers are selected.
Figure 5-16. PTS Control Block — Single Transfer Mode
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STANDARD AND PTS INTERRUPTS
PTS Single Transfer Mode Control Block (Continued)
Register
Location
Function
PTSCON
PTSCB + 1 PTS Control Bits
M2:0
PTS Mode
M2
M1
M0
1
0
0
single transfer mode
BW
Byte/Word Transfer
0 = word transfer
1 = byte transfer
SU†
Update PTSSRC
0 = reload original PTS source address after each byte or word
transfer
1 = retain current PTS source address after each byte or word
transfer
DU†
Update PTSDST
0 = reload original PTS destination address after each byte or
word transfer
1 = retain current PTS destination address after each byte or
word transfer
SI†
PTSSRC Autoincrement
0 = do not increment the contents of PTSSRC after each byte
or word transfer
1 = increment the contents of PTSSRC after each byte or word
transfer
DI†
PTSDST Autoincrement
0 = do not increment the contents of PTSDST after each byte
or word transfer
1 = increment the contents of PTSDST after each byte or word
transfer
PTSCOUNT PTSCB + 0 Consecutive Word or Byte Transfers
Defines the number of words or bytes that will be transferred during the
single transfer routine. Each word or byte transfer is one PTS cycle.
Maximum value is 255.
†
The DU/DI bits and SU/SI bits are paired in single transfer mode. Each pair must be set or cleared
together. However, the two pairs, DU/DI and SU/SI, need not be equal.
Figure 5-16. PTS Control Block — Single Transfer Mode (Continued)
The PTSCB in Table 5-5 defines nine PTS cycles. Each cycle moves a single word from location
20H to an external memory location. The PTS transfers the first word to location 6000H. Then it
increments and updates the destination address and decrements the PTSCOUNT register; it does
not increment the source address. When the second cycle begins, the PTS moves a second word
from location 20H to location 6002H. When PTSCOUNT equals zero, the PTS will have filled
locations 6000–600FH, and an end-of-PTS interrupt is generated.
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Table 5-5. Single Transfer Mode PTSCB
Unused
Unused
PTSDST (H) = 60H
PTSDST (L) = 00H
PTSSRC (H) = 00H
PTSSRC (L) = 20H
PTSCON = 85H (Mode = 100, BW = 0, SI/SU = 0, DI/DU = 1)
PTSCOUNT = 09H
5.6.4 Block Transfer Mode
In block transfer mode, an interrupt causes the PTS to move a block of bytes or words from one
memory location to another. See AP-483, Application Examples Using the 8XC196MC/MD Mi-
crocontroller, for application examples with code. Figure 5-17 shows the PTS control block for
block transfer modes.
In this mode, each PTS cycle consists of the transfer of an entire block of bytes or words. Because
a PTS cycle cannot be interrupted, the block transfer mode can create long interrupt latency. The
worst-case latency could be as high as 500 states, if you assume a block transfer of 32 words from
one external memory location to another, using an 8-bit bus with no wait states. See Table 5-4 on
page 5-12 for execution times of PTS cycles.
The PTSCB in Table 5-6 sets up three PTS cycles that will transfer five bytes from memory loca-
tions 20–24H to 6000–6004H (cycle 1), 6005–6009H (cycle 2), and 600A–600EH (cycle 3). The
source and destination are incremented after each byte transfer, but the original source address is
reloaded into PTSSRC at the end of each block-transfer cycle. In this routine, the PTS always gets
the first byte from location 20H.
Table 5-6. Block Transfer Mode PTSCB
Unused
PTSBLOCK = 05H
PTSDST (H) = 60H
PTSDST (L) = 00H
PTSSRC (H) = 00H
PTSSRC (L) = 20H
PTSCON = 17H (Mode = 000; DI, SI, DU, BW = 1; SU = 0)
PTSCOUNT = 03H
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STANDARD AND PTS INTERRUPTS
PTS Block Transfer Mode Control Block
In block transfer mode, the PTS control block contains a block size (PTSBLOCK), a source and
destination address (PTSSRC and PTSDST), a control register (PTSCON), and a transfer count
(PTSCOUNT).
7
0
0
8
0
8
0
0
0
Unused
0
0
0
0
0
0
0
0
7
PTSBLOCK
PTSDST (H)
PTSDST (L)
PTSSRC (H)
PTSSRC (L)
PTSCON
PTS Block Size
15
7
PTS Destination Address (high byte)
PTS Destination Address (low byte)
PTS Source Address (high byte)
PTS Source Address (low byte)
15
7
7
M2
M1
M0
BW
SU
DU
SI
DI
7
PTSCOUNT
Consecutive Block Transfers
Register
Location
Function
PTSBLOCK PTSCB + 6 PTS Block Size
Specifies the number of bytes or words in each block. Valid values are
1–32, inclusive.
PTSDST
PTSSRC
PTSCB + 4 PTS Destination Address
Write the destination memory location to this register. A valid address is
any unreserved memory location; however, it must point to an even
address if word transfers are selected.
PTSCB + 2 PTS Source Address
Write the source memory location to this register. A valid address is any
unreserved memory location; however, it must point to an even address
if word transfers are selected.
Figure 5-17. PTS Control Block — Block Transfer Mode
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PTS Block Transfer Mode Control Block (Continued)
Register
Location
Function
PTSCON
PTSCB + 1 PTS Control Bits
M2:0
PTS Mode
These bits select the PTS mode:
M2
M1
M0
0
0
0
block transfer mode
BW
SU
Byte/Word Transfer
0 = word transfer
1 = byte transfer
Update PTSSRC
0 = reload original PTS source address after each block
transfer is complete
1 = retain current PTS source address after each block transfer
is complete
DU
SI
Update PTSDST
0 = reload original PTS destination address after each block
transfer is complete
1 = retain current PTS destination address after each block
transfer is complete
PTSSRC Autoincrement
0 = do not increment the contents of PTSSRC after each byte
or word transfer
1 = increment the contents of PTSSRC after each byte or word
transfer
DI
PTSDST Autoincrement
0 = do not increment the contents of PTSDST after each byte
or word transfer
1 = increment the contents of PTSDST after each byte or word
transfer
PTSCOUNT PTSCB + 0 Consecutive Block Transfers
Defines the number of blocks that will be transferred during the block
transfer routine. Each block transfer is one PTS cycle. Maximum number
is 255.
Figure 5-17. PTS Control Block — Block Transfer Mode (Continued)
5.6.5 A/D Scan Mode
In the A/D scan mode, the PTS causes the A/D converter to perform multiple conversions on one
or more channels and then stores the results in a table in memory. Figure 5-19 shows the PTS con-
trol block for A/D scan mode.
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STANDARD AND PTS INTERRUPTS
PTS A/D Scan Mode Control Block
In A/D scan mode, the PTS causes the A/D converter to perform multiple conversions on one or more
channels and then stores the results. The control block contains pointers to both the AD_RESULT
register (PTSPTR1) and a table of A/D conversion commands and results (PTSPTR2), a control
register (PTSCON), and an A/D conversion count (PTSCOUNT).
7
0
Unused
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7
0
8
0
8
0
0
0
Unused
15
7
PTSPTR2 (H)
PTSPTR2 (L)
PTSPTR1 (H)
PTSPTR1 (L)
PTSCON
Pointer 2 Value (high byte)
Pointer 2 Value (low byte)
Pointer 1 Value (high byte)
Pointer 1 Value (low byte)
15
7
7
M2
M1
M0
0
UPDT
0
1
0
7
PTSCOUNT
Consecutive A/D Conversions
Register
Location
PTSCB + 4 Pointer 2 Value
Function
PTSPTR2
This register contains the address of the A/D result register
(AD_RESULT).
PTSPTR1
PTSCON
PTSCB + 2 Pointer 1 Value
This register contains the address of the table of A/D conversion
commands and results.
PTSCB + 1 PTS Control Bits
M2:0 PTS Mode
These bits select the PTS mode.
M2
M1
M0
1
1
0
A/D Scan Mode
UPDT Update
0 = reload original PTSPTR1 value after each A/D scan
1 = retain current PTSPTR1 value after each A/D scan
Figure 5-18. PTS Control Block – A/D Scan Mode
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PTS A/D Scan Mode Control Block (Continued)
PTSCOUNT PTSCB + 0 Consecutive A/D Conversions
Defines the number of A/D conversions that will be completed during the
A/D scan routine. Each cycle consists of the PTS transferring the A/D
conversion results into the command/data table, and then loading a new
command into the AD_COMMAND register. Maximum number is 255.
Figure 5-18. PTS Control Block – A/D Scan Mode (Continued)
To use the A/D scan mode, you must first set up a command/data table in memory (Table 5-7).
The command/data table contains A/D commands that are interleaved with blank memory loca-
tions. The PTS stores the conversion results in these blank locations. Only the amount of available
memory limits the table size; it can reside in internal or external RAM.
Table 5-7. A/D Scan Mode Command/Data Table
Address
Contents
XXXX + AH
XXXX + 8H
XXXX + 6H
XXXX + 4H
XXXX + 2H
XXXX
A/D Result 2
Unused
Unused
Unused
A/D Command 3†
A/D Result 1
A/D Command 2
A/D Result 0††
A/D Command 1
†
Write 0000H to prevent a new conversion at the end of the
routine.
††
Result of the A/D conversion that initiated the PTS routine.
To initiate A/D scan mode, enable the A/D conversion complete interrupt and assign it to the PTS.
Software must initiate the first conversion. When the A/D finishes the first conversion and gen-
erates an A/D conversion complete interrupt, the interrupt vectors to the PTSCB and initiates the
A/D scan routine. The PTS stores the conversion results, loads a new command into
AD_COMMAND, and then decrements the number in PTSCOUNT. As each additional conver-
sion complete interrupt occurs, the PTS repeats the A/D scan cycle; it stores the conversion re-
sults, loads the next conversion command into the AD_COMMAND register, and decrements
PTSCOUNT. The routine continues until PTSCOUNT decrements to zero. When this occurs,
hardware clears the enable bit in the PTSSEL register, which disables PTS service, and sets the
PTSSRV bit, which requests an end-of-PTS interrupt.
The interrupt service routine could process the conversion results and then re-enable PTS service
for the A/D conversion complete interrupt. Because the lower six bits of the AD_RESULT regis-
ter contain status information, the end-of-PTS interrupt service routine could shift the results data
to the right six times to leave only the conversion results in the memory locations. See AP-483,
Application Examples Using the 8XC196MC/MD Microcontroller, for application examples with
code.
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STANDARD AND PTS INTERRUPTS
5.6.5.1
A/D Scan Mode Cycles
Software must start the first A/D conversion. After the A/D conversion complete interrupt ini-
tiates the PTS routine, the following actions occur.
1. The PTS reads the first command (from address XXXX), stores it in a temporary location,
and increments the PTSPTR1 register twice. PTSPTR1 now points to the first blank
location in the command/data table (address XXXX + 2).
2. The PTS reads the AD_RESULT register, stores the results of the first conversion into
location XXXX + 2 in the command/data table, and increments the PTSPTR1 register
twice. PTSPTR1 now points to XXXX + 4.
3. The PTS loads the command from the temporary location into the AD_COMMAND
register. This completes the first A/D scan cycle and initiates the next A/D conversion.
4. If UPDT (PTSCON.3) is clear, the original address is reloaded into the PTSPTR1 register.
The next cycle uses the same command and overwrites previous data. If UPDT is set, the
updated address remains in PTSPTR1 and the next cycle uses a new command and stores
the conversion results at the new address.
5. PTSCOUNT is decremented and the CPU returns to regular program execution. When the
next A/D conversion complete interrupt occurs, the cycle repeats. When PTSCOUNT
reaches zero, hardware clears the corresponding PTSSEL bit and sets the PTSSRV bit,
which requests the end-of-PTS interrupt.
5.6.5.2
A/D Scan Mode Example 1
The command/data table shown in Table 5-8 sets up a series of A/D conversions, beginning with
channel 7 and ending with channel 4. Each table entry is a word (two bytes). Table 5-9 shows the
corresponding PTSCB.
Software starts a conversion on channel 7. Upon completion of the conversion, the A/D conver-
sion complete interrupt initiates the A/D scan mode routine. Step 1 stores the channel 6 command
in a temporary location and increments PTSPTR1 to 3002H. Step 2 stores the result of the channel
7 conversion in location 3002H and increments PTSPTR1 to 3004H. Step 3 loads the channel 6
command from the temporary location into the AD_COMMAND register to start the next con-
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version. Step 4 updates PTSPTR1 (PTSPTR1 now points to 3004H) and step 5 decrements
PTSCOUNT to 3. The next cycle begins by storing the channel 5 command in the temporary lo-
cation. During the last cycle (PTSCOUNT = 1), the dummy command is loaded into the
AD_COMMAND register and no conversion is performed. PTSCOUNT is decremented to zero
and the end-of-PTS interrupt is requested.
Table 5-8. Command/Data Table (Example 1)
Address
Contents
300EH
300CH
300AH
3008H
3006H
3004H
3002H
3000H
AD_RESULT for ACH4
Unused
Unused
Unused
Unused
0000H (Dummy command)
AD_RESULT for ACH5
AD_COMMAND for ACH4
AD_RESULT for ACH6
AD_COMMAND for ACH5
AD_RESULT for ACH7
AD_COMMAND for ACH6
Table 5-9. A/D Scan Mode PTSCB (Example 1)
Unused
Unused
PTSPTR2 (H) = 1FH
PTSPTR2 (L) = AAH
PTSPTR1 (H) = 30H
PTSPTR1 (L) = 00H
PTSCON = CBH (Mode = 110, UPDT = 1)
PTSCOUNT = 04H
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STANDARD AND PTS INTERRUPTS
5.6.5.3
A/D Scan Mode Example 2
Table 5-11 sets up a series of ten PTS cycles, each of which reads a single A/D channel and stores
the result in a single location (3002H). The UPDT bit (PTSCON.3) is cleared so that original con-
tents of PTSPTR1 are restored after the cycle. The command/data table is shown in Table 5-10.
Table 5-10. Command/Data Table (Example 2)
Address
Contents
3002H
3000H
AD_RESULT for ACHx
Unused
AD_COMMAND for ACHx
Table 5-11. A/D Scan Mode PTSCB (Example 2)
Unused
Unused
PTSPTR2 (H) = 1FH
PTSPTR2 (L) = AAH
PTSPTR1 (H) = 30H
PTSPTR1 (L) = 00H
PTSCON = C3H (Mode = 110, UPDT = 0)
PTSCOUNT = 0AH
Software starts a conversion on channel x. When the conversion is finished and the A/D conver-
sion complete interrupt is generated, the A/D scan mode routine begins. The PTS reads the com-
mand in location 3000H and stores it in a temporary location. Then it increments PTSPTR1 twice
and stores the value of the AD_RESULT register in location 3002H. The final step is to copy the
conversion command from the temporary location to the AD_COMMAND register. The CPU
could process or move the conversion results data from the table before the next conversion com-
pletes and a new PTS cycle begins. When the next cycle begins, PTSPTR1 again points to 3000H
and the repeats the events of the first cycle. The value of the AD_RESULT register is written to
location 3002H and the command at location 3000H is re-executed.
5.6.6 Serial I/O Modes
The 8XC196MH has a two-channel serial I/O port. The 8XC196MC and MD have no serial I/O
ports, but the serial I/O modes of the PTS provide a software serial I/O channel for both synchro-
nous and asynchronous transfers and receptions. There are four basic modes of operation: syn-
chronous transmit, synchronous receive, asynchronous transmit, and asynchronous receive. A
standard I/O port signal is configured to function as either the transmit data (TXD) or receive data
(RXD) signal and an EPA channel sets the baud rate. You may configure any port 2 signal (MC
and MD) or P7.3:0 (MD) as TXD or RXD. In the synchronous modes, an EPA channel can either
generate the serial clock (SCK) signal or input an external clock signal. Up to 16 bits may be
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8XC196MC, MD, MH USER’S MANUAL
transmitted or received including the parity and stop bits in the asynchronous modes. The serial
I/O modes require two PTS control blocks to configure all options (see Figures 5-19 and 5-20).
These blocks need not be contiguous, but they must each be located in register RAM on a quad-
word boundary. See AP-483, Application Examples Using the 8XC196MC/MD Microcontroller,
for application examples with code.
PTS Serial I/O Mode Control Block 1
(8XC196MC, MD)
The PTS control block 1 contains pointers to both the second PTS control block (PTSVEC) and the
EPA time register that sets the baud rate (EPAREG). It also contains a 16-bit value that is used to
calculate the baud rate, a control register (PTSCON), and a consecutive PTS cycle count
(PTSCOUNT).
15
8
0
8
0
8
0
0
0
PTSVEC (H)
PTSVEC (L)
BAUD (H)
SIO PTSCB2 Base Address Pointer (high byte)
SIO PTSCB2 Base Address Pointer (low byte)
Baud Value (high byte)
7
15
7
BAUD (L)
Baud Value (low byte)
15
7
EPAREG (H)
EPAREG (L)
PTSCON
EPA Time Register Address (high byte)
EPA Time Register Address (low byte)
7
M2
M1
M0
SA1
0
0
SA0
MAJ
7
PTSCOUNT
Consecutive PTS Cycles
Register
Location
Function
PTSVEC
PTSCB1 + 6
SIO PTSCB2 Base Address Pointer
This register contains the base address of the second PTS
control block for serial I/O mode.
Figure 5-19. PTS Control Block 1 – Serial I/O Mode
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STANDARD AND PTS INTERRUPTS
PTS Serial I/O Mode Control Block 1 (Continued)
(8XC196MC, MD)
Register
BAUD
Location
Function
PTSCB1 + 4
Baud Value
This register contains the 16-bit value that the PTS uses to
generate the desired baud rate. Use the following formula to
calculate the value to load into the BAUD register.
FXTAL1
----------------------------------------------------------------------------------------------------------------
Baud_value =
Multiplier (Baud_rate × EPA_prescale)
where:
Baud_value
is a 16-bit integer that is loaded into the
BAUD register
FXTAL1
is the input frequency on XTAL1, in MHz
Multiplier
is the number 4 in asynchronous modes and
the number 8 in synchronous modes
Baud_rate
is the desired baud rate, in bits per second
EPA_prescale is the EPA timer prescale number, 1–64
EPA Time Register Address
EPAREG
PTSCON
PTSCB1 + 2
PTSCB1 + 2
This register contains the 16-bit address of the EPAx_TIME or
COMPx_TIME register.
PTS Control Bits
M2:0
PTS Mode
M2
0
0
M1
0
1
M0
1
1
SIO Receive Mode
SIO Transmit Mode
SA1:0 Asynchronous, Synchronous Mode Select
SA1 SA0†
0
0
enables the asynchronous serial I/O
modes
1
1
enables the synchronous serial I/O
modes
†
Always write the same value to both bits.
MAJ
Majority Sampling
0 = disable majority sampling in asynchronous receive
mode; always clear in all other modes
1= enable majority sampling in asynchronous receive
mode
Figure 5-19. PTS Control Block 1 – Serial I/O Mode (Continued)
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PTS Serial I/O Mode Control Block 1 (Continued)
(8XC196MC, MD)
Register
Location
Function
PTSCOUNT PTSCB1 + 0
Consecutive PTS Cycles
Defines the number of bits to be transmitted or received,
including parity and stop bits, but not the start bit. For
asynchronous modes, program a number that is between 1–16.
For synchronous modes, program a number that is twice the
number of bits to be transmitted or received (2–32). PTSCOUNT
is decremented at the end of each PTS cycle. When it reaches
zero, hardware clears the corresponding PTSSEL bit and sets
the PTSSRV bit, which requests the end-of-PTS interrupt.
Figure 5-19. PTS Control Block 1 – Serial I/O Mode (Continued)
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STANDARD AND PTS INTERRUPTS
PTS Serial I/O Mode Control Block 2
(8XC196MC, MD)
The PTS control block 2 contains pointers to both the port register (PORTREG) and the data register
(DATA). It also contains a 16-bit value that is used to calculate the sample time for asynchronous
receptions when majority sampling is selected (SAMPTIME), a control register (PTSCON1), and a 16-
bit value that is used to select the port signal that functions as the TXD or RXD signal (PORTMASK).
7
0
Unused
0
0
0
0
0
0
0
0
7
0
8
0
0
0
SAMPTIME
Sample Time Value
Data Register (high byte)
Data Register (low byte)
15
7
DATA (H)
DATA (L)
7
PTSCON1 (Synch)
PTSCON1 (Asynch)
PORTMASK
PORTREG (H)
PORTREG (L)
0
0
0
0
0
0
0
0
0
0
TRC
FE
0
7
RPAR
PEN
TPAR
7
0
Port Mask Register
15
7
0
0
Port Address Pointer (high byte)
Port Address Pointer (low byte)
Register
Location
Function
SAMPTIME PTSCB2 + 6
Sample Time Value
This register controls the time between samples during
asynchronous receive mode when majority sampling is selected.
Use the following formula to calulate the value to load into the
SAMPTIME register.
TSAM × FXTAL1
------------------------------------------
Sample_time =
where:
– 9
2
Sample_time is an integer, 1–31, that is loaded into the
SAMPTIME register
TSAM
is the desired time between samples, in µs
is the input frequency on XTAL1, in MHz
FXTAL1
Figure 5-20. PTS Control Block 2 – Serial I/O Mode
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PTS Serial I/O Mode Control Block 2 (Continued)
(8XC196MC, MD)
Register
DATA
Location
PTSCB2 + 4
Function
Data Register
This 16-bit register holds the data to be transmitted or the data
that has been received. During transmit mode, the least-
significant bit (bit 0) is transmitted first. Data shifts to the right
with each successive transmission. During receive mode, the
first bit is loaded into the most-significant bit (bit 15). Data shifts
to the right with each successive reception.
PTSCON1
PTSCB2 + 3
PTS Control Bits
Synchronous Mode
TRC
Transmit/Receive Control
0 = transmit or receive data during even numbered
PTS cycles
1 = transmit or receive data during odd numbered PTS
cycles
Initialize this bit at the start of every transmission or
reception.
Asynchronous Mode
RPAR
Receive Parity Control and Status
Initialize this bit as indicated before beginning a
reception.
0 = TPAR bit is set to select even parity
1 = TPAR bit is cleared to select odd parity
If this bit is set at the end of a reception, a parity error
has occurred.
PEN
FE
Parity Enable
0 = disble parity
1 = enable parity
Framing Error Flag
0 = stop bit was 1
1 = stop bit was 0
Clear this bit at the start of every reception.
Transmit Parity Control
TPAR
0 = even parity
1 = odd parity
Figure 5-20. PTS Control Block 2 – Serial I/O Mode (Continued)
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STANDARD AND PTS INTERRUPTS
PTS Serial I/O Mode Control Block 2 (Continued)
(8XC196MC, MD)
Register
Location
Function
PORTMASK PTSCB2 + 2
Port Mask Register
Select the port signal that will function as the transmit data (TXD)
or receive data (RXD) signal by setting the corresponding bit.
Clear all other bits to mask those signals.
PORTREG
PTSCB2 + 0
Port Address Pointer
This 16-bit register contains the address of the port that will be
used to transmit or receive data.
Figure 5-20. PTS Control Block 2 – Serial I/O Mode (Continued)
Synchronous SIO Transmit Mode Example
5.6.6.1
In synchronous serial I/O (SSIO) transmit mode, an EPA channel controls the transmission baud
rate by generating or capturing a serial clock signal (SCK). To generate the SCK signal, configure
the EPA channel in compare mode and set the output-pin toggle option. Whenever a match occurs
between the EPA event-time register and a timer register, the EPA channel toggles SCK and gen-
erates an interrupt. If an external source will provide the SCK signal, configure the EPA channel
in capture mode with capture on either edge set. In this case, the EPA channel generates an inter-
rupt whenever the SCK input toggles. On every other EPA interrupt, the PTS shifts a data bit out
onto a port pin that is configured to function as the Transmit Data signal (TXD). PTSCON1 (Fig-
ure 5-19 on page 5-38) controls whether the transmission occurs on even or odd PTS cycles. Be-
cause transmissions occur only on a rising or falling clock edge, two PTS cycles occur for every
one data bit transmission (Figure 5-21). It takes 16 PTS cycles to transmit eight data bits. In SSIO
transmit mode, only data bits can be transmitted; parity and stop bits are not included.
End-of-PTS
Conventional
16 PTS Serviced Interrupts
Interrupt
Interrupts
SCK
TXD
(Port pin)
Bit 0
LSB
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
MSB
A3120-01
Figure 5-21. Synchronous SIO Transmit Mode Timing
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If the SCK signal is generated by the EPA channel, the first PTS cycle must be started manually.
• Initialize the TXD port pin and the SCK signal to the system-required logic level before
starting a transmission.
• Add the contents of the timer register to the Baud_value (Figure 5-19 on page 5-38) and
store the result into the EPA time register. This sets up the timing for the first interrupt and
causes the first bit transmission to occur at the proper baud rate.
The following example uses EPA0 to control the baud rate and output the SCK signal and P2.2
to output the data (TXD). It sets up a synchronous serial I/O PTS routine that transmits 16 bytes
with eight data bits at 9600 baud. This example uses several user-defined registers. T_COUNT
defines the number of bytes to transfer and TXDDONE is a flag that is set when all bytes are
transferred.
1. Disable the interrupts and the PTS.
— Use the DI instruction to disable all standard interrupts and the DPTS instruction to
disable the PTS.
2. Set-up the stack pointer.
3. Reset all interrupt mask registers.
— Clear INT_MASK, INT_MASK1and PI_MASK.
4. Initialize P2.0 to function as the EPA0 output (SCK) and P2.2 to function as TXD.
— Clear P2_DIR (selects output).
— Set P2_MODE.0 (selects special function).
— Clear P2_MODE.2 (selects LSIO function).
— Set P2_REG bits 0 and 2 (initializes TXD and SCK outputs to “1”).
5. Initialize and enable the timer. Select up counting, internal clock, and prescaler disabled.
— Set T1CONTROL bits 6 and 7 (Figure 11-8 on page 11-16).
6. Initialize the PTSCB as shown in Table 5-13.
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STANDARD AND PTS INTERRUPTS
Table 5-13. SSIO Transmit Mode PTSCBs
PTSCB1
PTSCB2
PTSVEC (H) = pointer to PTSCB2
PTSVEC (L) = pointer to PTSCB2
BAUD (H) = 00H (9600 baud at 16 MHz)
BAUD (L) = D0H (9600 baud at 16 MHz)
EPAREG (H) = 1FH (EPA0_TIME)
EPAREG (L) = 42H (EPA0_TIME)
PTSCON = 72H (SSIO transmit mode)
PTSCOUNT = 10H (8 data bits x 2)
Unused
SAMPTIME = unused
DATA (H) = unused
DATA (L) = nnH (8 data bits)
PTSCON1 = 02H (transmit data on odd PTS cycles)
PORTMASK = 04H (P2.2 = TXD)
PORTREG (H) = 1FH (P2_REG)
PORTREG (L) = D4H (P2_REG)
7. Enable EPA0 interrupt.
— Set INT_MASK.2.
8. Load the number of bytes to transmit into the user_defined transmit count register
(T_COUNT) and clear the user-defined transfer-done flag (TXDDONE).
— LD T_COUNT, #16
— CLRB TXDDONE
9. Select PTS service for EPA0.
— Set PTSSEL.2.
10. Set-up EPA0 as a compare-only channel.
— Set EPA0_CON.6 (Figure 11-10 on page 11-19).
11. Start the operation of the EPA0 channel by writing the time of the first interrupt to
EPA0_TIME. To set-up the correct value, add the baud_value (0D0H) to the current
TIMER1 value and store the result in EPA0_TIME. The baud_value determines the time
to the first PTS interrupt and the first transition on SCK. The PTS transmits the first data
bit on first transition of SCK in this example. The baud_value of 0D0H selects a baud rate
of 9600.
12. Enable the PTS and conventional interrupts.
— Use the EI instruction to enable all standard interrupts and the EPTS instruction to
enable the PTS.
13. The transmission will begin. Data is shifted out with the least-significant (rightmost) bit
first. Each time a timer match occurs between EPA0_TIME and TIMER1, the EPA0
channel generates an interrupt and toggles the SCK signal. The PTS outputs the next bit of
data on the pin configured as TXD on odd PTS cycles. When PTSCOUNT decrements to
zero, the PTS calls the end-of-PTS interrupt (Figure 5-22). The interrupt service routine
should disable the EPA channel because the final PTS cycle loads the next SCK toggle
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8XC196MC, MD, MH USER’S MANUAL
time into the event-time register. If this toggle occurs, the clock polarity will change
because of the odd number of toggles and erroneous data may be output. The interrupt
service routine should also load the next data byte, reload the PTSCOUNT and PTSCON1
registers, select PTS service for EPA0, reload both the EPA0_CONTROL and
EPA0_TIME registers.
14. To determine when all bytes have been transmitted, create a loop routine to check the
status of the TXDDONE flag.
End-Of-PTS Interrupt
Save Critical Data
Disable EPA Channel
Clear Interrupt Request Bit
T_COUNT = T_COUNT - 1
Y
T_COUNT = 0?
N
Set-up next data transfer
- Load next data byte into DATA register
- Reload PTSCOUNT and PTSCON1 registers
- Select PTS service for EPA channel
- Re-initialize the EPA channel
TXDDONE = 1
- Re-initialize the EPA timer to initiate first bit transfer
Load Critical Data
Return
A3274-01
Figure 5-22. Synchronous SIO Transmit Mode — End-of-PTS Interrupt Routine Flowchart
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STANDARD AND PTS INTERRUPTS
5.6.6.2
Synchronous SIO Receive Mode Example
In synchronous serial I/O (SSIO) receive mode, an EPA channel controls the reception baud rate
by generating or capturing a serial clock signal (SCK). To generate the SCK signal, configure the
EPA channel in compare mode and set the output-pin toggle option. Whenever a match occurs
between the EPA event-time register and a timer register, the EPA channel toggles SCK and gen-
erates an interrupt. If an external source will provide the SCK signal, configure the EPA channel
in capture mode with capture on either edge set. In this case, the EPA channel generates an inter-
rupt whenever the SCK input toggles. On every other EPA interrupt, the PTS inputs a data bit
from a port pin that is configured to function as the Receive Data signal (RXD). PTSCON1 (Fig-
ure 5-19 on page 5-38) controls whether the reception occurs on even or odd PTS cycles. Because
receptions occur only on a rising or falling clock edge, two PTS cycles occur for every one data
bit reception (Figure 5-23). It takes 16 PTS cycles to receive eight data bits. SSIO receptions do
not include parity or stop bits.
End-of-PTS
Conventional
16 PTS Serviced Interrupts
Interrupt
Interrupts
SCK
Input Data Sampled on Rising Clock Edge
RXD
Bit 0
LSB
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
MSB
(Port pin)
A3121-01
Figure 5-23. Synchronous SIO Receive Timing
If the SCK signal is generated by the EPA channel, the first PTS cycle must be started manually.
• Initialize the RXD port pin and the SCK signal to the system-required logic level before
starting a reception.
• Add the contents of the timer register to the Baud_value (Figure 5-19 on page 5-38) and
store the result into the EPA time register. This sets up the timing for the first interrupt and
causes the first interrupt to occur at the proper baud rate.
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The following example uses EPA0 to capture the SCK signal and P2.3 to receive the data (RXD).
It sets up a synchronous serial I/O PTS routine that receives 16 bytes with eight data bits. Because
this example uses an external serial clock input, the TIMER1 and BAUD registers are not used.
The external clock source controls the baud rate. This example uses several user-defined regis-
ters. R_COUNT defines the number of bytes to receive and RXDDONE is a flag that is set when
all bytes are received.
1. Disable the interrupts and the PTS.
— Use the DI instruction to disable all standard interrupts and the DPTS instruction to
disable the PTS.
2. Set-up the stack pointer.
3. Reset all interrupt mask registers.
— Clear INT_MASK, INT_MASK1and PI_MASK.
4. Initialize P2.0 to function as the EPA0 input (SCK) and P2.3 to function as RXD.
— Set P2_DIR bits 0 and 3 (selects input).
— Set P2_MODE.0 (selects special function).
— Clear P2_MODE.3 (selects LSIO function).
— Set P2_REG bits 0 and 3 (initializes SCK and RXD input to “1”).
5. Initialize the PTSCB as shown in Table 5-14.
Table 5-14. SSIO Receive Mode PTSCBs
PTSCB1
PTSCB2
PTSVEC (H) = pointer to PTSCB2
PTSVEC (L) = pointer to PTSCB2
BAUD (H) = unused
Unused
SAMPTIME = unused
DATA (H) = unused
BAUD (L) = unused
DATA (L) = 00H (clear register to receive data)
PTSCON1 = 00H (receive data on even PTS cycles)
PORTMASK = 08H (P2.3 = RXD)
PORTREG (H) = 1FH (P2_REG)
PORTREG (L) = D4H (P2_REG)
EPAREG (H) = 1FH (EPA0_TIME)
EPAREG (L) = 42H (EPA0_TIME)
PTSCON = 32H (SSIO receive mode)
PTSCOUNT = 10H (8 data bits x 2)
6. Enable EPA0 interrupt.
— Set INT_MASK.2.
7. Load the number of bytes to transmit into the user_defined transmit count register
(R_COUNT) and clear the user-defined reception-done flag (RXDDONE).
— LD R_COUNT, #16
— CLRB RXDDONE
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STANDARD AND PTS INTERRUPTS
8. Select PTS service for EPA0.
— Set PTSSEL.2.
9. Set-up EPA0 to capture on both rising and falling edges.
— Set EPA0_CON bits 4 and 5 (Figure 11-10 on page 11-19).
10. Enable the PTS and conventional interrupts.
— Use the EI instruction to enable all standard interrupts and the EPTS instruction to
enable the PTS.
11. Toggle the SCK input to start the reception. Data is shifted into the most-significant
(leftmost) bit first and shifts right with each successive bit received. The EPA generates an
interrupt each time that the SCK input toggles. The PTS receives the next bit of data on the
pin configured as RXD on even PTS cycles. When PTSCOUNT decrements to zero, the
PTS calls the end-of-PTS interrupt (Figure 5-24). The interrupt service routine should
disable the EPA channel, clear the DATA register, reload the PTSCOUNT and PTSCON1
registers, reload EPA0_CON, and select PTS service for EPA0. If the EPA were generating
the SCK signal, the end-of-PTS interrupt service routine would also have to reload the
EPA0_TIME register.
12. To determine when all bytes have been transmitted, create a loop routine to check the
status of the RXDDONE flag.
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End-Of-PTS Interrupt
Save Critical Data
Disable EPA Channel
Clear Interrupt Request Bit
Save Received Data
R_COUNT = R_COUNT - 1
Y
R_COUNT = 0?
N
Set-up next data reception
- Clear DATA register
- Reload PTSCOUNT and PTSCON1 registers
- Select PTS service for EPA channel
- Re-initialize the EPA channel
RXDDONE = 1
Load Critical Data
Return
A3275-01
Figure 5-24. Synchronous SIO Receive Mode — End-of-PTS Interrupt Routine Flowchart
5.6.6.3 Asynchronous SIO Transmit Mode Example
In asynchronous serial I/O (ASIO) transmit mode, an EPA channel controls the transmission baud
rate by generating an interrupt whenever a match occurs between the EPA event-time register and
a timer register. The PTS shifts a data bit out onto a port pin that is configured to function as the
Transmit Data signal (TXD) when the selected EPA channel generates a compare interrupt (Fig-
ure 5-25). In ASIO transmit mode, the PTS automatically transmits up to 16 bits (data + 1 optional
parity + 1 stop bit). The maximum number of data bits is 14 with parity, or 15 without.
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STANDARD AND PTS INTERRUPTS
End-of-PTS
Conventional
Interrupt
10 PTS Serviced Interrupts
Interrupts
Software Clears TXD
LSB
MSB
Parity
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Start
Stop
TXD
(Port pin)
1 Bit Time
Optional
Parity Bit
A3119-01
Figure 5-25. Asynchronous SIO Transmit Timing
The first PTS cycle must be started manually by generating a start bit and then setting up the tim-
ing for the first EPA interrupt.
• Initialize the TXD port pin to one before starting a transmission.
• Write a zero to the TXD port pin to start the transmission. The PTS uses this as the start bit.
• Add the contents of the timer register to the Baud_value (Figure 5-19 on page 5-38) and
store the result into the EPA time register. This sets up the timing for the first interrupt and
causes the first bit transmission to occur at the proper baud rate.
The following example uses P2.0 to output the data (TXD) and EPA0 to control the baud rate. It
sets up an asynchronous serial I/O PTS routine that transmits 16 bytes with eight data bits, one
parity bit, and one stop bit at 9600 baud. This example uses several user-defined registers.
T_COUNT defines the number of bytes to transfer and TXDDONE is a flag that is set when all
bytes are transferred.
1. Disable the interrupts and the PTS.
— Use the DI instruction to disable all standard interrupts and the DPTS instruction to
disable the PTS.
2. Set-up the stack pointer.
3. Reset all interrupt mask registers.
— Clear INT_MASK, INT_MASK1and PI_MASK.
4. Initialize P2.0 to function as TXD.
— Clear P2_DIR.0 (selects output).
— Clear P2_MODE.0 (selects LSIO function).
— Set P2_REG.0 (initializes TXD output to “1”).
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5. Initialize and enable the timer; select up counting, internal clock, and prescaler disabled.
— Set T1CONTROL bits 6 and 7 (Figure 11-8 on page 11-16).
6. Initialize the PTSCB as shown in Table 5-15.
Table 5-15. ASIO Transmit Mode PTSCBs
PTSCB1
PTSCB2
PTSVEC (H) = pointer to PTSCB2
PTSVEC (L) = pointer to PTSCB2
BAUD (H) = 01H (9600 baud at 16 MHz)
BAUD (L) = A0H (9600 baud at 16 MHz)
EPAREG (H) = 1FH (EPA0_TIME)
EPAREG (L) = 42H (EPA0_TIME)
PTSCON = 60H (ASIO transmit mode)
Unused
SAMPTIME = unused
DATA (H) = unused
DATA (L) = nnH (8 data bits)
PTSCON1 = 21H (enable odd parity)
PORTMASK = 01H (P2.0 = TXD)
PORTREG (H) = 1FH (P2_REG)
PORTREG (L) = D4H (P2_REG)
PTSCOUNT = 0AH (8 data bits, 1 parity, & 1 stop
bit)
7. Enable EPA0 interrupt.
— Set INT_MASK.2.
8. Load the number of bytes to transmit into the user_defined transmit count register
(T_COUNT) and clear the user-defined transfer-done flag (TXDDONE).
— LD T_COUNT, #16
— CLRB TXDDONE
9. Select PTS service for EPA0.
— Set PTSSEL.2.
10. Set-up the transmission start bit.
— Clear P2.0.
11. Set-up EPA0 as a compare-only channel.
— Set EPA0_CON.6 (Figure 11-10 on page 11-19).
12. Start the operation of the EPA0 channel by writing the time of the first interrupt to
EPA0_TIME. To set-up the correct value, add the baud_value (1A0H) to the current
TIMER1 value and store the result in EPA0_TIME. The baud_value determines the time
to the first PTS interrupt. When the interrupt occurs, the PTS transmits the first data bit.
The baud_value of 1A0H selects a baud rate of 9600.
13. Enable the PTS and conventional interrupts.
— Use the EI instruction to enable all standard interrupts and the EPTS instruction to
enable the PTS.
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STANDARD AND PTS INTERRUPTS
14. The transmission will begin. Data is shifted out with the least-significant (rightmost) bit
first. Each time a timer match occurs between EPA0_TIME and TIMER1, the EPA0
channel generates an interrupt and the PTS outputs the next bit of data on the pin
configured as TXD. When PTSCOUNT decrements to zero, the PTS calls the end-of-PTS
interrupt (Figure 5-26). The interrupt service routine should load the next data byte, reload
the PTSCOUNT and PTSCON1 registers, clear the TXD bit to create the start bit for the
next word to be transmitted, select PTS service for EPA0, and reload both the
EPA0_CONTROL and EPA0_TIME registers.
15. To determine when all bytes have been transmitted, create a loop routine to check the
status of the TXDDONE flag.
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End-Of-PTS Interrupt
Save Critical Data
Is PTS
N
Cycle Completed?
Y
Disable EPA Channel
Clear Interrupt Request Bit
T_COUNT = T_COUNT - 1
Y
T_COUNT = 0?
N
Set-up next data transfer
- Load next data byte into DATA register
- Reload PTSCOUNT and PTSCON1 registers
- Create start bit (clear TXD)
- Select PTS service for EPA channel
- Re-initialize the EPA channel
TXDDONE = 1
- Re-initialize the EPA timer to initiate first bit transfer
Load Critical Data
Return
A3276-01
Figure 5-26. Asynchronous SIO Transmit Mode — End-of-PTS Interrupt Routine Flowchart
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STANDARD AND PTS INTERRUPTS
5.6.6.4
Asynchronous SIO Receive Mode Example
In asynchronous serial I/O (ASIO) receive mode, an EPA channel is set up to capture the falling
edge when the data start bit toggles on a port pin that is configured to function as the Receive Data
signal (RXD). When the capture occurs, the EPA generates a conventional interrupt which starts
the asynchronous receive process. This conventional interrupt service routine would be the same
as the end-of-PTS interrupt service routine. It changes the EPA channel to the compare mode and
sets the time of the next compare to 1.5 bit times and enables the PTS. At exactly 1.5 bit times
from the beginning of the start bit, the first PTS cycle samples the input data on RXD and shifts
it into the DATA register (Figure 5-27). If majority sampling is enabled, an additional sample oc-
curs. If the two samples differ, a third sample occurs to determine which of the first two samples
is correct. The SAMPTIME register (Figure 5-19 on page 5-38) controls the time between sam-
ples. Majority sampling causes a substantial increase in PTS cycle execution time (Table 5-4 on
page 5-12).
End-of-PTS
Conventional
Conventional
Interrupt
10 PTS Serviced Interrupts
Interrupt
Interrupts
LSB
Bit 0
1.5 Bit Times
MSB
Bit 7
RXD
(Port pin)
Parity
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Start
Stop
Optional
Parity Bit
A3118-01
Figure 5-27. Asynchronous SIO Receive Timing
The first PTS cycle must be started manually.
• Initialize the RXD port pin and the SCK signal to the system-required logic level before
starting a reception.
• Add the contents of the timer register to the Baud_value (Figure 5-19 on page 5-38) and
store the result into the EPA time register. This sets up the timing for the first interrupt and
causes the first interrupt to occur at the proper baud rate.
The following example uses EPA0 to capture the start bit and P2.0 to receive the data (RXD). It
sets up an asynchronous serial I/O PTS routine that receives 16 bytes each with eight data bits and
a parity bit. This example uses several user-defined registers. R_COUNT defines the number of
bytes to receive and RXDDONE is a flag that is set when all bytes are received.
1. Disable the interrupts and the PTS.
— Use the DI instruction to disable all standard interrupts and the DPTS instruction to
disable the PTS.
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2. Set-up the stack pointer.
3. Reset all interrupt mask registers.
— Clear INT_MASK, INT_MASK1and PI_MASK.
4. Initialize P2.0 to function as the RXD signal.
— Set P2_DIR.0 (selects input).
— Clear P2_MODE.0 (selects LSIO function).
— Set P2_REG.0 (initializes RXD input to “1”).
5. Initialize and enable the timer; select up counting, internal clock, and prescaler disabled.
— Set T1CONTROL bits 6 and 7 (Figure 11-8 on page 11-16).
6. Initialize the PTSCB as shown in Table 5-16.
Table 5-16. ASIO Receive Mode PTSCBs
PTSCB1
PTSCB2
PTSVEC (H) = pointer to PTSCB2
PTSVEC (L) = pointer to PTSCB2
BAUD (H) = 01H
Unused
SAMPTIME = 01H
DATA (H) = 00H (clear register to receive data)
DATA (L) = 00H (clear register to receive data)
PTSCON1 = 60H (enable odd parity)
PORTMASK = 01H (P2.0 = RXD)
PORTREG (H) = 1FH (P2_PIN)
BAUD (L) = ) A0H
EPAREG (H) = 1FH (EPA0_TIME)
EPAREG (L) = 42H (EPA0_TIME)
PTSCON = 21H (SSIO receive mode, majority
sampling)
PTSCOUNT = 0AH (receive 8 data bits, 1 parity bit)
PORTREG (L) = D6H (P2_PIn)
7. Enable EPA0 interrupt.
— Set INT_MASK.2.
8. Load the number of bytes to transmit into the user_defined transmit count register
(R_COUNT) and clear the user-defined reception-done flag (RXDDONE).
— LD R_COUNT, #16
— CLRB RXDDONE
9. Select PTS service for EPA0.
— Set PTSSEL.2.
10. Set-up EPA0 to capture on falling edges.
— Set EPA0_CON.4 (Figure 11-10 on page 11-19).
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STANDARD AND PTS INTERRUPTS
11. Enable the PTS and conventional interrupts.
— Use the EI instruction to enable all standard interrupts and the EPTS instruction to
enable the PTS.
12. Toggle the RXD input to start the reception. The EPA will generate a conventional
interrupt. This interrupt service routine should be the same as the end-of-PTS rountine.
The service routine can determine if this is a start reception interrupt or a end-of-PTS
interrupt by reading the EPA0_CON register. If the register is set to capture mode, then
this is the start reception interrupt.
The interrupt service routine contains the following steps.
1. Reconfigure the EPA channel to compare mode.
— Set EPA0_CON.6 (selects compare mode).
2. Initialize the first PTS cycle time by writing the time of the first interrupt to EPA0_TIME.
To set-up the correct value, multiply the baud_value (1A0H) by 1.5, add the product to the
current TIMER1 value, and store the result in EPA0_TIME. The baud_value determines
the time to the first PTS interrupt. When the interrupt occurs, the PTS transmits the first
data bit. The baud_value of 1A0H selects a baud rate of 9600. In this example, the value
added to the current TIMER1 value is 270H.
3. Select PTS service for EPA0.
— Set PTSSEL.2.
4. The PTS routine begins sampling the data every 1.5 bit times. When PTSCOUNT
decrements to zero, the PTS calls the end-of-PTS interrupt (Figure 5-28). The interrupt
service routine should check to see if a framing or parity error occurred (Figure 5-19 on
page 5-38), clear the DATA registers to prepare for the next reception, reload the
PTSCOUNT and PTSCON1 registers, and reconfigure the EPA channel to select capture
on falling edge mode. Note that PTS service is not enabled for the EPA channel at this time
because the next interrupt must be a conventional interrupt.
5. To determine when all bytes have been transmitted, create a loop routine to check the
status of the RXDDONE flag.
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End-Of-PTS Interrupt
Save Critical Data
Y
Start Bit?
N
Disable EPA Channel
Clear Interrupt Request Bit
Y
Y
Y
Start Bit Error?
N
Framing Error?
N
Initialize
EPA Channel
Parity Error?
N
Set Time To First
Bit Sample
Save Received Data
RXDDONE = 3
R_COUNT = R_COUNT - 1
Enable PTS Service
for EPA Channel
Y
R_COUNT = 0?
N
Set-up next data reception
- Clear DATA register
- Reload PTSCOUNT and PTSCON1 registers
- Select PTS service for EPA channel
- Re-initialize the EPA channel
RXDDONE = 1
Load Critical Data
Return
A3277-01
Figure 5-28. Asynchronous SIO Receive Mode — End-of-PTS Interrupt Routine Flowchart
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6
I/O Ports
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CHAPTER 6
I/O PORTS
I/O ports provide a mechanism to transfer information between the device and the surrounding
system circuitry. They can read system status, monitor system operation, output device status,
configure system options, generate control signals, provide serial communication, and so on.
Their usefulness in an application is limited only by the number of I/O pins available and the
imagination of the engineer.
6.1 I/O PORTS OVERVIEW
Standard I/O port registers are located in the SFR address space and they can be windowed. Mem-
ory-mapped I/O port registers are located in memory-mapped address space. Memory-mapped
registers must be accessed with indirect or indexed addressing; they cannot be windowed. All
ports can provide low-speed input/output pins or serve alternate functions. Table 6-1 provides an
overview of the device I/O ports. The remainder of this chapter describes the ports in more detail
and explains how to configure the pins. The chapters that cover the associated peripherals discuss
using the pins for their special functions.
Table 6-1. Device I/O Ports
Port
Port 0
Bits
Type
Direction
Associated Peripheral(s)
A/D converter (MC, MD)
A/D converter, EPA (MH)
8
Standard
Input-only
A/D converter, EPA (MC, MD)
5 (MC)
8 (MD)
Standard
Input-only
P1.7:6 are digital input-only
channels for the 8XC196MD.
Port 1
4 (MH)
8
Standard
Standard
Bidirectional SIO
EPA and timers (MC, MD)
Port 2
Bidirectional
EPA and timers, SIO (MH)
Port 3
Port 4
Port 5
Port 6
8
8
8
8
Memory-mapped
Memory-mapped
Memory-mapped
Standard
Bidirectional Address/data bus
Bidirectional Address/data bus
Bidirectional Bus control
Output-only PWM, waveform generator
EPA, frequency generator
Port 7 (MD)
8
Standard
Bidirectional
P7.6:4 are low-speed input/output pins
only; they have no peripheral functions.
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6.2 INPUT-ONLY PORTS 1 (MC, MD ONLY) AND 0
Port 0 is an eight-bit, high-impedance, input-only port that provides analog and digital inputs. The
input-only pins can be read as digital inputs; most of them are also inputs to the A/D converter.
The input-only ports differ from the other standard ports in that their pins can be used only as in-
puts to the digital or analog circuitry. On the 8XC196MC and 8XC196MD, port 1 is an input-only
port that serves the same purpose as port 0. The 8XC196MC implements five pins, while the
8XC196MD implements all eight.
8XC196MH: On the 8XC196MH, port 1 is a standard bidirectional port that shares pins with the
serial I/O port. (See “Bidirectional Ports 1 (MH Only), 2, 5, and 7 (MD Only)” on page 6-4.)
Because port 0 (and port 1 of the 8XC196MC, MD) is permanently configured as an input-only
port, it has no configuration registers. Its single register, Px_PIN, can be read to determine the
current state of the pin. The register is byte-addressable and can be windowed. (See “Windowing”
on page 5-16)
Table 6-2 lists the standard input-only port pins and Table 6-3 describes the Px_PIN status regis-
ter.
Table 6-2. Standard Input-only Port Pins
Special-function
Signal(s)
Special-function
Signal Type
Associated
Peripheral
Port Pin
P0.5:0
P0.6
ACH5:0
Input
A/D converter
ACH6
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
—
A/D converter
EPA
T1CLK (MH)
ACH7
A/D converter
EPA
P0.7
T1DIR (MH)
ACH8
P1.0 (MC, MD)
P1.1 (MC, MD)
A/D converter
A/D converter
A/D converter
EPA
ACH9
ACH10
T1CLK
ACH11
T1DIR
ACH12
ACH13
—
P1.2 (MC, MD)
P1.3 (MC, MD)
A/D converter
EPA
P1.4 (MC, MD)
P1.5 (MD)
A/D converter
A/D converter
—
P1.6 (MD)
P1.7 (MD)
—
—
—
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I/O PORTS
Table 6-3. Input-only Port Registers
Address Description
1FA8H (MC, MD) Each bit of P0_PIN reflects the current state of the corresponding
Mnemonic
P0_PIN
1FDAH (MH) port 0 pin.
P1_PIN (MC, MD) 1FA9H (MC, MD) Each bit of P1_PIN reflects the current state of the corresponding
port 1 pin.
6.2.1 Standard Input-only Port Operation
Figure 6-1 is a schematic of an input-only port pin. Transistors Q1 and Q2 serve as electrostatic
discharge (ESD) protection devices; they are referenced to VREF and ANGND. Transistor Q3 is
an additional ESD protection device; it is referenced to VSS (digital ground). Resistor R1 limits
current flow through Q3 to acceptable levels. At this point, the input signal is sent to the analog
multiplexer and to the digital level-translation buffer. The level-translation buffer converts the in-
put signals to work with the VCC and VSS digital voltage levels used by the CPU core. This buffer
is Schmitt-triggered for improved noise immunity. The signals are latched in the P0_PIN or
P1_PIN register and are output onto the internal bus when P0_PIN or P1_PIN is read.
Internal Bus
Vcc
VREF
VREF
To Analog MUX
PORT 0
Data Register
Level
Translation
Buffer
Q1
Buffer
P0_PIN
Input Pin
150 to 200 Ohms
Q
D
R1
LE
Q3
Q2
Read Port
PH1 Clock
Vss
Vss
Vss
ANGND ANGND
A0236-01
Figure 6-1. Standard Input-only Port Structure
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6.2.2 Standard Input-only Port Considerations
Port 0 and 1 pins are unique in that they may individually be used as digital inputs and analog
inputs at the same time. However, reading the port induces noise into the A/D converter, decreas-
ing the accuracy of any conversion in progress. We strongly recommend that you not read the
port while an A/D conversion is in progress. To reduce noise, the P0_PIN or P1_PIN register is
clocked only when the port is read.
These port pins are powered by the analog reference voltage (VREF) and analog ground (ANGND)
pins. If the port pins are to function as either analog or digital inputs, the VREF and ANGND pins
must provide power. If the voltage applied to the analog input exceeds VREF or ANGND by more
than 0.5 volts, current will be driven through Q1 or Q2 into the reference circuitry, decreasing the
accuracy of all analog conversions.
The port pin is sampled one state time before the read buffer is enabled. Sampling occurs during
phase 1 (while CLKOUT is low) and resolves the value of the pin before it is presented to the
internal bus. To ensure that the value is recognized, it must be valid 45 ns before the rising edge
of CLKOUT and must remain valid until CLKOUT falls. If the pin value changes during the sam-
ple time, the new value may or may not be recorded.
As a digital input, a pin acts as a high-impedance input. However, as an analog input, a pin must
provide current for a short time to charge the internal sample capacitor when a conversion begins.
This means that if a conversion is taking place on a port pin, its input characteristics change mo-
mentarily.
6.3 BIDIRECTIONAL PORTS 1 (MH ONLY), 2, 5, AND 7 (MD ONLY)
Although the bidirectional ports are very similar in both circuitry and configuration, port 5 differs
from the others in some ways. Port 5, a memory-mapped port, uses a standard CMOS input buffer
because of the high speeds required for system control functions. The remaining bidirectional
ports use Schmitt-triggered input buffers for improved noise immunity.
NOTE
Ports 3 and 4 are significantly different from the other bidirectional ports. See
“Bidirectional Ports 3 and 4 (Address/Data Bus)” on page 6-14 for details on
the structure and operation of these ports.
Table 6-4 lists the bidirectional port pins with their special-function signals and associated periph-
erals.
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I/O PORTS
Table 6-4. Bidirectional Port Pins
Special-function Special-function
Associated
Peripheral
Port Pin
Signal(s)
Signal Type
P1.0 (MH) TXD0
P1.1 (MH) RXD0
P1.2 (MH) TXD1
P1.3 (MH) RXD1
O
SIO
SIO
SIO
SIO
EPA
EPA
I/O
O
I/O
I/O
I/O
P2.0
EPA0
EPA1 (MC, MD)
P2.1
SCLK0# (MH)
BCLK0 (MH)
I/O
I
SIO
SIO
EPA2 (MC, MD)
EPA1 (MH)
I/O
I/O
I/O
O
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
P2.2
P2.3
EPA3 (MC, MD)
COMP3 (MH)
COMP0
P2.4
P2.5
P2.6
O
COMP1
O
COMP2
O
COMP3 (MC, MD)
O
P2.7
SCLK1# (MH)
BCLK1 (MH)
I/O
I
SIO
SIO
P5.0
P5.1
P5.2
P5.3
P5.4
P5.5
P5.6
P5.7
ALE/ADV#
INST
O
O
Bus controller
Bus controller
Bus controller
Bus controller
Bus controller
Bus controller
Bus controller
Bus controller
EPA
WR#/WRL#
RD#
O
O
ONCE
I
BHE#/WRH#
READY
O
I
BUSWIDTH
I
P7.0 (MD) EPA4
P7.1 (MD) EPA5
P7.2 (MD) COMP4
P7.3 (MD) COMP5
I/O
I/O
O
EPA
EPA
O
EPA
P7.4 (MD)
P7.5 (MD)
P7.6 (MD)
—
—
—
I/O
I/O
I/O
O
—
—
—
P7.7 (MD) FREQOUT
Frequency generator
6-5
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Table 6-5 lists the registers associated with the bidirectional ports. Each port has three control reg-
isters (Px_MODE, Px_DIR, and Px_REG); they can be both read and written. The Px_PIN regis-
ter is a status register that returns the logic level present on the pins; it can only be read. The
registers for the standard ports are byte-addressable and can be windowed. The port 5 registers
must be accessed using 16-bit addressing and cannot be windowed. “Bidirectional Port Consid-
erations” on page 6-12 discusses special considerations for reading P2_REG.7 and P6_REG.7:4.
Table 6-5. Bidirectional Port Control and Status Registers
Mnemonic
Address
Description
P1_DIR (MH)
P2_DIR
P5_DIR
1F9BH
Port x Direction
1FD2H
1FF3H
1FD3H
Each bit of Px_DIR controls the direction of the corresponding pin.
0 = complementary output (output only)
1 = input or open-drain output (input, output, or bidirectional) Open-
drain outputs require external pull-ups.
P7_DIR (MD)
P1_MODE (MH)
P2_MODE
P5_MODE
1F99H
1FD0H
1FF1H
1FD1H
Port x Mode
Each bit of Px_MODE controls whether the corresponding pin
functions as a standard I/O port pin or as a special-function signal.
P7_MODE (MD)
0 = standard I/O port pin
1 = special-function signal
P1_PIN (MH)
P2_PIN
P5_PIN
1F9FH
1FD6H
1FF7H
1FD7H
Port x Input
Each bit of Px_PIN reflects the current state of the corresponding
pin, regardless of the pin configuration.
P7_PIN (MD)
P1_REG (MH)
P2_REG
P5_REG
1F9DH
1FD4H
1FF5H
1FD5H
Port x Data Output
For an input, set the corresponding Px_REG bit.
For an output, write the data to be driven out by each pin to the
corresponding bit of Px_REG. When a pin is configured as standard
I/O (Px_MODE.y = 0), the result of a CPU write to Px_REG is
immediately visible on the pin. When a pin is configured as a
special-function signal (Px_MODE.y = 1), the associated on-chip
peripheral or off-chip component controls the pin. The CPU can still
write to Px_REG, but the pin is unaffected until it is switched back to
its standard I/O function.
P7_REG (MD)
This feature allows software to configure a pin as standard I/O (clear
Px_MODE.y), initialize or overwrite the pin value, then configure the
pin as a special-function signal (set Px_MODE.y). In this way, initial-
ization, fault recovery, exception handling, etc., can be done without
changing the operation of the associated peripheral.
6.3.1 Bidirectional Port Operation
Figure 6-2 shows the logic for driving the output transistors, Q1 and Q2. Q1 can source at least
–3 mA at VCC – 0.7 volts. Q2 can sink at least 3 mA at 0.45 volts. (Consult the datasheet for spec-
ifications.)
6-6
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I/O PORTS
In I/O mode (selected by clearing Px_MODE.y), Px_REG and Px_DIR are input to the multiplex-
ers. These signals combine to drive the gates of Q1 and Q2 so that the output is high, low, or high
impedance. Table 6-6 is a logic table for I/O operation of these ports.
In special-function mode (selected by setting Px_MODE.y), SFDIR and SFDATA are input to the
multiplexers. These signals combine to drive the gates of Q1 and Q2 so that the output is high,
low, or high impedance. Special-function output signals clear SFDIR; special-function input sig-
nals set SFDIR. Table 6-7 is a logic table for special-function operation of these ports. Even if a
pin is to be used in special-function mode, you must still initialize the pin as an input or output
by writing to Px_DIR.
Resistor R1 provides ESD protection for the pin. Input signals are buffered. The standard ports
use Schmitt-triggered buffers for improved noise immunity. Port 5 uses a standard input buffer
because of the high speeds required for bus control functions. The signals are latched into the
Px_PIN sample latch and output onto the internal bus when the Px_PIN register is read.
The falling edge of RESET# turns on transistor Q3, which remains on for about 300 ns, causing
the pin to change rapidly to its reset state. The active-low level of RESET# turns on transistor Q4,
which weakly holds the pin high. (Q4 can source approximately –10 µA; consult the datasheet
for exact specifications.) Q4 remains on, weakly holding the pin high, until your software writes
to the Px_MODE register.
NOTE (8XC196MC, MD Only)
P2.7 is an exception. After reset, P2.7 carries the CLKOUT signal (half the
crystal input frequency) rather than being held high. When CLKOUT is
selected, it is always a complementary output.
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Internal Bus
Vcc
Px_REG
0
SFDATA
1
Q1
I/O Pin
Px_DIR
0
Q2
SFDIR
1
Vss
Px_MODE
Sample
Latch
150Ω to 200Ω
R1
Px_PIN
Q
D
LE
Read Port
PH1 Clock
Vcc
Medium
Pullup
300ns Delay
Q3
RESET#
Vcc
Weak
RESET#
R
S
Pullup
Q
Q4
Any Write to Px_MODE
A0238-04
Figure 6-2. Bidirectional Port Structure
6-8
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I/O PORTS
Table 6-6. Logic Table for Bidirectional Ports in I/O Mode
Open-drain
Complementary Output
Output
Configuration
Input
Px_MODE
Px_DIR
SFDIR
SFDATA
Px_REG
Q1
0
0
0
0
0
0
1
1
X
X
X
X
X
X
X
X
0
1
0, 1 (Note 2)
off
1
off
on
0
on
off
1
off
off
Q2
on, off (Note 2)
X (Note 3)
Px_PIN
high impedance (Note 4)
NOTES:
1. X = Don’t care.
2. If Px_REG is cleared, Q2 is on; if Px_REG is set, Q2 is off.
3. Px_PIN contains the current value on the pin.
4. During reset and until the first write to Px_MODE, Q4 is on.
Table 6-7. Logic Table for Bidirectional Ports in Special-function Mode
Open-drain
Configuration
Complementary Output
Input
Output
Px_MODE
Px_DIR
SFDIR
SFDATA
Px_REG
Q1
1
0
1
0
1
1
1
1
0
0
1
0, 1 (Note 2)
X
1
0
1
1
X
X
1
off
on
0
on
off
1
off
off
Q2
on, off (Note 2)
X (Note 3)
off
Px_PIN
high impedance (Note 4)
NOTES:
1. X = Don’t care.
2. If Px_REG is cleared, Q2 is on; if Px_REG is set, Q2 is off.
3. Px_PIN contains the current value on the pin.
4. During reset and until the first write to Px_MODE, Q4 is on.
6.3.2 Bidirectional Port Pin Configurations
Each bidirectional port pin can be individually configured to operate either as an I/O pin or as a
pin for a special-function signal. In the special-function configuration, the signal is controlled by
an on-chip peripheral or an off-chip component. In either configuration, two modes are possible:
• complementary output (output only)
• high-impedance input or open-drain output (input, output, or bidirectional)
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To prevent the CMOS inputs from floating, the bidirectional port pins are weakly pulled high dur-
ing and after reset, until your software writes to Px_MODE. The default values of the control reg-
isters after reset configure the pins as high-impedance inputs with weak pull-ups. To ensure that
the ports are initialized correctly and that the weak pull-ups are turned off, follow this suggested
initialization sequence:
1. Write to Px_DIR to establish the individual pins as either inputs or outputs. (Outputs will
drive the data that you specify in step 3.)
— For a complementary output, clear its Px_DIR bit.
— For a high-impedance input or an open-drain output, set its Px_DIR bit. (Open-drain
outputs require external pull-ups.)
2. Write to Px_MODE to select either I/O or special-function mode. Writing to Px_MODE
(regardless of the value written) turns off the weak pull-ups. Even if the entire port is to be
used as I/O (its default configuration after reset), you must write to Px_MODE to ensure
that the weak pull-ups are turned off.
— For a standard I/O pin, clear its Px_MODE bit. In this mode, the pin is driven as
defined in steps 1 and 3.
— For a special-function signal, set its Px_MODE bit. In this mode, the associated
peripheral controls the pin.
3. Write to Px_REG.
— For output pins defined in step 1, write the data that is to be driven by the pins to the
corresponding Px_REG bits. For special-function outputs, the value is immaterial
because the peripheral controls the pin. However, you must still write to Px_REG to
initialize the pin.
— For input pins defined in step 1, set the corresponding Px_REG bits.
Table 6-8 lists the control register values for each possible configuration. For special-function
outputs, the Px_REG value is irrelevant (don’t care) because the associated peripheral controls
the pin in special-function mode. However, you must still write to Px_REG to initialize the pin.
For a bidirectional pin to function as an input (either special function or port pin), you must set
Px_REG.
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I/O PORTS
Table 6-8. Control Register Values for Each Configuration
Desired Pin Configuration
Standard I/O Signal
Configuration Register Settings
Px_DIR Px_MODE†
Px_REG
Complementary output, driving 0
0
0
1
1
1
0
0
0
0
0
0
1
0
1
1
Complementary output, driving 1
Open-drain output, strongly driving 0
Open-drain output, high impedance
Input
Special-function signal
Px_DIR Px_MODE†
Px_REG
Complementary output, output value controlled by peripheral
Open-drain output, output value controlled by peripheral
0
1
1
1
1
1
X
X
1
Input
†
During reset and until the first write to Px_MODE, the pins are weakly held high.
6.3.3 Bidirectional Port Pin Configuration Example
Assume that you wish to configure the pins of a bidirectional port as shown in Table 6-9.
Table 6-9. Port Configuration Example
Port Pin(s)
Px.0, Px.1
Configuration
high-impedance input
Data
high impedance
0
Px.2, Px.3
Px.4
open-drain output
open-drain output
1 (assuming external pull-up)
Px.5, Px.6
Px.7
complementary output
complementary output
0
1
To do so, you could use the following example code segment. Table 6-10 shows the state of each
pin after reset and after execution of each line of the example code.
LDB Px_DIR,#00011111B
LDB Px_MODE,#00000000B
LDB Px_REG,#10010011B
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Table 6-10. Port Pin States After Reset and After Example Code Execution
Resulting Pin States†
Action or Code
Px.7
Px.6
Px.5
Px.4
Px.3
Px.2
Px.1
Px.0
Reset
wk1
1
wk1
1
wk1
1
wk1
wk1
HZ1
HZ1
wk1
wk1
HZ1
0
wk1
wk1
HZ1
0
wk1
wk1
HZ1
HZ1
wk1
wk1
HZ1
HZ1
LDB Px_DIR, #00011111B
LDB Px_MODE, #00000000B
1
1
1
LDB Px_REG, #10010011B
1
0
0
†
wk1 = weakly pulled high, HZ1 = high impedance (actually a “1” with an external pull-up).
6.3.4 Bidirectional Port Considerations
This section outlines special considerations for using the pins of these ports.
Port 1 (8XC196MH)
After reset, your software must configure the device to match the
external system. This is accomplished by writing appropriate config-
uration data into P1_MODE. Writing to P1_MODE not only
configures the pins but also turns off the transistor that weakly holds
the pins high (Q4 in Figure 6-2 on page 6-8). For this reason, even if
port 1 is to be used as it is configured at reset, you should still write
data into P1_MODE.
Port 2
After reset, your software must configure the device to match the
external system. This is accomplished by writing appropriate config-
uration data into P2_MODE. Writing to P2_MODE not only
configures the pins but also turns off the transistor that weakly holds
the pins high (Q4 in Figure 6-2 on page 6-8). For this reason, even if
port 2 is to be used as it is configured at reset, you should still write
data into P2_MODE.
P2.7
A value written to P2_REG.7 is held in a buffer until P2_MODE.7 is
cleared, at which time the value is loaded into P2_REG.7. A value
read from P2_REG.7 is the value currently in the register, not the
value in the buffer. Therefore, any change to P2_REG.7 can be read
only after P2_MODE.7 is cleared.
Port 5
After reset, the device configures port 5 to match the external system.
The following paragraphs describe the states of the port 5 pins after
reset and until your software writes to the P5_MODE register.
Writing to P5_MODE not only configures the pins but also turns off
the transistor that weakly holds the pins high (Q4 in Figure 6-2 on
page 6-8). For this reason, even if port 5 is to be used as it is
configured at reset, you should still write data into P5_MODE.
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I/O PORTS
P5.0/ALE
If EA# is high on reset (internal access), the pin is weakly held high
until your software writes to P5_MODE. If EA# is low on reset
(external access), either ALE or ADV# is activated as a system
control pin, depending on the ALE bit of CCR0. In either case, the
pin becomes a true complementary output.
P5.1/INST
This pin remains weakly held high until your software writes config-
uration data into P5_MODE.
P5.2/WR#/WRL#
P5.3/RD#
This pin remains weakly held high until your software writes config-
uration data into P5_MODE.
If EA# is high on reset (internal access), the pin is weakly held high
until your software writes to P5_MODE. If EA# is low on reset
(external access), RD# is activated as a system control pin and the
pin becomes a true complementary output.
P5.4
This pin is weakly held high until your software writes to
P5_MODE. P5.4 is the enable pin for ONCE mode (see Chapter 14,
“Special Operating Modes”) and one of the enable pins for Intel-
reserved test modes. Because a low input during reset could cause the
device to enter ONCE mode or a reserved test mode, exercise
caution if you use this pin for input. Be certain that your system
meets the VIH specification (listed in the datasheet) during reset to
prevent inadvertent entry into ONCE mode or a test mode.
P5.5/BHE#/WRH#
P5.6/READY
This pin is weakly held high until the CCB fetch is completed. At
that time, the state of this pin depends on the value of the BW0 bit of
the CCRs. If BW0 is clear, the pin remains weakly held high until
your software writes to P5_MODE. If BW0 is set, BHE# is activated
as a system control pin and the pin becomes a true complementary
output.
This pin remains weakly held high until the CCB fetch is completed.
At that time, the state of this pin depends on the value of the IRC0–
IRC2 bits of the CCRs. If IRC0–IRC2 are all set (111B), READY is
activated as a system control pin. This prevents the insertion of
infinite wait states upon the first access to external memory. For any
other values of IRC0–IRC2, the pin is configured as I/O upon reset.
NOTE: If IRC0–IRC2 of the CCB are all set (activating READY as
a system control pin) and P5_MODE.6 is cleared (config-
uring the pin as I/O), an external memory access may cause
the processor to lock up.
P5.7/BUSWIDTH
This pin remains weakly held high until your software writes config-
uration data into P5_MODE.
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6.4 BIDIRECTIONAL PORTS 3 AND 4 (ADDRESS/DATA BUS)
Ports 3 and 4 are eight-bit, bidirectional, memory-mapped I/O ports. They can be addressed only
with indirect or indexed addressing and cannot be windowed. Ports 3 and 4 provide the multi-
plexed address/data bus. In programming modes, ports 3 and 4 serve as the programming bus
(PBUS). Port 5 supplies the bus-control signals.
During external memory bus cycles, the processor takes control of ports 3 and 4 and automatical-
ly configures them as complementary output ports for driving address/data or as inputs for read-
ing data. For this reason, these ports have no mode registers.
Systems with EA# tied inactive have idle time between external bus cycles. When the address/da-
ta bus is idle, you can use the ports for I/O. Like port 5, these ports use standard CMOS input
buffers. However, ports 3 and 4 must be configured entirely as complementary or open-drain
ports; their pins cannot be configured individually. Systems with EA# tied active cannot use ports
3 and 4 as standard I/O; when EA# is active, these ports will function only as the address/data bus.
Table 6-11 lists the port 3 and 4 pins with their special-function signals and associated peripher-
als. Table 6-12 lists the registers that affect the function and indicate the status of ports 3 and 4.
Table 6-11. Ports 3 and 4 Pins
Special-function
Signal(s)
Special-function
Signal Type
Port Pins
Associated Peripheral
AD7:0
I/O
I/O
I/O
I/O
Address/data bus, low byte
Programming bus, low byte
Address/data bus, high byte
Programming bus, high byte
P3.7:0
PBUS7:0
AD15:8
P4.7:0
PBUS15:8
Table 6-12. Ports 3 and 4 Control and Status Registers
Address Description
1FFEH
Mnemonic
P3_PIN
P4_PIN
Port x Input
1FFFH
Each bit of Px_PIN reflects the current state of the corresponding pin,
regardless of the pin configuration.
P3_REG
P4_REG
1FFCH
1FFDH
Port x Data Output
Each bit of Px_REG contains data to be driven out by the corresponding
pin.
When the device requires access to external memory, it takes control of
the port and drives the address/data bit onto the pin. The address/data
bit replaces your output during this time. When the external access is
completed, the device restores your data onto the pin.
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I/O PORTS
6.4.1 Bidirectional Ports 3 and 4 (Address/Data Bus) Operation
Figure 6-3 shows the ports 3 and 4 logic. During reset, the active-low level of RESET# turns off
Q1 and Q2 and turns on transistor Q3, which weakly pulls the pin high. (Q1 can source at least –
3 mA at VCC –0.7 volts; Q2 can sink at least 3 mA at 0.45 volts; and Q3 can source approximately
–10 µΑ at VCC –1.0 volts. Consult the datasheet for exact specifications.) During normal opera-
tion, an internal control signal, BUS CONTROL SELECT, controls the port.
When the microcontroller needs to access external memory, it clears BUS CONTROL SELECT,
which selects address/data as the input to the multiplexer. Address/data then drives Q1 and Q2 as
complementary outputs.
When external memory access is not required, the microcontroller sets BUS CONTROL SE-
LECT, which selects Px_REG as the input to the multiplexer. Px_REG then drives Q1 and Q2 as
open-drain outputs. (Open-drain outputs require external pull-up resistors.) In this configuration,
a port pin can be used as an input. The signal on the pin is latched in the Px_PIN register. The pins
can be read, making it easy to see which pins are driven low by the microcontroller and which are
driven high by external drivers. Table 6-13 is a logic table for ports 3 and 4 as I/O.
Internal Bus
VCC
VCC
Px_REG
1
0
Address/Data
Q1
Q3
I/O Pin
Q2
BUS CONTROL SELECT
0 = Address/Data
1 = I/O
RESET#
Px_PIN
A3116-01
Figure 6-3. Address/Data Bus (Ports 3 and 4) Structure
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Table 6-13. Logic Table for Ports 3 and 4 as Open-drain I/O
Configuration
Px_REG
Q1
Open-drain
0
off
on
0
1
off
off
Q2
Px_PIN
high impedance
6.4.2 Using Ports 3 and 4 as I/O
To use a port pin as an output, write the output data to the corresponding Px_REG bit. When the
device requires access to external memory, it takes control of the port and drives the address/data
bit onto the pin. The address/data bit replaces your output during this time. When the external ac-
cess is completed, the device restores your data onto the pin.
To use a port pin as an input, set the corresponding Px_REG bit to drive the pin to a high-imped-
ance state. You may then read the pin’s input value in the Px_PIN register. When the device re-
quires access to external memory, it takes control of the port. You must configure the input source
to avoid contention on the bus.
6.4.3 Design Considerations for Ports 3 and 4
When EA# is active, ports 3 and 4 will function only as the address/data bus. In these circum-
stances, an instruction that operates on P3_REG or P4_REG causes a bus cycle that reads from
or writes to the external memory location corresponding to the SFR’s address. (For example, writ-
ing to P4_REG causes a bus cycle that writes to external memory location 1FFDH.) Because
P3_REG and P4_REG have no effect when EA# is active, the bus will float during long periods
of inactivity (such as during a BMOV or TIJMP instruction).
When EA# is inactive, ports 3 and 4 output the contents of the P3_REG and P4_REG registers,
which reset to FFH, placing the pins in a high-impedance state. Ports 3 and 4 will float unless you
either connect external resistors to the pins or write zeros to the P3_REG and P4_REG registers.
6.5
STANDARD OUTPUT-ONLY PORT 6
Port 6 is an output-only port that provides output pins for the waveform generator and pulse-width
modulator (PWM). The port 6 pins can be configured to operate either as port pins or as output
pins for the waveform generator or pulse-width modulator. Table 6-2 lists the pins with their spe-
cial-function signals and associated peripherals.
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I/O PORTS
Table 6-14. Standard Output-only Port Pins
Special-function
Signal(s)
Special-function
Signal Type
Associated
Peripheral
Port Pin
P6.0
P6.1
P6.2
P6.3
P6.4
P6.5
P6.6
P6.7
WG1#
Output
Waveform generator
Waveform generator
Waveform generator
Waveform generator
Waveform generator
Waveform generator
PWM
WG1
Output
Output
Output
Output
Output
Output
Output
WG2#
WG2
WG3#
WG3
PWM0
PWM1
PWM
Table 6-15. Output-only Port Control Register
Address Description
Mnemonic
WG_OUTPUT 1FC0H
Port 6 Output Control Register
This register controls the port 6 pins in I/O mode. Its functions differ when the
port 6 pins are being used as waveform generator or PWM outputs.
6.5.1 Output-only Port Operation
Figure 6-4 shows a simplified circuit schematic for port 6. Port 6 has a single configuration and
control register, WG_OUTPUT. Transistor Q1 can source at least –200 µA at VCC–0.3 volts. For
pins P6.0–P6.5, transistor Q2 can sink at least 10 mA at 0.45 volts. For pins P6.6 and P6.7, Q2
can sink at least 200 µA at 0.3 volts.
6.5.2 Configuring Output-only Port Pins
Port 6 has a single configuration register, WG_OUTPUT (Figure 6-5). This register controls the
pin functions, values, and output polarity. This register can be addressed either as a word or as
separate bytes, and it can be windowed. The functions of this register are different for configuring
general-purpose outputs than for configuring waveform generator and PWM outputs.
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Internal Bus
Vcc
WG_OUTPUT
Q1
Output Pin
Combinational Logic
Q2
A2764-01
Figure 6-4. Output-only Port
Address:
Reset State:
1FC0H
0000H
WG_OUTPUT (Port 6)
The port 6 output configuration (WG_OUTPUT) register controls port 6 functions. If you are using port
6 for general-purpose outputs, write C0H (for active-high outputs) or 00H (for active-low outputs) to
the high byte of WG_OUTPUT, and write the desired pin values to the low byte. If you are using port 6
for waveform generator or PWM outputs, please refer to Chapter 9, “Waveform Generator” or Chapter
10, “Pulse-width Modulator” for a description of the WG_OUTPUT register functions.
15
8
OP1
D7
OP0
D6
—
M7
D4
M6
D3
M5:4
D2
M3:2
D1
M1:0
D0
7
0
D5
Bit
Number
Bit
Mnemonic
Function
15:14
OP1:0
Output Polarity
These bits select the output polarity of the port 6 pins.
0 = active-low outputs
1 = active-high outputs
13
—
Reserved; for compatibility with future devices, write zero to this bit.
Mode
12:8
M7:0
These bits select either the peripheral function or general-purpose
output function of the port 6 pins. Clear these bits for general-purpose
output.
Figure 6-5. Port 6 Output Configuration (WG_OUTPUT) Register
6-18
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I/O PORTS
Address:
Reset State:
1FC0H
0000H
WG_OUTPUT (Port 6) (Continued)
The port 6 output configuration (WG_OUTPUT) register controls port 6 functions. If you are using port
6 for general-purpose outputs, write C0H (for active-high outputs) or 00H (for active-low outputs) to
the high byte of WG_OUTPUT, and write the desired pin values to the low byte. If you are using port 6
for waveform generator or PWM outputs, please refer to Chapter 9, “Waveform Generator” or Chapter
10, “Pulse-width Modulator” for a description of the WG_OUTPUT register functions.
15
8
OP1
D7
OP0
D6
—
M7
D4
M6
D3
M5:4
D2
M3:2
D1
M1:0
D0
7
0
D5
Bit
Number
Bit
Mnemonic
Function
7:0
D7:0
Data
In general-purpose output mode, these bits hold the values to be driven
out on the pins. Write the desired values to these bits (bits 7:0
correspond to pins P6.7:0).
Figure 6-5. Port 6 Output Configuration (WG_OUTPUT) Register (Continued)
6-19
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7
Serial I/O (SIO) Port
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CHAPTER 7
SERIAL I/O (SIO) PORT
A serial input/output (SIO) port provides a means for the system to communicate with external
devices. The 8XC196MH device has a two-channel serial I/O port that shares pins with ports 1
and 2. (The 8XC196MC and 8XC196MD devices do not have serial I/O ports.) This chapter de-
scribes the SIO port and explains how to configure it. Chapter 6, “I/O Ports,” explains how to con-
figure the port pins for their special functions. Refer to Appendix B for details about the signals
discussed in this chapter.
7.1 SERIAL I/O (SIO) PORT FUNCTIONAL OVERVIEW
The serial I/O port (Figure 7-1) is an asynchronous/synchronous port that includes a universal
asynchronous receiver and transmitter (UART). The UART has two synchronous modes (modes
0 and 4) and three asynchronous modes (modes 1, 2, and 3) for both transmission and reception.
Internal
Data
Bus
RXDx
TXDx
SBUFx_RX
Receive Shift Register
Transmit Shift Register
SBUFx_TX
BCLKx
0
TI
Baud Rate
Generator
Control Logic
Interrupts
RI
XTAL1
1
SPx_STATUS
SPx_CON
SPx_BAUD
MSB
A2774-01
Figure 7-1. SIO Block Diagram
The serial port receives data into the receive buffer (SBUFx_RX) and transmits data from the port
through the transmit buffer (SBUFx_RX). The transmit and receive buffers are separate registers,
permitting simultaneous reads and writes to both. These buffers support continuous transmissions
and allow reception of a second byte before the first byte has been read.
7-1
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An independent, 15-bit baud-rate generator controls the baud rate of the serial port. Either XTAL1
or BCLKx can provide the clock signal for modes 0–3. In mode 4, the internal shift clock is output
on SCLKx# or an external shift clock is input on SCLKx# (in which case the baud-rate generator
is not used). The baud-rate register (SPx_BAUD) selects the clock source and the baud rate. The
serial port control register (SPx_CON) register controls whether SCLKx# outputs the internal
shift clock or inputs an external shift clock.
7.2 SERIAL I/O PORT SIGNALS AND REGISTERS
Table 7-1 describes the SIO signals and Table 7-2 describes the control and status registers.
Table 7-1. Serial Port Signals
Serial
Port
Pin
Serial Port
Signal
Port
Signal
Type
Description
P1.0 TXD0
P1.2 TXD1
O
Transmit Serial Data.
In modes 1, 2, 3, and 4, TXDx transmits serial port output data. In
mode 0, it is the serial clock output.
P1.1 RXD0
P1.3 RXD1
I/O
I/O
Receive Serial Data.
In modes 1, 2, 3, and 4, RXDx receives serial port input data. In mode
0, it functions as an input or an open-drain output for data.
P2.1 SCLK0#/BCLK0
P2.7 SCLK1#/BCLK1
Baud Clock.
BCLKx can provide an external clock source for the baud-rate
generator input.
Shift Clock. In mode 4 only, SCLKx# are bidirectional shift clock
signals that synchronize the serial data transfer. The DIR bit in the
SP_CON register controls the direction of SCLKx#:
DIR = 0 causes SCLKx# to output the internal shift clock.
DIR = 1 allows an external shift clock to be input on SCLKx#.
Table 7-2. Serial Port Control and Status Registers
Address Description
0013H
Mnemonic
INT_MASK1
Interrupt Mask 1
Setting the TIx bit enables the transmit interrupt; clearing the bit
disables (masks) the interrupt.
Setting the RIx bit enables the receive interrupt; clearing the bit
disables (masks) the interrupt.
Setting the SPE bit enables the serial port receive error interrupt.
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SERIAL I/O (SIO) PORT
Table 7-2. Serial Port Control and Status Registers (Continued)
Address Description
0012H
Mnemonic
INT_PEND1
Interrupt Pending 1
When set, the TIx bit indicates a pending transmit interrupt.
When set, the RIx bit indicates a pending receive interrupt.
When set, the SPE bit indicates a pending serial port receive error
interrupt. You must read the PI_PEND register to determine which
channel generated the interrupt.
P1_DIR
1F9BH
1F99H
Port 1 Direction
This register selects the direction of each port 1pin. Set P1_DIR.1
and P1_DIR.3 to configure RXD0 (P1.1) and RXD1 (P1.3) as high-
impedance inputs/open-drain outputs, and clear P1_DIR.0 and
P1_DIR.2 to configure TXD0 (P1.0) and TXD1 (P1.2) as comple-
mentary outputs.
P1_MODE
Port 1 Mode
This register selects either the general-purpose input/output function
or the peripheral function for each pin of port 1. Set P1_MODE.3:0
to configure TXD0 (P1.0), TXD1 (P1.2), RXD0 (P1.1), and RXD1
(P1.3) for the SIO port.
P1_PIN
P1_REG
P2_DIR
1F9FH
1F9DH
1FD2H
Port 1 Pin State
Four bits of this register contain the values of the TXD0 (P1.0),
RXD0 (P1.1), TXD1 (P1.2), and RXD1 (P1.3) pins. Read P1_PIN to
determine the current value of the TXDx and RXDx pins.
Port 1 Output Data
This register holds data to be driven out on the pins of port 1. Set
P1_REG.1 and P1_REG.3 for the RXDx pins. Set P1_REG.0 and
P1_REG.2 for the TXDx pins.
Port 2 Direction
This register selects the direction of each port 2 pin. To use BCLKx
as the baud-rate generator clock source for modes 0–3, or to use
mode 4 (in which case SCLKx# is the shift clock), set P2_DIR.1 and
P2_DIR.7 to configure SCLK0#/BCLK0 (P2.1) and SCLK1#/BCLK1
(P2.7) as high-impedance inputs/open-drain outputs.
P2_MODE
1FD0H
Port 2 Mode
This register selects either the general-purpose input/output function
or the peripheral function for each pin of port 2. Set P2_MODE.1
and P2_MODE.7 to configure SCLK0#/BCLK0 (P2.1) and
SCLK1#/BCLK1 (P2.7) for the SIO port.
P2_PIN
1FD6H
1FD4H
Port 2 Pin State
Two bits of this register contain the values of the SCLK0#/BCLK0
(P2.1) and SCLK1#/BCLK1 (P2.7) pins. Read P2_PIN to determine
the current value of the pins.
P2_REG
Port 2 Output Data
This register holds data to be driven out on the pins of port 2. Set
P2_REG.1 and P2_REG.7 for the SCLK0#/BCLK0 (P2.1) and
SCLK1#/BCLK1 (P2.7) pins.
7-3
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Table 7-2. Serial Port Control and Status Registers (Continued)
Address Description
1FBCH
Mnemonic
PI_MASK
Peripheral Interrupt Mask
This register enables and disables multiplexed peripheral interrupts.
Setting an SPx bit enables a serial port receive error interrupt;
clearing the bit disables (masks) the interrupt.
PI_PEND
1FBEH
Peripheral Interrupt Pending
This register indicates pending multiplexed peripheral interrupts.
When set, an SPx bit indicates a pending serial port receive error
interrupt.
SBUF0_RX
SBUF1_RX
1F80H
1F88H
Serial Port x Receive Buffer
This register contains data received from the serial port.
SBUF0_TX
SBUF1_TX
1F82H
1F8AH
Serial Port x Transmit Buffer
This register contains data that is ready for transmission. In modes
1, 2, and 3, writing to SBUFx_TX starts a transmission. In mode 0,
writing to SBUFx_TX starts a transmission only if the receiver is
disabled (SPx_CON.3 = 0).
SP0_BAUD
SP1_BAUD
1F84H,1F85H
1F8CH,1F8DH
Serial Port x Baud Rate
This register selects the serial port baud rate and clock source. The
most-significant bit selects the clock source. The lower 15 bits
represent the BAUD_VALUE, an unsigned integer that determines
the baud rate.
SP0_CON
SP1_CON
1F83H
1F8BH
Serial Port x Control
This register selects the communications mode and enables or
disables the receiver, parity checking, and ninth-bit data transmis-
sions. The TB8 bit is cleared after each transmission.
For mode 4, this register also selects the direction (input or output)
of the SCLKx# signal.
SP0_STATUS 1F81H
SP1_STATUS 1F89H
Serial Port x Status
This register contains the serial port status bits. It has status bits for
receive overrun errors (OE), transmit buffer empty (TXE), framing
errors (FE), transmit interrupt (TI), receive interrupt (RI), and
received parity error (RPE) or received bit 8 (RB8). Reading
SPx_STATUS clears all bits except TXE; writing a byte to
SBUFx_TX clears the TXE bit.
7.3 SERIAL PORT MODES
The serial port has both synchronous and asynchronous operating modes for transmission and re-
ception. This section describes the operation of each mode.
7-4
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SERIAL I/O (SIO) PORT
7.3.1 Synchronous Modes (Modes 0 and 4)
The 8XC196MH serial port has two synchronous modes, mode 0 and mode 4. Mode 0 is the syn-
chronous mode available on all the 8XC196 devices that have serial ports. Mode 4 is an enhanced,
full-duplex synchronous mode.
7.3.1.1
Mode 0
The most common use of mode 0 is to expand the I/O capability of the device with shift registers
(see Figure 7-2). In this mode, the TXDx pin outputs a set of eight clock pulses, while the RXDx
pin either transmits or receives data. Data is transferred eight bits at a time with the least-signif-
icant bit first. Figure 7-3 shows a diagram of the relative timing of these signals. Note that only
mode 0 uses RXDx as an open-drain output.
Shift / LOAD#
VCC
Clock Inhibit
Serial In
Px.x
74HC05
15kΩ
Data
RXD
TXD
Q#
Shift Register
74HC165
Clock
Inputs
Microcontroller
VCC
Outputs
Serial
In B
Serial In A
Clock
Shift Register
74HC164
Clear
Enable#
Px.x
A0264-03
Figure 7-2. Typical Shift Register Circuit for Mode 0
In mode 0, RXDx must be enabled for receptions and disabled for transmissions. (See “Program-
ming the Control Register” on page 7-10.) When RXDx is enabled, either a rising edge on the
RXDx input or clearing the receive interrupt (RI) flag in SPx_STATUS starts a reception. When
RXDx is disabled, writing to SBUFx_TX starts a transmission.
Disabling RXDx stops a reception in progress and inhibits further receptions. To avoid a partial
or undesired complete reception, disable RXDx before clearing the RI flag in SPx_STATUS. This
can be handled in an interrupt environment by using software flags or in straight-line code by us-
ing the interrupt pending register to signal the completion of a reception.
7-5
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During a reception, the RI flag in SPx_STATUS is set after the stop bit is sampled. The RIx pend-
ing bit in the interrupt pending register is set immediately before the RI flag is set. During a trans-
mission, the TI flag is set immediately after the end of the last (eighth) data bit is transmitted. The
TIx pending bit in the interrupt pending register is generated when the TI flag in SPx_STATUS is
set.
TXD
D0
D0
D1
D1
D2
D2
D3
D3
D4
D4
D5
D5
D6
D6
D7
D7
RXD (out)
RXD (in)
Expanded:
XTAL1
TXD
RXD (out)
RXD (in)
D0
D0
D1
D2
D1
A0109-02
Figure 7-3. Mode 0 Timing
7.3.1.2
Mode 4
Mode 4 is an enhanced synchronous mode that is similar to mode 0 in many ways, but there are
three main differences:
• In mode 0, TXDx inputs or outputs the clock signal and RXDx transmits or receives data. In
mode 4, TXDx transmits data, RXDx receives data, and the SCLKx# pin inputs or outputs
the clock signal.
• For mode 4, a direction bit (DIR) was added to the SPx_CON register. This bit controls
whether SCLKx# outputs the internal shift clock or inputs an external shift clock.
• In mode 0, RXDx must be enabled to start a transmission (because it must transmit the
data). In mode 4, TXDx transmits the data, so the RXDx status is unrelated to transmissions.
Writing to SBUFx_TX starts a transmission regardless of whether RXDx is enabled.
In mode 4, SCLKx# outputs a set of eight clock pulses while TXDx transmits data, or SCLKx#
accepts a set of eight clock pulses while RXDx receives data. Data is transferred eight bits at a
time with the least-significant bit first. When SCLKx# is in output mode, its timing is identical to
that of TXDx shown in Figure 7-3. When SCLKx# is in input mode, the input shift clock signal
is internally synchronized with the internal clock.
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SERIAL I/O (SIO) PORT
In mode 4, writing to SBUFx_TX starts a transmission regardless of whether RXDx is enabled.
However, RXDx must be enabled to allow a reception. If RXDx is enabled, either a rising edge
on the RXDx input or clearing the receive interrupt (RI) flag starts a reception.
Disabling RXDx stops a reception in progress and inhibits further receptions. To avoid a partial
or undesired complete reception, disable RXDx before clearing the RI flag. This can be handled
in an interrupt environment by using software flags or in straight-line code by using the interrupt
pending register to signal the completion of a reception.
During a reception, the RI flag is set one clock bit time after the last data bit is received. The re-
ceive interrupt signal is generated immediately before the RI flag is set. During a transmission,
the TI flag is set immediately after the end of the last (eighth) data bit is transmitted. The transmit
interrupt signal is generated when the TI flag is set.
7.3.2 Asynchronous Modes (Modes 1, 2, and 3)
Modes 1, 2, and 3 are full-duplex serial transmit/receive modes, meaning that they can transmit
and receive data simultaneously. Mode 1 is the standard 8-bit, asynchronous mode used for nor-
mal serial communications. Modes 2 and 3 are 9-bit asynchronous modes typically used for in-
terprocessor communications (see “Multiprocessor Communications” on page 7-9). In mode 2,
the serial port sets an interrupt pending bit only if the ninth data bit is set. In mode 3, the serial
port always sets an interrupt pending bit upon completion of a data transmission or reception.
When the serial port is configured for mode 1, 2, or 3, writing to SBUFx_TX causes the serial
port to start transmitting data. New data placed in SBUFx_TX is transmitted only after the stop
bit of the previous data has been sent. A falling edge on the RXDx input causes the serial port to
begin receiving data if RXDx is enabled. Disabling RXDx stops a reception in progress and in-
hibits further receptions. (See “Programming the Control Register” on page 7-10.)
7.3.2.1
Mode 1
Mode 1 is the standard asynchronous communications mode. The data frame used in this mode
(Figure 7-4) consists of ten bits: a start bit (0), eight data bits (LSB first), and a stop bit (1). If
parity is enabled, a parity bit is sent instead of the eighth data bit, and parity is checked on recep-
tion.
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Stop
Start
D0
D1
D2
D3
D4
D5
D6
D7
Stop
8 Bits of Data or 7 Bits of Data
with Parity Bit
10-bit Frame
A0245-02
Figure 7-4. Serial Port Frames for Mode 1
The transmit and receive functions are controlled by separate shift clocks. The transmit shift
clock starts when the baud-rate generator is initialized. The receive shift clock is reset when a start
bit (high-to-low transition) is received. Therefore, the transmit clock may not be synchronized
with the receive clock, although both will be at the same frequency.
The transmit interrupt (TI) and receive interrupt (RI) flags in SPx_STATUS are set to indicate
completed operations. During a reception, both the RI flag and the RIx interrupt pending bit are
set just before the end of the stop bit. During a transmission, both the TI flag and the TIx interrupt
pending bit are set at the beginning of the stop bit. The next byte cannot be sent until the stop bit
is sent.
Use caution when connecting more than two devices with the serial port in half-duplex (i.e., with
one wire for transmit and receive). The receiving processor must wait for one bit time after the
RI flag is set before starting to transmit. Otherwise, the transmission could corrupt the stop bit,
causing a problem for other devices listening on the link.
7.3.2.2
Mode 2
Mode 2 is the asynchronous, ninth-bit recognition mode. This mode is commonly used with mode
3 for multiprocessor communications. Figure 7-5 shows the data frame used in this mode. It con-
sists of a start bit (0), nine data bits (LSB first), and a stop bit (1). During transmissions, setting
the TB8 bit in the SPx_CON register before writing to SBUFx_TX sets the ninth transmission bit.
The hardware clears the TB8 bit after every transmission, so it must be set (if desired) before each
write to SBUFx_TX. During receptions, the RI flag and RIx interrupt pending bit are set only if
the TB8 bit is set. This provides an easy way to have selective reception on a data link. (See “Mul-
tiprocessor Communications” on page 7-9.) Parity cannot be enabled in this mode.
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SERIAL I/O (SIO) PORT
Stop
Start
D0
D1
D2
D3
8 Bits of Data
Programmable 9th Bit
11-bit Frame
D4
D5
D6
D7
D8
Stop
A0111-01
Figure 7-5. Serial Port Frames in Mode 2 and 3
7.3.2.3
Mode 3
Mode 3 is the asynchronous, ninth-bit mode. The data frame for this mode is identical to that of
mode 2. Mode 3 differs from mode 2 during transmissions in that parity can be enabled, in which
case the ninth bit becomes the parity bit. When parity is disabled, data bits 0–7 are written to the
serial port transmit buffer, and the ninth data bit is written to SPx_CON.4 (TB8). In mode 3, a
reception always sets the RIx interrupt pending bit, regardless of the state of the ninth bit. If parity
is disabled, the SPx_STATUS register bit 7 (RB8) contains the ninth data bit. If parity is enabled,
then bit 7 (RB8) is the received parity error (RPE) flag.
7.3.2.4
Mode 2 and 3 Timings
Operation in modes 2 and 3 is similar to mode 1 operation. The only difference is that the data
consists of 9 bits, so 11-bit packages are transmitted and received. During a reception, the RI flag
and the RIx interrupt pending bit are set just after the end of the stop bit. During a transmission,
the TI flag and the TIx interrupt pending bit are set at the beginning of the stop bit. The ninth bit
can be used for parity or multiprocessor communications.
7.3.2.5
Multiprocessor Communications
Modes 2 and 3 are provided for multiprocessor communications. In mode 2, the serial port sets
the RIx interrupt pending bit only when the ninth data bit is set. In mode 3, the serial port sets the
RIx interrupt pending bit regardless of the value of the ninth bit. The ninth bit is always set in
address frames and always cleared in data frames.
One way to use these modes for multiprocessor communication is to set the master processor to
mode 3 and the slave processors to mode 2. When the master processor wants to transmit a block
of data to one of several slaves, it sends out an address frame that identifies the target slave. Be-
cause the ninth bit is set, an address frame interrupts all slaves. Each slave examines the address
byte to check whether it is being addressed. The addressed slave switches to mode 3 to receive
the data frames, while the slaves that are not addressed remain in mode 2 and are not interrupted.
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7.4 PROGRAMMING THE SERIAL PORT
To use the SIO port, you must configure the port pins to serve as special-function signals and set
up the SIO channels.
7.4.1 Configuring the Serial Port Pins
Before you can use the serial port, you must configure the associated port pins to serve as special-
function signals. Table 7-1 on page 7-2 lists the pins associated with the serial port. Table 7-2 on
page 7-2 lists the port configuration registers, and Chapter 6, “I/O Ports,” explains how to con-
figure the pins.
7.4.2 Programming the Control Register
The SPx_CON register (Figure 7-6) selects the communication mode and enables or disables the
receiver, parity checking, and nine-bit data transmissions. Selecting a new mode resets the serial
I/O port and aborts any transmission or reception in progress on the channel.
Address:
Reset State:
1F83H, 1F8BH
00H
SPx_CON
x = 0–1 (8XC196MH)
The serial port control (SPx_CON) register selects the communications mode and enables or disables
the receiver, parity checking, and nine-bit data transmission.
7
0
8XC196MH
M2
DIR
PAR
TB8
REN
PEN
M1
M0
Bit
Number
Bit
Mnemonic
Function
7
6
M2
See description for bits 0 and 1.
Synchronous Clock Direction
DIR
PAR
TB8
This bit determines the direction of the clock during synchronous mode.
0 = output
1 = input
5
4
Parity Selection Bit
This bit selects even or odd parity.
0 = even parity
1 = odd parity
Transmit Ninth Data Bit
This is the ninth data bit that will be transmitted in mode 2 or 3. This bit is
cleared after each transmission, so it must be set before SBUFx_TX is
written. When parity is enabled (SPx_CON.2 = 1), this bit takes on the
even parity value.
Figure 7-6. Serial Port Control (SPx_CON) Register
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SERIAL I/O (SIO) PORT
Address:
Reset State:
1F83H, 1F8BH
00H
SPx_CON (Continued)
x = 0–1 (8XC196MH)
The serial port control (SPx_CON) register selects the communications mode and enables or disables
the receiver, parity checking, and nine-bit data transmission.
7
0
8XC196MH
M2
DIR
PAR
TB8
REN
PEN
M1
M0
Bit
Number
Bit
Mnemonic
Function
3
REN
Receive Enable
Setting this bit enables receptions. When this bit is set, a falling edge on
the RXDx pin starts a reception in mode 1, 2, or 3. In mode 0, this bit must
be clear for transmission to begin and must be set for reception to begin.
Clearing this bit stops a reception in progress and inhibits further
receptions. To avoid a partial or undesired reception, clear this bit before
clearing the RI flag in SPx_STATUS. This can be handled in an interrupt
environment by using software flags or in straight-line code by using the
interrupt pending register to signal the completion of a reception.
2
PEN
M1:0
Parity Enable
In modes 1 and 3, setting this bit enables the parity function. This bit must
be cleared if mode 2 is used. When this bit is set, TB8 takes the parity
value on transmissions and SPx_STATUS.7 becomes the receive parity
error bit.
1:0
Mode Selection
These bits along with bit 7 select the communications mode.
M2
0
X
M1
0
0
M0
0
1
synchronous mode 0
mode 1
X
1
0
mode 2
X
1
1
mode 3
1
0
0
synchronous mode 4
Figure 7-6. Serial Port Control (SPx_CON) Register (Continued)
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7.4.3 Programming the Baud Rate and Clock Source
The SPx_BAUD register (Figure 7-7) selects the clock input for the baud-rate generator and de-
fines the baud rate for all serial I/O modes. (For mode 4 with SCLKx# configured for input, the
baud-rate generator is not used.) This register acts as a control register during write operations
and as a down-counter monitor during read operations.
WARNING
Writing to the SPx_BAUD register during a reception or transmission can
corrupt the received or transmitted data. Before writing to SPx_BAUD, check
the SPx_STATUS register to ensure that the reception or transmission is
complete.
Address:
Reset State:
1F84H, 1F8CH
0000H
SPx_BAUD
x = 0–1 (8XC196MH)
The serial port baud rate x (SPx_BAUD) register selects the serial port x baud rate and clock source.
The most-significant bit selects the clock source. The lower 15 bits represent BAUD_VALUE, an
unsigned integer that determines the baud rate.
The maximum BAUD_VALUE is 32,767 (7FFFH). In asynchronous modes 1, 2, and 3, the minimum
BAUD_VALUE is 0000H when using XTAL1 and 0001H when using BCLKx. In synchronous mode 0,
the minimum BAUD_VALUE is 0001H for transmissions and 0002H for receptions. In synchronous
mode 4, the minimum BAUD_VALUE is 0001H for both transmissions and receptions.
15
8
0
8XC196MH
CLKSRC
BV14
BV6
BV13
BV5
BV12
BV4
BV11
BV3
BV10
BV2
BV9
BV1
BV8
BV0
7
BV7
Bit
Number
Bit
Mnemonic
Function
15
CLKSRC
Serial Port Clock Source
This bit determines whether the serial port is clocked from an internal or an
external source.
0 = signal on the BCLKx pin (external source)
1 = input frequency on the XTAL1 pin (internal source)
Figure 7-7. Serial Port x Baud Rate (SPx_BAUD) Register
7-12
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SERIAL I/O (SIO) PORT
Address:
Reset State:
1F84H, 1F8CH
0000H
SPx_BAUD (Continued)
x = 0–1 (8XC196MH)
The serial port baud rate x (SPx_BAUD) register selects the serial port x baud rate and clock source.
The most-significant bit selects the clock source. The lower 15 bits represent BAUD_VALUE, an
unsigned integer that determines the baud rate.
The maximum BAUD_VALUE is 32,767 (7FFFH). In asynchronous modes 1, 2, and 3, the minimum
BAUD_VALUE is 0000H when using XTAL1 and 0001H when using BCLKx. In synchronous mode 0,
the minimum BAUD_VALUE is 0001H for transmissions and 0002H for receptions. In synchronous
mode 4, the minimum BAUD_VALUE is 0001H for both transmissions and receptions.
15
8
0
8XC196MH
CLKSRC
BV14
BV6
BV13
BV5
BV12
BV4
BV11
BV3
BV10
BV2
BV9
BV1
BV8
BV0
7
BV7
Bit
Number
Bit
Mnemonic
Function
14:0
BV14:0
These bits constitute the BAUD_VALUE.
Use the following equations to determine the BAUD_VALUE for a given
baud rate.
Synchronous mode 0:†
FXTAL1
BCLKx
-------------------------------------
Baud Rate × 2
---------------------------
BAUD_VALUE =
– 1
or
Baud Rate
Asynchronous modes 1, 2, and 3:
FXTAL1
BCLKx
Baud Rate × 8
----------------------------------------
-------------------------------------
BAUD_VALUE =
– 1 or
Baud Rate × 16
Synchronous mode 4 (SCLKx# output):
FXTAL1
-------------------------------------
BAUD_VALUE =
– 1
Baud Rate × 4
†
For mode 0 receptions, the BAUD_VALUE must be 0002H or greater.
Otherwise, the resulting data in the receive shift register will be incorrect.
Figure 7-7. Serial Port x Baud Rate (SPx_BAUD) Register (Continued)
7-13
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CAUTION
For mode 0 receptions, the BAUD_VALUE must be 0002H or greater.
Otherwise, the resulting data in the receive shift register will be incorrect.
The reason for this restriction is that the receive shift register is clocked from
an internal signal rather than the signal on TXDx. Although these two signals
are normally synchronized, the internal signal generates one clock before the
first pulse transmitted by TXDx and this first clock signal is not synchronized
with TXDx. This clock signal causes the receive shift register to shift in
whatever data is present on the RXDx pin. This data is treated as the least-
significant bit (LSB) of the reception. The reception then continues in the
normal synchronous manner, but the data received is shifted left by one bit
because of the false LSB. The seventh data bit transmitted is received as the
most-significant bit (MSB), and the transmitted MSB is never shifted into the
receive shift register.
Using XTAL1 at 16 MHz, the maximum baud rates are 2.76 Mbaud (SPx_BAUD = 8002H or
0002H) for mode 0 and 1.0 Mbaud for modes 1, 2, and 3. Table 7-3 shows the SPx_BAUD values
for common baud rates when using a 16 MHz XTAL1 clock input. Because of rounding, the
BAUD_VALUE formula is not exact and the resulting baud rate is slightly different than desired.
Table 7-3 shows the percentage of error when using the sample SPx_BAUD values. In most cases,
a serial link will work with up to a 5.0% difference in the receiving and transmitting baud rates.
Table 7-3. SPx_BAUD Values When Using XTAL1 at 16 MHz
SPx_BAUD Register Value†
% Error
Baud Rate
Mode 0
Mode 1, 2, 3
Mode 0, 4
Mode 1, 2, 3
9600
4800
2400
1200
300
8340H
8682H
8D04H
9A0AH
E82BH
8067H
80CFH
81A0H
8340H
8D04H
0.04
0.02
0.01
0
0.16
0.16
0.08
0.04
0.01
0
†
Bit 15 is always set when XTAL1 is selected as the clock source for the baud-rate generator.
7.4.4 Enabling the Serial Port Interrupts
Each serial port channel has both a transmit interrupt (TIx) and a receive interrupt (RIx). Each
channel can also generate a serial port receive error interrupt (SPx). To enable an interrupt, set the
corresponding mask bit in the interrupt mask register or peripheral interrupt mask register (see
Table 7-2 on page 7-2) and execute the EI instruction to globally enable servicing of interrupts.
See Chapter 5, “Standard and PTS Interrupts,” for more information about interrupts.
7-14
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SERIAL I/O (SIO) PORT
7.4.5 Determining Serial Port Status
You can read the SPx_STATUS register (Figure 7-8) to determine the status of the serial port.
Reading SPx_STATUS clears all bits except TXE. For this reason, we recommend that you copy
the contents of the SPx_STATUS register into a shadow register and then execute bit-test instruc-
tions such as JBC and JBS on the shadow register. Otherwise, executing a bit-test instruction
clears the flags, so any subsequent bit-test instructions will return false values. You can also read
the interrupt pending register or peripheral interrupt pending register (see Table 7-2 on page 7-2)
to determine the status of the serial port interrupts.
Address:
Reset State:
1F81H, 1F89H
00H
SPx_STATUS
x = 0–1 (8XC196MH)
The serial port status (SPx_STATUS) register contains bits that indicate the status of serial port x.
7
0
8XC196MH RPE/RB8
RI
TI
FE
TXE
OE
—
—
Bit
Number
Bit
Mnemonic
Function
7
RPE/RB8
Received Parity Error/Received Bit 8
RPE is set if parity is disabled (SPx_CON.2 = 0) and the ninth data bit
received is high.
RB8 is set if parity is enabled (SPx_CON.2 = 1) and a parity error occurred.
Reading SPx_STATUS clears this bit.
6
RI
Receive Interrupt
This bit is set when the last data bit is sampled. Reading SPx_STATUS
clears this bit.
5
TI
Transmit Interrupt
This bit is set at the beginning of the stop bit transmission. Reading
SPx_STATUS clears this bit.
4
FE
TXE
OE
—
Framing Error
This bit is set if a stop bit is not found within the appropriate period of time.
Reading SPx_STATUS clears this bit.
3
SBUFx_TX Empty
This bit is set if the transmit buffer is empty and ready to accept up to two
bytes. It is cleared when a byte is written to SBUFx_TX.
2
Overrun Error
This bit is set if data in the receive shift register is loaded into SBUFx_RX
before the previous bit is read. Reading SPx_STATUS clears this bit.
1:0
Reserved; for compatibility with future devices, write zeros to these bits.
Figure 7-8. Serial Port Status (SPx_STATUS) Register
7-15
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The receiver checks for a valid stop bit. Unless a stop bit is found within the appropriate time, the
framing error (FE) bit in the SPx_STATUS register is set. When the stop bit is detected, the data
in the receive shift register is loaded into SBUFx_RX and the receive interrupt (RI) flag is set. If
this happens before the previous byte in SBUFx_RX is read, the overrun error (OE) bit is set.
SBUFx_RX always contains the latest byte received; it is never a combination of the last two
bytes.
The receive interrupt (RI) flag indicates whether an incoming data byte has been received. The
transmit interrupt (TI) flag indicates whether a data byte has finished transmitting. These flags
also set the corresponding bits in the interrupt pending register. A reception or transmission sets
the RI or TI flag in SPx_STATUS and the corresponding interrupt pending bit. However, a soft-
ware write to the RI or TI flag in SPx_STATUS has no effect on the interrupt pending bits and
does not cause an interrupt. Similarly, reading SPx_STATUS clears the RI and TI flags, but does
not clear the corresponding interrupt pending bits. The RI and TI flags in the SPx_STATUS and
the corresponding interrupt pending bits can be set even if the RIx and TIx interrupts are masked.
The transmitter empty (TXE) bit is set if SBUFx_TX and its buffer are empty and ready to accept
up to two bytes. TXE is cleared as soon as a byte is written to SBUFx_TX. One byte may be writ-
ten if TI alone is set. By definition, if TXE has just been set, a transmission has completed and TI
is set.
The received parity error (RPE) flag or the received bit 8 (RB8) flag applies for parity enabled or
disabled, respectively. If parity is enabled, RPE is set if a parity error is detected. If parity is dis-
abled, RB8 is the ninth data bit received in modes 2 and 3.
7-16
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8
Frequency Generator
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CHAPTER 8
FREQUENCY GENERATOR
The 8XC196MD has a peripheral not found on other 8XC196Mx devices — the frequency gen-
erator. This peripheral produces a waveform with a fixed duty cycle (50%) and a programmable
frequency (ranging from 4 kHz to 1 MHz with a 16-MHz input clock). One application for the
frequency generator is to drive an infrared LED to transmit remote control data and control sig-
nals.
This chapter describes the frequency generator and explains how to configure it. For detailed de-
scriptions of the signals discussed in this chapter, refer to Appendix B, “Signal Descriptions.” For
additional information and application examples, consult AP-483, Application Examples Using
the 8XC196MC/MD Microcontroller (order number 272282).
8.1 FUNCTIONAL OVERVIEW
The frequency generator (Figure 8-1) has a frequency register, a count register, and an output sig-
nal. The output signal shares pin P7.7, so you must configure the pin for its frequency generator
output function.
8
FREQ_GEN
8
Port 7
Control
8
D
Q#
Q
Down-
Counter
Load
P7_MODE
P7_DIR
P7.7/FREQOUT
FREQ_CNT
C
P7_REG
Count = 0
A2702-01
Figure 8-1. Frequency Generator Block Diagram
8-1
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The frequency register (FREQ_GEN) controls the output frequency. The frequency generator
loads the FREQ_GEN value into the counter. The counter counts down until it reaches zero, at
which time the value is reloaded from the FREQ_GEN register. Each load toggles the D flip-flop,
producing the 50% duty cycle output. The count register (FREQ_CNT) reflects the current value
of the down-counter. Table 8-1 describes the frequency generator’s output signal and Table 8-2
describes the control and status registers.
Table 8-1. Frequency Generator Signal
Frequency
Generator
Signal
Frequency
Generator
Signal Type
Port
Pin
Description
P7.7 FREQOUT
O
Frequency Generator Output
This signal carries the output of the frequency generator.
.
Table 8-2. Frequency Generator Control and Status Registers
Mnemonic
Address
Description
FREQ_GEN
1FB8H
Frequency
The frequency register holds a programmed value that determines the
output frequency. This value is reloaded into the down-counter each time the
counter reaches 0.
FREQ_CNT
P7_DIR
1FBAH
1FD3H
Count
The read-only counter register reflects the current counter value.
Port 7 Direction
Bit 7 controls the direction of P7.7/FREQOUT. Clear this bit to configure
FREQOUT as a complementary output.
P7_MODE
P7_PIN
1FD1H
1FD7H
1FD5H
Port 7 Mode
Bit 7 controls the mode (general-purpose I/O or special-function signal) of
P7.7/FREQOUT. Set this bit to configure the pin for its FREQOUT function.
Port 7 Input
Bit 7 reflects the current state of P7.7/FREQOUT, regardless of its configu-
ration.
P7_REG
Port 7 Data Output
Bit 7 contains data to be driven out by P7.7/FREQOUT in general-purpose
I/O mode. In special-function mode, the frequency generator controls the
pin.
8-2
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FREQUENCY GENERATOR
8.2 PROGRAMMING THE FREQUENCY GENERATOR
This section explains how to configure the frequency generator and determine its status.
8.2.1 Configuring the Output
The frequency generator’s output is multiplexed with P7.7, so you must configure it as a special-
function output signal. To do so, follow this sequence:
1. Clear bit 7 of P7_DIR.
2. Set bit 7 of P7_MODE.
3. Clear bit 7 of P7_REG.
Refer to Chapter 6, “I/O Ports,” for additional information about configuring port pins.
8.2.2 Programming the Frequency
Program the frequency register (Figure 8-2) to control the frequency of the output.
Address:
Reset State:
1FB8H
00H
FREQ_GEN
(8XC196MD)
The frequency (FREQ_GEN) register holds a programmed value that specifies the output frequency.
This value is reloaded into the down-counter each time the counter reaches 0.
7
0
8XC196MD
Output Frequency
Bit
Number
Function
7:0
Output Frequency
Use the following formula to calculate the FREQ value for the desired output frequency
and write this value to the frequency register.
FXTAL1
--------------------------------------------
FREQ =
– 1
16 ×
FREQ_OUT
where:
FREQ
FXTAL1
FREQ_OUT
=
=
=
8-bit value to load into FREQ_GEN register
input frequency on XTAL1 pin, in MHz
output frequency on FREQOUT pin, in MHz
Figure 8-2. Frequency (FREQ_GEN) Register
8-3
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8.2.3 Determining the Current Value of the Down-counter
You can read the FREQ_CNT register (Figure 8-3) to determine the current value of the down-
counter.
Address:
Reset State:
1FBAH
00H
FREQ_CNT
(8XC196MD)
Read the frequency generator count (FREQ_CNT) register to determine the current value of the
down-counter.
7
0
8XC196MD
Count
Bit
Number
Function
7:0
Count
This register contains the current down-counter value.
Figure 8-3. Frequency Generator Count (FREQ_CNT) Register
8.3 APPLICATION EXAMPLE
One application for the frequency generator is to drive an infrared LED to transmit remote control
data and control signals (Figure 8-4). In this example, the frequency generator is configured with
a 40-kHz frequency and is switched on and off by writing to bit 7 of the P7_MODE register. In-
formation is transmitted serially. Zero is represented by a one-millisecond carrier burst followed
by a one-millisecond pause; one is represented by a two-millisecond carrier burst followed by a
two-millisecond pause (Figure 8-5). A photodiode receives the light pulses, and a high-pass filter
rejects low-frequency ambient light and allows the 40-kHz carrier to pass through. This carrier is
amplified and detected to reproduce the original pulse sequence.
8-4
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FREQUENCY GENERATOR
VCC
8XC196
Device
Output Signal
Filter and
Detector
P7.7
A2704-02
Figure 8-4. Infrared Remote Control Application Block Diagram
40 kHz
Zero = 2 ms
One = 4 ms
A2703-01
Figure 8-5. Data Encoding Example
This program example was designed to run on an 8XC196MD demo board. It uses an EPA timer
(timer 1) and compare channel (COMP3) to provide the timebase for the ones and zeros.
$debug
$nolist
$include (c:\ecm\196mc\mc.inc)
$list
;
;***************************************
; PROGRAM FREQ.A96
;
; This program transmits a block of data serially
; by gating the frequency generator on and off.
;
; The carrier frequency is programmed for 40 kHz.
; Ones are represented by a long (2 ms) carrier burst
; followed by a long (2 ms) pause (no carrier).
; Zeros are represented by a short (1 ms) carrier burst
8-5
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; followed by a short (1 ms) pause, thus generating a MFM waveform.
;
; This program is assembled to run on the MD demo board.
;
;**************************************
; CONSTANT AND VARIABLE DECLARATIONS
;**************************************
; Program equates
; This section defines the constants used by this program.
; They can be changed at assembly time as required.
;**************************************
;
zero_time
zero_pause_time
one_time
one_pause_time
carrier_freq
buf_size
equ
equ
equ
equ
equ
equ
equ
1000
zero_time
2000
one_time
25
8
;1 ms
;2 ms
;40 KHz
;size of data buffer (bytes)
;initial data for buffer
fill_char
;
10100011b
;**************************************
; SFR equates in a 32-byte window
; This section defines SFR locations as seen through a window
; to allow using compact read-modify-write instructions.
;**************************************
;
p2_mode_w
p2_dir_w
p2_reg_w
p2_pin_w
;
p7_mode_w
p7_dir_w
p7_reg_w
p7_pin_w
;
equ
equ
equ
equ
0f0H
0F2H
0F4H
0F6H
;WSR = 7EH 1FD0H
;WSR = 7EH 1FD2H
;WSR = 7EH 1FD4H
;WSR = 7EH 1FD6H
equ
equ
equ
equ
0f1H
0F3H
0F5H
0F7H
;WSR = 7EH 1FD1H
;WSR = 7EH 1FD3H
;WSR = 7EH 1FD5H
;WSR = 7EH 1FD7H
timer1_w
comp3_con_w
comp3_time_w
;
equ
equ
equ
0FAH
0E4H
0E6H
;WSR = 7BH 1F7AH
;WSR = 7BH 1F64H
;WSR = 7BH 1F66H
;**************************************
; Other SFR equates
; This section defines the locations of the frequency generator SFRs.
;**************************************
;
freq_gen
freq_cnt
;
equ
equ
1FB8H
1FBAH
;**************************************
; Variable storage area
; This section defines the variables used by this program.
;**************************************
;
rseg at 30h
;
rism:
dsb 13
;reserved for RISM
;
rseg at 40h
8-6
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FREQUENCY GENERATOR
;
temp:
dsw 1
dsw 1
dsw 1
dsw 1
dsb 1
dsb 1
dsb 1
temp1:
temp2:
buf_start:
buf_cnt:
bit_cnt:
flag:
;bit 0 = zero being sent
;bit 1 = one being sent
;bit 5 = get next bit
;bit 6 = get next byte
;bit 7 = buffer send in progress
;
xmit_buf:
shift_reg:
;
dsb buf_size
dsb 1
;block of data to send
;*****************************
; MAIN PROGRAM
;*****************************
; Define the program location and set up the interrupts and stack.
;*****************************
;
cseg at 0e000h
;RISM user space
;
start:
di
;set up interrupts
dpts
andb int_pend1,#10000000b;
orb int_mask1,#00000010b;unmask compare3
ld
sp,#0200h
;set up stack
;*****************************
; Initialize pin P7.7/FREQOUT for I/O and set the pin low.
;*****************************
;
ldb wsr,#7EH
;move SFR;s into window
andb p7_reg_w,#01111111b ;P7.7 = low
andb p7_dir_w,#01111111b ;P7.7 comp output
andb p7_mode_w,#01111111b;P7.7 = I/O
ldb wsr,zero_reg
;*****************************
; This section fills the data buffer with a “fill” character.
; An application would typically place a block of data here.
;*****************************
;
ld
temp,#xmit_buf
;initialize buffer data
ldb temp1,#fill_char
ldb temp2,#buf_size
stb temp1,[temp]+
djnz temp2,fill
fill:
;*****************************
; Start timer 1 with a 1 microsecond clock period,
; load the carrier frequency into FREQ_GEN, and
; enable the interrupts.
;*****************************
;
ldb temp,#11000010b
;init EPA timer1
stb temp,t1control[0] ;1 uS ticks
ldb temp,#carrier_freq ;load carrier freq
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stb temp,freq_gen[0]
ei
;into freq gen
;enable interrupts
;
;
;*****************************************
; Now send buffer out as serial data bytes
;*****************************************
; This section issues a 1 millisecond pulse on P2.0
; for use with an oscilloscope monitor.
;*****************************************
;
ld
ld
wsr,#7EH
temp,#0400
andb p2_reg_w,#11111110b ;strobe p2.0 to sync
andb p2_dir_w,#11111110b ;scope
andb p2_mode_w,#11111110b;
orb p2_reg_w,#00000001b ;set pin high
djnzw temp,$
andb p2_reg_w,#11111110b ;set pin low
ld wsr,zero_reg
;pause
;*****************************************
; Initialize the buffers and flag register that the interrupt routine needs.
;*****************************************
;
ld
ld
buf_start,#xmit_buf ;pointer reg
buf_cnt,#buf_size
;number to send
ldb flag,#11000000b
;set “buffer send in progress”
;and “get next byte” flags
;
;*****************************************
; Set the compare module’s interrupt pending bit
; to start sending the buffer. Loop until the buffer
; send is complete, then start main program over.
;*****************************************
ldb int_pend1,#00000010b;force interrupt
wait:
jbs flag,7,wait
ljmp start
;loop here until done
;then start over
;
;
;*******************************************
; COMPARE3 INTERRUPT ROUTINE
;*******************************************
; This routine executes each time the EPA compare channel times out.
; The “flag” register identifies the reason for the interrupt request.
;*******************************************
;
cseg at 0f120H
;
;comp3 Int vector demo board
pusha
;save cpu status
jbs flag,1,one_pause
jbs flag,0,zero_pause
jbs flag,5,get_bit
jbs flag,6,get_byte
sjmp all_done
;jump if one being sent
;jump if zero being sent
;get next bit
;get next byte
;if nothing set, done
;
get_byte:
andb flag,#10111111b
ldb shift_reg,[buf_start]+
ldb bit_cnt,#8
;clear get byte flag
;get byte to send into temp
;# of bits to send per char
8-8
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FREQUENCY GENERATOR
cmpb buf_cnt,#0
jne dec_buf_cnt
ljmp all_done
decb buf_cnt
;see if last byte has been sent
;no!
;yes!
dec_buf_cnt:
;decrement byte count
;
get_bit:
andb flag,#11011111b
shlb shift_reg,#1
;clear get bit flag
;shift MSB into carry flag
;send a one
jc
send_one
;else send zero
;
send_zero:
orb flag,#00000001b
ldb wsr,#7BH
;set zero's flag
;set up EPA
ldb comp3_con_w,#01000000b
add comp3_time_w,timer1_w,#zero_time
ldb wsr,#7EH
orb p7_mode_w,#10000000b
ldb wsr,zero_reg
sjmp done
;start FREQOUT
send_one:
orb flag,#00000010b
ldb wsr,#7BH
;set one's flag
;set up EPA
ldb comp3_con_w,#01000000b
add comp3_time_w,timer1_w,#one_time
ldb wsr,#7EH
orb p7_mode_w,#10000000b
ldb wsr,zero_reg
sjmp done
;start FREQOUT
;
zero_pause:
andb flag,#11111110b
ldb wsr,#7EH
;turn off zero flag
andb p7_mode_w,#01111111b
ldb wsr,#7BH
;turn off FREQOUT
;set up EPA
ldb comp3_con_w,#01000000b
add comp3_time_w,timer1_w,#zero_pause_time
ldb wsr,zero_reg
sjmp next
;
one_pause:
andb flag,#11111101b
ldb wsr,#7EH
;turn off one flag
andb p7_mode_w,#01111111b
ldb wsr,#7BH
;turn off FREQOUT
;set up EPA
ldb comp3_con_w,#01000000b
add comp3_time_w,timer1_w,#one_pause_time
ldb wsr,zero_reg
;
next:
decb bit_cnt
;decrement bit count
cmpb bit_cnt,#00H
jne next1
orb flag,#01000000b
sjmp done
;check if 8 bits sent
;no, get next bit
;yes, get next byte
;done for now
next1:
orb flag,#00100000b
sjmp done
;set get bit flag
;
all_done:
done:
ldb flag,#00H
popa
ret
;clear all flags
;
end
8-9
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9
Waveform Generator
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CHAPTER 9
WAVEFORM GENERATOR
A waveform generator simplifies the task of generating synchronized, pulse-width modulated
(PWM) outputs. This waveform generator is optimized for motion control applications such as
driving 3-phase AC induction motors, 3-phase DC brushless motors, or 4-phase stepping motors.
The waveform generator can produce three independent pairs of complementary PWM outputs
that share a common carrier period, dead time, and operating mode. Once it is initialized, the
waveform generator operates without CPU intervention unless you need to change a duty cycle.
This chapter describes the waveform generator and explains how to configure it. For detailed de-
scriptions of the signals discussed in this chapter, refer to Appendix B, “Signal Descriptions.” For
additional information and application examples, consult AP-483, Application Examples Using
the 8XC196MC/MD Microcontroller (order number 272282).
9.1 WAVEFORM GENERATOR FUNCTIONAL OVERVIEW
The waveform generator (Figure 9-1) has three main parts: a timebase generator, phase driver
channels, and control circuitry. The timebase generator establishes the carrier period, the phase
driver channels determine the duty cycle, and the control circuitry determines the operating mode
and controls interrupt generation. The waveform generator’s maximum frequency is 15.625 kHz
for center-aligned modes and 31.250 kHz for edge-aligned modes.
There are three independent phases, each of which has two programmable, complementary out-
puts. A programmable “dead-time” generator prevents the complementary outputs from being ac-
tive at the same time. The carrier period, dead time, and operating mode are the same for all three
phases; the duty cycle is independently programmable.
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Timebase Generator
16
16
WG_RELOAD
Buffer
Update WG_RELOAD
WG_RELOAD
16
WG_COUNTER = 1
WG Interrupt
WG_COUNTER = WG_RELOAD
Reload
Comparator
WG_COUNTER
16
To Other Phase Driver Channels
Phase Driver
One of Three Channels
P6.0 / WG1#
Dead-time
Phase
&
Comparator
Output
Circuitry
P6.1 / WG1
16
16
16
WG_COMPx
Buffer
Update WG_COMP
WG_COMPx
Control
16
16
8
WG_OUTPUT
Buffer
WG_OUTPUT
Update WG_OUTPUT
Output Control
16
8
Mode Control Signals
and Dead Time
WG_CONTROL
WG_PROTECT
Output Disable
8
8
Protection
Circuitry
EXTINT Interrupt Vector
EXTINT Input Pin
A2637-01
Figure 9-1. Waveform Generator Block Diagram
9-2
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WAVEFORM GENERATOR
9.2 WAVEFORM GENERATOR SIGNALS AND REGISTERS
Table 9-1 describes the waveform generator’s signals, and Table 9-2 briefly describes the control
and status registers.
Table 9-1. Waveform Generator Signals
Waveform
Port
Pin
Generator
Signal
Type
Description
P6.0
WG1#
O
O
O
O
O
O
I
Waveform generator phase 1 negative output.
Waveform generator phase 1 positive output.
Waveform generator phase 2 negative output.
Waveform generator phase 2 positive output.
Waveform generator phase 3 negative output.
Waveform generator phase 3 positive output.
Input to the waveform generator’s protection circuitry.
P6.1
P6.2
P6.3
P6.4
P6.5
—
WG1
WG2#
WG2
WG3#
WG3
EXTINT
.
Table 9-2. Waveform Generator Control and Status Registers
Mnemonic
Address
Description
INT_MASK1
0013H
Interrupt Mask 1
The EXTINT bit enables or disables the EXTINT interrupt.
8XC196MH: The WG bit enables or disables the waveform generator
interrupt.
8XC196MC, MD: The PI bit enables or disables the multiplexed peripheral
interrupt. The corresponding bit in the PI_MASK register enables or disables
the individual sources of the peripheral interrupt.
INT_PEND1
0014H
Interrupt Pending 1
Any set bit indicates a pending interrupt request.
PI_MASK
(MC, MD)
1FBCH
Peripheral Interrupt Mask
8XC196MC, MD: The WG bit enables or disables the waveform generator
interrupt as one of the possible sources of the multiplexed peripheral
interrupt. The PI bit in INT_MASK1 must be set to enable the multiplexed
peripheral interrupt.
PI_PEND
(MC, MD)
1FBEH
Peripheral Interrupt Pending
Any set bit indicates a pending interrupt request.
WG_COMP1
WG_COMP2
WG_COMP3
1FC2H
1FC4H
1FC6H
Waveform Generator Compare Buffers
Each phase compare buffer contains a value that is compared with the
counter value. The action that is performed when a match occurs depends
on the operating mode.
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Table 9-2. Waveform Generator Control and Status Registers (Continued)
Mnemonic
Address
Description
WG_CONTROL 1FCCH
Waveform Generator Control
The control register determines the waveform generator’s operating mode,
starts and stops the counter, specifies the dead time for all phases, and
indicates the current count direction.
WG_COUNTER 1FCAH
Waveform Generator Count Value
The read-only counter register reflects the current counter value.
WG_OUTPUT
1FC0H
Waveform Generator Output Control
The output control register configures the waveform generator’s outputs and
selects their active polarity.
WG_PROTECT 1FCEH
Waveform Generator Protection
The protection register enables and disables the protection circuitry and the
outputs, selects level-sensitive or edge-triggered interrupts, and controls
which value of the edge or level will trigger an interrupt request.
8XC196MH only: This register also selects the method for disabling the
outputs: inactive states or weak pull-ups.
WG_RELOAD
1FC8H
Waveform Generator Reload Value
The reload register contains a value that is compared with the counter value.
The actions performed based on this comparison depend on the operating
mode.
9.3 WAVEFORM GENERATOR OPERATION
This section describes the major components of the waveform generator: the timebase generator,
the phase driver channels, and the control and protection circuitry. It also explains how the buff-
ered registers are updated and describes the similarities and differences between the center-
aligned and edge-aligned operating modes. Finally, it describes the two types of interrupt requests
that the waveform generator can generate and explains how to enable the interrupts.
9.3.1 Timebase Generator
The timebase generator establishes the carrier period of the PWM outputs. You specify this period
by writing a value to the reload register (WG_RELOAD). This value is loaded into the counter
register (WG_COUNTER) when the system is initialized and periodically (depending on the op-
erating mode) thereafter. You can read the counter register to determine the current counter value
and you can write to the reload register to change the reload value at any time.
The 16-bit timebase counter is clocked every state time. The control register (WG_CONTROL)
enables and disables the counter, controls the counting mode, and reflects the count direction.
When the counter is enabled, it continuously counts between 0001H and the reload value. Writing
0000H to the reload register or clearing the enable bit in the control register stops the counter.
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WAVEFORM GENERATOR
9.3.2 Phase Driver Channels
The phase driver channels determine the duty cycle of the outputs. You specify the duty cycle by
writing a value to each phase’s compare register (WG_COMPx). In all operating modes, the out-
puts are initially asserted, and they remain asserted until the counter value (WG_COUNTER)
matches the phase’s compare register (WG_COMPx) value. At this point, the outputs are deas-
serted and remain deasserted until another event occurs. The event that causes the outputs to be
asserted again depends on the operating mode. (See “Operating Modes” on page 9-7.)
The dead-time generator circuitry (Figure 9-2) prevents an output and its complement from being
asserted at the same time. It uses two internal signals, WFG and DT, to generate the nonoverlap-
ping outputs. The edge-detection circuitry generates the WFG signal, while a 10-bit dead-time
counter generates the DT signal. When a valid edge is detected, the dead-time counter is loaded
with the 10-bit dead-time value from the control register and DT is driven low. The counter dec-
rements once every state time until it reaches zero, at which point the counter stops and DT is
driven high. The WFG signal is ANDed with DT to produce the WG_EVEN signal; the WFG#
signal is ANDed with DT to produce the WG_ODD signal. The waveform generator’s outputs
can be connected to the WG_EVEN and WG_ODD signals. (See “Configuring the Outputs” on
page 9-12.)
Output Disable
From
Protection Circuit
10-Bit Value
WG_CONTROL
Bits 0 – 9
To Other
Channels
WG_EVEN
Transition
Detector
From
Phase
Comparator
P6.0 / WG1#
P6.1 / WG1
10-Bit Counter
Start/ CNT=0
Load
DT
Output
Circuitry
Trigger
Both
Edges
WG_ODD
WFG
WFG#
A2640-01
Figure 9-2. Dead-time Generator Circuitry
9.3.3 Control and Protection Circuitry
The control circuitry contains the control (WG_CONTROL) and output (WG_OUTPUT) regis-
ters. The control register enables or disables the counter, specifies the count direction, controls
the operating mode, and specifies the dead time for all three phases. The output register config-
ures the pins, specifies the output polarity (active high or active low), and controls whether the
outputs are updated immediately or are synchronized with an event.
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The protection circuitry (Figure 9-3) monitors the EXTINT pin. When it detects a valid event on
the input, it simultaneously disables the outputs and generates an EXTINT interrupt request. Soft-
ware can also disable the outputs by clearing the enable outputs (EO) bit in the protection
(WG_PROTECT) register.
For the 8XC196MC and 8XC196MD, disabled outputs go to their inactive states based on the
programmed polarity. The protection circuitry of the 8XC196MH operates in the same way as
that of the 8XC196MC and 8XC196MD, but it allows you to choose the method used to disable
the outputs. It can either place outputs in their inactive states, as the other devices do, or it can
apply weak pull-ups to them. The protection type (PT) bit in the protection register controls the
method.
ES, IT
EXTINT
Interrupt
Request
DP
EO Bit
Register
Falling
Rising
00
01
Pulse
Transition
Detector
R
Q
S
OD#
EXTINT
FXTAL1
Low
10
11
Level
Sampler
High
CPU Write EO
CPU Read EO
CPU Bus
A2661-01
Figure 9-3. Protection Circuitry
9.3.4 Register Buffering and Synchronization
The WG_RELOAD, WG_COMPx, and WG_OUTPUT registers are buffered; you read and write
the buffers rather than the registers. The waveform generator updates the registers synchronously
to prevent erroneous or nonsymmetrical duty cycles.
When you write to the WG_COMPx buffers while the counter is stopped (either when the counter
register is zero or when the enable counter bit in the control register is clear), the registers are
updated one-half state time later.
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WAVEFORM GENERATOR
The WG_RELOAD register is updated when the counter value reaches the reload value. The
WG_COUNTER register is loaded with the updated WG_RELOAD value, so a new reload value
takes effect for the next cycle. In mode 3 (and mode 4 for the 8XC196MH), the WG_RELOAD
register can be updated when an EPA event occurs. This requires you to enable an EPA channel’s
peripheral function. (See Chapter 11, “Event Processor Array (EPA)” for details.)
The WG_OUTPUT register contains a synchronization bit that controls whether changes to the
output signals are reflected immediately or are synchronized with an event. The synchronization
bit is not buffered, so changes to it take effect immediately. You should initialize the synchroni-
zation to zero (changes take effect immediately) to ensure that the pins are in the desired states
when the counter starts.
9.3.5 Operating Modes
The waveform generator can operate in a center-aligned or an edge-aligned mode. In the center-
aligned modes, the counter counts both up and down; in the edge-aligned modes, it counts up
only. The center-aligned modes generate PWM outputs that are more efficient for driving 3-phase
AC induction motors, while the edge-aligned modes generate conventional PWM outputs. Cen-
ter-aligned outputs have less harmonic content than edge-aligned outputs, with effectively twice
the carrier period.
The initial condition of the waveform generator is the same for all operating modes. Following a
system power-up or reset, the counter is stopped, outputs are deasserted, and all registers are
cleared. Values written to the registers take effect one-half state time later.
The main differences between center-aligned and edge-aligned modes are the counter’s initial
value, the count direction, and the conditions that cause a change in the state of the outputs. Table
9-3 summarizes the operation of the center-aligned and edge-aligned modes.
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Table 9-3. Operation in Center-aligned and Edge-aligned Modes
Step
Center-aligned Modes
Edge-aligned Modes
1
Load WG_COUNTER with WG_RELOAD.
Leave outputs deasserted.
Load WG_COUNTER with 0001H.
Leave outputs deasserted.
2
3
When counter is enabled, begin counting down. When counter is enabled, begin counting up.
Assert outputs when up count begins.
When WG_COUNTER reaches 1, wait 1 state,
then begin counting up. Assert outputs when up
count begins.
When WG_COUNTER reaches the
When WG_COUNTER reaches the
WG_COMPx value during the up count, deassert WG_COMPx value, deassert the corresponding
the corresponding phase’s outputs and continue phase’s outputs and continue counting up.
counting up.
4
5
When WG_COUNTER reaches the
WG_RELOAD value, begin counting down.
When WG_COUNTER reaches the
WG_RELOAD value, update WG_RELOAD and
go to step 1.
When WG_COUNTER reaches the
WG_COMPx value during the down count,
assert the corresponding phase’s outputs and
continue counting down.
6
When WG_COUNTER reaches 1, deassert
outputs, update WG_RELOAD, and go to step 1.
The main differences between the center-aligned modes and among the edge-aligned modes are
the events that control register updates. Table 9-4 lists the events that can cause register updates
and the registers that are updated in each mode.
Table 9-4. Register Updates
Center-aligned Modes
Edge-aligned Modes
Mode 3
Mode 4
(MH Only)
Event
Mode 0
Mode 1
Mode 2
Registers Updated
Registers Updated
WG_RELOAD
WG_COUNTER
WG_COMPx
WG_RELOAD
WG_COUNTER
WG_COMPx
WG_RELOAD
WG_COUNTER
WG_COMPx
WG_RELOAD
WG_COUNTER
WG_COMPx
WG_RELOAD
WG_COUNTER
WG_COMPx
WG_COUNTER
= WG_RELOAD
WG_OUTPUT†
WG_OUTPUT†
WG_OUTPUT†
WG_OUTPUT†
WG_OUTPUT†
WG_COUNTER = 1
—
WG_COMPx
—
—
—
WG_OUTPUT†
WG_OUTPUT†
WG_OUTPUT†
WG_RELOAD
WG_COUNTER
WG_COMPx
WG_OUTPUT†
EPA event
WG_OUTPUT†
†
The WG_OUTPUT register is updated under these conditions if its synchronization bit is set;
otherwise, changes take effect immediately.
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WAVEFORM GENERATOR
9.3.5.1
Center-aligned Modes
In the center-aligned modes, the counter counts down from the WG_RELOAD value to 1, then
counts back up from 1 to WG_RELOAD. When you write to the WG_RELOAD register,
WG_COUNTER is loaded with the reload value. When you set the enable bit in the control reg-
ister, the counter begins counting down and continues counting until it reaches 1, waits one state
time, and starts counting up until it reaches WG_RELOAD. At this point, WG_RELOAD is up-
dated and WG_COUNTER is reloaded with the updated value, so a new reload value takes effect
for the next cycle. The counter resumes counting down from WG_RELOAD to 1. This produces
a symmetrical ascending and descending count, illustrated by the triangular wave in Figure 9-4,
with a period that is twice the WG_RELOAD value. Figure 9-5 shows the operation of outputs
and interrupts in center-aligned modes.
WG_RELOAD
Changed
Counter
Enabled
WG_COUNTER =
WG_RELOAD
WG_COUNTER
Value
1
0
Carrier Period
Reset
Write to WG_RELOAD
A2636-01
Figure 9-4. Center-aligned Modes — Counter Operation
In mode 0, the WG_COMPx and WG_OUTPUT registers are updated only once during the car-
rier period, when the counter reaches the reload value. In mode 1, these registers are updated
twice during the carrier period: first when the counter is set to 1, then again when it reaches the
reload value.
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WG_COMPx
WG_COUNTER
1
WG_COUNTER
=WG_COMPx
WG Interrupt
P6.0 / WG1#
Note:
Carrier period and duty cycle both
change since WG_COMP is not changed.
x
P6.1 / WG1
Mode 0, OP0 = OP1 = 1, PH1.0 = PH1.1 = PH1.2 = 1
= Additional interrupt in mode 1 only.
A2641-01
Figure 9-5. Center-aligned Modes — Output Operation
Edge-Aligned Modes
9.3.5.2
In the edge-aligned modes, the counter begins at 1 and counts up to the WG_RELOAD value.
When you write to the WG_RELOAD register, WG_COUNTER is loaded with 0001H. When
you set the enable bit in the control register, the counter begins counting up and continues count-
ing until it reaches the WG_RELOAD value or, in mode 3 only, until an EPA event occurs. At
this point, WG_COUNTER is reloaded with 0001H and WG_RELOAD is updated, so a new re-
load value takes effect for the next cycle. The counter resumes counting up from 0001H to
WG_RELOAD. This produces a smoothly ascending count, illustrated by the sawtooth wave in
Figure 9-6, with a period that is equal to the WG_RELOAD value. Figure 9-7 shows the operation
of outputs and interrupts in edge-aligned modes.
In mode 2, the registers are updated only once during the carrier period, when the counter reaches
the reload value. In mode 3, the registers are also updated when an EPA peripheral function event
occurs. (You must configure an EPA channel for this function. See Chapter 11, “Event Processor
Array (EPA)” for information.)
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WAVEFORM GENERATOR
WG_RELOAD
Updated
EPA Event
(Mode 3 Only)
WG_RELOAD
Value
Counter
Enabled
WG_COUNTER
Value
1
0
Carrier
Period
Reset
Write to WG_RELOAD
A2639-01
Figure 9-6. Edge-aligned Modes — Counter Operation
EPA Event
WG_COMPx
WG_COUNTER
1
Carrier
Period
WG_COUNTER
=WG_COMP
WG Interrupt
P6.0 / WG1#
Note:
Carrier period and duty cycle both
change since WG_COMPx is not changed.
P6.1 / WG1
Mode 3, OP0 = OP1 = 1, PH1.0 = PH1.1 = PH1.2 = 1
A2653-01
Figure 9-7. Edge-aligned Modes — Output Operation
8XC196MH only: The 8XC196MH device has an additional edge-aligned mode, mode 4. This
mode prevents the output “jitter” that can occur in mode 3 when an EPA event reloads
WG_COUNTER, which also causes a change in the duty cycle. In mode 4, an EPA event reloads
WG_OUTPUT, but WG_COMPx and WG_COUNTER are reloaded only when the counter
reaches the reload value.
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9.4 PROGRAMMING THE WAVEFORM GENERATOR
This section explains how to configure the waveform generator and determine its status.
9.4.1 Configuring the Outputs
The waveform generator’s outputs are multiplexed with general-purpose output port 6, so you
must configure them as special-function signals to use them as waveform-generator outputs. The
WG_OUTPUT register (Figure 9-8) configures the pins, establishes the output polarity, and con-
trols whether changes to the outputs are synchronized with an event or take effect immediately.
Four bits of WG_OUTPUT are unrelated to the waveform generator; they configure the outputs
for the pulse-width modulator (PWM) peripheral, which also shares pins with port 6. The P6 and
PE6 bits control the P6.6/PWM0 pin, and the P7 and PE7 bits control the P6.7/PWM1 pin. Their
placement in this register allows you to configure all the port 6 pins with a single write to
WG_OUTPUT.
Table 9-5 shows the bit combinations necessary to drive the waveform generator’s outputs high
or low or to connect them to the WG_EVEN or WG_ODD signal. Note that PHx.2 is always set
to select the waveform-generator signal function (clearing PHx.2 selects the general-purpose I/O
port function). The “Output Polarities” column shows the output polarities. The drawings show
a duty cycle of about 15%, and for these cases, the high portion of the waveforms increases as
dead time increases.
,
Table 9-5. Output Configuration
Output Values
WGx WGx#
Output Polarities
PHx.2 PHx.1 PHx.0
WGx
WGx#
1
1
0
0
0
1
Low
Low
Always Low
Always Low
Low
WG_EVEN#
Always Low
1
1
1
1
0
1
WG_ODD
Low
Always Low
WG_ODD WG_EVEN
NOTE: This table assumes active-high outputs (OP1=OP0=1).
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WAVEFORM GENERATOR
Address:
Reset State:
1FC0H
0000H
WG_OUTPUT (Waveform Generator)
The waveform generator output configuration (WG_OUTPUT) register controls the configuration of
the waveform generator and PWM module pins. Both the waveform generator and the PWM module
share pins with port 6. Having these control bits in a single register enables you to configure all port 6
pins with a single write to WG_OUTPUT.
15
8
OP1
P7
OP0
P6
SYNC
PH3.1
PE7
PE6
PH3.2
PH2.0
PH2.2
PH1.1
PH1.2
PH1.0
7
0
PH3.0
PH2.1
Bit
Number
Bit
Mnemonic
Function
15
OP1
Output Polarity
Selects the output polarity for negative-phase outputs WG1#, WG2#,
and WG3#.
0 = active-low outputs
1 = active-high outputs
14
13
OP0
Output Polarity
Selects the output polarity for positive-phase outputs WG1, WG2, and
WG3.
0 = active-low outputs
1 = active-high outputs
SYNC
Synchronize
Selects whether updating the WG_OUTPUT register is synchronized
with another event or occurs immediately after you change it.
0 = update WG_OUTPUT immediately
1 = synchronize WG_OUTPUT update with an event
To ensure that the outputs are in the desired states when the waveform
generator starts, you should initially clear this bit, then set it later if you
want subsequent WG_OUTPUT updates to be synchronized with an
event. (Table 9-4 on page 9-8 lists the events that update WG_OUTPUT
in each mode.)
12
11
PE7
PE6
P6.7/PWM1 Function
Selects the port function or the PWM output function of P6.7/PWM1.
0 = P6.7
1 = PWM1
P6.6/PWM0 Function
Selects the port function or the PWM output function of P6.6/PWM0.
0 = P6.6
1 = PWM0
Figure 9-8. WG Output Configuration (WG_OUTPUT) Register
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Address:
Reset State:
1FC0H
0000H
WG_OUTPUT (Waveform Generator) (Continued)
The waveform generator output configuration (WG_OUTPUT) register controls the configuration of
the waveform generator and PWM module pins. Both the waveform generator and the PWM module
share pins with port 6. Having these control bits in a single register enables you to configure all port 6
pins with a single write to WG_OUTPUT.
15
8
OP1
P7
OP0
P6
SYNC
PH3.1
PE7
PE6
PH3.2
PH2.0
PH2.2
PH1.1
PH1.2
PH1.0
7
0
PH3.0
PH2.1
Bit
Number
Bit
Mnemonic
Function
10
PH3.2
Phase 3 Function
Selects either the port function or the waveform generator output
function for pins P6.4/WG3# and P6.5/WG3.
0 = P6.4, P6.5
1 = WG3#, WG3
9
8
PH2.2
PH1.2
Phase 2 Function
Selects either the port function or the waveform generator output
function for pins P6.2/WG2# and P6.3/WG2.
0 = P6.2, P6.3
1 = WG2#, WG2
Phase 1 Function
Selects either the port function or the waveform generator output
function for pins P6.0/WG1# and P6.1/WG1.
0 = P6.0, P6.1
1 = WG1#, WG1
7
P7
P6.7/PWM1 Value
Write the desired P6.7/PWM1 value to this bit.
6
P6
P6.6/PWM0 Value
Write the desired P6.6/PWM0 value to this bit.
5:4
PH3.1:0
P6.4/WG3#, P6.5/WG3 Value
Write the desired output values to these bits. See Table 9-5 on page
9-12.
3:2
1:0
PH2.1:0
PH1.1:0
P6.2/WG2#, P6.3/WG2 Values
Write the desired output values to these bits. See Table 9-5 on page
9-12.
P6.0/WG1#, P6.1/WG1 Values
Write the desired output values to these bits. See Table 9-5 on page
9-12.
Figure 9-8. WG Output Configuration (WG_OUTPUT) Register (Continued)
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9.4.2 Controlling the Protection Circuitry and EXTINT Interrupt Generation
The protection register (Figure 9-9) controls the protection circuitry and EXTINT interrupt re-
quests.
Address:
Reset State (MC, MD)
Reset State (MH):
1FCEH
F0H
WG_PROTECT
E0H
The waveform protection (WG_PROTECT) register enables and disables the outputs and the
protection circuitry. It also selects either level-sensitive or edge-triggered EXTINT interrupts, and
selects which level or edge will generate an EXTINT interrupt request.
7
0
0
8XC196MC, MD
8XC196MH
—
—
—
—
—
—
—
ES
ES
IT
IT
DP
DP
EO
EO
7
PT
Bit
Number
Bit
Mnemonic
Function
7:5
—
Reserved; for compatibility with future devices, write zeros to these bits.
6†
PT
Protection Type
This bit selects the method used for disabling the outputs.
0 = inactive states
1 = weak pull-ups
3:2
ES
IT
Enable Sampling and Interrupt Type
The ES bit selects whether the protection circuitry samples the EXTINT
signal level or detects a signal transition (edge), while the IT bit controls
which value of the edge or level triggers an interrupt request. The
possible combinations are as follows.
ES
IT
Event
0
0
1
1
0
1
0
1
falling edge
rising edge
low level
high level
1
DP
EO
Disable Protection
This bit enables and disables the protection circuitry.
0 = enable protection
1 = disable protection
0
Enable Outputs
This bit enables and disables the outputs.
0 = disable outputs
1 = enable outputs
†
On the 8XC196MC, MD devices, this bit is reserved. For compatibility with future devices, always
write as zero.
Figure 9-9. Waveform Generator Protection (WG_PROTECT) Register
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9.4.3 Specifying the Carrier Period and Duty Cycle
The reload register (WG_RELOAD) and the phase compare registers (WG_COMPx) control the
carrier period and duty cycle. Write a value to the reload register (Figure 9-10) to establish the
carrier period. Write a value to each phase compare register to specify the length of time that the
associated outputs will remain asserted.
Address:
Reset State:
1FC8H
0000H
WG_RELOAD
The waveform generator reload (WG_RELOAD) register and the phase compare registers
(WG_COMPx) control the carrier period and duty cycle. Write a value to the reload register to
establish the carrier period.
Changing the WG_RELOAD value changes both the carrier period and the duty cycle because the
outputs remain asserted for a constant length of time, while the counter takes longer to cycle. To
change the carrier period without changing the duty cycle, you must proportionally change both
WG_RELOAD and WG_COMPx at the same time, immediately after the interrupt.
15
0
Reload
Bit
Number
Function
15:0
Reload
This register determines the carrier period.
Use the following formulas to calculate carrier period and duty cycle.
multiplier × WG_RELOAD
--------------------------------------------------------------------
TCARRIER
=
FXTAL1
WG_COMPx
WG_RELOAD
-------------------------------------
Duty Cycle =
× 100%
where:
TCARRIER
=
=
=
=
=
carrier period, in µs
FXTAL1
input frequency on XTAL1 pin, in MHz
4 for center-aligned modes; 2 for edge-aligned modes
16-bit WG_RELOAD value ≥ WG_COMPx
16-bit WG_COMPx value ≤ WG_RELOAD
multiplier
WG_RELOAD
WG_COMPx
Figure 9-10. Waveform Generator Reload (WG_RELOAD) Register
9-16
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WAVEFORM GENERATOR
Address: 1FC2H,1FC4H,1FC6H
Reset State: 0000H
WG_COMPx
x = 1–3
The phase compare (WG_COMPx) register controls the duty cycle of each phase. Write a value to
each phase compare register to specify the length of time that the associated outputs will remain
asserted.
Changing the WG_RELOAD value changes both the carrier period and the duty cycle because the
outputs remain asserted for a constant length of time, while the counter takes longer to cycle. To
change the carrier period without changing the duty cycle, you must proportionally change both
WG_RELOAD and WG_COMPx at the same time, immediately after the interrupt.
15
0
Compare
Bit
Number
Function
15:0
Compare
These bits determine the length of time that the associated outputs are asserted.
Use the following formulas to calculate output assertion time and duty cycle.
multiplier × WG_COMPx
----------------------------------------------------------------
TOUTPUT
=
FXTAL1
WG_COMPx
-------------------------------------
Duty Cycle =
× 100%
WG_RELOAD
where:
TOUTPUT
=
=
=
=
=
total time output is asserted, in µs
FXTAL1
input frequency on XTAL1 pin, in MHz
multiplier
WG_RELOAD
WG_COMPx
4 for center-aligned modes; 2 for edge-aligned modes
16-bit WG_RELOAD value ≥ WG_COMPx
16-bit WG_COMPx value ≤ WG_RELOAD
Figure 9-11. Phase Compare (WG_COMPx) Register
9.4.4 Specifying the Operating Mode and Dead Time and Starting the Counter
The control register (Figure 9-12) specifies the dead time and operating mode and enables and
disables the counters. A read-only bit (CS) indicates the current count direction.
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WG_CONTROL
Address:
Reset State (MC, MD):
Reset State (MH):
1FCCH
00C0H
8000H
The waveform generator control (WG_CONTROL) register controls the operating mode, dead time,
and count direction, and enables and disables the counter.
15
8
0
—
M2
M1
M0
CS
EC
DT9
DT1
DT8
DT0
7
DT7
DT6
DT5
DT4
DT3
DT2
Bit
Bit
Mnemonic
Function
Number
15
14:12
—
Reserved; for compatibility with future devices, write zero to this bit.
M2:0
Operating Mode
This field controls the waveform generator’s operating mode.
M2
M1
M0
Mode
0
0
0
0
1
0
0
1
1
1
0
1
0
1
1
0
1
2
3
4
center-aligned; update registers once
center-aligned; update registers twice
edge-aligned; update registers once
edge-aligned; update registers twice
(8XC196MH only) edge-aligned; update
WG_COMPx and WG_COUNTER only when
WG_COUNTER = WG_RELOAD
11
CS
Counter Status
This read-only bit indicates whether the counter is counting up or
counting down.
0 = down counting
1 = up counting
10
EC
Enable Counter
This bit starts and stops the counter.
0 = disable (stop) counter
1 = enable (start) counter
9:0
DT9:0
Dead-time
This field specifies the dead-time for all three phases. Use the following
formula to calculate the appropriate DT_VALUE.
TDEAD × FXTAL1
------------------------------------------
DT_VALUE =
2
where:
TDEAD = dead-time, in µs
XTAL1 = input frequency on XTAL1 pin, in MHz
F
Figure 9-12. Waveform Generator Control (WG_CONTROL) Register
9-18
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WAVEFORM GENERATOR
9.5 DETERMINING THE WAVEFORM GENERATOR’S STATUS
Read WG_CONTROL (Figure 9-12 on page 9-18) to determine the current dead-time value,
counter status, count direction, and operating mode. Read WG_COUNTER (Figure 9-13) to de-
termine the current counter value.
Address:
Reset State (MC, MD):
Reset State (MH):
1FCAH
XXXXH
0000H
WG_COUNTER
You can read the waveform generator counter (WG_COUNTER) register to determine the current
counter value.
15
0
Counter Value
Bit
Number
Function
15:0
Counter Value
This register reflects the current counter value.
Figure 9-13. Waveform Generator Counter (WG_COUNTER) Register
9.6 ENABLING THE WAVEFORM GENERATOR INTERRUPTS
The waveform generator can generate two types of interrupt requests. The WG interrupt request
is triggered by the counter, while the EXTINT interrupt is triggered by an external event.
Mode 0 generates a WG interrupt request once per period, when the counter reaches the
WG_RELOAD value. Mode 1 generates a WG interrupt request twice per period, first when the
counter reaches 1 and again when it reaches the WG_RELOAD value. The edge-aligned modes
generate a WG interrupt request once at the end of each period, when the counter is reloaded with
1.
The protection circuitry controls the EXTINT interrupt. Two bits in the protection register control
the type of external event that will generate an interrupt request: a falling or rising edge or a low
or high level. (See “Controlling the Protection Circuitry and EXTINT Interrupt Generation” on
page 9-15.)
The edge detection circuitry requires a signal to remain asserted for at least 2 state times to be
considered a valid edge. The sample circuitry requires a signal to remain asserted for at least 24
state times to be considered a valid level. It samples the input level 3 times during this 24-state
period and recognizes the signal as valid only if it is asserted for each sample. Level sampling is
useful for environments in which noise spikes might cause unintended interrupts if edge detection
were used.
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To enable the interrupts, set the corresponding mask bits in the mask register (see Table 9-2 on
page 9-3) and execute the EI instruction to enable interrupt servicing. You can read the interrupt
pending register to determine whether there are any pending interrupts. Refer to Chapter 5, “Stan-
dard and PTS Interrupts” for details.
9.7 DESIGN CONSIDERATIONS
This section describes design and programming considerations for using the waveform generator.
9.7.1 Dead Time and Duty Cycle
Short dead times have little effect on the duty cycle if the pulse is relatively wide; however, longer
dead times with narrower pulses can affect the duty cycle (Figure 9-14). No minimum pulse width
is imposed by the hardware, so it is possible to deassert an output for the entire period if the total
dead time is greater than the pulse width. For this reason, software should ensure that the pulse
width is at least 3 × TDEAD
.
WG_COUNT
1
Dead Time
Increased
Dead Time
Increased
WG_COUNT=
WG_COMP
Dead Time
(DT)
WFG
P6.0 / WG1#
=DT x WFG#
P6.1 / WG1
=DT x WFG
No WFG1 Output
Mode 0, OP0 = OP1 = 1, PH1.0 = PH1.1 = PH1.2 = 1
= Power Output Driver Enabled
= Dead Time
A2660-01
Figure 9-14. Effect of Dead Time on Duty Cycle
9-20
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WAVEFORM GENERATOR
9.7.2 EXTINT Interrupts and Protection Circuitry
The protection register contains two bits, disable protection (DP) and enable output (EO), that to-
gether enable and disable the waveform generator’s outputs. The EXTINT event generates a sin-
gle short pulse that clears the EO bit, so if software sets the EO bit immediately following an
EXTINT event, the outputs will be disabled only for the time between the EXTINT event and the
CPU write. The CPU can immediately set the EO bit again, even if the EXTINT signal remains
asserted.
9.8 PROGRAMMING EXAMPLE
This example was designed to run on an 8XC196MC demo board, but it can easily be modified
for an evaluation board. The program allows you to test the waveform generator’s registers and
observe their effects on the output waveforms. All variables are defined as words and are masked
to the appropriate length before they are written to the registers. (This method is not compact, but
it is easy to code and debug.) When running the program under the reduced instruction set mon-
itor (RISM) software, you can use the following command to change any variable and immedi-
ately see the result on the outputs:
WORD.variable_name
$debug
;Program to test WFG peripheral
;
$nolist
$include (c:\ecm\196mc\mc.inc)
$list
;
; This program allows modifying the WFG input parameters "on the fly"
; on the MC demo board. This allows you to see what is really going on.
;
; First, set up the variables that you want to control:
;
rseg at 40h
;
mode:
op0:
op1:
sync:
pe7:
pe6:
p7:
p6:
ph1:
ph2:
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
;mode = 0-3
;P6.0,2,4 polarity--0=low, 1=high
;P6.1,3,5 polarity--0=low, 1=high
;0=load now, 1 = synchronized
;P6.7 0=i/o, 1=PWM
;P6.6 0=i/o, 1=PWM
;P6.7 I/O value
;P6.7 I/O value
;P6.0,1 config
;P6.2,3 config
9-21
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ph3:
eo:
dp:
it:
es:
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
dsw 1
;P6.4,5 config
;0=disable output, 1=enable output
;0=enable protection, 1=disable
;0=falling edge trig, 1=rising edge
;0=edge, 1=sample
;0=stop cntr, 1=start
;10-bit dead time
ec:
dead:
reload:
comp1:
comp2:
comp3:
temp:
temp1:
temp2:
;
;
;**************************************************
; first, initialize the values for these variables:
;**************************************************
;
cseg at 0e000h
;demo board RAM
;
di
dpts
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
ld
;
sp,#200h
mode,#0000h
ec,#0001h
;mode0
;enable cntr
;1.6 us
;active high
dead,#0010h
op0,#0001h
op1,#0001h
sync,#0001h
pe7,#00000h
pe6,#00000h
p7,#00000h
p6,#00000h
ph1,#0007h
ph2,#0007h
ph3,#0007h
eo,#0001h
dp,#0001h
it,#0001h
es,#0001h
reload,#1000h
comp1,#0100h
comp2,#0200h
comp3,#0400h
;active high
;synchronized WG_OUTPUT load
;P6.7 in I/O mode
;P6.6 in I/O mode
;P6.7 I/O = 0
;P6.6 I/O = 0
;wfg both outputs
;wfg both outputs
;wfg both outputs
;enable outputs
;disable protection
;rising/high edge trigger
;24-state trigger
;1.024 ms mode0
;64 us
;128 us
;256 us
;************************
; now initialize the WFG
;************************
;
;set up interrupts
;
ldb temp,#00010000b
;
stb temp,PI_MASK[0]
ldb temp,#00100000b
ldb int_mask1,temp
;unmask WG interrupt
;
;
;
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WAVEFORM GENERATOR
;load WFG registers
;
call wgout
call loadregs
call protect
;initialize WG_OUTPUT register
;initialize reload & compare regs
;initialize protection
call wgcon
;initialize WG_CONTROL
;
;enable interrupts & loop here
;
ei
sjmp $
;
;****************************************
; form WG_OUTPUT value from variable data
;****************************************
;
wgout:
ld
temp,op1
;get op1
;mask
;move bit to correct location
and temp,#0001h
shl temp,#15
ld
temp1,op0
;get op0
;mask
;move bit to correct location
;combine
and temp1,#0001h
shl temp1,#14
or
temp1,temp
ld
temp,sync
;get sync bit
;mask
;move to correct location
;combine
and temp,#0001h
shl temp,#13
or
temp1,temp
ld
temp,pe7
;get pe7 bit
;mask
;move to correct location
;combine
and temp,#0001h
shl temp,#12
or
temp1,temp
ld
temp,pe6
;get pe6 bit
;mask
;move to correct location
;combine
and temp,#0001h
shl temp,#11
or
temp1,temp
ld
temp,ph3
;get ph3 bits
;mask for ph3.2
;move
and temp,#0004h
shl temp,#8h
or
temp1,temp
;combine
ld
temp,ph2
;get ph2 bits
;mask for ph2.2
;move
and temp,#0004h
shl temp,#7h
or
temp1,temp
;combine
ld
temp,ph1
;get ph1 bits
;mask for ph1.2
;move
and temp,#0004h
shl temp,#6h
or
temp1,temp
;combine
ld
temp,p7
;get p7 bit
and temp,#0001h
shl temp,#7
;mask
;move to correct location
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or
ld
temp1,temp
temp,p6
;combine
;get p6 bit
;mask
;move to correct location
;combine
and temp,#0001h
shl temp,#6
or
temp1,temp
ld
temp,ph3
;get ph3 bits again
;mask for ph3.0 & 1
;move
and temp,#0003h
shl temp,#4h
or
temp1,temp
;combine1
ld
temp,ph2
;get ph2 bits again
;mask for ph2.0 & 1
;move
and temp,#0003h
shl temp,#2h
or
temp1,temp
;combine
ld
temp,ph1
;get ph1 bits again
and temp,#0003h
;mask for ph3.0 & 1
;combine, don't need to move
or
temp1,temp
st
temp1,WG_OUTPUT[0] ;now store it
ret
;
;****************************************
; form WG_CONTROL value
;****************************************
;
wgcon:
ld
temp,mode
;get mode
;mask
;shift to correct location
and temp,#0003h
shl temp,#12
ld
temp1,ec
;start/stop bit
;mask
;shift to correct location
;combine into temp
and temp1,#0001h
shl temp1,#10
or
temp,temp1
ld
temp1,dead
;get dead time
and temp1,#03ffh
;mask to 10 bits
;combine into temp
or
temp,temp1
st
temp,WG_CONTROL[0] ;store WG_CONTROL
ret
;
;*****************************************
;load the WG_RELOAD and WG_COMPx registers
;*****************************************
;
loadregs: st
reload,WG_RELOAD[0]
comp1,WG_COMP1[0]
comp2,WG_COMP2[0]
comp3,WG_COMP3[0]
st
st
st
ret
;
;*************************
;load WG_PROTECT options
;*************************
;
protect:ldtemp,es
;get sample control bit
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WAVEFORM GENERATOR
and temp,#0001h
shl temp,#3
;mask
;shift to correct location
ld
temp1,it
;interrupt type bit
;mask
;shift to correct location
;combine into temp
and temp1,#0001h
shl temp1,#2
or
temp,temp1
ld
temp1,dp
;disable protection bit
;mask
;shift to correct location
;combine into temp
and temp1,#0001h
shl temp1,#1
or
temp,temp1
ld
temp1,eo
;enable output bit
;mask
;combine into temp
and temp1,#0001h
or temp,temp1
stb temp,WG_PROTECT[0];store byte into WG_PROTECT
ret
;
;*******************************************
;interrupt routine for WFG
;*******************************************
;
cseg at 0f1a0h
;demo board PI interrupt
pusha
call wgout
call loadregs
call protect
call wgcon
popa
;update WG_OUTPUT register
;update reload & compare regs
;update protection options
;update WG_CONTROL
ret
end
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10
Pulse-width
Modulator
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CHAPTER 10
PULSE-WIDTH MODULATOR
The pulse-width modulator (PWM) module has two output pins, each of which can output a
PWM signal with a fixed, programmable frequency and a variable duty cycle. These outputs can
be used to drive motors that require an unfiltered PWM waveform for optimal efficiency, or they
can be filtered to produce a smooth analog signal.
This chapter provides a functional overview of the pulse-width modulator module, describes how
to program it, and provides sample circuitry for converting the PWM outputs to analog signals.
For detailed descriptions of the signals and registers discussed in this chapter, please refer to Ap-
pendix B, “Signal Descriptions” and Appendix C, “Registers.”
10.1 PWM FUNCTIONAL OVERVIEW
The PWM module has two channels, each of which consists of a control register
(PWMx_CONTROL), a buffer, a comparator, an RS flip-flop, and an output pin. Two other com-
ponents, an eight-bit counter (PWM_COUNT) and a period register (PWM_PERIOD), are
shared across the PWM module’s two channels, completing the circuitry (see Figure 10-1).
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8
PWMx_CONTROL
Load
Buffer
8
Bufferx
8
=
Comparatorx
8
RS Flip-flopx
Port 6
Control
R
WG_OUT
Q
Internal
Clock
Signal
Down Counter
PWM_COUNT
PWMx
Output
P6.x/PWMx
S
Count
= 00H
8
8
PWM_PERIOD
Load
Shared Circuitry
A2761-02
Figure 10-1. PWM Block Diagram
10.2 PWM SIGNALS AND REGISTERS
Table 10-1 describes the PWM’s signals and Table 10-2 briefly describes the control and status
registers.
Table 10-1. PWM Signals
PWM
Signal
PWM
Signal Type
Port Pin
Description
P6.6
P6.7
PWM0
PWM1
O
O
Pulse-width modulator 0 output with high-drive capability.
Pulse-width modulator 1 output with high-drive capability.
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PULSE-WIDTH MODULATOR
Table 10-2. PWM Control and Status Registers
Address Description
Mnemonic
PWM0_CONTROL 1FB0H
PWM1_CONTROL 1FB2H
PWM Duty Cycle
This register controls the PWM duty cycle. A zero loaded
into this register will cause the PWM to output a low
continuously (0% duty cycle). An FFH in this register will
cause the PWM to have its maximum duty cycle (99.6%
duty cycle).
PWM_PERIOD
1FB4H
PWM Period
This register holds a programmed value that determines
the output period of the PWM outputs. The value is
reloaded into the counter each time the count resets to
FFH.
PWM_COUNT
WG_OUTPUT
1FB6H
1FC0H
PWM Counter
This read-only register contains the current value of the
decremented counter.
Waveform Generator Output
Bits 11 and 12 (PE6 and PE7) determine whether the
corresponding pin functions as a standard I/O port pin or
as a PWM output. Bits 6 and 7 (P6 and P7) define the pin
output when the port pin function is selected.
PEx Px
Pin Output
0
0
1
0
1
X
0
1
PWM Output
10.3 PWM OPERATION
The period register (PWM_PERIOD) controls the output frequency of both PWM outputs. Each
control register (PWMx_CONTROL) controls the duty cycle (the pulsewidth stated as a percent-
age of the period) of the corresponding PWM output. Each control register contains an 8-bit value
that is loaded into a buffer when the 8-bit counter rolls over from 00H to FFH. The comparators
compare the contents of the buffers to the counter value. Since the value written to the control
register is buffered, you can write a new 8-bit value to PWMx_CONTROL at any time. However,
the comparators do not recognize the new value until the counter has expired the remainder of
the current 8-bit count. The new value is used during the next PWM output period.
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The counter counts down to 00H, at which time the PWM output is driven high, the counter value
is reloaded from the PWM_PERIOD register, and the contents of the control registers are loaded
into the buffers. The PWM output remains high until the counter value matches the value in the
buffer, at which time the output is pulled low. You can read the count register (PWM_COUNT)
to see the current value of the counter. When the counter resets again (i.e., when an overflow oc-
curs) the output is switched high. (Loading PWMx_CONTROL with 00H forces the output to re-
main low.) Figure 10-2 shows typical PWM output waveforms.
NOTE
The PWMx_CONTROL register value and corresponding duty cycle result, in
Figure 10-2, are true only when the PWM_PERIOD register value is FFH.
Duty
PWM Control
Output Waveform
Cycle Register Value
0%
10%
50%
90%
99.6%
00H
19H
80H
E6H
FFH
0
0
0
0
0
A0119-02
Figure 10-2. PWM Output Waveforms
10.4 PROGRAMMING THE FREQUENCY AND PERIOD
The input frequency on XTAL1 (FXTAL1) and the contents of the PWM_PERIOD register deter-
mine the PWM output frequency (FPWM) and period (TPWM). Table 10-3 shows the PWM output
frequencies for common values of FXTAL1 with a variety of PWM_PERIOD values. Use the fol-
lowing formulas to calculate the PWM period value for the desired output frequency and write
the corresponding value to the PWM_PERIOD register.
512 × (PWM_PERIOD + 1)
---------------------------------------------------------------------------
TPWM (in µs)
=
FXTAL1
F XTAL1
---------------------------------------------------------------------------
FPWM (in MHz) =
512 × (PWM_PERIOD + 1)
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PULSE-WIDTH MODULATOR
where:
PWM_PERIOD
=
=
=
=
8-bit value to load into the PWM_PERIOD register
input frequency on XTAL1 pin, in MHz
FXTAL
1
TPWM
FPWM
output period on the PWM output pins, in µs
output frequency on the PWM output pins, in MHz
Table 10-3. PWM Output Frequencies (FPWM
)
XTAL1 Frequency (FXTAL
)
1
PWM_PERIOD
8 MHz
10 MHz
16 MHz
00H
0FH
1FH
2FH
3FH
4FH
5FH
6FH
7FH
8FH
9FH
AFH
BFH
CFH
DFH
EFH
FFH
15.6 kHz
976.6 Hz
488.3 Hz
325.5 Hz
244.1 Hz
195.3 Hz
162.8 Hz
139.5 Hz
122.1 Hz
108.5 Hz
97.7 Hz
88.8 Hz
81.4 Hz
75.1 Hz
69.7 Hz
65.1 Hz
61.0 Hz
19.5 kHz
1220.7 Hz
610.3 Hz
406.9 Hz
395.2 Hz
244.1 Hz
203.4 Hz
174.4 Hz
152.6 Hz
135.6 Hz
122.1 Hz
111.0 Hz
101.7 Hz
93.9 Hz
31.2 kHz
1953.1 Hz
976.6 Hz
651.0 Hz
488.3 Hz
390.6 Hz
325.5 Hz
279.0 Hz
244.1 Hz
217.0 Hz
195.3 Hz
177.6 Hz
162.8 Hz
150.2 Hz
139.5 Hz
130.2 Hz
122.0 Hz
87.2 Hz
81.4 Hz
76.0 Hz
10-5
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PWM_PERIOD
Address:
Reset State:
1FB4H
00H
The PWM period (PWM_PERIOD) register controls the period of the PWM outputs. It contains a value
that determines the number of state counts necessary for incrementing the PWM counter. The value
of PWM_PERIOD is loaded into the PWM period count register whenever the count equals zero.
7
0
PWM Period
Bit
Number
Function
7:0
PWM Period
This register controls the period of the PWM outputs. The value of PWM_PERIOD is
loaded into the PWM period count register whenever the count equals zero.
Figure 10-3. PWM Period (PWM_PERIOD) Register
10.5 PROGRAMMING THE DUTY CYCLE
The values written to the PWMx_CONTROL and PWM_PERIOD registers control the width of
the high pulse, effectively controlling the duty cycle. The 8-bit value written to the control regis-
ter is loaded into a buffer, and this value is used during the next period. Use the following duty
cycle formula to calculate a desired duty cycle for given values of PWMx_CONTROL and
PWM_PERIOD, and then write these values to the appropriate registers.
PWMx_CONTROL
------------------------------------------------------
Duty Cycle (in %)
=
=
× 100
PWM_PERIOD + 1
Duty Cycle × TPWM
-----------------------------------------------
Pulsewidth (in µs)
100
where:
PWMx_CONTROL
PWM_PERIOD
Pulsewidth
=
=
=
=
8-bit value to load into the PWMx_CONTROL register
8-bit value to load into the PWM_PERIOD register
width of each high pulse
TPWM
output period on the PWM pin, in µs
10-6
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PULSE-WIDTH MODULATOR
Address:
Reset State:
Table 10-2 on page
PWMx_CONTROL
x = 0–1
10-3
00H
The PWM control (PWMx_CONTROL) register determines the duty cycle of the PWM x channel. A
zero loaded into this register causes the PWM to output a low continuously (0% duty cycle). An FFH in
this register causes the PWM to have its maximum duty cycle (99.6% duty cycle).
7
0
PWM Duty Cycle
Bit
Number
Function
7:0
PWM Duty Cycle
This register controls the PWM duty cycle. A zero loaded into this register causes the
PWM to output a low continuously (0% duty cycle). An FFH in this register causes the
PWM to have its maximum duty cycle (99.6% duty cycle).
Figure 10-4. PWM Control (PWMx_CONTROL) Register
10.5.1 Sample Calculations
For example, assume that FXTAL1 equals 16 MHz and the value written to the PWM_PERIOD reg-
ister is FFH, thus the desired period of the PWM output waveform is 8.19 ms. If
PWMx_CONTROL equals 8AH (138 decimal), the pulsewidth is held high for 4.42 ms (and low
for 3.77 ms) of the total 8.19 ms period, resulting in a duty cycle of approximately 54%.
10.5.2 Reading the Current Value of the Down-counter
You can read the PWM_COUNT register to find the current value of the down-counter (see Fig-
ure 10-5).
10-7
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Address:
Reset State:
1FB6H
00H
PWM_COUNT
(read only)
The PWM count (PWM_COUNT) register provides the current value of the decremented period
counter.
7
0
PWM Count Value
Bit
Number
Function
7:0
PWM Count Value
This register contains the current value of the decremented period counter.
Figure 10-5. PWM Count (PWM_COUNT) Register
10.5.3 Enabling the PWM Outputs
Each PWM output is multiplexed with a port pin, so you must configure it as a special-function
output signal before using the PWM function. To determine whether the corresponding pin func-
tions as a standard I/O port pin or as a PWM output you must make the proper selections by writ-
ing to the WG_OUTPUT register (see Figure 10-6). Table 10-4 shows the alternate port function
along with the register setting that selects the PWM output instead of the port function.
Table 10-4. PWM Output Alternate Functions
PWM Output
Alternate Port Function
PWM Output Enabled When
PWM0
PWM1
P6.6
P6.7
WG_OUT.11 = 1
WG_OUT.12 = 1
10-8
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PULSE-WIDTH MODULATOR
Address:
Reset State:
1FC0H
0000H
WG_OUTPUT (Waveform Generator)
The waveform generator output configuration (WG_OUTPUT) register controls the configuration of
the waveform generator and PWM module pins. Both the waveform generator and the PWM module
share pins with port 6. Having these control bits in a single register enables you to configure all port 6
pins with a single write to WG_OUTPUT.
15
8
OP1
P7
OP0
P6
SYNC
PH3.1
PE7
PE6
PH3.2
PH2.0
PH2.2
PH1.1
PH1.2
PH1.0
7
0
PH3.0
PH2.1
Bit
Number
Bit
Mnemonic
Function
15
OP1
Output Polarity
Output Polarity
Synchronize
14
13
12
OP0
SYNC
PE7
P6.7/PWM1 Function
Selects either the port function or the PWM output function of
P6.7/PWM1.
1 = PWM1
0 = P6.7
11
PE6
P6.6/PWM0 Function
Selects either the port function or the PWM output function of
P6.6/PWM0.
1 = PWM0
0 = P6.6
10
9
PH3.2
PH2.2
PH1.2
P7
Phase 3 Function
Phase 2 Function
Phase 1 Function
8
7
P6.7/PWM1 Value
Write the desired P6.7/PWM1 value to this bit.
6
P6
P6.6/PWM0 Value
Write the desired P6.6/PWM0 value to this bit.
5:4
3:2
1:0
PH3.1:0
PH2.1:0
PH1.1:0
P6.4/WG3# P6.5/WG3 Value
P6.2/WG2#, P6.3/WG2 Values
P6.0/WG1#, P6.1/WG1 Values
Figure 10-6. Waveform Generator Output Configuration (WG_OUTPUT) Register
10-9
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10.5.4 Generating Analog Outputs
PWM modules can generate a rectangular pulse train that varies in duty cycle and period. Filter-
ing this output will create a smooth analog signal. To make a signal swing over the desired analog
range, first buffer the signal and then filter it with either a simple RC network or an active filter.
Figure 10-7 is a block diagram of the type of circuit needed to create the smooth analog signal.
®
MCS 96
Buffer
to Make
Output Swing
Rail
Filter
(Passive
or
Power
Amp
Microcontroller
Analog
Output
PWM
Active)
(Optional)
to
Rail
(Optional)
A2391-01
Figure 10-7. D/A Buffer Block Diagram
Figure 10-8 shows a sample circuit used for low output currents (less than 100 µA). Consider
temperature and power-supply drift when selecting components for the external D/A circuitry.
With proper components, a highly accurate 8-bit D/A converter can be made using the PWM.
PWM
-
R
Analog
Output
+
®
MCS 96
Op Amp
74ACxxx
Buffer
C
Microcontroller
Consider both ripple and response time requirements when selecting R and C.
A2390-02
Figure 10-8. PWM to Analog Conversion Circuitry
10-10
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11
Event Processor
Array (EPA)
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CHAPTER 11
EVENT PROCESSOR ARRAY (EPA)
Control applications often require high-speed event control. For example, the controller may need
to periodically generate pulse-width modulated outputs or an interrupt. In another application, the
controller may monitor an input signal to determine the status of an external device. The event
processor array (EPA) was designed to reduce the CPU overhead associated with these types of
event control. This chapter describes the EPA and its timers and explains how to configure and
program them.
11.1 EPA FUNCTIONAL OVERVIEW
The EPA performs input and output functions associated with two timer/counters, timer 1 and
timer 2 (Figure 11-1). In the input mode, the EPA monitors an input pin for an event: a rising edge,
a falling edge, or an edge in either direction. When the event occurs, the EPA records the value
of the timer/counter, so that the event is tagged with a time. This is called an input capture. Input
captures are buffered to allow two captures before an overrun occurs.
In the output mode, the EPA monitors a timer/counter and compares its value with a value stored
in a register. When the timer/counter value matches the stored value, the EPA can trigger an event:
a timer reset, an A/D conversion, a waveform generator reload, or an output event (set a pin, clear
a pin, toggle a pin, or take no action). This is called an output compare.
Each input capture or an output compare sets an interrupt pending bit. This bit can optionally
cause an interrupt. Table 11-1 lists the capture/compare and compare-only channels for each de-
vice in the 8XC196Mx family.
Table 11-1. EPA Channels
Device
Capture/Compare Channels
Compare-only Channels
8XC196MC
8XC196MD
8XC196MH
EPA3:0
EPA5:0
EPA1:0
COMP3:0
COMP5:0
COMP3:0
11-1
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Timer-counter Unit
TIMER1
TIMER2
Capture/Compare
EPA0 Interrupt
Channel 0
EPA0
EPAx
.
.
.
Capture/Compare
Channel x
EPAx Interrupt
COMP0 Interrupt
Compare-only
Channel 0
COMP0
COMPy
.
.
.
COMPy Interrupt
Compare-only
Channel y
Notes:
For the 8XC196MC, x & y = 3.
For the 8XC196MD, x & y = 5.
For the 8XC196MH, x = 1 & y = 3.
A2846-01
Figure 11-1. EPA Block Diagram
11.2 EPA AND TIMER/COUNTER SIGNALS AND REGISTERS
Table 11-2 describes the EPA and timer/counter input and output signals. Each signal is multi-
plexed with a port pin as shown in the first column. Table 11-3 briefly describes the registers for
the EPA capture/compare channels, EPA compare-only channels, and timer/counters.
Table 11-2. EPA and Timer/Counter Signals
Port Pin
EPA
Signal
Type
EPA
Signals
Description
8XC196MC 8XC196MD 8XC196MH
P1.2
P1.3
P1.2
P1.3
P0.6
P0.7
T1CLK
T1DIR
I
I
External clock source for timer 1.
External direction control for timer 1.
P2.0
P2.1
P2.2
P2.3
—
P2.0
P2.1
P2.2
P2.3
P7.0
P7.1
P2.0
P2.2
—
—
—
EPA0
EPA1
EPA2
EPA3
EPA4
EPA5
I/O
High-speed input/output for the
capture/compare channels.
—
—
11-2
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EVENT PROCESSOR ARRAY (EPA)
Table 11-2. EPA and Timer/Counter Signals (Continued)
Port Pin
EPA
Signal
Type
EPA
Signals
Description
8XC196MC 8XC196MD 8XC196MH
P2.4
P2.5
P2.6
P2.7
—
P2.4
P2.5
P2.6
P2.7
P7.2
P7.3
P2.4
P2.5
P2.6
P2.3
—
COMP0
COMP1
COMP2
COMP3
COMP4
COMP5
O
Output of the compare-only channels.
—
—
Table 11-3. EPA Control and Status Registers
Address
Mnemonic
Description
MC
MD
MH
COMP0_CON
COMP1_CON
COMP2_CON
COMP3_CON
COMP4_CON
COMP5_CON
1F58H
1F5CH
1F60H
1F64H
—
1F58H
1F5CH
1F60H
1F64H
1F68H
1F6CH
1F58H
1F5CH
1F60H
1F4CH
—
EPAx Compare Control
These registers control the functions of the
compare-only channels.
—
—
COMP0_TIME
COMP1_TIME
COMP2_TIME
COMP3_TIME
COMP4_TIME
COMP5_TIME
1F5AH
1F5EH
1F62H
1F66H
—
1F5AH
1F5EH
1F62H
1F66H
1F6AH
1F6EH
1F5AH EPAx Compare Time
1F5EH
These registers contain the time at which an event
1F62H
1F4EH
—
is to occur on the compare-only channels.
—
—
EPA0_CON
EPA1_CON
EPA2_CON
EPA3_CON
EPA4_CON
EPA5_CON
1F40H
1F44H
1F48H
1F4CH
—
1F40H
1F44H
1F48H
1F4CH
1F50H
1F54H
1F40H
1F44H
—
—
—
EPAx Capture/Compare Control
These registers control the functions of the
capture/compare channels. EPA1_CON and
EPA3_CON require an extra byte because they
contain an additional bit for PWM remap mode.
These two registers must be addressed as words;
the others can be addressed as bytes.
—
—
EPA0_TIME
EPA1_TIME
EPA2_TIME
EPA3_TIME
EPA4_TIME
EPA5_TIME
1F42H
1F46H
1F4AH
1F4EH
—
1F42H
1F46H
1F4AH
1F4EH
1F52H
1F56H
1F42H
1F46H
—
—
—
EPAx Capture/Compare Time
In capture mode, these registers contain the
captured timer value. In compare mode, these
registers contain the time at which an event is to
occur. In capture mode, these registers are
buffered to allow two captures before an overrun
occurs. However, they are not buffered in compare
mode.
—
—
INT_MASK
0008H
0013H
0008H
0013H
0008H
0013H
Interrupt Mask
The bits in this 8-bit register enable and disable
(mask) the interrupts associated with the corre-
sponding bits in the INT_PEND register.
INT_MASK1
Interrupt Mask 1
The bits in this 8-bit register enable and disable
(mask) the interrupts associated with the corre-
sponding bits in the INT_PEND1 register.
11-3
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Table 11-3. EPA Control and Status Registers (Continued)
Address
Mnemonic
INT_PEND
Description
MC
MD
MH
0009H
0009H
0009H
Interrupt Pending
Any set bit in this 8-bit register indicates a pending
interrupt request.
INT_PEND1
0012H
0012H
0012H
Interrupt Pending 1
Any set bit in this 8-bit register indicates a pending
interrupt request.
P2_DIR
P7_DIR
1FD2H
—
1FD2H
1FD3H
1FD2H Port x Direction
—
Each bit of Px_DIR controls the direction of the
corresponding pin. Clearing a bit configures a pin
as a complementary output; setting a bit
configures a pin as an input or open-drain output.
(Open-drain outputs require external pull-ups.)
P2_MODE
P7_MODE
1FD0H
—
1FD0H
1FD1H
1FD0H Port x Mode
—
Each bit of Px_MODE controls whether the corre-
sponding pin functions as a standard I/O port pin
or as a special-function signal. Setting a bit
configures a pin as a special-function signal;
clearing a bit configures a pin as a standard I/O
port pin.
P0_PIN
P1_PIN
P2_PIN
P7_PIN
1FA8H
1FA9H
1FD6H
—
1FA8H
1FA9H
1FD6H
1FD7H
1FDAH Port x Input
1F9FH
Each bit of Px_PIN reflects the current state of the
1FD6H
—
corresponding pin, regardless of the pin configu-
ration.
P2_REG
P7_REG
1FD4H
—
1FD4H
1FD5H
1FD4H Port x Data Output
—
For an input, set the corresponding Px_REG bit.
For an output, write the data to be driven out by
each pin to the corresponding bit of Px_REG.
When a pin is configured as standard I/O
(Px_MODE.y = 0), the result of a CPU write to
Px_REG is immediately visible on the pin. When a
pin is configured as a special-function signal
(Px_MODE.y = 1), the associated on-chip
peripheral or off-chip component controls the pin.
The CPU can still write to Px_REG, but the pin is
unaffected until it is switched back to its standard
I/O function.
This feature allows software to configure a pin as
standard I/O (clear Px_MODE.y), initialize or
overwrite the pin value, then configure the pin as a
special-function signal (set Px_MODE.y). In this
way, initialization, fault recovery, exception
handling, etc., can be done without changing the
operation of the associated peripheral.
11-4
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EVENT PROCESSOR ARRAY (EPA)
Table 11-3. EPA Control and Status Registers (Continued)
Address
Mnemonic
PI_MASK
Description
MC
MD
MH
1FBCH Peripheral Interrupt Mask
The bits in this register enable and disable (mask)
1FBCH
1FBCH
the timer 1 and 2 overflow/underflow interrupt
requests, the waveform generator interrupt request
(MC, MD), the EPA compare-only channel 5
interrupt request ( MD), and the serial port error
interrupts (MH).
PI_PEND
1FBEH
1F78H
1FBEH
1F78H
1FBEH Peripheral Interrupt Pending
Any bit set indicates a pending interrupt request.
Timer 1 Control
T1CONTROL
1F78H
This register enables/disables timer 1, controls
whether it counts up or down, selects the clock
source and direction, and determines the clock
prescaler setting.
T1RELOAD
1F72H
1F7CH
1F72H
1F7CH
1F72H
Timer 1 Reload
This register contains an initialization value for
timer 1. A timer 1 overflow or underflows loads the
T1RELOAD value into the TIMER1 register if both
quadrature clocking and the reload function are
enabled (T1CONTROL.5:0 = 1).
T2CONTROL
1F7CH Timer 2 Control
This register enables/disables timer 2, controls
whether it counts up or down, selects the clock
source and direction, and determines the clock
prescaler setting.
TIMER1
TIMER2
1F7AH
1F7EH
1F7AH
1F7EH
1F7AH Timer 1 Value
This register contains the current value of timer 1.
1F7EH Timer 2 Value
This register contains the current value of timer 2.
11.3 TIMER/COUNTER FUNCTIONAL OVERVIEW
The EPA has two 16-bit up/down timer/counters, timer 1 and timer 2, which can be clocked in-
ternally or externally. Each is called a timer if it is clocked internally and a counter if it is clocked
externally. Figure 11-2 illustrates the timer/counter structure.
11-5
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T2CONTROL.2:0
3
Timer 2
Prescaler
Module
F
/4
XTAL1
Clock
Overflow/
Underflow
Timer 1 Overflow/Underflow
TIMER2
Direction
T2CONTROL.6
OVRTM
Interrupt
T1CONTROL.2:0
3
Timer 1
F
/4
XTAL1
Prescaler
Module
Clock
T1CLK
Overflow/
Underflow
Quadrature Count
T1RELOAD
TIMER1
Direction
T1DIR
T1CONTROL.6
Quadrature Direction
A3131-01
Figure 11-2. EPA Timer/Counters
The timer/counters can be used as time bases for input captures, output compares, and pro-
grammed interrupts (software timers). When a counter increments from FFFEH to FFFFH or dec-
rements from 0001H to 0000H, the counter-overflow/underflow interrupt pending bit is set. This
bit can optionally cause an interrupt. The clock source, direction-control source, count direction,
and resolution of the input capture or output compare are all programmable (see “Programming
the Timers” on page 11-15). The maximum count rate is one-half the internal clock rate, or
FXTAL1/4 (see “Internal Timing” on page 2-7). This provides a minimum resolution for an input
capture or output compare of 250 ns (at 16 MHz).
4 ×prescaler_divisor
----------------------------------------------------------
resolution
11-6
=
FXTAL1
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EVENT PROCESSOR ARRAY (EPA)
where:
prescaler_divisor
is the clock prescaler divisor from the TxCONTROL registers (see
“Timer 1 Control (T1CONTROL) Register” on page 11-16 and
“Timer 2 Control (T2CONTROL) Register” on page 11-17).
FXTAL1
is the input frequency on XTAL1.
11.3.1 Cascade Mode (Timer 2 Only)
Timer 2 can be used in cascade mode. In this mode, the timer 1 overflow output is used as the
timer 2 clock input. Either the direction control bit of the timer 2 control register or the direction
control assigned to timer 1 controls the count direction. This method, called cascading, can pro-
vide a slow clock for idle mode timeout control or for slow pulse-width modulation (PWM) ap-
plications (see “Generating a Low-speed PWM Output” on page 11-13).
11.3.2 Quadrature Clocking Modes
Timer 1 can be used in two quadrature clocking modes. Both modes use the T1CLK and T1DIR
pins as quadrature inputs, as shown in Figure 11-3. External quadrature-encoded signals (two sig-
nals at the same frequency that differ in phase by 90°) are input, and the timer increments or dec-
rements by one count on each rising edge and each falling edge. Because the T1CLK and T1DIR
inputs are sampled by the internal phase clocks, transitions must be separated by at least two state
times for proper operation. The count is clocked by PH2, which is PH1 delayed by one-half pe-
riod. The sequence of the signal edges and levels controls the count direction. Refer to Figure
11-4 and Table 11-4 for sequencing information.
A typical source of quadrature-encoded signals is a shaft-angle decoder, shown in Figure 11-3.
Its output signals X and Y are input to T1CLK and T1DIR, which in turn output signals
X_internal and Y_internal. These signals are used in Figure 11-4 and Table 11-4 to describe the
direction of the shaft.
In the default quadrature clocking mode, software must reload the TIMER1 register when timer
1 overflows or underflows. In mode 2 (T1CONTROL.2:0 = 1), timer 1 automatically loads the
value from the T1RELOAD register into the TIMER1 register when an overflow or underflow
occurs. Mode 2 is useful for interfacing to an incremental shaft encoder that turns in only one di-
rection. For this application, initialize T1RELOAD with a value that is one less than the encoder’s
resolution. This method allows timer 1 to track the absolute position of the shaft encoder with no
software overhead.
11-7
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Increment
MCS® 96 Microcontroller
Decrement
PH2
PH1
X
Y
T1CLK
T1DIR
D Q
D Q
D Q
D Q
D Q
D Q
X_internal
Y_internal
Optical
Reader
A1550-01
Figure 11-3. Quadrature Mode Interface
Table 11-4. Quadrature Mode Truth Table
State of X_internal
State of Y_internal
(T1DIR)
Count Direction
(T1CLK)
↑
↓
0
1
↓
↑
0
1
0
1
↓
↑
0
1
↑
↓
Increment
Increment
Increment
Increment
Decrement
Decrement
Decrement
Decrement
11-8
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EVENT PROCESSOR ARRAY (EPA)
CLKOUT†
PH2
T1CLK
T1DIR
COUNT
x
x + 1
x + 2
x + 3
x + 4
x + 5
x + 6
x + 5
x + 4
x + 3
x + 2
x + 1
† CLKOUT is available on the 8XC196MC and 8XC196MD only.
A1549-01
Figure 11-4. Quadrature Mode Timing and Count
11.4 EPA CHANNEL FUNCTIONAL OVERVIEW
The EPA has both programmable capture/compare and compare-only channels. Each cap-
ture/compare channel can perform the following tasks. (The compare-only channels have the
same functionality except that they cannot capture an external event.)
• capture the current timer value when a specified transition occurs on the EPA pin
• start an A/D conversion or reload the waveform generator when an event is captured or the
timer value matches the programmed value in the event-time register
• clear, set, or toggle the EPA pin when the timer value matches the programmed value in the
event-time register
• generate an interrupt when a capture or compare event occurs
• reset its own base timer in compare mode
• reset the opposite timer in both compare and capture mode
11-9
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Each EPA channel has a control register, EPAx_CON (capture/compare channels) or
COMPx_CON (compare-only channels); an event-time register, EPAx_TIME (capture/compare
channels) or COMPx_TIME (compare-only channels); and a timer input (Figure 11-5). The con-
trol register selects the timer, the mode, and either the event to be captured or the event that is to
occur. The event-time register holds the captured timer value in capture mode and the event time
in compare mode. See “Programming the Capture/Compare Channels” on page 11-18 and “Pro-
gramming the Compare-only Channels” on page 11-22 for configuration information.
Timer/Counter Unit
External clocking (T1CLK) with up to 6-bit prescaler
TIMER1
TIMER2
Internal clocking
with up to 6-bit prescaler
Quadrature clocking through T1CLK and T1DIR
Clock on TIMER1 overflow
EPA Capture/Compare
Channel x
Capture
Buffer
EPA Pin
EPAx_TIME
Compare
TGL
Reset Timer
Reload Waveform
EPA
Interrupt
†
Generator
Overwrite
Mode Control
EPAx_CON
††
Start A/D
Mode Selection
†
††
EPA0, EPA2, and EPA4.
EPA1, EPA3, and EPA5
A0807-01
Figure 11-5. A Single EPA Capture/Compare Channel
11.4.1 Operating in Capture Mode
In capture mode, when a valid event occurs on the pin, the value of the selected timer is captured
into a buffer. The timer value is then transferred from the buffer to the EPAx_TIME register,
which sets the EPA interrupt pending bit as shown in Figure 11-6. If enabled, an interrupt is gen-
erated. If a second event occurs before the CPU reads the first timer value in EPAx_TIME, the
current timer value is loaded into the buffer and held there. After the CPU reads the EPAx_TIME
register, the contents of the capture buffer are automatically transferred into EPAx_TIME and the
EPA interrupt pending bit is set.
11-10
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EVENT PROCESSOR ARRAY (EPA)
TIMERx
Event Occurs
at EPA Pin
Capture Buffer
EPA
Interrupt
Pending Bit
Set
EPAx_TIME
Read-out Time Value
A2458-02
Figure 11-6. EPA Simplified Input-capture Structure
If a third event occurs before the CPU reads the event-time register, the overwrite bit
(EPAx_CON.0) determines how the EPA will handle the event. If the bit is clear, the EPA ignores
the third event. If the bit is set, the third event time overwrites the second event time in the capture
buffer. Table 11-5 summarizes the possible actions when a valid event occurs.
NOTE
In order for an event to be captured, the signal must be stable for at least two
state times both before and after the transition occurs (Figure 11-7).
Event 1
2 State
Times
2 State
Times
Event 2
2 State
Times
2 State
Times
A3130-01
Figure 11-7. Valid EPA Input Events
11-11
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Table 11-5. Action Taken When a Valid Edge Occurs
Status of
Capture Buffer
& EPAx_TIME
Overwrite Bit
(EPAx_CON.0)
Action Taken When a Valid Edge Occurs
0
empty
Edge is captured and event time is loaded into the capture buffer and
EPAx_TIME register.
0
1
full
New data is ignored — no capture, EPA interrupt, or transfer occurs.
empty
Edge is captured and event time is loaded into the capture buffer and
EPAx_TIME register.
1
full
Old data is overwritten in the capture buffer.
An input capture event does not set the interrupt pending bit until the captured time value actually
moves from the capture buffer into the EPAx_TIME register. If the buffer contains data and the
PTS is used to service the interrupts, then two PTS interrupts occur almost back-to-back (that is,
with one instruction executed between the interrupts).
11.4.1.1
EPA Overruns
Overruns occur when an EPA input transitions at a rate that cannot be handled by the EPA inter-
rupt service routine. If no overrun handling strategy is in place, and if the following three condi-
tions exist, a situation may occur where both the capture buffer and the EPAx_TIME register
contain data, and no EPA interrupt is generated.
• an input signal with a frequency high enough to cause overruns is present on an enabled
EPA pin, and
• the overwrite bit is set (EPAx_CON.0 = 1; old data is overwritten on overrun), and
• the EPAx_TIME register is read at the exact instant that the EPA recognizes the captured
edge as valid.
The input frequency at which this occurs depends on the length of the interrupt service routine as
well as other factors. Unless the interrupt service routine includes a check for overruns, this situ-
ation will remain the same until the device is reset or the EPAx_TIME register is read. The act of
reading EPAx_TIME allows the buffered time value to be moved into EPAx_TIME. This clears
the buffer and allows another event to be captured. Remember that the act of the transferring the
buffer contents to the EPAx_TIME register is what actually sets the EPAx interrupt pending bit
and generates the interrupt.
11-12
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EVENT PROCESSOR ARRAY (EPA)
11.4.1.2
Preventing EPA Overruns
Any one of the following methods can be used to prevent or recover from an EPA overrun situa-
tion.
• Clear EPAx_CON.0
When the overwrite bit (EPAx_CON.0) is zero, the EPA does not consider the captured
edge until the EPAx_TIME register is read and the data in the capture buffer is transferred to
EPAx_TIME. This prevents overruns by ignoring new input capture events when both the
capture buffer and EPAx_TIME contain valid capture times.
• Check for pending EPAx interrupts before exiting an EPAx ISR
Another method for avoiding this situation is to check for pending EPA interrupts before
exiting the EPA interrupt service routine. This is an easy way to detect overruns and addi-
tional interrupts. It can also save loop time by eliminating the latency necessary to service
the pending interrupt. However, this method cannot be used with the peripheral transaction
server (PTS).
11.4.2 Operating in Compare Mode
When the selected timer value matches the event-time value, the action specified in the control
register occurs (i.e., the pin is set, cleared, or toggled, an A/D conversion is initiated, or the wave-
form generator is reloaded). If the re-enable bit (EPAx_CON.3) is set, the action reoccurs on ev-
ery timer match. If the re-enable bit is cleared, the action does not reoccur until a new value is
written to the event-time register. See “Programming the Capture/Compare Channels” on page
11-18 and “Programming the Compare-only Channels” on page 11-22 for configuration informa-
tion.
In compare mode, you can use the EPA to produce a pulse-width modulated (PWM) output. The
following sections describe two possible methods.
11.4.2.1
Generating a Low-speed PWM Output
You can generate a low-speed, pulse-width modulated output with a single EPA channel and a
standard interrupt service routine. Configure the EPA channel as follows: compare mode, toggle
output, and the compare function re-enabled. Select standard interrupt service, enable the EPA
interrupt, and globally enable interrupts with the EI instruction. When the assigned timer/counter
value matches the value in the event-time register, the EPA toggles the output pin and generates
an interrupt. The interrupt service routine loads a new value into EPAx_TIME.
11-13
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The maximum output frequency depends upon the total interrupt latency and the interrupt-service
execution times used by your system. As additional EPA channels and the other functions of the
microcontroller are used, the maximum PWM frequency decreases because the total interrupt la-
tency and interrupt-service execution time increases. To determine the maximum, low-speed
PWM frequency in your system, calculate your system's worst-case interrupt latency and worst-
case interrupt-service execution time, and then add them together. The worst-case interrupt la-
tency is the total latency of all the interrupts (both normal and PTS) used in your system. The
worst-case interrupt-service execution time is the total execution time of all interrupt service rou-
tines and PTS routines.
Assume a system with a single EPA channel, a single enabled interrupt, and the following inter-
rupt service routine.
;If EPA0-x interrupt is generated
EPA0-x_ISR:
PUSHA
LD EPAx_CON, #toggle_command
ADD EPAx_TIME, TIMERx, [next_duty_ptr]; Load next event time
POPA
RET
The worst-case interrupt latency for a single-interrupt system is 56 state times for external stack
usage and 54 state times for internal stack usage (see “Standard Interrupt Latency” on page 5-10).
To determine the execution time for an interrupt service routine, add up the execution time of the
instructions (Table A-9).
The total execution time for the ISR that services the EPA interrupts is 79 state times for external
stack usage or 71 state times for internal stack usage. Therefore, a single capture/compare channel
can be updated every 125 state times assuming internal stack usage (54 + 71). Each PWM period
requires two updates (one setting and one clearing), so the execution time for a PWM period
equals 250 state times. When the input frequency on XTAL1 is 16 MHz, the PWM period is 31.25
µs and the maximum PWM frequency is 32 kHz.
11.4.2.2
Generating the Highest-speed PWM Output
You can generate a highest-speed, pulse-width modulated output with a pair of EPA channels and
a dedicated timer/counter. The first channel toggles the output when the timer value matches
EPAx_TIME, and at some later time, the second channel toggles the output again and resets the
timer/counter. This restarts the cycle. No interrupts are required, resulting in the highest possible
speed. Software must calculate and load the appropriate EPAx_TIME values and load them at the
correct time in the cycle in order to change the frequency or duty cycle.
11-14
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EVENT PROCESSOR ARRAY (EPA)
With this method, the resolution of the EPA (selected by the TxCONTROL registers; see Figure
11-8 on page 11-16 and Figure 11-9 on page 11-17) determines the maximum PWM output fre-
quency. (Resolution is the minimum time required between consecutive captures or compares.)
When the input frequency on XTAL1 is 16 MHz, a 250 ns resolution results in a maximum PWM
of 4 MHz.
11.5 PROGRAMMING THE EPA AND TIMER/COUNTERS
This section discusses configuring the port pins for the EPA and the timer/counters; describes
how to program the timers, the capture/compare channels, and the compare-only channels; and
explains how to enable the EPA interrupts.
11.5.1 Configuring the EPA and Timer/Counter Signals
Before you can use the EPA, you must configure the appropriate port signals to serve as the spe-
cial-function signals for the EPA and, optionally, for the timer/counter clock source and direction
control signals. See “Bidirectional Ports 1 (MH Only), 2, 5, and 7 (MD Only)” on page 6-4 for
information about configuring the ports.
Table 11-2 on page 11-2 lists the signals associated with the EPA and the timer/counters. Signals
that are not being used for an EPA channel or timer/counter can be configured as standard I/O.
11.5.2 Programming the Timers
The control registers for the timers are T1CONTROL (Figure 11-8) and T2CONTROL (Figure
11-9). Write to these registers to configure the timers. Write to the TIMER1 and TIMER2 regis-
ters (see Table 11-3 on page 11-3 for addresses) to load a specific timer value.
11-15
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T1CONTROL
Address:
Reset State:
1F78H
00H
The timer 1 control (T1CONTROL) register determines the clock source, counting direction, and count
rate for timer 1.
7
0
CE
UD
M2
M1
M0
P2
P1
P0
Bit
Number
Bit
Mnemonic
Function
7
CE
Counter Enable
This bit enables or disables the timer. From reset, the timers are
disabled and not free running.
0 = disables timer
1 = enables timer
6
UD
Up/Down
This bit determines the timer counting direction, in selected modes (see
mode bits, M2:0).
0 = count down
1 = count up
5:3
M2:0
EPA Clock Direction Mode Bits
These bits determine the timer clocking source and direction control
source.
M2
M1
M0
Clock Source Direction Source
0
X
0
0
1
†
0
0
1
1
1
0
1
0
1
1
F
XTAL1/4
T1CLK pin†
XTAL1/4
T1CLK pin†
UD bit (T1CONTROL.6)
UD bit (T1CONTROL.6)
T1DIR pin
F
T1DIR pin
quadrature clocking using T1CLK and T1DIR
If an external clock is selected, the timer counts on both the rising
and falling edges of the clock.
2:0
P2:0
EPA Clock Prescaler Bits
These bits determine the clock prescaler value.
P2
P1
P0
Prescaler Divisor
Resolution†
0
0
0
0
1
1
1
1
†
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
divide by 1 (disabled)
divide by 2
divide by 4
divide by 8
divide by 16
divide by 32
divide by 64
enable T1RELOAD
250 ns
500 ns
1 µs
2 µs
4 µs
8 µs
16 µs
—
At 16 MHz. Use the formula on page 11-6 to calculate the resolution
at other frequencies.
Figure 11-8. Timer 1 Control (T1CONTROL) Register
11-16
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EVENT PROCESSOR ARRAY (EPA)
Address:
Reset State:
1F7CH
00H
T2CONTROL
The timer 2 control (T2CONTROL) register determines the clock source, counting direction, and count
rate for timer 2.
7
0
CE
UD
M2
M1
M0
P2
P1
P0
Bit
Number
Bit
Mnemonic
Function
7
CE
Counter Enable
This bit enables or disables the timer. From reset, the timers are
disabled and not free running.
0 = disables timer
1 = enables timer
6
UD
Up/Down
This bit determines the timer counting direction, in selected modes (see
mode bits, M2:0).
0 = count down
1 = count up
5:3
M2:0
EPA Clock Direction Mode Bits
These bits determine the timer clocking source and direction source.
M2
M1
M0
Clock Source
XTAL1/4
reserved
reserved
reserved
timer 1 overflow
timer 1 overflow
reserved
Direction Source
0
X
0
0
1
1
1
0
0
1
1
0
1
1
0
1
0
1
0
0
1
F
UD bit (T2CONTROL.6)
—
—
—
UD bit (T2CONTROL.6)
same as timer 1
—
2:0
P2:0
EPA Clock Prescaler Bits
These bits determine the clock prescaler value.
P2
P1
P0
Prescaler
Resolution†
0
0
0
0
1
1
1
1
†
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
divide by 1 (disabled)
divide by 2
divide by 4
250 ns
500 ns
1 µs
2 µs
4 µs
8 µs
16 µs
—
divide by 8
divide by 16
divide by 32
divide by 64
reserved
Resolution at 16 MHz. Use the formula on page 11-6 to calculate the
resolution at other frequencies.
Figure 11-9. Timer 2 Control (T2CONTROL) Register
11-17
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11.5.3 Programming the Capture/Compare Channels
The EPAx_CON register controls the function of its assigned capture/compare channel. The reg-
isters are identical with the exception of bit 2. For EPA channels 0, 2, and 4, setting this bit enables
an EPA event to cause a waveform generator reload. For EPA channels 1, 3, and 5, setting this bit
enables an EPA event to cause an A/D conversion. To program a compare event, always write to
EPAx_CON (Figure 11-10) first to configure the EPA capture/compare channel, and then load the
event time into EPAx_TIME. To program a capture event, you need only write to EPAx_CON.
Table 11-6 shows the effects of various combinations of EPAx_CON bit settings for channels 1,
3, or 5.
Table 11-6. Example EPA Control Register Settings for Channels 1, 3, or 5
Capture Mode
WGR
TB
CE
MODE
RE
ROT
ON/RT
/AD
Operation
7
X
X
X
X
X
X
X
6
0
0
0
0
0
0
0
5
0
0
1
1
X
1
0
4
0
1
0
1
1
X
1
3
2
1
—
X
X
X
1
0
0
—
—
—
—
—
—
—
–
None
X
X
X
X
X
X
X
Capture on falling edges
X
Capture on rising edges
X
Capture on both edges
X
Capture on falling edge and reset opposite timer
Capture on rising edge and reset opposite timer
X
1
1
X
Start A/D conversion (EPA1, 3, 5) or reload
waveform generator (EPA0, 2, 4) on falling edge
X
0
1
0
—
1
X
X
Start A/D conversion (EPA1, 3, 5) or reload
waveform generator (EPA0, 2, 4) on rising edge
Compare Mode
WGR
/AD
TB
CE
MODE
RE
ROT
ON/RT
0
Operation
7
X
X
X
X
X
X
X
X
6
1
1
1
1
1
1
1
1
5
0
0
0
1
1
X
X
X
4
0
0
1
0
1
X
X
X
3
X
X
X
X
X
X
X
X
2
—
0
1
—
X
X
X
X
0
0
0
None
Generate interrupt only (software timer)
Clear output pin
X
X
X
X
X
1
X
X
X
1
Set output pin
Toggle output pin
Reset reference timer
Reset opposite timer
1
1
X
X
Start A/D conversion (EPA1, 3, 5) or reload
waveform generator (EPA0, 2, 4)
NOTES:
1. — = bit is not used
2. X = bit may be used, but has no effect on the described operation. These bits cause other operations
to occur.
11-18
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EVENT PROCESSOR ARRAY (EPA)
Address:
Reset State:
See Table 11-3 on page 11-3
00H
EPAx_CON
x = 0–1 (8XC196MH)
x = 0–3 (8XC196MC)
x = 0–5 (8XC196MD)
The EPA control (EPAx_CON) registers control the functions of their assigned capture/compare
channels.
7
0
x = 0, 2, 4
x = 1, 3, 5
TB
TB
CE
CE
M1
M1
M0
M0
RE
WGR
AD
ROT
ROT
ON/RT
7
0
RE
ON/RT
Bit
Number
Bit
Mnemonic
Function
7
TB
Time Base Select
Specifies the reference timer.
0 = timer 1 is the reference timer and timer 2 is the opposite timer
1 = timer 2 is the reference timer and timer 1 is the opposite timer
A compare event (reloading the waveform generator; starting an A/D
conversion; clearing, setting, or toggling an output pin; and/or resetting
either timer) occurs when the reference timer matches the time
programmed in the event-time register.
When a capture event (falling edge, rising edge, or an edge change on
the EPAx pin) occurs, the reference timer value is saved in the EPA event-
time register (EPAx_TIME).
6
CE
Compare Enable
Determines whether the EPA channel operates in capture or compare
mode.
0 = capture mode
1 = compare mode
5:4
M1:0
EPA Mode Select
In capture mode, specifies the type of event that triggers an input capture.
In compare mode, specifies the action that the EPA executes when the
reference timer matches the event time.
M1
M0
Capture Mode Event
0
0
1
1
0
1
0
1
no capture
capture on falling edge
capture on rising edge
capture on either edge
M1
M0
Compare Mode Action
0
0
1
1
0
1
0
1
no output
clear output pin
set output pin
toggle output pin
Figure 11-10. EPA Control (EPAx_CON) Registers
11-19
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Address:
Reset State:
See Table 11-3 on page 11-3
00H
EPAx_CON (Continued)
x = 0–1 (8XC196MH)
x = 0–3 (8XC196MC)
x = 0–5 (8XC196MD)
The EPA control (EPAx_CON) registers control the functions of their assigned capture/compare
channels.
7
0
x = 0, 2, 4
x = 1, 3, 5
TB
TB
CE
CE
M1
M1
M0
M0
RE
WGR
AD
ROT
ROT
ON/RT
7
0
RE
ON/RT
Bit
Number
Bit
Mnemonic
Function
3
RE
Re-enable
Re-enable applies to the compare mode only. It allows a compare event
to continue to execute each time the event-time register (EPAx_TIME)
matches the reference timer rather than only upon the first time match.
0 = compare function is disabled after a single event
1 = compare function always enabled
2
WGR
AD
Waveform Generator Reload; A/D Conversion
The function of this bit depends on the EPA channel.
For EPA capture/compare channels 0, 2, 4:
The WGR bit allows you to use the EPA activities to cause the reload
of new values in the waveform generator.
0 = no action
1 = enables waveform generator reload
For EPA capture/compare channels 1, 3, 5:
The AD bit allows you to use the EPA activities to start an A/D
conversion that has been previously set up in the A/D control
registers.
0 = causes no A/D action
1 = starts an A/D conversion on an output compare
Figure 11-10. EPA Control (EPAx_CON) Registers (Continued)
11-20
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EVENT PROCESSOR ARRAY (EPA)
Address:
Reset State:
See Table 11-3 on page 11-3
00H
EPAx_CON (Continued)
x = 0–1 (8XC196MH)
x = 0–3 (8XC196MC)
x = 0–5 (8XC196MD)
The EPA control (EPAx_CON) registers control the functions of their assigned capture/compare
channels.
7
0
x = 0, 2, 4
x = 1, 3, 5
TB
TB
CE
CE
M1
M1
M0
M0
RE
WGR
AD
ROT
ROT
ON/RT
7
0
RE
ON/RT
Bit
Number
Bit
Mnemonic
Function
1
ROT
Reset Opposite Timer
Controls different functions for capture and compare modes.
In Capture Mode:
0 = causes no action
1 = resets the opposite timer
In Compare Mode:
Selects the timer that is to be reset if the RT bit is set.
0 = selects the reference timer for possible reset
1 = selects the opposite timer for possible reset
The TB bit (bit 7) selects which is the reference timer and which is the
opposite timer.
0
ON/RT
Overwrite New/Reset Timer
The ON/RT bit functions as overwrite new in capture mode and reset
timer in compare mode.
In Capture Mode (ON):
An overrun error is generated when an input capture occurs while the
event-time register (EPAx_TIME) and its buffer are both full. When an
overrun occurs, the ON bit determines whether old data is overwritten or
new data is ignored:
0 = ignores new data
1 = overwrites old data in the buffer
In Compare Mode (RT):
0 = disables the reset function
1 = resets the ROT-selected timer
Figure 11-10. EPA Control (EPAx_CON) Registers (Continued)
11-21
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8XC196MC, MD, MH USER’S MANUAL
11.5.4 Programming the Compare-only Channels
To program a compare event, you must first write to the COMPx_CON register (Figure 11-11) to
configure the compare-only channel and then load the event time into COMPx_TIME.
COMPx_CON has the same bits and settings as EPAx_CON. COMPx_TIME is functionally iden-
tical to EPAx_TIME.
See Table 11-3 on
page 11-3
00H
COMPx_CON
x = 0–3 (8XC196MC, MH)
x = 0–5 (8XC196MD)
Address:
Reset State:
The EPA compare control (COMPx_CON) registers determine the function of the EPA compare
channels.
7
0
0
x = 0, 2, 4
TB
TB
CE
CE
M1
M1
M0
M0
RE
RE
WGR
AD
ROT
ROT
RT
RT
7
x = 1, 3, 5
7
TB
Time Base Select
Specifies the reference timer.
0 = timer 1 is the reference timer and timer 2 is the opposite timer
1 = timer 2 is the reference timer and timer 1 is the opposite timer
A compare event (start of an A/D conversion; clearing, setting, or toggling
an output pin; and/or resetting either timer) occurs when the reference
timer matches the time programmed in the event-time register.
6
CE
Compare Enable
This bit enables the compare function.
0 = compare function disabled
1 = compare function enabled
5:4
M1:0
EPA Mode Select
Specifies the type of compare event.
M1
M0
0
0
1
1
0
1
0
1
no output
clear output pin
set output pin
toggle output pin
3
RE
Re-enable
Allows a compare event to continue to execute each time the event-time
register (COMPx_TIME) matches the reference timer rather than only
upon the first time match.
0 = compare function will drive the output only once
1 = compare function always enabled
Figure 11-11. EPA Compare Control (COMPx_CON) Registers
11-22
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EVENT PROCESSOR ARRAY (EPA)
See Table 11-3 on
page 11-3
00H
COMPx_CON (Continued)
x = 0–3 (8XC196MC, MH)
x = 0–5 (8XC196MD)
Address:
Reset State:
The EPA compare control (COMPx_CON) registers determine the function of the EPA compare
channels.
7
0
0
x = 0, 2, 4
TB
TB
CE
CE
M1
M1
M0
M0
RE
RE
WGR
AD
ROT
ROT
RT
RT
7
x = 1, 3, 5
2
WGR
AD
A/D Conversion, Waveform Generator Reload
The function of this bit depends on the EPA channel.
For EPA capture/compare channels 0, 2, 4:
The WGR bit allows you to use the EPA activities to cause the reload of
new values in the waveform generator.
0 = no action
1 = enables waveform generator reload
For EPA capture/compare channels 1, 3, 5:
The AD bit allows you to use the EPA activities to start an A/D
conversion that has been previously set up in the A/D control registers.
0 = causes no A/D action
1 = starts an A/D conversion on an output compare
1
0
ROT
Reset Opposite Timer
Selects the timer that is to be reset if the RT bit is set.
0 = selects the reference timer for possible reset
1 = selects the opposite timer for possible reset
The state of the TB bit determines which timer is the reference timer and
which timer is the opposite timer.
RT
Reset Timer
This bit controls whether the timer selected by the ROT bit will be reset.
1 = resets the timer selected by the ROT bit
0 = disables the reset function
Figure 11-11. EPA Compare Control (COMPx_CON) Registers (Continued)
11.6 ENABLING THE EPA INTERRUPTS
To enable the interrupts, set the corresponding bits in the INT_MASK register (Figure 5-7 on
page 5-15). To enable the individual sources of the multiplexed PI (MC, MD), SPI (MH), and
OVRTM (Mx) interrupts, set the corresponding bits in the PI_MASK register (Figure 5-9 on page
5-17). Chapter 5, “Standard and PTS Interrupts,” discusses the interrupts in greater detail.
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11.7 DETERMINING EVENT STATUS
In compare mode, an interrupt pending bit is set each time a match occurs on an enabled event
(even if the interrupt is specifically masked in the mask register). In capture mode, an interrupt
pending bit is set each time a programmed event is captured and the event time moves from the
capture buffer to the EPAx_TIME register.
The pending bits are located in the INT_PEND and INT_PEND1 registers (Figure 5-7 on page
5-15 and Figure 5-11 on page 5-22). The pending bits for the multiplexed interrupts (those that
share the PI interrupt) are located in the PI_PEND register (Figure 5-12 on page 5-23). Timer
overflows/underflows also set interrupt pending bits. Even if an interrupt is masked, software can
poll the interrupt pending registers to determine whether an event has occurred.
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12
Analog-to-digital
Converter
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CHAPTER 12
ANALOG-TO-DIGITAL (A/D) CONVERTER
The analog-to-digital (A/D) converter can convert an analog input voltage to a digital value and
set the A/D interrupt pending bit when it stores the result. It can also monitor a pin and set the
A/D interrupt pending bit when the input voltage crosses over or under a programmed threshold
voltage. This chapter describes the A/D converter and explains how to program it.
12.1 A/D CONVERTER FUNCTIONAL OVERVIEW
The A/D converter (Figure 12-1) can convert an analog input voltage to an 8- or 10-bit digital
result and set the A/D interrupt pending bit when it stores the result. It can also monitor an input
and set the A/D interrupt pending bit when the input voltage crosses over or under the pro-
grammed threshold voltage.
Analog Inputs
Analog Mux
†
EPA or PTS
Command
VREF
ANGND
Control
Logic
Successive
Sample
and Hold
Approximation
A/D
Converter
Status
AD_RESULT
AD_COMMAND
AD_TIME
AD_TEST
† Multiplexed with port inputs
A2652-02
Figure 12-1. A/D Converter Block Diagram
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12.2 A/D CONVERTER SIGNALS AND REGISTERS
Table 12-1 lists the A/D signals and Table 12-2 describes the control and status registers. Al-
though the analog inputs are multiplexed with I/O port pins, no configuration is necessary.
Table 12-1. A/D Converter Pins
A/D Signal
Port Pin
A/D Signal
Description
Type
P1.4:0
P1.5:0
ACH12:8 (MC)
ACH13:8 (MD)
I
Analog inputs. See the “Voltage on Analog Input Pin”
specification in the datasheet.
P0.7:0
ACH7:0
(MC, MD, MH)
I
Analog inputs. See the “Voltage on Analog Input Pin”
specification in the datasheet.
—
ANGND
VREF
GND
Reference Ground
Must be connected for A/D converter and port operation.
—
PWR
Reference Voltage
Must be connected for A/D converter and port operation.
Table 12-2. A/D Control and Status Registers
Address Description
1FACH
Mnemonic
AD_COMMAND
A/D Command
This register selects the A/D channel, controls whether the A/D
conversion starts immediately or is triggered by the EPA, and
selects the operating mode.
AD_RESULT
1FAAH, 1FABH
A/D Result
For an A/D conversion, the high byte contains the eight MSBs from
the conversion, while the low byte contains the two LSBs from a 10-
bit conversion (undefined for an 8-bit conversion), indicates which
A/D channel was used, and indicates whether the channel is idle.
For a threshold-detection, calculate the value for the successive
approximation register and write that value to the high byte of
AD_RESULT. Clear the low byte or leave it in its default state.
AD_TEST
AD_TIME
1FAEH
1FAFH
A/D Conversion Test
This register specifies adjustments for zero-offset errors.
A/D Conversion Time
This register defines the sample window time and the conversion
time for each bit.
INT_MASK
INT_PEND
0008H
0009H
Interrupt Mask
The AD bit in this register enables or disables the A/D interrupt. Set
the AD bit to enable the interrupt request.
Interrupt Pending
The AD bit in this register, when set, indicates that an A/D interrupt
request is pending.
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ANALOG-TO-DIGITAL (A/D) CONVERTER
Table 12-2. A/D Control and Status Registers (Continued)
Mnemonic
P0_PIN
Address
Description
1FA8H (MC, MD) Port 0 Pin State
1FDAH (MH)
Read P0_PIN to determine the current values of the port 0 pins.
Reading the port induces noise into the A/D converter, decreasing
the accuracy of any conversion in progress. We strongly
recommend that you not read the port while an A/D conversion is in
progress. To reduce noise, the P0_PIN register is clocked only
when the port is read.
P1_PIN (MC,MD) 1FA9H (MC, MD) Port 1 Pin State
Read P1_PIN to determine the current values of the port 1 pins.
Reading the port induces noise into the A/D converter, decreasing
the accuracy of any conversion in progress. We strongly
recommend that you not read the port while an A/D conversion is in
progress. To reduce noise, the P1_PIN register is clocked only
when the port is read.
12.3 A/D CONVERTER OPERATION
An A/D conversion converts an analog input voltage to a digital value, stores the result in the
AD_RESULT register, and sets the A/D interrupt pending bit. An 8-bit conversion provides
20 mV resolution, while a 10-bit conversion provides 5 mV resolution. An 8-bit conversion takes
less time than a 10-bit conversion because it has two fewer bits to resolve and the comparator re-
quires less settling time for 20 mV resolution than for 5 mV resolution.
You can convert either the voltage on an analog input channel or a test voltage. Converting the
test inputs allows you to calculate the zero-offset error, and the zero-offset adjustment allows you
to compensate for it. This feature can reduce or eliminate off-chip compensation hardware. Typ-
ically, you would convert the test voltages and adjust for the zero-offset error before performing
conversions on an input channel. The AD_TEST register allows you to program a zero-offset ad-
justment.
A threshold-detection compares an input voltage to a programmed reference voltage and sets the
A/D interrupt pending bit when the input voltage crosses over or under the reference voltage.
A conversion can be started by a write to the AD_COMMAND register or it can be initiated by
the EPA, which can provide equally spaced samples or synchronization with external events.
(See“Programming the EPA and Timer/Counters” on page 11-15.) The A/D scan mode of the pe-
ripheral transaction server (PTS) allows you to perform multiple conversions and store their re-
sults. (See “A/D Scan Mode” on page 5-32.)
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Once the A/D converter receives the command to start a conversion, a delay time elapses before
sampling begins. (EPA-initiated conversions begin after the capture/compare event. Immediate
conversions, those initiated directly by a write to AD_COMMAND, begin within three state
times after the instruction is completed.) During this sample delay, the hardware clears the suc-
cessive approximation register and selects the designated multiplexer channel. After the sample
delay, the device connects the multiplexer output to the sample capacitor for the specified sample
time. After this sample window closes, it disconnects the multiplexer output from the sample ca-
pacitor so that changes on the input pin will not alter the stored charge while the conversion is in
progress. The device then zeros the comparator and begins the conversion.
The A/D converter uses a successive approximation algorithm to perform the analog-to-digital
conversion. The converter hardware consists of a 256-resistor ladder, a comparator, coupling ca-
pacitors, and a 10-bit successive approximation register (SAR) with logic that guides the process.
The resistive ladder provides 20 mV steps (VREF = 5.12 volts), while capacitive coupling creates
5 mV steps within the 20 mV ladder voltages. Therefore, 1024 internal reference voltage levels
are available for comparison against the analog input to generate a 10-bit conversion result. In 8-
bit conversion mode, only the resistive ladder is used, providing 256 internal reference voltage
levels.
The successive approximation conversion compares a sequence of reference voltages to the ana-
log input, performing a binary search for the reference voltage that most closely matches the in-
put. The ½ full scale reference voltage is the first tested. This corresponds to a 10-bit result where
the most-significant bit is zero and all other bits are ones (0111111111B). If the analog input was
less than the test voltage, bit 10 of the SAR is left at zero, and a new test voltage of ¼ full scale
(0011111111B) is tried. If the analog input was greater than the test voltage, bit 9 of SAR is set.
Bit 8 is then cleared for the next test (0101111111B). This binary search continues until 10 (or 8)
tests have occurred, at which time the valid conversion result resides in the AD_RESULT register
where it can be read by software. The result is equal to the ratio of the input voltage divided by
the analog supply voltage. If the ratio is 1.00, the result will be all ones.
12.4 PROGRAMMING THE A/D CONVERTER
The following A/D converter parameters are programmable:
• conversion input — input channel
• zero-offset adjustment — no adjustment, plus 2.5 mV, minus 2.5 mV, or minus 5.0 mV
• conversion times — sample window time and conversion time for each bit
• operating mode — 8- or 10-bit conversion or 8-bit high or low threshold detection
• conversion trigger — immediate or EPA starts
This section describes the A/D converter’s registers and explains how to program them.
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12.4.1 Programming the A/D Test Register
The AD_TEST register (Figure 12-2) analog specifies an offset voltage to be applied to the resis-
tor ladder. To use the zero-offset adjustment, first perform two conversions, one on ANGND and
one on VREF. With the results of these conversions, use a software routine to calculate the zero-
offset error. Specify the zero-offset adjustment by writing the appropriate value to AD_TEST.
This offset voltage is added to the resistor ladder and applies to all input channels. “Understand-
ing A/D Conversion Errors” on page 12-13 describes zero-offset and other errors inherent in A/D
conversions.
Address:
Reset State (MC, MD):
Reset State (MH):
1FAEH
C0H
AD_TEST
88H
The A/D test (AD_TEST) register specifies adjustments for DC offset errors.
7
0
—
—
—
OFF1
—
OFF0
—
—
Bit
Number
Bit
Mnemonic
Function
7:5
—
Reserved; for compatibility with future devices, write zeros to these bits.
4
OFF1
Offset
This bit , along with OFF0 (bit 2) allows you to set the zero offset point.
OFF1 OFF0
0
0
1
1
0
1
0
1
no adjustment
add 2.5 mV
subtract 2.5 mV
subtract 5.0 mV
3
—
Reserved; for compatibility with future devices, write zero to this bit.
See bit 4 (OFF1).
2
OFF0
—
1:0
Reserved; for compatibility with future devices, write zeros to these bits.
Figure 12-2. A/D Test (AD_TEST) Register
12.4.2 Programming the A/D Result Register (for Threshold Detection Only)
To use the threshold-detection modes, you must first write a value to the high byte of
AD_RESULT to set the desired reference (threshold) voltage.
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AD_RESULT (Write)
Address:
Reset State (MC, MD):
Reset State (MH):
1FAAH
FFC0H
7FC0H
The high byte of the A/D result (AD_RESULT) register can be written to set the reference voltage for
the A/D threshold-detection modes.
15
8
0
REFV7
REFV6
—
REFV5
—
REFV4
—
REFV3
—
REFV2
—
REFV1
—
REFV0
—
7
—
Bit
Number
Bit
Mnemonic
Function
15:8
REFV7:0
Reference Voltage
These bits specify the threshold value. This selects a reference voltage
that is compared with an analog input pin. When the voltage on the
analog input pin crosses over (detect high) or under (detect low) the
threshold value, the A/D conversion complete interrupt pending bit is set.
Use the following formula to determine the value to write to this register
for a given threshold voltage.
desired threshold voltage × 256
----------------------------------------------------------------------------------
reference voltage =
V
REF – ANGND
7:0
—
Figure 12-3. A/D Result (AD_RESULT) Register — Write Format
Reserved; for compatibility with future devices, write zeros to these bits.
12.4.3 Programming the A/D Time Register
Two parameters, sample time and conversion time, control the time required for an A/D conver-
sion. The sample time is the length of time that the analog input voltage is actually connected to
the sample capacitor. If this time is too short, the sample capacitor will not charge completely. If
the sample time is too long, the input voltage may change and cause conversion errors. The con-
version time is the length of time required to convert the analog input voltage stored on the sample
capacitor to a digital value. The conversion time must be long enough for the comparator and cir-
cuitry to settle and resolve the voltage. Excessively long conversion times allow the sample ca-
pacitor to discharge, degrading accuracy.
The AD_TIME register (Figure 12-4) specifies the A/D sample and conversion times. To avoid
erroneous conversion results, use the TSAM and TCONV specifications on the datasheet to determine
appropriate values.
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Address:
Reset State:
1FAFH
FFH
AD_TIME
The A/D time (AD_TIME) register programs the sample window time and the conversion time for each
bit. This register programs the speed at which the A/D can run — not the speed at which it can convert
correctly. Consult the data sheet for recommended values. Initialize the AD_TIME register before
initializing the AD_COMMAND register. Do not write to this register while a conversion is in progress;
the results are unpredictable.
7
0
SAM2
SAM1
SAM0
CONV4
CONV3
CONV2
CONV1
CONV0
Bit
Number
Bit
Mnemonic
Function
7:5
SAM2:0
A/D Sample Time
These bits specify the sample time. Use the following formula to
compute the sample time.
TSAM × FXTAL1 – 2
------------------------------------------------
SAM =
8
where:
SAM
=
=
=
1 to 7
TSAM
FXTAL1
the sample time, in µsec, from the data sheet
the input frequency on XTAL1, in MHz
4:0
CONV4:0
A/D Convert Time
These bits specify the conversion time for each bit. Use the following
formula to compute the conversion time.
TCONV ×FXTAL1 – 3
----------------------------------------------------
CONV =
where:
– 1
2 ×B
CONV= 2 to 31
TCONV
FXTAL1
B
=
=
=
the conversion time, in µsec, from the data sheet
the input frequency on XTAL1, in MHz
the number of bits to be converted (8 or 10)
Figure 12-4. A/D Time (AD_TIME) Register
12.4.4 Programming the A/D Command Register
The A/D command register controls the operating mode, the analog input channel, and the con-
version trigger.
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AD_COMMAND
Address:
Reset State:
1FACH
80H
The A/D command (AD_COMMAND) register selects the A/D channel number to be converted,
controls whether the A/D converter starts immediately or with an EPA command, and selects the
conversion mode.
7
0
—
M1
M0
GO
ACH3
ACH2
ACH1
ACH0
Bit
Number
Bit
Mnemonic
Function
7
—
Reserved; for compatibility with future devices, write zeros to these bits.
6:5
M1:0
A/D Mode†
These bits determine the A/D mode.
M1
M0
Mode
0
0
1
1
0
1
0
1
10-bit conversion
8-bit conversion
threshold detect high
threshold detect low
4
GO
A/D Conversion Trigger††
Writing this bit arms the A/D converter. The value that you write to it
determines at what point a conversion is to start.
0 = EPA initiates conversion
1 = start immediately
3:0
ACH3:0
A/D Channel Selection
Write the A/D conversion channel number to these bits.
†
While a threshold-detection mode is selected for an analog input pin, no other conversion can be
started. If another value is loaded into AD_COMMAND, the threshold-detection mode is disabled
and the new command is executed.
††
It is the act of writing to the GO bit, rather than its value, that starts a conversion. Even if the GO bit
has the desired value, you must set it again to start a conversion immediately or clear it again to
arm it for an EPA-initiated conversion.
Figure 12-5. A/D Command (AD_COMMAND) Register
12.4.5 Enabling the A/D Interrupt
The A/D converter can set the A/D interrupt pending bit when it completes a conversion or when
the input voltage crosses the threshold value in the selected direction. To enable the interrupt, set
the corresponding mask bit in the interrupt mask register (see Table 12-2 on page 12-2) and exe-
cute the EI instruction to globally enable servicing of interrupts. The A/D interrupt can cause the
PTS to begin a new conversion. See Chapter 5, “Standard and PTS Interrupts,” for details about
interrupts and a description of using the PTS in A/D scan mode.
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ANALOG-TO-DIGITAL (A/D) CONVERTER
12.5 DETERMINING A/D STATUS AND CONVERSION RESULTS
You can read the AD_RESULT register (Figure 12-6) to determine the status of the A/D convert-
er. The AD_RESULT register is cleared when a new conversion is started; therefore, to prevent
losing data, you must read both bytes before a new conversion starts. If you read AD_RESULT
before the conversion is complete, the result is not guaranteed to be accurate.
The conversion result is the ratio of the input voltage to the reference voltage:
V
IN – ANGND
V
IN – ANGND
------------------------------------------
------------------------------------------
RESULT (8-bit) = 255 ×
RESULT (10-bit) = 1023 ×
V
REF – ANGND
VREF – ANGND
You can also read the interrupt pending register (see Table 12-2 on page 12-2) to determine the
status of the A/D interrupt.
Address:
Reset State (MC, MD):
Reset State (MH):
1FAAH
FFC0H
7FC0H
AD_RESULT (Read)
The A/D result (AD_RESULT) register consists of two bytes. The high byte contains the eight most-
significant bits from the A/D converter. The low byte contains the two least-significant bits from a ten-
bit A/D conversion, indicates the A/D channel number that was used for the conversion, and indicates
whether a conversion is currently in progress.
15
ADRLT9
8
ADRLT8
ADRLT0
ADRLT7
—
ADRLT6
STATUS
ADRLT5
ACH3
ADRLT4
ACH2
ADRLT3
ACH1
ADRLT2
7
0
ADRLT1
ACH0
Bit
Number
Bit
Mnemonic
Function
15:6
ADRLT9:0
A/D Result
These bits contain the A/D conversion result.
Reserved. This bit is undefined.
A/D Status
5
4
—
STATUS
Indicates the status of the A/D converter. Up to 8 state times are required
to set this bit following a start command. When testing this bit, wait at
least the 8 state times.
0 = A/D is idle
1 = A/D conversion is in progress
3:0
ACH3:0
A/D Channel Number
These bits indicate the A/D channel number that was used for the
conversion.
Figure 12-6. A/D Result (AD_RESULT) Register — Read Format
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12.6 DESIGN CONSIDERATIONS
This section describes considerations for the external interface circuitry and describes the errors
that can occur in any A/D converter. The datasheet lists the absolute error specification, which
includes all deviations between the actual conversion process and an ideal converter. However,
because the various components of error are important in many applications, the datasheet also
lists the specific error components. This section describes those components. For additional in-
®
formation and design techniques, consult AP-406, MCS 96 Analog Acquisition Primer (order
number 270365). Application note AP-406 is also included in the Embedded Microcontrollers
handbook.
12.6.1 Designing External Interface Circuitry
The external interface circuitry to an analog input is highly dependent upon the application and
can affect the converter characteristics. Factors such as input pin leakage, sample capacitor size,
and multiplexer series resistance from the input pin to the sample capacitor must be considered
in the external circuit’s design. These factors are idealized in Figure 12-7.
Sample
External
Internal
RF
~2pF
CS
RSOURCE
~1KΩ
AV
R1
V
ILI1
+
-
Leakage
A0243-02
Figure 12-7. Idealized A/D Sampling Circuitry
During the sample window, the external input circuit must be able to charge the sample capacitor
(CS) through the series combination of the input source resistance (RSOURCE), the input series re-
sistance (R1), and the comparator feedback resistance (RF). The total effective series resistance
(RT) is calculated using the following formula, where AV is the gain of the comparator circuit.
RF
----------------
RT = RSOURCE + R1
+
A
V + 1
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Typically, the (RF / AV + 1) term is the major contributor to the total resistance and the factor that
determines the minimum sample time specified in the datasheet.
12.6.1.1
Minimizing the Effect of High Input Source Resistance
Under some conditions, the input source resistance (RSOURCE) can be great enough to affect the
measurement. You can minimize this effect by increasing the sample time or by connecting an
external capacitor (CEXT) from the input pin to ANGND. The external signal will charge CEXT to
the source voltage level. When the channel is sampled, CEXT acts as a low-impedance source to
charge the sample capacitor (CS). A small portion of the charge in CEXT is transferred to CS, re-
sulting in a drop of the sampled voltage. The voltage drop is calculated using the following for-
mula.
CS
---------------------------
Sampled Voltage Drop, % =
× 100%
C
EXT + CS
If CEXT is 0.005 µF or greater, the error will be less than –0.4 LSB in 10-bit conversion mode. The
use of CEXT in conjunction with RSOURCE forms a low-pass filter that reduces noise input to the
A/D converter.
High RSOURCE resistance can also cause errors due to the input leakage (ILI1). ILI1 is typically much
lower than its specified maximum (consult the datasheet for specifications). The combined effect
of ILI1 leakage and high RSOURCE resistance is calculated using the following formula.
RSOURCE × ILI1 × 1024
-----------------------------------------------------------
error (LSBs) =
VREF
where:
RSOURCE
is the input source resistance, in ohms
is the input leakage, in amperes
is the reference voltage, in volts
ILI
1
VREF
External circuits with RSOURCE resistance of 1 kilo-ohm or lower and VREF equal to 5.0 volts will
have a resultant error due to source impedance of 0.6 LSB or less.
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12.6.1.2
Suggested A/D Input Circuit
The suggested A/D input circuit shown in Figure 12-8 provides limited protection against over-
voltage conditions on the analog input. Should the input voltage be driven significantly below
ANGND or above VREF, diode D2 or D1 will forward bias at about 0.8 volts. The device’s input
protection begins to turn on at approximately 0.5 volts beyond ANGND or VREF. The 270Ω re-
sistor limits the current input to the analog input pin to a safe value, less than 1 mA.
NOTE
Driving any analog input more than 0.5 volts beyond ANGND or VREF begins
to activate the input protection devices. This drives current into the internal
reference circuitry and substantially degrades the accuracy of A/D conversions
on all channels.
VREF
VREF
D1
270Ω
100Ω
ACHx
(Optional)
0.005µF
D2
ANGND
8XC196
Device
ANGND
A0082-03
Figure 12-8. Suggested A/D Input Circuit
Analog Ground and Reference Voltages
12.6.1.3
Reference supply levels strongly influence the absolute accuracy of the conversion. For this rea-
son, we recommend that you tie the ANGND pin to the VSS pin as close to the device as possible,
using a minimum trace length. In a noisy environment, we highly recommend the use of a sepa-
rate analog ground plane that connects to VSS at a single point as close to the device as possible.
IREF may vary between 2 mA and 5 mA during a conversion. To minimize the effect of this fluc-
tuation, mount a 1.0 µF ceramic or tantalum bypass capacitor between VREF and ANGND, as close
to the device as possible.
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ANGND should be within about ± 50 mV of VSS. VREF should be well regulated and used only
for the A/D converter. The VREF supply can be between 4.5 and 5.5 volts and must be able to
source approximately 5 mA (see the datasheet for actual specifications). VREF should be approx-
imately the same voltage as VCC. VREF and VCC should power up at the same time, to avoid poten-
tial latch-up conditions on VREF. Large negative current spikes on the ANGND pin relative to VSS
may cause the analog circuitry to latch up. This is an additional reason to follow careful ground-
ing practice.
The analog reference voltage (VREF) is the positive supply to which all A/D conversions are com-
pared. It is also the supply to port 0 (and port 1 for the MC and MD) if the A/D converter is not
being used. If high accuracy is not required, VREF can be tied to VCC. If accuracy is important,
VREF must be very stable. One way to accomplish this is through the use of a precision power sup-
ply or a separate voltage regulator (usually an IC). These devices must be referenced to ANGND,
not to VSS, to ensure that VREF tracks ANGND and not VSS.
12.6.1.4
Using Mixed Analog and Digital Inputs
Port 0 (and port 1 for the MC and MD) may be used for both analog and digital input signals at
the same time. However, reading the port may inject some noise into the analog circuitry. For this
reason, make certain that an analog conversion is not in progress when the port is read. Refer to
Chapter 6, “I/O Ports,” for information about using the port as digital inputs.
12.6.2 Understanding A/D Conversion Errors
The conversion result is the ratio of the input voltage to the reference voltage.
V
IN – ANGND
V
IN – ANGND
------------------------------------------
------------------------------------------
RESULT (8-bit) = 255 ×
RESULT (10-bit) = 1023 ×
V
REF – ANGND
VREF – ANGND
This ratio produces a stair-stepped transfer function when the output code is plotted versus input
voltage. The resulting digital codes can be taken as simple ratiometric information, or they pro-
vide information about absolute voltages or relative voltage changes on the inputs.
The more demanding the application, the more important it is to fully understand the converter’s
operation. For simple applications, knowing the absolute error of the converter is sufficient.
However, closing a servo-loop with analog inputs requires a detailed understanding of an A/D
converter’s operation and errors.
12-13
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In many applications, it is less critical to record the absolute accuracy of an input than it is to de-
tect that a change has occurred. This approach is acceptable as long as the converter is monotonic
and has no missing codes. That is, increasing input voltages produce adjacent, unique output
codes that are also increasing. Decreasing input voltages produce adjacent, unique output codes
that are also decreasing. In other words, there exists a unique input voltage range for each 10-bit
output code that produces that code only, with a repeatability of typically ± 0.25 LSBs (1.5 mV).
The inherent errors in an analog-to-digital conversion process are quantizing error, zero-offset er-
ror, full-scale error, differential nonlinearity, and nonlinearity. All of these are transfer function
errors related to the A/D converter. In addition, temperature coefficients, VCC rejection, sample-
hold feedthrough, multiplexer off-isolation, channel-to-channel matching, and random noise
should be considered. Fortunately, one absolute error specification (listed in datasheets) de-
scribes the total of all deviations between the actual conversion process and an ideal converter.
However, the various components of error are important in many applications.
An unavoidable error results from the conversion of a continuous voltage to an integer digital rep-
resentation. This error, called quantizing error, is always ± 0.5 LSB. Quantizing error is the only
error seen in a perfect A/D converter, and it is obviously present in actual converters. Figure 12-9
shows the transfer function for an ideal 3-bit A/D converter.
12-14
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ANALOG-TO-DIGITAL (A/D) CONVERTER
7
FINAL CODE TRANSITION OCCURS
WHEN THE APPLIED VOLTAGE IS
EQUAL TO (Vref – 1.5 (LSB)).
6
5
4
3
2
1
0
ACTUAL CHARACTERISTIC OF
AN IDEAL A/D CONVERTER
THE VOLTAGE CHANGE
BETWEEN THE ADJACENT CODE
TRANSITIONS (THE “CODE
WIDTH”) IS = 1 LSB.
FIRST CODE TRANSITION OCCURS
WHEN THE APPLIED VOLTAGE IS
EQUAL TO 1/2 LSB.
1/2
1
2
3
4
5
6
6 1/2
7
8
INPUT VOLTAGE (LSBs)
A0083-01
Figure 12-9. Ideal A/D Conversion Characteristic
Note that the ideal characteristic possesses unique qualities:
• its first code transition occurs when the input voltage is 0.5 LSB;
• its full-scale code transition occurs when the input voltage equals the full-scale reference
voltage minus 1.5 LSB (VREF – 1.5LSB); and
• its code widths are all exactly one LSB.
These qualities result in a digitization without zero-offset, full-scale, or linearity errors; in other
words, a perfect conversion.
12-15
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7
6
FULL SCALE ERROR
IDEAL
CHARACTERISTIC
5
4
3
2
1
0
ACTUAL
CHARACTERISTIC
ABSOLUTE ERROR
ZERO OFFSET
1/2
1
2
3
4
5
6
6 1/2
7
8
INPUT VOLTAGE (LSBs)
A0084-01
Figure 12-10. Actual and Ideal A/D Conversion Characteristics
The actual characteristic of a hypothetical 3-bit converter is not perfect. When the ideal charac-
teristic is overlaid with the actual characteristic, the actual converter is seen to exhibit errors in
the locations of the first and final code transitions and in code widths, as shown in Figure 12-10.
The deviation of the first code transition from ideal is called zero-offset error, and the deviation
of the final code transition from ideal is full-scale error. The deviation of a code width from ideal
causes two types of errors: differential nonlinearity and nonlinearity. Differential nonlinearity is
a measure of local code-width error, whereas nonlinearity is a measure of overall code-transition
error.
12-16
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ANALOG-TO-DIGITAL (A/D) CONVERTER
Differential nonlinearity is the degree to which actual code widths differ from the ideal one-LSB
width. It provides a measure of how much the input voltage may have changed in order to produce
a one-count change in the conversion result. In the 10-bit converter, the code widths are ideally
5 mV (VREF / 1024). If such a converter is specified to have a maximum differential nonlinearity
of 2 LSBs (10 mV), the maximum code width will be no greater than 10 mV larger than ideal, or
15 mV.
Because the A/D converter has no missing codes, the minimum code width will always be greater
than –1 (negative one). The differential nonlinearity error on a particular code width is compen-
sated for by other code widths in the transfer function, such that 1024 unique steps occur. The
actual code widths in this converter typically vary from 2.5 mV to 7.5 mV.
Nonlinearity is the worst-case deviation of code transitions from the corresponding code transi-
tions of the ideal characteristic. Nonlinearity describes the extent to which differential nonlinear-
ities can add up to produce an overall maximum departure from a linear characteristic. If the
differential nonlinearity errors are too large, it is possible for an A/D converter to miss codes or
to exhibit non-monotonic behavior. Neither behavior is desirable in a closed-loop system. A con-
verter has no missing codes if there exists for each output code a unique input voltage range that
produces that code only. A converter is monotonic if every subsequent code change represents an
input voltage change in the same direction.
Differential nonlinearity and nonlinearity are quantified by measuring the terminal-based linear-
ity errors. A terminal-based characteristic results when an actual characteristic is translated and
scaled to eliminate zero-offset and full-scale error, as shown in Figure 12-11. The terminal-based
characteristic is similar to the actual characteristic that would result if zero-offset and full-scale
error were externally trimmed away. In practice, this is done by using input circuits that include
gain and offset trimming. In addition, VREF could also be closely regulated and trimmed within
the specified range to affect full-scale error.
Other factors that affect a real A/D converter system include temperature drift, failure to com-
pletely reject unwanted signals, multiplexer channel dissimilarities, and random noise. Fortunate-
ly, these effects are small. Temperature drift is the rate at which typical specifications change with
a change in temperature. These changes are reflected in the temperature coefficients. Unwanted
signals come from three main sources: noise on VCC, input signal changes on the channel being
converted (after the sample window has closed), and signals applied to channels not selected by
the multiplexer. The effects of these unwanted signals are specified as Vcc rejection, off-isolation,
and feedthrough, respectively. Finally, multiplexer on-channel resistances differ slightly from one
channel to the next, which causes channel-to-channel matching errors and repeatability errors.
Differences in DC leakage current from one channel to another and random noise in general con-
tribute to repeatability errors.
12-17
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8XC196MC, MD, MH USER’S MANUAL
7
6
IDEAL FULL-SCALE CODE
TRANSITION
IDEAL STRAIGHT LINE
TRANSFER FUNCTION
ACTUAL
FULL-SCALE CODE
TRANSITION
5
4
3
2
1
0
DIFFERENTIAL
NON-LINEARITY
(POSITIVE)
TERMINAL BASED
CHARACTERISTIC
(corrected for zero-offset
and full-scale error)
IDEAL
CODE WIDTH
ACTUAL
CHARACTERISTIC
NON-LINEARITY
DIFFERENTIAL
NON-LINEARITY (NEGATIVE)
IDEAL CODE WIDTH
ACTUAL FIRST TRANSITION
IDEAL FIRST TRANSITION
1/2
1
2
3
4
5
6
6 1/2
7
8
INPUT VOLTAGE (LSBs)
A0085-01
Figure 12-11. Terminal-based A/D Conversion Characteristic
12-18
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13
Minimum Hardware
Considerations
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CHAPTER 13
MINIMUM HARDWARE CONSIDERATIONS
The 8XC196MC, MD, and MH have several basic requirements for operation within a system.
This chapter describes options for providing the basic requirements and discusses other hardware
considerations.
13.1 MINIMUM CONNECTIONS
Table 13-1 lists the signals that are required for the device to function and Figure 13-1 shows the
connections for a minimum configuration.
Table 13-1. Minimum Required Signals
Signal
Type
Description
Name
ANGND
GND
Analog Ground
ANGND must be connected for A/D converter and port 0 operation (also port 1 on
the 8XC196MC and MD). ANGND and VSS should be nominally at the same
potential.
RESET#
I/O
Reset
A level-sensitive reset input to and open-drain system reset output from the micro-
controller. Either a falling edge on RESET# or an internal reset turns on a pull-down
transistor connected to the RESET# pin for 16 state times. In the powerdown and
idle modes, asserting RESET# causes the chip to reset and return to normal
operating mode. The 8XC196MH provides the option of preventing an internal reset
from generating a reset on the external pin (see “Resetting the Device” on page
13-8). After a device reset, the first instruction fetch is from 2080H.
VCC
VPP
PWR
PWR
Digital Supply Voltage
Connect each VCC pin to the digital supply voltage.
Programming Voltage
During programming, the VPP pin is typically at +12.5 V (VPP voltage). Exceeding the
maximum VPP voltage specification can damage the device.
VPP also causes the device to exit powerdown mode when it is driven low for at least
50 ns. Use this method to exit powerdown only when using an external clock source
because it enables the internal phase clocks, but not the internal oscillator.
On devices with no internal nonvolatile memory, connect VPP to VCC
Reference Voltage for the A/D Converter
.
VREF
PWR
GND
This pin also supplies operating voltage to both the analog portion of the A/D
converter and the logic used to read port 0 (also port 1 in the 8XC196MC and
8XC196MD).
VSS
Digital Circuit Ground
Connect each VSS pin to ground through the lowest possible impedance path.
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Table 13-1. Minimum Required Signals (Continued)
Signal
Name
Type
Description
XTAL1
I
Input Crystal/Resonator or External Clock Input
Input to the on-chip oscillator and the internal clock generators. The internal clock
generators provide the peripheral clocks, CPU clock, and CLKOUT signal (MC/MD
only). When using an external clock or crystal, instead of the on-chip oscillator,
connect the clock input to XTAL1. The external clock signal must meet the VIH speci-
fication for XTAL1 (see datasheet).
XTAL2
O
Inverted Output for the Crystal/Resonator
Output of the on-chip oscillator inverter. Leave XTAL2 floating when the design uses
an external clock source instead of the on-chip oscillator.
13.1.1 Unused Inputs
For predictable performance, it is important to tie unused inputs to VCC or VSS. Otherwise, they
can float to a mid-voltage level and draw excessive current. Unused interrupt inputs may generate
spurious interrupts if left unconnected.
13.1.2 I/O Port Pin Connections
Tie unused input-only port inputs to VSS as shown in Figure 13-1. Chapter 6, “I/O Ports,” contains
information about initializing and configuring the ports. Table 13-2 lists the sections, with page
numbers, that contain the information for each port.
Table 13-2. I/O Port Configuration Guide
Port
Port 0
Where to Find Configuration Information
“Standard Input-only Port Considerations” on page 6-4
Port 1
“Standard Input-only Port Considerations” on page 6-4 (MC, MD)
“Bidirectional Port Pin Configurations” on page 6-9 and “Bidirectional Port Considerations”
on page 6-12 (MH)
Port 2
“Bidirectional Port Pin Configurations” on page 6-9 and “Bidirectional Port Considerations”
on page 6-12
Ports 3 and 4 “Bidirectional Ports 3 and 4 (Address/Data Bus) Operation” on page 6-15
Port 5
“Bidirectional Port Pin Configurations” on page 6-9 and “Bidirectional Port Considerations”
on page 6-12
Port 6
“Configuring Output-only Port Pins” on page 6-17
Port 7 (MD)
“Bidirectional Port Pin Configurations” on page 6-9 and “Bidirectional Port Considerations”
on page 6-12
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MINIMUM HARDWARE CONSIDERATIONS
(Note 1)
20 pF
20 pF
VCC
XTAL2
XTAL1
RESET#
VCC
(Note 2)
0.01 µF
VCC
+
4.7 µF
VSS
EA#
NMI
VCC
1 M
BUSWIDTH
VPP
(Note 3)
VCC
VCC
+
READY
1 µF
VREF
+
1 µF
BHE#
RD#
ANGND
Port 5 / Bus Control
(Note 4)
WR#
Input-only
Port Pins
(Note 5)
INST
ALE
8XC196 Device
Notes:
1. See the datasheet for the oscillator frequency range (FXTAL1) and the crystal manufacturer's
datasheet for recommended load capacitors.
2. The number of VCC and VSS pins varies with package type (see datasheet). Be sure to connect
each VCC pin to the supply voltage and each VSS pin to ground.
3. Connect the RC network to VPP only if powerdown mode will be used. Otherwise, connect VPP
to VCC.
4. No connection is required.
5. Tie all input-only port pins to VSS.
A2643-03
Figure 13-1. Minimum Hardware Connections
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13.2 APPLYING AND REMOVING POWER
When power is first applied to the device, RESET# must remain continuously low for at least one
state time after the power supply is within tolerance and the oscillator/clock has stabilized; oth-
erwise, operation might be unpredictable. Similarly, when powering down a system, RESET#
should be brought low before VCC is removed; otherwise, an inadvertent write to an external lo-
cation might occur. Carefully evaluate the possible effect of power-up and power-down sequenc-
es on a system.
13.3 NOISE PROTECTION TIPS
The fast rise and fall times of high-speed CMOS logic often produce noise spikes on the power
supply lines and outputs. To minimize noise, it is important to follow good design and board lay-
out techniques. We recommend liberal use of decoupling capacitors and transient absorbers. Add
0.01 µF bypass capacitors between VCC and each VSS pin and a 1.0 µF capacitor between VREF and
ANGND to reduce noise (Figure 13-2). Place the capacitors as close to the device as possible.
Use the shortest possible path to connect VSS lines to ground and each other.
V
REF
+
+
V
REF
8XC196 Device
1.0 µF
–
ANGND
†
Analog
Ground
Plane
†
Digital
†
Ground
Plane
+5 V
5 V
Return
Power Source
†
Use 0.01 µF bypass capacitors for maximum decoupling.
A0272-02
Figure 13-2. Power and Return Connections
13-4
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MINIMUM HARDWARE CONSIDERATIONS
If the A/D converter will be used, connect VREF to a separate reference supply to minimize noise
during A/D conversions. Even if the A/D converter will not be used, VREF and ANGND must be
connected to provide power to port 0. On the 8XC196MC and MD, they also provide power to
port 1. Refer to “Analog Ground and Reference Voltages” on page 12-12 for a detailed discussion
of A/D power and ground recommendations.
Multilayer printed circuit boards with separate VCC and ground planes also help to minimize
noise. For more information on noise protection, refer to AP-125, Designing Microcontroller Sys-
tems for Noisy Environments and AP-711, EMI Design Techniques for Microcontrollers in Auto-
motive Applications.
13.4 THE ON-CHIP OSCILLATOR CIRCUITRY
The on-chip oscillator circuit (Figure 13-3) consists of a crystal-controlled, positive reactance os-
cillator. In this application, the crystal operates in a parallel resonance mode. The feedback resis-
tor, Rf, consists of paralleled n-channel and p-channel FETs controlled by the internal powerdown
signal. In powerdown mode, Rf acts as an open and the output drivers are disabled, which disables
the oscillator. Both the XTAL1 and XTAL2 pins have built-in electrostatic discharge (ESD) pro-
tection.
To internal
circuitry
V
CC
Rf
XTAL2
XTAL1
(Input)
(Output)
Oscillator Enable#
(from powerdown circuitry)
V
SS
A0076-03
Figure 13-3. On-chip Oscillator Circuit
13-5
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Figure 13-4 shows the connections between the external crystal and the device. When designing
an external oscillator circuit, consider the effects of parasitic board capacitance, extended oper-
ating temperatures, and crystal specifications. Consult the manufacturer’s datasheet for perfor-
mance specifications and required capacitor values. With high-quality components, 20 pF load
capacitors (CL) are usually adequate for frequencies above 1 MHz.
Noise spikes on the XTAL1 or XTAL2 pin can cause a miscount in the internal clock-generating
circuitry. Capacitive coupling between the crystal oscillator and traces carrying fast-rising digital
signals can introduce noise spikes. To reduce this coupling, mount the crystal oscillator and ca-
pacitors near the device and use short, direct traces to connect to XTAL1, XTAL2, and VSS. To
further reduce the effects of noise, use grounded guard rings around the oscillator circuitry and
ground the metallic crystal case.
C1
XTAL1
®
MCS 96
Microcontroller
XTAL2
C2
Quartz Crystal
Note:
Mount the crystal and capacitors close to the device using
short, direct traces to XTAL1, XTAL2, and V . When
ss
using a crystal, C1=C2≈20 pF. When using a ceramic
resonator, consult the manufacturer for recommended
oscillator circuitry.
A0273-03
Figure 13-4. External Crystal Connections
In cost-sensitive applications, you may choose to use a ceramic resonator instead of a crystal os-
cillator. Ceramic resonators may require slightly different load capacitor values and circuit con-
figurations. Consult the manufacturer’s datasheet for the requirements.
13-6
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MINIMUM HARDWARE CONSIDERATIONS
13.5 USING AN EXTERNAL CLOCK SOURCE
To use an external clock source, apply a clock signal to XTAL1 and let XTAL2 float (Figure
13-5). To ensure proper operation, the external clock source must meet the minimum high and
low times (TXHXX and TXLXX) and the maximum rise and fall transition times (TXLXH and TXHXL
)
(Figure 13-6). The longer the rise and fall times, the higher the probability that external noise will
affect the clock generator circuitry and cause unreliable operation. See the datasheet for required
XTAL1 voltage drive levels and actual specifications.
V
CC
†
4.7 kΩ
External
XTAL1
XTAL2
Clock Input
®
MCS 96
Clock Driver
No Connection
Microcontroller
†
Required if TTL driver is used. Not needed if CMOS driver is used.
A0274-03
Figure 13-5. External Clock Connections
TXHXL
TXHXX
TXLXH
0.7 VCC + 0.5 V
0.7 VCC + 0.5 V
0.3 VCC – 0.5 V
TXLXL
TXLXX
0.3 VCC – 0.5 V
XTAL1
A2119-02
Figure 13-6. External Clock Drive Waveforms
At power-on, the interaction between the internal amplifier and its feedback capacitance (i.e., the
Miller effect) may cause a load of up to 100 pF at the XTAL1 pin if the signal at XTAL1 is weak
(such as might be the case during start-up of the external oscillator). This situation will go away
when the XTAL1 input signal meets the VIL and VIH specifications (listed in the datasheet). If
these specifications are met, the XTAL1 pin capacitance will not exceed 20 pF.
13-7
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13.6 RESETTING THE DEVICE
Reset forces the device into a known state. As soon as RESET# is asserted, the I/O pins, the con-
trol pins, and the registers are driven to their reset states. (Tables in Appendix B list the reset states
of the pins (see Table B-8 on page B-23 for the 8XC196MC and 8XC196MD or Table B-9 on
page B-25 for the 8XC196MH). See Table C-2 on page C-2 for the reset values of the SFRs.) The
device remains in its reset state until RESET# is deasserted. When RESET# is deasserted, the bus
controller fetches the chip configuration bytes (CCBs), loads them into the chip configuration
registers (CCRs), and then fetches the first instruction.
Figure 13-7 shows the reset-sequence timing. Depending upon when RESET# is brought high,
the CLKOUT signal (MC and MD only) may become out of phase with the PH1 internal clock.
When this occurs, the clock generator immediately resynchronizes CLKOUT as shown in Case 2.
Internal
Reset
RESET#
Pin
Case 1
CLKOUT
(MC, MD
Only)
Case 2
CLKOUT
= ADV# Selected
XTAL1
Phases Resynchronized
9 T
9 T
XTAL1
8 T
ALE
RD#
XTAL1
7 T
XTAL1
7 T
7 T
XTAL1
CCB0
XTAL1
CCB1
9 T
11 T
XTAL1
XTAL1
AD7:0
AD15:8
18H
20H
1AH
80H
20H
†
†
Weak
Weak
20H
Bus parameters defined by CCB0 (ready
control, bus width, and bus-timing
modes) take effect here.
†Defaults to an 8-bit bus until the CCBs are loaded. AD15:8 weakly drive address during the CCB fetches.
For 16-bit systems, write 20H to the high byte of CCB0 and CCB1 (2019H and 201BH) in order to prevent
bus contention.
A3088-02
Figure 13-7. Reset Timing Sequence
13-8
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MINIMUM HARDWARE CONSIDERATIONS
The 8XC196MH provides the option of an internal-only reset or an internal reset that is also re-
flected externally (by the RESET# pin). The GEN_CON register controls whether an internal re-
set asserts the external RESET# signal and indicates the source of the most recent reset. Figure
13-8 describes the general configuration register, GEN_CON.
Address:
Reset State:
1FA0H
00H
GEN_CON
(8XC196MH)
The GEN_CON register controls whether an internal reset asserts the external RESET# signal and
indicates the source of the most recent reset.
7
0
8XC196MH
RSTS
—
—
—
—
—
—
DR0
Bit
Number
Bit
Mnemonic
Function
7
RSTS
Reset source (read-only status bit)
0 = external reset (RESET# pin asserted)
1 = internal reset (watchdog overflow, illegal IDLPD key, or RST
instruction)
6:1
0
—
Reserved; for compatibility with future devices, write zeros to these bits.
DRO
Disable RESET# out
0 = an internal reset asserts the RESET# pin.
1 = an internal reset has no effect on the RESET# pin; the RESET# pin is
pulled high (inactive).
Figure 13-8. General Configuration Register (GEN_CON)
The following events will reset the device (see Figure 13-9):
• an external device pulls the RESET# pin low
• the CPU issues the reset (RST) instruction
• the CPU issues an idle/powerdown (IDLPD) instruction with an illegal key operand
• the watchdog timer (WDT) overflows
The following paragraphs describe each of these reset methods in more detail.
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Internal
External
V
CC
Clock
Reset State
Internal
Reset
Signal
Machine
R
†
Trigger
RST
Count Complete
CLR
RESET#
~200 Ω
Q
Q1
GEN_CON.0
(MH Only)
SET
RST Instruction
WDT Overflow
IDLPD Invalid Key
† See the datasheet for minimum and maximum RRST values.
A3086-01
Figure 13-9. Internal Reset Circuitry
13.6.1 Generating an External Reset
To reset the device, hold the RESET# pin low for at least one state time after the power supply is
within tolerance and the oscillator has stabilized. When RESET# is first asserted, the device turns
on a pull-down transistor (Q1) for 16 state times. This enables the RESET# signal to function as
the system reset.
The simplest way to reset the device is to insert a capacitor between the RESET# pin and VSS, as
shown in Figure 13-10. The device has an internal pull-up resistor (RRST) shown in Figure 13-9.
RESET# should remain asserted for at least one state time after VCC and XTAL1 have stabilized
and met the operating conditions specified in the datasheet. A capacitor of 4.7 µF or greater
should provide sufficient reset time, as long as VCC rises quickly.
13-10
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MINIMUM HARDWARE CONSIDERATIONS
RESET#
+
4.7 µF
®
MCS 96
Microcontroller
A0276-02
Figure 13-10. Minimum Reset Circuit
Other devices in the system may not be reset because the capacitor will keep the voltage above
VIL. Since RESET# is asserted for only 16 state times, it may be necessary to lengthen and buffer
the system-reset pulse. Figure 13-11 shows an example of a system-reset circuit. In this example,
D2 creates a wired-OR gate connection to the reset pin. An internal reset, system power-up, or
SW1 closing will generate the system-reset signal.
V
CC
V
CC
(1)
D1
(2)
R
D2
4.7 kΩ
RESET#
SW1
®
C
MCS 96
Schmitt Triggers
Microcontroller
System reset signal
to external circuitry
Notes:
1. D1 provides a faster cycle time for repetitive power-on resets.
2. Optional pull-up for faster recovery.
A0277-03
Figure 13-11. Example of a System Reset Circuit
13-11
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13.6.2 Issuing the Reset (RST) Instruction
The RST instruction (opcode FFH) resets the device by pulling RESET# low for 16 state times.
It also clears the processor status word (PSW), sets the master program counter (PC) to 2080H,
and resets the special function registers (SFRs). See Table C-2 on page C-2 for the reset values
of the SFRs.
Putting pull-ups on the address/data bus causes unimplemented areas of memory to be read as
FFH. If unused internal OTPROM memory is set to FFH, then execution from any unused mem-
ory locations will reset the device.
13.6.3 Issuing an Illegal IDLPD Key Operand
The device resets itself if an illegal key operand is used with the idle/powerdown (IDLPD) com-
mand. The legal keys are “1” for idle mode and “2” for powerdown mode. If any other value is
used, the device executes a reset sequence. (See Appendix A for a description of the IDLPD com-
mand.)
13.6.4 Generating Wait States
The 8XC196Mx devices can interface with a variety of external memory devices. With slower
external devices this requires inserting wait states to lengthen the bus cycle. An external device
can use the READY input to request wait states in addition to the wait states that are generated
internally by the 8XC196Mx device. The READY signal must be held valid until the TCLYX (for
the 8XC196MC, MD) or TLLYX (for the 8XC196MH) timing specification is met. Do not exceed
the maximum TCLYX (for the 8XC196MC, MD) or TLLYX (for the 8XC196MH) specification or
additional (unwanted) wait states might be added (see Chapter 15, “Wait States (Ready Control),”
for a detailed explanation).
13.6.5 Enabling the Watchdog Timer
The watchdog timer (WDT) is a 16-bit counter that resets the device when the counter overflows.
The WDE bit (bit 3) of CCR1 controls whether the watchdog is enabled immediately or is dis-
abled until the first time it is cleared. Clearing WDE activates the watchdog. Setting WDE makes
the watchdog timer inactive, but you can activate it by clearing the watchdog register. Once the
watchdog is activated, only a reset can disable it.
The 8XC196MC and 8XC196MD allow only one reset interval, 64K state times. This requires
your software to interrupt itself every 65,535 state times to reset the watchdog. The 8XC196MH
allows you to choose a longer interval.
13-12
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MINIMUM HARDWARE CONSIDERATIONS
You must write two consecutive bytes to the watchdog register (location 0AH) to clear it. For the
8XC196MC and MD, the first byte must be 1EH and the second must be E1H. For the
8XC196MH, the first byte must also be 1EH; however, the second byte can be one of four values.
The second byte determines the reset interval (Table 13-3). Only the values listed in the table are
valid; an invalid value will not clear the register, so the counter will overflow and the watchdog
will reset the device. We recommend that you disable interrupts before writing to the watchdog
register. If an interrupt occurs between the two writes, the watchdog register will not be cleared.
Table 13-3. Selecting the Watchdog Reset Interval (8XC196MH only)
First Byte
Second Byte
Reset Interval
64K states
1EH
1EH
1EH
1EH
E1H
A1H
61H
21H
128K states (2 × 64K)
256K states (4 × 64K)
512K states (8 × 64K)
NOTE (8XC196MH Only)
If the WDE bit of CCR1 is cleared, the watchdog is activated immediately
after a system power-up or a device reset. You must clear the watchdog register
within 64K state times after a system power-up or a device reset. At that time,
you can choose a longer interval for subsequent watchdog resets.
If enabled, the watchdog continues to run in idle mode. The device must be awakened before the
end of the reset interval to clear the watchdog; otherwise, the watchdog will reset the device,
which causes it to exit idle mode.
13-13
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14
Special Operating
Modes
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CHAPTER 14
SPECIAL OPERATING MODES
The 8XC196MC, MD, and MH provide two power saving modes: idle and powerdown. They
also provide an on-circuit emulation (ONCE) mode that electrically isolates the device from the
other system components. This chapter describes each mode and explains how to enter and exit
each. (Refer to Appendix A for descriptions of the instructions discussed in this chapter, to Ap-
pendix B for descriptions of signal status during each mode, and to Appendix C for details about
the registers.)
14.1 SPECIAL OPERATING MODE SIGNALS AND REGISTERS
Table 14-1 lists the signals and Table 14-2 lists the registers that are mentioned in this chapter.
Table 14-1. Operating Mode Control Signals
Signal
Port Pin
Type
Description
Name
P2.7
CLKOUT
(MC/MD
only)
O
Clock Output
Output of the internal clock generator. The CLKOUT frequency is ½
the oscillator input frequency (FXTAL1). CLKOUT has a 50% duty cycle.
CLKOUT is not implemented on the 8XC196MH.
External Interrupt
—
EXTINT
I
This programmable interrupt is controlled by the WG_PROTECT
register. This register controls whether the interrupt is edge triggered
or sampled and whether a rising edge/high level or falling edge/low
level activates the interrupt.
In powerdown mode, asserting the EXTINT signal for at least 50 ns
causes the device to resume normal operation. The interrupt need not
be enabled. If the EXTINT interrupt is enabled, the CPU executes the
interrupt service routine. Otherwise, the CPU executes the instruction
that immediately follows the command that invoked the power-saving
mode.
In idle mode, asserting any enabled interrupt causes the device to
resume normal operation.
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Table 14-1. Operating Mode Control Signals (Continued)
Signal
Name
Port Pin
Type
Description
P5.4
ONCE#
I
On-circuit Emulation
Holding ONCE# low during the rising edge of RESET# places the
device into on-circuit emulation (ONCE) mode. This mode puts all
pins, except XTAL1 and XTAL2, into a high-impedance state, thereby
isolating the device from other components in the system. The value
of ONCE# is latched when the RESET# pin goes inactive. While the
device is in ONCE mode, you can debug the system using a clip-on
emulator. To exit ONCE mode, reset the device by pulling the
RESET# signal low. To prevent inadvertent entry into ONCE mode,
either configure this pin as an output or hold it high during reset and
ensure that your system meets the VIH specification (see datasheet).
P2.6
Test-mode
entry
I/O
I/O
Test-mode entry
If this pin is held low during reset, the device will enter a reserved test
mode, so exercise caution if you use this pin for input. If you choose
to configure this pin as an input, always hold it high during reset and
ensure that your system meets the VIH specification (see datasheet)
to prevent inadvertent entry into a test mode.
—
RESET#
Reset
A level-sensitive reset input to and open-drain system reset output
from the microcontroller. Either a falling edge on RESET# or an
internal reset turns on a pull-down transistor connected to the
RESET# pin for 16 state times. In the powerdown and idle modes,
asserting RESET# causes the chip to reset and return to normal
operating mode. The 8XC196MH provides the option of preventing an
internal reset from generating a reset on the external pin (see
“Resetting the Device” on page 13-8). After a device reset, the first
instruction fetch is from 2080H.
—
VPP
PWR
Programming Voltage
During programming, the VPP pin is typically at +12.5 V (VPP voltage).
Exceeding the maximum VPP voltage specification can damage the
device.
VPP also causes the device to exit powerdown mode when it is driven
low for at least 50 ns. Use this method to exit powerdown only when
using an external clock source because it enables the internal phase
clocks, but not the internal oscillator.
On devices with no internal nonvolatile memory, connect VPP to VCC
.
Table 14-2. Operating Mode Control and Status Registers
Address Description
2018H Chip Configuration 0 Register
Mnemonic
CCR0
Bit 0 of this register enables and disables powerdown mode.
Interrupt Mask 1
INT_MASK1
0013H
Bit 6 of this 8-bit register enables and disables (masks) the
external interrupt (EXTINT).
14-2
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SPECIAL OPERATING MODES
Table 14-2. Operating Mode Control and Status Registers (Continued)
Mnemonic
Address
Description
P1_DIR (MH)
P2_DIR
P5_DIR
1F9BH
Port x Direction
1FD2H
1FF3H
1FD3H
Each bit of Px_DIR controls the direction of the corresponding pin.
Clearing a bit configures a pin as a complementary output; setting
a bit configures a pin as an input or open-drain output. (Open-
drain outputs require external pull-ups.)
P7_DIR (MD)
P1_MODE(MH) 1F99H
Port x Mode
P2_MODE
P5_MODE
P7_MODE(MD) 1FD1H
1FD0H
1FF1H
Each bit of Px_MODE controls whether the corresponding pin
functions as a standard I/O port pin or as a special-function
signal. Setting a bit configures a pin as a special-function signal;
clearing a bit configures a pin as a standard I/O port pin.
P1_REG (MH)
P2_REG
P5_REG
1F9DH
1FD4H
1FF5H
1FD5H
Port x Data Output
For an input, set the corresponding Px_REG bit.
For an output, write the data to be driven out by each pin to the
corresponding bit of Px_REG. When a pin is configured as
standard I/O (Px_MODE.y = 0), the result of a CPU write to
Px_REG is immediately visible on the pin. When a pin is
configured as a special-function signal (Px_MODE.y = 1), the
associated on-chip peripheral or off-chip component controls the
pin. The CPU can still write to Px_REG, but the pin is unaffected
until it is switched back to its standard I/O function.
P7_REG (MD)
This feature allows software to configure a pin as standard I/O
(clear Px_MODE.y), initialize or overwrite the pin value, then
configure the pin as a special-function signal (set Px_MODE.y). In
this way, initialization, fault recovery, exception handling, etc., can
be done without changing the operation of the associated
peripheral.
14.2 REDUCING POWER CONSUMPTION
Both power-saving modes conserve power by disabling portions of the internal clock circuitry
(Figure 14-1). The following paragraphs describe both modes in detail.
14-3
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Disable Clock Input
(Powerdown)
FXTAL1
Divide-by-two
Circuit
XTAL1
XTAL2
Disable Clocks
(Powerdown)
Peripheral Clocks (PH1, PH2)
CLKOUT
Clock
Generators
Disable
Oscillator
CPU Clocks (PH1, PH2)
(Powerdown)
Disable Clocks
(Idle, Powerdown)
NOTE: The CLKOUT pin is unique to the 8XC196MC and MD.
A3115-02
Figure 14-1. Clock Control During Power-saving Modes
14.3 IDLE MODE
In idle mode, the device’s power consumption decreases to approximately 40% of normal con-
sumption. Internal logic holds the CPU clocks at logic zero, causing the CPU to stop executing
instructions. Neither the peripheral clocks nor CLKOUT are affected, so the special-function reg-
isters (SFRs) and register RAM retain their data and the peripherals and interrupt system remain
active. Tables in Appendix B list the values of the pins during idle mode (see Table B-8 on page
B-23 for the 8XC196MC and 8XC196MD or Table B-9 on page B-25 for the 8XC196MH).
14-4
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SPECIAL OPERATING MODES
The device enters idle mode after executing the IDLPD #1 instruction. Any enabled interrupt
source, either internal or external, or a hardware reset can cause the device to exit idle mode.
When an interrupt occurs, the CPU clocks restart and the CPU executes the corresponding inter-
rupt service or PTS routine. When the routine is complete, the CPU fetches and then executes the
instruction that follows the IDLPD #1 instruction.
NOTE
If enabled, the watchdog timer continues to run in idle mode. The device must
be awakened before the counter overflows; otherwise, the timer will reset the
device. The watchdog timer interval is always 64K state times in the
8XC196MC and MD, but a longer interval can be selected in the 8XC196MH
(see “Enabling the Watchdog Timer” on page 13-12).
To prevent an accidental return to full power, hold the external interrupt pin
(EXTINT) low while the device is in idle mode.
14.4 POWERDOWN MODE
Powerdown mode places the device into a very low power state by disabling the internal oscilla-
tor and clock generators. Internal logic holds the CPU and peripheral clocks at logic zero, which
causes the CPU to stop executing instructions, the system bus-control signals to become inactive,
the CLKOUT signal to become high, and the peripherals to turn off. Power consumption drops
into the microwatt range (refer to the datasheet for exact specifications). ICC is reduced to device
leakage. Tables in Appendix B list the values of the pins during powerdown mode (see Table B-8
on page B-23 for the 8XC196MC and 8XC196MD or Table B-9 on page B-25 for the
8XC196MH). If VCC is maintained above the minimum specification, the special-function regis-
ters (SFRs) and register RAM retain their data.
14.4.1 Enabling and Disabling Powerdown Mode
The PD bit in the chip configuration register 0 (CCR0.0) either enables or disables powerdown
mode. Because CCR0 cannot be accessed by code, the PD bit value is defined in chip configura-
tion byte 0 (CCB0.0). Setting the PD bit enables powerdown mode and clearing it disables pow-
erdown. CCR0 is loaded from CCB0 when the device returns from reset. Refer to “Operating
Environment” on page 16-17 for descriptions of the methods for programming the CCBs.
14-5
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14.4.2 Entering Powerdown Mode
Before entering powerdown, complete the following tasks:
• Complete all serial port transmissions or receptions. Otherwise, when the device exits
powerdown, the serial port activity will continue where it left off and incorrect data may be
transmitted or received.
• Complete all analog conversions. If powerdown occurs during the conversion, the result
will be incorrect.
• If the watchdog timer (WDT) is enabled, clear the WATCHDOG register just before issuing
the powerdown instruction. This ensures that the device can exit powerdown cleanly.
Otherwise, the WDT could reset the device before the oscillator stabilizes. (The WDT
cannot reset the device during powerdown because the clock is stopped.)
• Put all other peripherals into an inactive state.
After completing these tasks, execute the IDLPD #2 instruction to enter powerdown mode.
NOTE
To prevent an accidental return to full power, hold the external interrupt pin
(EXTINT) low while the device is in powerdown mode.
14.4.3 Exiting Powerdown Mode
The device will exit powerdown mode when any of the following events occurs:
• an external device drives the VPP pin low for at least 50 ns
• a hardware reset is generated
• a transition occurs on the external interrupt pin
14.4.3.1
Driving the VPP Pin Low
If the design uses an external clock input signal rather than the on-chip oscillator, the fastest way
to exit powerdown mode is to drive the VPP pin low for at least 50 ns. Use this method only when
using an external clock input because the internal CPU and peripheral clocks will be enabled, but
the internal oscillator will not.
14.4.3.2
Generating a Hardware Reset
The device will exit powerdown if RESET# is asserted. If the design uses an external clock input
signal rather than the on-chip oscillator, RESET# must remain low for at least 16 state times. If
the design uses the on-chip oscillator, then RESET# must be held low until the oscillator has sta-
bilized.
14-6
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SPECIAL OPERATING MODES
14.4.3.3
Asserting the External Interrupt Signal
The final way to exit powerdown mode is to assert the external interrupt signal (EXTINT) for at
least 50 ns. Although EXTINT is normally a sampled input, the powerdown circuitry uses it as a
level-sensitive input. The interrupt need not be enabled to bring the device out of powerdown, but
the pin must be configured as a special-function input (see “Bidirectional Port Pin Configura-
tions” on page 6-9). Figure 14-2 shows the power-up and power-down sequence when using an
external interrupt to exit powerdown.
When an external interrupt brings the device out of powerdown mode, the corresponding pending
bit is set in the interrupt pending register. If the interrupt is enabled, the device executes the in-
terrupt service routine, then fetches and executes the instruction following the IDLPD #2 instruc-
tion. If the interrupt is disabled (masked), the device fetches and executes the instruction
following the IDLPD #2 instruction and the pending bit remains set until the interrupt is serviced
or software clears the pending bit.
XTAL1
CLKOUT
PH1
Internal Powerdown
Signal
EXTINT
V
PP
Timeout
(Internal)
A0078-01
Figure 14-2. Power-up and Power-down Sequence When Using an External Interrupt
When using an external interrupt signal to exit powerdown mode, we recommend that you con-
nect the external RC circuit shown in Figure 14-3 to the VPP pin. The discharging of the capacitor
causes a delay that allows the oscillator to stabilize before the internal CPU and peripheral clocks
are enabled.
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V
CC
8XC196
Device
R
1 MΩ Typical
1
V
PP
C
1µF Typical
1
A0279-01
Figure 14-3. External RC Circuit
During normal operation (before entering powerdown mode), an internal pull-up holds the
VPP pin at VCC. When an external interrupt signal is asserted, the internal oscillator circuitry is
enabled and turns on a weak internal pull-down. This weak pull-down causes the external capac-
itor (C1) to begin discharging at a typical rate of 200 µA. When the VPP pin voltage drops below
the threshold voltage (about 2.5 V), the internal phase clocks are enabled and the device resumes
code execution.
At this time, the internal pull-up transistor turns on and quickly pulls the pin back up to about
3.5 V. The pull-up becomes ineffective and the external resistor (R1) takes over and pulls the volt-
age up to VCC (see recovery time in Figure 14-4). The time constant follows an exponential charg-
ing curve. If R1 = 1 MΩ and C1 = 1 µF, the recovery time will be one second.
14.4.3.4
Selecting R1 and C1
The values of R1 and C1 are not critical. Select components that produce a sufficient discharge
time to permit the internal oscillator circuitry to stabilize. Because many factors can influence the
discharge time requirement, you should always fully characterize your design under worst-case
conditions to verify proper operation.
14-8
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SPECIAL OPERATING MODES
5
4
EXTINT
3
200 µA C Discharge
1
R
x C Recovery
V
, Volts
1
1
PP
Time Constant
2
Pullup On
Code Execution Resumes
1
2
4
6
8
10
12
14
16
18
20
22
Time, ms
A0151-01
Figure 14-4. Typical Voltage on the VPP Pin While Exiting Powerdown
Select a resistor that will not interfere with the discharge current. In most cases, values between
200 kΩ and 1 MΩ should perform satisfactorily.
14-9
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When selecting the capacitor, determine the worst-case discharge time needed for the oscillator
to stabilize, then use this formula to calculate an appropriate value for C1.
TDIS × I
-------------------
C1
=
Vt
where:
C1
TDIS
I
is the capacitor value, in farads
is the worst-case discharge time, in seconds
is the discharge current, in amperes
is the threshold voltage
V
t
NOTE
If powerdown is re-entered and exited before C1 charges to VCC, it will take
less time for the voltage to ramp down to the threshold. Therefore, the device
will take less time to exit powerdown.
For example, assume that the oscillator needs at least 12.5 ms to discharge (TDIS = 12.5 ms), V
t
is 2.5 V, and the discharge current is 200 µA. The minimum C1 capacitor size is 1 µF.
(0.0125) (0.0002)
--------------------------------------------------
= 1 µF
C 1
=
2.5
When using an external oscillator, the value of C1 can be very small, allowing rapid recovery from
powerdown. For example, a 100 pF capacitor discharges in 1.25 µs.
(1.0 × 10–10) (2.5)
C1 × Vt
------------------
--------------------------------------------------
= 1.25 µs
TDIS
=
=
I
0.0002
14.5 ONCE MODE
On-circuit emulation (ONCE) mode isolates the device from other components in the system to
allow printed-circuit-board testing or debugging with a clip-on emulator. During ONCE mode,
all pins except XTAL1, XTAL2, VSS, and, VCC are weakly pulled high or low. During ONCE
mode, RESET# must be held high or the device will exit ONCE mode and enter the reset state.
14-10
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SPECIAL OPERATING MODES
Holding the ONCE# signal low during the rising edge of RESET# causes the device to enter
ONCE mode. To prevent accidental entry into ONCE mode, we highly recommend configuring
this pin as an output. If you choose to configure this pin as an input, always hold it high during
reset and ensure that your system meets the VIH specification (see datasheet) to prevent inadvert-
ent entry into ONCE mode.
Exit ONCE mode by asserting the RESET# signal and allowing the ONCE# pin to float or be
pulled high. Normal operations resume when RESET# goes high.
14.6 RESERVED TEST MODES
A special test-mode-entry pin (P2.6) is provided for Intel’s in-house testing only. These test
modes can be entered accidentally if you configure the test-mode-entry pin as an input and hold
it low during the rising edge of RESET#. To prevent accidental entry into an unsupported test
mode, we highly recommend configuring the test-mode-entry pin as an output. If you choose to
configure this pin as an input, always hold it high during reset and ensure that your system meets
theVIH specification (see datasheet) to prevent inadvertent entry into an unsupported test mode.
14-11
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15
Interfacing with
External Memory
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CHAPTER 15
INTERFACING WITH EXTERNAL MEMORY
The microcontroller can interface with a variety of external memory devices. It supports either a
fixed 8-bit data bus width, a fixed 16-bit data bus width, or a dynamic 8-bit/16-bit data bus width;
internal control of wait states for slow external memory devices; and several bus-control modes.
These features provide a great deal of flexibility when interfacing with external memory systems.
In addition to describing the signals and registers related to external memory, this chapter discuss-
es the process of fetching the chip configuration bytes and configuring the external bus. It also
provides examples of external memory configurations.
15.1 EXTERNAL MEMORY INTERFACE SIGNALS AND REGISTERS
Table 15-1 lists the signals and Table 15-2 lists the registers that are mentioned in this chapter.
Many of the external memory interface signals are multiplexed with standard I/O port signals, as
shown in the Port Pin column. Table 15-3 gives the port register settings to configure the pins as
external memory interface signals rather than standard I/O port signals. See Chapter 6, “I/O
Ports,” to configure the pins as standard I/O port signals.
Table 15-1. External Memory Interface Signals
Signal
Port Pin
Type
Description
Name
AD15:0
P4.7:0
P3.7:0
I/O
Address/Data Lines
These pins provide a multiplexed address and data bus. During the
address phase of the bus cycle, address bits 0–15 are presented on
the bus and can be latched using ALE or ADV#. During the data
phase, 8- or 16-bit data is transferred.
ADV#
P5.0
O
Address Valid
This active-low output signal is asserted only during external memory
accesses. ADV# indicates that valid address information is available
on the system address/data bus. The signal remains low while a valid
bus cycle is in progress and is returned high as soon as the bus cycle
completes.
An external latch can use this signal to demultiplex the address from
the address/data bus. A decoder can also use this signal to generate
chip selects for external memory.
15-1
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Table 15-1. External Memory Interface Signals (Continued)
Signal
Name
Port Pin
P5.0
Type
Description
ALE
O
Address Latch Enable
This active-high output signal is asserted only during external memory
cycles. ALE signals the start of an external bus cycle and indicates
that valid address information is available on the system address/data
bus. ALE differs from ADV# in that it does not remain active during the
entire bus cycle.
An external latch can use this signal to demultiplex the address from
the address/data bus.
BHE#
P5.5
O
Byte High Enable†
During 16-bit bus cycles, this active-low output signal is asserted for
word and high-byte reads and writes to external memory. BHE#
indicates that valid data is being transferred over the upper half of the
system data bus. Use BHE#, in conjunction with AD0, to determine
which memory byte is being transferred over the system bus:
BHE#
AD0 Byte(s) Accessed
0
0
1
0
1
0
both bytes
high byte only
low byte only
†
The chip configuration register 0 (CCR0) determines whether this
pin functions as BHE# or WRH#. CCR0.2 = 1 selects BHE#;
CCR0.2 = 0 selects WRH#.
BUSWIDTH P5.7
I
Bus Width
Two chip configuration register bits, CCR0.1 and CCR1.2, along with
the BUSWIDTH pin, control the data bus width. When both CCR bits
are set, the BUSWIDTH signal selects the external data bus width.
When only one CCR bit is set, the bus width is fixed at either 16 or 8
bits, and the BUSWIDTH signal has no effect.
CCR0.1 CCR1.2 BUSWIDTH
0
1
1
1
1
0
1
1
X
X
high
low
fixed 8-bit data bus
fixed 16-bit data bus
16-bit data bus
8-bit data bus
CLKOUT
(MC, MD)
—
O
Clock Output
Output of the internal clock generator. The CLKOUT frequency is ½
the oscillator input frequency (FXTAL1). CLKOUT has a 50% duty cycle.
15-2
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INTERFACING WITH EXTERNAL MEMORY
Table 15-1. External Memory Interface Signals (Continued)
Signal
Name
Port Pin
Type
Description
EA#
—
I
External Access
This input determines whether memory accesses to special-purpose
and program memory partitions are directed to internal or external
memory. (See Table 4-1 on page 4-2 for address ranges of special-
purpose and program memory partitions.) These accesses are
directed to internal memory if EA# is held high and to external
memory if EA# is held low. For an access to any other memory
location, the value of EA# is irrelevant.
EA# also controls entry into the programming modes. If EA# is at VPP
voltage (typically +12.5 V) on the rising edge of RESET#, the micro-
controller enters a programming mode.
NOTE: Systems with EA# tied inactive have idle time between
external bus cycles. When the address/data bus is idle, you
can use ports 3 and 4 for I/O. Systems with EA# tied active
cannot use ports 3 and 4 as standard I/O; when EA# is
active, these ports will function only as the address/data bus.
EA# is sampled and latched only on the rising edge of RESET#.
Changing the level of EA# after reset has no effect.
Always connect EA# to VSS when using a microcontroller that has no
internal nonvolatile memory.
INST
P5.1
O
Instruction Fetch
This active-high output signal is valid only during external memory bus
cycles. When high, INST indicates that an instruction is being fetched
from external memory. The signal remains high during the entire bus
cycle of an external instruction fetch. INST is low for data accesses,
including interrupt vector fetches and chip configuration byte reads.
INST is low during internal memory fetches.
RD#
P5.3
P5.6
O
I
Read
Read-signal output to external memory. RD# is asserted only during
external memory reads.
READY
Ready Input
This active high input along with the chip configuration registers
determine the number of wait states inserted into the bus cycle. The
chip configuration registers selects the maximum number of wait
states (0, 1, 2, 3, or infinite) that can be inserted into the bus cycle.
While READY is low, wait states are inserted into the bus cycle until
the programmed number of wait states is reached. If READY is pulled
high before the programmed number of wait states is reached, no
additional wait states will be inserted into the bus cycle.
WR#
P5.2
O
Write†
This active-low output indicates that an external write is occurring.
This signal is asserted only during external memory writes.
†
The chip configuration register 0 (CCR0) determines whether this
pin functions as WR# or WRL#. CCR0.2 = 1 selects WR#; CCR0.2 =
0 selects WRL#.
15-3
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Table 15-1. External Memory Interface Signals (Continued)
Signal
Name
Port Pin
P5.5
Type
Description
WRH#
O
Write High†
During 16-bit bus cycles, this active-low output signal is asserted for
high-byte writes and word writes to external memory. During 8-bit bus
cycles, WRH# is asserted for all write operations.
†
The chip configuration register 0 (CCR0) determines whether this
pin functions as BHE# or WRH#. CCR0.2 = 1 selects BHE#;
CCR0.2 = 0 selects WRH#.
WRL#
P5.2
O
Write Low†
During 16-bit bus cycles, this active-low output signal is asserted for
low-byte writes and word writes to external memory. During 8-bit bus
cycles, WRL# is asserted for all write operations.
†
The chip configuration register 0 (CCR0) determines whether this
pin functions as WR# or WRL#. CCR0.2 = 1 selects WR#; CCR0.2 =
0 selects WRL#.
Table 15-2. External Memory Interface Registers
Address Description
2018H
Register
Mnemonic
CCR0
Chip Configuration 0
Controls powerdown mode, bus-control signals, and internal memory
protection. Three of its bits combine with two bits of CCR1 to control wait
states and bus width.
CCR1
201AH
1FF3H
Chip Configuration 1
Enables the watchdog timer and selects the bus timing mode. Two of its bits
combine with three bits of CCR0 to control wait states and bus width.
P5_DIR
Port 5 Direction
Each bit of P5_DIR controls the direction of the corresponding pin. Clearing
a bit configures a pin as a complementary output; setting a bit configures a
pin as an input or open-drain output. (Open-drain outputs require external
pull-ups.)
P5_MODE
P5_PIN
1FF1H
1FF7H
Port 5 Mode
Each bit of P5_MODE controls whether the corresponding pin functions as a
standard I/O port pin or as a special-function signal. Setting a bit configures a
pin as a special-function signal; clearing a bit configures a pin as a standard
I/O port pin.
Port 5 Input
Each bit of P5_PIN reflects the current state of the corresponding pin,
regardless of the pin configuration.
15-4
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INTERFACING WITH EXTERNAL MEMORY
Table 15-2. External Memory Interface Registers (Continued)
Register
Mnemonic
Address
Description
P5_REG
1FF5H
Port 5 Data Output
For an input, regardless of the pin’s configuration, set the corresponding
P5_REG bit.
For an output, write the data to be driven out by each pin to the corre-
sponding bit of P5_REG. When a pin is configured as standard I/O
(P5_MODE.y = 0), the result of a CPU write to P5_REG is immediately
visible on the pin. When a pin is configured as a special-function signal
(P5_MODE.y = 1), the associated on-chip peripheral or off-chip component
controls the pin. The CPU can still write to P5_REG, but the pin is unaffected
until it is switched back to its standard I/O function.
This feature allows software to configure a pin as standard I/O (clear
P5_MODE.y), initialize or overwrite the pin value, then configure the pin as a
special-function signal (set P5_MODE.y). In this way, initialization, fault
recovery, exception handling, etc., can be done without changing the
operation of the associated peripheral.
Table 15-3. Register Settings for Configuring External Memory Interface Signals
External Memory Interface
Port Pin
Signal Type
Port Register Settings
Signal Name
P5.0
P5.1
P5.2
P5.3
P5.5
P5.6
P5.7
ALE/ADV#
O
O
O
O
O
I
P5_DIR = 110X 0000B
INST
WR#/WRL#†
P5_MODE = 111X 1111B
P5_REG = 11XX XXXXB
RD#
BHE#/WRH#†
READY
BUSWIDTH (Kx)
I
†
The chip configuration register 0 (CCR0), which is loaded at reset from the chip configuration byte 0
(CCB0, 2018H) during normal operation, determines whether P5.2 functions as BHE# or WRH# and
whether P5.5 functions as WR# or WRL#. CCR0.2 = 1 selects BHE# and WR#; CCR0.2 = 1 selects
WRH# and WRL#.
15.2 CHIP CONFIGURATION REGISTERS AND CHIP CONFIGURATION BYTES
Two chip configuration registers (CCRs) have bits that set parameters for chip operation and ex-
ternal bus cycles. The CCRs cannot be accessed by code. They are loaded from the chip config-
uration bytes (CCBs), which reside in nonvolatile memory at addresses 2018H (CCB0) and
201AH (CCB1).
15-5
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When the microcontroller returns from reset, the bus controller fetches the CCBs and loads them
into the CCRs. From this point, these CCR bit values define the chip configuration until the mi-
crocontroller is reset again. The CCR bits are described in Figures 15-1 and 15-2. (Refer to Chap-
ter 16, “Programming the Nonvolatile Memory,” for descriptions of the methods for
programming the CCBs.)
15-6
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INTERFACING WITH EXTERNAL MEMORY
no direct access†
CCR0
The chip configuration 0 (CCR0) register controls powerdown mode, bus-control signals, and internal
memory protection. Three of its bits combine with two bits of CCR1 to control wait states and bus
width.
7
0
LOC1
LOC0
IRC1
IRC0
ALE
WR
BW0
PD
Bit
Number
Bit
Mnemonic
Function
7:6
LOC1:0
Lock Bits
These two bits control read and write access to the OTPROM during
normal operation. Refer to “Controlling Access to the OTPROM During
Normal Operation” on page 16-4 for details.
LOC1 LOC0
0
0
1
1
0
1
0
1
read and write protect
read protect only
write protect only
no protection
5:4
IRC1:0
Internal Ready Control
These two bits, along with IRC2 (CCR1.1) and the READY pin determine
the number of wait states that can be inserted into the bus cycle. While
READY is held low, wait states are inserted into the bus cycle until the
programmed number of wait states is reached. If READY is pulled high
before the programmed number of wait states is reached, no additional
wait states will be inserted into the bus cycle.
IRC2 IRC1 IRC0
0
0
1
1
1
1
1
0
X
1
0
0
1
1
0
1
X
0
1
0
1
zero wait states
illegal
illegal
one wait state
two wait states
three wait states
infinite
If you choose the infinite wait states option, you must keep P5.6
configured as the READY signal. Also, be sure to add external hardware
to count wait states and pull READY high within a specified time.
Otherwise, a defective external device could tie up the address/data bus
indefinitely.
†
The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after reset, unless the
microcontroller is entering programming modes (see “Entering Programming Modes” on page 16-13),
in which case the programming chip configuration bytes (PCCBs) are used. The CCBs reside in
nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
Figure 15-1. Chip Configuration 0 (CCR0) Register
15-7
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CCR0 (Continued)
no direct access†
The chip configuration 0 (CCR0) register controls powerdown mode, bus-control signals, and internal
memory protection. Three of its bits combine with two bits of CCR1 to control wait states and bus
width.
7
0
LOC1
LOC0
IRC1
IRC0
ALE
WR
BW0
PD
Bit
Number
Bit
Mnemonic
Function
Address Valid Strobe and Write Strobe
3
ALE
These bits define which bus-control signals will be generated during
external read and write cycles.
2
WR
ALE WR
0
0
1
1
0
1
0
1
address valid with write strobe mode
(ADV#, RD#, WRL#, WRH#)
address valid strobe mode
(ADV#, RD#, WR#, BHE#)
write strobe mode
(ALE, RD#, WRL#, WRH#)
standard bus-control mode
(ALE, RD#, WR#, BHE#)
1
BW0
Buswidth Control
This bit, along with the BW1 bit (CCR1.2), selects the bus width.
BW1 BW0
0
0
1
1
0
1
0
1
illegal
16-bit only
8-bit only
BUSWIDTH pin controlled
0
PD
Powerdown Enable
Controls whether the IDLPD #2 instruction causes the microcontroller to
enter powerdown mode. If your design uses powerdown mode, set this
bit when you program the CCBs. If it does not, clearing this bit when you
program the CCBs will prevent accidental entry into powerdown mode.
0 = disable powerdown mode
1 = enable powerdown mode
†
The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after reset, unless the
microcontroller is entering programming modes (see “Entering Programming Modes” on page 16-13),
in which case the programming chip configuration bytes (PCCBs) are used. The CCBs reside in
nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
Figure 15-1. Chip Configuration 0 (CCR0) Register (Continued)
15-8
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INTERFACING WITH EXTERNAL MEMORY
no direct access†
CCR1
The chip configuration 1 (CCR1) register enables the watchdog timer and selects the bus timing
mode. Two of its bits combine with three bits of CCR0 to control wait states and bus width.
7
0
1
1
0
1
WDE
BW1
IRC2
0
Bit
Number
Bit
Mnemonic
Function
7:6
1
To guarantee proper operation, write ones to these bits.
To guarantee proper operation, write zero to this bit.
To guarantee proper operation, write one to this bit.
Watchdog Timer Enable
5
4
3
0
1
WDE
Selects whether the watchdog timer is always enabled or enabled the
first time it is cleared.
0 = always enabled
1 = enabled first time it is cleared
2
BW1
Buswidth Control
This bit, along with the BW0 bit (CCR0.1), selects the bus width.
BW1 BW0
0
0
1
1
0
1
0
1
illegal
16-bit only
8-bit only
BUSWIDTH pin controlled
†
The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after reset, unless
the microcontroller is entering programming modes (see “Entering Programming Modes” on page
16-13), in which case the programming chip configuration bytes (PCCBs) are used. The CCBs
reside in nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
Figure 15-2. Chip Configuration 1 (CCR1) Register
15-9
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CCR1 (Continued)
no direct access†
The chip configuration 1 (CCR1) register enables the watchdog timer and selects the bus timing
mode. Two of its bits combine with three bits of CCR0 to control wait states and bus width.
7
0
1
1
0
1
WDE
BW1
IRC2
0
Bit
Number
Bit
Mnemonic
Function
1
IRC2
Ready Control
This bit, along with IRC0 (CCR0.4), IRC1 (CCR0.5), and the READY pin
determine the number of wait states that can be inserted into the bus
cycle. While READY is held low, wait states are inserted into the bus
cycle until the programmed number of wait states is reached. If READY is
pulled high before the programmed number of wait states is reached, no
additional wait states will be inserted into the bus cycle.
IRC2 IRC1 IRC0
0
0
1
1
1
1
1
0
X
1
0
0
1
1
0
1
X
0
1
0
1
zero wait states
illegal
illegal
one wait state
two wait states
three wait states
infinite
If you choose the infinite wait states option, you must keep P5.6
configured as the READY signal. Also, be sure to add external hardware
to count wait states and pull READY high within a specified time.
Otherwise, a defective external device could tie up the address/data bus
indefinitely.
0
0
Reserved; for compatibility with future devices, write zero to this bit.
†
The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after reset, unless
the microcontroller is entering programming modes (see “Entering Programming Modes” on page
16-13), in which case the programming chip configuration bytes (PCCBs) are used. The CCBs
reside in nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
Figure 15-2. Chip Configuration 1 (CCR1) Register
15.3 BUS WIDTH AND MULTIPLEXING
The external bus can operate as either a 16-bit multiplexed address/data bus or as a multiplexed
16-bit address/8-bit data bus (Figure 15-3).
15-10
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INTERFACING WITH EXTERNAL MEMORY
Bus Control
Bus Control
8-bit Address
High
16-bit Multiplexed
Address/Data
AD15:8
(Port 4)
AD15:0
(Ports 4 and 3)
8-bit Multiplexed
Address/Data
AD7:0
(Port 3)
8XC196
8XC196
16-bit Bus
8-bit Bus
A3068-01
Figure 15-3. Multiplexing and Bus Width Options
After reset, but before the CCB fetch, the microcontroller is configured for 8-bit bus mode, re-
gardless of the BUSWIDTH input. The upper address lines (AD15:8) are weakly driven through-
out the CCB0 and CCB1 bus cycles. To prevent bus contention, neither pull-ups nor pull-downs
should be used on AD15:8. Also, the upper bytes of the CCB words (locations 2019H and
201BH) should be loaded with 20H. If the external memory outputs 20H on its high byte, there
will be no bus contention.
After the CCBs are loaded into the CCRs, the values of BW0 and BW1 define the data bus width
as either a fixed 8-bit, a fixed 16-bit, or a dynamic 16-bit/8-bit bus width controlled by the
BUSWIDTH signal. (The BW0 and BW1 bits are defined in Figures 15-1 and 15-2.)
If BW0 is clear and BW1 is set, the bus controller is locked into an 8-bit bus mode. In comparing
an 8-bit bus system to a 16-bit bus system, expect some performance degradation. In a 16-bit bus
system, a word fetch is done with a single word fetch. However, in an 8-bit bus system, a word
fetch takes an additional bus cycle because it must be done with two byte fetches.
If BW0 is set and BW1 is clear, the bus controller is locked into a 16-bit bus mode. If both BW0
and BW1 are set, the BUSWIDTH signal controls the bus width. The bus is 16 bits wide when
BUSWIDTH is high, and 8 bits wide when BUSWIDTH is low. The BUSWIDTH signal is sam-
pled after the address is on the bus, as shown in Figures 15-4 and 15-5.
15-11
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T
XTAL1
XTAL1
CLKOUT
†
ALE
BUSWIDTH
AD15:0
T
(min)
CLGX
Valid
T
AVGV
Data In
Address Out
† The CLKOUT pin is available only on the 8XC196MC, MD.
A3162-01
Figure 15-4. BUSWIDTH Timing Diagram (8XC196MC, MD)
T
XTAL1
XTAL1
ALE
T
AVGV
T
BUSWIDTH
AD15:0
LLGV
(max)
T
LLGX
(min)
Address Out
Data In
A3169-01
Figure 15-5. BUSWIDTH Timing Diagram (8XC196MH)
15-12
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INTERFACING WITH EXTERNAL MEMORY
.
Table 15-4. BUSWIDTH Signal Timing Definitions
Definition
Symbol
TAVGV
Address Valid to BUSWIDTH Setup
Maximum time the external device has to assert or deassert BUSWIDTH after the microcon-
troller outputs the address.
†
TCLGX
TLLGV
TLLGX
BUSWIDTH Hold after CLKOUT Low
Minimum time the level of the BUSWIDTH signal must be valid after CLKOUT falls.
††
††
ALE Low to BUSWIDTH Setup
Maximum time the external device has to assert or deassert BUSWIDTH after ALE falls.
BUSWIDTH Hold after ALE Low
Minimum time the level of the BUSWIDTH signal must be valid after ALE falls.
TXTAL1
1/FXTAL1
All AC timings are referenced to TXTAL1
.
†
This specification applies to the 8XC196MC, MD microcontrollers only.
This specification applies to the 8XC196MH microcontroller only.
††
The BUSWIDTH signal can be used in numerous applications. For example, a system could store
code in a 16-bit memory device and data in an 8-bit memory device. The BUSWIDTH signal
could be tied to the chip-select input of the 8-bit memory device (shown in Figure 15-13 on page
15-24). When BUSWIDTH is low, it enables 8-bit bus mode and selects the 8-bit memory device.
When BUSWIDTH is high, it enables 16-bit bus mode and deselects the 8-bit memory device.
15.3.1 Timing Requirements for BUSWIDTH
When using BUSWIDTH to dynamically change between 8-bit and 16-bit bus widths, setup and
hold timings must be met for proper operation (see Figures 15-4 and 15-5, and Table 15-4). Be-
cause a decoded, valid address is used to generate the BUSWIDTH signal, the setup time is spec-
ified relative to the address being valid. This specification, TAVGV, indicates how much time an
external device has to decode the valid address and generate a valid BUSWIDTH signal. As
shown in Figure 15-5, the 8XC196MH has an additional BUSWIDTH setup timing specification.
This specification, TLLGV, indicates how much time an external device has to generate a valid
BUSWIDTH signal after ALE falls.
BUSWIDTH must be held valid until the minimum hold specification, TCLGX (for 8XC196MC,
MD) or TLLGX (for 8XC196MH), has been met. Refer to the datasheet for the current TAVGV
,
TCLGX, and TLLGX specifications.
15-13
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15.3.2 16-bit Bus Timings
When the microcontroller is configured to operate in the 16-bit bus-width mode, lines AD15:0
form a 16-bit multiplexed address/data bus. Figure 15-6 shows an idealized timing diagram for
the external read and write cycles. Comprehensive timing specifications are shown in Figure
15-22 on page 15-32.
The rising edge of the address latch enable (ALE) signal indicates that the microcontroller is driv-
ing an address onto the bus (AD15:0). The microcontroller presents a valid address before ALE
falls. The ALE signal is used to strobe a transparent latch (such as a 74AC373), which captures
the address from AD15:0 and holds it while the bus controller puts data onto AD15:0.
For 16-bit read cycles, the bus controller floats the bus and then drives RD# low so that it can
receive data. The external memory must put data (Data In) onto the bus before the rising edge of
RD#. The datasheet specifies the maximum time the memory device has to output valid data after
RD# is asserted (TRLDV). When INST is asserted, it indicates that the read operation is an instruc-
tion fetch.
For 16-bit write cycles, the bus controller drives WR# low, then puts data onto the bus. The rising
edge of WR# signifies that data is valid. At this time, the external system must latch the data.
15-14
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INTERFACING WITH EXTERNAL MEMORY
XTAL1
CLKOUT
†
ALE
Valid
BUSWIDTH
AD15:0
(read)
Address Out
Data In
RD#
INST
Valid
AD15:0
(write)
Address Out
Data Out
WR#
† The CLKOUT pin is available only on the 8XC196MC, MD.
A3163-01
Figure 15-6. Timings for 16-bit Buses
15-15
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15.3.3 8-bit Bus Timings
When the microcontroller is configured to operate in the 8-bit bus mode, lines AD7:0 form a mul-
tiplexed lower address and data bus. Lines AD15:8 are not multiplexed; the upper address is
latched and remains valid throughout the bus cycle. Figure 15-7 shows an idealized timing dia-
gram for the external read and write cycles. One cycle is required for an 8-bit read or write. A 16-
bit access requires two cycles. The first cycle accesses the lower byte, and the second cycle ac-
cesses the upper byte. Except for requiring an extra cycle to write the bytes separately, the timings
are the same as on the 16-bit bus.
The ALE signal is used to demultiplex the lower address by strobing a transparent latch (such as
a 74AC373).
For 8-bit bus read cycles, after ALE falls, the bus controller floats the bus and drives the RD#
signal low. The external memory then must put its data on the bus. That data must be valid at the
rising edge of the RD# signal. To read a data word, the bus controller performs two consecutive
reads, reading the low byte first, followed by the high byte.
For 8-bit bus write cycles, after ALE falls, the bus controller outputs data on AD7:0 and then
drives WR# low. The external memory must latch the data by the time WR# goes high. That data
will be valid on the bus until slightly after WR# goes high. To write a data word, the bus controller
performs two consecutive writes, writing the low byte first, followed by the high byte.
15-16
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INTERFACING WITH EXTERNAL MEMORY
XTAL1
CLKOUT
†
ALE
BUSWIDTH
AD15:8
Address Out
Low data in
Address Out
AD7:0
(read)
Address
Out
Address
High data in
+1 Out
RD#
INST
AD7:0
(write)
Address
Out
Address
Low data out
High data out
+1 Out
WR#
† The CLKOUT pin is available only on the 8XC196MC, MD.
A3164-01
Figure 15-7. Timings for 8-bit Buses
15.4 WAIT STATES (READY CONTROL)
An external device can use the READY input to lengthen an external bus cycle. When an external
address is placed on the bus, the external device can pull the READY signal low to indicate it is
not ready. In response, the microcontroller inserts wait states to lengthen the bus cycle until the
external device raises the READY signal. Each wait state adds one state time (2TXTAL1) to the bus
cycle.
After reset and until CCB1 is fetched, the bus controller always inserts three wait states into bus
cycles. Then, until P5.6 has been configured to operate as the READY signal, the internal ready
control bits (IRC2:0) control the wait states.
15-17
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After the CCB1 fetch, the internal ready control circuitry allows slow external memory devices
to increase the length of the read and write bus cycles. If the external memory device is not ready
for access, it pulls the READY signal low and holds it low until it is ready to complete the oper-
ation, at which time it releases READY. While READY is low, the bus controller inserts wait
states into the bus cycle.
The internal ready control bits, CCR0.5, CCR0.4, and CCR1.1 shown in Figures 15-1 and 15-2,
define the maximum number of wait states (0, 1, 2, 3, or infinite) that will be inserted into the bus
cycle. While READY is low, wait states are inserted into the bus cycle until the programmed
number of wait states is reached. If READY is pulled high before the programmed number of wait
states is reached, no additional wait states will be inserted into the bus cycle.
If you choose the infinite wait states option, you must keep P5.6 configured as the READY signal.
Also, be sure to add external hardware to count wait states and pull READY high within a spec-
ified time. Otherwise, a defective external device could tie up the address/data bus indefinitely.
Setup and hold timings must be met when using the READY signal to insert wait states into a bus
cycle (see Figures 15-8 and 15-9, and Table 15-5). Because a decoded, valid address is used to
generate the READY signal, the setup time is specified relative to the address being valid. This
specification, TAVYV, indicates how much time the external device has to decode the address and
assert READY after the address is valid. As shown in Figure 15-9, the 8XC196MH has an addi-
tional READY setup timing specification. This specification, TLLYV, indicates how much time an
external device has to deassert the READY signal after ALE falls.
The READY signal must be held low until the minimum TCLYX timing specification is met. Do
not exceed the maximum TCLYX or TLLYX specification or additional (unwanted) wait states might
be added. Refer to the datasheets for the current TAVYV , TCLYX, and TLLYX specifications.
15-18
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CLKOUT
†
TCLYX
(max)
ALE
READY
RD#
T
CLYX (min)
TAVYV
Address Out
Data
AD15:0
(read)
WR#
AD15:0
(write)
Address
Address Out
Data Out
† The CLKOUT pin is available only on the 8XC196MC, MD.
A3165-01
Figure 15-8. READY Timing Diagram — One Wait State (8XC196MC, MD)
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T
XTAL1
XTAL1
T
+ 2T
XTAL1
LHLH
ALE
T
LLYX (max)
T
LLYX (min)
T
LLYV
READY
RD#
16 MHz
8 MHz
T
T
+ 2T
RLRH XTAL1
AVYV
T
+ 2T
XTAL1
RLDV
T
+ 2T
AVDV
XTAL1
AD15:0
(read)
Address Out
Data In
T
+ 2T
WLWH
XTAL1
WR#
T
+ 2T
RLDV
T
XTAL1
+ 2T
QVWH
XTAL1
AD15:0
(write)
Address Out
Data Out
Address
A3167-01
Figure 15-9. READY Timing Diagram — One Wait State (8XC196MH)
Table 15-5. READY Signal Timing Definitions
Definition
Symbol
TAVYV
Address Valid to READY Setup
Maximum time the external device has to deassert READY after the microcontroller outputs
the address to guarantee that at least one wait state will occur.
†
TCLYX
READY Hold after CLKOUT Low
Minimum time the level of the READY signal must be valid after CLKOUT falls.
TLHLH
ALE Cycle Time
Minimum time between ALE pulses.
†
This specification applies to the 8XC196MC, MD microcontrollers only.
This specification applies to the 8XC196MH microcontroller only.
††
15-20
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INTERFACING WITH EXTERNAL MEMORY
Table 15-5. READY Signal Timing Definitions (Continued)
Definition
Symbol
††
TLLYX
READY Hold after ALE Low
Minimum time the level of the READY signal must be valid after ALE falls. If the maximum
value is exceeded, additional wait states will occur.
††
TLLYV
ALE Low to READY Setup
Maximum time the external device has to deassert READY after ALE falls.
TQVWH
Data Valid to WR# High
Time between data being valid on the bus and the microcontroller deasserting WR#.
TRLDV
RD# Low to Input Data Valid
Maximum time the memory system has to output valid data after the microcontroller asserts
RD#.
TRLRH
RD# Low to RD# High
RD# pulse width.
TWLWH
WR# Low to WR# High
WR# pulse width.
TXTAL1
1/FXTAL1
All AC timings are referenced to TXTAL1
.
†
This specification applies to the 8XC196MC, MD microcontrollers only.
This specification applies to the 8XC196MH microcontroller only.
††
15.5 BUS-CONTROL MODES
The ALE and WR bits (CCR0.3 and CCR0.2) define which bus-control signals will be generated
during external read and write cycles. Table 15-6 lists the four bus-control modes and shows the
CCR0.3 and CCR0.2 settings for each.
.
Table 15-6. Bus-control Modes
CCR0.3
(ALE)
CCR0.2
(WR)
Bus-control Mode
Bus-control Signals
Standard Bus-control Mode
Write Strobe Mode
ALE, RD#, WR#, BHE#
ALE, RD#, WRL#, WRH#
ADV#, RD#, WR#, BHE#
ADV#, RD#, WRL#, WRH#
1
1
0
0
1
0
1
0
Address Valid Strobe Mode
Address Valid with Write Strobe Mode
15-21
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15.5.1 Standard Bus-control Mode
In the standard bus-control mode, the microcontroller generates the standard bus-control signals:
ALE, RD#, WR#, and BHE# (see Figure 15-10). ALE is asserted while the address is driven, and
it can be used to latch the address externally. RD# is asserted for every external memory read, and
WR# is asserted for every external memory write. When asserted, BHE# selects the bank of mem-
ory that is addressed by the high byte of the data bus.
ALE
WR# or RD#
BHE#
ALE
WR# or RD#
AD7:0
Valid
Addr Low
Data Out
AD15:0
AD15:8
Address High
8-bit Bus Cycle
Addr
Data Out
16-bit Bus Cycle
A3077-01
Figure 15-10. Standard Bus Control
When the microcontroller is configured to use a 16-bit bus, separate low- and high-byte write sig-
nals must be generated for single-byte writes. Figure 15-11 shows a sample circuit that combines
BHE# and AD0 to produce these signals (WRL# and WRH#). A similar pair of signals for read
is unnecessary. For a single-byte read with the 16-bit bus, both bytes are placed on the data bus
and the processor discards the unwanted byte.
BHE#
WRH#
WR#
WRL#
74AC
373
A0
AD0
A3109-03
Figure 15-11. Decoding WRL# and WRH#
15-22
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INTERFACING WITH EXTERNAL MEMORY
Figure 15-12 shows an 8-bit system with both flash and RAM. The flash is the lower half of mem-
ory, and the RAM is the upper half. This system configuration uses the most-significant address
bit (AD15) as the chip-select signal and ALE as the address-latch signal.
CS#
CS#
AD15
AD14:8
A14:8
D7:0
A12:8
D7:0
32K×8
Flash
8K×8
RAM
8XC196
(28F256)
A7:0
74AC
373
A7:0
A7:0
AD7:0
ALE
LE
OE#
OE#
WE#
RD#
WR#
A3140-01
Figure 15-12. 8-bit System with Flash and RAM
15-23
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Figure 15-13 shows a system that uses the dynamic bus-width feature. (The CCR bits, BW0 and
BW1, are set.) Code is executed from the two EPROMs and data is stored in the byte-wide RAM.
The RAM is in high memory. It is selected by driving AD15 high, which also selects the 8-bit
bus-width mode by driving the BUSWIDTH signal low.
BUSWIDTH
CS#
CS#
CS#
A15
A14:8
A14:8
A12:8
74AC
373
A13:7
D15:8
A13:7
A12:8
AD15:8
ALE
LE
D7:0
D7:0
16K×8
EPROM
(High)
16K×8
EPROM
(Low)
8K×8
RAM
8XC196
LE
A7:1
A7:1
A7:0
74AC
373
A6:0
A6:0
A7:0
AD7:0
OE#
OE#
OE#
WE#
RD#
WR#
A3087-01
Figure 15-13. 16-bit System with Dynamic Bus Width
15-24
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INTERFACING WITH EXTERNAL MEMORY
15.5.2 Write Strobe Mode
The write strobe mode eliminates the need to externally decode high- and low-byte writes to an
external 16-bit RAM or flash device in 16-bit bus mode. When the write strobe mode is selected,
the microcontroller generates WRL# and WRH# instead of WR# and BHE#. WRL# is asserted
for all low byte writes (even addresses) and all word writes. WRH# is asserted for all high byte
writes (odd addresses) and all word writes. In the 8-bit bus mode, WRH# and WRL# are asserted
for both even and odd addresses. Figure 15-14 shows write strobe mode timing.
ALE
WRL#
WRH#
ALE
WRL# and WRH#
AD7:0
Valid
Valid
Address Low
Data Out
AD15:0
AD15:8
Address High
8-bit Bus Cycle
Address
Data Out
16-bit Bus Cycle
A3089-01
Figure 15-14. Write Strobe Mode
15-25
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Figure 15-15 shows a 16-bit system with two EPROMs and two RAMs. It is configured to use
the write strobe mode. ALE latches the address; AD15 is the chip-select signal for the memory
devices. WRL# is asserted during low byte writes and word writes. WRH# is asserted during high
byte writes and word writes. Note that the RAM devices do not use AD0. WRL# and WRH# de-
termine whether the low byte (AD0=0) or high byte (AD0=1) is selected.
V
CC
BUSWIDTH
AD15:8
CS#
CS#
CS#
CS#
A15
74AC
373
A14:8
A13:7
A12:7
D15:8
A12:7
A13:7
LE
D15:8
ALE
16K×8
EPROM
(High)
16K×8
EPROM
(Low)
8K×8
8K×8
RAM
(Low)
RAM
8XC196
(High)
D7:0
D7:0
LE
A7:1
AD7:0
74AC
373
A6:0
OE#
A6:0
OE#
A6:0
OE# WE#
A6:0
WE#
OE#
RD#
WRH#
WRL#
A3090-01
Figure 15-15. 16-bit System with Writes to Byte-wide RAMs
15-26
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INTERFACING WITH EXTERNAL MEMORY
15.5.3 Address Valid Strobe Mode
When the address valid strobe mode is selected, the microcontroller generates the address valid
signal (ADV#) instead of the address latch enable signal (ALE). ADV# is asserted after an exter-
nal address is valid (see Figure 15-16). This signal can be used to latch the valid address and si-
multaneously enable an external memory device. (See the examples in Figures 15-18 and 15-19.)
ADV#
ADV#
WR# or RD#
WR# or RD#
Addr
Low
Data Out
Valid
BHE#
AD7:0
Address
Data Out
Address High
AD15:0
AD15:8
16-bit Bus Cycle
8-bit Bus Cycle
A3092-02
Figure 15-16. Address Valid Strobe Mode
The difference between ALE and ADV# is that ADV# is asserted for the entire bus cycle, not just
to latch the address. Figure 15-17 shows the difference between ALE and ADV# for a single read
or write cycle. Note that for back-to-back bus access, the ADV# function will look identical to
the ALE function. The difference becomes apparent only when the bus is idle. Because ADV# is
high during these periods, external memory will be disabled, thus saving power.
AD15:0
ADV#
Address
Data
ALE
RD#, WR#
Next Bus Cycle
Bus Idle
A3093-02
Figure 15-17. Comparison of ALE and ADV# Bus Cycles
15-27
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Figure 15-18 and Figure 15-19 show sample circuits that use the address valid strobe mode. Fig-
ure 15-18 shows a simple 8-bit system with a single flash. It is configured for the address valid
strobe mode. This system configuration uses the ADV# signal as both the flash chip-select signal
and the address-latch signal.
RD#
OE#
A14:8
AD14:8
D7:0
32K×8
Flash
8XC196
(28F256)
A7:0
74AC
373
A7:0
CS#
AD7:0
LE
ADV#
A3094-01
Figure 15-18. 8-bit System with Flash
15-28
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INTERFACING WITH EXTERNAL MEMORY
Figure 15-19 shows a 16-bit system with two EPROMs. This system configuration uses the
ADV# signal as both the EPROM chip-select signal and the address-latch signal.
V
CC
BUSWIDTH
AD15:8
CS#
CS#
A14:8
A15:8
74AC
373
A13:7
D15:8
A13:7
LE
ADV#
8XC196
AD7:0
D7:0
A6:0
16K×8
EPROM
(Low)
16K×8
EPROM
(High)
LE
A7:1
A7:1
74AC
373
A6:0
OE#
OE#
RD#
A3095-01
Figure 15-19. 16-bit System with EPROM
15-29
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15.5.4 Address Valid with Write Strobe Mode
When the address valid with write strobe mode is selected, the microcontroller generates the
ADV#, RD#, WRL#, and WRH# bus-control signals. This mode is used for a simple system us-
ing an external 16-bit data bus. Figure 15-20 shows the timing. The RD# signal (not shown) is
similar to WRL# and WRH#. The example system of Figure 15-21 uses address valid with write
strobe to access byte-wide RAMs with a 16-bit data bus.
ADV#
WRL#
ADV#
WRL#
Valid
Addr
Low
Data Out
Valid
WRH#
AD7:0
Address
Data Out
Address High
8-bit Bus Cycle
AD15:0
AD15:8
16-bit Bus Cycle
A3096-02
Figure 15-20. Timings of Address Valid with Write Strobe Mode
15-30
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INTERFACING WITH EXTERNAL MEMORY
V
CC
BUSWIDTH
AD15:8
CS#
CS#
A13:8
74AC
373
A12:7
D15:8
A12:7
LE
ADV#
D7:0
A6:0
8K×8
RAM
(High)
8K×8
RAM
(Low)
8XC196
LE
A7:1
74AC
373
AD7:0
A6:0
WE#
WE#
WRH#
WRL#
A3097-01
Figure 15-21. 16-bit System with RAM
15.6 SYSTEM BUS AC TIMING SPECIFICATIONS
Refer to the latest datasheet for the AC timings to make sure your system meets specifications.
The major external bus timing specifications are shown in Figure 15-22.
15-31
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T
XTAL1
XTAL1
T
T
CHCL
T
CLCL
XHCH
CLKOUT
†
T
T
LLCH
CLLH
T
LHLH
ALE/ADV#
T
LHLL
T
RHLH
T
T
LLRL
RLRH
RD#
T
T
RHDZ
RLAZ
T
AVLL
T
T
RLDV
T
LLAX
Address Out
Data In
AD15:0
(read)
T
AVDV
T
T
LLWL
WHLH
WLWH
WR#
T
T
WHQX
QVWH
Data Out
AD15:0
(write)
Address Out
Address Out
T
T
, T
WHBX RHBX
Valid
BHE#, INST
, T
WHAX RHAX
AD15:8
(8-bit mode)
Address Out
† The CLKOUT pin is available only on the 8XC196MC, MD.
A3166-01
Figure 15-22. System Bus Timing
15-32
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INTERFACING WITH EXTERNAL MEMORY
15.6.1 Explanation of AC Symbols
Each symbol consists of two pairs of letters prefixed by “T” (for time). The characters in a pair
indicate a signal and its condition, respectively. Symbols represent the time between the two sig-
nal/condition points. For example, TLLRL is the time between signal L (ALE/ADV#) condition L
(Low), and signal R (RD#) condition L (Low). Table 15-7 defines the signal and condition codes.
Table 15-7. AC Timing Symbol Definitions
Signals
Conditions
A
Address
Q
R
W
X
Output Data
RD#
H
L
High
B
BHE#
Low
C†
D
G
CLKOUT
Input Data
BUSWIDTH
ALE/ADV#
WR#, WRH#, WRL#
XTAL1
V
X
Z
Valid
No Longer Valid
Floating
Y
READY
L
†
The CLKOUT pin is available only on the 8XC196MC, MD microcontrollers.
15.6.2 AC Timing Definitions
Tables 15-8 and 15-9 define the AC timing specifications that the memory system must meet and
those that the microcontroller will provide.
Table 15-8. External Memory Systems Must Meet These Specifications
Symbol
Definition
TAVDV
Address Valid to Input Data Valid
Maximum time the memory system has to output valid data after the microcontroller outputs a
valid address.
TRHDZ
RD# High to Input Data Float
Time after the microcontroller deasserts RD# until the memory system must float the bus. If this
timing is not met, bus contention will occur.
TRLDV
RD# Low to Input Data Valid
Maximum time the memory system has to output valid data after the microcontroller asserts
RD#.
†
The CLKOUT pin is available only on the 8XC196MC, MD microcontrollers.
15-33
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Table 15-9. Microcontroller Meets These Specifications
Definition
Symbol
TAVLL
Address Setup to ALE/ADV# Low
Length of time address is valid before ALE/ADV# falls. Useful when using an external latch to
demultiplex the address from the address data bus.
†
TCHCL
CLKOUT High CLKOUT Low
CLKOUT pulse width. Useful when using CLKOUT to clock external devices.
†
TCLCL
CLKOUT Cycle Time
The period of the CLKOUT signal; equal to 2TXTAL1
.
†
TCLLH
CLKOUT Low to ALE/ADV# High
TLHLH
ALE Cycle Time
Minimum time between two ALE rising edges.
TLHLL
ALE High to ALE Low
ALE pulse width. Useful when using an external latch to demultiplex the address from the
address data bus.
TLLAX
AD15:0 Hold after ALE/ADV# Low
Length of time address is valid after ALE/ADV# falls. Useful when using an external latch to
demultiplex the address from the address data bus.
†
TLLCH
ALE/ADV# Low to CLKOUT High
ALE/ADV# Low to RD# Low
TLLRL
Length of time after ALE/ADV# falls before the microcontroller asserts RD#. Maximum time a
memory system has to decode the address before the microcontroller asserts RD#.
TLLWL
ALE/ADV# Low to WR# Low
Length of time after ALE/ADV# falls before the microcontroller asserts WR#. Maximum time a
memory system has to decode the address before the microcontroller asserts WR#.
TQVWH
Output Data Valid to WR# High
Length of time output data is valid before the microcontroller deasserts WR#.
TRHAX
Address (high byte) Hold after RD# High
Minimum time the high byte of the address (when using an 8-bit data bus) is valid after the
microcontroller deasserts RD#.
TRHBX
BHE#, INST Hold after RD# High
Minimum time these signals are valid after the microcontroller deasserts RD#.
TRHLH
RD# High to ALE High
Time between the microcontroller deasserting RD# and the next ALE pulse. Maximum time the
memory system has to put data on the bus before the next address cycle.
TRLAZ
RD# Low to Address Float
Time after the microcontroller deasserts RD# until it stops driving the address on the bus.
TRLRH
RD# Low to RD# High
RD# pulse width.
†
The CLKOUT pin is available only on the 8XC196MC, MD microcontrollers.
15-34
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INTERFACING WITH EXTERNAL MEMORY
Table 15-9. Microcontroller Meets These Specifications (Continued)
Definition
Symbol
TWHAX
Address (high byte) Hold after WR# High
Minimum time the high byte of the address (when using an 8-bit data bus) is valid after the
microcontroller deasserts WR#.
TWHBX
BHE#, INST Hold after WR# High
Minimum time these signals are valid after the microcontroller deasserts WR#.
TWHLH
WR# High to ALE High
Time between the microcontroller deasserting WR# and next ALE pulse. Maximum time the
memory system has to get data off the bus before the next address cycle.
TWHQX
Output Data Hold after WR# High
Length of time output data is valid on the bus after the microcontroller deasserts WR#.
TWLWH
WR# Low to WR# High
WR# pulse width.
†
TXHCH
XTAL1 High to CLKOUT High or Low
TXTAL1
1/FXTAL1
The period of the frequency on the XTAL1 input (FXTAL1). All AC timings are referenced to
TXTAL1
.
†
The CLKOUT pin is available only on the 8XC196MC, MD microcontrollers.
15-35
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16
Programming the
Nonvolatile Memory
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CHAPTER 16
PROGRAMMING THE NONVOLATILE MEMORY
The 87C196MC and 87C196MD contain 16 Kbytes of one-time-programmable read-only mem-
ory (OTPROM); the 87C196MH contains 32 Kbytes. OTPROM is similar to EPROM, but it
comes in an unwindowed package and cannot be erased. You can either program the OTPROM
yourself or have the factory program it as a quick-turn ROM product (this option may not be
available for all devices). This chapter provides procedures and guidelines to help you program
the device. The information is organized as follows.
• overview of programming methods
• OTPROM memory map (page 16-2)
• security features (page 16-3)
• programming pulse width (page 16-8)
• modified quick-pulse algorithm (page 16-9)
• programming mode pins (page 16-11)
• entering programming modes (page 16-13)
• slave programming (page 16-15)
• auto programming (page 16-25)
• PCCB and UPROM programming (8XC196MH only; page 16-30)
• run-time programming (page 16-32)
16.1 PROGRAMMING METHODS
You can program the OTPROM by configuring a circuit that allows the device to enter a program-
ming mode. In programming modes, the device executes an algorithm that resides in the internal
test ROM.
• Slave programming mode allows you to use an EPROM programmer as a master to
program several microcontrollers (the slaves). The code and data to be programmed into the
nonvolatile memory typically resides on a diskette. The EPROM programmer transfers the
code and data from the diskette to its memory, then manipulates the slave’s pins to define
the addresses to be programmed and the contents to be written to those addresses. Using this
16-1
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mode, you can program and verify single or multiple words in the OTPROM. This mode
allows you to read the signature word and programming voltages and to program the
PCCBs and unerasable PROM (UPROM) bits. Programming vendors and Intel distributors
typically use this mode to program a large number of microcontrollers with a customer’s
code and data.
• Auto programming mode enables the microcontroller to act as a master to program itself
with code and data that reside in an external memory device. Using this mode, you can
program the entire OTPROM array except the UPROM bits and PCCBs. (For the
8XC196MH, PCCB and UPROM modes allow you to program those locations. For the
8XC196MC and 8XC196MD, only slave mode allows you to program them.) After
programming, you can use the ROM-dump mode to write the entire OTPROM array to an
external memory device to verify its contents. Customers typically use this low-cost method
to program a small number of microcontrollers after development and testing are complete.
You can also program individual OTPROM locations without entering a programming mode.
With this method, called run-time programming, your software controls the number and duration
of programming pulses. Customers typically use this mode to download small sections of code to
the microcontroller during software development and testing.
16.2 OTPROM MEMORY MAP
The OTPROM contains customer-specified special-purpose and program memory (Table 16-1).
The 128-byte special-purpose memory partition is used for interrupt vectors, the chip configura-
tion bytes (CCBs), and the security key. Several locations are reserved for testing or for use in
future products. Write the value (20H or FFH) indicated in Table 16-1 to each reserved location.
The remainder of the OTPROM is available for code storage.
16-2
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PROGRAMMING THE NONVOLATILE MEMORY
Table 16-1. 87C196Mx OTPROM Memory Map
Address Range
(Hex)
Description
9FFF (MH)
2080
Program memory
Program memory
5FFF (MC, MD)
2080
207F
205E
Reserved (each location must contain FFH)
PTS vectors
205D
2040
203F
2030
Upper interrupt vectors
202F
2020
Security key
201F
201C
Reserved (each location must contain FFH)
201B
201A
2019
2018
Reserved (must contain 20H)
CCB1
Reserved (must contain 20H)
CCB0
2017
2014
Reserved (each location must contain FFH)
Lower interrupt vectors
2013
2000
16.3 SECURITY FEATURES
Several security features enable you to control access to both internal and external memory. Read
and write protection bits in the chip configuration register (CCR0), combined with a security key,
allow various levels of internal memory protection. Two UPROM bits disable fetches of instruc-
tions and data from external memory. (See Figure 16-1 on page 16-7 for more information.)
16.3.1 Controlling Access to Internal Memory
The lock bits in the chip configuration register (CCR0) control access to the OTPROM. The reset
sequence loads the CCRs from the CCBs for normal operation and from the PCCBs when enter-
ing programming modes. You can program the CCBs using any of the programming methods, but
only slave and PCCB programming modes allow you to program the PCCBs.
NOTE
The developers have made a substantial effort to provide an adequate program
protection scheme. However, Intel cannot and does not guarantee that these
protection methods will always prevent unauthorized access.
16-3
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16.3.1.1
Controlling Access to the OTPROM During Normal Operation
During normal operation, the lock bits in CCB0 control read and write accesses to the OTPROM.
Table 16-2 describes the options. You can program the CCBs using any of the programming
methods.
Table 16-2. Memory Protection for Normal Operating Mode
Read Protect
LOC1 (CCR0.7) LOC0 (CCR0.6)
Write Protect
Protection Status
No protection. Run-time programming is permitted, and the entire
OTPROM array can be read.
1
1
1
0
Write protection only. Run-time programming is disabled, but the
entire OTPROM array can be read.
Read protection. Run-time programming is disabled. If program
execution is external, only the interrupt vectors and CCBs can be
read. The security key is write protected.
0
0
1
0
Read and write protection. Run-time programming is disabled. If
program execution is external, only the interrupt vectors and CCBs
can be read.
Clearing CCB0.6 enables write protection. With write protection enabled, a write attempt causes
the bus controller to cycle through the write sequence, but it does not enable VPP or write data to
the OTPROM. This protects the entire OTPROM array from inadvertent or unauthorized pro-
gramming.
Clearing CCB0.7 enables read protection and also write protects the security key to protect it
from being overwritten. With read protection enabled, the bus controller will not read from pro-
tected areas of OTPROM. An attempt to load the slave program counter with an external address
causes the device to reset itself. Because the slave program counter can be as much as four bytes
ahead of the CPU program counter, the bus controller might prevent code execution from the last
four bytes of internal memory. The interrupt vectors and CCBs are not read protected because
interrupts can occur even when executing from external memory.
16.3.1.2
Controlling Access to the OTPROM During Programming Modes
For programming modes, three levels of protection are available:
• prohibit all programming
• prohibit all programming, but permit authorized ROM dumps
• permit authorized ROM dumps, auto programming, and slave programming
16-4
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PROGRAMMING THE NONVOLATILE MEMORY
These protection levels are provided by the PCCB0 lock bits, the CCB0 lock bits, and the internal
security key (Table 16-3). When entering programming modes, the reset sequence loads the
PCCBs into the chip configuration registers. It also loads CCB0 into internal RAM to provide an
additional level of security.
You can program the CCBs using any of the programming methods, but only slave and PCCB
programming modes permits access to the PCCBs, and only slave and auto programming allow
you to program the internal security key.
Table 16-3. Memory Protection Options for Programming Modes
LOC1
(CCR0.7)
LOC0
(CCR0.6)
Security Key
Programmed
?
Protection Status
PCCB CCB PCCB CCB
1
1
1
1
0
1
No
No protection. All programming modes allowed.
All programming disabled. ROM-dump permitted with
matching security key.
X
X
Yes
Auto and slave programming permitted with matching
security key.
1
0
0
1
0
0
Yes
X
X
X
All programming unconditionally disabled.
If you want to prohibit all programming, clear both PCCB0 lock bits. If these bits are cleared,
they prevent the device from entering any programming mode.
If you want to prevent programming, but allow ROM dumps, leave the PCCB0 read-protection
bit (PCCB0.7) unprogrammed and clear the PCCB0 write-protection bit (PCCB0.6). To protect
against unauthorized reads, program an internal security key. The ROM-dump mode compares
the internal security key location with an externally supplied security key, regardless of the CCB0
lock bits. If the security keys match, the routine continues; otherwise, the device enters an endless
internal loop.
If you want to allow slave and auto programming as well as ROM dumps, leave both PCCB0 lock
bits unprogrammed. To protect against unauthorized programming, clear the CCB0 lock bits and
program an internal security key. After the device enters either slave or auto programming mode,
the corresponding test ROM routine reads the CCB0 lock bits. If either CCB0 lock bit is enabled,
the routine compares the internal security key location with an externally supplied security key.
If the security keys match, the routine continues; otherwise, the device enters an endless internal
loop.
16-5
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You can program the internal security key in either auto or slave programming mode. Once the
security key is programmed, you must provide a matching key to gain access to any programming
mode. For auto programming and ROM-dump modes, a matching security key must reside in ex-
ternal memory. For slave programming mode, you must “program” a matching security key into
the appropriate OTPROM locations with the program word command. The locations are not ac-
tually programmed, but the data is compared to the internal security key.
WARNING
If you leave the internal security key locations unprogrammed (filled with
FFFFH), an unauthorized person could gain access to the OTPROM by using
an external EPROM with an unprogrammed external security key location or
by using slave programming mode.
16.3.2 Controlling Fetches from External Memory
Two UPROM bits disable external instruction fetches and external data fetches. If you program
the UPROM bits, an attempt to fetch data or instructions from external memory causes a device
reset. You can program the UPROM bits using slave or UPROM (8XC196MH only) program-
ming mode.
Programming the DEI bit prevents the bus controller from executing external instruction fetches.
An attempt to load the slave program counter with an external address causes the device to reset
itself. Because the slave program counter can be as much as four bytes ahead of the CPU program
counter, the bus controller might prevent code execution from the last four bytes of internal mem-
ory. The automatic reset also gives extra protection against runaway code.
Programming the DED bit prevents the bus controller from executing external data reads and
writes. An attempt to access data through the bus controller causes the device to reset itself. Set-
ting this bit disables ROM-dump mode.
To program these bits, write the correct value to the location shown in Table 16-4 using slave pro-
gramming mode. During normal operation, you can determine the values of these bits by reading
the UPROM special-function register (Figure 16-1).
16-6
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PROGRAMMING THE NONVOLATILE MEMORY
Address:
Reset State (MC, MD):
Reset State (MH):
1FF6H
02H
XXH
USFR
The unerasable PROM (USFR) register contains two bits that disable external fetches of data and
instructions and another that detects a failed oscillator. These bits can be programmed, but cannot be
erased.
WARNING: These bits can be programmed, but can never be erased. Programming these bits makes
dynamic failure analysis impossible. For this reason, devices with programmed UPROM bits cannot
be returned to Intel for failure analysis.
7
0
—
—
—
—
DEI
DED
—
—
Bit
Number
Bit
Mnemonic
Function
7:4
—
Reserved; for compatibility with future devices, write zeros to these bits.
Disable External Instruction Fetch
3
DEI
DED
—
Setting this bit prevents the bus controller from executing external
instruction fetches. Any attempt to load an external address initiates a
reset.
2
Disable External Data Fetch
Setting this bit prevents the bus controller from executing external data
reads and writes. Any attempt to access data through the bus controller
initiates a reset.
1:0
Reserved; for compatibility with future devices, write zero to these bits.
Figure 16-1. Unerasable PROM (USFR) Register
You can verify a UPROM bit to make sure it programmed, but you cannot erase it. For this reason,
Intel cannot test the bits before shipment. However, Intel does test the features that the UPROM
bits enable, so the only undetectable defects are (unlikely) defects within the UPROM cells them-
selves.
Table 16-4. UPROM Programming Values and Locations for Slave Mode
To set this bit
Write this value
To this location
DEI
08H
04H
0718H
0758H
DED
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16.4 PROGRAMMING PULSE WIDTH
The programming pulse width is controlled in different ways, depending on the programming
mode. In slave programming mode, the pulse width is controlled by the PALE# signal. In auto
programming mode, it is loaded from the external EPROM into the PPW register. In the UPROM
(8XC196MH only) and PCCB programming modes, the pulse width is controlled by the test-
ROM routine. (For run-time programming, your software controls the pulse width.)
To determine the correct PPW_VALUE for the frequency of the device, use the following formula
and round the result to the next higher integer.
PPW_VALUE for 8XC196MC, MD = 62.5 × FXTAL1
PPW_VALUE for 8XC196MH
= 25 × FXTAL1
where:
PPW_VALUE
FXTAL1
is a 16-bit word
is the input frequency on XTAL1, in MHz
no direct access
PPW
The programming pulse width (PPW) register is loaded from the external EPROM (locations 14H and
15H for the 8XC196MC and MD; locations 4014H and 4015H for the 8XC196MH) in auto programming
mode. The PPW_VALUE determines the programming pulse width.
15
PPW15
8
PPW14
PPW6
PPW13
PPW5
PPW12
PPW4
PPW11
PPW3
PPW10
PPW2
PPW9
PPW1
PPW8
PPW0
7
0
PPW7
Bit
Bit
Function
Number Mnemonic
15:0 PPW15:0
PPW_VALUE
This value establishes the programming pulse width for auto programming.
Use the appropriate formula to calculate the PPW_VALUE, then write the
result to the PPW register. (Table 16-5 shows the calculations and results for
8 MHz and 16 MHz operation.)
PPW_VALUE for 8XC196MC, MD = 62.5 ×FXTAL1
PPW_VALUE for 8XC196MH
= 25 ×FXTAL1
Figure 16-2. Programming Pulse Width (PPW) Register
The examples in Table 16-5 calculate the required minimum pulse width (100 µs for the
8XC196MH and 250 µs for the 8XC196MC, MD) for an 8-MHz and a 16-MHz crystal.
16-8
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PROGRAMMING THE NONVOLATILE MEMORY
Table 16-5. Example PPW_VALUE Calculations
8XC196MC, MD
(Two 250-µs pulses required)
8XC196MH
(Five 100-µs pulses required)
FXTAL1
8 MHz PPW_VALUE = 62.5 × 8 = 504 = 01F4H
PPW_VALUE = 25 × 8 = 200 = 00C8H
16 MHz PPW_VALUE = 62.5 × 16 = 1000 = 03F8H PPW_VALUE = 25 × 16 = 400 = 0190H
16.5 MODIFIED QUICK-PULSE ALGORITHM
Both the slave and auto programming routines use the modified quick-pulse algorithm (Figure
16-3). The modified quick-pulse algorithm sends programming pulses to each OTPROM word
location. After the required number of programming pulses, a verification routine compares the
contents of the programmed location to the input data. A verification error deasserts the PVER
signal, but does not stop the programming routine. This process repeats until each OTPROM
word has been programmed and verified. Intel guarantees lifetime data retention for a device pro-
grammed with the modified quick-pulse algorithm.
NOTE
The 87C196MC, MD devices use two pulses; the 87C196MH uses five.
16-9
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From Auto or Slave
Programming
Start PPW Timer
Write Data to
OTPROM
Enable Interrupts
Enter Idle Mode
Wait for PPW Timer Interrupt
No
Required
Writes Done
?
Yes
Compare Programmed
Locations and Set Flags
Return
A0190-03
Figure 16-3. Modified Quick-pulse Algorithm
Auto programming repeats the pulse twice (for the 87C196MC, MD) or five times (for the
87C196MH), using the pulse width you specify in the external EPROM. Slave mode repeats the
pulse until PROG# is deasserted. In slave programming mode, the PALE# signal controls the
pulse width. In all cases, the pulse width must be at least 100 µs for successful programming.
16-10
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PROGRAMMING THE NONVOLATILE MEMORY
16.6 PROGRAMMING MODE PINS
Figure 16-4 illustrates the signals used in programming and Table 16-6 describes them. The EA#,
VPP, and PMODE pins combine to control entry into programming modes. You must configure
the PMODE (P0.7:4) pins to select the desired programming mode (see Table 16-7 on page
16-13). Each programming routine configures the port 2 pins to operate as the appropriate spe-
cial-function signals. Ports 3 and 4 automatically serve as the PBUS during programming.
V
EA#
Programming
Voltage
P4.7:0
P3.7:0
PP
PBUS
4
PMODE.3:0
P0.7:4
P2.7
P2.6
P2.4
P2.2
P2.1
P2.0
PACT#
CPVER
AINC#
PROG#
PALE#
PVER
8XC196 Device
A2839-02
Figure 16-4. Pin Functions in Programming Modes
Table 16-6. Pin Descriptions
Special-
function
Signal
Program-
ming
Mode
Port Pin
Type
Description
P0.7:4
PMODE.3:
PMODE.0
I
All
Programming Mode Select
Determines the programming mode. PMODE is
sampled after a device reset and must be static
while the part is operating. (Table 16-7 on page
16-13 lists the PMODE values and programming
modes.)
P2.0
P2.1
PVER
O
Slave
Auto
Programming Verification
During slave or auto programming, PVER is
updated after each programming pulse. A high
output signal indicates successful programming of a
location, while a low signal indicates a detected
error.
PALE#
I
Slave
Programming ALE Input
During slave programming, a falling edge causes
the device to read a command and address from the
PBUS.
16-11
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Table 16-6. Pin Descriptions (Continued)
Special-
function
Signal
Program-
ming
Mode
Port Pin
Type
Description
P2.2
PROG#
I
Slave
Programming
During programming, a falling edge latches data on
the PBUS and begins programming, while a rising
edge ends programming. The current location is
programmed with the same data as long as PROG#
remains asserted, so the data on the PBUS must
remain stable while PROG# is active.
During a word dump, a falling edge causes the
contents of an OTPROM location to be output on
the PBUS, while a rising edge ends the data
transfer.
P2.4
AINC#
I
Slave
Auto-increment
During slave programming, this active-low input
enables the auto-increment feature. (Auto increment
allows reading or writing of sequential OTPROM
locations, without requiring address transactions
across the PBUS for each read or write.) AINC# is
sampled after each location is programmed or
dumped. If AINC# is asserted, the address is
incremented and the next data word is programmed
or dumped.
P2.6
P2.7
CPVER
PACT#
PBUS
O
O
Slave
Cumulative Program Verification
During slave programming, a high signal indicates
that all locations programmed correctly, while a low
signal indicates that an error occurred during one of
the programming operations.
Auto
ROM-
dump
Programming Active
During auto programming or ROM-dump, a low
signal indicates that programming or dumping is in
progress, while a high signal indicates that the
operation is complete.
P4.7:0,
P3.7:0
I/O
Slave
Address/Command/Data Bus
During slave programming, ports 3 and 4 serve as a
bidirectional port with open-drain outputs to pass
commands, addresses, and data to or from the
device. Slave programming requires external pull-up
resistors.
P4.7:0, (MC,MD) PBUS
P3.7:0 (MC, MD)
I/O
Auto
ROM-
dump
Address/Command/Data Bus
During auto programming and ROM-dump, ports 3
and 4 serve as a regular system bus to access
external memory. For the 8XC196MH, P4.7:4 are
left unconnected; P1.3:0 serve as the upper address
lines.
P1.3:0, (MH)
P4.3:0, (MH)
P3.7:0 (MH)
16-12
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PROGRAMMING THE NONVOLATILE MEMORY
Table 16-6. Pin Descriptions (Continued)
Special-
function
Signal
Program-
ming
Mode
Port Pin
Type
Description
—
—
EA#
I
All
External Access
Controls program mode entry. If EA# is at VPP
voltage on the rising edge of RESET#, the device
enters programming mode.
EA# is sampled and latched only on the rising edge
of RESET#. Changing the level of EA# after reset
has no effect.
VPP
I
All
Programming Voltage
During programming, the VPP pin is typically at
+12.5V (VPP voltage). Exceeding the maximum VPP
voltage specification can damage the device.
16.7 ENTERING PROGRAMMING MODES
To execute programs properly, the device must have these minimum hardware connections:
XTAL1 driven, unused input pins strapped, and power and grounds applied. Follow the operating
conditions specified in the datasheet. Place the device into programming mode by applying VPP
voltage (+12.5 V) to EA# during the rising edge of RESET#.
16.7.1 Selecting the Programming Mode
The PMODE (P0.7:4) value controls the programming mode. PMODE is sampled on the rising
edge of RESET#. You must reset the device to switch programming modes. Table 16-7 lists the
PMODE value for each programming mode. All other PMODE values are reserved.
Table 16-7. PMODE Values
PMODE Value
Programming Mode
(Hex)
5
6
Slave programming
ROM-dump
9
UPROM programming (MH only)
Auto programming
C
D
PCCB programming (MH only)
16-13
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16.7.2 Power-up and Power-down Sequences
When you are ready to begin programming, follow these power-up and power-down procedures.
WARNING
Failure to observe these warnings will cause permanent device damage.
• Voltage must not be applied to VPP while VCC is low.
• The VPP voltage must be within 1 volt of VCC while VCC is less than 4.5 volts. VPP must not
go above 4.5 volts until VCC is at least 4.5 volts.
• The VPP maximum voltage must not be exceeded.
• EA# must reach programming voltage before VPP does so.
• The PMODE pins (P0.7:4) must be in their desired states before RESET# rises.
• All voltages must be within the ranges specified in the datasheet and the oscillator must be
stable before RESET# rises.
• The power supplies to the VCC, VPP, EA# and RESET# pins must be well regulated and free
of glitches and spikes.
• All VSS pins must be well grounded.
16.7.2.1
Power-up Sequence
1. Hold RESET# low while VCC stabilizes. Allow VPP and EA# to float during this time.
2. After VCC and the oscillator stabilize, continue to hold RESET# low and apply VPP voltage
to EA#.
3. After EA# stabilizes, apply VPP voltage (+12.5V) to the VPP pin.
4. Set the PMODE value to select a programming algorithm.
5. Bring the RESET# pin high.
6. Complete the selected programming algorithm.
16.7.2.2
Power-down Sequence
1. Assert the RESET# signal and hold it low throughout the powerdown sequence.
2. Remove the VPP voltage from the VPP pin and allow the pin to float.
3. Remove the VPP voltage from the EA# pin and allow the pin to float.
4. Turn off the VCC supply and allow time for it to reach 0 volts.
16-14
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PROGRAMMING THE NONVOLATILE MEMORY
16.8 SLAVE PROGRAMMING MODE
Slave programming mode allows you to program and verify the entire OTPROM array, including
the PCCBs and UPROM bits, by using an EPROM programmer.
In this mode, ports 3 and 4 serve as the PBUS, transferring commands, addresses, and data. The
least-significant bit of the PBUS (P3.0) controls the command (1 = program word; 0 = dump
word) and the remaining 15 bits contain the address of the word to be programmed or dumped.
Some port 2 pins provide handshaking signals. The AINC# signal controls whether the address
is automatically incremented, enabling programming or dumping sequential OTPROM locations.
This speeds up the programming process, since it eliminates the need to generate and decode each
sequential address.
NOTE
If a glitch or reset occurs during programming of the security key, an unknown
security key might accidentally be written, rendering the device inaccessible
for further programming. To prevent this possibility during slave
programming, program the rest of the OTPROM array before you program the
CCB security-lock bits (CCB0.6 and CCB0.7).
16.8.1 Reading the Signature Word and Programming Voltages
The signature word identifies the device; the programming voltages specify the VPP and VCC volt-
ages required for programming. This information resides in the test ROM at locations 2070H,
2072H, and 2073H; however, these locations are remapped to 0070H, 0072H, and 0073H. You
can use the dump word command in slave programming mode to read the signature word and pro-
gramming voltages at the locations shown in Table 16-8. The external programmer can use this
information to determine the device type and operating conditions. You should never write to
these locations. The voltages are calculated by using the following equation (after converting the
test ROM value to decimal).
20 × test ROM value
-----------------------------------------------------
Voltage
=
=
256
20 × 64
256
20 × 160
256
------------------
----------------------
= 12.5 volts
VCC (40H)
= 5 volts
VPP (0A0H)
=
16-15
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Table 16-8. Device Signature Word and Programming Voltages
Signature Word
Location Value
Programming VCC Programming VPP
Device
Location
Value Location Value
8XC196MC, MD
8XC196MH
0070H 8794H
0070H 87DEH
0072H
0072H
40H
40H
0073H 0A0H
0073H 0A0H
16.8.2 Slave Programming Circuit and Memory Map
Figure 16-5 shows the circuit diagram and Table 16-9 shows the memory map for slave program-
ming mode. The external clock signal can be supplied by either a clock or a crystal. Refer to the
device datasheet for acceptable clock frequencies.
CLOCK
VCC
XTAL1
VCC
10kΩ
VCC
VSS
RESET#
RESET#
PBUS
NMI
0.1 µF
P4.7:0
P3.7:0
Pullups Required
P4.7 - P3.0
EA#
VPP
EA#
VPP
P2.6
P2.4
P2.2
P2.1
P2.0
CPVER
AINC#
PROG#
PALE#
PVER
VCC
VREF
P0.7/PMODE.3
P0.6/PMODE.2
P0.5/PMODE.1
P0.4/PMODE.0
ANGND
87C196 Device
A0256-03
Figure 16-5. Slave Programming Circuit
16-16
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PROGRAMMING THE NONVOLATILE MEMORY
Table 16-9. Slave Programming Mode Memory Map
Description Address
Comments
OTPROM
(MH) 2000–9FFFH OTPROM Cells
(MC, MD) 2000–5FFFH
DED†
DEI†
0758H UPROM Cell
0718H UPROM Cell
PCCB
0218H Test EPROM
0072H, 0073H Read Only
0070H Read Only
Programming voltages (see Table 16-8 on page 16-16)
Signature word
†These bits program the UPROM cells. Once these bits are programmed, they cannot be erased and
dynamic failure analysis of the device is impossible.
16.8.3 Operating Environment
The chip configuration registers (CCRs) define the system environment. Since the programming
environment is not necessarily the same as the application environment, the device provides a
means for specifying different configurations. Specify your application environment in the chip
configuration bytes (CCBs) located in the OTPROM. Specify your programming environment in
the programming chip configuration bytes (PCCBs) located in the test ROM.
Figure 16-6 shows an abbreviated description of the CCRs with the default PCCB environment
settings. The reset sequence loads the CCRs from the CCBs for normal operation and from the
PCCBs when entering programming modes. You can program the CCBs using any of the pro-
gramming methods, but only slave mode allows you to program the PCCBs. Chapter 15, “Inter-
facing with External Memory,” describes the system configuration options, and “Controlling
Access to Internal Memory” on page 16-3 describes the memory protection options.
16-17
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CCR1, CCR0
no direct access
The chip configuration registers (CCRs) control wait states, powerdown mode, and internal memory
protection. These registers are loaded from the PCCBs during programming modes and from the CCBs
for normal operation.
7
0
1
1
0
1
WDE
ALE
BW1
WR
IRC2
BW0
0
7
0
LOC1
LOC0
IRC1
IRC0
PD
Bit Mnemonic
Function
WDE
BW1
IRC2
Watchdog Timer Enable
PCCB default is initially disabled (enabled the first time WDT is cleared).
Buswidth Control
PCCB default selects BUSWIDTH pin control.
Internal Ready Control
PCCB default selects READY pin control.
LOC1:0
IRC1:0
ALE
Security Bits
PCCB default selects no protection.
Internal Ready Control
PCCB default selects READY pin control.
Select Address Valid Strobe Mode
PCCB default selects ALE.
WR
Select Write Strobe Mode
PCCB default selects WR# and BHE#.
BW0
PD
Buswidth Control
PCCB default selects BUSWIDTH pin control.
Powerdown Enable
PCCB default enables powerdown.
Figure 16-6. Chip Configuration Registers (CCRs)
16-18
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PROGRAMMING THE NONVOLATILE MEMORY
16.8.4 Slave Programming Routines
The slave programming mode algorithm consists of three routines: the address/command decod-
ing routine, the program word routine, and the dump word routine.
The address/command decoding routine (Figure 16-7) reads the PBUS and transfers control to
the program word or dump word routine based on the value of P3.0. A one on P3.0 selects the
program word command and the remaining bits specify the address. For example, a PBUS value
of 3501H programs a word of data at location 3500H. A zero on P3.0 selects the dump word com-
mand and the remaining bits specify the address. For example, a PBUS value of 3500H places
the word at location 3500H on the PBUS.
The program word routine (Figure 16-8) checks the CCB security-lock bits. If either security lock
bit (CCB0.6 or CCB0.7) has been programmed, you must provide a matching security key to gain
access to the device. Using the program word command, write eight consecutive words to the de-
vice, starting at location 2020H and continuing to 202FH. The routine stores these eight words in
an internal register and compares their value with the internal key. If the keys match, the routine
allows you to program individual or sequential OTPROM locations; otherwise, the device enters
an endless loop.
The dump word routine (Figure 16-10) also checks the CCB security-lock bits, but it has no pro-
vision for security key verification. If the lock bits are unprogrammed, the routine fetches a word
of data from the OTPROM and writes that data to the PBUS. If either lock bit is programmed, the
routine performs a write cycle without first getting data from the OTPROM.
16-19
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No
No
Other
Modes
PMODE = 05H
?
Yes
PALE#
(P2.1) = 0
?
Yes
Read Data
From PBUS
PVER
(P2.0) = 1
?
No
Deassert CPVER
Assert PVER
Yes
PALE#
(P2.1)= 0
?
Yes
No
Check Address
Dump Word
Routine
No
P3.0 = 1
?
Yes
Program Word
Routine
A0193-02
Figure 16-7. Address/Command Decoding Routine
16-20
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PROGRAMMING THE NONVOLATILE MEMORY
From Address/
Command Decoder
No
PROG#
(P2.2)=0
?
Yes
Yes
Verify
Security Key
Lock Bits
Enabled
?
Read Data
from PBUS
No
Execute Modified
Quick-Pulse Algorithm
then Return
Keys
Match
?
Yes
No
Loop
Forever
Deassert
PVER (P2.0 = 0)
No
Programming
Verifies
?
Read Data
from PBUS
Yes
Assert PVER
(P2.0 = 1)
PROG#
(P2.2) = 0
?
Yes
No
Yes
PALE#
(P2.1) = 0
?
To Address/
Command Decoder
No
No
AINC#
(P2.4) = 0
?
Yes
No
Increment
Address by 2
PVER
(P2.0) = 1
?
Deassert CPVER
Assert PVER
Yes
A0194-03
Figure 16-8. Program Word Routine
16-21
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Figure 16-9 shows the timings of the program word command with a repeated programming pulse
and auto increment. Asserting PALE# latches the command and address on the PBUS. Asserting
PROG# latches the data on the PBUS and starts the programming sequence. The PROG# signal
controls the programming pulse width. (Slave programming mode does not use the PPW regis-
ter.) After the rising edge of PROG#, the routine verifies the contents of the location that was just
programmed and asserts PVER to indicate successful programming. AINC# is optional and can
automatically increment the address for the next location. If you do not use AINC#, you must
send a new program word command to access the next word location.
RESET#
T
DVPL
T
AVLL
ADDR1
ADDR2
DATA2
PBUS
(Ports 3/4)
ADDR/COMMAND
DATA1
T
T
SHLL
PLDX††
T
LLAX
PALE#
T
T
LLLH
LHPL
T
T
T
ILPL
PLPH
PHPL
†
†
PROG#
Pulse 1
T
ILVH
PVER
AINC#
T
PHVL
T
ILIH
T
PHIL
†
Additional program pulses and verifications.
†† Measure from falling edge of last PROG# pulse in sequence.
A0121-02
Figure 16-9. Program Word Waveform
16-22
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PROGRAMMING THE NONVOLATILE MEMORY
From Address/
Command Decoder
Yes
Lock Bits
Enabled
?
No
Get Data
from OPTROM
PROG#
(P2.2) = 0
?
No
Yes
Write Data
to PBUS
PROG#
(P2.2) = 1
?
No
Yes
Write 0FFFFH
to PBUS
PALE#
(P2.1) = 0
?
Yes
To Address/
Command Decoder
No
AINC#
(P2.4) = 0
?
No
Yes
Increment
Address by 2
A0189-03
Figure 16-10. Dump Word Routine
16-23
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Figure 16-11 shows the timings of the dump word command. PROG# governs when the device
drives the bus. The timings before the dump word command are the same as those shown in Fig-
ure 16-9. In the dump word mode, the AINC# pin can remain active and toggling. The PROG#
pin automatically increments the address.
RESET#
T
SHLL
ADDR1
ADDR2
PBUS
(Ports 3/4)
ADDR/COMMAND
Word Dump
Word Dump
T
T
T
T
PHDX
PLDV
PLDV
PHDX
PALE#
PROG#
T
ILPL
T
PHPL
AINC#
A0122-02
Figure 16-11. Dump Word Waveform
16.8.5 Timing Mnemonics
Table 16-10 defines the timing mnemonics used in the program word and dump word waveforms.
The datasheets include timing specifications for these signals.
Table 16-10. Timing Mnemonics
Mnemonic
Description
TSHLL
TLLLH
TAVLL
TLLAX
TPLDV
Reset High to First PALE# Low.
PALE# Pulse Width.
Address Setup Time.
Address Hold Time.
PROG# Low to Word Dump Valid.
Word Dump Data Hold.
Data Setup Time.
TPHDX
TDVPL
TPLDX
TPLPH
TPHLL
TLHPL
Data Hold Time.
PROG# Pulse Width.
PROG# High to Next PALE# Low.
PALE# High to PROG# Low.
16-24
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PROGRAMMING THE NONVOLATILE MEMORY
Table 16-10. Timing Mnemonics (Continued)
Mnemonic
Description
TPHPL
TPHIL
TILIH
PROG# High to Next PROG# Low.
PROG# High to AINC# Low.
AINC# Pulse Width.
TILVH
TILPL
TPHVL
PVER Hold After AINC# Low.
AINC# Low to PROG# Low.
PROG# High to PVER Valid.
16.9 AUTO PROGRAMMING MODE
The auto programming mode is a low-cost programming alternative. Using this programming
mode, the device programs itself with data from an external EPROM (external locations 4000H
and above; see Table 16-1 on page 16-3). A bank switching mechanism provided by port 1 pins
(see Figure 16-12) supports auto programming of devices with more than 16 Kbytes of internal
memory.
16.9.1 Auto Programming Circuit and Memory Map
Figure 16-12 shows the recommended circuit for auto programming mode. Table 16-11 shows the
8XC196MC/MD memory map and Table 16-11 shows the 8XC196MH auto programming mem-
ory map. Auto programming is specified for a crystal frequency of 6 to 8 MHz. At 8 MHz, use a
27(C)512 EPROM with tACC = 250 ns and tOE = 100 ns or faster specifications.
Tie the BUSWIDTH pin low to configure an 8-bit data bus. Connect P1.3:0 (8XC196MH only)
as shown to generate the high-order bits of the external EPROM address. Connect P0.7:4 to VSS
and VCC to select auto programming (1100B = 0CH). PACT# and PVER are status outputs, buff-
ered by the 74HC14s. They drive LEDs that indicate programming active (PACT#) and program-
ming verification (PVER). Connect all unused inputs to ground (VSS) and leave unused outputs
floating. READY and NMI are active; connect them as indicated.
NOTE
All external EPROM addresses specified in this section are given for the
circuit in Figure 16-12. If you choose a different circuit, you must adjust the
addresses accordingly.
16-25
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VCC
20 pF
20 pF
100 kΩ
XTAL1
XTAL2
Reset
RESET#
VCC
+5.0V
VCC
1 kΩ
74HC14
1.0µF
READY/P5.6
NMI
10µF
VSS
BUSWIDTH/P5.7
EA#
VPP
+12.50V
VCC
VREF
P0.7/
RD#/P5.3
PMODE.3
P0.6/
PMODE.2
OE# CE#
MH
P1.3:0
AD11:8
P0.5/
PMODE.1
A15:8
MC/MD
AD15:8
P0.4/
PMODE.0
VCC
ANGND
LE OE#
74LS373
270kΩ
ALE/P5.0
AD7:0
27(C)512
P2.7/PACT#
A7:0
74HC14
P2.5
P2.4
P2.3
P2.2
P2.1
ON = Programming
VCC
270kΩ
P2.0/PVER
74HC14
87C196Mx
ON = Error
A3111-01
Figure 16-12. Auto Programming Circuit
16-26
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PROGRAMMING THE NONVOLATILE MEMORY
Table 16-11. 8XC196MC/MD Auto Programming Memory Map
Address
Output from
8XC196MC,
8XC196MD
Address Using
Circuit in
Figure 16-12
(A15:0)
Internal
OTPROM
Address
Description
4014H
4015H
N/A
14H Programming pulse width (PPW) LSB.
15H Programming pulse width (PPW) MSB.
0020–002FH Security key for verification.
N/A
2020–202FH
2000–5FFFH
4020–402FH
4000–7FFFH
4000–7FFFH Code, data, and reserved locations.
Table 16-12. 8XC196MH Auto Programming Memory Map
Address Using
Internal
Address
Output from
8XC196MH
Circuit in
OTPROM
Address
Description
Figure 16-12
(P1.3:0, A11:0)
105EH
105FH
N/A
105EH Programming pulse width (PPW) LSB.
105FH Programming pulse width (PPW) MSB.
0020–002FH Security key for verification.
N/A
2020–202FH
2000–9FFFH
0020–002FH
2000–9FFFH
2000–9FFFH Code, data, and reserved locations.
16.9.2 Operating Environment
In the auto programming mode, the PCCBs are loaded into the chip configuration registers. Since
the device gets programming data through the external bus, the memory device in the program-
ming system must correspond to the default configuration (Figure 16-6 on page 16-18). Auto pro-
gramming requires an 8-bit bus configuration, so the circuit must tie the BUSWIDTH pin low.
The PCCB defaults allow you to use any standard EPROM that satisfies the AC specifications
listed in the device datasheet.
The auto programming mode also loads CCB0 into an internal RAM location and checks the lock
bits. If either lock bit is programmed, the auto programming routine compares the internal secu-
rity key to the external security key location. If the verification fails, the device enters an endless
internal loop. If the security keys match, the routine continues. The auto programming routine
uses the modified quick-pulse algorithm and the pulse width value programmed into the external
EPROM.
16.9.3 Auto Programming Routine
Figure 16-13 illustrates the auto programming routine. This routine checks the security lock bits
in CCB0; if either bit is programmed, it compares the internal security key to the external security
key locations. If the security keys match, the routine continues; otherwise, the device enters an
endless loop.
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No
Yes
Other
Modes
PMODE = 0CH
?
Lock Bits
Enabled
?
No
Yes
Verify
Security Key
No
Loop
Forever
Pass
?
Yes
Assert PACT#
Load PPW
Get External Data
Yes
Data = 0FFFFH
?
No
Execute Modified
Quick-Pulse Algorithm
then Return
Error
Programming
?
No
Yes
Clear PVER
Increment Address Pointer
Deassert PACT#
Loop Forever
(Done)
Top of
OTPROM
?
No
Yes
A0191-03
Figure 16-13. Auto Programming Routine
16-28
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PROGRAMMING THE NONVOLATILE MEMORY
If the security key verification is successful, the routine loads the programming pulse width
(PPW) value from the external EPROM into the internal PPW register. It then asserts PACT#, in-
dicating that programming has begun. (PACT# is also active during reset, although no program-
ming is in progress.) PVER is initially asserted and remains asserted unless an error is detected,
in which case it is deasserted.
The routine then reads the contents of the external EPROM, beginning at 4000H (2000H for the
8XC196MH). It skips any word that contains FFFFH (unprogrammed state). When it reads a
word that contains any value other than FFFFH, the routine calls the modified quick-pulse algo-
rithm, which writes that value to the OTPROM, using the appropriate number of pulses for the
device, then verifies the result. The routine repeats this activity until the entire OTPROM is pro-
grammed, then deasserts PACT# and enters an endless loop.
16.9.4 Auto Programming Procedure
If a glitch or reset occurs while programming the security key and lock bits, an unknown security
key might accidentally be written, rendering the device inaccessible for further programming. To
minimize this possibility, follow this recommended programming procedure.
NOTE
All addresses are given for the circuit shown in Figure 16-12 on page 16-26. If
you choose a different circuit, you must adjust the addresses accordingly.
1. Using a blank EPROM device, follow these steps to skip programming of CCB0 and
program the rest of the OTPROM array, including the security key.
— Place the programming pulse width (PPW) in external EPROM locations 14H–15H
(for the 8XC196MC, MD) or 105E–105FH (for the 8XC196MH).
— Leave the external CCB0 location (4018H) unprogrammed (0FFFFH).
— Place the appropriate CCB1 value at external location 401AH.
— Place the security key to be programmed in external EPROM locations 4020H–402FH
(for the 8XC196MC, MD) or 0020–002FH (for the 8XC196MH).
— Place the value 20H in external EPROM locations 4019H and 401BH (for the reserved
OTPROM locations that require this value).
— Place the desired code in the remaining external EPROM locations 4000–7FFFH (for
the 8XC196MC, MD) or 2000–9FFFH (for the 8XC196MH).
— Execute the power-up sequence (page 16-14) to initiate auto programming.
— When programming is complete, execute the powerdown sequence (page 16-14) before
continuing to step 2.
16-29
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2. Using another blank EPROM device, follow these steps to program only CCB0.
— Place the programming pulse width (PPW) in external locations 14H–15H.
— Place the appropriate CCB0 value in external location 4018H.
— Place the security key to be verified in external EPROM locations 0020H–002FH. This
value must match the security key programmed in step 1.
— Leave the remaining EPROM locations unprogrammed (0FFFFH).
— Execute the power-up sequence (page 16-14) to initiate auto programming.
— When programming is complete, follow the powerdown sequence (page 16-14).
At this point, you can modify the circuit, then use ROM-dump mode to write the entire OTPROM
array to an external memory device and verify its contents. (See “ROM-dump Mode” for details.)
16.9.5 ROM-dump Mode
The ROM-dump mode provides an easy way to verify the contents of the OTPROM array after
auto programming. Use the same circuit as for auto programming, but change the connections of
the PMODE (P0.7:4) pins. To select ROM-dump mode (PMODE=6H), connect P0.6 and P0.5 to
VCC and connect P0.7 and P0.4 to ground. The same bank switching mechanism is used and the
memory map is the same as that for auto programming. The example circuit (Figure 16-12 on
page 16-26) does not show the necessary WR# and VPP connections to allow writing to the
EPROM. And although the example uses an EPROM, you could also use a RAM device. Alter-
natively, you could dump the OTPROM contents to any 16-bit parallel port.
NOTE
If you have programmed the DED bit (USFR.2), ROM-dump mode is
disabled. (See “Controlling Fetches from External Memory” on page 16-6).
To enter ROM-dump mode, follow the power-up sequence on page 16-14. The ROM-dump mode
checks the security key, regardless of the CCR security-lock bits. If you have programmed a se-
curity key, a matching key must reside in the external memory; otherwise, the device enters an
endless loop. If the security key verifies, ROM-dump mode fetches the PPW, then writes the en-
tire OTPROM array to external memory. PACT# remains low while the dump is in progress, then
goes high to indicate that the dump is complete.
16.10 PCCB AND UPROM PROGRAMMING (8XC196MH ONLY)
The PCCB and UPROM programming modes are useful if you have auto programmed and veri-
fied the rest of the OTPROM array and now need to program only the PCCB and UPROM bits.
(With slave programming mode, you can program the PCCB and UPROM bits along with the rest
of the array.)
16-30
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PROGRAMMING THE NONVOLATILE MEMORY
Figure 16-14 shows the recommended circuit for PCCB and UPROM programming. In these cir-
cuits, the PBUS holds data to be written to the OTPROM, PALE# begins programming, and
PVER drives an LED that lights to indicate successful programming.
VCC
20 pF
1.0µF
20 pF
100 kΩ
XTAL1
XTAL2
Reset
RESET#
VCC
VSS
+5.0V
VCC
1 kΩ
74HC14
READY/P5.6
NMI
10µF
BUSWIDTH/P5.7
EA#
VPP
+12.50V
VCC
VCC
10kΩ
VREF
SW1
Pullups Required
P4.7 – P3.0
P0.7
P0.6
P0.5
P4.7:0
P3.7:0
P0.4
P0.3:0
P1.4:0
P2.5:2
ANGND
PMODE = 0DH PCCB Mode
PMODE = 09H UPROM Mode
PCCB/UPROM
Value
SW2
VCC
P2.1/PALE#
10kΩ
Push to Program
270kΩ
P2.0/PVER
74HC14
87C196 Device
A3003-02
Figure 16-14. PCCB and UPROM Programming Circuit
To enter either mode, follow the standard power-up sequence (page 16-14) after setting the values
listed in Table 16-13. If you want to program both the PCCB and the UPROM bits, program one
of them and complete the power-down sequence. Then reconfigure the PMODE and port 3 pins
and repeat the power-up sequence.
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Table 16-13. PCCB and UPROM Programming Values
PCCB Programming UPROM Programming
Pins
PMODE3:0 0DH
09H
P4.7:0
P3.7:0
FFH
FFH
Data to be programmed in PCCB
Value to program UPROM bits:
(See CCR descriptions in Appendix C)
04H to program DED only
08H to program DEI only
0CH to program both DED and DEI
Assert PALE# to begin programming. The algorithm sends five programming pulses that write
the port 3 data to the OTPROM, then it compares the input data with the programmed data. If the
programming verifies, the PVER signal lights the LED to indicate successful programming. Oth-
erwise, you can pulse PALE# to repeat programming. Complete the procedure by following the
power-down sequence (page 16-14).
NOTE
The PCCB and UPROM programming modes are available only for the
8XC196MH device. The pulse width is 200 µs at 8 MHz or 266 µs at 6 MHz.
16.11 RUN-TIME PROGRAMMING
You can program an OTPROM location during normal code execution. To make the OTPROM
array accessible, apply VCC voltage to EA# while you reset the device. Apply VPP voltage to the
VPP pin during the entire programming process. Then simply write to the location to be pro-
grammed.
NOTE
Programming either security-lock bit in CCB0 disables run-time
programming. (For details, see “Controlling Access to the OTPROM During
Normal Operation” on page 16-4.)
Immediately after writing to the OTPROM, the device must either enter idle mode or execute
code from external memory. An access to OTPROM would abort the current programming cycle.
Each programming cycle begins when a word is written to the OTPROM and ends when the next
OTPROM access occurs. Each word requires a total of five programming cycles, each of which
must be approximately 100 µs in duration.
Figure 16-15 is a run-time programming example. It performs five programming cycles for each
word. After each programming cycle, the code causes the device to enter idle mode.
16-32
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PROGRAMMING THE NONVOLATILE MEMORY
The calling routine must pass two parameters to this routine — the data to be programmed (in
DATA_TEMP) and the address (in ADDR_TEMP).
PROGRAM:
PUSHA
LD
LD
;clear PSW, WSR, INT_MASK, INT_MASK1
;select 32-byte window with EPA0_CON
;set up for 5 programming cycles
;clear EPA0 pending bit
;enable EPA0 interrupt
;set up EPA0 as software timer
WSR,#7BH
COUNT,#5
ANDB INT_PEND,#CLEAR_EPA0
LDB INT_MASK,#ENABLE_EPA0
LDB EPA0_CON,#EPA0_TIMER
LOOP:
LD
TEMP0,TIMER1
;load TIMER1 value into TEMP0
ADD EPA0_TIME,TEMP0,#PGM_PULSE
;load EPA0_TIME with TIMER1 + PGM_PULSE
;enable unmasked interrupt(EPA0)
;store passed data at passed address
;enter idle mode
EI
ST
IDLPD #1
DATA_TEMP,[ADDR_TEMP]
DJNZ COUNT,LOOP
;decrement COUNT and loop if not 0
;to complete 5 programming cycles
;restore PSW, WSR, and INT_MASKs
POPA
RET
EPA0_ISR:
RET
Figure 16-15. Run-time Programming Code Example
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A
Instruction Set
Reference
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APPENDIX A
INSTRUCTION SET REFERENCE
®
This appendix provides reference information for the instruction set of the family of MCS 96
microcontrollers. It defines the processor status word (PSW) flags, describes each instruction,
shows the relationships between instructions and PSW flags, and shows hexadecimal opcodes,
instruction lengths, and execution times. It includes the following tables.
• Table A-1 on page A-2 is a map of the opcodes.
• Table A-2 on page A-4 defines the processor status word (PSW) flags.
• Table A-3 on page A-5 shows the effect of the PSW flags or a specified register bit on
conditional jump instructions.
• Table A-4 on page A-5 defines the symbols used in Table A-6.
• Table A-5 on page A-6 defines the variables used in Table A-6 to represent instruction
operands.
• Table A-6 beginning on page A-7 lists the instructions alphabetically, describes each of
them, and shows the effect of each instruction on the PSW flags.
• Table A-7 beginning on page A-41 lists the instruction opcodes, in hexadecimal order,
along with the corresponding instruction mnemonics.
• Table A-8 on page A-47 lists instruction lengths and opcodes for each applicable addressing
mode.
• Table A-9 on page A-52 lists instruction execution times, expressed in state times.
NOTE
The # symbol prefixes an immediate value in immediate addressing mode.
Chapter 3, “Programming Considerations,” describes the operand types and
addressing modes.
A-1
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Table A-1. Opcode Map (Left Half)
Opcode
0x
x0
x1
x2
x3
x4
XCH
di
x5
x6
x7
SKIP
CLR
NOT
NEG
DEC
EXT
INC
CLRB
NOTB
NEGB
XCHB
di
DECB
EXTB
INCB
1x
2x
3x
4x
5x
6x
7x
8x
9x
Ax
Bx
Cx
Dx
SJMP
JBC
bit 0
di
bit 1
bit 2
in
bit 3
ix
bit 4
di
bit 5
bit 6
in
bit 7
ix
AND 3op
ADD 3op
im
im
im
im
im
im
ANDB 3op
ADDB 3op
di
in
ix
di
in
ix
AND 2op
ADD 2op
di
in
ix
di
in
ix
ANDB 2op
im in
ADDB 2op
im in
di
ix
di
ix
OR
ORB
LD
XOR
XORB
ADDC
ADDCB
di
im
im
im
in
in
in
in
ix
di
im
im
im
im
in
in
in
in
ix
di
ix
di
ix
di
ix
di
ix
LDB
di
ST
im
ix
di
STB
di
ix
BMOV
ST
CMPL
JNV
STB
di
in
ix
in
ix
JNST
JNH
JGT
JNC
JNVT
JGE
JNE
BR
in
Ex
Fx
DJNZ
RET
DJNZW
TIJMP
LJMP
TRAP
PUSHF
POPF
PUSHA
POPA
IDLPD
NOTE: The first digit of the opcode is listed vertically, and the second digit is listed horizontally. The
related instruction mnemonic is shown at the intersection of the two digits. Shading indicates
reserved opcodes. If the CPU attempts to execute an unimplemented opcode, an interrupt
occurs. For more information, see “Unimplemented Opcode” on page 5-6.
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INSTRUCTION SET REFERENCE
Table A-1. Opcode Map (Right Half)
Opcode
0x
x8
x9
xA
xB
XCH
ix
xC
xD
xE
xF
SHR
SHL
SHRA
SHRL
SHLL
SHRAL
NORML
SHRB
SHLB
SHRAB
XCHB
ix
1x
2x
3x
4x
5x
6x
7x
8x
9x
Ax
Bx
Cx
SCALL
JBS
bit 0
di
bit 1
bit 2
in
bit 3
ix
bit 4
di
bit 5
bit 6
bit 7
ix
SUB 3op
MULU 3op (Note 2)
im in
MULUB 3op (Note 2)
im in
MULU 2op (Note 2)
im in
MULUB 2op (Note 2)
im in
DIVU (Note 2)
im in
DIVUB (Note 2)
im
im
im
SUBB 3op
di
in
ix
di
ix
SUB 2op
di
in
ix
di
ix
SUBB 2op
im in
di
ix
di
ix
CMP
CMPB
SUBC
SUBCB
PUSH
di
im
im
im
im
in
in
in
in
ix
di
ix
di
ix
di
im
im
im
in
in
in
ix
LDBZE
LDBSE
di
ix
di
ix
di
ix
di
POP
di
ix
BMOVI
POP
di
im
in
ix
in
ix
JST
JH
JLE
JC
JVT
JV
JLT
JE
Dx
Ex
DPTS
(Note 1)
LCALL
RST
CLRC
SETC
DI
EI
CLRVT
NOP
signed
MUL/DIV
(Note 2)
Fx
NOTES:
1. This opcode is reserved, but it does not generate an unimplemented opcode interrupt.
2. Signed multiplication and division are two-byte instructions. The first byte is “FE” and the second is the
opcode of the corresponding unsigned instruction.
A-3
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Table A-2. Processor Status Word (PSW) Flags
Mnemonic
Description
C
The carry flag is set to indicate an arithmetic carry from the MSB of the ALU or the state of
the last bit shifted out of an operand. If a subtraction operation generates a borrow, the carry
flag is cleared.
C
0
1
Value of Bits Shifted Off
< ½ LSB
≥ ½ LSB
Normally, the result is rounded up if the carry flag is set. The sticky bit flag allows a finer
resolution in the rounding decision.
C
0
0
1
1
ST
0
Value of Bits Shifted Off
= 0
1
> 0 and < ½ LSB
= ½ LSB
0
1
> ½ LSB and < 1 LSB
N
The negative flag is set to indicate that the result of an operation is negative. The flag is
correct even if an overflow occurs. For all shift operations and the NORML instruction, the
flag is set to equal the most-significant bit of the result, even if the shift count is zero.
ST
The sticky bit flag is set to indicate that, during a right shift, a “1” has been shifted into the
carry flag and then shifted out. This bit is undefined after a multiply operation. The sticky bit
flag can be used with the carry flag to allow finer resolution in rounding decisions. See the
description of the carry (C) flag for details.
V
The overflow flag is set to indicate that the result of an operation is too large to be
represented correctly in the available space.
For shift operations, the flag is set if the most-significant bit of the operand changes during
the shift. For divide operations, the quotient is stored in the low-order half of the destination
operand and the remainder is stored in the high-order half. The overflow flag is set if the
quotient is outside the range for the low-order half of the destination operand. (Chapter 3,
“Programming Considerations,” defines the operands and possible values for each.)
Instruction Quotient Stored in: V Flag Set if Quotient is:
DIVB
DIV
Short-integer
Integer
< –128 or > +127 (< 81H or > 7FH)
< –32768 or > +32767 (< 8001H or > 7FFFH)
> 255 (FFH)
DIVUB Byte
DIVU Word
> 65535 (FFFFH)
VT
Z
The overflow-trap flag is set when the overflow flag is set, but it is cleared only by the CLRVT,
JVT, and JNVT instructions. This allows testing for a possible overflow at the end of a
sequence of related arithmetic operations, which is generally more efficient than testing the
overflow flag after each operation.
The zero flag is set to indicate that the result of an operation was zero. For multiple-precision
calculations, the zero flag cannot be set by the instructions that use the carry bit from the
previous calculation (e.g., ADDC, SUBC). However, these instructions can clear the zero
flag. This ensures that the zero flag will reflect the result of the entire operation, not just the
last calculation. For example, if the result of adding together the lower words of two double
words is zero, the zero flag would be set. When the upper words are added together using
the ADDC instruction, the flag remains set if the result is zero and is cleared if the result is not
zero.
A-4
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Table A-3 shows the effect of the PSW flags or a specified condition on conditional jump instruc-
tions. Table A-4 defines the symbols used in Table A-6 to show the effect of each instruction on
the PSW flags.
Table A-3. Effect of PSW Flags or Specified Conditions on Conditional Jump Instructions
Instruction
Jumps to Destination if
decremented byte ≠ 0
decremented word ≠ 0
specified register bit = 0
specified register bit = 1
C = 0
Continues if
DJNZ
decremented byte = 0
decremented word = 0
specified register bit = 1
specified register bit = 0
C = 1
DJNZW
JBC
JBS
JNC
JNH
JC
C = 0 OR Z = 1
C = 1
C = 1 AND Z = 0
C = 0
JH
C = 1 AND Z = 0
N = 0
C = 0 OR Z = 1
N = 1
JGE
JGT
JLT
N = 0 AND Z = 0
N = 1
N = 1 OR Z = 1
N = 0
JLE
JNST
JST
JNV
JV
N = 1 OR Z = 1
ST = 0
N = 0 AND Z = 0
ST = 1
ST = 1
ST = 0
V = 0
V = 1
V = 1
V = 0
JNVT
JVT
JNE
JE
VT = 0
VT = 1 (clears VT)
VT = 0
VT = 1 (clears VT)
Z = 0
Z = 1
Z = 1
Z = 0
.
Table A-4. PSW Flag Setting Symbols
Description
Symbol
✓
—
↓
↑
1
The instruction sets or clears the flag, as appropriate.
The instruction does not modify the flag.
The instruction may clear the flag, if it is appropriate, but cannot set it.
The instruction may set the flag, if it is appropriate, but cannot clear it.
The instruction sets the flag.
0
The instruction clears the flag.
?
The instruction leaves the flag in an indeterminate state.
A-5
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Table A-5 defines the variables that are used in Table A-6 to represent the instruction operands.
Table A-5. Operand Variables
Variable
aa
Description
A 2-bit field within an opcode that selects the basic addressing mode used. This field is present
only in those opcodes that allow addressing mode options. The field is encoded as follows:
00 register-direct
01 immediate
10 indirect
11 indexed
baop
bbb
A byte operand that is addressed by any addressing mode.
A 3-bit field within an opcode that selects a specific bit within a register.
A 3-bit field within an opcode that selects one of the eight bits in a byte.
bitno
breg
A byte register in the internal register file. When it could be unclear whether this variable refers
to a source or a destination register, it is prefixed with an S or a D. The value must be in the
range of 00–FFH.
cadd
An address in the program code.
Dbreg†
A byte register in the lower register file that serves as the destination of the instruction
operation.
disp
Displacement. The distance between the end of an instruction and the target label.
Dlreg†
A 32-bit register in the lower register file that serves as the destination of the instruction
operation. Must be aligned on an address that is evenly divisible by 4. The value must be in the
range of 00–FCH.
Dwreg†
A word register in the lower register file that serves as the destination of the instruction
operation. Must be aligned on an address that is evenly divisible by 2. The value must be in the
range of 00–FEH.
lreg
A 32-bit register in the lower register file. Must be aligned on an address that is evenly divisible
by 4. The value must be in the range of 00–FCH.
preg
A pointer register. Must be aligned on an address that is evenly divisible by 4. The value must
be in the range of 00–FCH.
Sbreg†
Slreg†
A byte register in the lower register file that serves as the source of the instruction operation.
A 32-bit register in the lower register file that serves as the source of the instruction operation.
Must be aligned on an address that is evenly divisible by 4. The value must be in the range of
00–FCH.
Swreg†
A word register in the lower register file that serves as the source of the instruction operation.
Must be aligned on an address that is evenly divisible by 2. The value must be in the range of
00–FEH.
waop
A word operand that is addressed by any addressing mode.
w2_reg
A double-word register in the lower register file. Must be aligned on an address that is evenly
divisible by 4. The value must be in the range of 00–FCH. Although w2_reg is similar to lreg,
there is a distinction: w2_reg consists of two halves, each containing a 16-bit address; lreg is
indivisible and contains a 32-bit number.
wreg
A word register in the lower register file. When it could be unclear whether this variable refers
to a source or a destination register, it is prefixed with an S or a D. Must be aligned on an
address that is evenly divisible by 2. The value must be in the range of 00–FEH.
xxx
The three high-order bits of displacement.
†
The D or S prefix is used only when it could be unclear whether a variable refers to a destination or a
source register.
A-6
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Table A-6. Instruction Set
Operation
ADD WORDS. Adds the source and
Mnemonic
Instruction Format
ADD
DEST, SRC
wreg, waop
(2 operands) destination word operands and stores the
ADD
sum into the destination operand.
(011001aa) (waop) (wreg)
(DEST) ← (DEST) + (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
ADD
ADD WORDS. Adds the two source word
DEST, SRC1, SRC2
Dwreg, Swreg, waop
(010001aa) (waop) (Swreg) (Dwreg)
(3 operands) operands and stores the sum into the
destination operand.
ADD
(DEST) ← (SRC1) + (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
ADDB
ADD BYTES. Adds the source and
DEST, SRC
breg, baop
(011101aa) (baop) (breg)
(2 operands) destination byte operands and stores the sum
into the destination operand.
ADDB
(DEST) ← (DEST) + (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
ADDB
ADD BYTES. Adds the two source byte
DEST, SRC1, SRC2
Dbreg, Sbreg, baop
(010101aa) (baop) (Sbreg) (Dbreg)
(3 operands) operands and stores the sum into the
ADDB
destination operand.
(DEST) ← (SRC1) + (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
ADDC
ADD WORDS WITH CARRY. Adds the
source and destination word operands and
the carry flag (0 or 1) and stores the sum into
the destination operand.
DEST, SRC
wreg, waop
(101001aa) (waop) (wreg)
ADDC
(DEST) ← (DEST) + (SRC) + C
PSW Flag Settings
Z
N
C
V
VT ST
↓
✓
✓
✓
↑
—
A-7
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
ADDCB
ADD BYTES WITH CARRY. Adds the source
and destination byte operands and the carry
flag (0 or 1) and stores the sum into the
destination operand.
DEST, SRC
ADDCB breg, baop
(101101aa) (baop) (breg)
(DEST) ← (DEST) + (SRC) + C
PSW Flag Settings
Z
N
C
V
VT ST
↓
✓
✓
✓
↑
—
AND
LOGICAL AND WORDS. ANDs the source
DEST, SRC
wreg, waop
(011000aa) (waop) (wreg)
(2 operands) and destination word operands and stores
the result into the destination operand. The
result has ones in only the bit positions in
which both operands had a “1” and zeros in
all other bit positions.
AND
(DEST) ← (DEST) AND (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
AND
LOGICAL AND WORDS. ANDs the two
DEST, SRC1, SRC2
Dwreg, Swreg, waop
(010000aa) (waop) (Swreg) (Dwreg)
(3 operands) source word operands and stores the result
into the destination operand. The result has
ones in only the bit positions in which both
operands had a “1” and zeros in all other bit
positions.
AND
(DEST) ← (SRC1) AND (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
ANDB
LOGICAL AND BYTES. ANDs the source
DEST, SRC
breg, baop
(011100aa) (baop) (breg)
(2 operands) and destination byte operands and stores the
result into the destination operand. The result
has ones in only the bit positions in which
both operands had a “1” and zeros in all other
bit positions.
ANDB
(DEST) ← (DEST) AND (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
A-8
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
ANDB
LOGICAL AND BYTES. ANDs the two source
DEST, SRC1, SRC2
Dbreg, Sbreg, baop
(3 operands) byte operands and stores the result into the
destination operand. The result has ones in
only the bit positions in which both operands
had a “1” and zeros in all other bit positions.
ANDB
(010100aa) (baop) (Sbreg) (Dbreg)
(DEST) ← (SRC1) AND (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
BMOV
BLOCK MOVE. Moves a block of word data
from one location in memory to another. The
source and destination addresses are
calculated using the indirect with autoin-
crement addressing mode. A long register
(PTRS) addresses the source and destination
pointers, which are stored in adjacent word
registers. The source pointer (SRCPTR) is
the low word and the destination pointer
(DSTPTR) is the high word of PTRS. A word
register (CNTREG) specifies the number of
transfers. The blocks of word data can be
located anywhere in register RAM, but should
not overlap.
PTRS, CNTREG
lreg, wreg
BMOV
(11000001) (wreg) (lreg)
NOTE: The pointers are autoincre-
mented during this instruction.
However, CNTREG is not decre-
mented. Therefore, it is easy to
unintentionally create a long,
uninterruptible operation with the
BMOV instruction. Use the
BMOVI instruction for an interrupt-
ible operation.
COUNT ← (CNTREG)
LOOP: SRCPTR ← (PTRS)
DSTPTR ← (PTRS + 2)
(DSTPTR) ← (SRCPTR)
(PTRS) ← SRCPTR + 2
(PTRS + 2) ← DSTPTR + 2
COUNT ← COUNT – 1
if COUNT ≠ 0 then
go to LOOP
end_if
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-9
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
BMOVI
INTERRUPTIBLE BLOCK MOVE. Moves a
block of word data from one location in
memory to another. The instruction is
identical to BMOV, except that BMOVI is
interruptible. The source and destination
addresses are calculated using the indirect
with autoincrement addressing mode. A long
register (PTRS) addresses the source and
destination pointers, which are stored in
adjacent word registers. The source pointer
(SRCPTR) is the low word and the
destination pointer (DSTPTR) is the high
word of PTRS. A word register (CNTREG)
specifies the number of transfers. The blocks
of word data can be located anywhere in
register RAM, but should not overlap.
PTRS, CNTREG
BMOVI lreg, wreg
(11001101) (wreg) (lreg)
NOTE: The pointers are autoincre-
mented during this instruction.
However, CNTREG is decre-
mented only when the instruction
is interrupted. When BMOVI is
interrupted, CNTREG is updated
to store the interim word count at
the time of the interrupt. For this
reason, you should always reload
CNTREG before starting a
BMOVI.
COUNT ← (CNTREG)
LOOP: SRCPTR ← (PTRS)
DSTPTR ← (PTRS + 2)
(DSTPTR) ← (SRCPTR)
(PTRS) ← SRCPTR + 2
(PTRS + 2) ← DSTPTR + 2
COUNT ← COUNT – 1
if COUNT ≠ 0 then
go to LOOP
end_if
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
BR
BRANCH INDIRECT. Continues execution at
the address specified in the operand word
register.
DEST
BR
[wreg]
(11100011) (wreg)
PC ← (DEST)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
CLR
CLEAR WORD. Clears the value of the
operand.
DEST
wreg
(00000001) (wreg)
CLR
(DEST) ← 0
PSW Flag Settings
Z
N
C
V
VT ST
1
0
0
0
—
—
A-10
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
DEST
breg
CLRB
CLEAR BYTE. Clears the value of the
operand.
CLRB
(DEST) ← 0
(00010001) (breg)
PSW Flag Settings
Z
N
C
V
VT ST
1
0
0
0
—
—
CLRC
CLEAR CARRY FLAG. Clears the carry flag.
C ← 0
CLRC
(11111000)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
0
—
—
—
CLRVT
CLEAR OVERFLOW-TRAP FLAG. Clears
the overflow-trap flag.
CLRVT
VT ← 0
(11111100)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
0
—
CMP
COMPARE WORDS. Subtracts the source
word operand from the destination word
operand. The flags are altered, but the
operands remain unaffected. If a borrow
occurs, the carry flag is cleared; otherwise, it
is set.
DEST, SRC
wreg, waop
(100010aa) (waop) (wreg)
CMP
(DEST) – (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
CMPB
COMPARE BYTES. Subtracts the source
byte operand from the destination byte
operand. The flags are altered, but the
operands remain unaffected. If a borrow
occurs, the carry flag is cleared; otherwise, it
is set.
DEST, SRC
breg, baop
(100110aa) (baop) (breg)
CMPB
(DEST) – (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
A-11
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
CMPL
COMPARE LONG. Compares the
DEST, SRC
Dlreg, Slreg
magnitudes of two double-word (long)
operands. The operands are specified using
the direct addressing mode. The flags are
altered, but the operands remain unaffected.
If a borrow occurs, the carry flag is cleared;
otherwise, it is set.
CMPL
(11000101) (Slreg) (Dlreg)
(DEST) – (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
✓
—
DEC
DECB
DI
DECREMENT WORD. Decrements the value
of the operand by one.
DEST
wreg
(00000101) (wreg)
DEC
(DEST) ← (DEST) –1
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
DECREMENT BYTE. Decrements the value
of the operand by one.
DEST
breg
DECB
(DEST) ← (DEST) –1
(00010101) (breg)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
DISABLE INTERRUPTS. Disables
interrupts. Interrupt calls cannot occur after
this instruction.
DI
(11111010)
Interrupt Enable (PSW.1) ← 0
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-12
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
DIV
DIVIDE INTEGERS. Divides the contents of
the destination long-integer operand by the
contents of the source integer word operand,
using signed arithmetic. It stores the quotient
into the low-order word of the destination
(i.e., the word with the lower address) and the
remainder into the high-order word. The
following two statements are performed
concurrently.
DEST, SRC
lreg, waop
DIV
(11111110) (100011aa) (waop) (lreg)
(low word DEST) ← (DEST) / (SRC)
(high word DEST) ← (DEST) MOD (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
✓
↑
—
DIVB
DIVIDE SHORT-INTEGERS. Divides the
contents of the destination integer operand
by the contents of the source short-integer
operand, using signed arithmetic. It stores the
quotient into the low-order byte of the
destination (i.e., the word with the lower
address) and the remainder into the high-
order byte. The following two statements are
performed concurrently.
DEST, SRC
wreg, baop
(11111110) (100111aa) (baop) (wreg)
DIVB
(low byte DEST) ← (DEST) / (SRC)
(high byte DEST) ← (DEST) MOD (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
✓
↑
—
DIVU
DIVIDE WORDS, UNSIGNED. Divides the
contents of the destination double-word
operand by the contents of the source word
operand, using unsigned arithmetic. It stores
the quotient into the low-order word (i.e., the
word with the lower address) of the
DEST, SRC
lreg, waop
(100011aa) (waop) (lreg)
DIVU
destination operand and the remainder into
the high-order word. The following two
statements are performed concurrently.
(low word DEST) ← (DEST) / (SRC)
(high word DEST) ← (DEST) MOD (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
✓
↑
—
A-13
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
DIVUB
DIVIDE BYTES, UNSIGNED. This instruction
divides the contents of the destination word
operand by the contents of the source byte
operand, using unsigned arithmetic. It stores
the quotient into the low-order byte (i.e., the
byte with the lower address) of the
DEST, SRC
DIVUB wreg, baop
(100111aa) (baop) (wreg)
destination operand and the remainder into
the high-order byte. The following two
statements are performed concurrently.
(low byte DEST) ← (DEST) / (SRC)
(high byte DEST) ← (DEST) MOD (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
✓
↑
—
DJNZ
DECREMENT AND JUMP IF NOT ZERO.
Decrements the value of the byte operand by
1. If the result is 0, control passes to the next
sequential instruction. If the result is not 0,
the instruction adds to the program counter
the offset between the end of this instruction
and the target label, effecting the jump. The
offset must be in the range of –128 to +127.
DJNZ
breg, cadd
(11100000) (breg) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
(COUNT) ← (COUNT) –1
if (COUNT) ≠ 0 then
PC ← PC + 8-bit disp
end_if
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
DJNZW
DECREMENT AND JUMP IF NOT ZERO
WORD. Decrements the value of the word
operand by 1. If the result is 0, control passes
to the next sequential instruction. If the result
is not 0, the instruction adds to the program
counter the offset between the end of this
instruction and the target label, effecting the
jump. The offset must be in the range of –128
to +127.
DJNZW wreg, cadd
(11100001) (wreg) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits
(COUNT) ← (COUNT) –1
if (COUNT) ≠ 0 then
PC ← PC + 8-bit disp
end_if
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-14
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
DPTS
DISABLE PERIPHERAL TRANSACTION
SERVER (PTS). Disables the peripheral
transaction server (PTS).
DPTS
(11101100)
PTS Disable (PSW.2) ← 0
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
EI
ENABLE INTERRUPTS. Enables interrupts
following the execution of the next statement.
Interrupt calls cannot occur immediately
following this instruction.
EI
(11111011)
Interrupt Enable (PSW.1) ← 1
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
EPTS
ENABLE PERIPHERAL TRANSACTION
SERVER (PTS). Enables the peripheral
transaction server (PTS).
EPTS
(11101101)
PTS Enable (PSW.2) ← 1
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
EXT
SIGN-EXTEND INTEGER INTO LONG-
INTEGER. Sign-extends the low-order word
of the operand throughout the high-order
word of the operand.
EXT
lreg
(00000110) (lreg)
if DEST.15 = 1 then
(high word DEST) ← 0FFFFH
else
(high word DEST) ← 0
end_if
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
A-15
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Table A-6. Instruction Set (Continued)
Operation Instruction Format
Mnemonic
EXTB
SIGN-EXTEND SHORT-INTEGER INTO
INTEGER. Sign-extends the low-order byte
of the operand throughout the high-order byte
of the operand.
EXTB
wreg
(00010110) (wreg)
if DEST.7 = 1 then
(high byte DEST) ← 0FFH
else
(high byte DEST) ← 0
end_if
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
IDLPD
IDLE/POWERDOWN. Depending on the 8-bit
value of the KEY operand, this instruction
causes the device to:
IDLPD
#key
(11110110) (key)
•
•
•
enter idle mode, if KEY=1,
enter powerdown mode, if KEY=2,
execute a reset sequence,
if KEY = any value other than 1 or 2.
The bus controller completes any prefetch
cycle in progress before the CPU stops or
resets.
if KEY = 1 then
enter idle
else if KEY = 2 then
enter powerdown
else
execute reset
PSW Flag Settings
Z
N
C
V
VT ST
KEY = 1 or 2
—
—
—
—
—
—
KEY = any value other than
1 or 2
0
0
0
0
0
0
INC
INCREMENT WORD. Increments the value
of the word operand by 1.
INC
wreg
(DEST) ← (DEST) + 1
(00000111) (wreg)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
0
A-16
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
INCB
INCREMENT BYTE. Increments the value of
the byte operand by 1.
INCB
breg
(DEST) ← (DEST) + 1
(00010111) (breg)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
JBC
JUMP IF BIT IS CLEAR. Tests the specified
bit. If the bit is set, control passes to the next
sequential instruction. If the bit is clear, this
instruction adds to the program counter the
offset between the end of this instruction and
the target label, effecting the jump. The offset
must be in the range of –128 to +127.
JBC
breg, bitno, cadd
(00110bbb) (breg) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if (specified bit) = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JBS
JUMP IF BIT IS SET. Tests the specified bit. If
the bit is clear, control passes to the next
sequential instruction. If the bit is set, this
instruction adds to the program counter the
offset between the end of this instruction and
the target label, effecting the jump. The offset
must be in the range of –128 to +127.
JBS
breg, bitno, cadd
(00111bbb) (breg) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if (specified bit) = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-17
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Table A-6. Instruction Set (Continued)
Operation Instruction Format
Mnemonic
JC
JUMP IF CARRY FLAG IS SET. Tests the
carry flag. If the carry flag is clear, control
passes to the next sequential instruction. If
the carry flag is set, this instruction adds to
the program counter the offset between the
end of this instruction and the target label,
effecting the jump. The offset must be in the
range of –128 to +127.
JC
cadd
(11011011) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if C = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JE
JUMP IF EQUAL. Tests the zero flag. If the
flag is clear, control passes to the next
JE
cadd
sequential instruction. If the zero flag is set,
this instruction adds to the program counter
the offset between the end of this instruction
and the target label, effecting the jump. The
offset must be in the range of –128 to +127.
(11011111) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if Z = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JGE
JUMP IF SIGNED GREATER THAN OR
EQUAL. Tests the negative flag. If the
negative flag is set, control passes to the next
sequential instruction. If the negative flag is
clear, this instruction adds to the program
counter the offset between the end of this
instruction and the target label, effecting the
jump. The offset must be in the range of –128
to +127.
JGE
cadd
(11010110) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if N = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-18
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
JGT
JUMP IF SIGNED GREATER THAN. Tests
both the zero flag and the negative flag. If
either flag is set, control passes to the next
sequential instruction. If both flags are clear,
this instruction adds to the program counter
the offset between the end of this instruction
and the target label, effecting the jump. The
offset must be in the range of –128 to +127.
JGT
cadd
(11010010) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if N = 0 AND Z = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JH
JUMP IF HIGHER (UNSIGNED). Tests both
the zero flag and the carry flag. If either the
carry flag is clear or the zero flag is set,
control passes to the next sequential
instruction. If the carry flag is set and the zero
flag is clear, this instruction adds to the
program counter the offset between the end
of this instruction and the target label,
effecting the jump. The offset must be in
range of –128 to +127.
JH
cadd
(11011001) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if C = 1 AND Z = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JLE
JUMP IF SIGNED LESS THAN OR EQUAL.
Tests both the negative flag and the zero flag.
If both flags are clear, control passes to the
next sequential instruction. If either flag is set,
this instruction adds to the program counter
the offset between the end of this instruction
and the target label, effecting the jump. The
offset must be in the range of –128 to +127.
JLE
cadd
(11011010) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if N = 1 OR Z = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-19
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Table A-6. Instruction Set (Continued)
Operation Instruction Format
Mnemonic
JLT
JUMP IF SIGNED LESS THAN. Tests the
negative flag. If the flag is clear, control
passes to the next sequential instruction. If
the negative flag is set, this instruction adds
to the program counter the offset between the
end of this instruction and the target label,
effecting the jump. The offset must be in the
range of –128 to +127.
JLT
cadd
(11011110) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if N = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JNC
JUMP IF CARRY FLAG IS CLEAR. Tests the
carry flag. If the flag is set, control passes to
the next sequential instruction. If the carry
flag is clear, this instruction adds to the
program counter the offset between the end
of this instruction and the target label,
effecting the jump. The offset must be in the
range of –128 to +127.
JNC
cadd
(11010011) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if C = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JNE
JUMP IF NOT EQUAL. Tests the zero flag. If
the flag is set, control passes to the next
sequential instruction. If the zero flag is clear,
this instruction adds to the program counter
the offset between the end of this instruction
and the target label, effecting the jump. The
offset must be in the range of –128 to +127.
JNE
cadd
(11010111) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if Z = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-20
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
JNH
JUMP IF NOT HIGHER (UNSIGNED). Tests
both the zero flag and the carry flag. If the
carry flag is set and the zero flag is clear,
control passes to the next sequential
instruction. If either the carry flag is clear or
the zero flag is set, this instruction adds to the
program counter the offset between the end
of this instruction and the target label,
effecting the jump. The offset must be in
range of –128 to +127.
JNH
cadd
(11010001) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if C = 0 OR Z = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JNST
JUMP IF STICKY BIT FLAG IS CLEAR. Tests
the sticky bit flag. If the flag is set, control
passes to the next sequential instruction. If
the sticky bit flag is clear, this instruction adds
to the program counter the offset between the
end of this instruction and the target label,
effecting the jump. The offset must be in
range of –128 to +127.
JNST
cadd
(11010000) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if ST = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JNV
JUMP IF OVERFLOW FLAG IS CLEAR.
Tests the overflow flag. If the flag is set,
control passes to the next sequential
JNV
cadd
(11010101) (disp)
instruction. If the overflow flag is clear, this
instruction adds to the program counter the
offset between the end of this instruction and
the target label, effecting the jump. The offset
must be in range of –128 to +127.
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if V = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-21
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Table A-6. Instruction Set (Continued)
Operation Instruction Format
Mnemonic
JNVT
JUMP IF OVERFLOW-TRAP FLAG IS
CLEAR. Tests the overflow-trap flag. If the
flag is set, this instruction clears the flag and
passes control to the next sequential
JNVT
cadd
(11010100) (disp)
instruction. If the overflow-trap flag is clear,
this instruction adds to the program counter
the offset between the end of this instruction
and the target label, effecting the jump. The
offset must be in range of –128 to +127.
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if VT = 0 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
0
—
JST
JUMP IF STICKY BIT FLAG IS SET. Tests
the sticky bit flag. If the flag is clear, control
passes to the next sequential instruction. If
the sticky bit flag is set, this instruction adds
to the program counter the offset between the
end of this instruction and the target label,
effecting the jump. The offset must be in
range of –128 to +127.
JST
cadd
(11011000) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if ST = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
JV
JUMP IF OVERFLOW FLAG IS SET. Tests
the overflow flag. If the flag is clear, control
passes to the next sequential instruction. If
the overflow flag is set, this instruction adds
to the program counter the offset between the
end of this instruction and the target label,
effecting the jump. The offset must be in
range of –128 to +127.
JV
cadd
(11011101) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if V = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-22
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
JVT
JUMP IF OVERFLOW-TRAP FLAG IS SET.
Tests the overflow-trap flag. If the flag is clear,
control passes to the next sequential
instruction. If the overflow-trap flag is set, this
instruction clears the flag and adds to the
program counter the offset between the end
of this instruction and the target label,
effecting the jump. The offset must be in
range of –128 to +127.
JVT
cadd
(11011100) (disp)
NOTE: The displacement (disp) is sign-
extended to 16 bits.
if VT = 1 then
PC ← PC + 8-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
0
—
LCALL
LONG CALL. Pushes the contents of the
program counter (the return address) onto
the stack, then adds to the program counter
the offset between the end of this instruction
and the target label, effecting the call. The
offset must be in the range of –32,768 to
+32,767.
LCALL cadd
(11101111) (disp-low) (disp-high)
SP ← SP – 2
(SP) ← PC
PC ← PC + 16-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
LD
LOAD WORD. Loads the value of the source
word operand into the destination operand.
DEST, SRC
LD
wreg, waop
(DEST) ← (SRC)
(101000aa) (waop) (wreg)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
LDB
LOAD BYTE. Loads the value of the source
byte operand into the destination operand.
DEST, SRC
breg, baop
(101100aa) (baop) (breg)
LDB
(DEST) ← (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-23
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
LDBSE
LOAD BYTE SIGN-EXTENDED. Sign-
extends the value of the source short-
integer operand and loads it into the
destination integer operand.
DEST, SRC
LDBSE wreg, baop
(101111aa) (baop) (wreg)
(low byte DEST) ← (SRC)
if DEST.15 = 1 then
(high word DEST) ← 0FFH
else
(high word DEST) ← 0
end_if
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
LDBZE
LOAD BYTE ZERO-EXTENDED. Zero-
extends the value of the source byte operand
and loads it into the destination word
operand.
DEST, SRC
LDBZE wreg, baop
(101011aa) (baop) (wreg)
(low byte DEST) ← (SRC)
(high byte DEST) ← 0
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
LJMP
LONG JUMP. Adds to the program counter
the offset between the end of this instruction
and the target label, effecting the jump. The
offset must be in the range of –32,768 to
+32,767.
LJMP
cadd
(11100111) (disp-low) (disp-high)
PC ← PC + 16-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
A-24
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
MUL
MULTIPLY INTEGERS. Multiplies the source
DEST, SRC
lreg, waop
(2 operands) and destination integer operands, using
signed arithmetic, and stores the 32-bit result
into the destination long-integer operand.
The sticky bit flag is undefined after the
instruction is executed.
MUL
(11111110) (011011aa) (waop) (lreg)
(DEST) ← (DEST) × (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
MUL
MULTIPLY INTEGERS. Multiplies the two
DEST, SRC1, SRC2
lreg, wreg, waop
(11111110) (010011aa) (waop) (wreg) (lreg)
(3 operands) source integer operands, using signed
arithmetic, and stores the 32-bit result into
the destination long-integer operand. The
sticky bit flag is undefined after the instruction
is executed.
MUL
(DEST) ← (SRC1) × (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
MULB
MULTIPLY SHORT-INTEGERS. Multiplies
DEST, SRC
wreg, baop
(11111110) (011111aa) (baop) (wreg)
(2 operands) the source and destination short-integer
operands, using signed arithmetic, and stores
the 16-bit result into the destination integer
operand. The sticky bit flag is undefined after
the instruction is executed.
MULB
(DEST) ← (DEST) × (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
MULB
MULTIPLY SHORT-INTEGERS. Multiplies
DEST, SRC1, SRC2
wreg, breg, baop
(11111110) (010111aa) (baop) (breg) (wreg)
(3 operands) the two source short-integer operands,
using signed arithmetic, and stores the 16-bit
result into the destination integer operand.
The sticky bit flag is undefined after the
instruction is executed.
MULB
(DEST) ← (SRC1) × (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
A-25
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
MULU
MULTIPLY WORDS, UNSIGNED. Multiplies
DEST, SRC
lreg, waop
(2 operands) the source and destination word operands,
using unsigned arithmetic, and stores the 32-
bit result into the destination double-word
operand. The sticky bit flag is undefined after
the instruction is executed.
MULU
(011011aa) (waop) (lreg)
(DEST) ← (DEST) × (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
MULU
MULTIPLY WORDS, UNSIGNED. Multiplies
DEST, SRC1, SRC2
lreg, wreg, waop
(3 operands) the two source word operands, using
unsigned arithmetic, and stores the 32-bit
result into the destination double-word
operand. The sticky bit flag is undefined after
the instruction is executed.
MULU
(010011aa) (waop) (wreg) (lreg)
(DEST) ← (SRC1) × (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
MULUB
MULTIPLY BYTES, UNSIGNED. Multiplies
DEST, SRC
MULUB wreg, baop
(011111aa) (baop) (wreg)
(2 operands) the source and destination operands, using
unsigned arithmetic, and stores the word
result into the destination operand. The sticky
bit flag is undefined after the instruction is
executed.
(DEST) ← (DEST) × (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
MULUB
MULTIPLY BYTES, UNSIGNED. Multiplies
DEST, SRC1, SRC2
MULUB wreg, breg, baop
(3 operands) the two source byte operands, using
unsigned arithmetic, and stores the word
result into the destination operand. The sticky
bit flag is undefined after the instruction is
executed.
(010111aa) (baop) (breg) (wreg)
(DEST) ← (SRC1) × (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
?
A-26
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
NEG
NEGATE INTEGER. Negates the value of the
integer operand.
NEG
wreg
(DEST) ← – (DEST)
(00000011) (wreg)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
NEGB
NEGATE SHORT-INTEGER. Negates the
value of the short-integer operand.
NEGB
breg
(DEST) ← – (DEST)
(00010011) (breg)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
NOP
NO OPERATION. Does nothing. Control
passes to the next sequential instruction.
NOP
(11111101)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
NORML
NORMALIZE LONG-INTEGER. Normalizes
the source (leftmost) long-integer operand.
(That is, it shifts the operand to the left until
its most significant bit is “1” or until it has
performed 31 shifts). If the most significant
bit is still “0” after 31 shifts, the instruction
stops the process and sets the zero flag. The
instruction stores the actual number of shifts
performed in the destination (rightmost)
operand.
SRC, DEST
NORML lreg, breg
(00001111) (breg) (lreg)
(COUNT) ← 0
do while
(MSB (DEST) = 0) AND (COUNT) < 31)
(DEST) ← (DEST) × 2
(COUNT) ← (COUNT) + 1
end_while
PSW Flag Settings
Z
N
C
V
VT ST
✓
?
0
—
—
—
A-27
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Table A-6. Instruction Set (Continued)
Operation Instruction Format
Mnemonic
NOT
COMPLEMENT WORD. Complements the
value of the word operand (replaces each “1”
with a “0” and each “0” with a “1”).
NOT
wreg
(00000010) (wreg)
(DEST) ← NOT (DEST)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
NOTB
COMPLEMENT BYTE. Complements the
value of the byte operand (replaces each “1”
with a “0” and each “0” with a “1”).
NOTB
breg
(00010010) (breg)
(DEST) ← NOT (DEST)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
OR
LOGICAL OR WORDS. ORs the source word
operand with the destination word operand
and replaces the original destination operand
with the result. The result has a “1” in each bit
position in which either the source or
DEST, SRC
wreg, waop
(100000aa) (waop) (wreg)
OR
destination operand had a “1”.
(DEST) ← (DEST) OR (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
ORB
LOGICAL OR BYTES. ORs the source byte
operand with the destination byte operand
and replaces the original destination operand
with the result. The result has a “1” in each bit
position in which either the source or
DEST, SRC
breg, baop
(100100aa) (baop) (breg)
ORB
destination operand had a “1”.
(DEST) ← (DEST) OR (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
A-28
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
POP
POP WORD. Pops the word on top of the
stack and places it at the destination
operand.
POP
waop
(110011aa) (waop)
(DEST) ← (SP)
SP ← SP + 2
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
POPA
POP ALL. This instruction is used instead of
POPF, to support the eight additional
interrupts. It pops two words off the stack and
places the first word into the
POPA
(11110101)
INT_MASK1/WSR register pair and the
second word into the PSW/INT_MASK
register-pair. This instruction increments the
SP by 4. Interrupt calls cannot occur
immediately following this instruction.
INT_MASK1/WSR ← (SP)
SP ← SP + 2
PSW/INT_MASK ← (SP)
SP ← SP + 2
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
✓
✓
POPF
POP FLAGS. Pops the word on top of the
stack and places it into the PSW. Interrupt
calls cannot occur immediately following this
instruction.
POPF
(11110011)
(PSW)/INT_MASK ← (SP)
SP ← SP + 2
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
✓
✓
PUSH
PUSH WORD. Pushes the word operand
onto the stack.
PUSH
waop
SP ← SP – 2
(110010aa) (waop)
(SP) ← (DEST)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-29
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Table A-6. Instruction Set (Continued)
Operation Instruction Format
Mnemonic
PUSHA
PUSH ALL. This instruction is used instead of
PUSHF, to support the eight additional
interrupts. It pushes two words —
PSW/INT_MASK and INT_MASK1/WSR —
onto the stack.
PUSHA
(11110100)
This instruction clears the PSW, INT_MASK,
and INT_MASK1 registers and decrements
the SP by 4. Interrupt calls cannot occur
immediately following this instruction.
SP ← SP – 2
(SP) ← PSW/INT_MASK
PSW/INT_MASK ← 0
SP ← SP – 2
(SP) ← INT_MASK1/WSR
INT_MASK1 ← 0
PSW Flag Settings
Z
N
C
V
VT ST
0
0
0
0
0
0
PUSHF
PUSH FLAGS. Pushes the PSW onto the top
of the stack, then clears it. Clearing the PSW
disables interrupt servicing. Interrupt calls
cannot occur immediately following this
instruction.
PUSHF
(11110010)
SP ← SP – 2
(SP) ← PSW/INT_MASK
PSW/INT_MASK ← 0
PSW Flag Settings
Z
N
C
V
VT ST
0
0
0
0
0
0
RET
RETURN FROM SUBROUTINE. Pops the
PC off the top of the stack.
RET
PC ← (SP)
(11110000)
SP ← SP + 2
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-30
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
RST
RESET SYSTEM. Initializes the PSW to zero,
the PC to 2080H, and the pins and SFRs to
their reset values. Executing this instruction
causes the RESET# pin to be pulled low for
16 state times.
RST
(11111111)
SFR ← Reset Status
Pin ← Reset Status
PSW ← 0
PC ← 2080H
PSW Flag Settings
Z
N
C
V
VT ST
0
0
0
0
0
0
SCALL
SHORT CALL. Pushes the contents of the
program counter (the return address) onto
the stack, then adds to the program counter
the offset between the end of this instruction
and the target label, effecting the call. The
offset must be in the range of –1024 to
+1023.
SCALL cadd
(00101xxx) (disp-low)
NOTE: The displacement (disp) is sign-
extended to 16-bits.
SP ← SP – 2
(SP) ← PC
PC←PC +11-bit disp
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
SETC
SET CARRY FLAG. Sets the carry flag.
C ← 1
SETC
(11111001)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
1
—
—
—
A-31
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
SHL
SHIFT WORD LEFT. Shifts the destination
word operand to the left as many times as
specified by the count operand. The count
may be specified either as an immediate
SHL
wreg, #count
(00001001) (count) (wreg)
value in the range of 0 to 15 (0FH), inclusive, or
or as the content of any register (10H –
SHL
wreg, breg
0FFH) with a value in the range of 0 to 31
(1FH), inclusive. The right bits of the result
are filled with zeros. The last bit shifted out is
saved in the carry flag.
(00001001) (breg) (wreg)
Temp ← (COUNT)
do while Temp ≠ 0
C ← High order bit of (DEST)
(DEST) ← (DEST) × 2
Temp ← Temp – 1
end_while
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
SHLB
SHIFT BYTE LEFT. Shifts the destination
byte operand to the left as many times as
specified by the count operand. The count
may be specified either as an immediate
SHLB
breg, #count
(00011001) (count) (breg)
value in the range of 0 to 15 (0FH), inclusive, or
or as the content of any register (10H –
SHLB
breg, breg
0FFH) with a value in the range of 0 to 31
(1FH), inclusive. The right bits of the result
are filled with zeros. The last bit shifted out is
saved in the carry flag.
(00011001) (breg) (breg)
Temp ← (COUNT)
do while Temp ≠ 0
C ← High order bit of (DEST)
(DEST) ← (DEST) × 2
Temp ← Temp – 1
end_while
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
A-32
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
SHLL
SHIFT DOUBLE-WORD LEFT. Shifts the
destination double-word operand to the left
as many times as specified by the count
operand. The count may be specified either
SHLL
lreg, #count
(00001101) (count) (lreg)
as an immediate value in the range of 0 to 15 or
(0FH), inclusive, or as the content of any
SHLL
lreg, breg
register (10H – 0FFH) with a value in the
range of 0 to 31 (1FH), inclusive. The right
bits of the result are filled with zeros. The last
bit shifted out is saved in the carry flag.
(00001101) (breg) (lreg)
Temp ← (COUNT)
do while Temp ≠ 0
C ← High order bit of (DEST)
(DEST) ← (DEST) × 2
Temp ← Temp – 1
end_while
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
SHR
LOGICAL RIGHT SHIFT WORD. Shifts the
destination word operand to the right as
many times as specified by the count
SHR
wreg, #count
(00001000) (count) (wreg)
operand. The count may be specified either
as an immediate value in the range of 0 to 15 or
(0FH), inclusive, or as the content of any
SHR
wreg, breg
register (10H – 0FFH) with a value in the
range of 0 to 31 (1FH), inclusive. The left bits
of the result are filled with zeros. The last bit
shifted out is saved in the carry flag.
(00001000) (breg) (wreg)
NOTES: This instruction clears the
sticky bit flag at the beginning
of the instruction. If at any time
during the shift a “1” is shifted
into the carry flag and another
shift cycle occurs, the instruc-
tion sets the sticky bit flag.
Temp ← (COUNT)
do while Temp ≠ 0
C ← Low order bit of (DEST)
(DEST) ← (DEST)/2
Temp ← Temp – 1
end_while
In this operation, (DEST)/2 rep-
resents unsigned division.
PSW Flag Settings
Z
N
C
V
VT ST
✓
0
✓
0
—
✓
A-33
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
SHRA
ARITHMETIC RIGHT SHIFT WORD. Shifts
the destination word operand to the right as
many times as specified by the count
SHRA
wreg, #count
(00001010) (count) (wreg)
operand. The count may be specified either
as an immediate value in the range of 0 to 15 or
(0FH), inclusive, or as the content of any
SHRA
wreg, breg
register (10H – 0FFH) with a value in the
range of 0 to 31 (1FH), inclusive. If the
original high order bit value was “0,” zeros are
shifted in. If the value was “1,” ones are
shifted in. The last bit shifted out is saved in
the carry flag.
(00001010) (breg) (wreg)
NOTES: This instruction clears the
sticky bit flag at the beginning
of the instruction. If at any time
during the shift a “1” is shifted
into the carry flag and another
shift cycle occurs, the instruc-
tion sets the sticky bit flag.
Temp ← (COUNT)
do while Temp ≠ 0
C ← Low order bit of (DEST)
(DEST) ← (DEST)/2
Temp ← Temp – 1
end_while
In this operation, (DEST)/2 rep-
resents signed division.
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
0
—
✓
SHRAB
ARITHMETIC RIGHT SHIFT BYTE. Shifts the
destination byte operand to the right as many
times as specified by the count operand. The
count may be specified either as an
SHRAB breg, #count
(00011010) (count) (breg)
or
immediate value in the range of 0 to 15
(0FH), inclusive, or as the content of any
register (10H – 0FFH) with a value in the
range of 0 to 31 (1FH), inclusive. If the
original high order bit value was “0,” zeros are
shifted in. If the value was “1,” ones are
shifted in. The last bit shifted out is saved in
the carry flag.
SHRAB breg, breg
(00011010) (breg) (breg)
NOTES: This instruction clears the
sticky bit flag at the beginning
of the instruction. If at any time
during the shift a “1” is shifted
into the carry flag and another
shift cycle occurs, the instruc-
tion sets the sticky bit flag.
Temp ← (COUNT)
do while Temp ≠ 0
C = Low order bit of (DEST)
(DEST) ← (DEST)/2
Temp ← Temp – 1
end_while
In this operation, (DEST)/2 rep-
resents signed division.
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
0
—
✓
A-34
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
SHRAL
ARITHMETIC RIGHT SHIFT DOUBLE-
WORD. Shifts the destination double-word
operand to the right as many times as
specified by the count operand. The count
may be specified either as an immediate
value in the range of 0 to 15 (0FH), inclusive,
or as the content of any register (10H –
0FFH) with a value in the range of 0 to 31
(1FH), inclusive. If the original high order bit
value was “0,” zeros are shifted in. If the
value was “1,” ones are shifted in.
SHRAL lreg, #count
(00001110) (count) (lreg)
or
SHRAL lreg, breg
(00001110) (breg) (lreg)
NOTES: This instruction clears the
sticky bit flag at the beginning
of the instruction. If at any time
during the shift a “1” is shifted
into the carry flag and another
shift cycle occurs, the instruc-
tion sets the sticky bit flag.
Temp ← (COUNT)
do while Temp ≠ 0
C ← Low order bit of (DEST)
(DEST) ← (DEST)/2
Temp ← Temp – 1
end_while
In this operation, (DEST)/2 rep-
resents signed division.
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
0
—
✓
SHRB
LOGICAL RIGHT SHIFT BYTE. Shifts the
destination byte operand to the right as many
times as specified by the count operand. The
count may be specified either as an
SHRB
breg, #count
(00011000) (count) (breg)
immediate value in the range of 0 to 15
(0FH), inclusive, or as the content of any
register (10H – 0FFH) with a value in the
range of 0 to 31 (1FH), inclusive. The left bits
of the result are filled with zeros. The last bit
shifted out is saved in the carry flag.
or
SHRB
breg, breg
(00011000) (breg) (breg)
NOTES: This instruction clears the
sticky bit flag at the beginning
of the instruction. If at any time
during the shift a “1” is shifted
into the carry flag and another
shift cycle occurs, the instruc-
tion sets the sticky bit flag.
Temp ← (COUNT)
do while Temp ≠ 0
C ← Low order bit of (DEST)
(DEST) ← (DEST)/2
Temp ← Temp–1
end_while
In this operation, (DEST)/2 rep-
resents unsigned division.
PSW Flag Settings
Z
N
C
V
VT ST
✓
0
✓
0
—
✓
A-35
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
SHRL
LOGICAL RIGHT SHIFT DOUBLE-WORD.
Shifts the destination double-word operand to
the right as many times as specified by the
count operand. The count may be specified
SHRL
lreg, #count
(00001100) (count) (lreg)
either as an immediate value in the range of 0 or
to 15 (0FH), inclusive, or as the content of
SHRL
lreg, breg
any register (10H – 0FFH) with a value in the
range of 0 to 31 (1FH), inclusive. The left bits
of the result are filled with zeros. The last bit
shifted out is saved in the carry flag.
(00001100) (breg) (lreg)
NOTES: This instruction clears the
sticky bit flag at the beginning
of the instruction. If at any time
during the shift a “1” is shifted
into the carry flag and another
shift cycle occurs, the instruc-
tion sets the sticky bit flag.
Temp ← (COUNT)
do while Temp ≠ 0
C ← Low order bit of (DEST)
(DEST) ← (DEST)/2)
Temp ← Temp – 1
end_while
In this operation, (DEST)/2 rep-
resents unsigned division.
PSW Flag Settings
Z
N
C
V
VT ST
✓
0
✓
0
—
✓
SJMP
SHORT JUMP. Adds to the program counter
the offset between the end of this instruction
and the target label, effecting the jump. The
offset must be in the range of –1024 to
+1023, inclusive.
SJMP
cadd
(00100xxx) (disp-low)
PC ← PC + 11-bit disp
NOTE: The displacement (disp) is sign-
extended to 16 bits.
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
SKIP
TWO BYTE NO-OPERATION. Does nothing.
Control passes to the next sequential
instruction. This is actually a two-byte NOP in
which the second byte can be any value and
is simply ignored.
SKIP
breg
(00000000) (breg)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-36
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
ST
Operation
Instruction Format
STORE WORD. Stores the value of the
source (leftmost) word operand into the
destination (rightmost) operand.
SRC, DEST
wreg, waop
ST
(110000aa) (waop) (wreg)
(DEST) ← (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
STB
STORE BYTE. Stores the value of the source
(leftmost) byte operand into the destination
(rightmost) operand.
SRC, DEST
breg, baop
(110001aa) (baop) (breg)
STB
(DEST) ← (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
SUB
SUBTRACT WORDS. Subtracts the source
DEST, SRC
wreg, waop
(011010aa) (waop) (wreg)
(2 operands) word operand from the destination word
operand, stores the result in the destination
operand, and sets the carry flag as the
complement of borrow.
SUB
(DEST) ← (DEST) – (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
SUB
SUBTRACT WORDS. Subtracts the first
DEST, SRC1, SRC2
Dwreg, Swreg, waop
(010010aa) (waop) (Swreg) (Dwreg)
(3 operands) source word operand from the second, stores
SUB
the result in the destination operand, and sets
the carry flag as the complement of borrow.
(DEST) ← (SRC1) – (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
A-37
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Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
SUBB
SUBTRACT BYTES. Subtracts the source
DEST, SRC
breg, baop
(2 operands) byte operand from the destination byte
operand, stores the result in the destination
operand, and sets the carry flag as the
complement of borrow.
SUBB
(011110aa) (baop) (breg)
(DEST) ← (DEST) – (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
SUBB
SUBTRACT BYTES. Subtracts the first
DEST, SRC1, SRC2
Dbreg, Sbreg, baop
(010110aa) (baop) (Sbreg) (Dbreg)
(3 operands) source byte operand from the second, stores
the result in the destination operand, and sets
the carry flag as the complement of borrow.
SUBB
(DEST) ← (SRC1) – (SRC2)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
✓
✓
↑
—
SUBC
SUBTRACT WORDS WITH BORROW.
Subtracts the source word operand from the
destination word operand. If the carry flag
was clear, SUBC subtracts 1 from the result.
It stores the result in the destination operand
and sets the carry flag as the complement of
borrow.
DEST, SRC
wreg, waop
SUBC
(101010aa) (waop) (wreg)
(DEST) ← (DEST) – (SRC) – (1–C)
PSW Flag Settings
Z
N
C
V
VT ST
↓
✓
✓
✓
↑
—
SUBCB
SUBTRACT BYTES WITH BORROW.
Subtracts the source byte operand from the
destination byte operand. If the carry flag was
clear, SUBCB subtracts 1 from the result. It
stores the result in the destination operand
and sets the carry flag as the complement of
borrow.
DEST, SRC
SUBCB breg, baop
(101110aa) (baop) (breg)
(DEST) ← (DEST) – (SRC) – (1–C)
PSW Flag Settings
Z
N
C
V
VT ST
↓
✓
✓
✓
↑
—
A-38
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INSTRUCTION SET REFERENCE
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
TIJMP
TABLE INDIRECT JUMP. Causes execution
to continue at an address selected from a
table of addresses.
TIJMP
TBASE, [INDEX], #MASK
(11100010) [INDEX] (#MASK) (TBASE)
The first word register, TBASE, contains the
16-bit address of the beginning of the jump
table. TBASE can be located in RAM up to
FEH without windowing or above FFH with
windowing. The jump table itself can be
placed at any nonreserved memory location
on a word boundary.
NOTE: TIJMP multiplies OFFSET by two
to provide for word alignment of
the jump table.
The second word register, INDEX, contains
the 16-bit address that points to a register
containing a 7-bit value. This value is used to
calculate the offset into the jump table. Like
TBASE, INDEX can be located in RAM up to
FEH without windowing or above FFH with
windowing. Note that the 16-bit address
contained in INDEX is absolute; it disregards
any windowing that may be in effect when the
TIJMP instruction is executed.
The byte operand, #MASK, is 7-bit immediate
data to mask INDEX. #MASK is ANDed with
INDEX to determine the offset (OFFSET).
OFFSET is multiplied by two, then added to
the base address (TBASE) to determine the
destination address (DEST X).
[INDEX] AND #MASK = OFFSET
(2 × OFFSET) + TBASE = DEST X
PC ← (DEST X)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
TRAP
SOFTWARE TRAP. This instruction causes
an interrupt call that is vectored through
location 2010H. The operation of this
instruction is not affected by the state of the
interrupt enable flag (I) in the PSW. Interrupt
calls cannot occur immediately following this
instruction.
TRAP
(11110111)
NOTE: This instruction is not supported
by assemblers. The TRAP
SP ← SP – 2
(SP) ← PC
instruction is intended for use by
development tools. These tools
may not support user-application
of this instruction.
PC ← (2010H)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
A-39
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8XC196MC, MD, MH USER’S MANUAL
Table A-6. Instruction Set (Continued)
Mnemonic
Operation
Instruction Format
XCH
EXCHANGE WORD. Exchanges the value of
the source word operand with that of the
destination word operand.
DEST, SRC
wreg, waop
XCH
(00000100) (waop) (wreg) direct
(00001011) (waop) (wreg) indexed
(DEST) ↔ (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
XCHB
EXCHANGE BYTE. Exchanges the value of
the source byte operand with that of the
destination byte operand.
DEST, SRC
XCHB
breg, baop
(00010100) (baop) (breg) direct
(00011011) (baop) (breg) indexed
(DEST) ↔ (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
—
—
—
—
—
—
XOR
LOGICAL EXCLUSIVE-OR WORDS. XORs
the source word operand with the destination
word operand and stores the result in the
destination operand. The result has ones in
the bit positions in which either operand (but
not both) had a “1” and zeros in all other bit
positions.
DEST, SRC
XOR
wreg, waop
(100001aa) (waop) (wreg)
(DEST) ← (DEST) XOR (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
XORB
LOGICAL EXCLUSIVE-OR BYTES. XORs
the source byte operand with the destination
byte operand and stores the result in the
destination operand. The result has ones in
the bit positions in which either operand (but
not both) had a “1” and zeros in all other bit
positions.
DEST, SRC
breg, baop
(100101aa) (baop) (breg)
XORB
(DEST) ← (DEST) XOR (SRC)
PSW Flag Settings
Z
N
C
V
VT ST
✓
✓
0
0
—
—
A-40
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INSTRUCTION SET REFERENCE
Table A-7 lists the instruction opcodes, in hexadecimal order, along with the corresponding in-
struction mnemonics.
Table A-7. Instruction Opcodes
Hex Code
Instruction Mnemonic
00
01
SKIP
CLR
02
NOT
03
NEG
04
XCH Direct
DEC
05
06
EXT
07
INC
08
SHR
09
SHL
0A
SHRA
0B
XCH Indexed
SHRL
0C
0D
SHLL
0E
SHRAL
0F
NORML
Reserved
CLRB
10
11
12
NOTB
13
NEGB
14
XCHB Direct
DECB
15
16
EXTB
17
INCB
18
SHRB
19
SHLB
1A
SHRAB
1B
XCHB Indexed
Reserved
SJMP
1C–1F
20–27
28–2F
30–37
38–3F
40
SCALL
JBC
JBS
AND Direct (3 ops)
AND Immediate (3 ops)
AND Indirect (3 ops)
AND Indexed (3 ops)
ADD Direct (3 ops)
41
42
43
44
A-41
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8XC196MC, MD, MH USER’S MANUAL
Table A-7. Instruction Opcodes (Continued)
Instruction Mnemonic
Hex Code
45
46
47
48
49
4A
4B
4C
4D
4E
4F
50
51
52
53
54
55
56
57
58
59
5A
5B
5C
5D
5E
5F
60
61
62
63
64
65
66
67
68
69
6A
6B
6C
6D
ADD Immediate (3 ops)
ADD Indirect (3 ops)
ADD Indexed (3 ops)
SUB Direct (3 ops)
SUB Immediate (3 ops)
SUB Indirect (3 ops)
SUB Indexed (3 ops)
MULU Direct (3 ops)
MULU Immediate (3 ops)
MULU Indirect (3 ops)
MULU Indexed (3 ops)
ANDB Direct (3 ops)
ANDB Immediate (3 ops)
ANDB Indirect (3 ops)
ANDB Indexed (3 ops)
ADDB Direct (3 ops)
ADDB Immediate (3 ops)
ADDB Indirect (3 ops)
ADDB Indexed (3 ops)
SUBB Direct (3 ops)
SUBB Immediate (3 ops)
SUBB Indirect (3 ops)
SUBB Indexed (3 ops)
MULUB Direct (3 ops)
MULUB Immediate (3 ops)
MULUB Indirect (3 ops)
MULUB Indexed (3 ops)
AND Direct (2 ops)
AND Immediate (2 ops)
AND Indirect (2 ops)
AND Indexed (2 ops)
ADD Direct (2 ops)
ADD Immediate (2 ops)
ADD Indirect (2 ops)
ADD Indexed (2 ops)
SUB Direct (2 ops)
SUB Immediate (2 ops)
SUB Indirect (2 ops)
SUB Indexed (2 ops)
MULU Direct (2 ops)
MULU Immediate (2 ops)
A-42
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Table A-7. Instruction Opcodes (Continued)
Instruction Mnemonic
Hex Code
6E
6F
70
71
72
73
74
75
76
77
78
79
7A
7B
7C
7D
7E
7F
80
81
82
83
84
85
86
87
88
89
8A
8B
8C
8D
8E
8F
90
91
92
93
94
95
96
MULU Indirect (2 ops)
MULU Indexed (2 ops)
ANDB Direct (2 ops)
ANDB Immediate (2 ops)
ANDB Indirect (2 ops)
ANDB Indexed (2 ops)
ADDB Direct (2 ops)
ADDB Immediate (2 ops)
ADDB Indirect (2 ops)
ADDB Indexed (2 ops)
SUBB Direct (2 ops)
SUBB Immediate (2 ops)
SUBB Indirect (2 ops)
SUBB Indexed (2 ops)
MULUB Direct (2 ops)
MULUB Immediate (2 ops)
MULUB Indirect (2 ops)
MULUB Indexed (2 ops)
OR Direct
OR Immediate
OR Indirect
OR Indexed
XOR Direct
XOR Immediate
XOR Indirect
XOR Indexed
CMP Direct
CMP Immediate
CMP Indirect
CMP Indexed
DIVU Direct
DIVU Immediate
DIVU Indirect
DIVU Indexed
ORB Direct
ORB Immediate
ORB Indirect
ORB Indexed
XORB Direct
XORB Immediate
XORB Indirect
A-43
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Table A-7. Instruction Opcodes (Continued)
Instruction Mnemonic
Hex Code
97
98
XORB Indexed
CMPB Direct
99
CMPB Immediate
CMPB Indirect
CMPB Indexed
DIVUB Direct
9A
9B
9C
9D
9E
9F
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
AA
AB
AC
AD
AE
AF
B0
B1
B2
B3
B4
B5
B6
B7
B8
B9
BA
BB
BC
BD
BE
BF
DIVUB Immediate
DIVUB Indirect
DIVUB Indexed
LD Direct
LD Immediate
LD Indirect
LD Indexed
ADDC Direct
ADDC Immediate
ADDC Indirect
ADDC Indexed
SUBC Direct
SUBC Immediate
SUBC Indirect
SUBC Indexed
LDBZE Direct
LDBZE Immediate
LDBZE Indirect
LDBZE Indexed
LDB Direct
LDB Immediate
LDB Indirect
LDB Indexed
ADDCB Direct
ADDCB Immediate
ADDCB Indirect
ADDCB Indexed
SUBCB Direct
SUBCB Immediate
SUBCB Indirect
SUBCB Indexed
LDBSE Direct
LDBSE Immediate
LDBSE Indirect
LDBSE Indexed
A-44
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INSTRUCTION SET REFERENCE
Table A-7. Instruction Opcodes (Continued)
Instruction Mnemonic
Hex Code
C0
C1
C2
C3
C4
C5
C6
C7
C8
C9
CA
CB
CC
CD
CE
CF
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
DA
DB
DC
DD
DE
DF
E0
ST Direct
BMOV
ST Indirect
ST Indexed
STB Direct
CMPL
STB Indirect
STB Indexed
PUSH Direct
PUSH Immediate
PUSH Indirect
PUSH Indexed
POP Direct
BMOVI
POP Indirect
POP Indexed
JNST
JNH
JGT
JNC
JNVT
JNV
JGE
JNE
JST
JH
JLE
JC
JVT
JV
JLT
JE
DJNZ
E1
DJNZW
TIJMP
E2
E3
BR Indirect
Reserved
DPTS
E4–EB
EC
ED
EE
EF
EPTS
Reserved (Note 1)
LCALL
A-45
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8XC196MC, MD, MH USER’S MANUAL
Table A-7. Instruction Opcodes (Continued)
Instruction Mnemonic
Hex Code
F0
F2
F3
F4
F5
F6
F7
F8
F9
FA
FB
FC
FD
FE
FF
RET
PUSHF
POPF
PUSHA
POPA
IDLPD
TRAP
CLRC
SETC
DI
EI
CLRVT
NOP
DIV/DIVB/MUL/MULB (Note 2)
RST
NOTES:
1. This opcode is reserved, but it does not generate an unimplemented opcode interrupt.
2. Signed multiplication and division are two-byte instructions. For each signed instruction, the
first byte is “FE” and the second is the opcode of the corresponding unsigned instruction. For
example, the opcode for MULU (3 operands) direct is “4C,” so the opcode for MUL (3 oper-
ands) direct is “FE 4C.”
A-46
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Table A-8 lists instructions along with their lengths and opcodes for each applicable addressing
mode. A dash (—) in any column indicates “not applicable.”
Table A-8. Instruction Lengths and Hexadecimal Opcodes
Arithmetic (Group I)
Indexed
(Note 1)
Direct
Immediate
Indirect
Mnemonic
Length
Length Opcode Length Opcode Length Opcode
Opcode
S/L
ADD (2 ops)
3
4
3
4
3
3
2
2
3
3
3
2
2
2
2
2
2
3
4
3
4
3
3
64
44
74
54
A4
B4
01
11
4
5
65
45
75
55
A5
B5
—
—
89
99
—
—
—
—
—
—
—
69
49
79
59
A9
B9
3
4
66
46
76
56
A6
B6
—
4/5
5/6
4/5
5/6
4/5
4/5
—
67
47
77
57
A7
B7
—
ADD (3 ops)
ADDB (2 ops)
ADDB (3 ops)
ADDC
3
3
4
4
4
3
ADDCB
CLR
3
3
—
—
4
—
—
3
CLRB
—
—
—
CMP
88
98
C5
05
15
06
16
07
17
68
48
78
58
A8
B8
8A
9A
—
4/5
4/5
—
8B
9B
—
CMPB
3
3
CMPL
—
—
—
—
—
—
—
4
—
—
—
—
—
—
—
3
DEC
—
—
—
DECB
—
—
—
EXT
—
—
—
EXTB
—
—
—
INC
—
—
—
INCB
—
—
—
SUB (2 ops)
SUB (3 ops)
SUBB (2 ops)
SUBB (3 ops)
SUBC
6A
4A
7A
5A
AA
BA
4/5
5/6
4/5
5/6
4/5
4/5
6B
4B
7B
5B
AB
BB
5
4
3
3
4
4
4
3
SUBCB
NOTES:
3
3
1. For indexed instructions, the first column lists instruction lengths as S/L, where S is the short-indexed
instruction length and L is the long-indexed instruction length.
2. For the SCALL and SJMP instructions, the three least-significant bits of the opcode are concatenated
with the eight bits to form an 11-bit, two’s complement offset.
A-47
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Table A-8. Instruction Lengths and Hexadecimal Opcodes (Continued)
Arithmetic (Group II)
Indexed
(Note 1)
Direct
Immediate
Indirect
Mnemonic
Length
Length Opcode Length Opcode Length Opcode
Opcode
S/L
DIV
4
4
3
3
4
5
4
5
3
4
3
4
FE 8C
FE 9C
8C
5
4
4
3
5
6
4
5
4
5
3
4
FE 8D
FE 9D
8D
4
4
3
3
4
5
4
5
3
4
3
4
FE 8E
FE 9E
8E
5/6
5/6
4/5
4/5
5/6
6/7
5/6
6/7
4/5
5/6
4/5
5/6
FE 8F
FE 9F
8F
DIVB
DIVU
DIVUB
9C
9D
9E
9F
MUL (2 ops)
MUL (3 ops)
MULB (2 ops)
MULB (3 ops)
MULU (2 ops)
MULU (3 ops)
MULUB (2 ops)
MULUB (3 ops)
FE 6C
FE 4C
FE 7C
FE 5C
6C
FE 6D
FE 4D
FE 7D
FE 5D
6D
FE 6E
FE 4E
FE 7E
FE 5E
6E
FE 6F
FE 4F
FE 7F
FE 5F
6F
4C
4D
4E
4F
7C
7D
7E
7F
5C
5D
5E
5F
Logical
Indexed
(Note 1)
Direct
Immediate
Indirect
Mnemonic
Length
Length Opcode Length Opcode Length Opcode
Opcode
S/L
AND (2 ops)
AND (3 ops)
ANDB (2 ops)
ANDB (3 ops)
NEG
3
4
3
4
2
2
2
2
3
3
3
3
60
40
70
50
03
13
02
12
80
90
84
94
4
5
61
41
71
51
—
—
—
—
81
91
85
95
3
4
62
42
72
52
—
—
—
—
82
92
86
96
4/5
5/6
4/5
5/6
—
63
43
73
53
—
—
—
—
83
93
87
97
3
3
4
4
—
—
—
—
4
—
—
—
—
3
NEGB
—
NOT
—
NOTB
—
OR
4/5
4/5
4/5
4/5
ORB
3
3
XOR
4
3
XORB
3
3
NOTES:
1. For indexed instructions, the first column lists instruction lengths as S/L, where S is the short-indexed
instruction length and L is the long-indexed instruction length.
2. For the SCALL and SJMP instructions, the three least-significant bits of the opcode are concatenated
with the eight bits to form an 11-bit, two’s complement offset.
A-48
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Table A-8. Instruction Lengths and Hexadecimal Opcodes (Continued)
Stack
Indexed
(Note 1)
Direct
Immediate
Indirect
Mnemonic
Length
Length Opcode Length Opcode Length Opcode
Opcode
S/L
POP
2
1
1
2
1
1
CC
F5
F3
C8
F4
F2
—
—
—
3
—
—
—
C9
—
—
2
CE
—
3/4
—
CF
—
POPA
—
—
2
POPF
—
—
—
PUSH
PUSHA
PUSHF
CA
—
3/4
—
CB
—
—
—
—
—
—
—
—
Data
Indexed
(Note 1)
Direct
Immediate
Indirect
Mnemonic
Length
Length Opcode Length Opcode Length Opcode
Opcode
S/L
BMOV
BMOVI
LD
—
—
3
—
—
—
—
4
—
—
3
3
C1
CD
A2
B2
BE
AE
C2
C6
—
—
—
—
—
A0
B0
BC
AC
C0
C4
04
14
A1
B1
BD
AD
—
3
4/5
4/5
4/5
4/5
4/5
4/5
4/5
4/5
A3
B3
BF
AF
C3
C7
0B
1B
LDB
3
3
3
LDBSE
LDBZE
ST
3
3
3
3
3
3
3
—
—
—
—
3
STB
3
—
3
XCH
3
—
—
—
XCHB
3
—
—
Jump
Indexed
(Note 1)
Direct
Immediate
Indirect
Mnemonic
Length
Length Opcode Length Opcode Length Opcode
Opcode
S/L
BR
—
—
—
4
—
—
—
E2
—
—
—
4
—
—
—
E2
2
E3
—
—
—
—
—
E7
LJMP
—
—
—
—/3
2/—
—/4
SJMP (Note 2)
TIJMP
20–27
E2
NOTES:
1. For indexed instructions, the first column lists instruction lengths as S/L, where S is the short-indexed
instruction length and L is the long-indexed instruction length.
2. For the SCALL and SJMP instructions, the three least-significant bits of the opcode are concatenated
with the eight bits to form an 11-bit, two’s complement offset.
A-49
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Table A-8. Instruction Lengths and Hexadecimal Opcodes (Continued)
Call
Indexed
(Note 1)
Direct
Immediate
Indirect
Mnemonic
Length Opcode Length Opcode Length Opcode Length Opcode
LCALL
—
—
—
1
—
—
—
F7
—
—
—
—
—
—
—
—
—
1
—
F0
—
—
3
—
2
EF
—
RET
SCALL (Note 2)
TRAP
—
—
28–2F
—
—
Conditional Jump
Indexed
(Note 1)
Direct
Immediate
Indirect
Mnemonic
Length
S/L
Length Opcode Length Opcode Length Opcode
Opcode
DJNZ
DJNZW
JBC
JBS
JC
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
3/—
3/—
3/—
3/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
2/—
E0
E1
30–37
38–3F
DB
DF
JE
JGE
JGT
JH
D6
D2
D9
JLE
DA
DE
D3
JLT
JNC
JNE
JNH
JNST
JNV
JNVT
JST
D7
D1
D0
D5
D4
D8
JV
DD
DC
JVT
NOTES:
1. For indexed instructions, the first column lists instruction lengths as S/L, where S is the short-indexed
instruction length and L is the long-indexed instruction length.
2. For the SCALL and SJMP instructions, the three least-significant bits of the opcode are concatenated
with the eight bits to form an 11-bit, two’s complement offset.
A-50
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Table A-8. Instruction Lengths and Hexadecimal Opcodes (Continued)
Shift
Direct
Immediate
Indirect
Indexed
Mnemonic
NORML
Length Opcode Length Opcode Length Opcode Length Opcode
3
3
3
3
3
3
3
3
3
3
0F
09
19
0D
08
0A
1A
0E
18
0C
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
SHL
SHLB
SHLL
SHR
SHRA
SHRAB
SHRAL
SHRB
SHRL
Special
Immediate
Length Opcode Length Opcode Length Opcode Length Opcode
Direct
Indirect
Indexed
Mnemonic
CLRC
CLRVT
DI
1
1
F8
FC
FA
FB
—
—
—
—
—
1
—
—
—
—
F6
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
1
EI
1
IDLPD
NOP
RST
—
1
FD
FF
F9
00
—
—
—
—
1
SETC
SKIP
1
2
PTS
Immediate
Length Opcode Length Opcode Length Opcode Length Opcode
Direct
Indirect
Indexed
Mnemonic
DPTS
1
1
EC
ED
—
—
—
—
—
—
—
—
—
—
—
—
EPTS
NOTES:
1. For indexed instructions, the first column lists instruction lengths as S/L, where S is the short-indexed
instruction length and L is the long-indexed instruction length.
2. For the SCALL and SJMP instructions, the three least-significant bits of the opcode are concatenated
with the eight bits to form an 11-bit, two’s complement offset.
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Table A-9 lists instructions alphabetically within groups, along with their execution times, ex-
pressed in state times.
Table A-9. Instruction Execution Times (in State Times)
Arithmetic (Group I)
Indirect
Normal Autoinc.
Reg. Mem. Reg. Mem. Reg. Mem. Reg. Mem.
Indexed
Mnemonic
Direct
Immed.
Short
Long
ADD (2 ops)
4
5
4
5
4
4
3
3
4
4
7
3
3
4
4
3
3
4
5
4
5
4
4
5
6
6
7
8
10
8
7
8
9
11
9
6
7
8
10
8
7
8
9
11
9
ADD (3 ops)
ADDB (2 ops)
ADDB (3 ops)
ADDC
4
6
7
6
7
5
7
10
8
8
11
9
7
10
8
8
11
9
5
6
7
6
7
ADDCB
CLR
4
6
8
7
9
6
8
7
9
—
—
5
—
—
6
—
—
8
—
—
7
—
—
9
—
—
6
—
—
8
—
—
7
—
—
9
CLRB
CMP
CMPB
4
6
8
7
9
6
8
7
9
CMPL
—
—
—
—
—
—
—
5
—
—
—
—
—
—
—
6
—
—
—
—
—
—
—
8
—
—
—
—
—
—
—
7
—
—
—
—
—
—
—
9
—
—
—
—
—
—
—
6
—
—
—
—
—
—
—
8
—
—
—
—
—
—
—
7
—
—
—
—
—
—
—
9
DEC
DECB
EXT
EXTB
INC
INCB
SUB (2 ops)
SUB (3 ops)
SUBB (2 ops)
SUBB (3 ops)
SUBC
6
7
10
8
8
11
9
7
10
8
8
11
9
4
6
7
6
7
5
7
10
8
8
11
9
7
10
8
8
11
9
5
6
7
6
7
SUBCB
4
6
8
7
9
6
8
7
9
NOTE: The column entitled “Reg.” lists the instruction execution times for accesses to the register file or
peripheral SFRs. The column entitled “Mem.” lists the instruction execution times for accesses to
all memory-mapped registers, I/O, or memory. See Table 4-1 on page 4-2 for address information.
A-52
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Table A-9. Instruction Execution Times (in State Times) (Continued)
Arithmetic (Group II)
Indirect
Indexed
Mnemonic
Direct
Immed.
Normal
Autoinc.
Short
Long
Reg. Mem. Reg. Mem. Reg. Mem. Reg. Mem.
DIV
26
18
24
16
16
16
12
12
14
14
10
10
27
18
25
16
17
17
12
12
15
15
10
10
28
20
26
18
18
18
14
14
16
16
12
12
31
23
29
21
21
21
17
17
19
19
15
15
29
21
27
19
19
19
15
15
17
17
13
13
32
24
30
22
22
22
18
18
19
19
15
15
29
21
27
19
19
19
15
15
17
17
12
12
32
24
30
22
22
22
18
18
20
20
16
16
30
22
28
20
20
20
16
16
18
18
14
14
33
25
31
23
23
23
19
19
21
21
17
17
DIVB
DIVU
DIVUB
MUL (2 ops)
MUL (3 ops)
MULB (2 ops)
MULB (3 ops)
MULU (2 ops)
MULU (3 ops)
MULUB (2 ops)
MULUB (3 ops)
Logical
Indirect
Normal Autoinc.
Reg. Mem. Reg. Mem. Reg. Mem. Reg. Mem.
Indexed
Mnemonic
Direct
Immed.
Short
Long
AND (2 ops)
AND (3 ops)
ANDB (2 ops)
ANDB (3 ops)
NEG
4
5
4
5
3
3
3
3
4
4
4
4
5
6
6
7
8
10
8
7
8
9
11
9
6
7
8
10
8
7
8
9
11
9
4
6
7
6
7
5
7
10
—
—
—
—
8
8
11
—
—
—
—
9
7
10
—
—
—
—
8
8
11
—
—
—
—
9
—
—
—
—
5
—
—
—
—
6
—
—
—
—
7
—
—
—
—
6
—
—
—
—
7
NEGB
NOT
NOTB
OR
ORB
4
6
8
7
9
6
8
7
9
XOR
5
6
8
7
9
6
8
7
9
XORB
4
6
8
7
9
6
8
7
9
NOTE: The column entitled “Reg.” lists the instruction execution times for accesses to the register file or
peripheral SFRs. The column entitled “Mem.” lists the instruction execution times for accesses to
all memory-mapped registers, I/O, or memory. See Table 4-1 on page 4-2 for address information.
A-53
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8XC196MC, MD, MH USER’S MANUAL
Table A-9. Instruction Execution Times (in State Times) (Continued)
Stack (Register)
Indirect
Normal Autoinc.
Reg. Mem. Reg. Mem. Reg. Mem. Reg. Mem.
Indexed
Mnemonic
Direct
Immed.
Short
Long
POP
8
12
7
—
—
—
7
10
—
—
9
12
—
—
12
—
—
11
—
—
10
—
—
13
—
—
13
—
—
11
—
—
10
—
—
13
—
—
13
—
—
12
—
—
11
—
—
14
—
—
14
—
—
POPA
POPF
PUSH
6
PUSHA
PUSHF
12
6
—
—
—
—
Stack (Memory)
Indirect
Indexed
Mnemonic
Direct
Immed.
Normal
Autoinc.
Short
Long
Reg. Mem. Reg. Mem. Reg. Mem. Reg. Mem.
POP
11
18
10
8
—
—
—
9
13
—
—
11
—
—
15
—
—
14
—
—
14
—
—
12
—
—
16
—
—
15
—
—
14
—
—
12
—
—
16
—
—
15
—
—
15
—
—
13
—
—
17
—
—
16
—
—
POPA
POPF
PUSH
PUSHA
PUSHF
18
8
—
—
NOTE: The column entitled “Reg.” lists the instruction execution times for accesses to the register file or
peripheral SFRs. The column entitled “Mem.” lists the instruction execution times for accesses to
all memory-mapped registers, I/O, or memory. See Table 4-1 on page 4-2 for address information.
A-54
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INSTRUCTION SET REFERENCE
Table A-9. Instruction Execution Times (in State Times) (Continued)
Data
Mnemonic
BMOV
Indirect
register/register
memory/register
memory/memory
6 + 8 per word
6 + 11 per word
6 + 14 per word
BMOVI
register/register
memory/register
memory/memory
7 + 8 per word + 14 per interrupt
7 + 11 per word + 14 per interrupt
7 + 14 per word + 14 per interrupt
Indirect
Indexed
Mnemonic
Direct
Immed.
Normal
Autoinc.
Short
Long
Reg. Mem. Reg. Mem. Reg. Mem. Reg. Mem.
LD
4
4
4
4
4
4
5
5
5
4
5
5
8
8
6
6
8
8
6
6
6
6
6
6
8
8
9
9
7
7
7
7
7
7
9
9
10
10
10
10
10
10
14
14
LDB
LDBSE
LDBZE
ST
4
5
8
6
8
9
4
5
8
6
8
9
—
—
—
—
5
8
6
9
9
STB
5
8
6
8
9
XCH
XCHB
—
—
—
—
—
—
—
—
13
13
Jump
Indirect
Indexed
Mnemonic
Direct
Immed.
Normal
Autoinc.
Short
Long
BR
—
—
—
—
—
—
7
7
—
—
7
—
7
LJMP
SJMP
TIJMP
—
—
—
—
—
register/register
memory/register
memory/memory
15
18
21
—
—
—
—
—
Call (Register)
Indirect
Indexed
Mnemonic
Direct
Immed.
Normal
Autoinc.
Short
Long
LCALL
—
—
—
16
—
—
—
—
—
11
—
—
—
—
—
—
—
—
—
—
11
—
11
—
RET
SCALL
TRAP
NOTE: The column entitled “Reg.” lists the instruction execution times for accesses to the register file or
peripheral SFRs. The column entitled “Mem.” lists the instruction execution times for accesses to
all memory-mapped registers, I/O, or memory. See Table 4-1 on page 4-2 for address information.
A-55
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8XC196MC, MD, MH USER’S MANUAL
Table A-9. Instruction Execution Times (in State Times) (Continued)
Call (Memory)
Indirect
Indexed
Mnemonic
Direct
Immed.
Normal
—
Autoinc.
Short
—
Long
LCALL
—
—
—
—
—
—
13
RET
14
—
—
13
—
SCALL
TRAP
—
—
—
—
—
—
—
—
—
18
Conditional Jump
Mnemonic
Short-Indexed
DJNZ
DJNZW
JBC
JBS
JC
5 (jump not taken), 9 (jump taken)
6 (jump not taken), 10 (jump taken)
5 (jump not taken), 9 (jump taken)
5 (jump not taken), 9 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
4 (jump not taken), 8 (jump taken)
JE
JGE
JGT
JH
JLE
JLT
JNC
JNE
JNH
JNST
JNV
JNVT
JST
JV
JVT
NOTE: The column entitled “Reg.” lists the instruction execution times for accesses to the register file or
peripheral SFRs. The column entitled “Mem.” lists the instruction execution times for accesses to
all memory-mapped registers, I/O, or memory. See Table 4-1 on page 4-2 for address information.
A-56
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INSTRUCTION SET REFERENCE
Table A-9. Instruction Execution Times (in State Times) (Continued)
Shift
Mnemonic
NORML
Direct
8 + 1 per shift (9 for 0 shift)
6 + 1 per shift (7 for 0 shift)
6 + 1 per shift (7 for 0 shift)
7 + 1 per shift (8 for 0 shift)
6 + 1 per shift (7 for 0 shift)
6 + 1 per shift (7 for 0 shift)
6 + 1 per shift (7 for 0 shift)
7 + 1 per shift (8 for 0 shift)
6 + 1 per shift (7 for 0 shift)
7 + 1 per shift (8 for 0 shift)
SHL
SHLB
SHLL
SHR
SHRA
SHRAB
SHRAL
SHRB
SHRL
Special
Indirect
Autoinc.
Indexed
Mnemonic
Direct
Immed.
Normal
Short
Long
CLRC
CLRVT
DI
2
2
2
2
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
EI
IDLPD
Valid key
Invalid key
—
—
12
28
—
—
—
—
—
—
—
—
NOP
2
4
2
3
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
RST
SETC
SKIP
PTS
Indirect
Indexed
Mnemonic
Direct
Immed.
Normal
Autoinc.
Short
Long
DPTS
EPTS
2
2
—
—
—
—
—
—
—
—
—
—
NOTE: The column entitled “Reg.” lists the instruction execution times for accesses to the register file or
peripheral SFRs. The column entitled “Mem.” lists the instruction execution times for accesses to
all memory-mapped registers, I/O, or memory. See Table 4-1 on page 4-2 for address information.
A-57
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B
Signal Descriptions
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APPENDIX B
SIGNAL DESCRIPTIONS
This appendix provides reference information for the pin functions of the 8XC196MC,
8XC196MD, and 8XC196MH.
B.1 SIGNAL NAME CHANGES
The names of some 8XC196MC and 8XC196MD signals have been changed for consistency
®
with other MCS 96 microcontrollers. Table B-1 lists the old and new names.
Table B-1. Signal Name Changes
Name in 8XC196MC User’s Manual
AGND
New Name
ANGND
EPAx
CAPCOMPx
COMPAREx
COMPx
B.2 FUNCTIONAL GROUPINGS OF SIGNALS
Tables B-2, B-3, and B-4 list the signals for the 8XC196MC, 8XC196MD, and 8XC196MH re-
spectively, grouped by function. A diagram of each package that is currently available shows the
pin location of each signal.
NOTE
The datasheets are revised more frequently than this manual. As new packages
are supported, the pin-out diagrams will be added to the datasheets first. If
your package type is not shown in this appendix, refer to the latest datasheet to
find the pin locations.
B-1
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8XC196MC, MD, MH USER’S MANUAL
Table B-2. 8XC196MC Signals Arranged by Functional Categories
Address & Data
AD15:0
Programming Control
AINC#
Input/Output
P0.7:0/ACH7:0
P1.0/ACH8
P1.1/ACH9
P1.2/ACH10/T1CLK
P1.3/ACH11/T1DIR
P1.4/ACH12
P2.3:0/EPA3:0
P2.6:4/COMP2:0
P2.7/COMP3
P3.7:0
Input/Output (Cont’d)
P6.5/WG3
CPVER
P6.6/PWM0
Bus Control & Status
ALE/ADV#
BHE#/WRH#
BUSWIDTH
INST
PACT#
P6.7/PWM1
PALE#
PBUS.15:0
PMODE.3:0
PROG#
READY
PVER
RD#
WR#/WRL#
Processor Control
CLKOUT
EA#
P4.7:0
Power & Ground
P5.1
ANGND
VCC
EXTINT
NMI
P5.7:0
P6.0/WG1#
P6.1/WG1
VPP
ONCE#
VREF
VSS
RESET#
XTAL1
P6.2/WG2#
P6.3/WG2
XTAL2
P6.4/WG3#
NOTE: The shaded signals are not available in the 64-pin package.
B-2
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SIGNAL DESCRIPTIONS
V
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
32
1
P5.6 / READY
SS
P5.0 / ALE / ADV#
2
P5.4 / ONCE#
EXTINT
V
3
PP
V
P5.3 / RD#
P5.5 / BHE# / WRH#
P5.2 / WR# / WRL#
4
SS
5
XTAL1
6
XTAL2
P5.7 / BUSWIDTH
7
P6.6 / PWM0
AD14 / P4.6 / PBUS.14
AD13 / P4.5 / PBUS.13
AD15 / P4.7 / PBUS.15
8
P6.7 / PWM1
9
P2.6 / COMP2 / CPVER
P2.5 / COMP1 / PACT#
P2.4 / COMP0 / AINC#
P2.3 / EPA3
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
V
CC
AD12 / P4.4 / PBUS.12
AD11 / P4.3 / PBUS.11
AD10 / P4.2 / PBUS.10
AD9 / P4.1 / PBUS.9
AD8 / P4.0 / PBUS.8
AD7 / P3.7 / PBUS.7
AD6 / P3.6 / PBUS.6
AD5 / P3.5 / PBUS.5
AD4 / P3.4 / PBUS.4
AD3 / P3.3 / PBUS.3
AD2 / P3.2 / PBUS.2
AD1 / P3.1 / PBUS.1
AD0 / P3.0 / PBUS.0
RESET#
P2.2 / EPA2 / PROG#
P2.1 / EPA1 / PALE#
P2.0 / EPA0 / PVER
P0.0 / ACH0
U8XC196MC
P0.1 / ACH1
P0.2 / ACH2
View of component as
mounted on PC board
P0.3 / ACH3
P0.4 / ACH4 / PMODE.0
P0.5 / ACH5 / PMODE.1
V
REF
ANGND
P0.6 / ACH6 / PMODE.2
P0.7 / ACH7 / PMODE.3
P1.0 / ACH8
NMI
EA#
P1.1 / ACH9
V
P1.2 / ACH10 / T1CLK
P1.3 / ACH11 / T1DIR
P6.0 / WG1#
SS
V
CC
P6.5 / WG3
P6.4 / WG3#
P6.3 / WG2
P6.1 / WG1
P6.2 / WG2#
A3103-02
Figure B-1. 8XC196MC 64-lead Shrink DIP (SDIP) Package
B-3
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AD15 / P4.7 / PBUS.15
AD14 / P4.6 / PBUS.14
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
P2.5 / COMP1 / PACT#
P2.4 / COMP0 / AINC#
NC
V
CC
AD13 / P4.5 / PBUS.13
CLKOUT
NC
P2.7 / COMP3
P2.3 / EPA3
P2.2 / EPA2 / PROG#
NC
AD12 / P4.4 / PBUS.12
AD11 / P4.3 / PBUS.11
AD10 / P4.2 / PBUS.10
AD9 / P4.1 / PBUS.9
AD8 / P4.0 / PBUS.8
NC
NC
x8XC196MC
P2.1 / EPA1 / PALE#
P2.0 / EPA0 / PVER
NC
P0.0 / ACH0
P0.1 / ACH1
NC
View of component as
mounted on PC board
AD7 / P3.7 / PBUS.7
AD6 / P3.6 / PBUS.6
AD5 / P3.5. / PBUS.5
AD4 / P3.4 / PBUS.4
AD3 / P3.3 / PBUS.3
AD2 / P3.2 / PBUS.2
AD1 / P3.1 / PBUS.1
AD0 / P3.0 / PBUS.0
NC
P0.2 / ACH2
P0.3 / ACH3
P0.4 / ACH4 / PMODE.0
P0.5 / ACH5 / PMODE.1
V
REF
ANGND
P0.6 / ACH6 / PMODE.2
A3101-02
Figure B-2. 8XC196MC 84-lead PLCC Package
B-4
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SIGNAL DESCRIPTIONS
P5.2 / WR# / WRL#
P5.7 / BUSWIDTH
1
2
3
4
5
6
7
8
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
P6.7 / PWM1
P2.6 / COMP2 / CPVER
P2.5 / COMP1 / PACT#
P2.4 / COMP0 / AINC#
NC
AD15 / P4.7 / PBUS.15
AD14 / P4.6 / PBUS.14
V
CC
AD13 / P4.5 / PBUS.13
CLKOUT
NC
P2.7 / COMP3
P2.3 / EPA3
P2.2 / EPA2 / PROG#
NC
AD12 / P4.4 / PBUS.12
AD11 / P4.3 / PBUS.11
AD10 / P4.2 / PBUS.10
AD9 / P4.1 / PBUS.9
AD8 / P4.0 / PBUS.8
AD7 / P3.7 / PBUS.7
AD6 / P3.6 / PBUS.6
AD5 / P3.5 / PBUS.5
AD4 / P3.4 / PBUS.4
AD3 / P3.3 / PBUS.3
AD2 / P3.2 / PBUS.2
AD1 / P3.1 / PBUS.1
AD0 / P3.0 / PBUS.0
NC
x8XC196MC
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
NC
P2.1 / EPA1 / PALE#
P2.0 / EPA0 / PVER
NC
P0.0 / ACH0
P0.1 / ACH1
View of component as
mounted on PC board
P0.2 / ACH2
P0.3 / ACH3
P0.4 / ACH4 / PMODE.0
P0.5 / ACH5 / PMODE.1
V
REF
RESET#
ANGND
P0.6 / ACH6 / PMODE.2
P0.7 / ACH7 / PMODE.3
NMI
EA#
A3104-01
Figure B-3. 8XC196MC 80-lead Shrink EIAJ/QFP Package
B-5
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8XC196MC, MD, MH USER’S MANUAL
Table B-3. 8XC196MD Signals Arranged by Functional Categories
Address & Data
AD15:0
Programming Control
AINC#
Input/Output
P0.7:0/ACH7:0
P1.1:0/ACH9:8
P1.2/ACH10/T1CLK
P1.3/ACH11/T1DIR
P1.5:4/ACH13:12
P1.7:6
Input/Output (Cont’d)
P7.1:0/EPA5:4
P7.3:2/COMP5:4
P7.6:4
CPVER
Bus Control & Status
ALE/ADV#
BHE#/WRH#
BUSWIDTH
INST
PACT#
PALE#
P7.7/FREQOUT
PBUS.15:0
PMODE.3:0
PROG#
P2.3:0/EPA3:0
P2.7:4/COMP3:0
P3.7:0
READY
PVER
RD#
WR#/WRL#
Processor Control
CLKOUT
EA#
P4.7:0
P5.7:0
Power & Ground
P6.0/WG1#
ANGND
VCC
EXTINT
NMI
P6.1/WG1
P6.2/WG2#
VPP
ONCE#
P6.3/WG2
VREF
VSS
RESET#
XTAL1
P6.4/WG3#
P6.5/WG3
XTAL2
P6.7:6/PWM1:0
B-6
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SIGNAL DESCRIPTIONS
AD15 / P4.7 / PBUS.15
AD14 / P4.6 / PBUS.14
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
P2.5 / COMP1 / PACT#
P2.4 / COMP0 / AINC#
P7.3 / COMP5
P7.2 / COMP4
P2.7 / COMP3
P2.3 / EPA3
P2.2 / EPA2 / PROG#
P7.1 / EPA5
V
CC
AD13 / P4.5 / PBUS.13
CLKOUT
AD12 / P4.4 / PBUS.12
AD11 / P4.3 / PBUS.11
AD10 / P4.2 / PBUS.10
AD9 / P4.1 / PBUS.9
AD8 / P4.0 / PBUS.8
NC
P7.0 / EPA4
x8XC196MD
P2.1 / EPA1 / PALE#
P2.0 / EPA0 / PVER
P7.7 / FREQOUT
P0.0 / ACH0
P0.1 / ACH1
P0.2 / ACH2
NC
View of component as
mounted on PC board
AD7 / P3.7 / PBUS.7
AD6 / P3.6 / PBUS.6
AD5 / P3.5. / PBUS.5
AD4 / P3.4 / PBUS.4
AD3 / P3.3 / PBUS.3
AD2 / P3.2 / PBUS.2
AD1 / P3.1 / PBUS.1
AD0 / P3.0 / PBUS.0
P1.7
P0.3 / ACH3
P0.4 / ACH4 / PMODE.0
P0.5 / ACH5 / PMODE.1
V
REF
ANGND
P0.6 / ACH6 / PMODE.2
A3102-02
Figure B-4. 8XC196MD 84-lead PLCC Package
B-7
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8XC196MC, MD, MH USER’S MANUAL
P5.2 / WR# / WRL#
P5.7 / BUSWIDTH
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P6.7 / PWM1
P2.6 / COMP2 / CPVER
P2.5 / COMP1 / PACT#
P2.4 / COMP0 / AINC#
P7.3 / COMP5
P7.2 / COMP4
P2.7 / COMP3
P2.3 / EPA3
P2.2 / EPA2 / PROG#
P7.1 / EPA5
AD15 / P4.7 / PBUS.15
AD14 / P4.6 / PBUS.14
V
CC
AD13 / P4.5 / PBUS.13
CLKOUT
AD12 / P4.4 / PBUS.12
AD11 / P4.3 / PBUS.11
AD10 / P4.2 / PBUS.10
AD9 / P4.1 / PBUS.9
AD8 / P4.0 / PBUS.8
AD7 / P3.7 / PBUS.7
AD6 / P3.6 / PBUS.6
AD5 / P3.5 / PBUS.5
AD4 / P3.4 / PBUS.4
AD3 / P3.3 / PBUS.3
AD2 / P3.2 / PBUS.2
AD1 / P3.1 / PBUS.1
AD0 / P3.0 / PBUS.0
P1.7
x8XC196MD
9
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P7.0 / EPA4
P2.1 / EPA1 / PALE#
P2.0 / EPA0 / PVER
P7.7 / FREQOUT
P0.0 / ACH0
P0.1 / ACH1
P0.2 / ACH2
View of component as
mounted on PC board
P0.3 / ACH3
P0.4 / ACH4 / PMODE.0
P0.5 / ACH5 / PMODE.1
V
REF
RESET#
ANGND
P0.6 / ACH6 / PMODE.2
P0.7 / ACH7 / PMODE.3
NMI
EA#
A3105-01
Figure B-5. 8XC196MD 80-lead Shrink EIAJ/QFP Package
B-8
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SIGNAL DESCRIPTIONS
Table B-4. 8XC196MH Signals Arranged by Functional Categories
Address & Data
AD15:0
Programming Control
AINC#
Input/Output
P0.5:0/ACH5:0
P0.6/ACH6/T1CLK
P0.7/ACH7/T1DIR
P1.0/TXD0
Input/Output (Cont’d)
P5.0
CPVER
P5.1
Bus Control & Status
ALE/ADV#
BHE#/WRH#
BUSWIDTH
INST
PACT#
P5.7:2
PALE#
P6.0/WG1#
P6.1/WG1
P6.2/WG2#
P6.3/WG2
P6.4/WG3#
P6.5/WG3
P6.6/PWM0
P6.7/PWM1
PBUS.15:0
PMODE.3:0
PROG#
P1.1/RXD0
P1.2/TXD1
P1.3/RXD1
READY
PVER
P2.0/EPA0
RD#
P2.1/SCLK0#/BCLK0
P2.2/EPA1
WR#/WRL#
Processor Control
EA#
P2.3/COMP3
P2.4/COMP0
P2.5/COMP1
P2.6/COMP2
P2.7/SCLK1#/BCLK1
P3.7:0
Power & Ground
EXTINT
NMI
ANGND
VCC
ONCE#
VPP
RESET#
XTAL1
VREF
VSS
XTAL2
P4.7:0
NOTE: The shaded signals are not available in the 64-pin package.
B-9
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8XC196MC, MD, MH USER’S MANUAL
V
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45
44
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42
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40
39
38
37
36
35
34
32
1
P5.6 / READY
P5.4 / ONCE#
EXTINT
SS
P5.0 / ALE / ADV#
2
V
3
PP
V
P5.3 / RD#
P5.5 / BHE# / WRH#
P5.2 / WR# / WRL#
4
SS
5
XTAL1
6
XTAL2
P5.7 / BUSWIDTH
7
P6.6 / PWM0
AD14 / P4.6 / PBUS.14
AD13 / P4.5 / PBUS.13
AD15 / P4.7 / PBUS.15
8
P2.7 / SCLK1# / BCLK1
P2.6 / COMP2 / CPVER
P2.5 / COMP1 / PACT#
P2.4 / COMP0 / AINC#
P2.3 / COMP3
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
V
CC
AD12 / P4.4 / PBUS.12
AD11 / P4.3 / PBUS.11
AD10 / P4.2 / PBUS.10
AD9 / P4.1 / PBUS.9
AD8 / P4.0 / PBUS.8
AD7 / P3.7 / PBUS.7
AD6 / P3.6 / PBUS.6
AD5 / P3.5 / PBUS.5
AD4 / P3.4 / PBUS.4
AD3 / P3.3 / PBUS.3
AD2 / P3.2 / PBUS.2
AD1 / P3.1 / PBUS.1
AD0 / P3.0 / PBUS.0
RESET#
P2.2 / EPA1 / PROG#
P2.1 / SCLK0# / BCLK0 / PALE#
P2.0 / EPA0 / PVER
P0.0 / ACH0
x8XC196MH
P0.1 / ACH1
P0.2 / ACH2
View of component as
mounted on PC board
P0.3 / ACH3
P0.4 / ACH4 / PMODE.0
P0.5 / ACH5 / PMODE.1
V
REF
ANGND
P0.6 / ACH6 / T1CLK / PMODE.2
P0.7 / ACH7 / T1DIR / PMODE.3
P1.0 / TXD0
NMI
EA#
P1.1 / RXD0
V
P1.2 / TXD1
SS
V
P1.3 / RXD1
CC
P6.5 / WG3
P6.4 / WG3#
P6.3 / WG2
P6.0 / WG1#
P6.1 / WG1
P6.2 / WG2#
A2572-02
Figure B-6. 8XC196MH 64-lead Shrink DIP (SDIP) Package
B-10
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SIGNAL DESCRIPTIONS
AD15 / P4.7 / PBUS.15
AD14 / P4.6 / PBUS.14
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
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73
72
71
70
69
68
67
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65
64
63
62
61
60
59
58
57
56
55
54
P2.5 / COMP1 / PACT#
P2.4 / COMP0 / AINC#
NC
V
CC
AD13 / P4.5 / PBUS.13
NC
NC
P2.7 / SCLK1# / BCLK1
P2.3 / COMP3
P2.2 / EPA1 / PROG#
NC
AD12 / P4.4 / PBUS.12
AD11 / P4.3 / PBUS.11
AD10 / P4.2 / PBUS.10
AD9 / P4.1 / PBUS.9
AD8 / P4.0 / PBUS.8
NC
NC
x8XC196MH
P2.1 / SCLK0# / BCLK0 / PALE#
P2.0 / EPA0 / PVER
NC
P0.0 / ACH0
P0.1 / ACH1
NC
View of component as
mounted on PC board
AD7 / P3.7 / PBUS.7
AD6 / P3.6 / PBUS.6
AD5 / P3.5 / PBUS.5
AD4 / P3.4 / PBUS.4
AD3 / P3.3 / PBUS.3
AD2 / P3.2 / PBUS.2
AD1 / P3.1 / PBUS.1
AD0 / P3.0 / PBUS.0
NC
P0.2 / ACH2
P0.3 / ACH3
P0.4 / ACH4 / PMODE.0
P0.5 / ACH5 / PMODE.1
V
REF
ANGND
P0.6 / ACH6 / T1CLK / PMODE.2
A2573-03
Figure B-7. 8XC196MH 84-lead PLCC Package
B-11
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8XC196MC, MD, MH USER’S MANUAL
P5.2 / WR# / WRL#
P5.7 / BUSWIDTH
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2
3
4
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6
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P6.7 / PWM1
P2.6 / COMP2 / CPVER
P2.5 / COMP1 / PACT#
P2.4 / COMP0 / AINC#
NC
P4.7 / AD15 / PBUS.15
P4.6 / AD14 / PBUS.14
V
CC
P4.5 / AD13 / PBUS.13
NC
NC
P2.7 / SCLK1# / BCLK1
P2.3 / COMP3
P2.2 / EPA1 / PROG#
NC
P4.4 / AD12 / PBUS.12
P4.3 / AD11 / PBUS.11
P4.2 / AD10 / PBUS.10
P4.1 / AD9 / PBUS.9
P4.0 / AD8 / PBUS.8
P3.7 / AD7 / PBUS.7
P3.6 / AD6 / PBUS.6
P3.5 / AD5 / PBUS.5
P3.4 / AD4 / PBUS.4
P3.3 / AD3 / PBUS.3
P3.2 / AD2 / PBUS.2
P3.1 / AD1 / PBUS.1
P3.0 / AD0 / PBUS.0
NC
x8XC196MH
9
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NC
P2.1 / SCLK0# / BCLK0 / PALE#
P2.0 / EPA0 / PVER
NC
P0.0 / ACH0
P0.1 / ACH1
View of component as
mounted on PC board
P0.2 / ACH2
P0.3 / ACH3
P0.4 / ACH4 / PMODE.0
P0.5 / ACH5 / PMODE.1
V
REF
RESET#
ANGND
NMI
EA#
P0.6 / ACH6 / T1CLK / PMODE.2
P0.7 / ACH7 / T1DIR / PMODE.3
A2574-02
Figure B-8. 8XC196MH 80-lead Shrink EIAJ/QFP Package
B.3 SIGNAL DESCRIPTIONS
Table B-5 defines the columns used in Table B-6, which describes the signals.
B-12
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SIGNAL DESCRIPTIONS
Table B-5. Description of Columns of Table B-6
Column Heading
Name
Description
Lists the signals, arranged alphabetically. Many pins have two functions, so
there are more entries in this column than there are pins. Every signal is
listed in this column.
Type
Identifies the pin function listed in the Name column as an input (I), output
(O), bidirectional (I/O), power (PWR), or ground (GND).
Note that all inputs except RESET# are sampled inputs. RESET# is a level-
sensitive input. During powerdown mode, the powerdown circuitry uses
EXTINT as a level-sensitive input.
Description
Briefly describes the function of the pin for the specific signal listed in the
Name column. Also lists any alternate fuctions that are multiplexed with the
signal.
Table B-6. Signal Descriptions
Description
Name
Type
ACH12:0 (MC)
ACH13:0 (MD)
ACH7:0 (MH)
I
Analog Channels
These pins are analog inputs to the A/D converter.
These pins may individually be used as analog inputs (ACHx) or digital inputs
(P0.y). While it is possible for the pins to function simultaneously as analog and
digital inputs, this is not recommended because reading port 0 while a
conversion is in process can produce unreliable conversion results.
The ANGND and VREF pins must be connected for the A/D converter and port 0
to function.
ACH7:0 are multiplexed as follows: ACH0/P0.0, ACH1/P0.1, ACH2/P0.2,
ACH3/P0.3, ACH4/P0.4/PMODE.0, ACH5/P0.5/PMODE.1,
ACH6/P0.6/PMODE.2, ACH7/P0.7/PMODE.3, ACH8/P1.0, ACH9/P1.1,
ACH10/P1.2/T1CLK, ACH11/P1.3/T1DIR, and ACH12/P1.4, and ACH13/P1.5.
ACH13 is not implemented on the 8XC196MC and ACH13:8 are not
implemented on the 8XC196MH.
AD15:0
I/O
Address/Data Lines
These pins provide a multiplexed address and data bus. During the address
phase of the bus cycle, address bits 0–15 are presented on the bus and can be
latched using ALE or ADV#. During the data phase, 8- or 16-bit data is trans-
ferred.
AD7:0 are multiplexed with P3.7:0, and PBUS.7:0. AD15:8 are multiplexed with
P4.7:0 and PBUS.15:8.
ADV#
O
Address Valid
This active-low output signal is asserted only during external memory
accesses. ADV# indicates that valid address information is available on the
system address/data bus. The signal remains low while a valid bus cycle is in
progress and is returned high as soon as the bus cycle completes.
An external latch can use this signal to demultiplex the address from the
address/data bus. A decoder can also use this signal to generate chip selects
for external memory.
ADV# is multiplexed with P5.0 and ALE.
B-13
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Table B-6. Signal Descriptions (Continued)
Description
Name
AINC#
Type
I
Auto Increment
During slave programming, this active-low input enables the auto-increment
feature. (Auto increment allows reading or writing of sequential OTPROM
locations, without requiring address transactions across the PBUS for each
read or write.) AINC# is sampled after each location is programmed or dumped.
If AINC# is asserted, the address is incremented and the next data word is
programmed or dumped.
AINC# is multiplexed with P2.4 and COMP0.
Address Latch Enable
ALE
O
This active-high output signal is asserted only during external memory cycles.
ALE signals the start of an external bus cycle and indicates that valid address
information is available on the system address/data bus. ALE differs from ADV#
in that it does not remain active during the entire bus cycle.
An external latch can use this signal to demultiplex the address from the
address/data bus.
ALE is multiplexed with P5.0 and ADV#.
Analog Ground
ANGND
GND
ANGND must be connected for A/D converter and port 0 operation (also Port 1
on the 8XC196MC and MD). ANGND and VSS should be nominally at the same
potential.
BCLK1:0
(MH only)
I
Baud Clock 0 and 1
BCLK0 and 1 are alternate clock sources for the baud-rate generator input. The
maximum input frequency is FXTAL1/4.
BCLK0 is multiplexed with P2.1, SCLK0#, and PALE#. BCLK1 is multiplexed
with P2.7 and SCLK1#.
BHE#
O
Byte High Enable†
During 16-bit bus cycles, this active-low output signal is asserted for word and
high-byte reads and writes to external memory. BHE# indicates that valid data
is being transferred over the upper half of the system data bus. Use BHE#, in
conjunction with AD0, to determine which memory byte is being transferred
over the system bus:
BHE#
AD0 Byte(s) Accessed
0
0
1
0
1
0
both bytes
high byte only
low byte only
BHE# is multiplexed with P5.5 and WRH#.
†
The chip configuration register 0 (CCR0) determines whether this pin
functions as BHE# or WRH#. CCR0.2 = 1 selects BHE#; CCR0.2 = 0 selects
WRH#.
B-14
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SIGNAL DESCRIPTIONS
Table B-6. Signal Descriptions (Continued)
Name
Type
Description
BUSWIDTH
I
Bus Width
Two chip configuration register bits, CCR0.1 and CCR1.2, along with the
BUSWIDTH pin, control the data bus width. When both CCR bits are set, the
BUSWIDTH signal selects the external data bus width. When only one CCR bit
is set, the bus width is fixed at either 16 or 8 bits, and the BUSWIDTH signal
has no effect.
CCR0.1 CCR1.2 BUSWIDTH
0
1
1
1
1
0
1
1
X
X
high
low
fixed 8-bit data bus
fixed 16-bit data bus
16-bit data bus
8-bit data bus
BUSWIDTH is multiplexed with P5.7.
Clock Output
CLKOUT
(MC, MD)
O
O
Output of the internal clock generator. The CLKOUT frequency is ½ the
oscillator input frequency (FXTAL1). CLKOUT has a 50% duty cycle.
CLKOUT is not implemented on the 8XC196MH.
Event Processor Array (EPA) Compare Pins
COMP3:0(MC,
MH)
These signals are the output of the EPA compare-only channels. These pins
are multiplexed with other signals and may be configured as standard I/O.
COMP5:0
(MD)
COMP5:0 are multiplexed as follows: COMP0/P2.4/AINC#,
COMP1/P2.5/PACT#, COMP2/P2.6/CPVER, COMP3/P2.7(MC, MD),
COMP3/P2.3 (MH), COMP4/P7.2, and COMP5/P7.3.
COMP4 and COMP5 are not implemented on the 8XC196MC and MH.
Cumulative Program Verification
CPVER
EA#
O
During slave programming, a high signal indicates that all locations
programmed correctly, while a low signal indicates that an error occurred during
one of the programming operations.
CPVER is multiplexed with P2.6 and COMP2.
External Access
I
This input determines whether memory accesses to special-purpose and
program memory partitions are directed to internal or external memory. (See
Table 4-1 on page 4-2 for address ranges of special-purpose and program
memory partitions.) These accesses are directed to internal memory if EA# is
held high and to external memory if EA# is held low. For an access to any other
memory location, the value of EA# is irrelevant.
EA# also controls entry into the programming modes. If EA# is at VPP voltage
(typically +12.5 V) on the rising edge of RESET#, the microcontroller enters a
programming mode.
NOTE: Systems with EA# tied inactive have idle time between external bus
cycles. When the address/data bus is idle, you can use ports 3 and 4
for I/O. Systems with EA# tied active cannot use ports 3 and 4 as
standard I/O; when EA# is active, these ports will function only as the
address/data bus.
EA# is sampled and latched only on the rising edge of RESET#. Changing the
level of EA# after reset has no effect.
Always connect EA# to VSS when using a microcontroller that has no internal
nonvolatile memory.
B-15
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8XC196MC, MD, MH USER’S MANUAL
Table B-6. Signal Descriptions (Continued)
Name
Type
Description
EPA3:0 (MC)
EPA5:0 (MD)
EPA1:0 (MH)
I/O
Event Processor Array (EPA) Capture/Compare Channels
High-speed input/output signals for the EPA capture/compare channels.
EPA5:0 are multiplexed as follows: EPA0/P2.0/PVER, EPA1/P2.1/PALE# (MC,
MD), EPA1/P2.2/PROG# (MH), EPA2/P2.2/PROG#, EPA3/P2.3, EPA4/P7.0,
and EPA5/P7.1.
EPA5:4 are not implemented on the 8XC196MC and EPA5:2 are not
implemented on the 8XC196MH.
EXTINT
I
External Interrupt
This programmable interrupt is controlled by the WG_PROTECT register. This
register controls whether the interrupt is edge triggered or sampled and whether
a rising edge/high level or falling edge/low level activates the interrupt.
In powerdown mode, asserting the EXTINT signal for at least 50 ns causes the
device to resume normal operation. The interrupt need not be enabled. If the
EXTINT interrupt is enabled, the CPU executes the interrupt service routine.
Otherwise, the CPU executes the instruction that immediately follows the
command that invoked the power-saving mode.
In idle mode, asserting any enabled interrupt causes the device to resume
normal operation.
FREQOUT
(MD only)
O
O
Frequency Generator Output
A fixed 50% duty cycle waveform that can vary in frequency from 4 KHz to 1
MHz (assuming FXTAL1 = 16 MHz).
FREQOUT is multiplexed with P7.7.
FREQOUT is not implemented on the 8XC196MC or MH.
Instruction Fetch
INST
This active-high output signal is valid only during external memory bus cycles.
When high, INST indicates that an instruction is being fetched from external
memory. The signal remains high during the entire bus cycle of an external
instruction fetch. INST is low for data accesses, including interrupt vector
fetches and chip configuration byte reads. INST is low during internal memory
fetches.
INST is multiplexed with P5.1.
Nonmaskable Interrupt
NMI
I
In normal operating mode, a rising edge on NMI generates a nonmaskable
interrupt. NMI has the highest priority of all prioritized interrupts. Assert NMI for
greater than one state time to guarantee that it is recognized.
B-16
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SIGNAL DESCRIPTIONS
Table B-6. Signal Descriptions (Continued)
Name
ONCE#
Type
Description
I
On-circuit Emulation
Holding ONCE# low during the rising edge of RESET# places the device into
on-circuit emulation (ONCE) mode. This mode puts all pins, except XTAL1 and
XTAL2, into a high-impedance state, thereby isolating the device from other
components in the system. The value of ONCE# is latched when the RESET#
pin goes inactive. While the device is in ONCE mode, you can debug the
system using a clip-on emulator.
To exit ONCE mode, reset the device by pulling the RESET# signal low. To
prevent inadvertent entry into ONCE mode, either configure this pin as an
output or hold it high during reset and ensure that your system meets the VIH
specification (see datasheet).
ONCE# is multiplexed with P5.4.
P0.7:0
I
Port 0
This is a high-impedance, input-only port. Port 0 pins should not be left floating.
These pins may individually be used as analog inputs (ACHx) or digital inputs
(P0.y). While it is possible for the pins to function simultaneously as analog and
digital inputs, this is not recommended because reading port 0 while a
conversion is in process can produce unreliable conversion results.
ANGND and VREF must be connected for port 0 to function.
Port 0 is multiplexed as follows: P0.0/ACH0, P0.1/ACH1, P0.2/ACH2,
P0.3/ACH3, P0.4/ACH4/PMODE.0, P0.5/ACH5/PMODE.1,
P0.6/ACH6/PMODE.2 (MC, MD), P0.6/ACH6/T1CLK/PMODE.2 (MH),
P0.7/ACH7/PMODE.3 (MC, MD), and P0.7/ACH7/T1DIR/PMODE.3 (MH).
P1.4:0 (MC)
P1.7:0 (MD)
I
Port 1
This is a high-impedance, input-only port.
On the 8XC196MC and MD, some port 1 pins may individually be used as
analog inputs (ACHx) or digital inputs (P1.y). While it is possible for the pins to
function simultaneously as analog and digital inputs, this is not recommended
because reading port 1 while a conversion is in process can produce unreliable
conversion results.
ANGND and VREF must be connected for port 1 to function.
Port 1 is multiplexed as follows: P1.0/ ACH8, P1.1/ACH9, P1.2/ACH10/T1CLK,
P1.3/ACH11/T1DIR, P1.4/ACH12, and P1.5/ACH13).
P1.6 and P1.7 are not multiplexed with any other signals. P1.7:5 are not
implemented on the 8XC196MC.
P1.3:0 (MH)
I/O
Port 1
This is a standard, bidirectional port that is multiplexed with individually
selectable special-function signals.
On the 8XC196MH, port 1 is multiplexed as follows: P1.0/ TXD0, P1.1/RXD0,
P1.2/TXD1, and P1.3/RXD1.
B-17
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8XC196MC, MD, MH USER’S MANUAL
Table B-6. Signal Descriptions (Continued)
Description
Name
P2.7:0
Type
I/O
Port 2
This is a standard, 8-bit, bidirectional port that is multiplexed with individually
selectable special-function signals.
P2.6 is multiplexed with a special test-mode-entry function. If this pin is held low
during reset, the device will enter a reserved test mode, so exercise caution if
you use this pin for input. If you choose to configure this pin as an input, always
hold it high during reset and ensure that your system meets the VIH specification
(see datasheet) to prevent inadvertent entry into ONCE mode.
On the 8XC196MC and MD, port 2 is multiplexed as follows: P2.0/EPA0/PVER,
P2.1/EPA1/PALE#, P2.2/EPA2/PROG#, P2.3/EPA3, P2.4/COMP0/AINC#,
P2.5/COMP1/PACT#, P2.6/COMP2/CPVER, and P2.7/COMP3.
On the 8XC196MH, port 2 is multiplexed as follows: P2.0/EPA0/PVER,
P2.1/SCLK0#/BCLK0/PALE#, P2.2/EPA1/PROG#, P2.3/COMP3,
P2.4/COMP0/AINC#, P2.5/COMP1/PACT#, P2.6/COMP2/CPVER, and
P2.7/SCLK1#/BCLK1.
P3.7:0
P4.7:0
P5.7:0
I/O
I/O
I/O
Port 3
This is a memory-mapped, 8-bit, bidirectional port with programmable open-
drain or complementary output modes. The pins are shared with the
multiplexed address/data bus, which has complementary drivers.
P3.7:0 are multiplexed with AD7:0 and PBUS.7:0.
Port 4
This is a memory-mapped, 8-bit, bidirectional port with programmable open-
drain or complementary output modes. The pins are shared with the
multiplexed address/data bus, which has complementary drivers.
P4.7:0 are multiplexed with AD15:8 and PBUS15:8.
Port 5
This is a memory-mapped, 8-bit, bidirectional port that is multiplexed with
individually selectable control signals.
P5.4 is multiplexed with the ONCE# function. If this pin is held low during reset,
the device will enter ONCE mode , so exercise caution if you use this pin for
input. If you choose to configure this pin as an input, always hold it high during
reset and ensure that your system meets the VIH specification (see datasheet)
to prevent inadvertent entry into ONCE mode.
Port 5 is multiplexed as follows: P5.0/ALE/ADV#, P5.1/INST, P5.2/WR#/WRL#,
P5.3/RD#, P5.4/ONCE#, P5.5/BHE#/WRH#, P5.6/READY, and
P5.7/BUSWIDTH.
P6.7:0
O
Port 6
This is a standard, 8-bit, output-only port that is multiplexed with the special
functions of the waveform generator and PWM peripherals. The WG_OUT
register configures the pins, establishes the output polarity, and controls
whether changes to the outputs are synchronized with an event or take effect
immediately.
Port 6 is multiplexed as follows: P6.0/WG1#, P6.1/WG1, P6.2/WG2#,
P6.3/WG2, P6.4/WG3#, P6.5/WG3, P6.6/PWM0, and P6.7/PWM1.
B-18
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SIGNAL DESCRIPTIONS
Table B-6. Signal Descriptions (Continued)
Name
P7.7:0
Type
Description
I/O
Port 7
(MD only)
This is a standard, 8-bit, bidirectional port with Schmitt-trigger inputs.
Port 7 is multiplexed as follows: P7.0/EPA4, P7.1/EPA5, P7.2/COMP4,
P7.3/COMP5, and P7.7/FREQOUT. P7.6:4 are not multiplexed.
Port 7 is not implemented on the 8XC196MC and 8XC196MH.
Programming Active
PACT#
O
During auto programming or ROM-dump, a low signal indicates that
programming or dumping is in progress, while a high signal indicates that the
operation is complete.
PACT# is multiplexed with P2.5 and COMP1.
Programming ALE
PALE#
I
During slave programming, a falling edge causes the device to read a
command and address from the PBUS.
PALE# is multiplexed with P2.1 and EPA1 (MC, MD) and P2.1, SCLK0#, and
BCLK0 (MH).
PBUS.15:0
I/O
Address/Command/Data Bus
During slave programming, ports 3 and 4 serve as a bidirectional port with
open-drain outputs to pass commands, addresses, and data to or from the
device. Slave programming requires external pull-up resistors.
During auto programming and ROM-dump, ports 3 and 4 serve as a regular
system bus to access external memory. P4.6 and P4.7 are left unconnected;
P1.1 and P1.2 serve as the upper address lines.
Slave programming:
PBUS.7:0 are multiplexed with AD7:0 and P3.7:0.
PBUS.15:8 are multiplexed with AD15:8 and P4.7:0.
Auto programming:
On the 8XC196MC, MC, and MH, PBUS.7:0 are multiplexed with AD7:0 and
P3.7:0.
On the 8XC196MC and MD, PBUS.13:8 are multiplexed with AD13:8 and
P4.5:0; PBUS15:14 are multiplexed with P1.2:1.
On the 8XC196MH, PBUS.11:8 are multiplexed with AD11:8 and P4.3:0;
PBUS15:12 are multiplexed with P1.3:0.
PMODE.3:0
I
Programming Mode Select
Determines the programming mode. PMODE is sampled after a device reset
and must be static while the microcontroller is operating. (Table 16-7 on page
16-13 lists the PMODE values and programming modes.)
PMODE.3:0 are multiplexed with P0.7:4 and ACH7:4. On the 8XC196MH,
PMODE.2 is also is also multiplexed with T1CLK, and PMODE.3 is also
multiplexed with T1DIR.
B-19
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8XC196MC, MD, MH USER’S MANUAL
Table B-6. Signal Descriptions (Continued)
Description
Name
PROG#
Type
I
Programming Start
During programming, a falling edge latches data on the PBUS and begins
programming, while a rising edge ends programming. The current location is
programmed with the same data as long as PROG# remains asserted, so the
data on the PBUS must remain stable while PROG# is active.
During a word dump, a falling edge causes the contents of an OTPROM
location to be output on the PBUS, while a rising edge ends the data transfer.
On the 8XC196MC and MD, PROG# is multiplexed with P2.2 and EPA2. On the
8XC196MH, PROG# is multiplexed with P2.2 and EPA1.
O
Program Verification
PVER
During slave or auto programming, PVER is updated after each programming
pulse. A high output signal indicates successful programming of a location,
while a low signal indicates a detected error.
PVER is multiplexed with P2.0 and EPA0.
Pulse Width Modulator Outputs
PWM1:0
RD#
O
O
These are PWM output pins with high-current drive capability.
PWM1:0 are multiplexed with P6.7:6.
Read
Read-signal output to external memory. RD# is asserted only during external
memory reads.
RD# is multiplexed with P5.3.
Ready Input
READY
I
This active high input along with the chip configuration registers determine the
number of wait states inserted into the bus cycle. The chip configuration
registers selects the maximum number of wait states (0, 1, 2, 3, or infinite) that
can be inserted into the bus cycle. While READY is low, wait states are inserted
into the bus cycle until the programmed number of wait states is reached. If
READY is pulled high before the programmed number of wait states is reached,
no additional wait states will be inserted into the bus cycle.
READY is multiplexed with P5.6.
RESET#
I/O
Reset
A level-sensitive reset input to and open-drain system reset output from the
microcontroller. Either a falling edge on RESET# or an internal reset turns on a
pull-down transistor connected to the RESET# pin for 16 state times. In the
powerdown and idle modes, asserting RESET# causes the chip to reset and
return to normal operating mode. The 8XC196MH provides the option of
preventing an internal reset from generating a reset on the external pin (see
“Resetting the Device” on page 13-8). After a device reset, the first instruction
fetch is from FF2080H.
RXD1:0
I/O
Receive Serial Data 0 and 1
(MH only)
In modes 1, 2, and 3, RXD0 and 1 receive serial port input data. In mode 0, they
function as either inputs or open-drain outputs for data.
RXD0 is multiplexed with P1.1 and RXD1 is multiplexed with P1.3.
B-20
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SIGNAL DESCRIPTIONS
Table B-6. Signal Descriptions (Continued)
Name
Type
Description
SCLK1:0#
(MH only)
I/O
Shift Clock 0 and 1
In SIO mode 4, SCLKx# are bidirectional shift clock signals that synchronize the
serial data transfer. The DIR bit in the SP_CON register controls the direction of
SCLKx#.
DIR = 1 allows an external shift clock to be input on SCLKx#.
DIR = 0 causes SCLKx# to output the internal shift clock.
SCLK0# is multiplexed with P2.1, BCLK0, and PALE#. SCLK1# is multiplexed
with P2.7 and BCLK1.
T1CLK
I
Timer 1 External Clock
External clock for timer 1. Timer 1 increments (or decrements) on both rising
and falling edges of T1CLK. Also used in conjunction with T1DIR for
quadrature counting mode.
and
External clock for the serial I/O baud-rate generator input (program selectable).
On the 8XC196MC and MD, T1CLK is multiplexed with P1.2 and ACH10. On
the 8XC196MH, T1CLK is multiplexed with P0.6, ACH6, and PMODE.2.
T1DIR
I
Timer 1 External Direction
External direction (up/down) for timer 1. Timer 1 increments when T1DIR is high
and decrements when it is low. Also used in conjunction with T1CLK for
quadrature counting mode.
On the 8XC196MC and MD, T1DIR is multiplexed with P1.3 and ACH11. On the
8XC196MH, T1DIR is multiplexed with P0.7, ACH7, and PMODE.3.
TXD1:0
O
Transmit Serial Data 0 and 1
(MH only)
In serial I/O modes 1, 2, and 3, TXD0 and 1 transmit serial port output data. In
mode 0, they are the serial clock outputs.
TXD0 is multiplexed with P1.0 and TXD1 is multiplexed with P1.2.
TXD0 and 1 are not implemented on the 8XC196MC and MD.
VCC
VPP
PWR Digital Supply Voltage
Connect each VCC pin to the digital supply voltage.
PWR Programming Voltage
During programming, the VPP pin is typically at +12.5 V (VPP voltage).
Exceeding the maximum VPP voltage specification can damage the device.
PP also causes the device to exit powerdown mode when it is driven low for at
V
least 50 ns. Use this method to exit powerdown only when using an external
clock source because it enables the internal phase clocks, but not the internal
oscillator. See “Driving the Vpp Pin Low” on page 14-6.
On devices with no internal nonvolatile memory, connect VPP to VCC
.
VREF
PWR Reference Voltage for the A/D Converter
This pin also supplies operating voltage to both the analog portion of the A/D
converter and the logic used to read port 0 (also port 1 in the 8XC196MC and
8XC196MD).
VSS
GND
Digital Circuit Ground
These pins supply ground for the digital circuitry. Connect each VSS pin to
ground through the lowest possible impedance path.
B-21
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8XC196MC, MD, MH USER’S MANUAL
Table B-6. Signal Descriptions (Continued)
Name
WG3:1
Type
Description
O
Waveform Generator Phase 1–3 Positive Outputs
3-phase output signals used in motion-control applications.
WG1 is multiplexed with P6.1, WG2 is multiplexed with P6.3, and WG3 is
multiplexed with P6.5.
WG3:1#
WR#
O
O
Waveform Generator Phase 1–3 Negative Outputs
Complimentary 3-phase output signals used in motion-control applications.
WG1# is multiplexed with P6.0, WG2# is multiplexed with P6.2, and WG3# is
multiplexed with P6.4.
Write†
This active-low output indicates that an external write is occurring. This signal is
asserted only during external memory writes.
WR# is multiplexed with P5.2 and WRL#.
†
The chip configuration register 0 (CCR0) determines whether this pin
functions as WR# or WRL#. CCR0.2 = 1 selects WR#; CCR0.2 = 0 selects
WRL#.
WRH#
O
Write High†
During 16-bit bus cycles, this active-low output signal is asserted for high-byte
writes and word writes to external memory. During 8-bit bus cycles, WRH# is
asserted for all write operations.
WRH# is multiplexed with P5.5 and BHE#.
†
The chip configuration register 0 (CCR0) determines whether this pin
functions as BHE# or WRH#. CCR0.2 = 1 selects BHE#; CCR0.2 = 0 selects
WRH#.
WRL#
O
Write Low†
During 16-bit bus cycles, this active-low output signal is asserted for low-byte
writes and word writes to external memory. During 8-bit bus cycles, WRL# is
asserted for all write operations.
WRL# is multiplexed with P5.2 and WR#.
†
The chip configuration register 0 (CCR0) determines whether this pin
functions as WR# or WRL#. CCR0.2 = 1 selects WR#; CCR0.2 = 0 selects
WRL#.
XTAL1
XTAL2
I
Input Crystal/Resonator or External Clock Input
Input to the on-chip oscillator and the internal clock generators. The internal
clock generators provide the peripheral clocks, CPU clock, and CLKOUT signal
(MC/MD only). When using an external clock source instead of the on-chip
oscillator, connect the clock input to XTAL1. The external clock signal must
meet the VIH specification for XTAL1 (see datasheet).
O
Inverted Output for the Crystal/Resonator
Output of the on-chip oscillator inverter. Leave XTAL2 floating when the design
uses an external clock source instead of the on-chip oscillator.
B.4 DEFAULT CONDITIONS
Table B-8 lists the values of the signals of the 8XC196MC and 8XC196MD during various oper-
ating conditions. The shaded rows indicate those signals that are available only on the
B-22
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SIGNAL DESCRIPTIONS
8XC196MD. Table B-9 lists the same information for the 8XC196MH. Table B-7 defines the
symbols used to represent the pin status. Refer to the DC Characteristics table in the datasheet for
actual specifications for VOL, V , VOH, and V .
IL
IH
Table B-7. Definition of Status Symbols
Symbol
Definition
Symbol
MD0
Definition
Medium pull-down
0
Voltage less than or equal to VOL, VIL
Voltage greater than or equal to VOH, VIH
High impedance
1
MD1
WK0
WK1
ODIO
Medium pull-up
Weak pull-down
Weak pull-up
HiZ
LoZ0
LoZ1
Low impedance; strongly driven low
Low impedance; strongly driven high
Open-drain I/O
Table B-8. 8XC196MC and MD Default Signal Conditions
Upon RESET#
Alternate
Functions
During
RESET# Active
Port Signals
Inactive
(Note 14)
Idle
Powerdown
P0.7:0
ACH7:0
HiZ
HiZ
—
—
HiZ
HiZ
HiZ
HiZ
P1.1:0
ACH9:8
ACH10/T1CLK
ACH11/T1DIR
ACH12
P1.2
HiZ
—
HiZ
HiZ
P1.3
HiZ
—
HiZ
HiZ
P1.4
HiZ
—
HiZ
HiZ
P1.5 (Note 15)
P1.7:6 (Note 15)
P2.0
ACH13
HiZ
—
HiZ
HiZ
—
HiZ
—
HiZ
HiZ
EPA0
WK1 (Note 1)
WK1
WK1
WK1
WK1
WK1
WK1
(Note 12)
(Note 12)
(Note 12)
(Note 12)
(Note 12)
(Note 12)
(Note 12)
(Note 12)
P2.1
EPA1
P2.3:2
EPA3:2
P2.6:4
COMP2:0
WK1; except
P2.5 = LZ
(Note 1)
P2.7
P3.7:0
P4.7:0
P5.0
P5.1
P5.2
P5.3
P5.4
P5.5
P5.6
P5.7
P6.0
P6.1
P6.2
COMP3
AD7:0
WK1
WK1
WK1
HiZ
(Note 12)
(Note 3)
(Note 12)
(Note 3)
AD15:8
ADV#/ALE
INST
WK1
HiZ
(Note 3)
(Note 3)
WK1 (Note 1)
WK1
WK1 (Note 4)
WK1
(Note 8)
(Note 8)
(Note 9)
(Note 9)
WR#/WRL#
RD#
WK1 (Note 1)
WK1 (Note 1)
MD1
WK1
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 11)
(Note 11)
(Note 13)
(Note 13)
(Note 13)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 11)
(Note 11)
(Note 13)
(Note 13)
(Note 13)
WK1 (Note 4)
LZ (Note 1)
WK1 (Note 4)
(Note 5)
(Note 6)
WK1
ONCE#
BHE#/WRH#
READY
BUSWIDTH
WG1#
WK1
WK1
WK1
WK1
WG1
WK1
WK1
WG2#
WK1
WK1
B-23
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8XC196MC, MD, MH USER’S MANUAL
Table B-8. 8XC196MC and MD Default Signal Conditions (Continued)
Upon RESET#
Inactive
(Note 14)
Alternate
Functions
During
RESET# Active
Port Signals
Idle
Powerdown
P6.3
WG2
WK1
WK1
WK1
WK1
WK1
—
(Note 13)
(Note 13)
(Note 13)
(Note 13)
(Note 13)
(Note 12)
(Note 12)
(Note 12)
(Note 12)
(Note 13)
(Note 13)
(Note 13)
(Note 13)
(Note 13)
(Note 12)
(Note 12)
(Note 12)
(Note 12)
LoZ0
P6.4
WG3#
P6.5
WG3
WK1
P6.6
PWM0
PWM1
EPA5:4
COMP5:4
—
WK0
P6.7
WK0
—
P7.1:0 (Note 15)
P7.3:2 (Note 15)
P7.6:4 (Note 15)
P7.7 (Note 15)
—
WK1 (Note 1)
WK1
—
—
WK1
—
FREQOUT
CLKOUT
WK1
—
CLKOUTactive,
LoZ0/1
—
CLKOUT
active, LoZ0/1
—
—
—
—
EA#
HiZ
HiZ
—
—
—
—
HiZ
HiZ
HiZ
HiZ
EXTINT
NMI
WK0
WK0
HiZ
WK0
HiZ
RESET#
LoZ0/HiZ
(Note 2)
—
—
—
VPP
HiZ
—
LoZ1
LoZ1
XTAL1
XTAL2
Osc input, HiZ
Osc input, HiZ
Osc input, HiZ Osc input, HiZ
Osc output,
LoZ0/1
Osc output,
LoZ0/1
Osc output,
LoZ0/1
(Note 7)
NOTES:
1. These pins also control test mode entry.
2. If Disable Reset Out = 0, pin is LoZ0. If Disable Reset Out =1, pin is HiZ.
3. If EA# = 0, Port 3 and Port 4 = HiZ. If EA# = 1, Port 3 and Port 4 = ODIO.
4. If EA# = 1, pin is WK1. If EA# = 0, P5.0, P5.3, and P5.5 are configured as outputs and function as
ADV#, RD#, or BHE# respectively.
5. READY function not selected and three wait states inserted to allow fetch of CCB.
6. BUSWIDTH function is selected.
7. If XTAL1 = 1, pin is LoZ0. If XTAL1 = 0, pin is LoZ1.
8. If P5_MODE.0 = 0, port is as programmed.
If P5_MODE.0 = 1 and CCR.3 = 1 (ALE mode), pin is LoZ0. If P5_MODE.0 = 1 and CCR.3 = 0 (ADV#
mode), pin is LoZ1.
9. If P5_MODE.1 = 0, port is as programmed. If P5_MODE.1 = 1, pin is LoZ0.
10. If P5_MODE.y = 0, port is as programmed. If P5_MODE.y = 1, pin is LoZ1.
11. If P5_MODE.y = 0, port is as programmed. If P5_MODE.y = 1, pin is HiZ.
12. If Px_MODE.y = 0, port is as programmed. If Px_MODE.y = 1, pin is as specified by the associated
peripheral.
13. If output port, pin is as programmed. If special function, pin is as specified by the associated periph-
eral.
14. The values in this column are valid until your software writes to Px_MODE.
15. Shaded rows indicate those signals that are available only on the 8XC196MD.
B-24
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SIGNAL DESCRIPTIONS
Table B-9. 8XC196MH Default Signal Conditions
Upon
During
RESET#
Active
Alternate
Functions
RESET#
Inactive
(Note 12)
Port Signals
Idle
Powerdown
P0.5:0
P0.6
P0.7
P1.0
P1.1
P1.2
P1.3
P2.0
P2.1
P2.2
P2.3
P2.5:4
P2.6
P2.7
P3.7:0
P4.7:0
P5.0
P5.1
P5.2
P5.3
P5.4
P5.5
P5.6
P5.7
P6.0
P6.1
P6.2
P6.3
P6.4
P6.5
P6.6
P6.7
—
ACH5:0
HiZ
HiZ
—
—
HiZ
HiZ
ACH6/T1CLK
ACH7/T1DIR
TXD0
HiZ
HiZ
HiZ
—
HiZ
HiZ
WK1
WK1
WK1
WK1
WK1
WK1
WK1
WK1
WK1
WK1
MD1
WK1
HiZ
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 3)
(Note 6)
(Note 7)
(Note 8)
(Note 8)
(Note 8)
(Note 10)
(Note 9)
(Note 9)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
HiZ
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 3)
(Note 3)
(Note 6)
(Note 7)
(Note 8)
(Note 8)
(Note 8)
(Note 10)
(Note 9)
(Note 9)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
(Note 11)
HiZ
RXD0
WK1
TXD1
WK1
RXD1
WK1
EPA0
WK1 (Note 1)
WK1
BCLK0 /SCLK0#
EPA1
WK1
COMP3
COMP1:0
COMP2
BCLK1 /SCLK1#
AD7:0
WK1
WK1
MD1 (Note 1)
WK1
WK1
AD15:8
ADV#/ALE
INST
WK1
HiZ
WK1 (Note 1)
WK1
(Note 6)
WK1
WK1
(Note 4)
MD1
(Note 5)
WK1
WK1
WK1
WK1
WK1
WK1
WK1
WK1
WK1
WK1
—
WR#/WRL#
RD#
WK1 (Note 1)
WK1 (Note 1)
MD1 (Note 1)
WK1
ONCE#
BHE#/WRH#
READY
BUSWIDTH
WG1#
WK1
WK1
WK1
WG1
WK1
WG2#
WK1
WG2
WK1
WG3#
WK1
WG3
WK1
PWM0
WK0
PWM1
WK0
EA#
HiZ
—
EXTINT
NMI
HiZ
—
HiZ
HiZ
—
WK0
—
WK0
WK0
—
RESET#
LoZ0/HiZ
(Note 2)
—
HiZ
HiZ
—
VPP
HiZ
—
LoZ1
LoZ1
B-25
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8XC196MC, MD, MH USER’S MANUAL
Table B-9. 8XC196MH Default Signal Conditions (Continued)
Upon
During
RESET#
Active
Alternate
Functions
RESET#
Inactive
(Note 12)
Port Signals
Idle
Powerdown
—
XTAL1
XTAL2
Osc input, HiZ
—
—
Osc input, HiZ Osc input, HiZ
—
Osc output,
LoZ0/1
Osc output,
LoZ0/1
(Note 5)
NOTES:
1. These pins also control test mode entry.
2. If Disable Reset Out = 0, pin is LoZ0. Else if Disable Reset Out =1, pin is HiZ.
3. If EA# = 0, Port 3 and Port 4 = HiZ. If EA# = 1, Port 3 and Port 4 = ODIO.
4. If EA# = 1, pin is WK1. If EA# = 0, P5.0, P5.3, and P5.5 are configured as outputs and function as
ADV#, RD#, or BHE# respectively.
5. If XTAL1 = 1, pin is LoZ0. If XTAL1 = 0, pin is LoZ1.
6. If P5_MODE.0 = 0, port is as programmed.
If P5_MODE.0 = 1 and CCR.3 = 1 (ALE mode), pin is LoZ0. If P5_MODE.0 = 1 and CCR.3 = 0 (ADV#
mode), pin is LoZ1.
7. If P5_MODE.1 = 0, port is as programmed. If P5_MODE.1 = 1, pin is LoZ0.
8. If P5_MODE.y = 0, port is as programmed. If P5_MODE.y = 1, pin is LoZ1.
9. If P5_MODE.y = 0, port is as programmed. If P5_MODE.y = 1, pin is HiZ.
10. If Px_MODE.y = 0, port is as programmed. If Px_MODE.y = 1, pin is as specified by the associated
peripheral.
11. If output port, pin is as programmed. If special function, pin is as specified by the associated periph-
eral.
12. The values in this column are valid until your software writes to Px_MODE.
B-26
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C
Registers
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APPENDIX C
REGISTERS
This appendix provides reference information about the device registers. Table C-1 lists the mod-
ules and major components of the device with their related configuration and status registers. Ta-
ble C-2 lists the registers, arranged alphabetically by mnemonic, along with their names,
addresses, and reset values. Following the tables, individual descriptions of the registers are ar-
ranged alphabetically by mnemonic.
Table C-1. Modules and Related Registers
EPA
A/D Converter
Chip Configuration
CPU
(8XC196MC, MH, x = 0–3)
(8XC196MD, x = 0–5)
AD_COMMAND
AD_RESULT
AD_TEST
CCR0
ONES_REG
PSW
COMPx_CON
COMPx_TIME
EPAx_CON
CCR1
GEN_CON (8XC196MH)
PPW (or SP_PPW)
USFR
SP
AD_TIME
ZERO_REG
EPAx_TIME
Frequency Generator
(8XC196MD)
I/O Ports
Interrupts and PTS
Memory Control
FREQ_CNT
FREQ_GEN
Px_DIR†
INT_MASK
INT_MASK1
INT_PEND
INT_PEND1
PI_MASK
PI_PEND
PTSSEL
WSR
Px_MODE†
Px_PIN††
Px_REG†
PTSSRV
PWM
(x = 0–1)
Serial Port
(8XC196MH, x = 0–1)
Timers
(x = 0–1)
Waveform Generator
(x = 1–3)
PWM_COUNT
SBUFx_RX
SBUFx_TX
SPx_BAUD
SPx_CON
TxCONTROL
T1RELOAD
TIMERx
WG_COMPx
PWM_PERIOD
PWMx_CONTROL
WG_CONTROL
WG_COUNTER
WG_OUTPUT
WG_PROTECT
WG_RELOAD
WATCHDOG
SPx_STATUS
†
For the 8XC196MC, x = 2, 5; for the 8XC196MD, x = 2, 5, 7; for the 8XC196MH, x = 1, 2, 5.
For the 8XC196MC and 8XC196MH, x = 0–5; for the 8XC196MD, x = 0–5, 7.
††
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Table C-2. Register Name, Address, and Reset Status
Binary Reset Value
Register
Mnemonic
Hex
Addr
Register Name
High
Low
0000
AD_COMMAND
A/D Command
1FAC
1FAA
1000
1100
1100
1100
1000
1111
AD_RESULT (MC, MD)
AD_RESULT (MH)
1111
0111
1111
1111
0000
0000
0000
1000
1111
A/D Result
A/D Test
AD_TEST (MC, MD)
AD_TEST (MH)
1FAE
AD_TIME
A/D Time
1FAF
†††
CCR0
Chip Configuration 0
Chip Configuration 1
EPA Compare 0 Control
EPA Compare 1 Control
EPA Compare 2 Control
XXXX XXXX
XXXX XXXX
CCR1
†††
COMP0_CON
COMP1_CON
COMP2_CON
1F58
1F5C
1F60
1F64
1F4C
1F68
1F6C
1F5A
1F5E
1F62
1F66
1F4E
1F6A
1F6E
1F40
1F44
1F48
1F4C
1F50
1F54
1F42
0000
0000
0000
0000
0000
0000
COMP3_CON (MC, MD)
COMP3_CON (MH)
EPA Compare 3 Control
0000
0000
COMP4_CON (MD)
COMP5_CON (MD)
COMP0_TIME
EPA Compare 4 Control
EPA Compare 5 Control
EPA Compare 0 Time
EPA Compare 1 Time
EPA Compare 2 Time
0000
0000
0000
0000
XXXX XXXX XXXX XXXX
XXXX XXXX XXXX XXXX
XXXX XXXX XXXX XXXX
COMP1_TIME
COMP2_TIME
COMP3_TIME (MC, MD)
COMP3_TIME (MH)
EPA Compare 3 Time
XXXX XXXX XXXX XXXX
COMP4_TIME (MD)
COMP5_TIME (MD)
EPA0_CON
EPA Compare 4 Time
XXXX XXXX XXXX XXXX
XXXX XXXX XXXX XXXX
EPA Compare 5 Time
EPA Capture/Comp 0 Control
EPA Capture/Comp 1 Control
EPA Capture/Comp 2 Control
EPA Capture/Comp 3 Control
EPA Capture/Comp 4 Control
EPA Capture/Comp 5 Control
EPA Capture/Comp 0 Time
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
EPA1_CON
EPA2_CON (MC, MD)
EPA3_CON (MC, MD)
EPA4_CON (MD)
EPA5_CON (MD)
EPA0_TIME
XXXX XXXX XXXX XXXX
†
Reset value is FFH when pin is not driven.
††
Reset value is 80H if the EA# pin is high, A9H if EA# is low.
††† The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after a device reset,
unless the device is entering programming modes (see “Entering Programming Modes” on page
16-13), in which case the programming chip configuration bytes (PCCBs) are used. The CCBs reside in
internal nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
C-2
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REGISTERS
Table C-2. Register Name, Address, and Reset Status (Continued)
Binary Reset Value
High Low
Register
Mnemonic
Hex
Addr
Register Name
EPA1_TIME
EPA Capture/Comp 1 Time
EPA Capture/Comp 2 Time
EPA Capture/Comp 3 Time
EPA Capture/Comp 4 Time
EPA Capture/Comp 5 Time
Frequency Gen Count
Frequency
1F46
1F4A
1F4E
1F52
1F56
1FBA
1FB8
1FA0
0008
0013
0009
0012
0002
1F9B
1FD2
1FF3
1FD3
1F99
1FD0
1FF1
1FD1
1FA8
1FDA
1FA9
1F9F
1FD6
1FFE
1FFF
1FF7
XXXX XXXX XXXX XXXX
XXXX XXXX XXXX XXXX
XXXX XXXX XXXX XXXX
XXXX XXXX XXXX XXXX
EPA2_TIME (MC, MD)
EPA3_TIME (MC, MD)
EPA4_TIME (MD)
EPA5_TIME (MD)
FREQ_CNT (MD)
FREQ_GEN (MD)
GEN_CON (MH)
INT_MASK
XXXX XXXX 0000
0000
0000
0000
0000
0000
0000
0000
0000
1111
1111
1111
1111
1111
0000
0000
0000
0000
0000
0000
0000
0000
General Configuration
Interrupt Mask
INT_MASK1
Interrupt Mask 1
INT_PEND
Interrupt Pending
Interrupt Pending 1
Ones Register
INT_PEND1
ONES_REG
1111
1111
1111
1111
1111
1111
1111
0000
0000
P1_DIR (MH)
P2_DIR
Port 1 I/O Direction
Port 2 I/O Direction
Port 5 I/O Direction
Port 7 I/O Direction
Port 1 Mode
P5_DIR
P7_DIR (MD)
P1_MODE (MH)
P2_MODE
Port 2 Mode
0000
††
P5_MODE
Port 5 Mode
P7_MODE (MD)
Port 7 Mode
0000
0000
†
P0_PIN (MC, MD)
P0_PIN (MH)
Port 0 Pin Input
Port 1 Pin Input
P1_PIN (MC, MD)
P1_PIN (MH)
†
P2_PIN
P3_PIN
P4_PIN
Port 2 Pin Input
Port 3 Pin Input
Port 4 Pin Input
Port 5 Pin Input
†
†
†
P5_PIN
1111
1111
†
Reset value is FFH when pin is not driven.
††
Reset value is 80H if the EA# pin is high, A9H if EA# is low.
††† The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after a device reset,
unless the device is entering programming modes (see “Entering Programming Modes” on page
16-13), in which case the programming chip configuration bytes (PCCBs) are used. The CCBs reside in
internal nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
C-3
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Table C-2. Register Name, Address, and Reset Status (Continued)
Binary Reset Value
Register
Mnemonic
Hex
Addr
Register Name
High
Low
P7_PIN (MD)
Port 7 Pin Input
1FD7
1F9D
1FD4
1FFC
1FFD
XXXX XXXX
P1_REG (MH)
P2_REG
Port 1 Data Output
Port 2 Data Output
Port 3 Data Output
Port 4 Data Output
1111
1111
1111
1111
1111
1111
1111
1111
†
P3_REG
P4_REG
P5_REG (MC, MD)
P5_REG (MH)
Port 5 Data Output
1FF5
1111
1111
1010
1010
1111
1111
1010
1010
P7_REG (MD)
PI_MASK
Port 7 Data Output
Peripheral Interrupt Mask
Peripheral Interrupt Pending
Programming Pulse Width
Processor Status Word
PTS Select
1FD5
1FBC
1FBE
PI_PEND
PPW
no direct
access
PSW
PTSSEL
0004
0006
1FB6
1FB4
1FB0
1FB2
1F80
1F88
1F82
1F8A
0018
1F84
1F8C
1F83
1F8B
1F81
1F89
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
PTSSRV
PTS Service
PWM_COUNT
PWM_PERIOD
PWM0_CONTROL
PWM1_CONTROL
SBUF0_RX (MH)
SBUF1_RX (MH)
SBUF0_TX (MH)
SBUF1_TX (MH)
SP
PWM Count
PWM Period
PWM 0 Control
PWM 1 Control
Serial Port Receive Buffer
Serial Port Receive Buffer
Serial Port Transmit Buffer
Serial Port Transmit Buffer
Stack Pointer
XXXX XXXX XXXX XXXX
SP0_BAUD (MH)
SP1_BAUD (MH)
SP0_CON (MH)
SP1_CON (MH)
SP0_STATUS (MH)
Serial Port 0 Baud Rate
Serial Port 1 Baud Rate
Serial Port Control
Serial Port Control
Serial Port Status
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
SP1_STATUS (MH)
Serial Port Status
†
Reset value is FFH when pin is not driven.
††
Reset value is 80H if the EA# pin is high, A9H if EA# is low.
††† The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after a device reset,
unless the device is entering programming modes (see “Entering Programming Modes” on page
16-13), in which case the programming chip configuration bytes (PCCBs) are used. The CCBs reside in
internal nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
C-4
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REGISTERS
Table C-2. Register Name, Address, and Reset Status (Continued)
Binary Reset Value
High Low
Register
Mnemonic
Hex
Addr
Register Name
T1CONTROL
Timer 1 Control
1F78
1F7C
1F72
1F7A
1F7E
0000
0000
0000
0000
T2CONTROL
T1RELOAD
TIMER1
Timer 2 Control
Timer 1 Reload
Timer 1 Value
Timer 2 Value
XXXX XXXX XXXX XXXX
0000
0000
0000
0000
0000
0000
0000
0000
0000
0010
TIMER2
USFR (MC, MD)
USFR (MH)
UPROM Special Function
1FF6
XXXX XXXX
XXXX XXXX
WATCHDOG
WG_COMP1
WG_COMP2
WG_COMP3
Watchdog Timer
000A
1FC2
1FC4
1FC6
Waveform Gen Phase Comp 1
Waveform Gen Phase Comp 2
Waveform Gen Phase Comp 3
0000
0000
0000
0000
1000
0000
0000
0000
0000
0000
0000
0000
0000
1100
0000
0000
0000
0000
0000
0000
WG_CONTROL (MC, MD)
WG_CONTROL (MH)
Waveform Gen Control
1FCC
WG_COUNTER
WG_OUTPUT
Waveform Gen Count
1FCA
1FC0
XXXX XXXX XXXX XXXX
Waveform Gen Output Config
0000
0000
0000
1111
0000
0000
0000
0000
0000
0000
WG_PROTECT (MC, MD)
WG_PROTECT (MH)
Waveform Gen Protection
1FCE
1110
0000
0000
0000
WG_RELOAD
WSR
Waveform Gen Reload
Window Selection
Zero Register
1FC8
0014
0000
0000
0000
0000
0000
ZERO_REG
†
Reset value is FFH when pin is not driven.
††
Reset value is 80H if the EA# pin is high, A9H if EA# is low.
††† The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after a device reset,
unless the device is entering programming modes (see “Entering Programming Modes” on page
16-13), in which case the programming chip configuration bytes (PCCBs) are used. The CCBs reside in
internal nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
C-5
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AD_COMMAND
Address:
Reset State:
1FACH
80H
AD_COMMAND
The A/D command (AD_COMMAND) register selects the A/D channel number to be converted,
controls whether the A/D converter starts immediately or with an EPA command, and selects the
conversion mode.
7
0
—
M1
M0
GO
ACH3
ACH2
ACH1
ACH0
Bit
Number
Bit
Mnemonic
Function
7
—
Reserved; for compatibility with future devices, write zeros to these bits.
6:5
M1:0
A/D Mode†
These bits determine the A/D mode.
M1
M0
Mode
0
0
1
1
0
1
0
1
10-bit conversion
8-bit conversion
threshold detect high
threshold detect low
4
GO
A/D Conversion Trigger††
Writing this bit arms the A/D converter. The value that you write to it
determines at what point a conversion is to start.
0 = EPA initiates conversion
1 = start immediately
3:0
ACH3:0
A/D Channel Selection
Write the A/D conversion channel number to these bits.
†
While a threshold-detection mode is selected for an analog input pin, no other conversion can be
started. If another value is loaded into AD_COMMAND, the threshold-detection mode is disabled
and the new command is executed.
††
It is the act of writing to the GO bit, rather than its value, that starts a conversion. Even if the GO bit
has the desired value, you must set it again to start a conversion immediately or clear it again to
arm it for an EPA-initiated conversion.
C-6
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REGISTERS
AD_RESULT (Read)
Address:
Reset State (MC, MD):
Reset State (MH):
1FAAH
FFC0H
7FC0H
AD_RESULT (Read)
The A/D result (AD_RESULT) register consists of two bytes. The high byte contains the eight most-
significant bits from the A/D converter. The low byte contains the two least-significant bits from a ten-
bit A/D conversion, indicates the A/D channel number that was used for the conversion, and indicates
whether a conversion is currently in progress.
15
ADRLT9
8
ADRLT8
ADRLT0
ADRLT7
—
ADRLT6
STATUS
ADRLT5
ACH3
ADRLT4
ACH2
ADRLT3
ACH1
ADRLT2
7
0
ADRLT1
ACH0
Bit
Number
Bit
Mnemonic
Function
15:6
ADRLT9:0
A/D Result
These bits contain the A/D conversion result.
Reserved. This bit is undefined.
A/D Status
5
4
—
STATUS
Indicates the status of the A/D converter. Up to 8 state times are required
to set this bit following a start command. When testing this bit, wait at
least the 8 state times.
0 = A/D is idle
1 = A/D conversion is in progress
3:0
ACH3:0
A/D Channel Number
These bits indicate the A/D channel number that was used for the
conversion.
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AD_RESULT (Write)
Address:
Reset State (MC, MD):
Reset State (MH):
1FAAH
FFC0H
7FC0H
AD_RESULT (Write)
The high byte of the A/D result (AD_RESULT) register can be written to set the reference voltage for
the A/D threshold-detection modes.
15
8
0
REFV7
—
REFV6
—
REFV5
—
REFV4
—
REFV3
—
REFV2
—
REFV1
—
REFV0
—
7
Bit
Number
Bit
Mnemonic
Function
15:8
REFV7:0
Reference Voltage
These bits specify the threshold value. This selects a reference voltage
that is compared with an analog input pin. When the voltage on the
analog input pin crosses over (detect high) or under (detect low) the
threshold value, the A/D conversion complete interrupt pending bit is set.
Use the following formula to determine the value to write to this register
for a given threshold voltage.
desired threshold voltage × 256
----------------------------------------------------------------------------------
reference voltage =
V
REF – ANGND
7:0
—
Reserved; for compatibility with future devices, write zeros to these bits.
C-8
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REGISTERS
AD_TEST
Address:
Reset State (MC, MD):
Reset State (MH):
1FAEH
C0H
AD_TEST
88H
The A/D test (AD_TEST) register specifies adjustments for DC offset errors.
7
0
—
—
—
OFF1
—
OFF0
—
—
Bit
Number
Bit
Mnemonic
Function
7:5
—
Reserved; for compatibility with future devices, write zeros to these bits.
4
OFF1
Offset
This bit , along with OFF0 (bit 2) allows you to set the zero offset point.
OFF1 OFF0
0
0
1
1
0
1
0
1
no adjustment
add 2.5 mV
subtract 2.5 mV
subtract 5.0 mV
3
—
Reserved; for compatibility with future devices, write zero to this bit.
See bit 4 (OFF1).
2
OFF0
—
1:0
Reserved; for compatibility with future devices, write zeros to these bits.
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AD_TIME
Address:
Reset State:
1FAFH
FFH
AD_TIME
The A/D time (AD_TIME) register programs the sample window time and the conversion time for each
bit. This register programs the speed at which the A/D can run — not the speed at which it can convert
correctly. Consult the data sheet for recommended values. Initialize the AD_TIME register before
initializing the AD_COMMAND register. Do not write to this register while a conversion is in progress;
the results are unpredictable.
7
0
SAM2
SAM1
SAM0
CONV4
CONV3
CONV2
CONV1
CONV0
Bit
Number
Bit
Mnemonic
Function
7:5
SAM2:0
A/D Sample Time
These bits specify the sample time. Use the following formula to
compute the sample time.
TSAM × FXTAL1 – 2
------------------------------------------------
SAM =
8
where:
SAM
=
=
=
1 to 7
TSAM
FXTAL1
the sample time, in µsec, from the data sheet
the input frequency on XTAL1, in MHz
4:0
CONV4:0
A/D Convert Time
These bits specify the conversion time for each bit. Use the following
formula to compute the conversion time.
TCONV ×FXTAL1 – 3
----------------------------------------------------
CONV =
where:
– 1
2 ×B
CONV= 2 to 31
TCONV
FXTAL1
B
=
=
=
the conversion time, in µsec, from the data sheet
the input frequency on XTAL1, in MHz
the number of bits to be converted (8 or 10)
C-10
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REGISTERS
CCR0
no direct access†
CCR0
The chip configuration 0 (CCR0) register controls powerdown mode, bus-control signals, and internal
memory protection. Three of its bits combine with two bits of CCR1 to control wait states and bus
width.
7
0
LOC1
LOC0
IRC1
IRC0
ALE
WR
BW0
PD
Bit
Number
Bit
Mnemonic
Function
7:6
LOC1:0
Lock Bits
These two bits control read and write access to the OTPROM during
normal operation. Refer to “Controlling Access to the OTPROM During
Normal Operation” on page 16-4 for details.
LOC1 LOC0
0
0
1
1
0
1
0
1
read and write protect
read protect only
write protect only
no protection
5:4
IRC1:0
Internal Ready Control
These two bits, along with IRC2 (CCR1.1) and the READY pin determine
the number of wait states that can be inserted into the bus cycle. While
READY is held low, wait states are inserted into the bus cycle until the
programmed number of wait states is reached. If READY is pulled high
before the programmed number of wait states is reached, no additional
wait states will be inserted into the bus cycle.
IRC2 IRC1 IRC0
0
0
1
1
1
1
1
0
X
1
0
0
1
1
0
1
X
0
1
0
1
zero wait states
illegal
illegal
one wait state
two wait states
three wait states
infinite
If you choose the infinite wait states option, you must keep P5.6
configured as the READY signal. Also, be sure to add external hardware
to count wait states and pull READY high within a specified time.
Otherwise, a defective external device could tie up the address/data bus
indefinitely.
†
The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after reset, unless the
microcontroller is entering programming modes (see “Entering Programming Modes” on page 16-13),
in which case the programming chip configuration bytes (PCCBs) are used. The CCBs reside in
nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
C-11
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CCR0
no direct access†
CCR0 (Continued)
The chip configuration 0 (CCR0) register controls powerdown mode, bus-control signals, and internal
memory protection. Three of its bits combine with two bits of CCR1 to control wait states and bus
width.
7
0
LOC1
LOC0
IRC1
IRC0
ALE
WR
BW0
PD
Bit
Number
Bit
Mnemonic
Function
Address Valid Strobe and Write Strobe
3
ALE
These bits define which bus-control signals will be generated during
external read and write cycles.
2
WR
ALE WR
0
0
1
1
0
1
0
1
address valid with write strobe mode
(ADV#, RD#, WRL#, WRH#)
address valid strobe mode
(ADV#, RD#, WR#, BHE#)
write strobe mode
(ALE, RD#, WRL#, WRH#)
standard bus-control mode
(ALE, RD#, WR#, BHE#)
1
BW0
Buswidth Control
This bit, along with the BW1 bit (CCR1.2), selects the bus width.
BW1 BW0
0
0
1
1
0
1
0
1
illegal
16-bit only
8-bit only
BUSWIDTH pin controlled
0
PD
Powerdown Enable
Controls whether the IDLPD #2 instruction causes the microcontroller to
enter powerdown mode. If your design uses powerdown mode, set this
bit when you program the CCBs. If it does not, clearing this bit when you
program the CCBs will prevent accidental entry into powerdown mode.
0 = disable powerdown mode
1 = enable powerdown mode
†
The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after reset, unless the
microcontroller is entering programming modes (see “Entering Programming Modes” on page 16-13),
in which case the programming chip configuration bytes (PCCBs) are used. The CCBs reside in
nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
C-12
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REGISTERS
CCR1
no direct access†
CCR1
The chip configuration 1 (CCR1) register enables the watchdog timer and selects the bus timing
mode. Two of its bits combine with three bits of CCR0 to control wait states and bus width.
7
0
1
1
0
1
WDE
BW1
IRC2
0
Bit
Number
Bit
Mnemonic
Function
7:6
1
To guarantee proper operation, write ones to these bits.
To guarantee proper operation, write zero to this bit.
To guarantee proper operation, write one to this bit.
Watchdog Timer Enable
5
4
3
0
1
WDE
Selects whether the watchdog timer is always enabled or enabled the
first time it is cleared.
0 = always enabled
1 = enabled first time it is cleared
2
BW1
Buswidth Control
This bit, along with the BW0 bit (CCR0.1), selects the bus width.
BW1 BW0
0
0
1
1
0
1
0
1
illegal
16-bit only
8-bit only
BUSWIDTH pin controlled
†
The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after reset, unless
the microcontroller is entering programming modes (see “Entering Programming Modes” on page
16-13), in which case the programming chip configuration bytes (PCCBs) are used. The CCBs
reside in nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
C-13
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CCR1
no direct access†
CCR1 (Continued)
The chip configuration 1 (CCR1) register enables the watchdog timer and selects the bus timing
mode. Two of its bits combine with three bits of CCR0 to control wait states and bus width.
7
0
1
1
0
1
WDE
BW1
IRC2
0
Bit
Number
Bit
Mnemonic
Function
1
IRC2
Ready Control
This bit, along with IRC0 (CCR0.4), IRC1 (CCR0.5), and the READY pin
determine the number of wait states that can be inserted into the bus
cycle. While READY is held low, wait states are inserted into the bus
cycle until the programmed number of wait states is reached. If READY is
pulled high before the programmed number of wait states is reached, no
additional wait states will be inserted into the bus cycle.
IRC2 IRC1 IRC0
0
0
1
1
1
1
1
0
X
1
0
0
1
1
0
1
X
0
1
0
1
zero wait states
illegal
illegal
one wait state
two wait states
three wait states
infinite
If you choose the infinite wait states option, you must keep P5.6
configured as the READY signal. Also, be sure to add external hardware
to count wait states and pull READY high within a specified time.
Otherwise, a defective external device could tie up the address/data bus
indefinitely.
0
0
Reserved; for compatibility with future devices, write zero to this bit.
†
The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after reset, unless
the microcontroller is entering programming modes (see “Entering Programming Modes” on page
16-13), in which case the programming chip configuration bytes (PCCBs) are used. The CCBs
reside in nonvolatile memory at addresses 2018H (CCB0) and 201AH (CCB1).
C-14
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REGISTERS
COMPx_CON
Address:
Reset State:
Table C-3
COMPx_CON
x = 0–3 (8XC196MC, MH)
x = 0–5 (8XC196MD)
The EPA compare control (COMPx_CON) registers determine the function of the EPA compare
channels.
7
0
0
x = 0, 2, 4
TB
TB
CE
CE
M1
M1
M0
M0
RE
RE
WGR
AD
ROT
ROT
RT
RT
7
x = 1, 3, 5
7
TB
Time Base Select
Specifies the reference timer.
0 = timer 1 is the reference timer and timer 2 is the opposite timer
1 = timer 2 is the reference timer and timer 1 is the opposite timer
A compare event (start of an A/D conversion; clearing, setting, or toggling
an output pin; and/or resetting either timer) occurs when the reference
timer matches the time programmed in the event-time register.
6
CE
Compare Enable
This bit enables the compare function.
0 = compare function disabled
1 = compare function enabled
5:4
M1:0
EPA Mode Select
Specifies the type of compare event.
M1
M0
0
0
1
1
0
1
0
1
no output
clear output pin
set output pin
toggle output pin
3
RE
Re-enable
Allows a compare event to continue to execute each time the event-time
register (COMPx_TIME) matches the reference timer rather than only
upon the first time match.
0 = compare function will drive the output only once
1 = compare function always enabled
C-15
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COMPx_CON
Address:
Reset State:
Table C-3
COMPx_CON (Continued)
x = 0–3 (8XC196MC, MH)
x = 0–5 (8XC196MD)
The EPA compare control (COMPx_CON) registers determine the function of the EPA compare
channels.
7
0
0
x = 0, 2, 4
TB
TB
CE
CE
M1
M1
M0
M0
RE
RE
WGR
AD
ROT
ROT
RT
RT
7
x = 1, 3, 5
2
WGR
AD
A/D Conversion, Waveform Generator Reload
The function of this bit depends on the EPA channel.
For EPA capture/compare channels 0, 2, 4:
The WGR bit allows you to use the EPA activities to cause the reload of
new values in the waveform generator.
0 = no action
1 = enables waveform generator reload
For EPA capture/compare channels 1, 3, 5:
The AD bit allows you to use the EPA activities to start an A/D
conversion that has been previously set up in the A/D control registers.
0 = causes no A/D action
1 = starts an A/D conversion on an output compare
1
0
ROT
Reset Opposite Timer
Selects the timer that is to be reset if the RT bit is set.
0 = selects the reference timer for possible reset
1 = selects the opposite timer for possible reset
The state of the TB bit determines which timer is the reference timer and
which timer is the opposite timer.
RT
Reset Timer
This bit controls whether the timer selected by the ROT bit will be reset.
1 = resets the timer selected by the ROT bit
0 = disables the reset function
C-16
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REGISTERS
COMPx_TIME
Address:
Reset State:
Table C-3
COMPx_TIME
x = 0–3 (8XC196MC, MH)
x = 0–5 (8XC196MD
The EPA compare x time (COMPx_TIME) registers are the event-time registers for the EPA compare
channels; they are functionally identically to the EPAx_TIME registers. The EPA triggers a compare
event when the reference timer matches the value in COMPx_TIME.
15
0
EPA Event Time Value
Bit
Number
Function
15:0
EPA Event Time Value
Write the desired compare event time to this register.
Table C-3. COMPx_TIME Addresses and Reset Values
Register
Address
Reset Value
COMP0_TIME (8XC196Mx)
COMP1_TIME (8XC196Mx)
COMP2_TIME (8XC196Mx)
1F5AH
1F5EH
1F62H
XXXXH
XXXXH
XXXXH
COMP3_TIME (8XC196MC, MD)
COMP3_TIME (8XC196MH)
1F66H
1F4EH
XXXXH
XXXXH
COMP4_TIME (8XC196MD)
COMP5_TIME (8XC196MD)
1F6AH
1F6EH
XXXXH
XXXXH
C-17
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EPAx_CON
Address:
Reset State:
Table C-4
EPAx_CON
x = 0–1 (8XC196MH)
x = 0–3 (8XC196MC)
x = 0–5 (8XC196MD)
The EPA control (EPAx_CON) registers control the functions of their assigned capture/compare
channels.
7
0
x = 0, 2, 4
x = 1, 3, 5
TB
TB
CE
CE
M1
M1
M0
M0
RE
WGR
AD
ROT
ROT
ON/RT
7
0
RE
ON/RT
Bit
Number
Bit
Mnemonic
Function
7
TB
Time Base Select
Specifies the reference timer.
0 = timer 1 is the reference timer and timer 2 is the opposite timer
1 = timer 2 is the reference timer and timer 1 is the opposite timer
A compare event (reloading the waveform generator; starting an A/D
conversion; clearing, setting, or toggling an output pin; and/or resetting
either timer) occurs when the reference timer matches the time
programmed in the event-time register.
When a capture event (falling edge, rising edge, or an edge change on
the EPAx pin) occurs, the reference timer value is saved in the EPA event-
time register (EPAx_TIME).
6
CE
Compare Enable
Determines whether the EPA channel operates in capture or compare
mode.
0 = capture mode
1 = compare mode
5:4
M1:0
EPA Mode Select
In capture mode, specifies the type of event that triggers an input capture.
In compare mode, specifies the action that the EPA executes when the
reference timer matches the event time.
M1
M0
Capture Mode Event
0
0
1
1
0
1
0
1
no capture
capture on falling edge
capture on rising edge
capture on either edge
M1
M0
Compare Mode Action
0
0
1
1
0
1
0
1
no output
clear output pin
set output pin
toggle output pin
C-18
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REGISTERS
EPAx_CON
Address:
Reset State:
Table C-4
EPAx_CON (Continued)
x = 0–1 (8XC196MH)
x = 0–3 (8XC196MC)
x = 0–5 (8XC196MD)
The EPA control (EPAx_CON) registers control the functions of their assigned capture/compare
channels.
7
0
x = 0, 2, 4
x = 1, 3, 5
TB
TB
CE
CE
M1
M1
M0
M0
RE
WGR
AD
ROT
ROT
ON/RT
7
0
RE
ON/RT
Bit
Number
Bit
Mnemonic
Function
3
RE
Re-enable
Re-enable applies to the compare mode only. It allows a compare event
to continue to execute each time the event-time register (EPAx_TIME)
matches the reference timer rather than only upon the first time match.
0 = compare function is disabled after a single event
1 = compare function always enabled
2
WGR
AD
Waveform Generator Reload; A/D Conversion
The function of this bit depends on the EPA channel.
For EPA capture/compare channels 0, 2, 4:
The WGR bit allows you to use the EPA activities to cause the reload
of new values in the waveform generator.
0 = no action
1 = enables waveform generator reload
For EPA capture/compare channels 1, 3, 5:
The AD bit allows you to use the EPA activities to start an A/D
conversion that has been previously set up in the A/D control
registers.
0 = causes no A/D action
1 = starts an A/D conversion on an output compare
1
ROT
Reset Opposite Timer
Controls different functions for capture and compare modes.
In Capture Mode:
0 = causes no action
1 = resets the opposite timer
In Compare Mode:
Selects the timer that is to be reset if the RT bit is set.
0 = selects the reference timer for possible reset
1 = selects the opposite timer for possible reset
The TB bit (bit 7) selects which is the reference timer and which is the
opposite timer.
C-19
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EPAx_CON
Address:
Reset State:
Table C-4
EPAx_CON (Continued)
x = 0–1 (8XC196MH)
x = 0–3 (8XC196MC)
x = 0–5 (8XC196MD)
The EPA control (EPAx_CON) registers control the functions of their assigned capture/compare
channels.
7
0
x = 0, 2, 4
x = 1, 3, 5
TB
TB
CE
CE
M1
M1
M0
M0
RE
WGR
AD
ROT
ROT
ON/RT
7
0
RE
ON/RT
Bit
Number
Bit
Mnemonic
Function
0
ON/RT
Overwrite New/Reset Timer
The ON/RT bit functions as overwrite new in capture mode and reset
timer in compare mode.
In Capture Mode (ON):
An overrun error is generated when an input capture occurs while the
event-time register (EPAx_TIME) and its buffer are both full. When an
overrun occurs, the ON bit determines whether old data is overwritten or
new data is ignored:
0 = ignores new data
1 = overwrites old data in the buffer
In Compare Mode (RT):
0 = disables the reset function
1 = resets the ROT-selected timer
Table C-4. EPAx_CON Addresses and Reset Values
Register
Address
Reset Value
EPA0_CON (8XC196Mx)
EPA1_CON (8XC196Mx)
EPA2_CON (8XC196MC, MD)
EPA3_CON (8XC196MC, MD)
EPA4_CON (8XC196MD)
EPA5_CON (8XC196MD)
1F40H
1F44H
1F48H
1F4CH
1F50H
1F54H
00H
00H
00H
00H
00H
00H
C-20
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REGISTERS
EPAx_TIME
Address:
Reset State:
Table C-5
EPAx_TIME
x = 0–1 (8XC196MH)
x = 0–3 (8XC196MC)
x = 0–5 (8XC196MD)
The EPA time (EPAx_TIME) registers are the event-time registers for the EPA channels. In capture
mode, the value of the reference timer is captured in EPAx_TIME when an input transition occurs.
Each event-time register is buffered, allowing the storage of two capture events at once. In compare
mode, the EPA triggers a compare event when the reference timer matches the value in EPAx_TIME.
EPAx_TIME is not buffered for compare mode.
15
0
EPA Timer Value
Bit
Number
Function
15:0
EPA Timer Value
When an EPA channel is configured for capture mode, this register contains the value of
the reference timer when the specified event occurred.
When an EPA channel is configured for compare mode, write the compare event time to
this register.
Table C-5. EPAx_TIME Addresses and Reset Values
Register
Address
Reset Value
EPA0_TIME (8XC196Mx)
EPA1_TIME (8XC196Mx)
EPA2_TIME (8XC196MC, MD)
EPA3_TIME (8XC196MC, MD)
EPA4_TIME (8XC196MD)
EPA5_TIME (8XC196MD)
1F42H
1F46H
1F4AH
1F4EH
1F52H
1F56H
XXXXH
XXXXH
XXXXH
XXXXH
XXXXH
XX00H
C-21
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FREQ_CNT
Address:
Reset State:
1FBAH
00H
FREQ_CNT
(8XC196MD)
Read the frequency generator count (FREQ_CNT) register to determine the current value of the
down-counter.
7
0
8XC196MD
Count
Bit
Number
Function
7:0
Count
This register contains the current down-counter value.
C-22
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REGISTERS
FREQ_GEN
Address:
Reset State:
1FB8H
00H
FREQ_GEN
(8XC196MD)
The frequency (FREQ_GEN) register holds a programmed value that specifies the output frequency.
This value is reloaded into the down-counter each time the counter reaches 0.
7
0
8XC196MD
Output Frequency
Bit
Number
Function
7:0
Output Frequency
Use the following formula to calculate the FREQ value for the desired output frequency
and write this value to the frequency register.
FXTAL1
--------------------------------------------
FREQ =
– 1
16 ×
FREQ_OUT
where:
FREQ
FXTAL1
FREQ_OUT
=
=
=
8-bit value to load into FREQ_GEN register
input frequency on XTAL1 pin, in MHz
output frequency on FREQOUT pin, in MHz
C-23
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GEN_CON
Address:
Reset State:
1FA0H
00H
GEN_CON
(8XC196MH)
The GEN_CON register controls whether an internal reset asserts the external RESET# signal and
indicates the source of the most recent reset.
7
0
8XC196MH
RSTS
—
—
—
—
—
—
DR0
Bit
Number
Bit
Mnemonic
Function
7
RSTS
Reset source (read-only status bit)
0 = external reset (RESET# pin asserted)
1 = internal reset (watchdog overflow, illegal IDLPD key, or RST
instruction)
6:1
0
—
Reserved; for compatibility with future devices, write zeros to these bits.
DRO
Disable RESET# out
0 = an internal reset asserts the RESET# pin.
1 = an internal reset has no effect on the RESET# pin; the RESET# pin is
pulled high (inactive).
C-24
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REGISTERS
INT_MASK
Address:
Reset State:
0008H
00H
INT_MASK
The interrupt mask (INT_MASK) register enables or disables (masks) individual interrupt requests.
(The EI and DI instructions enable and disable servicing of all maskable interrupts.) INT_MASK is the
low byte of the processor status word (PSW). PUSHF or PUSHA saves the contents of this register
onto the stack and then clears this register. Interrupt calls cannot occur immediately following this
instruction. POPF or POPA restores it.
7
0
MC, MD
MH
COMP2
EPA2
COMP1
EPA1
EPA1
COMP0
COMP0
EPA0
EPA0
AD
AD
OVRTM
7
0
COMP3 COMP2 COMP1
OVRTM
Bit
Number
Function
7:0
Setting a bit enables the corresponding interrupt.
The standard interrupt vector locations are as follows:
Bit Mnemonic
COMP2 (MC, MD) EPA Compare-only Channel 2
Interrupt
Standard Vector
200EH
COMP3 (MH)
EPA2 (MC, MD)
COMP2 (MH)
COMP1
EPA Compare-only Channel 3
EPA Capture/Compare Channel 2
EPA Compare Channel 2
200EH
200CH
200EH
EPA Compare Channel 1
200AH
EPA1
EPA Capture/Compare Channel 1
2008H
COMP0
EPA Compare Channel 0
2006H
EPA0
AD
OVRTM†
EPA Capture/Compare Channel 0
A/D Conversion Complete
Overflow/Underflow Timer
2004H
2002H
2000H
†
Both timer 1 and timer 2 can generate the multiplexed overflow/underflow interrupt. Write
to PI_MASK to enable the interrupt sources; read PI_PEND to determine which source
caused the interrupt.
C-25
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INT_MASK1
Address:
Reset State:
0013H
00H
INT_MASK1
The interrupt mask 1 (INT_MASK1) register enables or disables (masks) individual interrupt requests.
(The EI and DI instructions enable and disable servicing of all maskable interrupts.) INT_MASK1 can
be read from or written to as a byte register. PUSHA saves this register on the stack and POPA
restores it.
7
7
7
0
8XC196MC
8XC196MD
8XC196MH
NMI
NMI
NMI
EXTINT
EXTINT
EXTINT
PI
PI
—
—
COMP4
RI1
—
COMP3
COMP3
TI1
EPA3
EPA3
TI0
0
0
EPA5
SPI
EPA4
RI0
WG
Bit
Number
Function
7:0†
Setting a bit enables the corresponding interrupt.
The standard interrupt vector locations are as follows:
Bit Mnemonic
NMI
EXTINT
PI (MC, MD)††
WG (MH)
EPA5 (MD)
SPI (MH)†††
COMP4 (MD)
RI1 (MH)
Interrupt
Nonmaskable Interrupt
EXTINT pin
Multiplexed Peripheral Interrupt
Waveform Generator
EPA Capture/Compare Channel 5
Serial Port
EPA Compare Channel 4
SIO 1 Receive
Standard Vector
203EH
203CH
203AH
203AH
2038H
2038H
2036H
2036H
EPA4 (MD)
RI0 (MH)
EPA Capture/Compare Channel 4
SIO 0 Receive
2034H
2034H
COMP3 (MC, MD) EPA Compare Channel 3
2032H
TI1 (MH)
SIO 1 Transmit
2032H
EPA3 (MC, MD)
TI0 (MH)
EPA Capture/Compare Channel 3
SIO 0 Transmit
2030H
2030H
††
The waveform generator and the EPA compare-only channel 5 can generate this
interrupt. Write to PI_MASK to enable the interrupt sources; read PI_PEND to
determine which source caused the interrupt.
††† SIO 0 and SIO 1 can generate this interrupt. Write to PI_MASK to enable the interrupt
sources; read PI_PEND to determine which source caused the interrupt.
†
On the 8XC196MC device bits 4–3 are reserved. For compatibility with future devices, write zeros to
these bits.
C-26
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REGISTERS
INT_PEND
Address:
Reset State:
0009H
00H
INT_PEND
When hardware detects an interrupt request, it sets the corresponding bit in the interrupt pending
(INT_PEND or INT_PEND1) registers. When the vector is taken, the hardware clears the pending bit.
Software can generate an interrupt by setting the corresponding interrupt pending bit.
7
0
MC, MD
MH
COMP2
EPA2
COMP1
EPA1
EPA1
COMP0
COMP0
EPA0
EPA0
AD
AD
OVRTM
7
0
COMP3 COMP2 COMP1
OVRTM
Bit
Number
Function
7:0
Any set bit indicates that the corresponding interrupt is pending. The interrupt bit is cleared
when processing transfers to the corresponding interrupt vector.
The standard interrupt vector locations are as follows:
Bit Mnemonic
COMP2 (MC, MD) EPA Compare Channel 2
Interrupt
Standard Vector
200EH
COMP3 (MH)
EPA2 (MC, MD)
COMP2 (MH)
COMP1
EPA Compare Channel 3
EPA Capture/Compare Channel 2
EPA Compare Channel 2
EPA Compare Channel 1
200EH
200CH
200EH
200AH
EPA1
COMP0
EPA Capture/Compare Channel 1
EPA Compare Channel 0
2008H
2006H
EPA0
AD
OVRTM†
EPA Capture/Compare Channel 0
A/D Conversion Complete
Overflow/Underflow Timer
2004H
2002H
2000H
†
Timer 1 and timer 2 can generate the multiplexed overflow/underflow interrupt. Write to
PI_MASK to enable the interrupt sources; read PI_PEND to determine which source
caused the interrupt.
C-27
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INT_PEND1
Address:
Reset State:
0012H
00H
INT_PEND1
When hardware detects a pending interrupt, it sets the corresponding bit in the interrupt pending
(INT_PEND or INT_PEND1) registers. When the vector is taken, the hardware clears the pending bit.
Software can generate an interrupt by setting the corresponding interrupt pending bit.
7
7
7
0
8XC196MC
8XC196MD
8XC196MH
NMI
NMI
NMI
EXTINT
EXTINT
EXTINT
PI
PI
—
—
COMP4
RI1
—
COMP3
COMP3
TI1
EPA3
EPA3
TI0
0
0
EPA5
SPI
EPA4
RI0
WG
Bit
Number
Function
7:0†
Setting a bit enables the corresponding interrupt.
The standard interrupt vector locations are as follows:
Bit Mnemonic
NMI
EXTINT
PI (MC, MD)††
WG (MH)
EPA5 (MD)
SPI (MH)†††
COMP4 (MD)
RI1 (MH)
Interrupt
Nonmaskable Interrupt
EXTINT pin
Multiplexed Peripheral Interrupt
Waveform Generator
EPA Capture/Compare Channel 5
Serial Port
EPA Compare Channel 4
SIO 1 Receive
Standard Vector
203EH
203CH
203AH
203AH
2038H
2038H
2036H
2036H
EPA4 (MD)
RI0 (MH)
EPA Capture/Compare Channel 4
SIO 0 Receive
2034H
2034H
COMP3 (MC, MD) EPA Compare Channel 3
2032H
TI1 (MH)
SIO 1 Transmit
2032H
EPA3 (MC, MD)
EPA Capture/Compare Channel 3
2030H
TI0 (MH)
SIO 0 Transmit
2030H
††
On the 8XC196MD, the waveform generator and the EPA compare channel 5 can
generate this interrupt. Write to PI_MASK to enable the interrupt sources; read
PI_PEND to determine which source caused the interrupt. On the 8XC196MC, the
waveform generator is the sole source for this interrupt.
††† SIO 0 and SIO 1 can generate this interrupt. Write to PI_MASK to enable the interrupt
sources; read PI_PEND to determine which source caused the interrupt.
†
On the 8XC196MC device bits 4–3 are reserved. These bits are undefined.
C-28
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REGISTERS
ONES_REG
Address:
Reset State:
02H
FFFFH
ONES_REG
The two-byte ones register (ONES_REG) is always equal to FFFFH. It is useful as a fixed source of all
ones for comparison operations.
15
0
One
Bit
Number
Function
15:0
One
These bits are always equal to FFFFH.
C-29
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8XC196MC, MD, MH USER’S MANUAL
Px_DIR
Address:
Reset State:
Table C-6
Px_DIR
x = 2, 5 (8XC196MC)
x = 2, 5, 7 (8XC196MD)
x = 1, 2, 5 (8XC196MH)
Each pin of port x can operate in any of the standard I/O modes of operation: complementary output,
open-drain output, or high-impedance input. The port x I/O direction (Px_DIR) register determines the
I/O direction for each port x pin. The register settings for an open-drain output or a high-impedance
input are identical. An open-drain output configuration requires an external pull-up. A high-impedance
input configuration requires that the corresponding bit in Px_REG be set.
7
7
7
0
x = 1 (MH)
x = 2, 5 (Mx)
x = 7 (MD)
—
—
—
—
PIN3
PIN3
PIN3
PIN2
PIN2
PIN2
PIN1
PIN1
PIN1
PIN0
PIN0
PIN0
0
0
PIN7
PIN7
PIN6
PIN6
PIN5
PIN5
PIN4
PIN4
Bit
Number
Bit
Mnemonic
Function
7:0†
PIN7:0
Port x Pin y Direction
This bit selects the Px.y direction:
0 = complementary output (output only)
1 = input or open-drain output (input, output, or bidirectional open-
drain outputs require external pull-ups.
†
The bits shown as dashes (—) are reserved; for compatibility with future devices, write ones to these
bits.
Table C-6. Px_DIR Addresses and Reset Values
Register
Address
Reset Value
P1_DIR (8XC196MH)
P2_DIR (8XC196Mx)
P5_DIR (8XC196Mx)
P7_DIR (8XC196MD)
1F9BH
1FD2H
1FF3H
1FD3H
FFH
FFH
FFH
FFH
C-30
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REGISTERS
Px_MODE
Address:
Reset State:
Table C-7
Px_MODE
x = 2, 5 (8XC196MC)
x = 2, 5, 7 (8XC196MD)
x = 1, 2, 5 (8XC196MH)
Each bit of the port x mode (Px_MODE) register controls whether the corresponding pin functions as a
standard I/O port pin or as a special-function signal.
7
0
x = 1 (MH)
x = 2, 5 (Mx)
x = 7 (MD)
—
—
—
—
PIN3
PIN3
PIN3
PIN2
PIN2
PIN2
PIN1
PIN1
PIN1
PIN0
PIN0
PIN0
7
0
0
PIN7
PIN6
PIN6
PIN5
PIN5
PIN4
PIN4
7
PIN7
Bit
Number
Bit
Mnemonic
Function
7:0†
PIN7:0
Port x Pin y Mode
This bit determines the mode of the corresponding port pin:
0 = standard I/O port pin
1 = special-function signal
Table C-8 lists the special-function signals for each pin.
†
The bits shown as dashes (—) are reserved; for compatibility with future devices, write zeros to these
bits.
Table C-7. Px_MODE Addresses and Reset Values
Register
Address
Reset Value
P1_MODE (8XC196MH)
P2_MODE (8XC196Mx)
1F99H
1FD0H
00H
00H
P5_MODE (8XC196MC, MD)
P5_MODE (8XC196MH)
1FF1H
1FF1H
FFH when pin is not driven
80H if the EA# pin is high, A9H if EA# is low
P7_MODE (8XC196MD)
1FD1H
00H
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Px_MODE
Table C-8. Special-function Signals for Ports 1, 2, 5, 6
Port 1
Port 2
Port 2
(8XC196MH)
(8XC196MC, MD)
(8XC196MH)
Special-function
Signal
Special-function
Special-function
Signal
Pin
P1.0
Pin
P2.0
Pin
P2.0
Signal
TXD0
RXD0
TXD1
RXD1
EPA0/PVER
EPA1/PALE#
EPA2/PROG#
EPA3
EPA0/PVER
P1.1
P1.2
P1.3
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
SCLK0#/BCLK0/PALE#
EPA1/PROG#
COMP3
COMP0/AINC#
COMP1/PACT#
COMP2/CPVER
COMP3
COMP0/AINC#
COMP1/PACT#
COMP2/CPVER
SCLK1#BCLK1
Port 5
Port 7
(8XC196Mx)
(8XC196MD)
Special-function
Signal
Special-function
Signal
Pin
Pin
P5.0
P5.1
P5.2
P5.3
P5.4
P5.5
P5.6
P5.7
ALE/ADV#
INST
P7.0
P7.1
P7.2
P7.3
P7.4
P7.5
P7.6
P7.7
EPA4
EPA5
COMP4
COMP5
—
WR#/WRL#
RD#
ONCE#
BHE#/WRH#
READY
—
—
BUSWIDTH
FREQOUT
C-32
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REGISTERS
Px_PIN
Address:
Reset State:
Table C-9
Px_PIN
x = 0–5 (8XC196MC, MH)
x = 0–5, 7 (8XC196MD)
Each bit of the port x pin input (Px_PIN) register reflects the current state of the corresponding pin,
regardless of the pin configuration.
7
0
0
0
0
x = 1 (MC)
—
—
—
—
—
—
PIN4
—
PIN3
PIN3
PIN3
PIN3
PIN2
PIN2
PIN2
PIN2
PIN1
PIN1
PIN1
PIN1
PIN0
PIN0
PIN0
PIN0
7
7
7
x = 1 (MH)
x = 1, 7 (MD)
x = 0, 2–5 (Mx)
PIN7
PIN7
PIN6
PIN6
PIN5
PIN5
PIN4
PIN4
Bit
Mnemonic
Bit Number
Function
7:0†
PIN7:0
Port x Pin y Input Value
This bit contains the current state of Px.y.
The bits shown as dashes (—) are reserved; their values are undefined.
†
Table C-9. Px_PIN Addresses and Reset Values
Register
Address
Reset Value
P0_PIN (8XC196MC, MD)
P0_PIN (8XC196MH)
1FA8H
1FDAH
FFH when pin is not driven
FFH when pin is not driven
P1_PIN (8XC196MC, MD)
P1_PIN (8XC196MH)
1FA9H
1F9FH
P2_PIN (8XC196Mx)
P3_PIN (8XC196Mx)
P4_PIN (8XC196Mx)
1FD6H
1FFEH
1FFFH
FFH when pin is not driven
FFH when pin is not driven
FFH when pin is not driven
P5_PIN (8XC196MC, MD)
P5_PIN (8XC196MH)
1FF7H
1FF7H
FFH
FFH when pin is not driven
P7_PIN (8XC196MD)
1FD7H
XXH
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Px_REG
Address: Table C-10
Reset State:
Px_REG
x = 2–5 (8XC196MC)
x = 2–5, 7 (8XC196MD)
x = 1–5 (8XC196MH)
For an input, set the corresponding port x data output (Px_REG) register bit.
For an output, write the data to be driven out by each pin to the corresponding bit of Px_REG. When a
pin is configured as standard I/O (Px_MODE.y = 0), the result of a CPU write to Px_REG is
immediately visible on the pin. When a pin is configured as a special-function signal (Px_MODE.y = 1),
the associated on-chip peripheral or off-chip component controls the pin. The CPU can still write to
Px_REG, but the pin is unaffected until it is switched back to its standard I/O function.
This feature allows software to configure a pin as standard I/O (clear Px_MODE.y), initialize or
overwrite the pin value, then configure the pin as a special-function signal (set Px_MODE.y). In this
way, initialization, fault recovery, exception handling, etc., can be done without changing the operation
of the associated peripheral.
7
7
7
0
x = 1 (MH)
x = 2–5 (Mx)
x = 7 (MD)
—
—
—
—
PIN3
PIN3
PIN3
PIN2
PIN2
PIN2
PIN1
PIN1
PIN1
PIN0
PIN0
PIN0
0
0
PIN7
PIN7
PIN6
PIN6
PIN5
PIN5
PIN4
PIN4
Bit
Mnemonic
Bit Number
Function
7:0†
PIN7:0
Port x Pin y Output
To use Px.y for output, write the desired output data to this bit. To use
Px.y for input, set this bit.
†
The bits shown as dashes (—) are reserved; for compatibility with future devices, write zeros to
these bits.
Table C-10. Px_REG Addresses and Reset Values
Register
Address
Reset Value
P1_REG (8XC196MH)
P2_REG (8XC196Mx)
P3_REG (8XC196Mx)
P4_REG (8XC196Mx)
1F9DH
1FD4H
1FFCH
1FFDH
FFH
FFH
FFH
FFH
P5_REG (8XC196MC, MD)
P5_REG (8XC196MH)
1FF5H
1FF5H
FFH when pin is not driven
FFH
P7_REG (8XC196MD)
1FD5H
FFH
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REGISTERS
PI_MASK
Address:
Reset State:
1FBCH
AAH
PI_MASK
The peripheral interrupt mask (PI_MASK) register enables or disables (masks) interrupt requests
associated with the peripheral interrupt (PI), the serial port interrupt (SPI), and the overflow/underflow
timer interrupt (OVRTM).
7
7
7
0
—
—
—
—
—
—
—
WG
WG
SP0
—
—
—
OVRTM2
OVRTM2
OVRTM2
—
—
—
OVRTM1
8XC196MC
8XC196MD
8XC196MH
0
COMP5
SP1
OVRTM1
0
OVRTM1
Bit
Number
Bit
Mnemonic
Function
7, 5, 3, 1
6
—
Reserved; for compatibility with future devices, write zeros to these bits.
Reserved; for compatibility with future devices, write zero to this bit.
— (MC)
COMP5 (MD) EPA Compare Channel 5
Setting this bit enables the EPA compare channel 5 interrupt.
The EPA compare channel 5 and the waveform generator interrupts are
associated with the peripheral interrupt (PI). Setting INT_MASK1.5
enables PI.
SP1 (MH)
Serial Port 1 Error
Setting this bit enables the serial port 1 error interrupt.
The serial port 1 and serial port 0 error interrupts are associated with the
serial port interrupt (SPI). Setting INT_MASK1.4 enables SPI.
4
WG (MC, MD) Waveform Generator
Setting this bit enables the waveform generator interrupt.
The waveform generator and the EPA compare channel 5 interrupts are
associated with the peripheral interrupt (PI). Setting INT_MASK1.5
enables PI.
SP0 (MH)
OVRTM2
Serial Port 0 Error
Setting this bit enables the serial port 0 error interrupt.
The serial port 0 and serial port 1 error interrupts are associated with the
serial port interrupt (SPI). Setting INT_MASK1.4 enables SPI.
2
Timer 2 Overflow/Underflow
Setting this bit enables the timer 2 overflow/underflow interrupt.
The timer 2 and timer 1 overflow/underflow interrupts are associated with
the overflow/underflow timer interrupt (OVRTM). Setting INT_MASK.0
enables OVRTM.
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PI_MASK
Address:
Reset State:
1FBCH
AAH
PI_MASK (Continued)
The peripheral interrupt mask (PI_MASK) register enables or disables (masks) interrupt requests
associated with the peripheral interrupt (PI), the serial port interrupt (SPI), and the overflow/underflow
timer interrupt (OVRTM).
7
7
7
0
—
—
—
—
—
—
—
WG
WG
SP0
—
—
—
OVRTM2
OVRTM2
OVRTM2
—
—
—
OVRTM1
8XC196MC
8XC196MD
8XC196MH
0
COMP5
SP1
OVRTM1
0
OVRTM1
Bit
Number
Bit
Mnemonic
Function
0
OVRTM1
Timer 1 Overflow/Underflow
Setting this bit enables the timer 1 overflow/underflow interrupt.
The timer 1 and timer 2 overflow/underflow interrupts are associated with
the overflow/underflow timer interrupt (OVRTM). Setting INT_MASK.0
enables OVRTM.
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REGISTERS
PI_PEND
Address:
Reset State:
1FBEH
AAH
PI_PEND
When hardware detects a pending peripheral or timer interrupt, it sets the corresponding bit in the
interrupt pending (INT_PEND or INT_PEND1) registers and the peripheral interrupt pending
(PI_PEND) register. When the vector is taken, the hardware clears the INT_PEND/INT_PEND1
pending bit. Reading this register clears all the PI_PEND bits. Software can generate an interrupt by
setting a PI_PEND bit.
7
0
—
—
—
—
—
—
—
WG
WG
SP0
—
—
—
OVRTM2
OVRTM2
OVRTM2
—
—
—
OVRTM1
8XC196MC
8XC196MD
8XC196MH
7
7
0
COMP5
SP1
OVRTM1
0
OVRTM1
Bit
Number
Bit
Mnemonic
Function
7, 5, 3, 1
6
—
Reserved. These bits are undefined.
Reserved. This bit is undefined.
— (MC)
COMP5 (MD) EPA Compare Channel 5
When set, this bit indicates a pending EPA compare channel 5 interrupt.
The EPA compare channel 5 and the waveform generator interrupts are
associated with the peripheral interrupt (PI). Setting INT_MASK1.5
enables PI. Setting PI_MASK.6 enables COMP5.
SP1 (MH)
Serial Port 1 Error
When set, this bit indicates a pending serial port 1 error interrupt.
The serial port 1 and 0 error interrupts are associated with the serial port
interrupt (SPI). Setting INT_MASK1.4 enables SPI. Setting PI_MASK.6
enables SP1.
4
WG (MC, MD) Waveform Generator
When set, this bit indicates a pending waveform generator interrupt.
The waveform generator and the EPA compare channel 5 interrupts are
associated with the peripheral interrupt (PI). Setting INT_MASK1.5
enables PI. Setting PI_MASK.5 enables WG.
SP0 (MH)
OVRTM2
Serial Port 0 Error
When set, this bit indicates a pending serial port 0 error interrupt.
The serial port 0 and 1 error interrupts are associated with the serial port
interrupt (SPI). Setting INT_MASK1.4 enables SPI. Setting PI_MASK.4
enables SP0.
2
Timer 2 Overflow/Underflow
When set, this bit indicates a pending timer 2 overflow/underflow interrupt.
The timer 2 and timer 1 overflow/underflow interrupts are associated with
the overflow/underflow timer interrupt (OVRTM). Setting INT_MASK.0
enables OVRTM. Setting PI_MASK.2 enables OVRTM2.
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PI_PEND
Address:
Reset State:
1FBEH
AAH
PI_PEND (Continued)
When hardware detects a pending peripheral or timer interrupt, it sets the corresponding bit in the
interrupt pending (INT_PEND or INT_PEND1) registers and the peripheral interrupt pending
(PI_PEND) register. When the vector is taken, the hardware clears the INT_PEND/INT_PEND1
pending bit. Reading this register clears all the PI_PEND bits. Software can generate an interrupt by
setting a PI_PEND bit.
7
0
—
—
—
—
—
—
—
WG
WG
SP0
—
—
—
OVRTM2
OVRTM2
OVRTM2
—
—
—
OVRTM1
8XC196MC
8XC196MD
8XC196MH
7
7
0
COMP5
SP1
OVRTM1
0
OVRTM1
Bit
Number
Bit
Mnemonic
Function
0
OVRTM1
Timer 1 Overflow/Underflow
When set, this bit indicates a pending timer 1 overflow/underflow interrupt.
The timer 1 and timer 2 overflow/underflow interrupts are associated with
the overflow/underflow timer interrupt (OVRTM). Setting INT_MASK.0
enables OVRTM. Setting PI_MASK.0 enables OVRTM1.
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REGISTERS
PPW
no direct access
PPW
The programming pulse width (PPW) register is loaded from the external EPROM (locations 14H and
15H for the 8XC196MC and MD; locations 4014H and 4015H for the 8XC196MH) in auto programming
mode. The PPW_VALUE determines the programming pulse width.
15
PPW15
8
PPW14
PPW6
PPW13
PPW5
PPW12
PPW4
PPW11
PPW3
PPW10
PPW2
PPW9
PPW1
PPW8
PPW0
7
0
PPW7
Bit
Bit
Function
Number Mnemonic
15:0 PPW15:0
PPW_VALUE
This value establishes the programming pulse width for auto programming.
Use the appropriate formula to calculate the PPW_VALUE, then write the
result to the PPW register.
PPW_VALUE for 8XC196MC, MD = 62.5 ×FXTAL1
PPW_VALUE for 8XC196MH
= 25 ×FXTAL1
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PSW
no direct access
PSW
The processor status word (PSW) actually consists of two bytes. The high byte is the status word,
which is described here; the low byte is the INT_MASK register. The status word contains one bit
(PSW.1) that globally enables or disables servicing of all maskable interrupts, one bit (PSW.2) that
enables or disables the peripheral transaction server (PTS), and six Boolean flags that reflect the
state of a user’s program.
The status word portion of the PSW cannot be accessed directly. To access the status word, push the
value onto the stack (PUSHF), then pop the value to a register (POP test_reg). The PUSHF and
PUSHA instructions save the PSW in the system stack and then clear it; POPF and POPA restore it.
15
8
Z
N
V
VT
C
PSE
I
ST
7
0
See INT_MASK on page C-25
Bit
Number
Bit
Mnemonic
Function
15
Z
Zero Flag
This flag is set to indicate that the result of an operation was zero. For
multiple-precision calculations, the zero flag cannot be set by the instruc-
tions that use the carry bit from the previous calculation (e.g., ADDC,
SUBC). However, these instructions can clear the zero flag. This
ensures that the zero flag will reflect the result of the entire operation, not
just the last calculation. For example, if the result of adding together the
lower words of two double words is zero, the zero flag would be set.
When the upper words are added together using the ADDC instruction,
the flag remains set if the result is zero and is cleared if the result is not
zero.
14
13
N
V
Negative Flag
This flag is set to indicate that the result of an operation is negative. The
flag is correct even if an overflow occurs. For all shift operations and the
NORML instruction, the flag is set to equal the most-significant bit of the
result, even if the shift count is zero.
Overflow Flag
This flag is set to indicate that the result of an operation is too large to be
represented correctly in the available space. For shift operations (SHL,
SHLB, and SHLL), the flag is set if the most-significant bit of the operand
changes during the shift. For divide operations, the quotient is stored in
the low-order half of the destination operand and the remainder is stored
in the high-order half. The overflow flag is set if the quotient is outside
the range for the low-order half of the destination operand. (Chapter 3,
“Programming Considerations,” defines the operands and possible
values for each. See the PSW flag descriptions in Appendix A for
details.)
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REGISTERS
PSW
no direct access
PSW (Continued)
The processor status word (PSW) actually consists of two bytes. The high byte is the status word,
which is described here; the low byte is the INT_MASK register. The status word contains one bit
(PSW.1) that globally enables or disables servicing of all maskable interrupts, one bit (PSW.2) that
enables or disables the peripheral transaction server (PTS), and six Boolean flags that reflect the
state of a user’s program.
The status word portion of the PSW cannot be accessed directly. To access the status word, push the
value onto the stack (PUSHF), then pop the value to a register (POP test_reg). The PUSHF and
PUSHA instructions save the PSW in the system stack and then clear it; POPF and POPA restore it.
15
8
Z
N
V
VT
C
PSE
I
ST
7
0
See INT_MASK on page C-25
Bit
Number
Bit
Mnemonic
Function
12
VT
Overflow-trap Flag
This flag is set when the overflow flag is set, but it is cleared only by the
CLRVT, JVT, and JNVT instructions. This allows testing for a possible
overflow at the end of a sequence of related arithmetic operations, which
is generally more efficient than testing the overflow flag after each
operation.
11
C
Carry Flag
This flag is set to indicate an arithmetic carry or the last bit shifted out of
an operand. It is cleared if a subtraction operation generates a borrow.
Normally, the result is rounded up if the carry flag is set. The sticky bit
flag allows a finer resolution in the rounding decision. (See the PSW flag
descriptions in Appendix A for details.)
10
9
PSE
PTS Enable
This bit globally enables or disables the peripheral transaction server
(PTS). The EPTS instruction sets this bit; DPTS clears it.
0 = disable PTS
1 = enable PTS
I
Interrupt Disable (Global)
This bit globally enables or disables the servicing of all maskable
interrupts. The bits in INT_MASK and INT_MASK1 individually enable or
disable the interrupts. The EI instruction sets this bit; DI clears it.
0 = disable interrupt servicing
1 = enable interrupt servicing
8
ST
Sticky Bit Flag
This flag is set to indicate that, during a right shift, a “1” was shifted into
the carry flag and then shifted out. It can be used with the carry flag to
allow finer resolution in rounding decisions.
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PTSSEL
Address:
Reset State:
0004H
0000H
PTSSEL
The PTS select (PTSSEL) register selects either a PTS microcode routine or a standard interrupt
service routine for each interrupt request. Setting a bit selects a PTS microcode routine; clearing a bit
selects a standard interrupt service routine. When PTSCOUNT reaches zero, hardware clears the
corresponding PTSSEL bit. The PTSSEL bit must be set manually to re-enable the PTS channel.
15
8
0
8XC196MC
8XC196MD
8XC196MH
—
EXTINT
EPA2
PI
—
—
—
COMP3
AD
EPA3
7
COMP2
COMP1
EPA1
COMP0
EPA0
OVRTM
15
8
—
7
EXTINT
EPA2
PI
EPA5
EPA1
COMP4
COMP0
EPA4
EPA0
COMP3
AD
EPA3
0
COMP2
COMP1
OVRTM
15
—
7
8
EXTINT
WG
SPI
RI1
RI0
TI1
AD
TI0
0
COMP3 COMP2 COMP1
EPA1
COMP0
EPA0
OVRTM
Bit
Number
Function
Reserved; for compatibility with future devices, write zero to this bit.
15
14:0†
Setting a bit causes the corresponding interrupt to be handled by a PTS microcode routine.
The PTS interrupt vector locations are as follows:
Bit Mnemonic
EXTINT
PTS Vector
205CH
205AH
205AH
2058H
2058H
2056H
2056H
2054H
2054H
Bit Mnemonic
TI0 (MH)
PTS Vector
2050H
204EH
204EH
204CH
204CH
204AH
2048H
2046H
2044H
2042H
2040H
PI (MC, MD)††
WG (MH)
COMP2 (MC,MD)
COMP3 (MH)
EPA2 (MC, MD)
COMP2 (MH)
COMP1
EPA1
COMP0
EPA0
AD
OVRTM††
EPA5 (MD)
SPI (MH)††
COMP4 (MD)
RI1 (MH)
EPA4 (MD)
RI0 (MH)
COMP3 (MC, MD) 2052H
TI1 (MH)
EPA3 (MC, MD)
2052H
2050H
††
PTS service is not useful for multiplexed interrupts because the PTS cannot readily
determine the source of these interrupts.
†
On the 8XC196MC device bits 10–12 are reserved. For compatibility with future devices, write zeros
to these bits.
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REGISTERS
PTSSRV
Address:
Reset State:
0006H
0000H
PTSSRV
The PTS service (PTSSRV) register is used by the hardware to indicate that the final PTS interrupt has
been serviced by the PTS routine. When PTSCOUNT reaches zero, hardware clears the corre-
sponding PTSSEL bit and sets the PTSSRV bit, which requests the end-of-PTS interrupt. When the
end-of-PTS interrupt is called, hardware clears the PTSSRV bit. The PTSSEL bit must be set manually
to re-enable the PTS channel.
15
8
8XC196MC
8XC196MD
8XC196MH
—
EXTINT
EPA2
PI
—
—
—
COMP3
AD
EPA3
7
0
COMP2
COMP1
EPA1
COMP0
EPA0
OVRTM
15
8
—
7
EXTINT
EPA2
PI
EPA5
EPA1
COMP4
COMP0
EPA4
EPA0
COMP3
AD
EPA3
0
COMP2
COMP1
OVRTM
15
—
7
8
EXTINT
WG
SPI
RI1
RI0
TI1
AD
TI0
0
COMP3 COMP2 COMP1
EPA1
COMP0
EPA0
OVRTM
Bit
Number
Function
15
Reserved. This bit is undefined.
14:0†
A bit is set by hardware to request an end-of-PTS interrupt for the corresponding interrupt
through its standard interrupt vector.
The PTS interrupt vector locations are as follows:
Bit Mnemonic
EXTINT
PTS Vector
205CH
205AH
205AH
2058H
2058H
2056H
2056H
2054H
2054H
Bit Mnemonic
TI0 (MH)
PTS Vector
2050H
204EH
204EH
204CH
204CH
204AH
2048H
2046H
2044H
2042H
2040H
PI (MC, MD)††
WG (MH)
COMP2 (MC,MD)
COMP3 (MH)
EPA2 (MC, MD)
COMP2 (MH)
COMP1
EPA1
COMP0
EPA0
AD
OVRTM††
EPA5 (MD)
SPI (MH)††
COMP4 (MD)
RI1 (MH)
EPA4 (MD)
RI0 (MH)
COMP3 (MC, MD) 2052H
TI1 (MH)
EPA3 (MC, MD)
2052H
2050H
††
PTS service is not useful for multiplexed interrupts because the PTS cannot readily
determine the source of these interrupts.
†
On the 8XC196MC device bits 10–12 are reserved. These bits are undefined.
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PWM_COUNT
Address:
Reset State:
1FB6H
00H
PWM_COUNT
(read only)
The PWM count (PWM_COUNT) register provides the current value of the decremented period
counter.
7
0
PWM Count Value
Bit
Number
Function
7:0
PWM Count Value
This register contains the current value of the decremented period counter.
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REGISTERS
PWM_PERIOD
Address:
Reset State:
1FB4H
00H
PWM_PERIOD
The PWM period (PWM_PERIOD) register controls the period of the PWM outputs. It contains a value
that determines the number of state counts necessary for incrementing the PWM counter. The value
of PWM_PERIOD is loaded into the PWM period count register whenever the count equals zero.
7
0
PWM Period
Bit
Number
Function
7:0
PWM Period
This register controls the period of the PWM outputs. The value of PWM_PERIOD is
loaded into the PWM period count register whenever the count equals zero.
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PWMx_CONTROL
Address:
Reset State:
1FB0H, 1FB2H
00H
PWMx_CONTROL
x = 0–1
The PWM control (PWMx_CONTROL) register determines the duty cycle of the PWM x channel. A
zero loaded into this register causes the PWM to output a low continuously (0% duty cycle). An FFH in
this register causes the PWM to have its maximum duty cycle (99.6% duty cycle).
7
0
PWM Duty Cycle
Bit
Number
Function
7:0
PWM Duty Cycle
This register controls the PWM duty cycle. A zero loaded into this register causes the
PWM to output a low continuously (0% duty cycle). An FFH in this register causes the
PWM to have its maximum duty cycle (99.6% duty cycle).
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REGISTERS
SBUFx_RX
Address: 1F80H, 1F88H
SBUFx_RX
x = 0–1 (8XC196MH)
Reset State:
00H
The serial port receive buffer x (SBUFx_RX) register contains data received from serial port x. The
serial port receiver is buffered and can begin receiving a second data byte before the first byte is read.
Data is held in the receive shift register until the last data bit is received, then the data byte is loaded
into SBUFx_RX. If data in the shift register is loaded into SBUFx_RX before the previous byte is read,
the overflow error bit is set (SPx_STATUS.2). The data in SBUFx_RX will always be the last byte
received, never a combination of the last two bytes.
7
0
8XC196MH
Data Received
Bit
Number
Function
7:0
Data Received
This register contains the last byte of data received from the serial port.
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SBUFx_TX
Address:
Reset State:
1F82H, 1F8AH
00H
SBUFx_TX
x = 0–1 (8XC196MH)
The serial port transmit buffer x (SBUFx_TX) register contains data that is ready for transmission. In
modes 1, 2, and 3, writing to SBUFx_TX starts a transmission. In mode 0, writing to SBUFx_TX starts
a transmission only if the receiver is disabled (SPx_CON.3=0).
7
0
8XC196MH
Data to Transmit
Bit
Number
Function
7:0
Data to Transmit
This register contains a byte of data to be transmitted by the serial port.
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REGISTERS
SP
Address:
Reset State:
18H
XXXXH
SP
The system’s stack pointer (SP) can point anywhere in internal or external memory; it must be word
aligned and must always be initialized before use. The stack pointer is decremented before a PUSH
and incremented after a POP, so the stack pointer should be initialized to two bytes (in 64-Kbyte
mode) or four bytes (in 1-Mbyte mode) above the highest stack location. If stack operations are not
being performed, locations 18H and 19H may be used as standard registers.
15
0
Stack Pointer
Bit
Number
Function
15:0
Stack Pointer
This register makes up the system’s stack pointer.
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SPx_BAUD
Address:
Reset State:
1F84H, 1F8CH
0000H
SPx_BAUD
x = 0–1 (8XC196MH)
The serial port baud rate x (SPx_BAUD) register selects the serial port x baud rate and clock source.
The most-significant bit selects the clock source. The lower 15 bits represent BAUD_VALUE, an
unsigned integer that determines the baud rate.
The maximum BAUD_VALUE is 32,767 (7FFFH). In asynchronous modes 1, 2, and 3, the minimum
BAUD_VALUE is 0000H when using XTAL1 and 0001H when using BCLKx. In synchronous mode 0,
the minimum BAUD_VALUE is 0001H for transmissions and 0002H for receptions. In synchronous
mode 4, the minimum BAUD_VALUE is 0001H for both transmissions and receptions.
15
8
0
8XC196MH
CLKSRC
BV14
BV6
BV13
BV5
BV12
BV4
BV11
BV3
BV10
BV2
BV9
BV1
BV8
BV0
7
BV7
Bit
Number
Bit
Mnemonic
Function
15
CLKSRC
Serial Port Clock Source
This bit determines whether the serial port is clocked from an internal or an
external source.
0 = signal on the T1CLK pin (external source)
1 = input frequency on the XTAL1 pin (internal source)
14:0
BV14:0
These bits constitute the BAUD_VALUE.
Use the following equations to determine the BAUD_VALUE for a given
baud rate.
Synchronous mode 0:†
FXTAL1
BCLKx
-------------------------------------
Baud Rate × 2
---------------------------
BAUD_VALUE =
– 1
or
Baud Rate
Asynchronous modes 1, 2, and 3:
FXTAL1
BCLKx
-------------------------------------
----------------------------------------
BAUD_VALUE =
– 1 or
Baud Rate × 8
Baud Rate × 16
Synchronous mode 4 (SCLKx# output):
FXTAL1
-------------------------------------
BAUD_VALUE =
– 1
Baud Rate × 4
†
For mode 0 receptions, the BAUD_VALUE must be 0002H or greater.
Otherwise, the resulting data in the receive shift register will be incorrect.
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REGISTERS
SPx_CON
Address:
Reset State:
1F83H, 1F8BH
00H
SPx_CON
x = 0–1 (8XC196MH)
The serial port control (SPx_CON) register selects the communications mode and enables or disables
the receiver, parity checking, and nine-bit data transmission.
7
0
8XC196MH
M2
DIR
PAR
TB8
REN
PEN
M1
M0
Bit
Number
Bit
Mnemonic
Function
7
6
M2
See description for bits 0 and 1.
Synchronous Clock Direction
DIR
PAR
TB8
This bit determines the direction of the clock during synchronous mode.
0 = output
1 = input
5
4
Parity Selection Bit
This bit selects even or odd parity.
0 = even parity
1 = odd parity
Transmit Ninth Data Bit
This is the ninth data bit that will be transmitted in mode 2 or 3. This bit is
cleared after each transmission, so it must be set before SBUFx_TX is
written. When parity is enabled (SPx_CON.2 = 1), this bit takes on the
even parity value.
3
REN
Receive Enable
Setting this bit enables receptions. When this bit is set, a falling edge on
the RXDx pin starts a reception in mode 1, 2, or 3. In mode 0, this bit must
be clear for transmission to begin and must be set for reception to begin.
Clearing this bit stops a reception in progress and inhibits further
receptions. To avoid a partial or undesired reception, clear this bit before
clearing the RI flag in SPx_STATUS. This can be handled in an interrupt
environment by using software flags or in straight-line code by using the
interrupt pending register to signal the completion of a reception.
2
PEN
M1:0
Parity Enable
In modes 1 and 3, setting this bit enables the parity function. This bit must
be cleared if mode 2 is used. When this bit is set, TB8 takes the parity
value on transmissions and SPx_STATUS.7 becomes the receive parity
error bit.
1:0
Mode Selection
These bits along with bit 7 select the communications mode.
M2
0
X
M1
0
0
M0
0
1
synchronous mode 0
mode 1
X
1
0
mode 2
X
1
1
mode 3
1
0
0
synchronous mode 4
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SPx_STATUS
Address:
Reset State:
1F81H, 1F89H
00H
SPx_STATUS
x = 0–1 (8XC196MH)
The serial port status (SPx_STATUS) register contains bits that indicate the status of serial port x.
7
0
8XC196MH RPE/RB8
RI
TI
FE
TXE
OE
—
—
Bit
Number
Bit
Mnemonic
Function
7
RPE/RB8
Received Parity Error/Received Bit 8
RPE is set if parity is disabled (SPx_CON.2 = 0) and the ninth data bit
received is high.
RB8 is set if parity is enabled (SPx_CON.2 = 1) and a parity error occurred.
Reading SPx_STATUS clears this bit.
6
RI
Receive Interrupt
This bit is set when the last data bit is sampled. Reading SPx_STATUS
clears this bit.
5
TI
Transmit Interrupt
This bit is set at the beginning of the stop bit transmission. Reading
SPx_STATUS clears this bit.
4
FE
TXE
OE
—
Framing Error
This bit is set if a stop bit is not found within the appropriate period of time.
Reading SPx_STATUS clears this bit.
3
SBUFx_TX Empty
This bit is set if the transmit buffer is empty and ready to accept up to two
bytes. It is cleared when a byte is written to SBUFx_TX.
2
Overrun Error
This bit is set if data in the receive shift register is loaded into SBUFx_RX
before the previous bit is read. Reading SPx_STATUS clears this bit.
1:0
Reserved; for compatibility with future devices, write zeros to these bits.
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REGISTERS
T1CONTROL
Address:
Reset State:
1F78H
00H
T1CONTROL
The timer 1 control (T1CONTROL) register determines the clock source, counting direction, and count
rate for timer 1.
7
0
CE
UD
M2
M1
M0
P2
P1
P0
Bit
Number
Bit
Mnemonic
Function
7
CE
Counter Enable
This bit enables or disables the timer. From reset, the timers are
disabled and not free running.
0 = disables timer
1 = enables timer
6
UD
Up/Down
This bit determines the timer counting direction, in selected modes (see
mode bits, M2:0).
0 = count down
1 = count up
5:3
M2:0
EPA Clock Direction Mode Bits
These bits determine the timer clocking source and direction control
source.
M2
M1
M0
Clock Source Direction Source
0
X
0
0
1
0
0
1
1
1
0
1
0
1
1
F
XTAL1/4
T1CLK pin†
XTAL1/4
T1CLK pin†
UD bit (T1CONTROL.6)
UD bit (T1CONTROL.6)
T1DIR pin
F
T1DIR pin
quadrature clocking using T1CLK and T1DIR
†
If an external clock is selected, the timer counts on both the rising
and falling edges of the clock.
2:0
P2:0
EPA Clock Prescaler Bits
These bits determine the clock prescaler value.
P2
P1
P0
Prescaler Divisor
Resolution†
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
divide by 1 (disabled)
divide by 2
divide by 4
divide by 8
divide by 16
divide by 32
divide by 64
enable T1RELOAD
250 ns
500 ns
1 µs
2 µs
4 µs
8 µs
16 µs
—
†
At 16 MHz. Use the formula on page 11-6 to calculate the resolution
at other frequencies.
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T1RELOAD
Address:
Reset State:
1F72H
XXXXH
T1RELOAD
The timer 1 reload (T1RELOAD) register contains a reinitialization value for timer 1. The value of
T1RELOAD is loaded into TIMER1 when timer 1 overflows or underflows and both quadrature
clocking and the reload function are enabled (i.e., T1CONTROL.5:0 = 1).
15
0
Timer 1 Reload Value
Bit
Number
Function
15:0
Timer 1 Reload Value
Write the timer 1 reinitialization value to this register.
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REGISTERS
T2CONTROL
Address:
Reset State:
1F7CH
00H
T2CONTROL
The timer 2 control (T2CONTROL) register determines the clock source, counting direction, and count
rate for timer 2.
7
0
CE
UD
M2
M1
M0
P2
P1
P0
Bit
Number
Bit
Mnemonic
Function
7
CE
Counter Enable
This bit enables or disables the timer. From reset, the timers are
disabled and not free running.
0 = disables timer
1 = enables timer
6
UD
Up/Down
This bit determines the timer counting direction, in selected modes (see
mode bits, M2:0).
0 = count down
1 = count up
5:3
M2:0
EPA Clock Direction Mode Bits
These bits determine the timer clocking source and direction source.
M2
M1
M0
Clock Source
XTAL1/4
reserved
reserved
reserved
timer 1 overflow
timer 1 overflow
reserved
Direction Source
0
X
0
0
1
1
1
0
0
1
1
0
1
1
0
1
0
1
0
0
1
F
UD bit (T2CONTROL.6)
—
—
—
UD bit (T2CONTROL.6)
same as timer 1
—
2:0
P2:0
EPA Clock Prescaler Bits
These bits determine the clock prescaler value.
P2
P1
P0
Prescaler
Resolution†
0
0
0
0
1
1
1
1
†
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
divide by 1 (disabled)
divide by 2
divide by 4
250 ns
500 ns
1 µs
2 µs
4 µs
8 µs
16 µs
—
divide by 8
divide by 16
divide by 32
divide by 64
reserved
Resolution at 16 MHz. Use the formula on page 11-6 to calculate the
resolution at other frequencies.
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TIMERx
Address:
Reset State:
1F7AH,
1F7EH
0000H
TIMERx
x = 1–2
This register contains the value of timer x. This register can be written, allowing timer x to be initialized
to a value other than zero.
15
0
Timer Value
Bit
Number
Function
15:0
Timer Value
Read the current timer x value from this register or write a new timer x value to this
register.
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REGISTERS
USFR
Address:
Reset State (MC, MD):
Reset State (MH):
1FF6H
02H
XXH
USFR
The unerasable PROM (USFR) register contains two bits that disable external fetches of data and
instructions and another that detects a failed oscillator. These bits can be programmed, but cannot be
erased.
WARNING: These bits can be programmed, but can never be erased. Programming these bits makes
dynamic failure analysis impossible. For this reason, devices with programmed UPROM bits cannot
be returned to Intel for failure analysis.
7
0
—
—
—
—
DEI
DED
—
—
Bit
Number
Bit
Mnemonic
Function
7:4
—
Reserved; for compatibility with future devices, write zeros to these bits.
Disable External Instruction Fetch
3
DEI
DED
—
Setting this bit prevents the bus controller from executing external
instruction fetches. Any attempt to load an external address initiates a
reset.
2
Disable External Data Fetch
Setting this bit prevents the bus controller from executing external data
reads and writes. Any attempt to access data through the bus controller
initiates a reset.
1:0
Reserved; for compatibility with future devices, write zero to these bits.
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WATCHDOG
Address:
Reset State:
0AH
XXH
WATCHDOG
Unless it is cleared every 64K state times, the watchdog timer resets the device. To clear the
watchdog timer, send “1EH” followed immediately by “E1H” to location 0AH. Clearing this register the
first time enables the watchdog with an initial value of 0000H, which is incremented once every state
time. After it is enabled, the watchdog can be disabled only by a reset.
The WDE bit (bit 3) of CCR1 controls whether the watchdog is enabled immediately or is disabled until
the first time it is cleared. Clearing WDE activates the watchdog. Setting WDE makes the watchdog
timer inactive, but you can activate it by clearing the watchdog register. Once the watchdog is
activated, only a reset can disable it.
7
0
Watchdog Timer Value
Bit
Number
Function
7:0
Watchdog Timer Value
This register contains the 8 most-significant bits of the current value of the watchdog
timer.
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REGISTERS
WG_COMPx
Address: 1FC2H,1FC4H,1FC6H
WG_COMPx
x = 1–3
Reset State:
0000H
The phase compare (WG_COMPx) register controls the duty cycle of each phase. Write a value to
each phase compare register to specify the length of time that the associated outputs will remain
asserted.
Changing the WG_RELOAD value changes both the carrier period and the duty cycle because the
outputs remain asserted for a constant length of time, while the counter takes longer to cycle. To
change the carrier period without changing the duty cycle, you must proportionally change both
WG_RELOAD and WG_COMPx at the same time, immediately after the interrupt.
15
0
Compare
Bit
Number
Function
15:0
Compare
These bits determine the length of time that the associated outputs are asserted.
Use the following formulas to calculate output assertion time and duty cycle.
multiplier × WG_COMPx
----------------------------------------------------------------
TOUTPUT
=
FXTAL1
WG_COMPx
-------------------------------------
Duty Cycle =
× 100%
WG_RELOAD
where:
TOUTPUT
=
=
=
=
=
total time output is asserted, in µs
FXTAL1
input frequency on XTAL1 pin, in MHz
multiplier
WG_RELOAD
WG_COMPx
4 for center-aligned modes; 2 for edge-aligned modes
16-bit WG_RELOAD value ≥ WG_COMPx
16-bit WG_COMPx value ≤ WG_RELOAD
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WG_CONTROL
Address:
Reset State (MC, MD):
Reset State (MH):
1FCCH
00C0H
8000H
WG_CONTROL
The waveform generator control (WG_CONTROL) register controls the operating mode, dead time,
and count direction, and enables and disables the counter.
15
8
0
—
M2
M1
M0
CS
EC
DT9
DT1
DT8
DT0
7
DT7
DT6
DT5
DT4
DT3
DT2
Bit
Bit
Mnemonic
Function
Number
15
14:12
—
Reserved; for compatibility with future devices, write zero to this bit.
M2:0
Operating Mode
This field controls the waveform generator’s operating mode:
M2
M1
M0
Mode
0
0
0
0
1
0
0
1
1
1
0
1
0
1
1
0
1
2
3
4
center-aligned; update registers once
center-aligned; update registers twice
edge-aligned; update registers once
edge-aligned; update registers twice
(8XC196MH only) edge-aligned; update
WG_COMPx and WG_COUNTER only when
WG_COUNTER = WG_RELOAD
11
CS
Counter Status
This read-only bit indicates whether the counter is counting up or
counting down.
0 = down counting
1 = up counting
10
EC
Enable Counter
This bit starts and stops the counter.
0 = disable (stop) counter
1 = enable (start) counter
9:0
DT9:0
Dead-time
This field specifies the dead-time for all three phases. Use the following
formula to calculate the appropriate DT_VALUE.
TDEAD × FXTAL1
------------------------------------------
DT_VALUE =
2
where:
TDEAD = dead-time, in µs
XTAL1 = input frequency on XTAL1 pin, in MHz
F
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REGISTERS
WG_COUNTER
Address:
Reset State (MC, MD):
Reset State (MH):
1FCAH
XXXXH
0000H
WG_COUNTER
You can read the waveform generator counter (WG_COUNTER) register to determine the current
counter value.
15
0
Counter Value
Bit
Number
Function
15:0
Counter Value
This register reflects the current counter value.
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WG_OUTPUT (Port 6)
Address:
Reset State:
1FC0H
0000H
WG_OUTPUT (Port 6)
The port 6 output configuration (WG_OUTPUT) register controls port 6 functions. If you are using port
6 for general-purpose outputs, write C0H (for active-high outputs) or 00H (for active-low outputs) to
the high byte of WG_OUTPUT and write the desired pin values to the low byte.
15
8
OP1
D7
OP0
D6
—
M7
D4
M6
D3
M5:4
D2
M3:2
D1
M1:0
D0
7
0
D5
Bit
Number
Bit
Mnemonic
Function
15:14
OP1:0
Output Polarity
These bits select the output polarity of the port 6 pins.
0 = active-low outputs
1 = active-high outputs
13
—
Reserved; for compatibility with future devices, write zero to this bit.
Mode
12:8
M7:0
These bits select either the peripheral function or general-purpose
output function of the port 6 pins. Clear these bits for general-purpose
output.
7:0
D7:0
Data
In general-purpose output mode, these bits hold the values to be driven
out on the pins. Write the desired values to these bits (bits 7:0
correspond to pins P6.7:0).
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REGISTERS
WG_OUTPUT (Waveform Generator)
Address:
Reset State:
1FC0H
0000H
WG_OUTPUT (Waveform Generator)
The waveform generator output configuration (WG_OUTPUT) register controls the configuration of
the waveform generator and PWM module pins. Both the waveform generator and the PWM module
share pins with port 6. Having these control bits in a single register enables you to configure all port 6
pins with a single write to WG_OUTPUT.
15
8
OP1
P7
OP0
P6
SYNC
PH3.1
PE7
PE6
PH3.2
PH2.0
PH2.2
PH1.1
PH1.2
PH1.0
7
0
PH3.0
PH2.1
Bit
Number
Bit
Mnemonic
Function
15
OP1
Output Polarity
Selects the output polarity for negative-phase outputs WG1#, WG2#,
and WG3#.
0 = active-low outputs
1 = active-high outputs
14
13
OP0
Output Polarity
Selects the output polarity for positive-phase outputs WG1, WG2, and
WG3.
0 = active-low outputs
1 = active-high outputs
SYNC
Synchronize
Selects whether updating the WG_OUTPUT register is synchronized
with another event or occurs immediately after you change it.
0 = update WG_OUTPUT immediately
1 = synchronize WG_OUTPUT update with an event
To ensure that the outputs are in the desired states when the waveform
generator starts, you should initially clear this bit, then set it later if you
want subsequent WG_OUTPUT updates to be synchronized with an
event. (Table 9-4 on page C-8 lists the events that update WG_OUTPUT
in each mode.)
12
11
PE7
PE6
P6.7/PWM1 Function
Selects the port function or the PWM output function of P6.7/PWM1.
0 = P6.7
1 = PWM1
P6.6/PWM0 Function
Selects the port function or the PWM output function of P6.6/PWM0.
0 = P6.6
1 = PWM0
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WG_OUTPUT (Waveform Generator)
Address:
Reset State:
1FC0H
0000H
WG_OUTPUT (Waveform Generator) (Continued)
The waveform generator output configuration (WG_OUTPUT) register controls the configuration of
the waveform generator and PWM module pins. Both the waveform generator and the PWM module
share pins with port 6. Having these control bits in a single register enables you to configure all port 6
pins with a single write to WG_OUTPUT.
15
8
OP1
P7
OP0
P6
SYNC
PH3.1
PE7
PE6
PH3.2
PH2.0
PH2.2
PH1.1
PH1.2
PH1.0
7
0
PH3.0
PH2.1
Bit
Number
Bit
Mnemonic
Function
10
PH3.2
Phase 3 Function
Selects either the port function or the waveform generator output
function for pins P6.4/WG3# and P6.5/WG3.
0 = P6.4, P6.5
1 = WG3#, WG3
9
8
PH2.2
PH1.2
Phase 2 Function
Selects either the port function or the waveform generator output
function for pins P6.2/WG2# and P6.3/WG2.
0 = P6.2, P6.3
1 = WG2#, WG2
Phase 1 Function
Selects either the port function or the waveform generator output
function for pins P6.0/WG1# and P6.1/WG1.
0 = P6.0, P6.1
1 = WG1#, WG1
7
P7
P6.7/PWM1 Value
Write the desired P6.7/PWM1 value to this bit.
6
P6
P6.6/PWM0 Value
Write the desired P6.6/PWM0 value to this bit.
5:4
PH3.1:0
P6.4/WG3#, P6.5/WG3 Value
Write the desired output values to these bits. See Table C-11 on page
C-65.
3:2
1:0
PH2.1:0
PH1.1:0
P6.2/WG2#, P6.3/WG2 Values
Write the desired output values to these bits. See Table C-11 on page
C-65.
P6.0/WG1#, P6.1/WG1 Values
Write the desired output values to these bits. See Table C-11 on page
C-65.
C-64
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REGISTERS
WG_OUTPUT (Waveform Generator)
,
Table C-11. Output Configuration
Output Values Output Polarities
PHx.2 PHx.1 PHx.0
WGx
WGx#
WGx
WGx#
1
1
0
0
0
1
Low
Low
Always Low
Always Low
Low
WG_EVEN#
Always Low
1
1
1
1
0
1
WG_ODD
Low
Always Low
WG_ODD WG_EVEN
NOTE: This table assumes active-high outputs (OP1=OP0=1).
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WG_PROTECT
Address:
Reset State (MC, MD)
Reset State (MH):
1FCEH
F0H
WG_PROTECT
E0H
The waveform protection (WG_PROTECT) register enables and disables the outputs and the
protection circuitry. It also selects either level-sensitive or edge-triggered EXTINT interrupts, and
selects which level or edge will generate an EXTINT interrupt request.
7
0
0
8XC196MC, MD
8XC196MH
—
—
—
—
—
—
—
ES
ES
IT
IT
DP
DP
EO
EO
7
PT
Bit
Number
Bit
Mnemonic
Function
7:5
—
Reserved; for compatibility with future devices, write zeros to these bits.
6†
PT
Protection Type
This bit selects the method used for disabling the outputs.
0 = inactive states
1 = weak pull-ups
3:2
ES
IT
Enable Sampling and Interrupt Type
The ES bit selects whether the protection circuitry samples the EXTINT
signal level or detects a signal transition (edge), while the IT bit controls
which value of the edge or level triggers an interrupt request. The
possible combinations are as follows.
ES
IT
Event
0
0
1
1
0
1
0
1
falling edge
rising edge
low level
high level
1
DP
EO
Disable Protection
This bit enables and disables the protection circuitry.
0 = enable protection
1 = disable protection
0
Enable Outputs
This bit enables and disables the outputs.
0 = disable outputs
1 = enable outputs
†
On the 8XC196MC, MD devices, this bit is reserved. For compatibility with future devices, always
write as zero.
C-66
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REGISTERS
WG_RELOAD
Address:
Reset State:
1FC8H
0000H
WG_RELOAD
The waveform generator reload (WG_RELOAD) register and the phase compare registers
(WG_COMPx) control the carrier period and duty cycle. Write a value to the reload register to
establish the carrier period.
Changing the WG_RELOAD value changes both the carrier period and the duty cycle because the
outputs remain asserted for a constant length of time, while the counter takes longer to cycle. To
change the carrier period without changing the duty cycle, you must proportionally change both
WG_RELOAD and WG_COMPx at the same time, immediately after the interrupt.
15
0
Reload
Bit
Number
Function
15:0
Reload
This register determines the carrier period.
Use the following formulas to calculate carrier period and duty cycle.
multiplier × WG_RELOAD
--------------------------------------------------------------------
TCARRIER
=
FXTAL1
WG_COMPx
-------------------------------------
Duty Cycle =
× 100%
WG_RELOAD
where:
TCARRIER
=
=
=
=
=
carrier period, in µs
FXTAL1
input frequency on XTAL1 pin, in MHz
4 for center-aligned modes; 2 for edge-aligned modes
16-bit WG_RELOAD value ≥ WG_COMPx
16-bit WG_COMPx value ≤ WG_RELOAD
multiplier
WG_RELOAD
WG_COMPx
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WSR
Address:
Reset State:
0014H
00H
WSR
The window selection register (WSR) maps sections of RAM into the top of the lower register file, in
32-, 64-, or 128-byte increments. PUSHA saves this register on the stack and POPA restores it.
7
0
—
W6
W5
W4
W3
W2
W1
W0
Bit
Bit
Function
Number Mnemonic
7
—
Reserved; for compatibility with future devices, write zero to this bit.
Window Selection
6:0
W6:0
These bits specify the window size and number. Table C-12 shows the WSR
settings and direct addresses for windowable SFRs.
Table C-12. WSR Settings and Direct Addresses for Windowable SFRs
32-byte Windows
(00E0–00FFH)
64-byte Windows
(00C0–00FFH)
128-byte Windows
(0080–00FFH)
Memory
Location
Register Mnemonic
Direct
WSR
Direct
WSR
Direct
WSR
Address
Address
Address
AD_COMMAND
AD_RESULT
1FACH
1FAAH
1FAEH
1FAFH
1F58H
1F5CH
1F60H
1F64H
1F68H
1F6CH
1F5AH
1F5EH
1F62H
1F66H
1F6AH
1F6EH
1F40H
1F44H
7DH
7DH
7DH
7DH
7AH
7AH
7BH
7BH
7BH
7BH
7AH
7AH
7BH
7BH
7BH
7BH
7AH
7AH
00ECH
00EAH
00EEH
00EFH
00F8H
00FCH
00E0H
00E4H
00E8H
00ECH
00FAH
00FEH
00E2H
00E6H
00EAH
00EEH
00E0H
00E4H
3EH
3EH
3EH
3EH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
00ECH
00EAH
00EEH
00EFH
00D8H
00DCH
00E0H
00E4H
00E8H
00ECH
00DAH
00DEH
00E2H
00E6H
00EAH
00EEH
00C0H
00C4H
1FH
1FH
1FH
1FH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
00ACH
00AAH
00AEH
00AFH
00D8H
00DCH
00E0H
00E4H
00E8H
00ECH
00DAH
00DEH
00E2H
00E6H
00EAH
00EEH
00C0H
00C4H
AD_TEST
AD_TIME
COMP0_CON
COMP1_CON
COMP2_CON
COMP3_CON
COMP4_CON (MD)
COMP5_CON (MD)
COMP0_TIME†
COMP1_TIME†
COMP2_TIME†
COMP3_TIME†
COMP4_TIME† (MD)
COMP5_TIME† (MD)
EPA0_CON
EPA1_CON†
† Must be addressed as a word.
C-68
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REGISTERS
WSR
Table C-12. WSR Settings and Direct Addresses for Windowable SFRs (Continued)
32-byte Windows
(00E0–00FFH)
64-byte Windows
(00C0–00FFH)
128-byte Windows
(0080–00FFH)
Memory
Location
Register Mnemonic
Direct
WSR
Direct
WSR
Direct
WSR
Address
Address
Address
EPA2_CON (MC, MD)
EPA3_CON† (MC, MD)
EPA4_CON (MD)
EPA5_CON (MD)
EPA0_TIME†
1F48H
1F4CH
1F50H
1F54H
1F42H
1F46H
1F4AH
1F4EH
1F52H
1F56H
1FBAH
1FB8H
1FA0H
1F9AH
1FD2H
1FD3H
1F98H
1FD0H
1FD1H
1FA8H
1FDAH
1FA8H
1F9EH
1FD6H
1FD7H
1F9CH
1FD4H
1FD5H
1FBCH
1FBEH
1FB6H
1FB4H
7AH
7AH
7AH
7AH
7AH
7AH
7AH
7AH
7AH
7AH
7DH
7DH
7DH
7CH
7EH
7EH
7CH
7EH
7EH
7DH
7EH
7DH
7CH
7EH
7EH
7CH
7EH
7EH
7DH
7DH
7DH
7DH
00E8H
00ECH
00F0H
00F4H
00E2H
00E6H
00EAH
00EEH
00F2H
00F6H
00FAH
00FBH
00E0H
00FAH
00F2H
00F3H
00F8H
00F0H
00F1H
00E8H
00FAH
00E8H
00FEH
00F6H
00F7H
00FCH
00F4H
00F5H
00FCH
00FEH
00F6H
00F4H
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3DH
3EH
3EH
3EH
3EH
3FH
3FH
3EH
3FH
3FH
3EH
3FH
3EH
3EH
3FH
3FH
3EH
3FH
3FH
3EH
3EH
3EH
3EH
00C8H
00CCH
00D0H
00D4H
00C2H
00C6H
00CAH
00CEH
00D2H
00D6H
00FAH
00F8H
00E0H
00DAH
00D2H
00D3H
00D8H
00D0H
00D1H
00E8H
00DAH
00E8H
00DEH
00D6H
00D7H
00DCH
00D4H
00D5H
00FCH
00FEH
00F6H
00F4H
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1EH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
00C8H
00CCH
00D0H
00D4H
00C2H
00C6H
00CAH
00CEH
00D2H
00D6H
00BAH
00B8H
00A0H
009AH
00D2H
00D3H
0098H
00D0H
00D1H
00A8H
00DAH
00A8H
009EH
00D6H
00D7H
009CH
00D4H
00D5H
00BCH
00BEH
00B6H
00B4H
EPA1_TIME†
EPA2_TIME† (MC, MD)
EPA3_TIME† (MC, MD)
EPA4_TIME† (MD)
EPA5_TIME† (MD)
FREQ_CNT (MD)
FREQ_GEN (MD)
GEN_CON (MH)
P1_DIR (MH)
P2_DIR
P7_DIR (MD)
P1_MODE (MH)
P2_MODE
P7_MODE (MD)
P0_PIN (MC, MD)
P0_PIN (MH)
P1_PIN (MC)
P1_PIN (MH)
P2_PIN
P7_PIN (MD)
P1_REG (MH)
P2_REG
P7_REG (MD)
PI_MASK
PI_PEND
PWM_COUNT
PWM_PERIOD
† Must be addressed as a word.
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WSR
Table C-12. WSR Settings and Direct Addresses for Windowable SFRs (Continued)
32-byte Windows
(00E0–00FFH)
64-byte Windows
(00C0–00FFH)
128-byte Windows
(0080–00FFH)
Memory
Location
Register Mnemonic
Direct
WSR
Direct
WSR
Direct
WSR
Address
Address
Address
PWM0_CONTROL
PWM1_CONTROL
SBUF0_RX (MH)
SBUF1_RX (MH)
SBUF0_TX (MH)
SBUF1_TX (MH)
SP0_BAUD (MH)
SP1_BAUD (MH)
SP0_CON (MH)
SP1_CON (MH)
SP0_STATUS (MH)
SP1_STATUS (MH)
T1CONTROL
1FB0H
1FB2H
1F80H
1F88H
1F82H
1F8AH
1F84H
1F8CH
1F83H
1F8BH
1F81H
1F89H
1F78H
1F72H
1F7CH
1F7AH
1F7EH
1FC2H
1FC4H
1FC6H
1FCCH
1FCAH
1FC0H
1FCEH
1FC8H
7DH
7DH
7CH
7CH
7CH
7CH
7CH
7CH
7CH
7CH
7CH
7CH
7BH
7BH
7BH
7BH
7BH
7EH
7EH
7EH
7EH
7EH
7EH
7EH
7EH
00F0H
00F2H
00E0H
00E8H
00E2H
00EAH
00E4H
00ECH
00E3H
00EBH
00E1H
00E9H
00F8H
00F2H
00FCH
00FAH
00FEH
00E2H
00E4H
00E6H
00ECH
00EAH
00E0H
00EEH
00E8H
3EH
3EH
3EH
3EH
3EH
3EH
3EH
3EH
3EH
3EH
3EH
3EH
3DH
3DH
3DH
3DH
3DH
3FH
3FH
3FH
3FH
3FH
3FH
3FH
3FH
00F0H
00F2H
00C0H
00C8H
00C2H
00CAH
00C4H
00CCH
00C3H
00CBH
00C1H
00C9H
00F8H
00F2H
00FCH
00FAH
00FEH
00C2H
00C4H
00C6H
00CCH
00CAH
00C0H
00CEH
00C8H
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1EH
1EH
1EH
1EH
1EH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
1FH
00B0H
00B2H
0080H
0088H
0082H
008AH
0084H
008CH
0083H
008BH
0081H
0089H
00F8H
00F2H
00FCH
00FAH
00FEH
00C2H
00C4H
00C6H
00CCH
00CAH
00C0H
00CEH
00C8H
T1RELOAD
T2CONTROL
TIMER1†
TIMER2†
WG_COMP1
WG_COMP2
WG_COMP3
WG_CONTROL
WG_COUNTER
WG_OUTPUT
WG_PROTECT
WG_RELOAD
† Must be addressed as a word.
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REGISTERS
ZERO_REG
Address:
Reset State:
00H
0000H
ZERO_REG
The two-byte zero register (ZERO_REG) is always equal to zero. It is useful as a fixed source of the
constant zero for comparisons and calculations.
15
0
Zero
Bit
Number
Function
15:0
Zero
This register is always equal to zero.
C-71
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Glossary
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GLOSSARY
This glossary defines acronyms, abbreviations, and terms that have special meaning in this man-
ual. (Chapter 1 discusses notational conventions and general terminology.)
absolute error
The maximum difference between corresponding
actual and ideal code transitions. Absolute error
accounts for all deviations of an actual A/D converter
from an ideal converter.
accumulator
A register or storage location that forms the result of
an arithmetic or logical operation.
actual characteristic
A graph of output code versus input voltage of an
actual A/D converter. An actual characteristic may
vary with temperature, supply voltage, and frequency
conditions.
A/D converter
ALU
Analog-to-digital converter.
Arithmetic-logic unit. The part of the RALU that
processes arithmetic and logical operations.
assert
The act of making a signal active (enabled). The
polarity (high or low) is defined by the signal name.
Active-low signals are designated by a pound symbol
(#) suffix; active-high signals have no suffix. To assert
RD# is to drive it low; to assert ALE is to drive it
high.
attenuation
bit
A decrease in amplitude; voltage decay.
A binary digit.
BIT
A single-bit operand that can take on the Boolean
values, “true” and “false.”
break-before-make
The property of a multiplexer which guarantees that a
previously selected channel is deselected before a
new channel is selected. (That is, break-before-make
ensures that the A/D converter will not short inputs
together.)
byte
Any 8-bit unit of data.
BYTE
An unsigned, 8-bit variable with values from 0
through 2 –1.
8
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CCBs
Chip configuration bytes. The chip configuration
registers (CCRs) are loaded with the contents of the
CCBs after a device reset, unless the device is
entering programming modes, in which case the
PCCBs are used.
CCRs
Chip configuration registers. Registers that specify
the environment in which the device will be
operating. The chip configuration registers are loaded
with the contents of the CCBs after a device reset
unless the device is entering programming modes, in
which case the PCCBs are used.
channel-to-channel matching error
The difference between corresponding code
transitions of actual characteristics taken from
different A/D converter channels under the same
temperature, voltage, and frequency conditions. This
error is caused by differences in DC input leakage and
on-channel resistance from one multiplexer channel
to another.
characteristic
clear
A graph of output code versus input voltage; the
transfer function of an A/D converter.
The “0” value of a bit or the act of giving it a “0”
value. See also set.
code
1) A set of instructions that perform a specific
function; a program.
2) The digital value output by the A/D converter.
code center
The voltage corresponding to the midpoint between
two adjacent code transitions on the A/D converter.
code transition
The point at which the A/D converter’s output code
changes from “Q” to “Q+1.” The input voltage corre-
sponding to a code transition is defined as the voltage
that is equally likely to produce either of two adjacent
codes.
code width
The voltage change corresponding to the difference
between two adjacent code transitions. Code width
deviations cause differential nonlinearity and nonlin-
earity errors.
crosstalk
See off-isolation.
DC input leakage
Leakage current from an analog input pin to ground.
Glossary-2
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GLOSSARY
deassert
The act of making a signal inactive (disabled). The
polarity (high or low) is defined by the signal name.
Active-low signals are designated by a pound symbol
(#) suffix; active-high signals have no suffix. To
deassert RD# is to drive it high; to deassert ALE is to
drive it low.
differential nonlinearity
The difference between the actual code width and the
ideal one-LSB code width of the terminal-based
characteristic of an A/D converter. It provides a
measure of how much the input voltage may have
changed in order to produce a one-count change in the
conversion result. Differential nonlinearity is a
measure of local code-width error; nonlinearity is a
measure of overall code-transition error.
doping
The process of introducing a periodic table Group III
or Group V element into a Group IV element (e.g.,
silicon). A Group III impurity (e.g., indium or
gallium) results in a p-type material. A Group V
impurity (e.g., arsenic or antimony) results in an n-
type material.
double-word
Any 32-bit unit of data.
DOUBLE-WORD
An unsigned, 32-bit variable with values from 0
through 2 –1.
32
EPA
Event processor array. An integrated peripheral that
provides high-speed input/output capability.
EPROM
ESD
Erasable, programmable read-only-memory.
Electrostatic discharge.
feedthrough
The attenuation from an input voltage on the selected
channel to the A/D output after the sample window
closes. The ability of the A/D converter to reject an
input on its selected channel after the sample window
closes.
FET
Field-effect transistor.
frequency generator
The 8XC196MD peripheral that generates outputs
with a fixed 50% duty cycle and a programmable
frequency. The frequency generator can be used for
infrared transmission.
Glossary-3
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full-scale error
The difference between the ideal and actual input
voltage corresponding to the final (full-scale) code
transition of an A/D converter.
hold latency
The time it takes the microcontroller to assert HLDA#
after an external device asserts HOLD#.
ideal characteristic
The characteristic of an ideal A/D converter. An ideal
characteristic is unique: its first code transition occurs
when the input voltage is 0.5 LSB, its full-scale (final)
code transition occurs when the input voltage is 1.5
LSB less than the full-scale reference, and its code
widths are all exactly 1.0 LSB. These properties result
in a conversion without zero-offset, full-scale, or
linearity errors. Quantizing error is the only error
seen in an ideal A/D converter.
input leakage
Current leakage from an input pin to power or ground.
input series resistance
The effective series resistance from an analog input
pin to the sample capacitor of an A/D converter.
integer
Any member of the set consisting of the positive and
negative whole numbers and zero.
15
INTEGER
A 16-bit, signed variable with values from –2
through +2 –1.
15
interrupt controller
The module responsible for handling interrupts that
are to be serviced by interrupt service routines that
you provide. Also called the programmable interrupt
controller (PIC).
interrupt latency
The total delay between the time that an interrupt is
generated (not acknowledged) and the time that the
device begins executing the interrupt service routine
or PTS routine.
interrupt service routine
interrupt vector
A software routine that you provide to service a
standard interrupt. See also PTS routine.
A location in special-purpose memory that holds the
starting address of an interrupt service routine.
ISR
See interrupt service routine.
linearity errors
LONG-INTEGER
See differential nonlinearity and nonlinearity.
31
A 32-bit, signed variable with values from –2
31
through +2 –1.
Glossary-4
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GLOSSARY
LSB
1) Least-significant bit of a byte or least-significant
byte of a word.
2) In an A/D converter, the reference voltage divided
n
by 2 , where n is the number of bits to be converted.
For a 10-bit converter with a reference voltage of 5.12
10
volts, one LSB is equal to 5.0 millivolts (5.12 ÷ 2 ).
maskable interrupts
All interrupts except unimplemented opcode,
software trap, and NMI. Maskable interrupts can be
disabled (masked) by the individual mask bits in the
interrupt mask registers, and their servicing can be
disabled by the global interrupt enable bit. Each
maskable interrupt can be assigned to the PTS for
processing.
monotonic
The property of successive approximation converters
which guarantees that increasing input voltages
produce adjacent codes of increasing value, and that
decreasing input voltages produce adjacent codes of
decreasing value. (In other words, a converter is
monotonic if every code change represents an input
voltage change in the same direction.) Large differ-
ential nonlinearity errors can cause the converter to
exhibit nonmonotonic behavior.
MSB
Most-significant bit of a byte or most-significant byte
of a word.
n-channel FET
n-type material
A field-effect transistor with an n-type conducting
path (channel).
Semiconductor material with introduced impurities
(doping) causing it to have an excess of negatively
charged carriers.
no missing codes
nonlinearity
An A/D converter has no missing codes if, for every
output code, there is a unique input voltage range
which produces that code only. Large differential
nonlinearity errors can cause the converter to miss
codes.
The maximum deviation of code transitions of the
terminal-based characteristic from the corre-
sponding code transitions of the ideal characteristic.
Glossary-5
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nonmaskable interrupts
Interrupts that cannot be masked (disabled) and
cannot be assigned to the PTS for processing. The
nonmaskable interrupts are unimplemented opcode,
software trap, and NMI.
nonvolatile memory
Read-only memory that retains its contents when
power is removed. Many MCS 96 microcontrollers
®
are available with either masked ROM, EPROM, or
OTPROM. Consult the Automotive Products or
Embedded Microcontrollers databook to determine
which type of memory is available for a specific
device.
npn transistor
off-isolation
OTPROM
A transistor consisting of one part p-type material and
two parts n-type material.
The ability of an A/D converter to reject (isolate) the
signal on a deselected (off) output.
One-time-programmable read-only memory. Similar
to EPROM, but it comes in an unwindowed package
and cannot be erased.
p-channel FET
p-type material
A field-effect transistor with a p-type conducting
path.
Semiconductor material with introduced impurities
(doping) causing it to have an excess of positively
charged carriers.
PC
Program counter.
PCCBs
Programming chip configuration bytes, which are
loaded into the chip configuration registers (CCRs)
when the device is entering programming modes;
otherwise, the CCBs are used.
PIC
Programmable interrupt controller. The module
responsible for handling interrupts that are to be
serviced by interrupt service routines that you
provide. Also called simply the interrupt controller.
prioritized interrupt
Any maskable interrupt or nonmaskable NMI. Two of
the nonmaskable interrupts (unimplemented opcode
and software trap) are not prioritized; they vector
directly to the interrupt service routine when
executed.
Glossary-6
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GLOSSARY
program memory
A partition of memory where instructions can be
stored for fetching and execution.
protected instruction
An instruction that prevents an interrupt from being
acknowledged until after the next instruction
executes. The protected instructions are DI, EI, DPTS,
EPTS, POPA, POPF, PUSHA, and PUSHF.
PSW
Processor status word. The high byte of the PSW is
the status byte, which contains one bit that globally
enables or disables servicing of all maskable
interrupts, one bit that enables or disables the PTS,
and six Boolean flags that reflect the state of the
current program. The low byte of the PSW is the
INT_MASK register. A push or pop instruction saves
or restores both bytes (PSW + INT_MASK).
PTS
Peripheral transaction server. The microcoded
hardware interrupt processor.
PTSCB
See PTS control block.
PTS control block
A block of data required for each PTS interrupt. The
microcode executes the proper PTS routine based on
the contents of the PTS control block.
PTS cycle
The microcoded response to a single PTS interrupt
request.
PTS interrupt
PTS mode
Any maskable interrupt that is assigned to the PTS for
interrupt processing.
A microcoded response that enables the PTS to
complete a specific task quickly. These tasks include
transferring a single byte or word, transferring a block
of bytes or words, managing multiple A/D conver-
sions, and generating PWM outputs.
PTS routine
PTS transfer
PTS vector
The entire microcoded response to multiple PTS
interrupt requests. The PTS routine is controlled by
the contents of the PTS control block.
The movement of a single byte or word from the
source memory location to the destination memory
location.
A location in special-purpose memory that holds the
starting address of a PTS control block.
Glossary-7
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PWM
Pulse-width modulated (outputs). The 8XC196Mx
devices have several options for producing PWM
outputs: the generic pulse-width modulator modules,
the waveform generator, and the EPA with or without
the PTS. The 8XC196MD also has a frequency
generator that produces PWM outputs.
quantizing error
An unavoidable A/D conversion error that results
simply from the conversion of a continuous voltage to
its integer digital representation. Quantizing error is
always ± 0.5 LSB and is the only error present in an
ideal A/D converter.
RALU
Register arithmetic-logic unit. A part of the CPU that
consists of the ALU, the PSW, the master PC, the
microcode engine, a loop counter, and six registers.
repeatability error
The difference between corresponding code
transitions from different actual characteristics taken
from the same converter on the same channel with the
same temperature, voltage, and frequency conditions.
The amount of repeatability error depends on the
comparator’s ability to resolve very similar voltages
and the extent to which random noise contributes to
the error.
reserved memory
resolution
A memory location that is reserved for factory use or
for future expansion. Do not use a reserved memory
location except to initialize it with FFH.
The number of input voltage levels that an A/D
converter can unambiguously distinguish between.
The number of useful bits of information that the
converter can return.
sample capacitor
sample delay
A small (2–3 pF) capacitor used in the A/D converter
circuitry to store the input voltage on the selected
input channel.
The time period between the time that A/D converter
receives the “start conversion” signal and the time
that the sample capacitor is connected to the selected
channel.
sample delay uncertainty
The variation in the sample delay.
Glossary-8
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GLOSSARY
sample time
The period of time that the sample window is open.
(That is, the length of time that the input channel is
actually connected to the sample capacitor.)
sample time uncertainty
sample window
The variation in the sample time.
The period of time that begins when the sample
capacitor is attached to a selected channel of an A/D
converter and ends when the sample capacitor is
disconnected from the selected channel.
sampled inputs
All input pins, with the exception of RESET#, are
sampled inputs. The input pin is sampled one state
time before the read buffer is enabled. Sampling
occurs during PH1 (while CLKOUT is low) and
resolves the value (high or low) of the pin before it is
presented to the internal bus. If the pin value changes
during the sample time, the new value may or may not
be recorded during the read.
RESET# is a level-sensitive input. EXTINT is
normally a sampled input; however, the powerdown
circuitry uses EXTINT as a level-sensitive input
during powerdown mode.
SAR
set
Successive approximation register. A component of
the A/D converter.
The “1” value of a bit or the act of giving it a “1”
value. See also clear.
SFR
Special-function register.
7
SHORT-INTEGER
An 8-bit, signed variable with values from –2
through +2 –1.
7
sign extension
A method for converting data to a larger format by
filling the upper bit positions with the value of the
sign. This conversion preserves the positive or
negative value of signed integers.
sink current
source current
SP
Current flowing into a device to ground. Always a
positive value.
Current flowing out of a device from VCC. Always a
negative value.
Stack pointer.
Glossary-9
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special interrupt
Any of the three nonmaskable interrupts (unimple-
mented opcode, software trap, or NMI).
special-purpose memory
A partition of memory used for storing the interrupt
vectors, PTS vectors, chip configuration bytes, and
several reserved locations.
standard interrupt
state time (or state)
Any maskable interrupt that is assigned to the
interrupt controller for processing by an interrupt
service routine.
The basic time unit of the device; the combined
period of the two internal timing signals, PH1 and
PH2. (The internal clock generator produces PH1 and
PH2 by halving the frequency of the signal on
XTAL1. The rising edges of the active-high PH1 and
PH2 signals generate CLKOUT, the output of the
internal clock generator.) Because the device can
operate at many frequencies, this manual defines time
requirements in terms of state times rather than in
specific units of time.
successive approximation
An A/D conversion method that uses a binary search
to arrive at the best digital representation of an analog
input.
temperature coefficient
temperature drift
Change in the stated variable for each degree
Centigrade of temperature change.
The change in a specification due to a change in
temperature. Temperature drift can be calculated by
using the temperature coefficient for the specification.
terminal-based characteristic
transfer function
An actual characteristic that has been translated and
scaled to remove zero-offset error and full-scale error.
A terminal-based characteristic resembles an actual
characteristic with zero-offset error and full-scale
error removed.
A graph of output code versus input voltage; the
characteristic of the A/D converter.
Glossary-10
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GLOSSARY
transfer function errors
Errors inherent in an analog-to-digital conversion
process: quantizing error, zero-offset error, full-scale
error, differential nonlinearity, and nonlinearity.
Errors that are hardware-dependent, rather than being
inherent in the process itself, include feedthrough,
repeatability, channel-to-channel matching, off-
isolation, and VCC rejection errors.
UART
CC rejection
Universal asynchronous receiver and transmitter. A
part of the serial I/O port.
V
The property of an A/D converter that causes it to
ignore (reject) changes in VCC so that the actual
characteristic is unaffected by those changes. The
effectiveness of VCC rejection is measured by the ratio
of the change in VCC to the change in the actual
characteristic.
wait state
Time spent waiting for an operation to take place.
Wait states are added to external bus cycles to allow a
slow memory device to respond to a request from the
microcontroller.
watchdog timer
An internal timer that resets the device if software
fails to respond before the timer overflows.
waveform generator
One of the 8XC196Mx peripherals that can be used to
produce pulse-width modulated (PWM) outputs. The
waveform generator is optimized for controlling 3-
phase AC induction motors, brushless DC motors,
and other devices requiring multiple PWM outputs.
WDT
word
See watchdog timer.
Any 16-bit unit of data.
WORD
An unsigned, 16-bit variable with values from 0
through 2 –1.
16
zero extension
A method for converting data to a larger format by
filling the upper bit positions with zeros.
zero-offset error
An ideal A/D converter’s first code transition occurs
when the input voltage is 0.5 LSB. Zero-offset error is
the difference between 0.5 LSB and the actual input
voltage that triggers an A/D converter’s first code
transition.
Glossary-11
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Index
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INDEX
#, defined, 1-3, A-1
16-bit data bus
read cycles, 15-14
timing diagram, 15-15
write cycles, 15-14
8-bit data bus
transfer function, 12-15–12-18
zero-offset adjustment, 12-3, 12-5
zero-offset error, 12-16
See also port 0
A/D result register (read), 12-9, C-7
A/D result register (write), 12-6, C-8
A/D scan mode‚ See PTS
A/D test register, 12-5, C-9
A/D time register, 12-7, C-10
AC timing
read cycles, 15-16
timing diagram, 15-17
write cycles, 15-16
specifications, 15-31–15-34
symbol explanations, 15-33
Accumulator, RALU, 2-5
ACH13:0, B-13
AD_COMMAND, C-68
AD_RESULT, 12-9, C-68
AD_TEST, C-68
AD_TIME, C-68
AD15:0, B-13
ADD instruction, A-2, A-7, A-41, A-42, A-47,
A-52
ADDB instruction, A-2, A-7, A-42, A-43, A-47,
A-52
A
A/D command register, 12-8, C-6
A/D converter, 2-11, 12-1–12-18
actual characteristic, 12-16
and port 0 reads, 12-13
and PTS, 5-32–5-37
block diagram, 12-1
calculating result, 12-9, 12-13
calculating series resistance, 12-10
characteristics, 12-15–12-18
conversion time, 12-6
determining status, 12-9
errors, 12-13–12-18
hardware considerations, 12-10–12-13
ideal characteristic, 12-15, 12-16
input circuit, suggested, 12-12
input protection devices, 12-12
interfacing with, 12-10–12-13
interpreting results, 12-9
interrupt, 12-8
minimizing input source resistance, 12-11
overview, 12-3–12-4
programming, 12-4–12-8
sample delay, 12-4
sample time, 12-6
sample window, 12-4
SFRs, 12-2
signals, 12-2
starting with PTS, 5-32–5-37
successive approximation
algorithm, 12-4
register (SAR), 12-4
terminal-based characteristic, 12-18
threshold-detection modes, 12-5
ADDC instruction, A-2, A-7, A-44, A-47, A-52
ADDCB instruction, A-2, A-8, A-44, A-47, A-52
Address space
map, 4-2
See also memory partitions
Address valid strobe mode
ALE/ADV# comparison, 15-27
example system, 15-28, 15-29
signals, 15-27
Address valid with write strobe mode
example system, 15-31
signals, 15-30
Address/data bus, 2-6
multiplexing, 15-10–15-17
Addressing modes, 3-5–3-6, A-6
ADV#, B-13
AINC#, 16-12, B-14
ALE, B-14
idle, powerdown, reset status, B-23, B-25
Analog outputs, generating, 10-10
Analog-to-digital converter‚ See A/D converter
Index-1
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AND instruction, A-2, A-8, A-41, A-42, A-48,
A-53
ANDB instruction, A-2, A-8, A-9, A-42, A-43,
A-48, A-53
standard, 15-22–15-24
write strobe, 15-25–15-26
Bus-control signals, 15-21
Bus-width modes
ANGND, 12-5, 13-1, B-14
ApBUILDER software, downloading, 1-10
Application notes, ordering, 1-6
Arithmetic instructions, A-47, A-48, A-52, A-53
Assert, defined, 1-3
16-bit data bus, 15-14
8-bit data bus, 15-16
dynamic data bus, 15-13
dynamic example, 15-24
BUSWIDTH, 16-25, 16-27, B-15
idle, powerdown, reset status, B-23, B-25
timing, 15-11
Auto programming mode, 16-25–16-28
algorithm, 16-28
circuit, 16-25–16-26
definitions, 15-13
memory map, 16-27
diagram, 15-12
PCCB, 16-27
requirements, 15-13
security key programming, 16-29
BYTE, defined, 3-2
B
C
Baud rate
Call instructions, A-50, A-55, A-56
Carry (C) flag, 3-4, A-4, A-5, A-11, A-18, A-19,
A-20, A-21, A-31
SIO port, 7-12–7-14
Baud-rate generator
SIO port, 7-12
BAUD_VALUE, 7-13
BCLK1:0, B-14
Cascading timers, 11-7
CCB fetch
and BHE#, 6-13
BCLKx, 7-2
and P5.5, 6-13
BHE#, B-14
and P5.6, 6-13
BIT, defined, 3-2
and READY, 6-13
Bit-test instructions, A-17
Block diagram
CCBs, 4-3, 13-8
security-lock bits, 16-29–16-30
CCBs, See also chip configuration bytes
CCR0, 14-2
A/D converter, 12-1
address/data bus, 6-15
clock circuitry, 2-7
CCRs, 13-8, 14-5
core and peripherals, 2-3
EPA, 11-2
frequency generator, 8-1
infrared remote control application, 8-5
I/O ports, 6-3, 6-8, 6-15, 6-16
SIO port, 7-1
security-lock bits, 16-17
CCRs, See also chip configuration registers
Chip configuration
and bus contention, 15-11
and reset, 15-6
bytes, 15-5
waveform generator, 9-2
Block transfer mode‚ See PTS
BMOV instruction, A-2, A-9, A-45, A-49
BMOVI instruction, A-3, A-9, A-10, A-45, A-49
BR (indirect) instruction, A-2, A-10, A-49, A-55
Bus controller, 2-6, 16-6
Bus-control modes, 15-21–15-31
address valid strobe, 15-27–15-29
address valid with write strobe, 15-30–15-31
chip configuration register 0, 15-7, C-11
chip configuration register 1, 15-9, C-13
registers, 15-5
Clear, defined, 1-3
CLKOUT, 14-1, B-15
and internal timing, 2-7
and interrupts, 5-6
and RESET#, 13-8
idle, powerdown, reset status, B-24
reset status, 6-7
Index-2
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INDEX
Clock
external, 13-7
pin reset status, B-23, B-25
programming, 16-1–16-33
generator, 2-7, 13-7, 13-8
internal, and idle mode, 14-4, 14-5
phases, internal, 2-8
reset, 13-8, 13-9, 13-10, 13-11, 13-12
DI instruction, A-3, A-12, A-46, A-51, A-57
Digital-to-analog converter, 10-10
DIR bit, 7-2, 7-6
CLR instruction, A-2, A-10, A-41, A-47, A-52
CLRB instruction, A-2, A-11, A-41, A-47, A-52
CLRC instruction, A-3, A-11, A-46, A-51, A-57
CLRVT instruction, A-3, A-11, A-46, A-51, A-57
CMP instruction, A-3, A-11, A-43, A-47, A-52
CMPB instruction, A-3, A-11, A-44, A-47, A-52
CMPL instruction, A-2, A-12, A-45, A-47, A-52
Code execution, 2-5, 2-6
Direct addressing, 3-6, 3-9
DIV instruction, A-13, A-46, A-48, A-53
DIVB instruction, A-13, A-46, A-48, A-53
DIVU instruction, A-3, A-13, A-43, A-48, A-53
DIVUB instruction, A-3, A-14, A-44, A-48, A-53
DJNZ instruction, A-2, A-5, A-14, A-45, A-50,
A-56
COMP0_TIME, C-68
COMP1_CON, C-68
DJNZW instruction, A-2, A-5, A-14, A-45, A-50,
A-56
COMP1_TIME, C-68
Documents, related, 1-5–1-8
COMP5:0, 11-3, B-15
CompuServe forums, 1-10
Conditional jump instructions, A-5
Configuring external memory pins, 15-5
CPU, 2-4
DOUBLE-WORD, defined, 3-3
DPTS instruction, A-3, A-15, A-45, A-51, A-57
Dump-word routine, 16-24
E
CPVER, 16-12, B-15
Customer service, 1-8
EA#, 16-13, B-15
and P5.0, 6-13
and P5.3, 6-13
D
and programming modes, 16-14
idle, powerdown, reset status, B-24, B-25
EE opcode, and unimplemented opcode interrupt,
A-3, A-46
D/A converter, 10-10
Data instructions, A-49, A-55
Data types, 3-1–3-4
addressing restrictions, 3-1
converting between, 3-4
defined, 3-1
EI instruction, 5-13, A-3, A-15, A-46, A-51, A-57
EPA, 2-10, 11-1–11-24
and PTS, 11-12
iC-96, 3-1
block diagram, 11-2
PLM-96, 3-1
capture data overruns, 11-21
capture/compare channels
programming, 11-18
choosing capture or compare mode, 11-19
clock prescaler, 11-16, 11-17
compare channels
signed and unsigned, 3-1, 3-4
values permitted, 3-1
Datasheets
online, 1-10
ordering, 1-7
Deassert, defined, 1-3
DEC instruction, A-2, A-12, A-41, A-47, A-52
DECB instruction, A-2, A-12, A-41, A-47, A-52
DED bit, 16-6–16-7, 16-30
DEI bit, 16-6–16-7, 16-17
Design considerations
waveform generator, 9-19, 9-20
Device
programming, 11-18
compare modules
programming, 11-18
controlling the clock source and direction,
11-16, 11-17
determining event status, 11-24
enabling a timer/counter, 11-16, 11-17
enabling the compare function, 11-22
overruns, 11-12, 11-13
minimum hardware configuration, 13-1
Index-3
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8XC196MC, MD, MH USER’S MANUAL
re-enabling the compare event, 11-20, 11-22
reloading the waveform generator, 11-20,
11-23, C-16
A/D conversion time, 12-7
A/D error, 12-11
A/D sample time, 12-7
resetting the timer in compare mode, 11-21
resetting the timers, 11-21, 11-23
selecting the capture/compare event, 11-19
selecting the compare event, 11-22
selecting the time base, 11-19, 11-22
selecting up or down counting, 11-16, 11-17
signals, 11-2
A/D series resistance, 12-10
A/D threshold voltage, 12-5
A/D voltage drop, 12-11
capacitor size (powerdown circuit), 14-10
PH1 and PH2 frequency, 2-8
programming pulse width, OTPROM, 16-8
programming voltage, 16-15
SIO baud rate, 7-13
starting an A/D conversion, 11-20, 11-23,
C-16
state time, 2-8
See also port 1, port 6, PWM, timer/counters
EPA compare control x register, 11-22, C-15
EPA compare x time register, C-17
EPA control x register, 11-19, C-18
EPA time registers, C-21
FPAL-96, 3-4
FREQOUT, B-16
Frequency generator, 8-1–8-9
application example, 8-4–8-9
data encoding example, 8-5
block diagram, 8-1
EPA0_CON, C-68
EPA0_TIME, C-69
infrared remote control application, 8-5
EPA1_CON, C-68
EPA1_TIME, C-69
overview, 8-1–8-2
programming
EPA2_CON, C-69
frequency, 8-3
EPA2_TIME, C-69
output, 8-3
EPA3_CON, C-69
registers, 8-2
EPA3_TIME, C-69
status, 8-4
EPA4_CON, C-69
EPA4_TIME, C-69
Frequency generator count register, 8-4, C-22
Frequency register, 8-3, C-23
EPA5:0, 11-2, B-16
EPA5_CON, C-69
EPA5_TIME, C-69
H
Handbooks, ordering, 1-6
Hardware
EPTS instruction, 5-13, A-15, A-45, A-51, A-57
ESD protection, 6-3, 6-7, 13-5
Event processor array‚ See EPA
EXT instruction, A-2, A-15, A-41, A-47, A-52
EXTB instruction, A-2, A-16, A-41, A-47, A-52
EXTINT, 5-3, 14-7, B-16
A/D converter considerations, 12-10–12-13
addressing modes, 3-5
auto programming circuit, 16-26
device considerations, 13-1–13-13
device reset, 13-8, 13-10, 13-11, 13-12
interrupt processor, 2-6, 5-1
memory protection, 16-7, 16-17
minimum configuration, 13-1
NMI considerations, 5-6
and idle mode, 14-5
and powerdown mode, 14-6, 14-7
hardware considerations, 14-7
F
noise protection, 13-4
FaxBack service, 1-8
FE opcode
pin reset status, B-23, B-25
programming mode requirements, 16-13
reset instruction, 3-11
SIO port considerations, 7-8
slave programming circuit, 16-16
UPROM considerations, 16-7
and inhibiting interrupts, 5-9
Floating point library, 3-4
Formulas
A/D conversion result, 12-9, 12-13
Index-4
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INDEX
Hypertext manuals and datasheets, downloading,
1-10
Interrupt pending register, 5-21, C-27
Interrupts, 5-1–5-58
controller, 2-6, 5-1
end-of-PTS, 5-25
inhibiting, 5-9
latency, 5-9–5-11
calculating, 5-10
priorities, 5-4, 5-5
modifying, 5-18–5-19
procedures, PLM-96, 3-11
processing, 5-2
programming, 5-12–5-19
selecting PTS or standard service, 5-12
service routine
processing, 5-19
sources, 5-5
I
Idle mode, 2-11, 13-13, 14-4–14-5
entering, 14-5
pin status, B-23, B-25
timeout control, 11-7
IDLPD instruction, A-2, A-16, A-46, A-51, A-57
IDLPD #1, 14-5
IDLPD #2, 14-6
illegal operand, 13-9, 13-12
Immediate addressing, 3-6
INC instruction, A-2, A-16, A-41, A-47, A-52
INCB instruction, A-2, A-17, A-41, A-47, A-52
Indexed addressing, 3-9
and register RAM, 4-10
and windows, 4-19
Indirect addressing, 3-6
and register RAM, 4-10
with autoincrement, 3-7
Input pins
unused inputs, 13-2
vectors, 5-1, 5-5
vectors, memory locations, 4-3
Italics, defined, 1-3
J
level-sensitive, B-13
sampled, B-13
unused, 13-2
JBC instruction, A-2, A-5, A-17, A-41, A-50, A-56
JBS instruction, A-3, A-5, A-17, A-41, A-50, A-56
JC instruction, A-3, A-5, A-18, A-45, A-50, A-56
JE instruction, A-3, A-5, A-18, A-45, A-50, A-56
JGE instruction, A-2, A-5, A-18, A-45, A-50, A-56
JGT instruction, A-2, A-5, A-19, A-45, A-50, A-56
JH instruction, A-3, A-5, A-19, A-45, A-50, A-56
JLE instruction, A-3, A-5, A-19, A-45, A-50, A-56
JLT instruction, A-3, A-5, A-20, A-45, A-50, A-56
JNC instruction, A-2, A-5, A-20, A-45, A-50,
A-56
JNE instruction, A-2, A-5, A-20, A-45, A-50, A-56
JNH instruction, A-2, A-5, A-21, A-45, A-50,
A-56
JNST instruction, A-2, A-5, A-21, A-45, A-50,
A-56
INST, B-16
Instruction set, 3-1
and PSW flags, A-5
code execution, 2-5, 2-6
conventions, 1-3
execution times, A-52–A-53
lengths, A-47–A-52
opcode map, A-2–A-3
opcodes, A-41–A-46
overview, 3-1–3-4
protected instructions, 5-9
reference, A-1–A-3
See also RISM
INT_MASK, 14-2
JNV instruction, A-2, A-5, A-21, A-45, A-50,
A-56
JNVT instruction, A-2, A-5, A-22, A-45, A-50,
A-56
JST instruction, A-3, A-5, A-22, A-45, A-50, A-56
Jump instructions, A-55
INTEGER, defined, 3-3
Interfacing with external memory
configuring port pins, 15-5
registers, 15-4
signals, 15-1
Interrupt mask 1 register, 5-16, C-26
Interrupt mask register, 5-15, C-25
Interrupt pending 1 register, 5-22, C-28
conditional, A-5, A-50, A-56
unconditional, A-49
JV instruction, A-3, A-5, A-22, A-45, A-50, A-56
Index-5
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JVT instruction, A-3, A-5, A-23, A-45, A-50, A-56
Mode 4, SIO, 7-6
Modified quick-pulse algorithm, 16-9
MUL instruction, A-25, A-46, A-48, A-53
MULB instruction, A-25, A-46, A-48, A-53
Multiprocessor communications
SIO port, 7-8, 7-9
MULU instruction, A-3, A-26, A-42, A-43, A-46,
A-48, A-53
MULUB instruction, A-3, A-26, A-42, A-43,
A-48, A-53
L
Latency‚ See bus-hold protocol‚ interrupts
LCALL instruction, A-3, A-23, A-45, A-50, A-56
LD instruction, A-2, A-23, A-44, A-49, A-55
LDB instruction, A-2, A-23, A-44, A-49, A-55
LDBSE instruction, A-3, A-24, A-44, A-49, A-55
LDBZE instruction, A-3, A-24, A-44, A-49, A-55
Level-sensitive input, B-13
Literature, 1-11
N
LJMP instruction, A-2, A-24, A-49, A-55
Logical instructions, A-48, A-53
LONG-INTEGER, defined, 3-4
Naming conventions, 1-3–1-4
NEG instruction, A-2, A-27, A-41, A-48, A-53
Negative (N) flag, A-4, A-5, A-18, A-19, A-20
NEGB instruction, A-2, A-27, A-41, A-48, A-53
NMI, 5-3, 5-4, 5-6, B-16
Lookup tables, software protection, 3-11
M
hardware considerations, 5-6
Manual contents, summary, 1-1
Manuals, online, 1-10
Measurements, defined, 1-5
Memory bus, 2-6
idle, powerdown, reset status, B-24, B-25
Noise, reducing, 6-3, 6-4, 6-7, 12-12, 12-13, 13-4,
13-5, 13-6
NOP instruction, 3-11, A-3, A-27, A-46, A-51,
A-57
two-byte‚ See SKIP instruction
NORML instruction, 3-4, A-3, A-27, A-41, A-51,
A-57
NOT instruction, A-2, A-28, A-41, A-48, A-53
Notational conventions, 1-3–1-4
NOTB instruction, A-2, A-28, A-41, A-48, A-53
Numbers, conventions, 1-4
Memory controller, 2-4, 2-6
Memory map, 4-1, 4-2
Memory mapping
auto programming mode, 16-27
Memory partitions, 4-1–4-19
chip configuration bytes, 4-4
chip configuration registers, 4-4
interrupt and PTS vectors, 4-3
OTPROM, 16-2
program memory, 4-2, 16-2
register file, 4-9
register RAM, 4-10
O
ONCE mode, 2-11, 14-10
entering, 14-11
reserved memory, 4-3
security key, 4-4
exiting, 14-11
SFRs, 4-4
ONCE#, 14-2, B-17
special-purpose memory, 4-2, 4-3, 16-2
Memory protection, 16-3–16-7
CCR security-lock bits, 16-17
UPROM security bits, 16-7
Memory space, See memory partitions
Microcode engine, 2-4
Miller effect, 13-7
Ones register, C-29
Opcodes, A-41
EE, and unimplemented opcode interrupt,
A-3, A-46
FE, and signed multiply and divide, A-3
map, A-2
reserved, A-3, A-46
Mode 0, SIO, 7-5
Mode 1, SIO, 7-7
Mode 2, SIO, 7-9
Mode 3, SIO, 7-9
Operand types, See data types
Operands, addressing, 3-10
Operating modes, 2-11
OR instruction, A-2, A-28, A-43, A-48, A-53
Index-6
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INDEX
ORB instruction, A-2, A-28, A-43, A-48, A-53
Oscillator
P6_REG, C-69
P7.7:0, B-19
and powerdown mode, 14-5
external crystal, 13-6
on-chip, 13-5
PACT#, B-19
PALE#, 16-8, 16-10, 16-11, B-19
Parameters, passing to subroutines, 3-10
Parity, 7-7, 7-8, 7-9
PBUS, 16-12
OTPROM
controlling access to internal memory,
16-3–16-6
PBUS15:0, B-19
controlling fetches from external memory,
16-6–16-7
PC (program counter), 2-4
master, 2-6
memory map, 16-2
slave, 2-6
programming, 16-1–16-33
See also programming modes
ROM-dump mode, 16-30
verifying, 16-30
Peripheral Interrupt mask register, 5-17, C-35
Peripheral interrupt pending register, 5-23, C-37
Peripherals, internal, 2-8
Phase compare register, 9-17, C-59
Pin-out diagrams, B-3, B-4, B-5, B-7, B-8, B-11,
B-12
Overflow (V) flag, A-4, A-5, A-21, A-22
Overflow-trap (VT) flag, A-4, A-5, A-11, A-22,
A-23
PLM-96
conventions, 3-9, 3-10, 3-11
interrupt procedures, 3-11
PMODE, 16-11, 16-13
and programming modes, 16-14
PMODE3:0, B-19
P
P0.7:0, B-17
P0.7:4
and programming modes, 16-14
P0_PIN, C-69
P1.3:0, B-17
P1.7:0, B-17
P1_DIR, C-69
P1_MODE, C-69
P1_PIN, C-69
P1_REG, C-69
P2.2 considerations, 14-7
P2.7:0, B-18
P2_DIR, C-69
P2_MODE, C-69
P2_PIN, C-69
P2_REG, C-69
P3.7:0, B-18
P4.7:0, B-18
P5.0–P5.7
POP instruction, A-3, A-29, A-45, A-49, A-54
POPA instruction, A-2, A-29, A-46, A-49, A-54
POPF instruction, A-2, A-29, A-46, A-49, A-54
Port 0, 6-2, B-17
considerations, 6-4, 12-13, 13-5
idle, powerdown, reset status, B-25
input only pins, 6-2
overview, 6-1
structure, 6-3
Port 1, 6-2, B-17
considerations, 6-4, 6-12
idle, powerdown, reset status, B-23, B-25
input buffer, 6-7
input only pins, 6-2
logic tables, 6-9
operation, 6-4
overview, 6-1
SFRs, 6-6, 14-3
See also port 5
P5.7:0, B-18
P5_PIN
Port 2, 14-2, B-18
considerations, 6-12
idle, powerdown, reset status, B-23, B-25
operation, 6-4
overview, 6-1
P2.7 considerations, 6-12
P2.7 reset status, 6-7
SFRs, 6-6
P6.7:0, B-18
P6_DIR, C-69
P6_MODE, C-69
P6_PIN, C-69
Index-7
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8XC196MC, MD, MH USER’S MANUAL
SFRs, 6-6, 14-3
Port 3, B-18
enabling, 14-5
entering, 14-6
exiting, 14-6
addressing, 6-14
idle, powerdown, reset status, B-23, B-25
operation, 6-15–6-16
overview, 6-1
with EXTINT, 14-7–14-10
with RESET#, 14-6
with VPP, 14-6
pin configuration, 6-14
structure, 6-15
pin status, B-23
reset status, B-25
Port 4, B-18
Powerdown sequence, programming modes, 16-14
Prefetch queue, 2-6
addressing, 6-14
idle, powerdown, reset status, B-23, B-25
operation, 6-15–6-16
overview, 6-1
pin configuration, 6-14
structure, 6-15
Priority encoder, 5-4
Processor status word‚ See PSW
Product information, ordering, 1-6
PROG#, 16-10, 16-12, B-20
Program counter‚ See PC
Program memory, 4-2
Port 5, B-18
considerations, 6-12
idle, powerdown, reset status, B-23, B-25
operation, 6-4, 6-12
Program-word routine, 16-22
Programming
frequency generator
overview, 6-1
frequency, 8-3
pin configuration, 6-12
SFRs, 6-6, 14-3
Port 6, B-18
output, 8-3
Programming modes, 16-1–16-33
algorithms, 16-20, 16-21, 16-23, 16-28
auto, 16-2
configuration, 6-17
idle, powerdown, reset status, B-23, B-25
operation, 6-17
entering, 16-13, 16-14
exiting, 16-14
output configuration register, 6-18, C-62
overview, 6-1
Port 7, B-19
hardware requirements, 16-13
pin functions, 16-11–16-13
selecting, 16-13
idle, powerdown, reset status, B-24
operation, 6-4
serial port, 16-2
slave, 16-1
overview, 6-1
SFRs, 6-6, 14-3
Programming pulse width register, 16-8, C-39
Programming voltages, 13-1, 14-2, 16-13, B-21
calculating, 16-15
Port x data output register, C-34
Port x I/O direction register, C-30
Port x mode register, C-31
Port x pin input register, C-33
Port, serial‚ See SIO port
Ports
PSW, 2-4, 3-11, C-40
flags, and instructions, A-5
PTS, 2-4, 2-6, 2-11, 5-1
A/D scan mode, 5-32–5-37
and A/D converter, 5-33
asynchronous serial I/O receive mode,
5-55–5-58
general-purpose I/O, 2-9
unused inputs, 13-2
Power and ground pins
minimum hardware connections, 13-5
Power consumption, reducing, 2-11, 14-5
Power-up sequence, programming modes, 16-14
Powerdown mode, 2-11, 14-5–14-10
circuitry, external, 14-8, 14-10
disabling, 14-5
asynchronous serial I/O transmit mode,
5-50–5-54
block transfer mode, 5-30
control block, See PTSCB
cycle execution time, 5-12
cycle, defined, 5-30
initializing PTS control blocks, 5-24
Index-8
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INDEX
instructions, A-51, A-57
interrupt latency, 5-11
interrupt processing flow, 5-2
routine, defined, 5-1
Q
Quadrature clocking, 11-7
Quick reference guides, ordering, 1-8
serial I/O modes, 5-37–5-58
single transfer mode, 5-27
synchronous serial I/O receive mode,
5-47–5-50
synchronous serial I/O transmit mode,
5-43–5-46
R
RALU, 2-4–2-6
RD#, B-20
considerations, 6-13
idle, powerdown, reset status, B-23, B-25
Read cycles
vectors, memory locations, 4-3
See also PWM
16-bit data bus, 15-14
8-bit data bus, 15-16
PTS select register, 5-14, C-42
PTS service register, 5-26, C-43
PTSCB, 5-4, 5-9
READY, 15-17–15-21, 16-25
and wait states, 15-18
considerations, 6-13
idle, powerdown, reset status, B-23, B-25
timing definitions, 15-20
timing diagram, 15-19
timing requirements, 15-18
REAL variables, 3-4
A/D scan mode, 5-33
block transfer mode, 5-31
memory locations, 4-3
PTSCON register, 5-27
PTSCOUNT register, 5-25
single transfer mode, 5-28
PTSCB1
serial I/O mode, 5-38
PTSCB2
Register bits
naming conventions, 1-4
reserved, 1-4
Register file, 2-4, 4-9
and windowing, 4-9, 4-12
See also windows
serial I/O mode, 5-41
Pulse-width modulator, See PWM
PUSH instruction, A-3, A-29, A-45, A-49, A-54
PUSHA instruction, A-2, A-30, A-46, A-49, A-54
PUSHF instruction, A-2, A-30, A-46, A-49, A-54
PVER, 16-9, 16-11, B-20
PWM, 10-1
Register RAM, 4-10
and idle mode, 14-4
and powerdown mode, 14-5
Register-direct addressing, 4-10
and register RAM, 4-10
and windows, 4-12, 4-19
Registers
and cascading timer/counters, 11-7
block diagram, 10-2
D/A converter, 10-10
duty cycle, 10-4
enabling outputs, 10-8
generating analog outputs, 10-10
highest-speed, 11-14
low-speed, 11-7, 11-13
AD_COMMAND, 12-8, C-6
AD_RESULT (read), 12-9, C-7
AD_RESULT (write), 12-6, C-8
AD_TEST, 12-5, C-9
AD_TIME, 12-7, C-10
addresses and reset values, C-2
allocating, 3-10
CCR0, 15-7, C-11
CCR1, 15-9, C-13
COMPx_CON, 11-22, C-15
COMPx_TIME, C-17
EPAx_CON, 11-19, C-18
EPAx_TIME, C-21
overview, 10-1
programming duty cycle, 10-4
typical waveforms, 10-4
with dedicated timer/counter, 11-14
PWM control x register, 10-7, C-46
PWM count register, 10-8, C-44
PWM period register, 10-6, C-45
PWM1:0, B-20
external memory, 15-4
Index-9
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8XC196MC, MD, MH USER’S MANUAL
FREQ_CNT, 8-4, C-22
FREQ_GEN, 8-3, C-23
GEN_CON, 13-9, C-24
grouped by modules, C-1
INT_MASK, 5-15, C-25
INT_MASK1, 5-16, 7-2, C-26
INT_PEND, 5-21, 7-3, C-27
INT_PEND1, 5-22, 7-3, C-28
naming conventions, 1-4
ONES_REG, C-29
SP1_CON, 7-4
SP1_STATUS, 7-4
SPx_BAUD, 7-12, C-50
SPx_CON, 7-10, C-51
SPx_STAUS, 7-15, C-52
T1CONTROL, 11-16, C-53
T1RELOAD, C-54
T2CONTROL, 11-17, C-55
TIMERx, C-56
USFR, 16-7, C-57
P0_PIN, 6-3, 6-4
using, 3-9
P1_MODE
WATCHDOG, C-58
considerations, 6-12
P1_PIN, 6-3, 6-4, 7-3
P2_MODE
considerations, 6-12
P2_REG
considerations, 6-12
P5_MODE
considerations, 6-12, 6-13
PI_MASK, 5-17, 7-4, C-35
PI_PEND, 5-23, 7-4, C-37
PPW, 16-8, C-39
WG_COMPx, 9-17, C-59
WG_CONTROL, 9-18, C-60
WG_COUNTER, 9-19, C-61
WG_OUTPUT (port 6), 6-17, 6-18, C-62
WG_OUTPUT (waveform generator), 9-13,
C-63
WG_PROTECT, 9-15, C-66
WG_RELOAD, 9-16, C-67
WSR, 4-12, C-68
ZERO_REG, C-71
Reserved bits, defined, 1-4
Reset, 13-9
PSW, C-40
PTSSEL, 5-14, C-42
PTSSRV, 5-26, C-43
PWM_COUNT, 10-8, C-44
PWM_PERIOD, 10-6, C-45
PWMx_CONTROL, 10-7, C-46
Px_DIR, 6-6, 6-9, 6-10, 6-11, C-30
Px_MODE, 6-6, 6-9, 6-10, 6-11, C-31
Px_PIN, 6-2, 6-6, 6-7, 6-9, 6-14, 6-16, C-33
Px_REG, 6-6, 6-9, 6-10, 6-11, 6-14, 6-16,
C-34
and CCB fetches, 4-4
circuit diagram, 13-11
general configuration register, 13-9, C-24
pin status, B-23, B-25
status
CLKOUT/P2.7, 6-7
with illegal IDLPD operand, 13-12
with RESET# pin, 13-10
with RST instruction, 13-9, 13-12
with watchdog timer, 13-12
RESET#, 13-1, 14-2, B-20
and CCB fetch, 13-8
RALU, 2-4, 2-5, 4-10
reset values and addresses, C-2
SBUF0_RX, 7-4
and CLKOUT, 13-8
SBUF0_TX, 7-4
SBUF1_RX, 7-4
SBUF1_TX, 7-4
SBUFx_RX, C-47
SBUFx_TX, C-48
SP, C-49
SP_PPW, 16-8
SP0_BAUD, 7-4
and device reset, 13-8, 13-9, 13-10
and ONCE mode, 14-11
and powerdown mode, 14-6
and programming modes, 16-13, 16-14
idle, powerdown, reset status, B-24, B-25
Resonator, ceramic, 13-6
RET instruction, A-2, A-30, A-46, A-50, A-55,
A-56
SP0_CON, 7-4
SP0_STATUS, 7-4
ROM-dump mode, 16-30
security key verification, 16-30
SP1_BAUD, 7-4
Index-10
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INDEX
RST instruction, 3-11, 13-9, 13-12, A-3, A-31,
A-46, A-51, A-57
Run-time programming, 16-32–16-33
code example, 16-33
SHRL instruction, A-3, A-36, A-41, A-51, A-57
Signals
configuring for external memory interfacing,
15-5
default conditions, B-23, B-25
descriptions, B-13–B-22
external memory, 15-1
AD15:0, 15-1
RXD, B-20
and SIO port mode 0, 7-5, 7-7
and SIO port modes 1, 2, and 3, 7-7
ADV#, 15-1
ALE, 15-2
BHE#, 15-2
BUSWIDTH, 15-2
CLKOUT, 15-2
EA#, 15-3
INST, 15-3
RD#, 15-3
READY, 15-3
S
Sampled input, B-13
SBUFx_RX, C-70
SBUFx_TX, C-70
SCALL instruction, A-3, A-31, A-41, A-47, A-50,
A-55, A-56
SCLKx#, 7-2
Security key
verification, 16-30
WR#, 15-3
WRH#, 15-4
WRL#, 15-4
Serial I/O modes, See PTS
Serial I/O port‚ See SIO port
Serial port control x register, 7-10, C-51
Serial port receive buffer x register, C-47
Serial port status x register, 7-15, C-52
Serial port transmit buffer x register, C-48
Serial port x baud rate register, 7-12, C-50
Set, defined, 1-3
functional listings, B-2, B-6, B-9
name changes, B-1
naming conventions, 1-4
Single transfer mode‚ See PTS
SIO port, 2-9, 7-1
9-bit data‚ See mode 2‚ mode 3
block diagram, 7-1
calculating baud rate, 7-13, 7-14
enabling interrupts, 7-14
enabling parity, 7-10–??
framing error, 7-16
half-duplex considerations, 7-8
interrupts, 7-7, 7-9, 7-16
mode 0, 7-5–7-6
mode 1, 7-7
mode 2, 7-7, 7-8
mode 3, 7-7, 7-9
multiprocessor communications, 7-8, 7-9
overrun error, 7-16
programming, 7-10
receive interrupt (RI) flag, 7-16
selecting baud rate, 7-12–7-14
SFRs, 7-2
SETC instruction, A-3, A-31, A-46, A-51, A-57
SFRs
and idle mode, 14-4
and powerdown mode, 14-5
CPU, 4-11
memory-mapped, 4-5
peripheral, 4-4, 4-5
and windowing, 4-12
reserved, 3-10, 4-4, 4-11
with indirect or indexed operations, 3-10, 4-4,
4-11
with read-modify-write instructions, 4-4
Shift instructions, A-51, A-57
SHL instruction, A-3, A-32, A-41, A-51, A-57
SHLB instruction, A-3, A-32, A-41, A-51, A-57
SHLL instruction, A-3, A-33, A-41, A-51
SHORT-INTEGER, defined, 3-2
SHR instruction, A-3, A-33, A-41, A-51, A-57
SHRA instruction, A-3, A-34, A-41, A-51, A-57
SHRAB instruction, A-3, A-34, A-41, A-51, A-57
SHRAL instruction, A-3, A-35, A-41, A-51, A-57
SHRB instruction, A-3, A-35, A-41, A-51, A-57
signals, 7-2
status, 7-15–7-16
transmit interrupt (TI) flag, 7-16
See also mode 0‚ mode 1‚ mode 2‚ mode 3‚
port 2
Index-11
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8XC196MC, MD, MH USER’S MANUAL
SJMP instruction, A-2, A-36, A-41, A-47, A-49,
A-55
SKIP instruction, A-2, A-36, A-41, A-51, A-57
Slave programming mode, 16-15–16-24
address/command decoder routine, 16-19,
16-20
Subroutines
linking, 3-10
nested, 4-10
Symbols
signal status, B-23
System bus timing, 15-32
algorithm, 16-19–16-24
circuit, 16-16
dump-word routine, 16-19, 16-23
entering, 16-19
program-word routine, 16-19, 16-21
security key programming, 16-15
timings, 16-22, 16-24
T
T1CLK, 11-2, B-21
T1CONTROL, C-70
T1DIR, 11-2, B-21
T1RELOAD, C-70
T2CONTROL, C-70
Technical support, 1-11
Terminology, 1-3
Software
addressing modes, 3-9
conventions, 3-9–3-11
TIJMP instruction, A-2, A-39, A-45, A-49, A-55
Timer 1 control register, 11-16, C-53
Timer 1 reload register, C-54
Timer 2 control register, 11-17, C-55
Timer x register, C-56
Timer, watchdog‚ See watchdog timer
Timer/counters, 2-10
and PWM, 11-13, 11-14
cascading, 11-7
device reset, 13-12
interrupt service routines, 5-19
linking subroutines, 3-10
protection, 3-11
trap interrupt, 5-4, 5-6, 5-9
SP_STATUS, 7-15
SPE bit, 7-3
Special instructions, A-51, A-57
Special operating modes
SFRs, 14-2
Special-purpose memory, 4-2
SPx bit, 7-4
SPx_BAUD, C-70
SPx_CON, C-70
count rate, 11-6
programming, 11-15
quadrature clocking, 11-7
resolution, 11-6
signals, 11-2
See also EPA
SPx_STATUS, C-70
TIMER1, C-70
ST instruction, A-2, A-37, A-45, A-49, A-55
Stack instructions, A-49, A-54
Stack pointer, 4-10, C-49
and subroutine call, 4-10
initializing, 4-11
Standard bus-control mode
decoding WRL# and WRH#, 15-22
example system, 15-23
TIMER2, C-70
Timing
dump-word routine, 16-24
instruction execution, A-52–A-53
internal, 2-7, 2-8
interrupt latency, 5-9–5-12, 5-30
program-word routine, 16-22
PTS cycles, 5-12
signals, 15-22
State time, defined, 2-8
SIO port mode 0, 7-6, 7-7
SIO port mode 1, 7-8
SIO port mode 2, 7-9
SIO port mode 3, 7-9
slave programming routines, 16-22, 16-24
Timing definitions
STB instruction, A-2, A-37, A-45, A-49, A-55
Sticky bit (ST) flag, 3-4, A-4, A-5, A-21, A-22
SUB instruction, A-3, A-37, A-42, A-47, A-52
SUBB instruction, A-3, A-38, A-42, A-43, A-47,
A-52
BUSWIDTH, 15-13
READY, 15-20
SUBC instruction, A-3, A-38, A-44, A-47, A-52
SUBCB instruction, A-3, A-38, A-44, A-47, A-52
Index-12
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INDEX
Timing diagrams
16-bit data bus, 15-15
and duty cycle, 9-19
generator circuitry, 9-5
8-bit data bus, 15-17
BUSWIDTH, 15-12
READY, 15-19
design considerations, 9-19, 9-20
EXTINT interrupts and protection circuitry,
9-21
system bus timing, 15-32
Timing requirements
BUSWIDTH, 15-13
READY, 15-18
TRAP instruction, 5-6, A-2, A-39, A-46, A-50,
A-55, A-56
interrupts, 9-20
operating modes, 9-7, 9-11
center-aligned, 9-8, 9-9, 9-10
edge-aligned, 9-8, 9-10, 9-11
overview, 9-1
phase driver channels, 9-5
programming, 9-12, 9-20
carrier period, 9-16
TRAP interrupt, 5-4
TXD, B-21
and SIO port mode 0, 7-5
EXTINT
interrupts, 9-15
outputs, 9-12, C-63–C-65
protection circuitry, 9-15
programming example, 9-21, 9-25
protection circuitry, 9-6
register
buffering and synchronization, 9-6, 9-7
updates, 9-8
registers, 9-3, 9-4
U
UART, 2-9, 7-1
Unerasable PROM register, 16-7, C-57
Unimplemented opcode interrupt, 3-11, 5-4, 5-6,
5-9
Units of measure, defined, 1-5
Universal asynchronous receiver and transmitter‚
See UART
UPROM, 16-6
programming, 16-6–16-7
USFR, 16-7
signals, 9-3
status, 9-19
timebase generator, 9-4
Waveform generator control register, 9-18, C-60
Waveform generator counter register, 9-19, C-61
Waveform generator output configuration register,
9-13, C-63
Waveform generator reload register, 9-16, C-67
Waveform protection register, 9-15, C-66
WDE bit, 13-12
WG3:1, B-22
WG3:1#, B-22
Window selection register‚ See WSR
Windowing, 4-12–4-19
examples, 4-16–4-19
V
VCC, 13-1, B-21
and programming modes, 16-14
VPP, 13-1, 14-2, 16-13, B-21
and programming modes, 16-14
V
REF, 12-5, 13-1, B-21
VSS, 13-1, B-21
and programming modes, 16-14
W
Wait states, 15-17–15-20
controlling, 15-18
See also windows
Windows, 4-12–4-19
Watchdog timer, 2-11, 3-11, 3-12, 13-9, 13-12
and idle mode, 14-5
selecting reset interval, 13-13
Watchdog timer register, C-58
Waveform generator, 9-1, 9-25
block diagram, 9-2
addressing, 4-16
and addressing modes, 4-19
and memory-mapped SFRs, 4-15
base address, 4-14, 4-15
locations that cannot be windowed, 4-15
offset address, 4-14
control and protection circuitry, 9-5
dead time
selecting, 4-13
setting up with linker loader, 4-17
Index-13
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8XC196MC, MD, MH USER’S MANUAL
WSR values and direct addresses, 4-15
WORD, defined, 3-2
World Wide Web, 1-11
WR#, B-22
idle, powerdown, reset status, B-23, B-25
WRH#, B-22
Write cycles
16-bit data bus, 15-14
8-bit data bus, 15-16
Write strobe mode
example system, 15-26
signals, 15-25
WRL#, B-22
WSR, 4-13, C-68
X
X, defined, 1-5
x, defined, 1-3
XCH instruction, A-2, A-3, A-40, A-41, A-49,
A-55
XCHB instruction, A-2, A-3, A-40, A-41, A-49,
A-55
XOR instruction, A-2, A-40, A-43, A-48, A-53
XORB instruction, A-2, A-40, A-43, A-44, A-48,
A-53
XTAL1, 13-2, B-22
and Miller effect, 13-7
and programming modes, 16-13
and SIO baud rate, 7-14
hardware connections, 13-6, 13-7
XTAL2, 13-2, B-22
hardware connections, 13-6, 13-7
Y
y, defined, 1-3
Z
Zero (Z) flag, A-4, A-5, A-18, A-19, A-20, A-21
Zero register, C-71
Index-14
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