Intel Computer Hardware SA 1100 User Manual

®
®
Intel StrongARM SA-1100  
Microprocessor  
Developer’s Manual  
August 1999  
Order Number: 278088-004  
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Contents  
Introduction......................................................................................................................1-1  
Functional Description.....................................................................................................2-1  
ARM™ Implementation Options......................................................................................3-1  
Instruction Set .................................................................................................................4-1  
Coprocessors ..................................................................................................................5-1  
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Caches, Write Buffer, and Read Buffer...........................................................................6-1  
Memory-Management Unit (MMU)..................................................................................7-1  
Clocks .............................................................................................................................8-1  
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System Control Module...................................................................................................9-1  
9.1.1.3 GPIO Pin Output Set Register (GPSR) and  
9.1.1.4 GPIO Rising-Edge Detect Register (GRER) and  
9.2.1.2 Interrupt Controller IRQ Pending Register (ICIP) and  
9.4.2 OS Timer Match Registers 0–3  
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Memory and PCMCIA Control Module..........................................................................10-1  
10.2.2 DRAM CAS Waveform Shift Registers  
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Peripheral Control Module.............................................................................................11-1  
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11.7.11.1LCD Disable Done Flag (LDD)  
11.7.11.2Base Address Update Flag (BAU)  
11.7.11.3Bus Error Status (BER)  
11.7.11.4AC Bias Count Status (ABC)  
11.7.11.5Input FIFO Overrun Lower Panel Status (IOL)  
11.7.11.6Input FIFO Underrun Lower Panel Status (IUL)  
11.7.11.7Input FIFO Overrun Upper Panel Status (IOU)  
11.7.11.8Input FIFO Underrun Upper Panel Status (IUU)  
11.7.11.9Output FIFO Overrun Lower Panel Status (OOL)  
11.7.11.10Output FIFO Underrun Lower Panel Status (OUL)  
11.7.11.11Output FIFO Overrun Upper Panel Status (OOU)  
11.7.11.12Output FIFO Underrun Upper Panel Status (OUU)  
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11.9.8.1End/Error in FIFO Status (EIF)  
11.9.8.2Transmit Underrun Status (TUR)  
11.9.8.3Receiver Abort Status (RAB)  
11.9.8.4Transmit FIFO Service Request Flag (TFS)  
11.9.8.5Receive FIFO Service Request Flag (RFS)  
11.9.9.1Receiver Synchronized Flag (RSY)  
11.9.9.2Transmitter Busy Flag (TBY)  
11.9.9.3Receive FIFO Not Empty Flag (RNE)  
11.9.9.4Transmit FIFO Not Full Flag (TNF)  
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11.9.9.5Receive Transition Detect Status (RTD)  
11.9.9.6End of Frame Flag (EOF)  
11.9.9.7CRC Error Status (CRE)  
11.9.9.8Receiver Overrun Status (ROR)  
11.10.10.1End/Error in FIFO Status (EIF)  
11.10.10.2Transmit Underrun Status (TUR)  
11.10.10.3Receiver Abort Status (RAB)  
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11.10.10.4Transmit FIFO Service Request Flag (TFS)  
11.10.10.5Receive FIFO Service Request Flag (RFS)  
11.10.10.6Framing Error Status (FRE)  
11.10.11.1Receiver Synchronized Flag (RSY)  
11.10.11.2Transmitter Busy Flag (TBY)  
11.10.11.3Receive FIFO Not Empty Flag (RNE)  
11.10.11.4Transmit FIFO Not Full Flag (TNF)  
11.10.11.5End-of-Frame Flag (EOF)  
11.10.11.6CRC Error Status (CRE)  
11.10.11.7Receiver Overrun Status (ROR)  
11.11.7.1Transmit FIFO Service Request Flag (TFS)  
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11.11.7.2Receive FIFO Service Request Flag (RFS)  
11.11.7.3Receiver Idle Status (RID)  
11.11.7.4Receiver Begin of Break Status (RBB)  
11.11.7.5Receiver End of Break Status (REB)  
11.11.7.6Error in FIFO Flag (EIF)  
11.11.8.1Transmitter Busy Flag (TBY  
11.11.8.2Receive FIFO Not Empty Flag (RNE)  
11.11.8.3Transmit FIFO Not Full Flag (TNF)  
11.11.8.4Parity Error Flag (PRE)  
11.11.8.5Framing Error Flag (FRE)  
11.11.8.6Receiver Overrun Flag (ROR)  
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11.12.6.1Audio Transmit FIFO Service Request Flag (ATS)  
11.12.6.2Audio Receive FIFO Service Request Flag (ARS)  
11.12.6.3Telecom Transmit FIFO Service Request Flag (TTS)  
11.12.6.4Telecom Receive FIFO Service Request Flag (TRS)  
11.12.6.5Audio Transmit FIFO Underrun Status (ATU)  
11.12.6.6Audio Receive FIFO Overrun Status (ARO)  
11.12.6.7Telecom Transmit FIFO Underrun Status (TTU)  
11.12.6.8Telecom Receive FIFO Overrun Status (TRO)  
11.12.6.9Audio Transmit FIFO Not Full Flag (ANF)  
11.12.6.10Audio Receive FIFO Not Empty Flag (ANE)  
11.12.6.11Telecom Transmit FIFO Not Full Flag (TNF)  
11.12.6.12Telecom Receive FIFO Not Empty Flag (TNE)  
11.12.6.13Codec Write Completed Flag (CWC)  
11.12.6.14Codec Read Completed Flag (CRC)  
11.12.6.15Audio Codec Enabled Flag (ACE)  
11.12.6.16Telecom Codec Enabled Flag (TCE)  
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11.12.12.1Transmit FIFO Not Full Flag (TNF)  
11.12.12.2Receive FIFO Not Empty Flag (RNE)  
11.12.12.3SSP Busy Flag (BSY)  
11.12.12.4Transmit FIFO Service Request Flag (TFS)  
11.12.12.5Receive FIFO Service Request Flag (RFS)  
11.12.12.6Receiver Overrun Status (ROR)  
DC Parameters..............................................................................................................12-1  
AC Parameters..............................................................................................................13-1  
Package and Pinout ......................................................................................................14-1  
Debug Support ..............................................................................................................15-1  
Boundary-Scan Test Interface.......................................................................................16-1  
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Register Summary ......................................................................................................... A-1  
3.6864–MHz Oscillator Specifications............................................................................ B-1  
B.1.1.1. Parasitic Capacitance Off-chip  
B.1.1.2. Parasitic Capacitance Off-chip  
32.768–kHz Oscillator Specifications............................................................................. C-1  
C.1.1.5.Parasitic Capacitance Off-chip  
C.1.1.6.Parasitic Capacitance Off-chip  
Internal Test ................................................................................................................... D-1  
xvi  
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Figures  
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Tables  
9-2  
SA-1100 Power and Clock Supply Sources and States  
xviii  
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Introduction  
1
1.1  
Intel® StrongARM® SA-1100 Microprocessor  
The Intel® StrongARM® SA-1100 Microprocessor (SA-1100) is the second member of the  
StrongARM® family. It is a highly integrated communications microcontroller that incorporates a  
32-bit StrongARM® RISC processor core, system support logic, multiple communication  
channels, an LCD controller, a PCMCIA controller, and general-purpose I/O ports.  
As does the Intel® StrongARM® SA-110 Microprocessor (SA-110), the first member of the  
StrongARM family, the SA-1100 provides power efficiency, low cost, and high performance.  
Figure 1-1 shows the features of the SA-1100. The shaded boxes are features that have carried over  
with few or no changes from the SA-110. The nonshaded boxes are new or updated features for the  
SA-1100.  
Figure 1-1. SA-1100 Features  
Read Buffer  
16KB  
Instruction  
Cache  
JTAG  
IMMU  
8KB  
®
Intel  
Data Cache  
®
DMMU  
*
StrongARM  
CPU  
512-byte  
MiniDcache  
Write  
Buffer  
General-Purpose  
I/O  
Interrupt  
Controller  
Serial  
Controllers  
Memory/  
Controller  
DMA  
Controller  
LCD  
Controller  
Real-Time  
Clock  
Interval  
Timer  
* StrongARM is a registered trademark of ARM Limited.  
A6830-01  
SA-1100 SA-1100 Developer’s Manual  
1-1  
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Introduction  
Table 1-1.  
Features of the SA-1100 CPU for AA and EA Parts  
High Performance  
3.3 V I/O interface  
— 150 Dhrystone 2.1 MIPS @ 133 MHz  
— 220 Dhrystone 2.1 MIPS @ 190 MHz  
Low power (normal mode)†  
— <230 mW @1.5 V/133 MHz  
— <330 mW @ 1.5 V/200 MHz  
Integrated clock generation  
— Internal phase-locked loop (PLL)  
— 3.686 MHz oscillator  
208-pin thin quad flat pack (LQFP)††  
256 mini-ball grid array (mBGA)  
32-way set-associative caches  
— 16 Kbyte instruction cache  
— 8 Kbyte write-back data cache  
32-entry memory-management units  
— Maps 4 Kbyte, 8 Kbyte, or 1 Mbyte  
Write buffer  
— 32.768 kHz oscillator  
— 8-entry, between 1 and 16 bytes each  
Read buffer  
Power-management features  
— Normal (full-on) mode  
— 4-entry, 1, 4, or 8 words  
— Idle (power-down) mode  
Memory bus  
— Sleep (power-down) mode  
Big and little endian operating modes  
— Interfaces to ROM, Flash, SRAM,  
and DRAM  
— Supports two PCMCIA sockets  
Power dissipation, particularly in idle mode, is strongly dependent on the details of the system design.  
†† Package nomenclature has been modified due to industry standardization of packages. LQFP is 1.4mm  
thick, thin quad flat pack. Please note that no modification has been made to the package itself.  
Table 1-2.  
Features of the SA-1100 CPU for CA and DA Parts  
High Performance  
256 mini-ball grid array (mBGA)  
— 180 Dhrystone 2.1 MIPS @ 160 MHZ 32-way set-associative caches  
— 250 Dhrystone 2.1 MIPS @ 220 MHz  
Low power (normal mode)†  
— <430 mW @ 2.0-V/160-MHz  
— <550 mW @ 2.0-V/220-MHz  
Integrated clock generation  
— Internal phase-locked loop (PLL)  
— 3.686-MHz oscillator  
— 16 Kbyte instruction cache  
— 8 Kbyte write-back data cache  
32-entry memory-management units  
— Maps 4 Kbyte, 8 Kbyte, or 1 Mbyte  
Write buffer  
— 8-entry, between 1 and 16 bytes each  
Read buffer  
— 32.768-kHz oscillator  
— 4-entry, 1, 4, or 8 words  
Memory bus  
Big and little endian operating modes  
3.3-V I/O interface  
— Interfaces to ROM, Flash, SRAM,  
and DRAM  
208-pin thin quad flat pack (LQFP)††  
— Supports two PCMCIA sockets  
Power dissipation, particularly in idle mode, is strongly dependent on the details of the system design.  
†† Package nomenclature has been modified due to industry standardization of packages. LQFP is 1.4mm  
thick, thin quad flat pack. Please note that no modification has been made to the package itself.  
1-2  
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Introduction  
Table 1-3.  
Changes to the SA-1100 Core from the SA-110  
Data cache reduced from 16 Kbyte to  
Hardware breakpoints  
8 Kbyte  
Memory-management unit (MMU)  
Interrupt vector address adjust capability  
Read buffer (nonblocking)  
enhancements  
Process ID mapping  
Minicache for alternate data caching  
Table 1-4.  
Additional Features Built into SA-1100 Chipset  
Memory controller supporting ROM,  
Twenty-eight general-purpose I/O ports  
Flash, EDO, standard DRAM, and SRAM  
Real-time clock with interrupt capability  
On-chip oscillators for clock sources  
Interrupt controller  
LCD controller  
— 1-, 2-, or 4-bit gray-scale levels  
— 8-, 12-, or 16-bit color levels  
Power-management features  
— Normal (full-on) mode  
Serial communications module supporting  
SDLC  
— Idle (power-down) mode  
230-Kbps UART  
— Sleep (power-down) mode  
Touch-screen, audio, telecom port  
Infrared data (IrDA) serial port  
— 115 Kbps, 4 Mbps  
Four general-purpose interruptible timers  
12-Mbps USB device controller  
Synchronous serial port (UCB1100,  
Six-channel DMA controller  
Integrated two-slot PCMCIA controller  
UCB1200, SPI, TI, Wire)  
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1-3  
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Introduction  
1.2  
Overview  
The SA-1100 Microprocessor (SA-1100) is a general-purpose, 32-bit RISC microprocessor with a  
16 Kbyte instruction cache, an 8 Kbyte write-back data cache, a minicache, a write buffer, a read  
buffer, and a memory management unit (MMU) combined in a single chip. The SA-1100 is  
software compatible with the ARMV4 architecture processor family and can be used with ARM  
support chips such as I/O, memory, and video. The core of the SA-1100 is derived from the core of  
the SA-110 Microprocessor (SA-110), with the following changes:  
Reduction in size of the data cache from 16 Kbyte to 8 Kbyte  
Addition of a 512-byte mini data cache that allocates data based on MMU settings  
Addition of debug support in the form of address and data breakpoints  
Addition of a four-entry read buffer to facilitate software-controlled data prefetching  
Addition of vector address adjust capability  
Addition of a process ID register  
The logic outside the core and caches is grouped into the following three modules:  
Memory and PCMCIA control module (MPCM)  
— Memory interface supporting ROM, Flash, DRAM, SRAM and PCMCIA control signals  
System control module (SCM)  
— Twenty-eight general-purpose interruptible I/O ports  
— Real-time clock, watchdog, and interval timers  
— Power management controller  
— Interrupt controller  
— Reset controller  
— Two on-chip oscillators for connection to 3.686 MHz and 32.768 kHz crystals  
Peripheral control module (PCM)  
— Six-channel DMA controller  
— Gray/color, active/passive LCD controller  
— 230 Kbps SDLC controller  
— 16550-compatible UART  
— IrDA serial port (115 Kbps, 4 Mbps)  
— Synchronous serial port (UCB1100, UCB1200, SPI, TI, µWire)  
— Universal serial bus (USB) device controller  
1-4  
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Introduction  
The instruction set comprises eight basic instruction types:  
Two make use of on-chip arithmetic logic unit, barrel shifter, and multiplier to perform  
high-speed operations on data in a bank of 16 logical registers (31 physical registers), each 32  
bits wide.  
Three classes of instructions control data transfer between memory and the registers: one  
optimized for flexibility of addressing, one for rapid context switching, and one for swapping  
data.  
Two instructions control the flow and privilege level of execution.  
One class is used to access the privileged state of the CPU.  
The ARM instruction set is a good target for compilers of many different high-level languages.  
Where required for critical code segments, assembly code programming is also straightforward,  
unlike some RISC processors that need sophisticated compiler technology to manage complicated  
instruction interdependencies.  
The SA-1100 is a static part and has been designed to run at a reduced voltage to minimize its power  
requirements. This makes it a good choice for portable applications where both of these features are  
essential.  
1.3  
Example System  
Figure 1-2 shows how the SA-1100 can be used in a hand-held computing device.  
Figure 1-2. SA-1100 Example System  
UART or LocalTalk  
Communications  
Gray Scale  
or  
Color LCD  
Display  
Tablet / Serial  
Keyboard  
®
®*  
Intel StrongARM  
SA-1100  
Portable  
3.686  
MHz  
Codec  
Communications  
Microcontroller  
Infrared  
Communications  
32.768  
KHz  
USB Synchronization  
Port  
Glue Logic  
DRAM  
ROM  
PCMCIA Interface  
(Flash, Modem)  
Flash  
* StrongARM is a registered trademark of ARM Limited.  
A6870-01  
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Introduction  
1.4  
ARM™ Architecture  
The SA-1100 implements the ARM V4 architecture as defined in the ARM Architecture Reference,  
28-July-1995, with the following options:  
1.4.1  
1.4.2  
26-Bit Mode  
The SA-1100 supports 26-bit mode but all exceptions are initiated in 32-bit mode. The P and D bits  
do not affect the operation of SA-1100; they are always read as ones and writes to them are  
ignored.  
Coprocessors  
The SA-1100 supports MCR and MRC access to coprocessor number 15. These instructions are  
used to access the memory-management, configuration, and cache control registers. In addition,  
coprocessor 15 provides control for read buffer fills and flushes, and hardware breakpoints. All  
other coprocessor instructions cause an undefined instruction exception. No support for external  
coprocessors is provided.  
1.4.3  
Memory Management  
Memory management exceptions preserve the base address registers so that no code is required to  
restore state. Separate translation lookaside buffers (TLBs) are implemented for the instruction and  
data streams. Each TLB has 32 entries that can each map a segment, a large page, or a small page.  
The TLB replacement algorithm is round robin. The data TLBs support both the flush-all and  
flush-single-entry operations, while the instruction TLBs support only the flush-all operation.  
1.4.4  
1.4.5  
Instruction Cache  
The SA-1100 has a 16 Kbyte instruction cache (Icache) with 32-byte blocks and 32-way  
associativity. The cache supports the flush-all function. Replacement is round robin within a set.  
The Icache can be enabled while memory management is disabled. When memory management is  
disabled, all memory is considered cacheable by the Icache.  
Data Cache  
The SA-1100 has an 8 Kbyte data cache (Dcache) with 32-byte blocks and 32-way associativity.  
The cache supports the flush-all, flush-entry, and copyback-entry functions. The copyback-all  
function is not supported in hardware. This function can be provided by software. The cache is read  
allocate with round-robin replacement.  
The Dcache has been augmented with a 16-entry, two-way set associative minicache that allocates  
when the MMU b and c bits are 0 and 1, respectively. This cache is accessed in parallel with the  
main Dcache. Replacement victims in this cache are replaced based on a least-recently-used (LRU)  
algorithm. This cache is useful for applications that access large data structures and would  
normally thrash the main Dcache. Instead, these data structures can be mapped so that they allocate  
into the minicache and only replace data from the same structure.  
1-6  
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Introduction  
1.4.6  
1.4.7  
Write Buffer  
The SA-1100 has an eight-entry write buffer with each entry able to contain 1 to 16 bytes. A drain  
write buffer operation is supported.  
Read Buffer  
The SA-1100 has a four-entry read buffer capable of loading 1, 4, or 8 words of data per entry. This  
facility permits software to preload data into the buffer for use at a later time without blocking the  
operation of the processor. Software can flush either a single entry or the entire buffer (four  
entries). The read buffer is controlled through system control coprocessor 15 and can be enabled  
for use in user mode.  
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Functional Description  
2
This chapter provides a functional description of the Intel® StrongARM® SA-1100 Microprocessor  
(SA-1100). It describes the basic building blocks within the processor, lists and describes the pins,  
and explains the memory map.  
2.1  
Block Diagram  
The SA-1100 consists of the following functional blocks:  
Processor  
The processor is the ARM™ SA-1 core with a 16 Kbyte instruction and 8 Kbyte data cache  
(Dcache). The instruction (I) and data (D) streams are translated through independent  
memory-management units (MMUs). Stores are made using a four-line write buffer. The  
performance of specialized load routines is enhanced with the four-entry read buffer that can be  
used to prefetch data for use at a later time. A 16-entry minicache provides a smaller and logically  
separate data cache that can be used to enhance caching performance when dealing with large data  
structures.  
Memory and PCMCIA controller  
The memory and PCMCIA control module (MPCM) supports four banks of standard or EDO DRAM  
on a 32-bit data width. ROM (standard and burst), Flash memory, and SRAM are also supported.  
ROM and Flash can be either 16 or 32 bits wide. SRAM width is limited to 32 bits. Expansion devices  
are supported through PCMCIA control signals that share the memory bus data and address lines to  
complete the card interface. Some external glue logic (buffers and transceivers) is necessary to  
implement the interface. Control is provided to permit two card slots with hot-swap capability.  
Peripherals  
The peripheral control module (PCM) contains a number of serial control devices, an LCD  
controller as well as a six-channel DMA controller to provide service to these devices:  
– An LCD controller with support for passive or active displays  
– A universal serial bus (USB) endpoint controller  
– An SDLC communications controller  
– A serial controller with supporting 115 Kbps and 4 Mbps IrDA protocols  
– A 16550-like UART supporting 230 Kbps  
– A CODEC interface supporting SPI, µWire, TI, UCB1100, and UCB1200  
General system control functions  
The system control module (SCM) is also connected to the peripheral bus. It contains five blocks  
used for general system functions:  
– A real-time clock (RTC) clocked from an independent 32.768 kHz oscillator  
– An operating system timer (OST) for general system timer functions as well as a watchdog mode  
– Twenty-eight general-purpose I/Os (GPIO)  
– An interrupt controller  
– A power-management controller that handles the transitions in and out of sleep and idle modes  
– A reset controller that handles the various reset sources on the processor  
SA-1100 Developer’s Manual  
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Functional Description  
Figure 2-1 shows the functional blocks contained in the SA-1100 integrated processor. Figure 2-2  
is a functional diagram of the SA-1100.  
Figure 2-1. SA-1100 Block Diagram  
Intel®  
StrongARM®  
SA-1100  
Instruction  
*
PC  
Icache  
3.686  
MHz  
PLL  
OSC  
OSC  
JTAG  
and  
Misc  
Test  
IMMU  
(16 Kbytes)  
ARM™*  
SA-1  
Core  
Dcache  
(8 Kbytes)  
Addr  
32.768  
KHz  
DMMU  
Minicache  
RTC  
Load/Store Data  
Processing  
Core  
OS Timer  
General-  
Purpose I/O  
Write  
Read  
Buffer  
Buffer  
Interrupt  
Controller  
Memory  
and  
PCMCIA  
Control  
Module  
(MPCM)  
Power  
Management  
System  
Control  
Module  
(SCM)  
System Bus  
Reset  
Controller  
LCD  
Controller  
DMA  
Controller  
Bridge  
Peripheral Control  
Module (PCM)  
Peripheral Bus  
Serial  
Channel 0  
UjSB  
Serial  
Channel 1  
SDLC  
Serial  
Channel 2  
IrDA  
Serial  
Channel 3  
UART  
Serial  
Channel 4  
CODEC  
* ARM is a trademark and StrongARM is a registered trademark of ARM Limited.  
A6832-01  
2-2  
SA-1100 Developer’s Manual  
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Functional Description  
2.2  
Inputs/Outputs  
Figure 2-2. SA-1100 Functional Diagram  
UDC-  
Serial  
L_DD(7:0)  
L_FCLK  
L_LCLK  
L_PCLK  
L_BIAS  
Channel 0  
(USB)  
UDC+  
RXD _1  
TXD_1  
LCD  
Control  
Serial  
Channel 1  
(SDLC)  
RXD _2  
TXD _2  
Serial  
Channel 2  
(IrDA)  
®
Intel  
GP(27:0)  
GPIO  
Ports  
RXD _3  
TXD _3  
®*  
Serial  
Channel 3  
(UART)  
StrongARM  
SA-1100  
nCAS(3:0)  
nRAS/(3:0)  
nOE  
TXD _C  
RXD _C  
[208-pins]  
Memory  
Control  
Serial  
Channel 4  
(CODEC)  
nWE  
SCLK _C  
SFRM _C  
nCS(3:0)  
BATT_FAULT  
VDD_FAULT  
PWR_EN  
nPOE  
Power  
Management  
nPWE  
nPIOR  
TCK_BYP  
nPIOW  
TESTCLK  
PEXTAL  
PCMCIA  
Bus  
Signals  
nPCE<2:1>  
PSKTSEL  
nPREG  
nPWAIT  
nIOIS16  
PXTAL  
Clocks, Reset  
and Test  
TEXTAL  
TXTAL  
nRESET  
nRESET_OUT  
ROM_SEL  
Address  
Bus  
A<25:0>  
Data Bus  
TCK  
TDI  
D<31:0>  
VDD  
TDO  
TMS  
JTAG  
VDDX  
Supply  
VSS/VSSX  
nTRST  
* StrongARM is a registered trademark of ARM Limited.  
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Functional Description  
2.3  
Signal Description  
The following table describes the signals.  
Key to Signal Types: n – Active low signal  
IC – Input, CMOS threshold  
ICOCZ – Input, CMOS threshold, output CMOS levels, tristatable  
OCZ – Output, CMOS levels, tristatable  
Table 2-1.  
Signal Descriptions (Sheet 1 of 3)  
Name  
A<25:0>  
Type  
OCZ  
Description  
Memory address bus. This bus signals the address requested for memory  
accesses.  
Bits 21..10 carry the 12-bit DRAM address, the static memory devices, and the  
expansion bus receive address bits 25..0.  
D<31:0>  
ICOCZ  
OCZ  
Memory data bus.  
nCS<3:0>  
Static chip selects. These signals are chip selects to static memory devices such  
as ROM and Flash. They are individually programmable in the memory  
configuration registers.  
nOE  
nWE  
OCZ  
OCZ  
Memory output enable. This signal should be connected to the output enables to  
begin driving data onto the data bus.  
DRAM write enable. This signal should be connected to the DRAM write enables  
to perform writes. This signal is used in conjunction with CAS<3:0> to perform  
byte writes.  
nRAS<3:0>  
nCAS<3:0>  
nPOE  
OCZ  
OCZ  
OCZ  
OCZ  
OCZ  
OCZ  
OCZ  
IC  
DRAM RAS. These signals should be connected to the DRAM row address strobe  
(RAS) pin.  
DRAM CAS. These signals should be connected to the DRAM column address  
strobe (CAS) pins.  
PCMCIA output enable. This PCMCIA signal is an output and is used to perform  
reads from memory and attribute space.  
nPWE  
PCMCIA write enable. This signal is an output and is used to perform writes to  
memory and attribute space.  
nPIOW  
PCMCIA I/O write. This signal is an output and is used to perform write  
transactions to the PCMCIA I/O space.  
nPIOR  
PCMCIA I/O read. This signal is an output and is used to perform read  
transactions from the PCMCIA I/O space.  
nPCE<2:1>  
nIOIS16  
nPWAIT  
PSKTSEL  
PCMCIA card enable. These signals are output and are used to select a PCMCIA  
card. Bit one enables the high-byte lane and bit zero enables the low-byte lane.  
I/O Select 16. This signal is an input and is an acknowledgment from the PCMCIA  
card that the current address is a valid 16-bit wide I/O address.  
IC  
PCMCIA wait. This signal is an input and is driven low by the PCMCIA card to  
extend the length of the transfers to/from the SA-1100.  
OCZ  
PCMCIA socket select. This signal is an output and is used by external steering  
logic to route control, address, and data signals to one of the PCMCIA sockets.  
When PSKTSEL is low, socket zero is selected. When PSKTSEL is high, socket  
one is selected. This signal has the same timing as the address lines.  
nPREG  
OCZ  
OCZ  
PCMCIA register select. This signal is an output and indicates that, on a memory  
transaction, the target address is attribute space. This signal has the same timing  
as address.  
L_DD<7:0>  
LCD controller display data.  
2-4  
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Functional Description  
Table 2-1.  
Signal Descriptions (Sheet 2 of 3)  
Name  
L_FCLK  
Type  
OCZ  
Description  
LCD frame clock.  
LCD line clock.  
L_LCLK  
L_PCLK  
L_BIAS  
TXD_C  
RXD_C  
SCLK_C  
SFRM_C  
UDC+  
OCZ  
OCZ  
OCZ  
OCZ  
IC  
LCD pixel clock.  
LCD ac bias drive.  
CODEC transmit.  
CODEC receive.  
CODEC clock.  
OCZ  
OCZ  
OCZ  
IC  
CODEC frame signal.  
Serial port zero transmit pin (UDC).  
Serial port zero receive pin (UDC).  
Serial port one transmit pin (SDLC).  
Serial port one receive pin (SDLC).  
Serial port two transmit pin (IrDA).  
Serial port two receive pin (IrDA).  
Serial port three transmit pin (UART).  
Serial port three receive pin (UART).  
General-purpose input output.  
UDC-  
TXD_1  
OCZ  
IC  
RXD_1  
TXD_2  
OCZ  
IC  
RXD_2  
TXD_3  
OCZ  
IC  
RXD_3  
GP<27:0>  
ROM_SEL  
ICOCZ  
IC  
ROM select. This pin is used to configure the ROM width. It is either grounded or  
pulled high. If ROM_SEL is grounded, the ROM width is 16 bits. If ROM_SEL is  
pulled up, the ROM width is 32 bits.  
PXTAL  
IC  
Input connection for 3.686-MHz crystal.  
Output connection for 3.686-MHz crystal.  
Input connection for 32.768-kHz crystal.  
Output connection for 32.768-kHz crystal.  
PEXTAL  
TXTAL  
OCZ  
IC  
TEXTAL  
PWR_EN  
OCZ  
OCZ  
Power enable. Active high. PWR_EN enables the external power supply.  
Negating it signals the power supply that the system is going into sleep mode and  
that the VDD power supply should be removed.  
BATT_FAULT  
VDD_FAULT  
nRESET  
IC  
IC  
IC  
Battery fault. Signals the SA-1100 that the main power source is going away  
(battery is low or has been removed from the system). The assertion of  
BATT_FAULT causes the SA-1100 to enter sleep mode. The SA-1100 will not  
recognize a wake-up event while this signal is asserted.  
VDD fault. Signals the SA-1100 that the main power supply is going out of  
regulation (shorted card is inserted). VDD_FAULT will cause the SA-1100 to enter  
sleep mode. VDD_FAULT is ignored after a wake-up event until the poser supply  
timer completes (approximately 10 ms).  
Hard reset. This active low signal is a level-sensitive input used to start the  
processor from a known address. A low level will cause the current instruction to  
terminate abnormally, and the on-chip caches, MMU, and write buffer to be  
disabled.  
When nRESET is driven high, the processor will restart from address 0. nRESET  
must remain low until the power supply is stable and the internal 3.686-MHz  
oscillator has come up to speed. While nRESET is low, the processor will perform  
idle cycles.  
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Functional Description  
Table 2-1.  
Signal Descriptions (Sheet 3 of 3)  
Name  
Type  
Description  
nRESET_OUT OCZ  
Reset out. This signal is asserted when nRESET is asserted and deasserts when  
the processor has completed resetting. nRESET_OUT is also asserted for "soft"  
reset events (sleep and watchdog).  
nTRST  
IC  
Test interface reset. Note this pin has an internal pull-down resistor and must be  
driven high to enable the JTAG circuitry. If left unconnected, this pin is pulled low  
and disables JTAG operation.  
TDI  
IC  
JTAG test interface data input. Note this pin has an internal pull-up resistor.  
TDO  
OCZ  
JTAG test interface data output. Note this pin does not have an internal pull-up  
resistor.  
TMS  
TCK  
IC  
IC  
JTAG test interface mode select. Note this pin has an internal pull-up resistor.  
JTAG test interface reference clock. This times all the transfers on the JTAG test  
interface. Note this pin has an internal pull-down resistor.  
TCK_BYP  
TESTCLK  
VDD  
IC  
IC  
Test clock PLL bypass. When TCK_BYP is high, the TESTCLK is used as the  
core clock in place of the PLL clock; when low, the internal PLL output is used.  
This signal has no relation to the JTAG TCK pin.  
Test clock. TESTCLK is used to provide the core clock when TCK_BYP is high. It  
should be tied low if TCK_BYP is low. This pin should be used for test purposes  
only. An end user should ground this pin.  
Positive supply for the core. Nine pins are allocated to this supply; eight pins are  
labeled VDD. The ninth pin, labeled VDDP is dedicated to the PLL supply and  
should be tied directly to the VDD power plane with the other eight VDD pins.  
VDDX  
Positive supply for the pins. Twenty pins are allocated to VDDX, labeled VDDX1,  
VDDX2 and VDDX3. All of these pins should be tied directly to the VDDX power  
plane.  
VSS  
Ground supply. Nine pins are allocated to VSS, including one for the PLL.  
Ground supply for the I/O pins. Eighteen pins are allocated to VSSX.  
VSSX  
2-6  
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Functional Description  
2.4  
Memory Map  
Figure 2-3 shows the SA-1100 memory map. The map is divided into four main partitions of  
1 Gbyte each.  
The bottom partition is dedicated to static memory devices (ROM, SRAM, and Flash) and to the  
PCMCIA expansion bus area. It occupies addresses 0h0000 0000 through 0h3FFF FFFF. This  
space is divided into four 128 Mbyte blocks for static memory devices and two 256 Mbyte blocks  
for PCMCIA.  
The static memory space is intended for ROM, SRAM, and Flash memory. The bottom partition (at  
0h0000 0000) is assumed to be ROM at boot time. The width of the boot ROM is determined by  
the state of the ROMSEL pin. The PCMCIA interface is divided into Socket 0 and Socket 1 space.  
These partitions are further subdivided into I/O, memory and attribute space.  
The next partition (0h4000 0000 to 0h7FFF FFFF) is reserved. Accessing this reserved space  
results in a data abort exception.  
The third partition (0h8000 0000 to 0hBFFF FFFF) contains all on-chip registers (except those  
specified by the ARM V4 architecture). This block is further subdivided into four blocks of  
256 Mbyte each. They contain control registers for the major functional blocks within the  
processor (MECM, SCM, PCM). The LCD and DMA controllers are separate from the rest of the  
PCM and occupy the top 256 Mbyte partition.  
The fourth partition (0hC000 0000 to 0hFFFF FFFF) contains DRAM memory. The bank sizes for  
DRAM are fixed at 128 Mbyte each. With multiple banks implemented, there probably will be  
gaps in the map that should be mapped through the memory-management unit. The next 128 Mbyte  
block in this partition is mapped within the memory controller and returns zeros when read. This  
function is intended to facilitate rapid cache flushing by not requiring an external memory access to  
load data into the cache. This space is burstable. Writes to this space have no effect. The top  
384 Mbyte of this partition is reserved. Accessing this space causes a data abort exception.  
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Functional Description  
Figure 2-3. SA-1100 Memory Map  
Reserved (384 Mbyte)  
Cache flush replacement data  
Reads return zero  
128 Mbyte  
Zeros Bank (128 Mbyte)  
DRAM Bank 3 (128 Mbyte)  
DRAM Bank 2 (128 Mbyte)  
DRAM Bank 1 (128 Mbyte)  
DRAM Bank 0 (128 Mbyte)  
Dynamic Memory  
512 Mbyte  
0hC000 0000  
LCD and DMA Registers (256 Mbyte)  
Memory and Expansion Registers (256 Mbyte)  
System Control Module Registers(256 Mbyte)  
Peripheral Module Registers (256 Mbyte)  
Internal Registers  
1GB  
0h8000 0000  
0h4000 0000  
Reserved (1GB)  
PCMCIA Socket 0 Space (256 Mbyte)  
PCMCIA Socket 1 Space (256 Mbyte)  
PCMCIA Interface  
512 Mbyte  
0h2000 0000  
0h0000 0000  
Static Bank Select 3 (128 Mbyte)  
Static Bank Select 2 (128 Mbyte)  
Static Bank Select 1 (128 Mbyte)  
Static Bank Select 0 (128 Mbyte)  
Static Memory  
(ROM, Flash, SRAM)  
512 Mbyte  
2-8  
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ARMImplementation Options  
3
The following sections describe ARM™ architecture options that are implemented by the  
Intel® StrongARM® SA-1100 Microprocessor (SA-1100).  
3.1  
Big and Little Endian  
The big endian bit in the control register sets whether the SA-1100 treats words stored in memory  
as being stored in big endian or little endian format. Memory is viewed as a linear collection of  
bytes numbered upwards from 0. Bytes 0 to 3 hold the first stored word, bytes 4 to 7 hold the  
second, and so on.  
In the little endian scheme, the lowest numbered byte in a word is considered to be the least  
significant byte of the word and the highest numbered byte is the most significant. Byte 0 of the  
memory system should be connected to data lines 7 through 0 (D<7:0>) in this scheme.  
In the big endian scheme, the most significant byte of a word is stored at the lowest numbered byte  
and the least significant byte is stored at the highest numbered byte. Therefore, byte 0 of the  
memory system should be connected to data lines 31 through 24 (D<31:24>).  
The state of the big endian bit changes the location of the bytes only within a 32-bit word. The  
accessed bytes are changed for the load byte, store byte, load halfword, and store halfword  
instructions only. Instruction fetches and word load and stores are not changed by the state of the  
big endian bit, except when those accesses are performed with memory on 16-bit data busses. See  
Chapter 10 for details on configuring bus widths for various memory types.  
These conventions are identical to those of the SA-110. In addition, the SA-1100 DMA controller  
is programmable by channel as to the endian format of the transfer. For DMA transfers, all  
memory accesses are words. Then the data is buffered and transferred to/from the device as  
halfwords or bytes. When the words are assembled or disassembled, the endian format of the  
channel is observed. For details on how DMA data is transferred relative to the endian format of  
3.2  
Exceptions  
Exceptions arise whenever there is a need for the normal flow of program execution to be broken;  
for example, so that the processor can be diverted to handle an interrupt from a peripheral. The  
processor state just prior to handling the exception must be preserved so that the original program  
resumes when the exception routine has completed. Many exceptions may arise at the same time.  
The SA-1100 handles exceptions by making use of banked registers to save state. The contents of  
PC and CPSR are copied into the appropriate R14 and SPSR, and the PC and mode bits in the  
CPSR bits are forced to a value that depends on the exception. Interrupt disable flags are set where  
required to prevent otherwise unmanageable nestings of exceptions. In the case of a reentrant  
interrupt handler, R14 and the SPSR should be saved onto a stack in main memory before  
reenabling the interrupt; when transferring the SPSR register to and from a stack, it is important to  
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ARM™ Implementation Options  
transfer the whole 32-bit value, and not just the flag or control fields. When multiple exceptions  
arise simultaneously, a fixed priority determines the order in which they are handled. The priorities  
are listed later in this chapter. Most exceptions are fully defined in the ARM Architectural  
Reference. The following sections specify the exceptions where the SA-1100 implementation  
differs from the ARM Architectural Reference.  
SA-1100 initiates all exceptions in 32-bit mode. When an exception occurs while running in 26-bit  
mode, the SA-1100 saves only the PC in R14 and the CPSR in the SPSR of the exception mode.  
The 32-bit handler must merge the condition codes, the interrupt enables, and the mode from the  
SPSR into R14 if a handler is to run in 26-bit mode.  
3.2.1  
Power-Up Reset  
When the nRESET signal is low, SA-1100 stops executing instructions, asserts the nRESET_OUT  
pin, and then performs idle cycles on the bus.  
When nRESET is high again, SA-1100 does the following:  
1. Overwrites R14_svc and SPSR_svc by copying the current values of the PC and CPSR into  
them. The values of the saved PC and CPSR are not defined.  
2. Forces M<4:0>=10011 (32-bit supervisor mode) and sets the I and F bits in the CPSR.  
3. Forces the PC to fetch the next instruction from address 0x0000 0000.  
4. Based on the state of the ROM_SEL pin, fetches this first instruction from either 16-bit  
(ROM_SEL low) or 32-bit (ROM_SEL high) space. The SA-1100 memory controller  
assembles the data into words in the case of a 16-bit wide ROM.  
At the end of the reset sequence, the MMU, Icache, Dcache, and write buffer are disabled.  
Alignment faults are also disabled, and little-endian mode is enabled. During power-up, nRESET  
must be negated no earlier than 150 milliseconds after VDD and VDDx are stable to allow the  
internal 3.686-MHz oscillator to stabilize. After the negation of nRESET, the PLL begins its  
internally timed locking sequence. Note that the assertion of nRESET is destructive because the  
state of the real-time clock and the contents of DRAM are lost.  
The SA-1100 has three types of reset. See Section 16.2, “Reset” on page 16-2 in the  
Boundary-Scan Test Interface for details.  
3.2.2  
ROM Size Select  
The ROM width may be selected using the ROM_SEL pin. This pin is sampled during the assertion  
of nRESET. The value is stored in the memory controller for use during ROM accesses. If this  
signal is high during RESET, then the ROM is selected to be 32 bits wide. If it is low during  
RESET, then the ROM width is 16 bits. There is no provision for 8-bit ROMs in the SA-1100.  
3-2  
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3.2.3  
Abort  
An abort can be signalled by the internal memory-management unit, through a data breakpoint, or  
by a reference to reserved memory. An abort indicates that the current memory access cannot be  
completed or that a prespecified breakpoint address and (optionally) data pattern has been reached.  
For instance, in a virtual memory system, the data corresponding to the current address may have  
been moved out of memory onto a disk, and considerable processor activity may be required to  
recover the data before the access can be performed successfully. The SA-1100 checks for an abort  
during memory access cycles. When aborted, the SA-1100 responds in one of two ways:  
1. If the abort occurred during an instruction prefetch (a prefetch abort), the prefetched  
instruction is marked as invalid but the abort exception does not occur immediately. If the  
instruction is not executed, for example, as a result of a branch being taken while it is in the  
pipeline, no abort will occur. An abort will take place if the instruction reaches the head of the  
pipeline and is about to be executed.  
2. If the abort occurred during a data access (a data abort), the action depends on the instruction  
type.  
a. Single data transfer instructions (LDR, STR) will abort with no registers modified.  
b. The swap instruction (SWP) is aborted as though it had not executed, though externally  
the read access may take place.  
c. Block data transfer instructions (LDM, STM) abort on the first access that cannot  
complete. If write-back is set, the base is NOT updated. If the instruction would normally  
have overwritten the base with data (for example, an LDM instruction with the base in the  
transfer list), the original value in the base register is restored.  
When either a prefetch or data abort occurs, the SA-1100 performs the following:  
1. Saves the address of the aborted instruction plus 4 (for prefetch aborts) or 8 (for data aborts) in  
R14_abt; saves CPSR in SPSR_abt.  
2. Forces M<4:0>=10111 (abort mode) and sets the I bit in the CPSR.  
3. Forces the PC to fetch the next instruction from either address 0x0C (prefetch abort) or address  
0x10 (data abort).  
To return after fixing the reason for the abort, use SUBS PC,R14_abt,#4 (for a prefetch abort) or  
SUBS PC,R14_abt,#8 (for a data abort). This will restore both the PC and the CPSR, and retry the  
aborted instruction.  
The abort mechanism allows a demand paged virtual memory system to be implemented when  
suitable memory management software is available. The processor is allowed to generate arbitrary  
addresses, and when the data at an address is unavailable, the MMU signals an abort. The processor  
traps into system software, which must work out the cause of the abort, make the requested data  
available, and retry the aborted instruction. The application program needs no knowledge of the  
amount of memory available to it, nor is its state in any way affected by the abort.  
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ARM™ Implementation Options  
3.2.4  
Vector Summary  
Table 3-1 lists byte addresses, and they normally contain branch instructions pointing to the  
relevant routines. These addresses (except the reset vector) can be changed (to 0xFFFF xxxx)  
through the vector adjust facility (bit 13, register 1, coprocessor 15). The vector adjust is cleared at  
reset and cannot modify the reset vector.  
Table 3-1.  
Vector Summary  
Address  
Exception  
Mode on Entry  
Supervisor  
0x00000000  
0x00000004  
0x00000008  
0x0000000C  
0x00000010  
0x00000014  
0x00000018  
0x0000001C  
Reset  
Undefined instruction  
Software interrupt  
Abort (prefetch)  
Abort (data)  
Not used  
Undefined  
Supervisor  
Abort  
Abort  
IRQ  
IRQ  
FIQ  
FIQ  
3.2.5  
Exception Priorities  
When multiple exceptions arise at the same time, a fixed priority system determines the order in  
which they will be handled:  
1. Reset (highest priority)  
2. Data abort  
3. FIQ  
4. IRQ  
5. Prefetch abort  
6. Undefined instruction, software interrupt (lowest priority)  
Note that not all exceptions can occur at once. Undefined instructions and software interrupts are  
mutually exclusive because they correspond to particular (nonoverlapping) decodings of the  
current instruction.  
If a data abort occurs at the same time as a FIQ, and FIQs are enabled (that is, the F flag in the  
CPSR is clear), the SA-1100 will enter the data abort handler and then immediately proceed to the  
FIQ vector. A normal return from FIQ will cause the data abort handler to resume execution.  
Placing data abort at a higher priority than FIQ is necessary to ensure that the transfer error does  
not escape detection; the time for this exception entry should be added to worst-case FIQ latency  
calculations.  
3-4  
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ARM™ Implementation Options  
3.2.6  
Interrupt Latencies and Enable Timing  
The ability to recognize an IRQ or FIQ interrupt is, in part, determined by the I and F bits of the  
CPSR. To ensure that a pending interrupt is taken, an interrupt-enabling write to CPSR (msr  
instruction) must be separated from an interrupt-disabling write to the CPSR by at least two  
instructions.  
3.3  
Coprocessors  
The SA-1100 has no external coprocessor bus, so it is not possible to add external coprocessors to  
this device.  
The SA-1100 uses the internal coprocessor designated 15 for control of the on-chip MMU, caches,  
clocks, and breakpoints. Coprocessor 15 is also used for read-buffer fills and flushes. If a  
coprocessor other than 15 is used, then the SA-1100 will take the undefined instruction trap. The  
coprocessor load, store, and data operation instructions also take the undefined instruction trap.  
Permissions are set so that access to coprocessor 15 is privileged except where protection is  
programmable with respect to the read buffer operations.  
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Instruction Set  
4
This section describes the instruction timing for the Intel® StrongARM® SA-1100 Microprocessor  
(SA-1100).  
4.1  
4.2  
Instruction Set  
The SA-1100 implements the ARMV4 architecture as defined in the ARM Architecture  
Reference, 28-July-1995, with previously noted options and additions.  
Instruction Timings  
Table 4-1 lists the instruction timing for the SA-1100. The result delay is the number of cycles that  
the next sequential instruction would stall if it used the result as an input. The issue cycles are the  
number of cycles that this instruction takes to issue. For most instructions, the result delay is zero  
and the issue cycles is one. For load and stores, the timing is for cache hits.  
Table 4-1.  
Instruction Timings  
Instruction Group  
Data processing  
Result Delay  
Issue Cycles  
0
1..3  
1..3  
0
1
Mul or Mul/Add giving 32-bit result  
Mul or Mul/Add giving 64-bit result  
Load single – write-back of base  
Load single – load data zero extended  
Load single – load data sign extended  
Store single – write-back of base  
1
2
1
1
1
2
1
0
1
MAX  
Load multiple (delay for last register)  
Store multiple – write-back of base  
1
0
(2, number of registers loaded)  
MAX  
(2, number of registers loaded)  
Branch or branch and link  
0
2
1
0
0
2
1
1
1
3
1
2
MCR  
MRC  
MSR to control  
MRS  
Swap  
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Coprocessors  
5
The operation and configuration of the Intel® StrongARM® SA-1100 Microprocessor (SA-1100) is  
controlled with coprocessor instructions, configuration pins, and memory-management page  
tables. The coprocessor 15 instructions manipulate on-chip registers that control the configuration  
of the cache, write buffer, MMU, read buffer, breakpoints, and other configuration options.  
Note: The gray areas in the register and translation diagrams are reserved and should be programmed 0  
for future compatibility.  
5.1  
Internal Coprocessor Instructions  
The on-chip cache, MMU, write buffer, and read buffers are controlled using MRC instructions and  
MCR instructions. These operations to coprocessor 15 are allowed only in nonuser modes except  
when read-buffer operations are explicitly enabled. The undefined instruction trap is taken if  
accesses are attempted in user mode. Figure 5-1 shows the format of internal coprocessor  
instructions MRC and MCR.  
Figure 5-1. Format of Internal Coprocessor Instructions MRC and MCR  
31  
28 27  
24 23  
21 20 19  
16 15  
12 11  
8
7
5
4
3
0
OPC_2  
CRm  
1
1
1
0
n
1
1
1
1
1
CRn  
Rd  
Cond  
Cond  
ARM™ condition codes  
1 MRC register read  
0 MCR register write  
SA-1100 register  
n
CRn  
Rd  
ARM register  
OPC_2  
CRm  
Function bits for some MRC/MCR instructions  
Function bits for some MRC/MCR instructions  
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5.2  
Coprocessor 15 Definition  
The SA-1100 coprocessor 15 contains registers that control the cache, MMU, and write buffer  
operation as well as some clocking functions. These registers are accessed using CPRT instructions  
to coprocessor 15 with the processor in any privileged mode. Only some of registers 0–15 are  
valid; the result of an access to an invalid register is unpredictable. Table 5-1 lists the coprocessor  
15 control registers.  
Table 5-1.  
Cache and MMU Control Registers (Coprocessor 15)  
Register  
Register Reads  
Register Writes  
0
1
2
3
4
5
6
7
8
9
ID  
RESERVED  
Control  
Control  
Translation table base  
Domain access control  
RESERVED  
Translation table base  
Domain access control  
RESERVED  
Fault status  
Fault status  
Fault address  
Fault address  
RESERVED  
Cache operations  
TLB operations  
RESERVED  
RESERVED  
Read buffer operations  
RESERVED  
10..12  
13  
RESERVED  
Read process ID (PID)  
Read breakpoint  
RESERVED  
Write process ID (PID)  
Write breakpoint  
Test, clock, and idle  
14  
15  
5.2.1  
Register 0 – ID  
Register 0 is a read-only register that returns an architecture and implementation-defined  
identification for the device.identification for the device.  
31  
24 23  
16 15  
4
3
0
Part Number  
44  
Architecture Version  
Stepping  
ARM architecture version  
01 = Version 4  
Architecture Version  
Part Number  
Stepping  
Part number  
A11 = SA1100  
Stepping revision of SA-1100  
1 = B stepping  
2 = C stepping  
8 = D stepping  
9 = E stepping  
11 = G stepping  
5-2  
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5.2.2  
Register 1 – Control  
Register 1 is a read/write register containing control bits. All writable bits in this register are forced  
low by reset. The shaded bits (also labeled r) are reserved and are not readable or writable.  
13  
31  
12  
9
8
7
6
5
4
3
2
1
0
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r X  
I
r
r
R S B 1 1 1 W C A M  
M bit 0  
A bit 1  
C bit 2  
W bit 3  
B bit 7  
S bit 8  
R bit 9  
I bit 12  
Enable/disable  
0 – On-chip memory-management unit disabled  
1 – On-chip memory-management unit enabled  
Address fault enable/disable  
0 – Alignment fault disabled  
1 – Alignment fault enabled  
Data cache enable/disable  
0 – Data cache disabled  
1 – Data cache enabled  
Write buffer enable/disable  
0 – Write buffer disabled  
1 – Write buffer enabled  
Big/little endian  
0 – Little endian operation  
1 – Big endian operation  
System  
This bit selects the access checks performed by the memory-management unit.  
See the ARM Architecture Reference for more information.  
ROM  
This bit selects the access checks performed by the memory-management unit.  
See the ARM Architecture Reference for more information.  
Instruction cache enable/disable  
0 – Instruction cache disabled  
1 – Instruction cache enabled  
X bit 13  
Virtual interrupt vector adjust  
0 – Base address of interrupt vectors is 0h0000 0000  
1 – Base address of interrupt vectors is 0hFFFF 0000  
Bits 14..31  
Unused.  
Undefined on Read. Writes ignored.  
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5.2.3  
Register 2 – Translation Table Base  
Register 2 is a read/write register that holds the base of the currently active level 1 page table. Bits  
<13:0> are undefined on read, ignored on write.  
31  
14 13  
0
Translation Table Base  
5.2.4  
Register 3 – Domain Access Control  
Register 3 is a read/write register that holds the current access control for domains 0 to 15. Refer to  
the ARM Architecture Reference for a description of the domain structure  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  
15 14 13 12 11 10  
9
8
7
6
5
4
3
2
1
0
9
8
7
6
5
4
3
2
1
0
5.2.5  
5.2.6  
Register 4 – RESERVED  
Register 4 is reserved. Accessing this register yields unpredictable results.  
Register 5 – Fault Status  
Reading register 5 returns the current contents of the fault status register (FSR). The FSR is written  
when a data memory fault occurs or can be written by an MCR to the FSR. It is not updated for a  
prefetch fault. See Chapter 7, “Memory-Management Unit (MMU)” for more details. Bits  
<31:10> are undefined on read, ignored on write. Bit 9 is set when a data breakpoint is taken and  
can be cleared by an MCR operation. Bit 8 is ignored on write and is always returned as zero.  
Refer to the ARM Architecture Reference for a description of the domain and status fields.  
31  
10  
9
8
7
4
3
0
D 0  
Domain  
Status  
5.2.7  
Register 6 – Fault Address  
Reading register 6 returns the current contents of the fault address register (FAR). The FAR is  
written when a data memory fault occurs with the virtual address of the data fault or can be written  
by an MCR to the FAR.  
31  
0
Fault Virtual Address  
5-4  
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5.2.8  
Register 7 – Cache Control Operations  
Register 7 is a write-only register. The CRm and OPC_2 fields are used to encode the cache control  
operations. Operation for all other values for OPC_2 and CRm is unpredictable.  
Function  
Flush I+D  
OPC_2  
0b000  
CRm  
0b0111  
Data  
Ignored  
Flush I  
0b000  
0b000  
0b001  
0b001  
0b100  
0b0101  
0b0110  
0b0110  
0b1010  
0b1010  
Ignored  
Flush D  
Ignored  
Flush D single entry  
Clean Dcache entry  
Drain write buffer  
Virtual address  
Virtual address  
Ignored  
5.2.9  
Register 8 – TLB Operations  
Register 8 is a write-only register. The CRm and OPC_2 fields are used to encode the following  
TLB flush operations. Operation for all other values of OPC_2 and CRm is unpredictable.  
Function  
OPC_2  
0b000  
CRm  
0b0111  
Data  
Flush I+D  
Flush I  
Ignored  
Ignored  
Ignored  
0b000  
0b000  
0b001  
0b0101  
0b0110  
0b0110  
Flush D  
Flush D single entry  
Virtual address  
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5.2.10  
Register 9 – Read-Buffer Operations  
The read buffer is controlled and accessed through register 9 of coprocessor 15. The functions  
supported are: flush-all buffers, flush-a-single entry, load-an-entry (1, 4 or 8 words), and  
enable/disable user mode access.  
The CRm and OPC_2 fields are used to encode these control operations. All other values for  
OPC_2 and CRm are undefined and the results of using them are unpredictable.  
Function  
OPC_2  
0b000  
CRm  
0b0000  
Data  
Flush all entries  
Flush Buffer 0  
Flush Buffer 1  
Flush Buffer 2  
Flush Buffer 3  
Ignored  
Ignored  
Ignored  
Ignored  
Ignored  
0b001  
0b001  
0b001  
0b001  
0b010  
0b010  
0b010  
0b010  
0b010  
0b010  
0b010  
0b010  
0b010  
0b010  
0b010  
0b010  
0b100  
0b101  
0b0000  
0b0001  
0b0010  
0b0011  
0b0000  
0b0100  
0b1000  
0b0001  
0b0101  
0b1001  
0b0010  
0b0110  
0b1010  
0b0011  
0b0111  
0b1011  
0b0000  
0b0000  
Load Buffer 0 with one word  
Load Buffer 0 with four words  
Load Buffer 0 with eight words  
Load Buffer 1 with one word  
Load Buffer 1 with four words  
Load Buffer 1 with eight words  
Load Buffer 2 with one word  
Load Buffer 2 with four words  
Load Buffer 2 with eight words  
Load Buffer 3 with one word  
Load Buffer 3 with four words  
Load Buffer 3 with eight words  
Disable user-mode MCR access  
Enable user-mode MCR access  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Virtual address  
Ignored  
Ignored  
See Chapter 6, “Caches, Write Buffer, and Read Buffer” for details on the use and operation of the  
read buffer.  
5.2.11  
Registers 10 – 12 RESERVED  
Accessing any of these registers yields unpredictable results.  
5-6  
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5.2.12  
Register 13 – Process ID Virtual Address Mapping  
The SA-1100 supports the remapping of virtual addresses through a process ID (PID) register. The  
6-bit PID value is OR’ed with bits 30..25 of the virtual address when bits 31..25 of the virtual  
address are zero. This effectively remaps the address to one of 64 “slots” in the lower 2 Gbyte  
address space. The following table shows the OPC_2 and CRm field encodings used to access the  
process ID register. This register is zero at reset and if left unmodified, effectively disables the  
remapping function. As such, no explicit enable or disable function is necessary. Reserved bits read  
as zero and must be written as zero. This register is readable and writable.  
Function  
Access process ID register  
OPC_2  
0b000  
CRm  
0b0000  
The following figure shows the format of the process ID register.  
31  
25 24  
0
30  
r
Process ID  
Reserved  
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5.2.13  
Register 14 – Debug Support (Breakpoints)  
The SA-1100 supports address and data breakpoints through register 14 of coprocessor 15. The  
instruction formats follow. For a description of the breakpoint operation, see Chapter 15, “Debug  
Support”. The following table shows the OPC_2 and CRm field encodings used to access the  
address and data breakpoints.  
Function  
OPC_2  
0b000  
CRm  
0b0000  
Access data breakpoint address register (DBAR).  
Access data breakpoint value register (DBVR).  
Access data breakpoint mask register (DBMR).  
0b000  
0b000  
0b000  
0b0001  
0b0010  
0b0011  
Load data breakpoint control register (DBCR).  
-----------------------------------------------------------------  
DBCR Bit  
Action  
-----------------------------------------------------------------  
lw  
0 = Disable load watch  
1 = Enable load watch  
saw  
sdw  
0 = Disable store address watch  
1 = Enable store address watch  
0 = Disable store data watch  
1 = Enable store data watch  
Write instruction breakpoint address and control register (IBCR).  
0b000  
0b1000  
Low-order address bit is the address break enable/disable bit.  
Register not readable.  
The DBCR register is a 3-bit register used to control the enabling and disabling of the data  
breakpoints. Bits 0..2 are valid and positioned as shown below. Bits 3..31 are reserved. These bits  
read as zeros and writes have no effect.  
31  
2
1
0
sdw saw lw  
Reserved  
The IBCR is a write-only register used to load an address breakpoint address and to set an enable  
bit for the function. If an address is loaded with bit 0 (E) set, then the address is enabled as a  
breakpoint. If bit zero is cleared, then the breakpoint is disabled. Bit 1 is reserved and should be  
written to zero.  
31  
0
2
1
r
E
Instruction Address Breakpoint Value  
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5.2.14  
Register 15 – Test, Clock, and Idle Control  
Register 15 is a write-only register. The CRm and OPC_2 fields are used to encode the following  
control operations. Operation for all other values of OPC_2 and CRm is unpredictable.  
Function  
OPC_2  
0b001  
CRm  
Enable odd-word loading of the linear feedback shift  
register ( LFSR)  
0b0001  
Enable even-word loading of LFSR  
Clear LFSR  
0b001  
0b001  
0b001  
0b010  
0b010  
0b010  
0b010  
0b0010  
0b0100  
0b1000  
0b0001  
0b0010  
0b0100  
0b1000  
Move LFSR to R14.abort  
Enable clock switching  
Disable clock switching  
RESERVED  
Wait for interrupt  
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Caches, Write Buffer, and Read Buffer 6  
To reduce effective memory access time, the Intel® StrongARM® SA-1100 Microprocessor  
(SA-1100) has an instruction cache, a data cache, a write buffer, and a read buffer. All except the  
read buffer are transparent to program execution. The following sections describe each of these  
units and give all necessary programming information.  
6.1  
Instruction Cache (Icache)  
The SA-1100 contains a 16 Kbyte instruction cache (Icache). The Icache has 512 lines of 32 bytes  
(8 words), arranged as a 32-way set associative cache, and uses the virtual addresses generated by  
the processor core. The Icache is always reloaded a line at a time (8 words). It may be enabled or  
disabled via the SA-1100 control register, and is disabled on the assertion of nRESET or through a  
software or sleep reset sequence. (See Section 9, “System Control Module” on page 9-1 in the  
System Control Module for details.) The operation of the cache, when memory management is  
enabled, is further controlled by the cacheable or C bit stored in the memory-management page  
table. If memory management is disabled, all addresses are marked as cacheable (C=1). When  
memory management is enabled, the C bit in each page table entry can disable caching for an area  
of virtual memory.  
6.1.1  
Icache Operation  
In the SA-1100, the instruction cache is searched regardless of the state of the C bit; only reads that  
miss the cache are affected. If, on an Icache miss, the C bit is a one or the Memory Management  
Unit (MMU) is disabled, a linefetch of 8 words is performed and it is placed in a cache bank with a  
round-robin replacement algorithm. If, on a miss, the MMU is enabled and the C bit is a zero for  
the given virtual address, an external memory access for a single word is performed and the cache  
is not written.The Icache should be enabled as soon as possible after reset for best performance.  
6.1.2  
Icache Validity  
The Icache operates with virtual addresses, so care must be taken to ensure that its contents remain  
consistent with the virtual-to-physical mappings performed by the memory management unit. If the  
memory mappings are changed, the Icache validity must be ensured. The Icache is not coherent  
with stores to memory, so programs that write cacheable instruction locations must ensure the  
Icache validity. Instruction fetches do not check the write buffer, so data must not only be pushed  
out of the cache but the write buffer must also be drained.  
6.1.2.1  
Software Icache Flush  
The entire Icache can be invalidated by writing to the SA-1100 cache operations register (register  
7). The cache is flushed immediately when the register is written, but note that the following  
instruction fetches may come from the cache before the register is written.  
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6.1.3  
Icache Enable/Disable and Reset  
The Icache is automatically disabled and flushed on the assertion of nRESET. Once enabled,  
cacheable read accesses cause lines to be placed in the cache. If the Icache is subsequently  
disabled, no new lines are placed in the cache, but the cache is still searched and if the data is  
found, it will be used by the processor. If the data in the cache must not be used, then the cache  
must be flushed.  
6.1.3.1  
6.1.3.2  
6.2  
Enabling the Icache  
To enable the Icache, set bit 12 in the control register. The MMU and Icache may be enabled  
simultaneously with a single control register write.  
Disabling the Icache  
To disable the Icache, clear bit 12 in the control register.  
Data Caches (Dcaches)  
The SA-1100 contains two logically separate data caches: the main data cache and the mini data  
cache (or minicache). The main data cache, an 8 Kbyte write-back Dcache, has 256 lines of 32  
bytes (8words) in a 32-way set-associative organization. It is intended for use during most data  
accesses. This cache allocates on loads to spaces marked B=1 and C=1. Replacements in the main  
data cache are selected according to a set of round-robin pointers. At reset, the pointer in each  
block of the Dcache points to way zero of each 32-way block. As lines are allocated, the pointers  
are incremented to the next way of the set. After way 31 is allocated, the next linefill replaces (and  
copies back to memory, if dirty) the data in way zero. The minicache is a 512-byte write-back  
cache. It has 16 lines of 32 bytes (8 words) in a two-way set-associative organization and provides  
an alternate caching structure for dealing with large data structures that could thrash the main data  
cache. This cache allocates on loads to spaces marked B=0 and C=1. Replacements in the  
minicache use the same round-robin pointer mechanism as in the main data cache. However, since  
this cache is only two-way set-associative, the replacement algorithm reduces to a simple  
least-recently-used (LRU) mechanism.  
The Dcaches are accessed in parallel and the design ensures that a particular line entry will exist in  
only one of the two at any time. Both Dcaches use the virtual address generated by the processor  
and allocate only on loads (write misses never allocate in the cache). Each line entry contains the  
physical address of the line and two dirty bits. The dirty bits indicate the status of the first and the  
second halves of the line. When a store hits in the Dcaches, the dirty bit associated with it is set.  
When a line is evicted from the Dcaches, the dirty bits are used to decide if all, half, or none of the  
line will be written back to memory using the physical address stored with the line. The Dcaches  
are always reloaded a line at a time (8 words).  
The Dcaches allocate only on loads and according to the settings of the B and C bits in the MMU.  
If B=0 and C=1, the memory access allocates into the minicache. If B=1 and C=1, the memory  
access allocates into the main data cache. The Dcaches should be flushed prior to changing the  
bufferable and/or cacheable state of the page table mapping.  
The main data cache and the minicache are enabled and disabled via the SA-1100 control register,  
and are disabled on nRESET as well as software, sleep, and watchdog reset. The operation of the  
Dcaches is further controlled by the cacheable or C bit and the bufferable or B bit stored in the  
6-2  
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Caches, Write Buffer, and Read Buffer  
memory-management page table. For this reason, in order to use the Dcaches, the MMU must be  
enabled. The two functions may be enabled simultaneously with a single write to the control  
register.  
Note: The Dcaches operate with virtual addresses, so care must be taken to ensure that their contents  
remain consistent with the virtual-to-physical mappings performed by the memory-management  
unit. If the memory mappings are changed, the validity of the Dcaches must be ensured.  
6.2.1  
Cacheable Bit – C  
The cacheable bit determines whether, on load misses, the data being read should be placed in one  
of the two data caches. Cache hits are not affected by the cacheable bit; if a data access hits in the  
cache, the data is assumed to be valid and the load or store is performed. Typically, main memory is  
marked as cacheable to improve system performance and I/O space as noncacheable to stop the  
data from being stored in SA-1100s cache. For example, if the processor is polling a hardware flag  
in I/O space, it is important that the processor is forced to read data from the external peripheral,  
and not a copy of initial data held in the cache.  
6.2.1.1  
Cacheable Reads – C = 1  
A linefetch of 8 words will be performed and it will be placed in a cache bank with a round-robin  
replacement algorithm.  
6.2.1.2  
Noncacheable Reads – C = 0  
An external memory access will be performed and the cache will not be written.  
6.2.2  
Bufferable Bit – B  
The bufferable bit does not affect writes that hit the Dcaches. If a store hits in the Dcaches, the store  
is assumed to be bufferable. Write-backs of dirty lines are treated as bufferable writes. See the  
Section 6.3, “Write Buffer (WB)” on page 6-5 for more information on the B bit.  
Table 6-1 summarizes the effects of the B and C bits on the Dcaches.  
Table 6-1.  
Effects of the Cacheable and Bufferable Bits on the Data Caches  
Load  
Store  
B
0
C
0
Cache Hit  
Cache Miss  
Cache Hit  
Cache Miss  
Deliver cache data. Load from memory.  
Store to either cache.  
– Mark line dirty.  
Store to memory.  
– No allocate.  
– No allocate.  
0
1
1
1
0
1
Deliver cache data. Allocate to minicache.  
Store to either cache.  
– Mark line dirty.  
Store to memory.  
– No allocate.  
Deliver cache data. Load from memory.  
– No allocate.  
Store to either cache.  
– Mark line dirty.  
Store to memory.  
– No allocate.  
Deliver cache data. Allocate to main data cache. Store to either cache.  
– Mark line dirty.  
Store to memory.  
– No allocate.  
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Caches, Write Buffer, and Read Buffer  
6.2.3  
Software Dcache Flush  
The SA-1100 supports the flush and clean operations on single entries of the Dcaches by writes to  
the cache operations registers. The flush whole cache is also supported. Note that since this is a  
write-back cache, in order to prevent the loss of data, a flush whole must be preceded by a  
sequence of loads to cause the cache to write back any dirty entries. The memory controller in the  
SA-1100 provides an internally decoded memory space to perform coherent Dcache flushing. This  
space resides in the upper 512 megabytes of the memory map (starting at virtual address  
0hE000 0000) and, when accessed, is detected by the memory controller, which then returns zeros  
without incurring an external memory latency.  
The following code causes the main data cache to flush all dirty entries:  
;+  
;Call:  
;
;
;
R0 points to the start of a 8192 byte region of readable data used  
only for this cache flushing routine.  
bl writeBackDC  
;Return:  
;
R0, R1, R2 trashed  
;
Data cache is clean  
;-  
writeBackDC  
movr0, 0hE0000000  
addr1, r0, #8192  
l1  
ldr r2, <r0>, #32  
teqr1, r0  
bnel1  
mcrp15, 0, r0, c7, c6, 0  
movpc, r14  
A similar routine may be written to flush the minicache. To perform this flush, the MMU B and C  
settings must be as described above. The invalidate-all operation also invalidates the minicache.  
6.2.3.1  
Doubly Mapped Space  
Since the Dcaches work with virtual addresses, it is assumed that every virtual address maps to a  
different physical address. If the same physical location is accessed by more than one virtual  
address, the cache cannot maintain consistency, since each virtual address has a separate entry in  
the cache, and only one entry is updated on a processor write operation. To avoid any cache  
inconsistencies, doubly mapped virtual addresses should be marked as noncacheable.  
6.2.4  
Dcaches Enable/Disable and Reset  
The Dcaches are automatically disabled and flushed on the assertion of nRESET. Once enabled,  
cacheable read accesses cause lines to be placed in the Dcaches. If subsequently disabled, no new  
lines are placed in the Dcaches, but they are still searched and if the data is found, it is used by the  
processor. Write operations continue to update the Dcaches, thus maintaining consistency with the  
external memory. If the data in the Dcaches must not be used, then the Dcaches must be flushed.  
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6.2.4.1  
Enabling the Dcaches  
To enable the Dcaches, make sure that the MMU is enabled first by setting bit 0 in the control  
register, then enable the Dcaches by setting bit 2 in the control register. The MMU and Dcaches can  
be enabled simultaneously with a single control register write.  
6.2.4.2  
Disabling the Dcaches  
To disable the Dcache, clear bit 2 in the control register.  
6.3  
Write Buffer (WB)  
The SA-1100 write buffer is used to improve system performance by buffering up to 8 blocks of  
data of 1 to 16 bytes, at independent addresses. It can be enabled or disabled via the W bit (bit 3) in  
the SA-1100 control register. The buffer is disabled and all entries are marked empty following  
reset. Operation of the write buffer is further controlled by the cacheable or C bit and the  
bufferable or B bit, which are stored in the memory-management page tables. For this reason, in  
order to use the write buffer, the MMU must be enabled. The two functions can be enabled  
simultaneously with a single write to the control register. For a write to use the write buffer, both  
the W bit in the control register and the B bit in the corresponding page table must be set. It is not  
possible to abort buffered writes externally. Stores will not merge with other data at the same line  
address in the write buffer with the exception of store multiples, which do merge.  
6.3.1  
6.3.2  
Bufferable Bit  
This bit controls whether a write operation may use the write buffer. Typically, main memory is  
bufferable and I/O space unbufferable.  
Write Buffer Operation  
When the CPU performs a store, the Dcaches are first checked. If one of the Dcaches hits on the  
store and the protection for the location and mode of the store allows the write, then the write  
completes in the Dcaches and the write buffer is not used. If the location misses in the Dcaches,  
then the translation entry for that address is inspected and the state of the B and C bits determines  
which of the three following actions are performed. If the write buffer is disabled via the SA-1100  
control register, writes are treated as if the B bit is a zero.  
6.3.2.1  
Writes to a Bufferable and Cacheable Location (B=1,C=1)  
If the write buffer is enabled and the processor performs a write to a bufferable and cacheable  
location, and the data is in one of the caches, then the data is written to that cache, and the cache  
line is marked dirty. If a write to a bufferable area misses in both data caches, the data is placed in  
the write buffer and the CPU continues execution. The write buffer performs the external write  
sometime later. If a write is performed and the write buffer is full, then the processor is stalled until  
there is sufficient space in the buffer. No write buffer merging is allowed in the SA-1100 except  
during store multiples.  
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Caches, Write Buffer, and Read Buffer  
6.3.2.2  
6.3.2.3  
Writes to a Bufferable and Noncacheable Location (B=1,C=0)  
If the write buffer is enabled and the processor performs a write to a bufferable but noncacheable  
location and misses in the Dcaches, the data is placed in the write buffer and the CPU continues  
execution. As with the cacheable case, merging is allowed only on store multiples. The write buffer  
performs the external write sometime later.  
Unbufferable Writes (B=0)  
If the write buffer is disabled or the CPU performs a write to an unbufferable area, the processor is  
stalled until the write buffer empties and the write completes externally. This requires several  
external clock cycles.  
6.3.3  
Enabling the Write Buffer  
To enable the write buffer, ensure that the MMU is enabled by setting bit 0 in the control register,  
then enable the write buffer by setting bit 3 in the control register. The MMU and write buffer can  
be enabled simultaneously with a single write to the control register.  
6.3.3.1  
Disabling the Write Buffer  
To disable the write buffer, clear bit 3 in the control register. Any writes already in the write buffer  
will complete normally, but a drain write buffer needs to be done to force all writes out to memory.  
Note: The write buffer is used for copy-backs from the Dcaches even when they are disabled.  
6.4  
Read Buffer (RB)  
The SA-1100 contains a software-programmable read buffer that can increase the performance of  
critical loop code by prefetching data. The RB enables the preallocation of read-only data into one  
of four 32-byte buffers without stalling the pipe. For subsequent loads that hit in the RB, data is  
sourced from the buffer instead of the Dcaches at a rate of 1 word per core clock. Also, because  
the programmer specifies which entry of the RB is used, critical data can be “locked” in to  
eliminate bus latency.  
The RB is controlled using coprocessor 15, register 9, and provides the capability to allocate 1  
word, a half-line (4 words), or a full line (8 words) into one of four entries of the RB. (See  
Chapter 5, “Coprocessors” for a detailed RB coprocessor description.) Half-line loads are  
automatically aligned onto half-block boundaries (the lower four address bits are ignored).  
Full-line loads are automatically aligned onto line boundaries (the lower five address bits are  
ignored). For partial cache line RB loads, only the words actually fetched are marked valid and can  
be sourced from the buffer. A small queue is used to ensure that subsequent RB load instructions go  
out in order.  
When an RB allocate instruction is executed, the virtual address is looked up in the TB to check for  
a translation hit and possible access violations. If the access misses in the TB, the pipe is stalled  
until the page is fetched through the normal hardware tablewalk mechanism. If an access violation  
occurs, the RB load is NOP’d. For example, an RB allocate instruction can generate a data abort.  
Once the RB allocate has received a TB hit and no access violations, a bus access is requested that  
fills the appropriate buffer without stalling the core pipeline. Subsequent load instructions to this  
virtual address result in an RB hit and data is sourced from the appropriate entry to the core.  
6-6  
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Caches, Write Buffer, and Read Buffer  
Any two data words with the same virtual address may not be contained in the RB at the same time.  
If an RB allocate references a data word that is already contained in another RB entry, then the old  
RB entry is invalidated and the new allocation is performed. It is possible for a portion of a cache  
clock at a given virtual address to be contained in one RB entry while another portion of the same  
block is contained in another RB entry. However, a given word can not be in more than one entry at  
a time.  
If a load instruction misses in the RB, then a normal cache fill is performed (provided the cache is  
enabled and the page is marked cacheable). It then presents the possibility of having a partial line  
resident in the RB as well as having the line present in one of the Dcaches. This presents coherency  
issues that must be managed by software. If this situation does occur and the addressed data is in  
both the Dcache and the RB, then the data is sourced from the RB. If an RB entry contains a partial  
cache block (1 or 4 words), then those words will be sourced from the RB while the remaining  
words are sourced from the data cache or memory.  
RB allocate instructions are not affected by the cache enable bit (bit 2 in the control register) or by  
the C bit in the MMU. Any RB allocate to a valid RB entry causes that RB entry to be invalidated,  
followed by a new allocation for the desired data. This occurs regardless of the address of the data  
currently in the buffer. For example, back-to-back RB allocate instructions to the same entry at the  
same address will invalidate the entry caused by the first instruction prior to performing the second  
fill.  
An RB allocate or a load instruction that is issued to an RB entry currently being filled will stall  
until the fill completes. If a data abort is signaled on a read buffer allocate, the fill completes. After  
that, if a load to that entry is attempted, a data abort exception is issued. The coprocessor 15  
register provides the ability to invalidate individual entries in the RB or to invalidate the entire  
buffer in one operation. RB coherency must be managed in software. Writes to addresses present in  
the read buffer are not written into the buffer. Specific RB entries must be invalidated before  
writing to the addresses or changing the page tables of the entries. Coherency is not checked  
between the RB and the WB. The WB should be drained prior to performing an RB load.  
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Memory-Management Unit (MMU) 7  
This chapter describes the memory-management functions.  
7.1  
Overview  
The Intel® StrongARM® SA-1100 Microprocessor (SA-1100) implements the standard ARM™  
memory-management functions using two 32-entry fully associative translation buffers (TBs). One  
is used for instruction accesses and the other for data accesses. On a TB miss, the translation table  
hardware is invoked to retrieve the translation and access permission information. Once retrieved,  
if the entry maps to a valid page or section, then the information is placed into the TB. The  
replacement algorithm in the TB is round robin. For an invalid page or section, an abort is  
generated and the entry is not placed in the TB.  
7.1.1  
MMU Registers  
See Section 5.2, “Coprocessor 15 Definition” on page 5-2 for a description of the Memory  
Management Unit (MMU) coprocessor 15 registers supported by the SA-1100.  
7.2  
MMU Faults and CPU Aborts  
The MMU generates four faults:  
Alignment fault  
Translation fault  
Domain fault  
Permission fault  
Alignment faults are generated by word loads or stores with the low-order two address bits  
nonzero, and by load or store half words when the low-order address bit is a one. Translation faults  
are generated by access to pages marked invalid by the memory-management page tables. Domain  
faults and permission faults are generated by accesses to memory that are protected by the current  
mode, domain, and page protection. See the ARM Architecture Reference for more information. In  
addition, an external abort may be raised on external data accesses.  
7.3  
Data Aborts  
The SA-1100 takes a data abort exception due to: MMU-generated exceptions, accessing reserved  
memory space, and assertion of the abort pin while accessing expansion memory. Writes to  
memory areas marked as bufferable ignore the external abort pin.  
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Memory-Management Unit (MMU)  
7.3.1  
Cacheable Reads (Linefetches)  
A linefetch can be safely aborted on any word in the transfer. If an abort occurs during the  
linefetch, the cache is purged so it will not contain invalid data. If the abort happens before the  
word that was requested by the access is returned, the load is aborted. If the abort happens after the  
word that was requested by the access is returned, the load completes and the fill is aborted (but no  
exception is generated).  
7.3.2  
Buffered Writes  
Buffered writes cannot be externally aborted. Therefore, the system should be configured such that it  
does not perform buffered writes to areas of memory that are capable of flagging an external abort.  
7.4  
Interaction of the MMU, Icache, Dcache, and Write  
Buffer  
The MMU, Icache, Dcache, and WB can be enabled or disabled independently. The Icache can be  
enabled with the MMU enabled or disabled. However, the Dcache and WB can only be enabled  
when the MMU is enabled. Because the write buffer is used to hold dirty copy-back cached lines  
from the Dcache, it must be enabled along with the Dcache. Therefore, only four of the eight  
combinations of the MMU, Dcache, and WB enables are valid. There are no hardware interlocks  
on these restrictions, so invalid combinations will cause undefined results.  
Table 7-1.  
Valid MMU, Dcache, and Write Buffer Combinations  
MMU  
Dcache  
Write Buffer  
Off  
On  
On  
On  
Off  
Off  
Off  
On  
Off  
Off  
On  
On  
The following procedures must be observed.  
To enable the MMU:  
1. Program the translation table base and domain access control registers.  
2. Program level 1 and level 2 page tables as required.  
3. Enable the MMU by setting bit 0 in the control register.  
7-2  
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Memory-Management Unit (MMU)  
Note: Care must be taken if the translated address differs from the untranslated address because the three  
instructions following the enabling of the MMU will have been fetched using “flat translation”,  
and enabling the MMU may be considered a branch with delayed execution. A similar situation  
occurs when the MMU is disabled. Consider the following code sequence:  
MOV  
MCR  
R1, #0x1  
15,0,R1,0,0  
; Enable MMU  
Fetch nontranslated  
Fetch nontranslated  
Fetch nontranslated  
Fetch Translated  
To disable the MMU:  
1. Disable the WB by clearing bit 3 in the control register.  
2. Disable the Dcache by clearing bit 2 in the control register.  
3. Disable the Icache by clearing bit 12 in the control register.  
4. Disable the MMU by clearing bit 0 in the control register.  
Note: If the MMU is disabled and subsequently reenabled, the contents of the TB is preserved. If the  
contents are now invalid, the TB should be flushed before reenabling the MMU.  
7.5  
Mini Data Cache  
The mini data cache is a 16-entry, 2-way set-associative data cache. It is accessed in parallel with  
the main data cache. A data reference is allocated into the mini data cache if the B and C bits in  
the MMU are 0 and 1, respectively. A line of data can reside only in one of the two Dcaches at any  
one time. Both Dcaches must be flushed prior to any page table manipulation that could change the  
allocation policy.  
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Clocks  
8
This section describes the Intel® StrongARM® SA-1100 Microprocessor (SA-1100) clocks. The  
following diagram shows the distribution of clocks in the SA-1100. The 3.6864-MHz oscillator  
feeds both PLLs. The primary PLL provides clocks for the core logic and a 7.36-MHz clock for  
several of the serial controllers. The core, Dcaches, and read and write buffers use either the  
full-speed core clock or the divided-down clock. The LCD controller, DMA, memory controller,  
and GPIO use the core clock divided by 2 (RCLK). The 32.768-kHz oscillator feeds the real-time  
clock (RTC) and the power manager logic. The secondary PLL provides the clock for the UDC, the  
ICP, and the MCP. The oscillators and PLLs are completely integrated with the SA-1100 and  
require no external devices other than the crystals for operation.  
ARM™  
SA-1 Core  
32.768-kHz  
Oscillator  
3.6864-MHz  
Oscillator  
Divide  
by 2  
Icache  
Primary PLL  
59 MHz – 200 MHz  
RTC  
and  
Dcache  
Power  
Manager  
7.36 MHz  
Write  
Buffer  
Secondary PLL  
48 MHz  
Read  
Buffer  
Peripherals  
SDLC UART – 7.36 MHz  
ICP – 7.36 or 48 MHz  
MCP/SSP – 7.36 or 12 MHz  
PPC – 7.36 MHz  
GPIO<27>  
LCD  
DMA  
Memory  
I/O  
Controller Controller Controller  
Control  
UDC – 48 MHz  
8.1  
SA-1100 Crystal Oscillators  
The SA-1100 clocks are derived from two crystals connected to onchip oscillators. The first clock  
source is a 3.6864-MHz crystal that feeds the CPU PLL and the 48-MHz PLL. The CPU PLL  
multiplies the oscillator output up to the core frequency. This frequency is then divided down to  
generate baud rates for the serial ports. If the UARTs are not being used or do not need standard  
baud rates, then the 3.6864 -Hz oscillator may be replaced with a 3.5795-MHz crystal to generate  
frequencies as shown in Table 8-1.  
The second oscillator is connected to a 32.768-kHz crystal. The output of this oscillator clocks the  
power management controller and the real-time clock (RTC).  
Oscillator Specifications” for detailed specifications of the crystal oscillators.  
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Clocks  
8.2  
Core Clock Configuration Register  
The core clock frequency is configured by software through the core clock configuration field  
(CCF<4:0>) in the power manager phase-locked loop (PLL) configuration register (PPCR). This  
field should be programmed during the boot sequence for the desired full-speed operation.  
nRESET clears the field by selecting the lowest frequency operation.  
See Section 9.5, “Power Manager” on page 9-26 for the physical address used to access this  
register.  
Table 8-1 shows the core clock frequency as a function of the CCF setting.  
Table 8-1.  
Core Clock Configurations  
CCF<4:0>  
Core Clock Frequency in MHz  
3.6864-MHz Crystal Oscillator 3.5795-MHz Crystal Oscillator  
00000  
59.0  
57.3  
00001  
00010  
00011  
73.7  
71.6  
88.5  
85.9  
103.2  
118.0  
132.7  
147.5  
162.2  
176.9  
191.7  
206.4  
221.2  
Not supported.  
100.2  
114.5  
128.9  
143.2  
157.5  
171.8  
186.1  
200.5  
214.8  
00100  
00101  
00110  
00111  
01000  
01001  
01010  
01011  
01100– 11111  
8.2.1  
Restrictions on Changing the Core Clock Configuration  
When the CPU writes to the PPCR, the core clock PLL and the 48-MHz PLL are stopped for a  
period of time to allow the core clock PLL to relock to the new frequency. When these PLLs are  
stopped, the core clock and all clocks derived from that clock are stopped. When this happens,  
certain units within the SA-1100 (the LCD controller, all serial controllers, the DMA controller,  
and the OS timer) will experience an interruption in operation for approximately 150 microseconds  
after the PPCR is written.  
Because of these restrictions, it is recommended that the user not change the PPCR except  
immediately following a hard reset or immediately following wake-up from sleep mode. The LCD  
controller, all serial controllers (except the UDC), the DMA controller, and the OS timer are  
already disabled and are not affected by an interruption in their clock stream. In addition to these  
restrictions, the PPCR must be written prior to enabling clock switching. Note that the 32.768-kHz  
clock is not affected by any change in the PPCR and units using this clock (power management,  
RTC) do not see any interruption in service during the 150 microsecond period.  
8-2  
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Clocks  
8.3  
Driving SA-1100 Crystal Pins from an External  
Source  
In most applications, a 3.6864-MHz crystal will be connected between the PXTAL and the  
PEXTAL pins. Similarly, a 32.768-kHz crystal will be connected between the TXTAL and  
TEXTAL pins. In some applications, supplying these clocks from an external source may be  
preferred. This is accommodated in the SA-1100 design by:  
Supplying the 32.768-kHz clock from an external source  
— Only the TXTAL pin is driven. The TEXTAL pin must be left floating.  
— The peak-to-peak voltage swing on TXTAL must be at least 0.6 V and the voltage on the  
pin must remain within the range of 0 V to 1 V, independent of the other power supply  
voltages applied to the processor.  
Supplying a 3.6864-MHz clock from an external source  
— Both PXTAL and PEXTAL are driven with complementary signals.  
— The peak-to-peak voltage swing on PXTAL and PEXTAL must be at least 0.6 V and the  
voltage on the pin must remain in the range of 0 V to 1 V, independent of the other power  
supply voltages applied to the processor.†  
— When an external clock is being used, the pull-down path in the internal 3.6864 MHz  
oscillator is active. In order to limit the current into the internal oscillator, it is  
recommended that the minimum impedance to the positive supply be controlled. The  
maximum current sourced by the external clock source when the clock is at its maximum  
positive voltage should be about 1 mA.†  
— The maximum impedance of the external clock source is set by the minimum slew rate at  
the PXTAL and PEXTAL pins, approximately 1 V per 100 ns.†  
†These constraints can be satisfied by the following suggestions:  
For applications in which a pulse generator is available, drive differential 1-V signals through  
series 1-K resistors (after the usual 50-ohm terminators-to-ground).  
To supply external clock signals from a 3.3-V supply, drive signals with open collector or  
tristatable drivers. Set high level with 3.3 K from 3.3 V to the output and 1.3 K from the output  
to ground.  
To supply external clock signals from a 1.5-V supply, drive signals with open collector or  
tristatable drivers. Set high level with 1.5 K from 1.5 V to the output and 2.7 K from output to  
ground. This solution may be preferred in portable applications that turn off the 1.5-V supply  
in sleep mode because this would eliminate the current through the resistors in sleep mode.  
The two pairs of crystal pins are located close to each other on the processor. This arrangement is  
advantageous when there are crystals connected to the pins because the low signal swings and slow  
edges result in limited noise coupling between the pins. If one of the crystals is replaced by an  
independent signal source and the other is not, some degradation of the remaining crystal oscillator  
performance can result due to increased noise coupling. If only one crystal is being used, this effect  
can be reduced by limiting the speed of the edge rate on the pin driven by the independent source.  
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Clocks  
If the PXTAL or TXTAL pin is driven above the voltage indicated, there will be no permanent  
damage to the processor for pin voltages less than 2.5 V. However, ESD diodes on these pins will  
attempt to clamp the voltage at approximately 1.5 V. The clamping action results in significant  
noise injected into an internally generated supply used by several sensitive circuits on the  
processor. Consequently, driving this pin higher than the 1 V limit can result in unpredictable  
operation not obviously connected with the crystal pins. Users should refrain from driving the  
crystal pins higher than 1 V even if there is no obvious side effect.  
Note: In every system, there must be a provision for both a 3.6864-MHz and a 32.768-kHz source either  
from an external oscillator or a crystal.  
8.4  
Clocking During Test  
If TCK_BYP is high, then the PLLs and oscillators are not used and the high-speed core clock is  
supplied externally on the TESTCLK pin. This mode is for testing only and is not supported for  
standard operation.  
8-4  
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System Control Module  
9
This chapter describes the system control module that controls several processor-wide system  
functions. The units contained in the system control module are: the general-purpose I/O ports, the  
interrupt controller, the real-time clock, the operating system timer, the power manager, and the  
reset controller.  
9.1  
General-Purpose I/O  
The Intel® StrongARM® SA-1100 Microprocessor (SA-1100) provides 28 general-purpose I/O  
(GPIO) port pins for use in generating and capturing application-specific input and output signals.  
Each pin is programmable as an input or output and as an interrupt source. All 28 pins are  
configured as inputs during the assertion of reset, and remain inputs until they are configured  
otherwise.  
Each GPIO pin can be configured as an input or an output by programming the GPIO pin direction  
register (GPDR). When programmed as an output, the pin can be controlled by writing to the GPIO  
pin output set register (GPSR) and the GPIO pin output clear register (GPCR). Writing to these  
registers controls the output data register, which is not directly readable or writable. The set and  
clear registers can be written regardless of whether the pin is configured as an input or an output.  
The programmed output state will take effect when the pin is reconfigured as an output.  
When programmed as an input, the current state of each GPIO pin can be read through the GPIO  
pin-level register (GPLR). This register can be read at any time and can be used to confirm the state  
of the pin when it is configured as an output. In addition, each GPIO pin can be programmed to  
detect a rising and/or falling edge through the GPIO rising-edge detect register (GRER) and GPIO  
falling-edge detect register (GFER). The state of the edge detect can be read through the GPIO  
edge detect status register (GEDR). These edge detects can be programmed to generate an interrupt  
(see the Section 9.2, “Interrupt Controller” on page 9-11) or to serve as a wake-up event to bring  
the SA-1100 out of sleep mode (see the Section 9.5, “Power Manager” on page 9-26).  
When the SA-1100 enters sleep mode, the contents of the power manager sleep state register  
(PGSR) is loaded into the output data register. If the particular pin is programmed as an output,  
then the state in the PGSR will be driven onto the pin before entering sleep. When the SA-1100  
exits sleep mode, these values remain until reprogrammed by writing to the GPSR and GPCR.  
Some GPIO pins can also serve an alternate function within the SA-1100. Certain modes within the  
serial controllers and LCD controller require extra pins. These functions are hardwired into specific  
GPIO pins and their use is described in the following sections. Even though a GPIO pin has been  
taken over for an alternate function, the user must still program the proper direction of that pin  
through the GPDR. Details on alternate functions are provided in following sections. Figure 9-1  
shows a block diagram of a single GPIO pin.  
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System Control Module  
Figure 9-1. General-Purpose I/O Block Diagram  
Pin Direction  
Register  
Alternate Function  
Register  
Pin Set and  
Clear Registers  
0
1
GPIO Pin  
Alternate Function  
(Output)  
Alternate Function  
(Input)  
Edge Detect  
Status Register  
Edge  
Detect  
Rising Edge Detect  
Enable Register  
Falling Edge Detect  
Enable Register  
Pin-Level  
Register  
9.1.1  
GPIO Register Definitions  
There are a total of eight registers within the GPIO control block: one is used to monitor pin state;  
two are used to control pin state; one is used to control pin direction; two are used to specify a pin’s  
edge type that should be detected; and one is used to flag when specified edge types are detected on  
pins. The last register indicates whether a pin is used as normal GPIO or whether it is taken over by  
the alternate function. Note that the pin direction register (GPDR) is the only register that is  
initialized by reset. The values in all other GPIO registers are unknown following reset and must be  
initialized by software.  
9-2  
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System Control Module  
9.1.1.1  
GPIO Pin-Level Register (GPLR)  
The state of each of the GPIO port pins is visible through the GPIO pin-level register (GPLR).  
Each bit number corresponds to the port pin number from bit 0 to bit 27. This is a read-only register  
that is used to determine the current level of a particular pin (regardless of the programmed pin  
direction).  
The following table shows the locations of the 28 pin-level bits within the GPLR. This is a  
read-only register. For reserved bits, reads return zero; a question mark indicates that the values are  
unknown at reset.  
Bit  
Read  
Reset  
-
31  
30  
29  
0
28  
0
27  
PL27  
?
26  
PL26  
?
25  
PL25  
?
24  
PL24  
?
23  
PL23  
?
22  
PL22  
?
21  
PL21  
?
20  
PL20  
?
19  
PL19  
?
18  
PL18  
?
17  
PL17  
?
16  
PL16  
?
Reserved  
0
-
0
Bit  
15  
14  
13  
PL13  
?
12  
PL12  
?
11  
PL11  
?
10  
PL10  
?
9
PL9  
?
8
PL8  
?
7
PL7  
?
6
PL6  
?
5
PL5  
?
4
PL4  
?
3
PL3  
?
2
PL2  
?
1
PL1  
?
0
PL0  
?
Read PL15 PL14  
Reset  
?
?
Bit  
Name  
Description  
{n}  
PL{n}  
GPIO port pin level n (where n = 0 through 27).  
0 – Pin state is low.  
1 – Pin state is high.  
31.. 28  
Reserved.  
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System Control Module  
9.1.1.2  
GPIO Pin Direction Register (GPDR)  
Pin direction is controlled by programming the GPIO pin direction register (GPDR). The GPDR  
contains one direction control bit for each of the 28 port pins. If a direction bit is programmed to a  
one, the port is an output. If it is programmed to a zero, it is an input. At hardware reset, all bits in  
this register are cleared, configuring all GPIO pins as inputs. Soft resets and sleep reset have no  
effect on this register. For reserved bits, writes are ignored and reads return zero. The following  
table shows the location of each pin direction bit in the GPIO pin direction register.  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Bit  
R/W  
Reserved  
PD27 PD26 PD25 PD24 PD23 PD22 PD21 PD20 PD19 PD18 PD17 PD16  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Reset  
15  
14  
13  
12  
11  
10  
9
PD9  
0
8
PD8  
0
7
PD7  
0
6
PD6  
0
5
PD5  
0
4
PD4  
0
3
PD3  
0
2
PD2  
0
1
PD1  
0
0
PD0  
0
Bit  
R/W  
PD15 PD14 PD13 PD12 PD11 PD10  
0
0
0
0
0
0
Reset  
Bit  
Name  
Description  
{n}  
PD{n}  
GPIO port pin direction n (where n = 0 through 27).  
0 – Pin configured as an input.  
1 – Pin configured as an output.  
31..28  
Reserved.  
9-4  
SA-1100 Developer’s Manual  
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System Control Module  
9.1.1.3  
GPIO Pin Output Set Register (GPSR) and Pin Output Clear Register  
(GPCR)  
When a port is configured as an output, the user controls the state of the pin by writing to either the  
GPIO pin output set register (GPSR) or the GPIO pin output clear register (GPCR). An output pin  
is set by writing a one to its corresponding bit within the GPSR. To clear an output pin, a one is  
written to the corresponding bit within the GPCR. These are write-only registers. Reads return  
unpredictable values. Writing a zero to any of the GPSR or GPCR bits has no effect. Writing a one  
to a GPSR or GPCR bit corresponding to a pin that is configured as an input has no effect. For  
reserved bits, writes are ignored. The following tables show the locations of the GPSR bits and the  
locations of the GPCR bits. These are write-only registers and reset values do not apply.  
Bit  
Write  
Reset  
-
31  
-
30  
29  
-
28  
-
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
PS27 PS26 PS25 PS24 PS23 PS22 PS21 PS20 PS19 PS18 PS17 PS16  
-
-
-
-
-
-
-
-
-
-
-
-
-
Bit  
15  
14  
13  
12  
11  
10  
9
PS9  
-
8
PS8  
-
7
PS7  
-
6
PS6  
-
5
PS5  
-
4
PS4  
-
3
PS3  
-
2
PS2  
-
1
PS1  
-
0
PS0  
-
Write PS15 PS14 PS13 PS12 PS11 PS10  
Reset  
-
-
-
-
-
-
Bit  
Name  
Description  
{n}  
PS{n}  
GPIO output pin set n (where n = 0 through 27).  
0 – Pin level unaffected.  
1 – If pin configured as an output, set pin level high (one).  
Reserved.  
31..28  
Bit  
Write  
Reset  
31  
30  
29  
-
28  
-
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
PC27 PC26 PC25 PC24 PC23 PC22 PC21 PC20 PC19 PC18 PC17 PC16  
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Bit  
15  
14  
13  
12  
11  
10  
9
PC9  
-
8
PC8  
-
7
PC7  
-
6
PC6  
-
5
PC5  
-
4
PC4  
-
3
PC3  
-
2
PC2  
-
1
PC1  
-
0
PC0  
-
Write PC15 PC14 PC13 PC12 PC11 PC10  
Reset  
-
-
-
-
-
-
Bit  
Name  
Description  
{n}  
PC{n}  
GPIO output pin clear n (where n = 0 through 27).  
0 – Pin level unaffected.  
1 – If pin configured as an output, clear pin level low (zero).  
Reserved.  
31.. 28  
The user can test a bit within the GPLR corresponding to a pin that is configured as an output after  
having set or cleared the pin state to determine if there is an external conflict on the pin. For  
example, if an off-chip device is driving a GPIO output pin high and the user has cleared the pin’s  
state by writing a one to its GPCR bit, the user can read the GPLR, then compare the written value  
(zero) to the actual value (one) to detect the conflict.  
SA-1100 Developer’s Manual  
9-5  
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System Control Module  
9.1.1.4  
GPIO Rising-Edge Detect Register (GRER) and Falling-Edge Detect  
Register (GFER)  
Each GPIO port can also be programmed to detect a rising-edge, falling-edge, or either transition  
on a pin. When an edge is detected that matches the type of edge programmed for the pin, a status  
bit is set. The interrupt controller can be programmed to signal an interrupt to the CPU or wake up  
the SA-1100 from sleep mode when any one of these status bits is set.  
The GPIO rising-edge and falling-edge detect registers (GRER and GFER, respectively) are used  
to select the type of transition on a GPIO pin that causes a bit within the GPIO edge detect status  
register (GEDR) to be set. For a given GPIO port pin, its corresponding GRER bit is set to cause a  
GEDR status bit to be set when the pin transitions from logic level zero (0) to one (1). Likewise,  
GFER is used to set the corresponding GEDR status bit when a transition from logic level one (1)  
to zero (0) occurs. When the corresponding bits are set in both registers, either a falling- or a  
rising-edge transition causes the corresponding GEDR status bit to be set.  
The following table shows both the rising-edge and falling-edge enable bit locations corresponding  
to all 28 port pins. For reserved bits, writes are ignored and reads return zero; a question mark  
indicates that the values are unknown at reset.  
GRER  
Bit  
R/W  
31  
0
30  
29  
0
28  
0
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
RE27 RE26 RE25 RE24 RE23 RE22 RE21 RE20 RE19 RE18 RE17 RE16  
Reset  
0
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
15  
14  
13  
12  
11  
10  
9
RE9  
?
8
RE8  
?
7
RE7  
?
6
RE6  
?
5
RE5  
?
4
RE4  
?
3
RE3  
?
2
RE2  
?
1
RE1  
1
0
RE0  
1
R/W RE15 RE14 RE13 RE12 RE11 RE10  
Reset  
?
?
?
?
?
?
Bit  
Name  
Description: GPIO Rising-Edge Detect Register (GRER)  
{n}  
RE{n}  
GPIO pin n rising-edge detect (where n = 0 through 27).  
0 – Disable rising-edge detect.  
1 – Set corresponding GEDR status bit when a rising edge is detected on the GPIO pin.  
31.. 28  
Reserved.  
GFER  
Reset  
Bit  
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
R/W  
Reserved  
FE27 FE26 FE25 FE24 FE23 FE22 FE21 FE20 FE19 FE18 FE17 FE16  
Reset  
0
0
0
0
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
15  
14  
13  
12  
11  
10  
9
FE9  
?
8
FE8  
?
7
FE7  
?
6
FE6  
?
5
FE5  
?
4
FE4  
?
3
FE3  
?
2
FE2  
?
1
FE1  
1
0
FE0  
1
R/W FE15 FE14 FE13 FE12 FE11 FE10  
Reset  
?
?
?
?
?
?
Bit  
Name  
Description: GPIO Falling-Edge Detect Register (GRER)  
{n}  
FE{n}  
GPIO pin n falling-edge detect (where n = 0 through 27).  
0 – Disable falling-edge detect.  
1 – Set corresponding GEDR status bit when a falling edge is detected on the GPIO pin.  
31..28  
Reserved.  
9-6  
SA-1100 Developer’s Manual  
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System Control Module  
9.1.1.5  
GPIO Edge Detect Status Register (GEDR)  
The GPIO edge detect status register (GEDR) contains 28 status bits that correspond to the 28  
GPIO port pins. When an edge detect occurs on a pin that matches the type of edge programmed in  
the GRER and/or GFER registers, the corresponding status bit is set in GEDR. Once a GEDR bit is  
set, the CPU must clear it. GEDR status bits are cleared by writing a one to them. Writing a zero to  
a GEDR status bit has no effect.  
Each edge detect that sets the corresponding GEDR status bit for GPIO pins 0 – 27 can trigger an  
interrupt request. Pins 27 – 11 together form a group that can cause one interrupt request to be  
triggered when any one of the GEDR status bits 27 – 11 is set. Each of GPIO pins 10 – 0 causes an  
independent first-level interrupt. See the Section 9.2, “Interrupt Controller” on page 9-11 for a  
description of the programming of GPIO interrupts. The following table shows a summary of  
GEDR; a question mark indicates that the values are unknown at reset.  
Bit  
R/W  
31  
0
30  
29  
0
28  
0
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
ED27 ED26 ED25 ED24 ED23 ED22 ED21 ED20 ED19 ED18 ED17 ED16  
Reset  
0
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
15  
14  
13  
12  
11  
10  
9
ED9  
?
8
ED8  
?
7
ED7  
?
6
ED6  
?
5
ED5  
?
4
ED4  
?
3
ED3  
?
2
ED2  
?
1
ED1  
?
0
ED0  
?
R/W ED15 ED14 ED13 ED12 ED11 ED10  
Reset  
?
?
?
?
?
?
Bit  
Name  
Description  
GPIO edge detect status n (where n = 0 through 27).  
{n}  
ED{n}  
0 – No edge detect has occurred on pin as specified in GRER and/or GFER.  
1 – Edge detect has occurred on pin as specified in GRER and/or GFER.  
31..28  
Reserved.  
SA-1100 Developer’s Manual  
9-7  
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System Control Module  
9.1.1.6  
GPIO Alternate Function Register (GAFR)  
The GPIO alternate function register (GAFR) contains 28 control bits that correspond to the 28  
GPIO port pins. When the processor sets a bit in the GAFR, the corresponding GPIO pin is  
switched over to that pin’s alternate function. See the following section for details on alternate  
functions. This register is cleared to all zeros on all reset conditions.  
Bit  
R/W  
31  
0
30  
29  
0
28  
0
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
AF27 AF26 AF25 AF24 AF23 AF22 AF21 AF20 AF19 AF18 AF17 AF16  
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit  
15  
14  
13  
12  
11  
10  
9
AF9  
0
8
AF8  
0
7
AF7  
0
6
AF6  
0
5
AF5  
0
4
AF4  
0
3
AF3  
0
2
AF2  
0
1
AF1  
0
0
AF0  
0
R/W AF15 AF14 AF13 AF12 AF11 AF10  
Reset  
0
0
0
0
0
0
Bit  
Name  
Description  
GPIO alternate function bits (where n = 0 through 27).  
{n}  
AF{n}  
A bit set in this register indicates that the corresponding GPIO pin is to be used for its  
alternate function. A zero in this register indicates that the corresponding GPIO pin is to  
be used for its normal GPIO function.  
31..28  
Reserved.  
9-8  
SA-1100 Developer’s Manual  
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System Control Module  
9.1.2  
GPIO Alternate Functions  
Most GPIO pins have an alternate function that can be invoked to enable additional functionality  
within the SA-1100. If a GPIO is used for this alternate function, then it cannot be used as a GPIO  
at the same time. Pins 0 and 1 are reserved because of their special use during sleep mode and are  
not available for any alternate function. The following table shows each GPIO pin and its  
corresponding alternate function. For more details on an alternate function, see the section that  
corresponds to its name in the Unit column in the table.  
Pin  
Alternate Function  
Direction  
Output  
Unit  
Signal Description  
GP<27>  
GP<26>  
GP<25>  
GP<24>  
GP<23>  
GP<22>  
32KHZ_OUT  
RCLK_OUT  
RTC clock  
Clocks  
Clocks  
RTC  
Raw 32.768-kHz oscillator output  
Internal clock/2  
Output  
Output  
Trimmed 1-Hz clock  
Reserved  
TREQB  
Input  
Input  
Test controller  
Test controller  
TIC request B  
TREQA/MBREQ  
Either TIC request A or MBREQ  
Either TIC acknowledge or  
MBGNT  
GP<21>  
TIC_ACK/MBGNT  
Output  
Test controller  
Serial port 4  
GP<21>  
GP<20>  
GP<19>  
GP<18>  
GP<17>  
GP<16>  
GP<15>  
GP<14>  
GP<13>  
GP<12>  
GP<11>  
GP<10>  
MCP_CLK  
Input  
MCP clock in  
UART_SCLK3  
SSP_CLK  
Input  
Serial port 3:UART Sample clock input  
Serial port 2:SSP Sample clock input  
Input  
UART_SCLK1  
SDLC_AAF  
SDLC_SCLK  
UART_RXD  
UART_TXD  
SSP_SFRM  
SSP_SCLK  
SSP_RXD  
Input  
Serial port 1:UART Sample clock input  
Serial port 1:SDLC Abort after frame control  
Serial port 1:SDLC Geoport clock out  
Serial port 1:UART UART receive  
Output  
I/O  
Input  
Output  
Output  
Output  
Input  
Serial port 1:UART UART transmit  
Serial Port 4:SSP  
Serial port 4:SSP  
Serial port 4:SSP  
Serial port 4:SSP  
SSP frame clock  
SSP serial clock  
SSP receive  
SSP_TXD  
Output  
SSP transmit  
High-order data pins for  
split-screen color LCD support  
GP<2..9> LDD<8..15>  
Output  
LCD controller  
GP<1>  
GP<0>  
Reserved  
Reserved  
No alternate function  
No alternate function  
—-  
SA-1100 Developer’s Manual  
9-9  
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System Control Module  
9.1.3  
GPIO Register Locations  
The following table shows the registers associated with the GPIO block and the physical addresses  
used to access them.  
Address  
0h 9004 0000  
Name  
GPLR  
Description  
GPIO pin-level register  
0h 9004 0004  
0h 9004 0008  
0h 9004 000C  
0h 9004 0010  
0h 9004 0014  
0h 9004 0018  
0h 9004 001C  
GPDR  
GPSR  
GPCR  
GRER  
GFER  
GEDR  
GAFR  
GPIO pin direction register  
GPIO pin output set register  
GPIO pin output clear register  
GPIO rising-edge detect register  
GPIO falling-edge detect register  
GPIO edge detect status register  
GPIO alternate function register  
9-10  
SA-1100 Developer’s Manual  
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System Control Module  
9.2  
Interrupt Controller  
The SA-1100 interrupt controller provides masking capability for all interrupt sources and  
combines them into their final state, either an FIQ or IRQ processor interrupt. The interrupt  
hierarchy of the SA-1100 is a two-level structure.  
The first level of the structure, represented by the interrupt controller IRQ pending register (ICIP)  
and the interrupt controller FIQ pending register (ICFP) contain the all-enabled and unmasked  
interrupt sources. Interrupts are enabled at their source and unmasked in the interrupt controller  
mask register (ICMR). The ICIP contains the interrupts that are programmed to generate an IRQ  
interrupt. The ICFP contains all valid interrupts that are programmed to generate an FIQ interrupt.  
This routing is programmed via the interrupt controller level register (ICLR).  
The second level of the interrupt structure is represented by registers contained in the source device  
(the device generating the first-level interrupt bit). Second-level interrupt status gives additional  
information about the interrupt and is used inside the interrupt service routine. In general, multiple  
second-level interrupts are OR’ed to produce a first- level interrupt bit. The enabling of interrupts  
is performed inside the source device.  
In most cases, the root source of an interrupt can be determined through reading two register  
locations: the ICIP or ICFP (depending on which interrupt handler the software is in) to determine  
the interrupting device, followed by the status register within that device to find the exact function  
needing service. When the SA-1100 is in idle mode (see the Section 9.5, “Power Manager” on  
page 9-26), any enabled interrupt causes it to resume operation. The interrupt mask register is  
ignored during idle mode. Figure 9-2 shows a block diagram of the interrupt controller.  
Figure 9-2. Interrupt Controller Block Diagram  
All Other Qualified  
Interrupt Bits  
Interrupt Level  
Register  
31  
31  
Interrupt Mask  
Register  
FIQ  
Interrupt  
to  
Processor  
Interrupt Source  
Bit  
IRQ  
Interrupt  
to  
Interrupt Pending  
Register  
Processor  
IRQ Interrupt  
Pending Register  
FIQ Interrupt  
Pending Register  
9.2.1  
Interrupt Controller Register Definitions  
The interrupt controller contains four registers: the interrupt controller IRQ pending register  
(ICIP), the interrupt controller FIQ pending register (ICFP), the interrupt controller mask register  
(ICMR), and the interrupt controller level register (ICLR). Following reset, the FIQ and IRQ  
interrupts are disabled within the CPU, and the states of all of the interrupt controller’s registers are  
unknown and must be initialized by software before interrupts are enabled within the CPU.  
SA-1100 Developer’s Manual  
9-11  
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System Control Module  
9.2.1.1  
Interrupt Controller Pending Register (ICPR)  
The ICPR is a 32-bit read-only register that shows all active interrupts in the system. These bits are  
not affected by the state of the mask register (ICMR). The following table shows the pending  
interrupt source assigned to each bit position in the ICPR. Also included in the table are the source  
units for the interrupts and the number of second-level interrupts associated with each. For more  
detail on the second-level interrupts, see the section describing that unit.  
Bit Position  
Unit  
Source Module  
# of Level 2 Sources  
Bit Field Description  
IP<31>  
IP<30>  
IP<29>  
IP<28>  
IP<27>  
IP<26>  
IP<25>  
IP<24>  
IP<23>  
IP<22>  
IP<21>  
IP<20>  
IP<19>  
IP<18>  
IP<17>  
IP<16>  
IP<15>  
IP<14>  
IP<13>  
IP<12>  
IP<11>  
IP<10>  
IP<9>  
1
1
RTC equals alarm register.  
One Hz clock TIC occurred.  
OS timer equals match register 3.  
OS timer equals match register 2.  
OS timer equals match register 1.  
OS timer equals match register 0.  
Channel 5 service request.  
Channel 4 service request.  
Channel 3 service request.  
Channel 2 service request.  
Channel 1 service request.  
Channel 0 service request.  
SSP service request.  
Real-time clock  
1
System  
1
Operating system timer  
DMA controller  
1
1
3
3
3
3
3
3
Serial port 4b  
Serial port 4a  
Serial port 3  
3
Peripheral  
8
MCP service request.  
6
UART service request.  
Serial port 2  
6+6  
6
UART/HSSP service request.  
UART service request.  
Serial port 1b  
Serial port 1a  
Serial port 0  
5
SDLC service request.  
6
UDC service request.  
LCD controller  
General-purpose I/O  
12  
17  
1
LCD controller service request.  
“OR” of GPIO edge detects 27-11.  
GPIO<10> edge detect.  
System  
1
GPIO<9> edge detect.  
IP<8>  
1
GPIO<8> edge detect.  
IP<7>  
1
GPIO<7> edge detect.  
IP<6>  
1
GPIO<6> edge detect.  
IP<5>  
1
GPIO<5> edge detect.  
IP<4>  
1
GPIO<4> edge detect.  
IP<3>  
1
GPIO<3> edge detect.  
IP<2>  
1
GPIO<2> edge detect.  
IP<1>  
1
GPIO<1> edge detect.  
IP<0>  
1
GPIO<0> edge detect.  
Total level 2 interrupt  
sources  
110  
Several units have more than one source per interrupt signal. When an interrupt is signalled from  
one of these units, the interrupt handler routine identifies which interrupt was signalled using the  
interrupt controller’s flag register (this identifies the unit that made the request, but not the exact  
source). The handler then reads the interrupting unit’s status register to identify which source  
within the unit signalled the interrupt. For all interrupts that have one corresponding source, the  
interrupt handler routine needs to use only the interrupt controller’s registers to identify the exact  
cause of the interrupt.  
9-12  
SA-1100 Developer’s Manual  
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System Control Module  
9.2.1.2  
Interrupt Controller IRQ Pending Register (ICIP) and FIQ Pending  
Register (ICFP)  
The ICIP and the ICFP contain one flag per interrupt (32 total) that indicates an interrupt request  
has been made by a unit. Inside the interrupt service routine, the ICIP and ICFP are read to  
determine the interrupt source. In general, software then reads status registers within the  
interrupting device to determine how to service the interrupt.  
Bits within the ICPR are read only, and represent the logical OR of status bits for a given interrupt  
within the source unit. Once an interrupt has been serviced, the handler clears the pending interrupt  
at the source by writing a one to the necessary status bit. Clearing the interrupt status bit at the  
source automatically clears the corresponding ICIP and ICFP flag provided there are no other  
interrupt status bits set within the source unit.  
All interrupt source status bits are cleared by writing a one to them. Writing a zero to an interrupt  
status bit has no effect. The following table shows the bit locations corresponding to the 32  
separate interrupt pending status flags in the ICIP. The next table shows the bit locations  
corresponding to the 32 separate interrupt pending status flags in the ICFP. This is a read-only  
register.  
Bit  
Read  
Reset  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
IP31  
IP30  
IP29  
IP28  
IP27  
IP26  
IP25  
IP24  
IP23  
IP22  
IP21  
IP20  
IP19  
IP18  
IP17  
IP16  
These flags reflect the OR of the reset state of the individual interrupt status bits at the source unit.  
Bit  
Read  
Reset  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
4
3
2
1
0
IP15  
IP14  
IP13  
IP12  
IP11  
IP10  
IP9  
IP8  
IP7  
IP6  
IP5  
IP4  
IP3  
IP2  
IP1  
IP0  
These flags reflect the OR of the reset state of the individual interrupt status bits at the source unit.  
Bit  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Read FP31 FP30 FP29 FP28 FP27 FP26 FP25 FP24 FP23 FP22 FP21 FP20 FP19 FP18 FP17 FP16  
Reset  
These flags reflect the OR of the reset state of the individual interrupt status bits at the source unit.  
Bit  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
4
3
2
1
0
Read FP15 FP14 FP13 FP12 FP11 FP10  
Reset  
FP9  
FP8  
FP7  
FP6  
FP5  
FP4  
FP3  
FP2  
FP1  
FP0  
These flags reflect the OR of the reset state of the individual interrupt status bits at the source unit.  
SA-1100 Developer’s Manual  
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System Control Module  
9.2.1.3  
Interrupt Controller Mask Register (ICMR)  
The interrupt controller mask register (ICMR) contains one mask bit per pending interrupt bit (32  
total). The mask bits control whether a pending interrupt bit will generate a processor interrupt  
(IRQ or FIQ). When a pending interrupt becomes active, it is sent to the CPU only if its  
corresponding ICMR mask bit is set to a one. Note that the mask bits are ignored when the  
SA-1100 is in idle mode. While in idle, if any interrupt source makes a request, the corresponding  
pending bit is set and the interrupt automatically becomes active, regardless of the state of its mask  
bit.  
Mask bits serve two purposes. First, they allow periodic software polling of interruptible sources  
while preventing them from actually causing an interrupt. Second, they allow the interrupt handler  
routine to prevent interrupts of lower priority from occurring while still maintaining a list of  
pending interrupts that may have occurred previously (or during the servicing of another interrupt).  
The ICMR is not initialized at reset; a question mark indicates that the values are unknown at reset.  
The following table shows the bit locations corresponding to the 32 separate interrupt mask bits.  
Bit  
31  
30  
IM30  
?
29  
IM29  
?
28  
IM28  
?
27  
IM27  
?
26  
IM26  
?
25  
IM25  
?
24  
IM24  
?
23  
IM23  
?
22  
IM22  
?
21  
IM21  
?
20  
IM20  
?
19  
IM19  
?
18  
IM18  
?
17  
IM17  
?
16  
IM16  
?
R/W IM31  
Reset  
?
Bit  
15  
14  
IM14  
?
13  
IM13  
?
12  
IM12  
?
11  
IM11  
?
10  
IM10  
?
9
IM9  
?
8
IM8  
?
7
IM7  
?
6
IM6  
?
5
IM5  
?
4
IM4  
?
3
IM3  
?
2
IM2  
?
1
IM1  
?
0
IM0  
?
R/W IM15  
Reset  
?
Bit  
{n}  
Name  
IM{n}  
Description  
Interrupt mask n (where n = 0 through 31).  
0 – Pending interrupt is masked from becoming active (interrupts not sent to CPU, Power  
Manager).  
1 – Pending interrupt is allowed to become active (interrupt sent to CPU, Power  
Manager).  
Note: IM bits are ignored during idle mode.  
9-14  
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System Control Module  
9.2.1.4  
Interrupt Controller Level Register (ICLR)  
The interrupt controller level register (ICLR) controls whether a pending interrupt generates an  
FIQ or an IRQ CPU interrupt. If a pending interrupt is unmasked, the corresponding ICLR bit field  
is decoded to select which CPU interrupt should be asserted. If the interrupt is masked, then the  
corresponding bit in the ICLR has no effect. The following table shows the location of all interrupt  
level bits in the ICLR; question marks indicate that the values are unknown at reset.  
Bit  
R/W  
31  
IL31  
?
30  
IL30  
?
29  
IL29  
?
28  
IL28  
?
27  
IL27  
?
26  
IL26  
?
25  
IL25  
?
24  
IL24  
?
23  
IL23  
?
22  
IL22  
?
21  
IL21  
?
20  
IL20  
?
19  
IL19  
?
18  
IL18  
?
17  
IL17  
?
16  
IL16  
?
Reset  
Bit  
R/W  
15  
IL15  
?
14  
IL14  
?
13  
IL13  
?
12  
IL12  
?
11  
IL11  
?
10  
IL10  
?
9
IL9  
?
8
IL8  
?
7
IL7  
?
6
IL6  
?
5
IL5  
?
4
IL4  
?
3
IL3  
?
2
IL2  
?
1
IL1  
?
0
IL0  
?
Reset  
Bit  
Name  
IL{n}  
Description  
{n}  
Interrupt level n (where n = 0 through 31).  
0 – Interrupt routed to CPU IRQ interrupt input.  
1 – Interrupt routed to CPU FIQ interrupt input.  
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System Control Module  
9.2.1.5  
Interrupt Controller Control Register (ICCR)  
The interrupt controller control register (ICCR) contains a single control bit, the disable idle mask  
bit (DIM). When set, this bit inhibits the idle mode operation where the output of the ICMR is  
OR’ed to all ones. If this bit is set, then the interrupts that are capable of bringing the SA-1100 out  
of idle mode are defined by the contents of the ICMR. The following table shows the location of all  
interrupt level bits in the ICCR.  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
Bit  
R/W  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
0
9
8
Reserved  
0
7
6
5
4
3
2
1
0
DIM  
0
Reset  
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
{0}  
DIM  
Disable idle mask.  
0 – All enabled interrupts will bring the SA-1100 out of idle mode.  
1 – Only enabled and unmasked (as defined in the ICMR) will bring the SA-1100 out of  
idle mode. This bit is cleared during all resets.  
1..31  
Reserved.  
9-16  
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System Control Module  
9.2.2  
Interrupt Controller Register Locations  
The following table shows the registers associated with the interrupt controller block and the  
physical addresses used to access them.  
Address  
0h 9005 0000  
Name  
ICIP  
Description  
Interrupt controller IRQ pending register  
Interrupt controller mask register  
Interrupt controller level register  
0h 9005 0004  
0h 9005 0008  
0h 9005 0010  
0h 9005 0020  
0h 9005 000C  
ICMR  
ICLR  
ICFP  
ICPR  
ICCR  
Interrupt controller FIQ pending register  
Interrupt controller pending register  
Interrupt controller control register  
9.3  
Real-Time Clock  
The SA-1100 contains a real-time clock (RTC) that provides a general-purpose real-time reference  
for use by the system. The RTC is uninitialized after a hardware reset (nRESET) and must be  
written by the user to the desired value. Thereafter, the counter will remain valid until another  
hardware reset (assumed to be infrequent). The value of the counter is unaffected by transitions  
into and out of sleep, idle, software reset, or a watchdog reset. The counter is incremented on rising  
edges of the 1-Hz clock.  
In addition to the counter [ RTC counter register (RCNR) ], the RTC incorporates a 32-bit alarm  
register (RTAR). The RTAR may be programmed with a value to be compared against the counter.  
On each rising edge of the 1-Hz clock, the counter is incremented and then compared to the RTAR.  
If the values match, then a status bit is set. This status bit is also routed to the interrupt controller  
and may be programmed to generate a CPU interrupt.  
Another interruptible status bit is available that is set whenever the 1 Hz clock ticks. Each status bit  
may be cleared by writing a one to the status register in the desired bit position. The 1-Hz clock is  
generated by dividing down the 32.768-kHz crystal oscillator output. This divider logic is  
programmable to allow the user to “trim” the counter to adjust for inherent inaccuracies in the  
crystal’s frequency. This trimming mechanism permits the user to adjust the RTC to an accuracy of  
+/- 5 seconds per month. The trimming procedure is described later in this section.  
9.3.1  
RTC Counter Register (RCNR)  
The RTC counter register (RCNR) is a read/write register and is not cleared by any reset source.  
The counter may be written by the processor at any time although it is recommended that the  
operating system prevent inadvertent writes to the RCNR through the use of the MMU protection  
mechanisms.  
Because of the asynchronous nature of the 1-Hz clock relative to the processor clock, writes to this  
counter are controlled by a hardware mechanism that delays the actual write to the counter by up to  
one 32-kHz-clock (~ 30 µs) after the processor store is performed.  
After the processor writes to the RCNR, all other writes to this register location are ignored until  
the new value is actually loaded into the counter. The RCNR may be read at any time. Reads reflect  
the value in the counter immediately after it increments or loads.  
SA-1100 Developer’s Manual  
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System Control Module  
9.3.2  
RTC Alarm Register (RTAR)  
The real-time clock alarm register is a 32-bit register that is readable and writable by the processor.  
Following each rising edge of the 1-Hz clock, this register is compared to the RCNR. If the two are  
equal and the enable bit is set, then the alarm bit in the RTC status register is set. The value in this  
register is undefined after the assertion of nRESET.  
9.3.3  
RTC Status Register (RTSR)  
The following table shows the location of all bits in the RTSR. All reserved bits are read as zeros  
and are unaffected by writes; a question mark indicates that the value is unknown at reset. The AL  
and HZ bits in this register are routed to the interrupt controller where they may be enabled to  
cause an interrupt. The AL and HZ bits are cleared by writing ones to them.  
.
Bit  
R/W  
Reset  
0
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
0
8
0
Bit  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
9
7
6
5
4
3
HZE  
?
2
ALE  
?
1
HZ  
?
0
AL  
?
R/W  
Reset  
Reserved  
0
0
0
0
0
0
Bit  
Name  
Description  
0
1
2
3
AL  
RTC alarm detected.  
0 – No alarm has been detected.  
1 – An alarm has been detected (RTNR matches RCAR).  
HZ  
1-Hz rising-edge detected.  
0 – No rising edge has been detected.  
1– A rising edge has been detected.  
ALE  
HZE  
RTC alarm interrupt enable.  
0 – The RTC alarm interrupt is not enabled.  
1 – The RTC alarm interrupt is enabled.  
1-Hz interrupt enable.  
0 – The 1-Hz interrupt is not enabled.  
1 – The 1-Hz interrupt is enabled.  
31..4  
Reserved.  
9-18  
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System Control Module  
9.3.4  
RTC Trim Register (RTTR)  
The RTTR is programmed by the user to select the frequency of the 1-Hz clock. If this register is  
not programmed and left at its reset value (all zeros), then the 1-Hz clock will actually be running  
at 32.768 kHz. See the following section for details on how to calculate the value in this register.  
The following table shows the location of all bits in the RTTR. All reserved bits are read as zeros  
and are unaffected by writes.  
.
Bit  
R/W  
Reset  
0
31  
0
30  
0
29  
28  
0
27  
0
26  
0
25  
D9  
0
24  
D8  
0
23  
D7  
0
22  
D6  
0
21  
D5  
0
20  
D4  
0
19  
D3  
0
18  
D2  
0
17  
D1  
0
16  
D0  
0
Reserved  
0
Bit  
15  
C15  
0
14  
C14  
0
13  
C13  
0
12  
C12  
0
11  
C11  
0
10  
C10  
0
9
C9  
0
8
C8  
0
7
C7  
0
6
C6  
0
5
C5  
0
4
C4  
0
3
C3  
0
2
C2  
0
1
C1  
0
0
C0  
0
R/W  
Reset  
Bit  
Name  
C0-C15  
Description  
0..15  
Clock divider count.  
This value is the integer portion of the clock trim logic.  
Trim delete count.  
16..25 D0-9  
This value represents the number of 32-kHz clocks to delete when clock trimming  
begins.  
26..31  
Reserved.  
9.3.5  
Trim Procedure  
The 1-Hz clock feeding the RTC is obtained by dividing the output of the 32.768-kHz oscillator  
down. Since 32768 is a power of two, a 15-bit divider will generate a 1-Hz clock (given a perfect  
crystal and perfect board environment). The inherent inaccuracies of crystals, aggravated by  
varying capacitance of the board connections, and so on, cause the timebase to be somewhat  
inaccurate, requiring a periodic adjustment in the 1 Hz clock period. The SA-1100, through the  
RTTR, allows the user to adjust or "trim" the 1 Hz timebase to an accuracy of +/- 5 seconds per  
month. At reset, the RTTR contains zeros that disable the trim circuitry. When the trim circuitry is  
disabled, the 1-Hz clock feeding the RTC is the same frequency as the output of the 32.768-kHz  
oscillator. The RTTR is reset to all zeros each time the nRESET signal is asserted.  
9.3.5.1  
Oscillator Frequency Calibration  
To generate the value to be entered into the RTTR, the user must first measure the output frequency  
of the 32.768-kHz oscillator using an accurate timebase, such as a frequency counter. This clock is  
made externally visible by selecting the alternate function for GPIO<27>. To gain access to the  
clock, this pin must be programmed as an output and then switched over to the alternate function.  
See the Section 9.1, “General-Purpose I/O” on page 9-1 in this chapter for details on how to gain  
access to the clock. The trim is accomplished by dividing the output of the oscillator by an integer  
value and then doing fine-grain fractional adjustment by periodically deleting clocks from the  
stream feeding this integer divider.  
SA-1100 Developer’s Manual  
9-19  
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System Control Module  
9.3.5.2  
RTTR Value Calculations  
After the true frequency of the oscillator is known, it must be split into integer and fractional  
portions. The integer portion of the value (minus one) is loaded into the C0-C15 field of the RTTR.  
This value is compared against a 16-bit counter clocked by the output of the 32.768-kHz oscillator.  
The counter resets and generates a pulse when the two values are equal. This pulse constitutes the  
raw 1-Hz signal.  
The fractional part of the adjustment is done by periodically deleting clocks from the clock stream  
feeding the integer counter. The period, called the "trim interval," is hardwired to be 210 -1 seconds  
(approximately 17 minutes). The number of clocks deleted, called the "trim delete value," is a  
10-bit programmable counter allowing from 0 to 210 -1 32-kHz clocks to be deleted from the input  
clock stream once per trim interval. D0-D9 represents the number of clocks deleted per trim  
operation. In summary, every 210 -1 seconds, the integer counter stops clocking for a period equal  
to the fractional error that has accumulated. If this counter is programmed to a zero (as it is at a  
hard reset), then no trim operations will occur and the RTC will be clocked with the raw  
32.768-kHz clock. The relationship between the nominal 1-Hz clock frequency and the nominal  
32.768-kHz clock (f1 and f32K respectively) is shown in the following equation.  
f32k  
(2^10-1)*(C<15..0> +1) -D<9..0>  
f1=  
*
(C<15..0> +1)  
(2^10-1)*(C<15..0> +1)  
Trim Example #1 – Measured Value Has No Fractional Component  
In this example, the oscillator output is measured to be 36045.000 cycles/s (Hz). This output is  
exactly 3277 cycles over the nominal frequency of the crystal and has no fractional component. As  
such, only the integer trim function is needed and no fractional trim is required. Accordingly, the  
C0-C15 field of the RTTR is loaded with the binary equivalent of 36045-1, or 0x8CCC. The  
D0-D9 field is left at zero (power-up state) to disable fractional trimming. This trim exercise leaves  
an error of zero in trimming.  
Trim Example #2 – Measured Value Has a Fractional Component  
This example is a more common case in that the measured frequency of the oscillator has a  
fractional component. If the oscillator output is measured to be 32768.92 cycles/s (Hz), an integer  
trim is necessary so that the average number of cycles counted before generating one 1-Hz clock is  
32768.92. Similar to the previous example, the integer field D0-D15 is loaded with the  
hexadecimal equivalent of 32768-1 or 0x7FFF.  
Because the actual clock frequency is 0.92 cycles per second faster than the integer value, the 1-Hz  
clock generated by just the integer trimming is slightly faster than needed and must be slowed  
down. Accordingly, the fractional trim must be programmed to delete 0.92 cycles per second on  
average to bring the 1-Hz output frequency down to the proper value. Since the trimming  
procedure is performed only every 210-1=1023 seconds, the trim must be set to delete (.92*1023)  
= 941.16 clocks every 1023 seconds. The fractional component of this value cannot be trimmed  
out and constitutes the error in trimming, described below. The counter should be loaded with the  
hexadecimal equivalent of 941, or 0x3AD.  
9-20  
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System Control Module  
This trim setting leaves an error of .16 cycles per 1023 seconds. The error calculation yields (in  
parts-per-million or ppm):  
0.16 cycles  
1023 sec 32768 cycles  
1 sec  
Error = --------------------------X------------------------------ = 0 . 0 0 2 p p m  
Maximum Error Calculation Versus Real-Time Clock Accuracy  
As seen from trim example #2, the maximum possible error approaches 1 clock per 210-1 seconds.  
Calculating the ppm error for this scenario yields:  
1 cycle  
1023 sec 32768 cycles  
1 sec  
Error (maximum) = --------------------X------------------------------ = 0 . 0 3 p p m  
To maintain an accuracy of +/- 5 seconds per month, the required accuracy is calculated to be:  
5 sec  
1 month  
Error = --------------X----------------------------- = 1.9 ppm  
month 2592000 sec  
This calculation indicates that the accuracy of the SA-1100 trim mechanism is more than adequate  
to compensate for the static environmental and manufacturing variables, and still provides  
acceptable accuracy.  
9.3.6  
Real-Time Clock Register Locations  
The following table describes the real-time clock registers.  
Address  
0h 9001 0004  
Name  
RCNR  
Description  
RTC count register  
RTC alarm register  
RTC status register  
RTC timer trim register  
0h 9001 0000  
0h 9001 0010  
0h 9001 0008  
RTAR  
RTSR  
RTTR  
9.4  
Operating System Timer  
The SA-1100 contains a 32-bit operating system timer that is clocked by the 3.6864-MHz oscillator.  
The operating system count register (OSCR) is a free-running up-counter that is not cleared during  
any reset (contains unknown value after reset). The OS timer also contains four 32-bit match registers  
(OSMR<3:0>). Each register can be written and read by the user. When the value in the OSCR  
matches (is equal to) the value within any of the match registers, and the interrupt enable bit is set, the  
corresponding bit in the OSSR is set. These bits are also routed to the interrupt controller where they  
can be programmed to cause an interrupt. OSMR<3> also serves as a watchdog match register that  
resets the SA-1100 when a match occurs. The only register that is reset to a known state is the  
watchdog match enable register (WMER). The user must initialize all other registers and clear any set  
status bits before the FIQ and IRQ interrupts are enabled within the CPU.  
SA-1100 Developer’s Manual  
9-21  
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System Control Module  
9.4.1  
9.4.2  
OS Timer Count Register (OSCR)  
The OS timer count register is a 32-bit counter that increments on rising edges of the 3.6864-MHz  
clock. This counter can be read or written at any time. It is recommended that the system  
write-protect this register through the MMU protection mechanisms.  
OS Timer Match Registers 0–3 (OSMR<0>, OSMR<1>,  
OSMR<2>, OSMR<3>)  
These registers are 32 bits wide and are readable and writable by the processor. They are compared  
against the OSCR following every rising edge of the 3.6864-MHz clock. If any of these registers  
match the counter at this time, then the corresponding status bit in the OSSR is set. The status bits  
are routed to the interrupt controller where they can be unmasked to cause a CPU interrupt.  
OSMR<3> may also serve as a watchdog timer. See the Section 9.4.6, “Watchdog Timer” on  
page 9-24 for operation information.  
9.4.3  
OS Timer Watchdog Match Enable Register (OWER)  
The watchdog enable register contains a single control bit (bit 0) that enables the watchdog  
function. This bit is set by writing a one to it. It can only be cleared by one of the reset functions  
(hardware reset, software reset) and by entering sleep mode. A watchdog reset also clears the  
watchdog enable bit. The format of this register follows:  
.
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
Bit  
R/W  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
0
9
8
Reserved  
0
7
6
5
4
3
2
1
0
WME  
0
Reset  
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
0
WME  
Watchdog match enable.  
0 – OS timer match register<3> matches cause an interrupt request.  
1 – OS timer match register<3> matches cause a reset of the SA-1100.  
Note: This is a write-once bit that once written, can only be changed after a hardware  
(pin), software (SWR), or sleep mode reset.  
31..1  
Reserved.  
9-22  
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System Control Module  
9.4.4  
OS Timer Status Register (OSSR)  
This status register contains status bits indicating whether a match has occurred on any of the four  
match registers. These bits are set when the event occurs (following the rising edge of the  
3.6864-MHz clock) and cleared by writing a one to the proper bit position. Writing zeros to this  
register has no effect. All reserved bits read as zeros and are unaffected by writes; a question mark  
indicates that the value is unknown at reset.  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
8
0
Bit  
R/W  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
9
7
6
5
4
3
M3  
?
2
M2  
?
1
M1  
?
0
M0  
?
Reserved  
Reset  
0
0
0
0
0
0
Bit  
Name  
Description  
0
1
2
3
M0  
M1  
M2  
M3  
Match status channel 0.  
0 – OS timer match register<0> has not matched the OS timer counter since the last  
clear.  
1 – OS timer match register<0> has matched the OS timer counter.  
Match status channel 1.  
0 – OS timer match register<1> has not matched the OS timer counter since the last  
clear.  
1 – OS timer match register<1> has matched the OS timer counter.  
Match status channel 2.  
0 – OS timer match register<2> has not matched the OS timer counter since the last  
clear.  
1 – OS timer match register<2> has matched the OS timer counter.  
Match status channel 3.  
0 – OS timer match register<3> has not matched the OS timer counter since the last  
clear.  
1 – OS timer match register<3> has matched the OS timer counter.  
Reserved.  
31..4  
SA-1100 Developer’s Manual  
9-23  
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9.4.5  
OS Timer Interrupt Enable Register (OIER)  
This register contains four enable bits indicating whether a match between one of the match  
registers and the OS timer counter will set a status bit in the OSSR. Each match register has a  
corresponding enable bit. Clearing an enable bit does not clear the corresponding interrupt status  
bit if that bit is already set.  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
8
0
Bit  
R/W  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
9
7
6
5
4
3
E3  
0
2
E2  
0
1
E1  
0
0
E0  
0
Reserved  
Reset  
0
0
0
0
0
0
Bit  
Name  
Description  
0
1
2
3
E0  
E1  
E2  
E3  
Interrupt enable channel 0.  
This bit is set by software and allows a match between match register 0 and the OS timer  
to assert interrupt bit M0 in the OSSR.  
Interrupt enable channel 1.  
This bit is set by software and allows a match between match register OSMR[1] and the  
OS timer to assert interrupt bit M1 in the OSSR.  
Interrupt enable channel 2.  
This bit is set by software and allows a match between match register OSMR[2] and the  
OS timer to assert interrupt bit M2 in the OSSR.  
Interrupt enable channel 3.  
This bit is set by software and allows a match between match register OSMR[3] and the  
OS timer to assert interrupt bit M3 in the OSSR.  
31..4  
Reserved.  
9.4.6  
Watchdog Timer  
OSMR<3> may also serve as a watchdog compare register. This function is enabled by setting bit 0  
in the OWER. When a compare against this register occurs when the watchdog is enabled, reset is  
applied to the SA-1100 and most internal states are cleared (with exceptions listed below). Internal  
reset is asserted for 256 processor clocks and then removed, allowing the SA-1100 to boot. Units  
that do not receive this internal reset are: the power manager, the refresh timer, and the PLL  
configuration. Watchdog reset affects the SA-1100 similar to a software reset. See the Section 9.6,  
“Reset Controller” on page 9-41 for details on what is affected by each kind of reset. When the  
SA-1100 comes out of a watchdog reset, a bit is set in the reset controller status register (RCSR) to  
indicate that the event happened.  
The following procedure is suggested when using OSMR<3> as a watchdog: each time the  
operating system services the register, the current value of the counter is read, and a number is then  
added to the value read, corresponding to the amount of time before the next timeout (care must be  
taken to account for counter wraparound). This number is then written back to OSMR<3>. The OS  
code must repeat this procedure periodically before each match occurs. If the match occurs, the OS  
timer will assert a reset.  
9-24  
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9.4.7  
OS Timer Register Locations  
Table 9-1 shows the registers associated with the OS timer and the physical addresses used to  
access them.  
Table 9-1.  
OS Timer Register Locations  
Address  
Name  
Description  
OS timer match registers<3:0>  
0h 9000 0000  
0h 9000 0004  
0h 9000 0008  
OSMR<0>  
OSMR<1>  
OSMR<2>  
0h 9000 000C  
OSMR<3>  
0h 9000 0010  
0h 9000 0014  
0h 9000 0018  
0h 9000 001C  
OSCR  
OSSR  
OWER  
OIER  
OS timer counter register  
OS timer status register  
OS timer watchdog enable register  
OS timer interrupt enable register  
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9.5  
Power Manager  
The SA-1100 contains power management logic that controls the transition between three different  
modes of operation: run, idle, and sleep. These modes are used to reduce processor power  
consumption at times when some functions are not needed, or when the system’s power supply is  
low or out of regulation. Each of the respective modes is associated with a reduced level of power  
consumption. Idle mode is entered via software. Sleep mode is entered either via software or by  
asserting one of two input pins that indicate a power supply fault. Idle mode is exited through an  
interrupt. Sleep mode is exited through a preprogrammed wake-up condition. Both modes may be  
exited in extreme cases via hardware reset. If none of the power management modes is active and  
the SA-1100 is out of reset, then it is said to be in run mode.  
9.5.1  
9.5.2  
Run Mode  
Run mode is the normal operating mode of the SA-1100: all power supplies are enabled, all clocks  
are running, and every on-chip resource is functional. This is the normal state of operation for the  
processor while it is executing code. Under usual conditions, the processor enters run mode after  
successful power-up and reset of the part.  
Idle Mode  
Idle mode allows a software application to stop the CPU when not in use, while continuing to  
monitor interrupt service requests both on or off-chip. When an interrupt occurs, the CPU is  
reactivated. During idle mode, the SCM, PM, and MPCM are each fully operational.  
In idle mode, the CPU clock is stopped. Since the SA-1100 is static, all CPU state information is  
saved. This allows the part to be switched back to run mode, starting operation exactly where it left  
off. During idle mode, all other on-chip resources are active, including: all system unit modules  
(real-time clock, operating system timer, interrupt controller, general-purpose I/O, and power  
manager); all peripheral unit modules (DMA controller, LCD controller, serial controller 0-4); and  
all memory controller resources. The PLL also remains in lock so that the part can be brought out  
of idle mode quickly when an interrupt occurs.  
9.5.2.1  
Entering Idle Mode  
Idle mode is entered while in run mode by executing a three instruction sequence consisting of the  
privileged on-chip coprocessor 15 instruction ‘disable clock switching’, a load from a  
noncacheable memory location (C=B=0), and the privileged on-chip coprocessor 15 instruction  
‘wait for interrupt’. This sequence must reside in the first three words of an instruction cache line,  
which requires that the linker align the idle mode instruction sequence on an eight word boundary.  
Idle mode is entered by following the exact code sequence:  
AREA Idle$$Code , CODE, READONLY, ALIGN=5  
;Aligned to 8 word boundary  
;p15 = coprocessor 15  
;r0 = register 0 (contents not used)  
;c15 = test, clk, and idle cntl register  
;c2 = CRm = 0b0010  
mcr p15, 0, r0, c15, c2, 2  
ldr r0, <r1>  
;2 = OPC_2 = 0b010  
;<r1> points to non-cachable mem loc  
;c8 = CRm = 0b1000  
mcr p15, 0, r0, c15, c8, 2  
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9.5.2.2  
Exiting Idle Mode  
Any enabled interrupt from the system unit or peripheral unit will cause a transition from idle mode  
back to run mode. Note that the interrupt controller (ICMR) mask register is ignored during idle  
mode, meaning that an interrupt does not need to be unmasked to bring the SA-1100 out of idle.  
When an interrupt occurs, the CPU clocks are reactivated, the wait for interrupt instruction is  
completed, and run program flow resumes.  
A transition from idle to run mode can also occur by asserting the nRESET pin or if OSMR<3> is  
configured as a watchdog and a match occurs that causes the assertion of reset. Since the watchdog  
timer (if enabled) is functional during idle, care must be taken to set the watchdog match register  
far enough in advance to ensure that another interrupt is guaranteed to bring the SA-1100 out of  
idle before the watchdog reset occurs. It is recommended that either an RTC alarm or another OS  
timer channel be used for this purpose.  
When in idle mode, if the BATT_FAULT and/or VDD_FAULT pins are asserted, the SA-1100  
enters sleep mode.  
9.5.3  
Sleep Mode  
Sleep mode offers the greatest power savings to the user and consequently the lowest level of  
available functionality. In the transition from run or idle to sleep mode, the SA-1100 performs an  
orderly shutdown of on-chip activity, applies an internal reset to the processor, and then negates the  
PWR_EN pin indicating to the external system that the VDDI (1.5-V supply) should be driven to  
zero volts. Internally, this switches off the power to the majority of the processor at this time. (The  
VDDX I/O voltage supply must remain powered during sleep.) Running off the 32.768-kHz crystal  
oscillator, the sleep state machine watches for a preprogrammed wake-up event to occur, after  
which it asserts PWR_EN (to reestablish the VDDI power supply), and steps through an orderly  
wake-up sequence. When the power supply and clocks are stable, the power manager brings the  
SA-1100 out of reset. Status bits in the reset controller status register (RCSR) may be read to  
indicate to software that the reset was due to sleep mode.  
9.5.3.1  
9.5.3.2  
CPU Preparation for Sleep Mode  
In preparation for sleep mode, software should initialize the power manager GPIO sleep state  
register (PGSR) and the power manager wake-up enable register (PWER). Also, the GPIO  
falling-edge detect and GPIO rising-edge detect enable registers (GFER and GRER) should be  
written with the appropriate values. The OPDE bit in the power manager configuration register  
(PCFR) should also be programmed with the desired value.  
Events Causing Entry into Sleep Mode  
Sleep mode can be entered in one of two ways: via software or a power supply fault. Entry into  
sleep mode via software is accomplished by setting the force sleep bit in the power manager  
control register (PMCR). This bit is set by software and cleared by hardware during sleep. When  
the SA-1100 wakes up from sleep, this bit is already cleared.  
Entry into sleep via a power supply fault is caused by the assertion of either the VDD_FAULT or  
BATT_FAULT pins. The VDD_FAULT pin should be used to indicate that the main power supply  
is out of regulation. The BATT_FAULT pin should be used to indicate that the battery has been  
removed or is low. These pins have identical operation for the purpose of entering sleep mode.  
They have different implications during the wake-up sequence as described in the following  
section.  
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9.5.3.3  
The Sleep Shutdown Sequence  
The sleep state machine begins the shutdown sequence. This sequence consists of three steps.  
In the first step, the following actions occur:  
a. Power manager switches the GPIO output pins to their sleep state. This sleep state is  
programmed in advance by loading the power manager GPIO sleep state register (PGSR)  
into the GPIO output data register. (See the Section 9.1, “General-Purpose I/O” on  
b. The DRAMs are placed into self-refresh mode. The memory controller finishes whatever  
memory operation might be in progress and then drives the RAS<3:0> and CAS<3:0>  
pins low.  
c. If the sleep sequence was entered due to the assertion of VDD_FAULT or BATT_FAULT,  
the possible wake-up sources are reset from what was programmed by software to their  
"fault state". The fault state is to allow a transition only on GP<0> and GP<1> to act as a  
wake-up event.  
In the second step of sleep shutdown, the following actions occur:  
a. All potential wake-up sources are cleared. This involves clearing all the GPIO edge detect  
status bits and clearing the RTC alarm interrupt bit. These bits are cleared to prevent latent  
status bits from causing an immediate wake-up. This functionality is provided to cover the  
situation of entering sleep due to a power fault because the CPU does not have the ability  
to prepare for the entry into sleep.  
b. An internal reset is applied to the SA-1100. All units are reset and the RESET_OUT pin is  
asserted.  
In the third step of sleep shutdown, the following actions occur:  
a. The 3.686-MHz oscillator is stopped. This action is dependent on the state of the  
oscillator power-down enable bit (OPDE) in the power manager configuration register  
(PCFR). If this bit is set, then the oscillator is stopped during sleep, resulting in greater  
power savings. If the bit is cleared (the power-on reset state), then the oscillator continues  
to run during sleep and results in a faster wake-up sequence.  
b. The PWR_EN pin is negated. The external system must respond to this negation by  
disabling the VDDI power supply. In contrast to the SA-110, the SA-1100 systems are not  
required to drive VDDI to zero volts in sleep. However, the power supply should be  
disabled to prevent power consumption.  
Each step in the sleep shutdown sequence takes one cycle of the 32.768-kHz clock  
(~30 microseconds).  
9.5.3.4  
9.5.3.5  
During Sleep Mode  
During sleep mode, the SA-1100 watches for preprogrammed wake-up events. These events are  
either programmed by the CPU prior to setting the force sleep bit or by the power manager when a  
fault condition is detected.  
The Sleep Wake-Up Sequence  
When a valid wake-up event is detected and there is no BATT_FAULT, the SA-1100 begins a  
wake-up sequence. If BATT_FAULT is asserted, then the wake-up event is ignored. VDD_FAULT  
is always ignored at this time because the VDDI supply is disabled at this time. The wake-up  
sequence occurs in three steps.  
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In the first step of the wake-up sequence, the following actions occur:  
a. The PWR_EN pin is asserted, indicating that the external supply must apply power on the  
VDDI pins.  
b. An internal timer begins to time the power ramp. This timer waits for approximately  
10 ms.  
c. The 3.686-MHz oscillator is enabled for operation if it was originally programmed to be  
disabled.  
d. If BATT_FAULT is asserted at any time during the sleep wake-up sequence, the power  
manager transitions back to sleep mode through the fault state.  
In the second step of the wake-up sequence (after the power ramp timer has expired), the  
following actions occur:  
a. A second internal timer begins to time the 3.686-MHz oscillator as it begins to ramp up to  
speed. This timer waits for 150 ms. If the OPDE bit in the PCFR is zero, then the  
oscillator was never disabled and this timer is not used. In this case, the power manager  
transitions to the third step directly without waiting for the oscillator timer to complete.  
b. If BATT_FAULT or VDD_FAULT is asserted at any time during the oscillator ramp, the  
power manager transitions back to sleep mode through the fault state.  
In the third step of the wake-up sequence (after the 3.6864-MHz oscillator is stabilized), the  
following actions occur:  
a. The SA-1100 internal reset is negated and the CPU begins a normal boot sequence.  
b. The RESET_OUT pin is negated, indicating that the SA-1100 is about to perform a fetch  
from the reset vector location.  
During the fault state entered through the assertion of VDD_FAULT or BATT_FAULT, the  
following actions occur:  
All potential wake-up sources are cleared (all GPIO edge detects and the RTC alarm interrupt).  
The power manager wake-up source register (PWER) is loaded with 0x0000 0003 and bits 0  
and 1 of the GFER and the GRER (see the Section 9.1, “General-Purpose I/O” on page 9-1)  
are set. This limits the potential wake-up sources to a rising or falling edge on GP<0> or  
GP<1>. This wake-up fault state is provided to prevent spurious events from causing an  
unwanted wake-up during a low battery or shorted power supply situation. This fault state  
setting of PWER, GRER, and GFER registers is also the default state of the registers after a  
hardware reset.  
9.5.3.6  
Booting After Sleep Mode  
When the SA-1100 boots after sleep mode (or at any other time), it must examine the reset  
controller status register (RCSR) to determine why it just booted. This register has bits to indicate  
sleep reset, software reset, watchdog reset, or hardware reset (assertion of nRESET). See the  
Next, software should examine the power manager sleep status register (PSSR) to determine why it  
was in sleep. This register has bits to indicate whether a VDD_FAULT, BATT_FAULT, or force  
sleep bit has been asserted since the register was last cleared. It is possible for multiple bits to be set  
in this register.  
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System Control Module  
Also, the SA-1100 provides the power manager scratchpad register (PSPR) for saving any general  
processor state during sleep. This register may be written by the processor and the contents will  
survive sleep mode. The bits in this register are not explicitly used by the SA-1100, but may be  
used by software to index into ROM space to retrieve memory controller configuration, for  
example.  
Note: The nRESET pin must not be asserted during sleep mode if the DRAM contents are to be  
preserved. The assertion and subsequent negation of nRESET during sleep mode causes the  
SA-1100 to clear the FS bit in the force sleep register, assert PWR_EN, time the PLL lock  
sequence, and subsequently negate the internal reset signal. This causes the SA-1100 to perform a  
normal boot sequence because all information about the previous sleep state is lost.  
9.5.3.7  
Reviving the DRAMs from Self-Refresh Mode  
Because the DRAMs are placed in self refresh prior to the sleep mode shutdown, their contents are  
preserved during sleep. After exiting sleep, software must reconfigure the DRAM control registers,  
which lost power during sleep mode, and then take the DRAMs out of self-refresh mode. Clearing  
the DRAM hold (DH) bit in the power management status register (PMSR) will cause the  
RAS<3:0> and CAS<3:0> pins to return to the negated state (high) in preparation for a DRAM  
access.  
9.5.4  
9.5.5  
Notes on Power Supply Sequencing  
On the SA-1100, as on the SA-110, it is important that VDDX (3.3 V nominal) power-up occur  
before VDDI (1.5 V nominal). One approach to ensuring this sequencing is to power the 1.5-V  
supply using the 3.3-V supply. On the SA-1100, a second simple option is available. If the  
PWR_EN output is used to enable the 1.5-V supply, the SA-1100 will enforce the required  
sequencing by holding PWR_EN deasserted until the 3.3-V supply is sufficiently high.  
Assumed Behavior of an SA-1100 System in Sleep Mode  
The assumed model of an SA-1100 system in sleep mode is one in which the system is relatively  
quiet. In particular, there should be no gratuitous switching on of the SA-1100 input pins. Although  
there will be some switching in GPIOs to bring the processor out of sleep and potentially on the  
VDD_FAULT and BATT_FAULT pins, the switching is a low-frequency activity and usually  
brings the SA-1100 out of sleep mode.  
The major concern is for power dissipation in sleep and requirements for the power supplies on the  
processor during sleep. The SA-1100 generates these supplies using several on-chip regulators with  
limited current capacity. Excessive activity on-chip pins might load these regulators beyond their  
capacity and result in droop of the on-chip supplies. One example is that of a component tied to one  
of the GPIO pins that constantly transmits to the processor. If the system design indicated that  
activity from this detector should not bring the SA-1100 out of sleep, the transitions from this  
GPIO might result in switching in the processor that would exceed the sleep current limit. This  
concern exists regardless of whether the GPIO is enabled as a wake-up source.  
Figure 9-3 shows the three power-related modes of the SA-1100 and the actions that cause  
transitions between the modes. Table 9-2 summarizes what power and clock supplies are used by  
each module within the SA-1100, as well as the status of the power and clock supplies to each unit  
during each of the three power-related modes.  
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Figure 9-3. Transitions Between Modes of Operation  
Power on, nRESET asserted  
HARDWARE RESET  
nRESET asserted  
nRESET asserted  
nRESET negated  
RUN  
Wait for interrupt  
instruction  
Force sleep bit set, or VDD or  
battery fault pins asserted  
System or  
peripheral unit  
interrupt  
GPIO or RTC  
alarm interrupt  
IDLE  
SLEEP  
VDD or battery fault  
pins asserted  
CPU clock held low; all  
other resources active, wait  
for interrupt  
Wait for wake-up  
event  
Table 9-2.  
SA-1100 Power and Clock Supply Sources and States During Power-Down Modes  
Power Management Mode  
Supply Source  
Run  
Idle  
Sleep  
Module  
Pwr  
Clk  
Pwr  
Clk  
Pwr  
Clk  
Pwr  
Clk  
CPU  
MMUs (I&D)  
Write buffer  
Read buffer  
JTAG  
Stopped  
VDD  
Stopped  
3.6864  
MHz  
Disabled  
OS timer  
LCD controller  
Serial channel 0-4  
On  
Running  
On  
Memory and  
PCMCIA  
control  
Running  
Real-time clock  
Interrupt  
Running  
controller  
On  
32.768  
kHz  
VDDX  
Power manager  
General-purpose I/O  
Pin pads  
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9.5.6  
Pin Operation in Sleep Mode  
The SA-1100 pins are categorized by the following types based on their behavior during sleep mode:  
Type 1 – These pins are outputs and are driven low during sleep. These pins hold their state after  
sleep mode is exited until the DRAM_control_hold bit in the PSSR is cleared.  
Type 2 – These pins are outputs and are normally driven to a one in sleep. To support systems that  
power down external devices, these pins can also be tristated in sleep through the use of the  
FLOAT_STATIC and FLOAT_PCMCIA bits in the PCFR. See the Section 9.5, “Power Manager”  
Type 3 – These pins are I/Os. When programmed as outputs, they can be actively held high or low  
during sleep. When programmed as inputs, they are actively sampled by the SA-1100.  
Type 4 – These pins are I/Os but become inputs during sleep. They can be programmed to hold the pin  
state at a zero or can be tristated. The receivers on these pins are disabled during sleep. These pins hold  
their state after sleep mode is exited until the peripheral_control_hold bit in the PSSR is cleared.  
Type 5 – These pins are outputs and are actively driven during sleep.  
Type 6 – These pins are outputs and are tristated during sleep.  
Type 7 – These pins are inputs and are actively sampled during sleep.  
Type 8 – These pins are inputs and are not observed during sleep; the receiver is disabled.  
Type 9 – These pins are analog inputs and outputs, and are always active.  
Table 9-3.  
Pin State During Step  
Pin Name  
A<25:0>  
Type  
Pin Name  
nPREG  
Type  
Pin Name  
RXD_2  
Type  
Pin Name  
Type  
1
1
4
nRESET_OUT  
nTRST  
TDI  
1
D<31:0>  
nCS<3:0>  
nOE  
1
2
2
2
1
1
2
2
2
2
2
1
L_DD<7:0>  
L_FCLK  
L_BIAS  
TXD_C  
RXD_C  
SCLK_C  
SFRM_C  
UDC+  
4
4
4
4
4
4
4
4
4
4
4
4
TXD_3  
4
4
3
8
9
9
9
9
5
7
7
7
8
RXD_3  
8
GP<27:0>  
ROM_SEL  
PXTAL  
TDO  
6
nWE  
TMS  
8
nRAS<3:0>  
nCAS<3:0>  
nPIOW  
TCK  
8
PEXTAL  
TXTAL  
TCK_BYP  
TESTCLK  
VDD  
7
7
nPIOR  
TEXTAL  
nPCE<2:1>  
nIOIS16  
nPWAIT  
PSKTSEL  
UDC-  
PWR_EN  
BATT_FAULT  
VDD_FAULT  
nRESET  
VDDX  
VSS  
TXD_1  
RXD_1  
TXD_2  
VSSX  
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9.5.7  
Power Manager Registers  
The power manager is controlled through eight 32-bit registers. The power manager control  
register (PMCR) is used to allow software invocation of sleep mode. The sleep status register  
(PSSR) contains status bits that indicate why sleep mode was invoked. The power manager  
scratchpad register (PSPR) is a general-purpose register used to store processor data during sleep.  
The power manager wake-up enable register (PWER) is used to program the desired wake-up  
sources in the system. The power manager general configuration register (PCFR) contains bits  
used to control various configurable functions within the SA-1100. The power manager PLL  
configuration register (PPCR) allows the user to change the PLL operating frequency. The power  
manager GPIO sleep state register (PGSR) is used to program the value loaded onto GPIO outputs  
when the SA-1100 transitions into sleep mode. The power manager oscillator status register  
(POSR) contains a single bit that indicates whether the 32.768-kHz oscillator has stabilized after a  
hardware reset.  
9.5.7.1  
Power Manager Control Register (PMCR)  
Sleep mode is invoked by setting the force bit within the power manager control register (PMCR).  
The force bit is automatically cleared upon exiting sleep mode or when a hardware reset occurs.  
Writing zero to the force bit has no effect. For reserved bits, writes are ignored and reads return  
zero. This register should be protected by programming MMU permissions. The following table  
shows the PMCR.  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
Bit  
R/W  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
0
9
8
Reserved  
0
7
6
5
4
3
2
1
0
SF  
0
Reset  
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
0
SF  
Sleep force.  
0 - Do not force invocation of sleep mode.  
1 - Force invocation of sleep mode.  
Note: This bit is cleared on wake-up or a hardware reset.  
31..1  
Reserved.  
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9.5.7.2  
Power Manager General Configuration Register (PCFR)  
The PCFR contains bits used to configure various functions within the SA-1100. The OPDE bit, if  
set, allows the 3.6864-MHz oscillator to be disabled during sleep mode. This bit is cleared on the  
assertion of nRESET. The FP and FS bits control the state of the PCMCIA control pins and the  
static memory control pins during sleep. The following table shows the bit-field definitions for this  
register. The FO bit forces the SA-1100 to assume that the 32-kHz oscillator is stable instead of  
waiting for the requisite 2–10 seconds using an internal counter. This function is primarily useful  
for "warm" hardware resets where the oscillator is already stable when the processor comes out of  
reset.  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
Bit  
R/W  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
4
3
FO  
0
2
FS  
0
1
FP  
0
0
OPD  
E
Reserved  
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
3.6864-MHz oscillator power-down enable.  
0
OPDE  
0 – Do not stop the oscillator during sleep mode (reset condition).  
1 – Stop the 3.6-MHz oscillator during sleep mode.  
1
FP  
Float PCMCIA controls during sleep mode.  
This bit determines whether the PCMCIA control signals are driven to a high (negated)  
state during sleep or not driven (floated). A zero indicates that the pins are driven low. A  
one indicates that they will be floated. This bit is zero at hardware reset. The PCMCIA  
signals affected by this bit are: nPOE, nPWE, nPIOW, nPIOR, nPCE<2:1>, nIOIS16,  
and nPWAIT. PSKSEL and nPREG are derived from address signals and assume the  
state of the address bus during sleep.  
2
3
FS  
FO  
Float static chip selects during sleep mode.  
This bit determines whether the static chip select control signals are driven to a high  
during sleep or floated. A zero indicates that the pins are driven low. A one indicates that  
they will be floated. The static chip select signals affected by this bit are: nCS<3:0>,  
nOE, and nWE. This bit is zero at hardware reset.  
Force 32-kHz oscillator enable on.  
This bit is used to allow software to force the SA-1100 to use the 32-kHz oscillator for  
internal clocking functions instead of waiting for it to stabilize in the normal way. This  
function is  
useful primarily to attain rapid functionality after a "warm" hardware reset when it is  
known that the oscillator is stable. Use of this bit is intended for test purposes and some  
customer use in special situations. It should be used with care, however, since setting  
this bit when the 32-kHz oscillator is not stable will yield unpredictable results.  
31..4  
Reserved.  
9-34  
SA-1100 Developer’s Manual  
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System Control Module  
9.5.7.3  
Power Manager PLL Configuration Register (PPCR)  
The PPCR contains bits used to configure the core operating frequency generated by the PLL. The  
following table shows the bit-field definitions for this register. See Chapter 8, “Clocks” for the  
frequencies generated through settings in this register. Note that the contents of this register are  
preserved during sleep mode and do not need to be re-initialized after a wake-up event. The PPCR  
is only cleared upon the assertion of nRESET (hard reset).  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
Bit  
R/W  
15  
14  
13  
12  
11  
10  
Reserved  
0
9
8
7
6
5
4
3
2
1
0
CCF  
4
CCF  
3
CCF  
2
CCF  
1
CCF  
0
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
4-0  
CCF<4:0>  
Clock speed configuration.  
See Chapter 8, “Clocks” for the values in this field.  
31..5  
Reserved.  
SA-1100 Developer’s Manual  
9-35  
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System Control Module  
9.5.7.4  
Power Manager Wake-Up Enable Register (PWER)  
The following table shows the location of all wake-up interrupt enable bits in the PWER. For a  
GPIO to serve as a wake-up source, it must be programmed as an input in the GPDR. When a fault  
condition is detected in the VDD_FAULT or BATT_FAULT pins, this register is set to hexadecimal  
0000 0003, enabling only GP<1,0> as wake-up sources. This register is also set to this value on  
hard reset (nRESET asserted). For reserved bits, writes are ignored and reads return zero.  
Bit  
31  
30  
0
29  
Reserved  
0
28  
0
27  
26  
25  
WE25  
0
24  
23  
22  
WE22  
0
21  
20  
19  
WE19  
0
18  
17  
16  
WE16  
0
R/W WE31  
WE27 WE26  
WE24 WE23  
WE21 WE20  
WE18 WE17  
Reset  
0
0
0
0
0
0
0
0
0
Bit  
15  
14  
13  
12  
11  
WE11  
0
10  
WE10  
0
9
WE9  
0
8
WE8  
0
7
WE7  
0
6
WE6  
0
5
WE5  
0
4
WE4  
0
3
WE3  
0
2
WE2  
0
1
WE1  
1
0
WE0  
1
R/W WE15 WE14 WE13 WE12  
Reset  
0
0
0
0
Bit  
Name  
Description  
{n}  
WE{n}  
Sleep wake-up enable n (where n = 0 through 27).  
0 – Wake-up due to GPIO<n> edge detect disabled.  
1 – Wake-up due to GPIO<n> edge detect enabled.  
30..28  
31  
Reserved.  
WE31  
Sleep wake-up enable 31.  
0 – Wake-up due to RTC alarm disabled.  
1 – Wake-up due to RTC alarm enabled.  
9-36  
SA-1100 Developer’s Manual  
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System Control Module  
9.5.7.5  
Power Manager Sleep Status Register (PSSR)  
PSSR contains five status flags. The software sleep status flag is set when sleep mode is entered as  
a result of the force sleep (FS) control bit being set by the CPU. The battery fault status bit is set  
any time the BATT_FAULT pin is asserted (even when the SA-1100 is already in sleep mode). The  
VDD fault status bit is set only when the assertion of the VDD_FAULT pin causes sleep mode  
invocation ( that is, if the force sleep bit is asserted and sleep mode is entered followed by the  
assertion of the VDD_FAULT pin, the VDD fault status bit is not set). Hardware (power-on) reset  
clears PSSR, but the sleep mode reset, software reset, and watchdog reset do not affect this register.  
The peripheral hold and DRAM hold bits indicate that those two interfaces retain the same value as  
during sleep until these bits are cleared.  
The five status flags are cleared when a one is written to them. Writing zero to any status bit has no  
effect. Reserved bits read as zeros and are unaffected by writes. The following table shows the  
PSSR.  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
Bit  
R/W  
15  
14  
13  
12  
11  
10  
Reserved  
0
9
8
7
6
5
4
PH  
0
3
DH  
0
2
VFS  
0
1
BFS  
0
0
SWS  
0
Reset  
0
0
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
0
1
2
SS  
Software sleep status.  
0 – Chip has not been placed in sleep mode by setting the force sleep (FS) control bit since it  
was last cleared by reset or by the CPU.  
1– Chip was placed in sleep mode by setting the force sleep (FS) control bit.  
Battery fault status.  
BFS  
VFS  
0 – BATT_FAULT pin has not been asserted since it was last cleared by a hardware reset or  
by the CPU.  
1 – BATT_FAULT pin has been asserted.  
VDD fault status.  
0 – VDD_FAULT pin has not been asserted since it was last cleared by a hardware reset or  
by the CPU.  
1 – VDD_FAULT pin was asserted in run or idle mode and caused the chip to enter sleep  
mode.  
Note: This bit will not be set by the assertion of VDD_FAULT while the SA-1100 is in sleep  
mode.  
SA-1100 Developer’s Manual  
9-37  
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System Control Module  
Bit  
Name  
Description  
3
4
DH  
DRAM control hold.  
This bit is set upon exit from sleep mode and indicates that the RAS<3:0> and CAS<3:0>  
continue to be held low and that the DRAMs are still in self-refresh mode. This bit should be  
cleared by the processor (by writing a one to it) after the DRAM interface has been configured  
but before any DRAM access is attempted. The RAS and CAS lines are released when this  
bit is cleared. This bit is cleared on hardware reset.  
PH  
Peripheral control hold.  
This bit is set upon exit from sleep mode and indicates that the peripheral pins are being held in  
their sleep state. This bit should be cleared by the processor (by writing a one to it) after the  
peripheral interfaces have been configured but before they are actually used by the processor.  
31..5  
Reserved.  
9-38  
SA-1100 Developer’s Manual  
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System Control Module  
9.5.7.6  
Power Manager Scratch Pad Register (PSPR)  
The power manager also contains a 32-bit register to save processor configuration information in  
any format the user desires. The power manager scratch pad register (PSPR) is a holding register  
that is powered by the VDDx power supply pins and is never reset (only configured via writes).  
Any value can be written to it while in run mode. The value remains intact while in sleep mode,  
and can be read once sleep mode is exited. The user may use the register value to represent  
processor configuration prior to sleep mode invocation. (The 32 bits can represent encoded  
configuration information or can act as a pointer to ROM where a configuration table is kept.) The  
PSPR is a simple read/write register. See the Section 9.5.8, “Power Manager Register Locations”  
on page 9-40 for its physical address.  
9.5.7.7  
Power Manager GPIO Sleep State Register (PGSR)  
The GPIO sleep state register (PGSR) allows the user to select the output state of each GPIO pin  
when the SA-1100 goes into sleep mode. When a transition to sleep is required (either through  
software or through the assertion of the BATT_FAULT or VDD_FAULT pins), the contents of the  
PGSR is loaded into the GPIO output data register. [This register is normally controlled by  
software through the GPSR (set) and GPCR (clear) registers]. Only pins already configured as  
outputs will reflect the new state; however, all 28 bits of the output register are loaded. After the  
SA-1100 reenters the run mode from sleep, these GPIO pins retain their programmed sleep state  
until changed by writing ones to the GPSR or GPCR registers; question marks indicate that the  
values are unknown at reset. If a pin direction is switched from an input to an output, the last  
contents of the register will be driven onto the pin.  
Bit  
R/W  
31  
0
30  
29  
0
28  
0
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
SS27 SS26 SS25 SS24 SS23 SS22 SS21 SS20 SS19 SS18 SS17 SS16  
Reset  
0
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
15  
14  
13  
12  
11  
10  
9
SS9  
?
8
SS8  
?
7
SS7  
?
6
SS6  
?
5
SS5  
?
4
SS4  
?
3
SS3  
?
2
SS2  
?
1
SS1  
?
0
SS0  
?
R/W SS15 SS14 SS13 SS12 SS11 SS10  
Reset  
?
?
?
?
?
?
Bit  
Name  
Description  
Sleep state of GPIO n (where n = 0 through 27)  
{n}  
SS{n}  
0 – This pin is driven to a zero during the transition to sleep (if programmed as an  
output).  
1 – This pin is driven to a one during the transition to sleep (if programmed as an  
output).  
31..28  
Reserved  
SA-1100 Developer’s Manual  
9-39  
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System Control Module  
9.5.7.8  
Power Manager Oscillator Status Register (POSR)  
The power manager oscillator status register (POSR) is a single-bit, read-only register that contains  
a status bit indicating whether the 32.768-kHz oscillator is up to speed after a hardware reset. This  
bit is set after the expiration of a timer that is clocked by a ring oscillator. This bit will be set within  
2–10 seconds after the negation of nRESET.  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
Bit  
R/W  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
0
9
8
Reserved  
0
7
6
5
4
3
2
1
0
OOK  
0
Reset  
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
0
OOK  
Oscillator OK.  
This bit is cleared on a hardware reset and set after the 32.768-kHz oscillator has  
stabilized. This bit is read only.  
31..28  
Reserved.  
9.5.8  
Power Manager Register Locations  
Table 9-4 shows the registers associated with the power manager and the physical addresses used  
to access them  
.
Table 9-4.  
Power Manager Register Locations  
Address  
0h 9002 0000  
Name  
PMCR  
Description  
Power manager control register  
0h 9002 0004  
0h 9002 0008  
0h 9002 000C  
0h 9002 0010  
0h 9002 0014  
0h 9002 0018  
0h 9002 001C  
PSSR  
PSPR  
PWER  
PCFR  
PPCR  
PGSR  
POSR  
Power manager sleep status register  
Power manager scratch pad register  
Power manager wake-up enable register  
Power manager general configuration register  
Power manager PLL configuration register  
Power manager GPIO sleep state register  
Power manager oscillator status register  
9-40  
SA-1100 Developer’s Manual  
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System Control Module  
9.6  
Reset Controller  
The reset controller manages the various reset sources within the SA-1100. From a programmer’s  
view, it is visible as two registers: one used to invoke software reset and one to read status after  
booting to indicate why the processor was reset.  
The four types of reset in the SA-1100 include:  
Hardware reset  
Hardware reset is invoked when the nRESET pin is asserted and resets all units in the SA-1100  
to a known state. Hardware reset is intended to be used for power-up only. Because the  
memory controller receives a full reset, all DRAM contents will be lost during hardware reset.  
The RESET_OUT pin is asserted during hardware reset.  
Software reset  
Software reset is invoked when the software reset (SWR) bit in the RSRR is set by software.  
Software reset applies reset to the majority of the SA-1100 as well as causing the assertion of  
the RESET_OUT pin. During software reset, the DRAM refresh and configuration are not  
cleared. This allows DRAM contents to survive a software reset. After the SWR bit is set, the  
SA-1100 stays reset for 256 processor clocks and then is allowed to boot again.  
Watchdog reset  
Watchdog reset is invoked when the watchdog enable bit (WE) in the OWER is set and the  
OSMR3 matches the OS timer counter. When watchdog reset is invoked, the rest of the reset  
sequence is identical to software reset. The watchdog enable bit cannot be cleared under  
program control. Only one of the four reset types can clear it.  
Sleep reset  
Sleep reset is invoked automatically when the SA-1100 enters sleep mode. During sleep mode,  
the majority of the processor loses power and will receive reset prior to the negation of the  
PWR_EN pin. Sleep reset does not affect the power manager, RTC, or GPIO wake-up register.  
During sleep reset, although the memory controller is in reset, the RAS<3:0> and CAS<3:0>  
pins are held in the self-refresh state required by the DRAMs.  
After booting from a reset, software can examine the reset controller reset status register (RCSR)  
to determine which types of reset caused the reset condition.  
SA-1100 Developer’s Manual  
9-41  
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System Control Module  
9.6.1  
Reset Controller Registers  
The reset controller contains two registers, the reset controller software reset register (RSRR) and  
the reset controller reset status register (RCSR).  
9.6.1.1  
Reset Controller Software Reset Register (RSRR)  
The reset controller software reset register has a software reset bit, which when set, causes a reset  
of the SA-1100. The software reset bit (SWR) is located within the least significant bit of the  
write-only reset controller software reset register (RSRR). Writing a one to this bit causes all  
on-chip resources to reset but does not cause the PLL to go out of lock. The software reset bit is  
self-resetting. It is automatically cleared to zero several system clock cycles after a one is written to  
it. Writing zero to the software reset bit has no effect. Care should be taken to restrict access to this  
register by programming MMU permissions. For reserved bits, writes have no effect. Reading this  
register returns zeros.  
The following table shows the RSRR.  
Bit  
Write  
Reset  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
0
Bit  
Write  
Reset  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
0
9
8
Reserved  
0
7
6
5
4
3
2
1
0
SWR  
0
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
0
SWR  
Software reset.  
0 – Do not invoke a software reset of the chip.  
1 – Invoke a software reset of the chip.  
Note: This bit is self-resetting, and is automatically cleared several system clock cycles  
after it has been set.  
31..1  
Reserved.  
9-42  
SA-1100 Developer’s Manual  
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System Control Module  
9.6.1.2  
Reset Controller Status Register (RCSR)  
The reset controller reset status register (RCSR) is used by the CPU to determine the last cause or  
causes of the reset. The SA-1100 has four sources of reset:  
Hardware reset  
Software reset  
Watchdog reset  
Sleep mode reset  
Each RCSR status bit is set by a different source of reset, and can be cleared by writing a one back to that  
bit. Note that the hardware reset state of software, watchdog, and sleep mode reset bits is zero. The table  
below shows the status bits within RCSR. For reserved bits, writes are ignored and reads return zero.  
Bit  
R/W  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
0
16  
0
Reserved  
Reset  
0
8
0
Bit  
R/W  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
9
7
6
5
4
3
SMR  
0
2
1
0
Reserved  
WDR SWR HWR  
Reset  
0
0
0
0
0
0
0
0
1
Bit  
Name  
Description  
0
1
2
3
HWR  
SWR  
WDR  
SMR  
Hardware reset.  
0 – Hardware reset has not occurred since the last time the CPU cleared this bit.  
1 – Hardware reset has occurred since the last time the CPU cleared this bit.  
Software reset.  
0 – Software reset has not occurred since the last time the CPU cleared this bit.  
1 – Software reset has occurred since the last time the CPU cleared this bit.  
Watchdog reset.  
0 – Watchdog reset has not occurred since the last time the CPU cleared this bit.  
1 – Watchdog reset has occurred since the last time the CPU cleared this bit.  
Sleep mode reset.  
0 – Sleep mode reset has not occurred since the last time the CPU cleared this bit.  
1 – Sleep mode reset has occurred since the last time the CPU cleared this bit.  
Note: Each status flag can be cleared only by reading a one and then writing a zero to it.  
31..4  
Reserved.  
9.6.2  
Reset Controller Register Locations  
Table 9-5 shows the registers associated with the reset controller and the physical addresses used to  
access them.  
Table 9-5.  
Reset Controller Register Locations  
Address  
Name  
Description  
0h 9003 0000  
0h 9003 0004  
RSRR  
RCSR  
Reset controller software reset register  
Reset controller status register  
SA-1100 Developer’s Manual  
9-43  
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Memory and PCMCIA Control Module10  
The external memory bus interface for the Intel® StrongARM® SA-1100 Microprocessor  
(SA-1100) supports standard fast-page and EDO asynchronous DRAMs, burst and nonburst  
ROMs, Flash EPROMs, SRAM, and PCMCIA expansion devices. It is programmable through the  
memory interface configuration registers. Figure 10-1 shows a block diagram of the maximum  
configuration of the memory controller.  
Figure 10-1. General Memory Interface Configuration  
RAS3  
DRAM Bank 3  
RAS2  
DRAM Bank 2  
DRAM Bank 1  
DRAM Bank 0  
DRAM Memory Interface  
Up to 4 banks of Standard, EDO,  
or Burst EDO DRAM Memory  
(32-bits wide)  
RAS1  
RAS0  
Intel®  
StrongARM®*  
SA-1100  
Memory  
Controller  
Interface  
CAS<3:0>  
Data Bus  
Buffers  
and  
Transceivers  
Socket 0  
Socket 1  
PCMCIA Interface  
Up to 2-socket support.  
Requires some  
Address Bus  
external buffering  
PCMCIA Control  
CS0  
CS1  
CS2  
CS3  
Static Bank 0  
Static Bank 1  
Static Bank 2  
Static Bank 3  
Static Memory Interface  
Up to 4 banks of ROM, Flash, SRAM memory  
(16-bit or 32-bit wide)**  
** NOTE:  
SRAM width is required to be 32 bits.  
Static bank 0 must be populated by "bootable" memory  
Static RAM support is available in nonRAM systems only.  
* StrongARM is a registered trademark of ARM Limited..  
A6841-01  
10.1  
Overview of Operation  
The SA-1100 memory interface supports three interfaces:  
DRAM Memory Interface  
The dynamic memory interface supports four 32-bit wide banks of fast-page or EDO asynchronous  
DRAMs. Each bank is allocated 128 Mbyte of the internal memory map. However, the actual size  
of each bank is dependent on the particular DRAM configuration used. If multiple banks are  
populated, each must be identical in size and configuration. There are 4 bank selects, nRAS<3:0>,  
SA-1100 Developer’s Manual  
10-1  
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Memory and PCMCIA Control Module  
4 byte selects, nCAS<3:0>, 12 bits of multiplexed row and column addresses, nWE, and nOE. The  
SA-1100 performs CAS before RAS refresh (CBR) during normal operation and supports  
self-refreshing DRAMs during power-down sleep mode.  
Static Memory Interface  
The static memory interface has four chip selects, nCS<3:0>, and 26 bits of byte address, A<25:0>,  
for access of up to 64 Mbyte of memory in each of four banks. Each chip select is individually  
programmable for selecting nonburst ROM, burst ROM, Flash EPROM, or asynchronous SRAM.  
Each may be individually configured to be 16 or 32 bits wide except SRAM, which, if used, must  
be 32 bits. nOE is asserted on reads and nWE is asserted on writes. For SRAMs, nCAS<3:0> are  
byte selects for both reads and writes. Because the nCAS<3:0> pins are used to control both  
SRAM and DRAM, systems with both memory types are not supported.  
When the SA-1100 comes out of reset, it begins fetching and executing instructions at address  
0x00, which corresponds to memory selected by nCS0. This is where boot ROM is expected to be.  
PCMCIA Interface  
The PCMCIA interface provides control signals to support a single PCMCIA card slot with  
additional hooks to support two slots. It shares address and data pins with the memory devices. It  
uses address lines, A<25:0>, and data lines, D<15:0>. nPREG is actually A<26> and selects  
register space (I/O or attribute) versus memory space. nPOE and nPWE are provided for memory  
and attribute reads and writes. nPIOR, nPIOW, and nIOIS16 control I/O reads and writes.  
nPWAIT allows for extended access times. nPCE1 and nPCE2 are byte select low and high,  
respectively. PSKTSEL selects between two card slots.  
This interface also supports 32-bit accesses that are outside the PCMCIA specification. There are  
several restrictions with respect to the use of this feature that are described later in this chapter.  
10-2  
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Memory and PCMCIA Control Module  
10.1.1  
Example Memory System  
Figure 10-2 shows a system using 1M x 16 DRAMs for a total of 16 Mbyte of DRAM. Two banks  
of ROM and two banks of Flash EPROM are shown, each on a 32-bitwide databus. The PCMCIA  
interface is not shown.  
Figure 10-2. Example Memory Configuration  
DRAM  
DRAM  
DRAM  
BANK 2  
DRAM  
BANK 0  
BANK 1  
BANK 3  
nRAS<3:0>  
RAS3  
RAS  
RAS2  
RAS  
RAS1  
RAS0  
RAS  
RAS  
DRAM  
WE  
WE  
WE  
nWE  
WE  
2 Mbyte  
(x16)  
nOE  
OE  
OE  
OE  
OE  
UCAS  
LCAS  
A11-0 D15-0  
UCAS  
LCAS  
A11-0 D15-0  
UCAS  
LCAS  
A11-0 D15-0  
UCAS  
LCAS  
A11-0 D15-0  
D31-16  
D31-0  
CAS3  
CAS2  
CAS1  
CAS0  
RAS  
WE  
RAS  
RAS  
WE  
RAS  
WE  
WE  
OE  
OE  
OE  
OE  
UCAS  
LCAS  
UCAS  
LCAS  
A11-0 D15-0  
UCAS  
LCAS  
UCAS  
LCAS  
A11-0 D15-0  
D15-0  
A11-0  
D15-0  
A11-0  
D15-0  
nCAS<3:0>  
A21/DRA11-  
A10/DRA0  
DRA11-0  
A24-2  
16-bit ROM  
CS3  
A25-22,A9-0  
nCS<3:0>  
CS0  
CS2  
CS1  
CE  
WE  
OE  
A22-0  
D15-0  
16-bit  
ROM  
16-bit  
16-bit  
ROM  
CE  
OE  
CE  
CE  
16-bit  
FLASH  
WE FLASH  
OE  
EPROM  
EPROM  
OE  
A22-0  
D15-0  
A22-0  
A22-0  
D15-0  
D15-0  
D31-16  
CE  
WE  
OE  
A22-0  
D15-0  
16-bit  
16-bit  
ROM  
CE  
OE  
CE  
CE  
16-bit  
ROM  
16-bit  
FLASH  
WE  
OE  
FLASH  
OE  
EPROM  
EPROM  
A22-0  
D15-0  
A22-0  
A22-0  
D15-0  
D15-0  
D15-0  
ROM BANK 0  
ROM BANK 1  
FLASH BANK 1  
FLASH BANK 0  
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Memory and PCMCIA Control Module  
10.1.2  
Types of Memory Accesses  
The SA-1100 performs memory accesses for the following operations:  
Unbuffered write  
Uncached read  
Buffered write  
Linefetch  
Level 1 translation fetch  
Level 2 translation fetch  
Cache line copyback  
Read-lock-write sequence  
Internal DMA read  
Read buffer fetch  
Internal DMA write  
SA-1100 will only generate a subset of all possible transactions on the bus. Many of these  
transactions may be completed internal to the processor by accessing caches, the read buffer,  
on-chip registers, or the memory space that returns zeroes for flushing the cache.  
If a memory access is followed by an idle period on the bus, the control signals will return to their  
inactive state and the address and data signals will remain at their previous values to avoid  
unnecessary bus transitions and eliminating the need for many pull-up resistors.  
10.1.3  
10.1.4  
Reads  
Read bursts are generated by DMA requests, read buffer requests, and cache line fills. All cache  
line fills are 8 words long. DMA and read buffer requests may be 1, 4, or 8 words long. All other  
reads are single accesses.  
Data and instruction cache line fills start on an 8-word boundary and will be 8 words long.  
Writes  
For single access writes, one byte, half-word, or word is written. The write burst sizes are 1, 2, 3, or  
4 full words. A write burst size of 8 words may be generated by castouts and all 32 bytes are  
written.  
For stores to DRAM or SRAM memory spaces, the nCAS<3:0> lines enable a corresponding byte  
of the data bus during a write transaction. Flash memory space stores must be the width of the  
Flash data bus, either 16 or 32 bits.  
10.1.5  
Transaction Summary  
Table 10-1 lists all the transactions that the SA-1100 can generate. No burst will cross an aligned  
32-byte boundary. Note that on a 16-bit bus, the read single operation becomes a two half-word  
burst with address bit 1 always starting at 0. Writes to Flash memory space will take place in one  
single operation regardless of bus size.  
10-4  
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Memory and PCMCIA Control Module  
Table 10-1. SA-1100 Transactions  
Starting  
Address  
Bits <4:2>  
Description  
Burst  
Size  
Bus Operation  
Read single  
Read burst  
1
4
Any  
Generated by core, DMA, or read buffer request.  
Generated by read buffer or DMA request.  
0
4
Read burst  
Write single  
8
1
0
Generated by cacheline fills or read buffer request.  
Any  
1..4 bytes are written as specified by the byte mask.  
Generated by write buffer or DMA request.  
Write burst  
Write burst  
Write burst  
Write burst  
2
3
4
8
0, 1, 2  
4, 5, 6  
All 4 bytes of each word are written. Generated by  
write buffer or DMA request.  
0, 1  
4, 5  
All 4 bytes of each word are written. Generated by  
write buffer or DMA request.  
0
4
All 4 bytes of each word are written. Generated by  
write buffer or DMA request.  
0
Cacheline copyback. All 32 bytes are written.  
Generated by write buffer.  
10.1.6  
10.1.7  
Read-Lock-Write  
The read-lock-write sequence is generated by an SWP instruction to a noncacheable/nonbufferable  
location. Locked access to memory is ensured through internal arbitration of accesses to the  
memory controller.  
Aborts and Nonexistent Memory  
Reads from reserved address locations (as specified in the memory map) will result in a data abort  
exception. Writes to reserved address space will have no effect.  
Reads and writes from or to nonexistent memory are not detected in hardware. In case no memory  
is selected on a read, the value last driven on the data bus is returned.  
A single access to a disabled DRAM bank (MDCNFG:DEx=0) will cause a CBR refresh cycle to  
all banks. Zeros are returned to the register file on reads and writes are dropped. A burst read  
access to a disabled DRAM bank will result in a data abort exception.  
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Memory and PCMCIA Control Module  
10.2  
Memory Configuration Registers  
The SA-1100 memory interface is programmed through a set of configuration registers that are  
described in the following sections.  
Table 10-2 shows the registers associated with the memory interface and the physical addresses  
used to access them. All addressing is little endian. These registers are readable and writable only  
as full words. They are grouped together within one page and thus all have the same memory  
protections.  
Table 10-2. Memory Interface Control Registers  
Physical Address  
0xA000 0000  
Symbol  
MDCNFG  
Register Name  
DRAM configuration register  
0xA000 0004  
0xA000 0008  
0xA000 000C  
0xA000 0010  
0xA000 0014  
0xA000 0018  
MDCAS0  
MDCAS1  
MDCAS2  
MSC0  
DRAM CAS waveform shift register 0  
DRAM CAS waveform shift register 1  
DRAM CAS waveform shift register 2  
Static memory control register 0  
Static memory control register 1  
Expansion bus configuration register  
MSC1  
MECR  
10-6  
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Memory and PCMCIA Control Module  
10.2.1  
DRAM Configuration Register (MDCNFG)  
MDCNFG is a read/write register and contains control bits for configuring the DRAM. All DRAM  
banks must be implemented with the same type of DRAM devices. Question marks indicate that  
the values are unknown at reset.  
Bit  
31  
30  
29  
DRI12  
?
28  
DRI11  
?
27  
DRI10  
?
26  
25  
24  
23  
22  
21  
DRI4  
?
20  
19  
18  
17  
16  
Read DRI14 DRI13  
DRI9 DRI8 DRI7 DRI6 DRI5  
DRI3 DRI2 DRI1 DRI0 TDL1  
Reset  
?
?
?
?
?
9
?
8
?
7
?
6
?
4
?
3
?
2
?
1
?
0
-
Bit  
15  
14  
13  
12  
11  
10  
5
Read TDL0 TRASR3 TRASR2 TRASR1 TRASR0 TRP3 TRP2 TRP1 TRP0 CDB2 DRAC1 DRAC0 DE3 DE2 DE1 DE0  
Reset  
?
?
?
?
?
?
?
?
?
?
?
?
0
0
0
0
Bit  
Name  
Description  
3..0  
DE<3:0>  
DRAM enable bank 3-0.  
For each DRAM bank, there is an enable bit. Reads or writes to a disabled DRAM  
bank trigger a single CBR refresh cycle to all banks. When all banks are disabled,  
the refresh counter is disabled.  
0 – DRAM bank disabled.  
1 – DRAM bank enabled.  
These bits are cleared by hardware reset.  
DRAM row address bit count.  
5..4  
DRAC<1:0>  
00 – 9 row address bits. (Select this for support of 9x9 and 9x8 DRAMs.)  
01 – 10 row address bits. (Select this for support of 10x10, 10x9, and 10x8 DRAMs.)  
10 – 11 row address bits. (Select this for support of 11x11, 11x10, 11x9, and 11x8 DRAMs.)  
11 – 12 row address bits. (Select this for support of 12x10, 12x9, and 12x8 DRAMs.)  
6
CDB2  
Clock divide by 2.  
0 – CAS waveform shift register (MDCAS0, 1, 2) shifted every CPU clock.  
1 – CAS waveform shift register shifted every memory clock. (CPU clock divided by 2.)  
10..7  
TRP<3:0>  
RAS precharge.  
Number of memory clocks nRAS deasserted before next assertion. Between any two  
DRAM accesses, nRAS is high for TRP+1 or 2 memory cycles (whichever is greater).  
Between a DRAM access and a refresh, both nRAS and nCAS are deasserted for  
TRP+1 or 2 memory cycles (whichever is greater).  
14..11 TRASR<3:0> RAS assertion during CBR.  
Number of memory clocks (minus one) nRAS asserted during CAS before RAS  
refresh.  
16..15 TDL<1:0>  
Data input latch after CAS deassertion.  
00 – Read data is latched coincident with the deassertion of nCAS.  
01 – Read data is latched one CPU clock cycle after the deassertion of nCAS (useful for  
EDOs).  
10 – 2 clocks later.  
11 – 3 clocks later.  
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Memory and PCMCIA Control Module  
Bit  
Name  
Description  
31..17 DRI<14:0>  
DRAM refresh interval.  
The number of memory clock cycles (divided by 4) between CAS before RAS (CBR)  
refresh cycles. One row is refreshed in each DRAM bank during each CBR refresh  
cycle.  
The value that must be loaded into this register is calculated as follows:  
DRI = Number of cycles/4 = ((Refresh time / rows) - (longest burst access time)) x  
Mem clock frequency /4.  
The longest burst access time to subtract must also take into consideration access to  
ROM or Flash EPROM. (These may be interrupted to service a DRAM refresh cycle  
after each 32-bit word. If there is a read on a 16-bit bus, a refresh cycle may be  
inserted after 2 read cycles. If there is a read to a 32-bit bus, the refresh waits one  
read cycle to be serviced. The DRAM interface inserts CBR refresh cycles between  
bursts of up to 8 words. Because the address pins are ignored by the DRAMs during  
CBR refresh cycles, PCMCIA transactions may be ongoing during a refresh cycle and  
will not be interrupted.)  
10-8  
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Memory and PCMCIA Control Module  
10.2.2  
DRAM CAS Waveform Shift Registers (MDCAS0, MDCAS1,  
MDCAS2)  
MDCAS0, MDCAS1, and MDCAS2 are 32-bit read/write registers that contain the nCAS  
waveform for a full 8-beat burst read or write to asynchronous DRAM. Each bit represents one  
CPU cycle if MDCNFG:CDB2 is 0 and 2 CPU cycles (1 memory clock cycle) if MDCNFG:CDB2  
is 1. The least significant bit of MDCAS0 goes out first and is the cycle coincident with the  
assertion of nRAS. Bit 1 is one cycle after the assertion of nRAS, and so on. MDCAS1 is  
appended after MDCAS0 and MDCAS2 is appended after MDCAS1. A 1 in any field causes  
nCAS to be deasserted in that cycle; a 0 causes nCAS to be asserted in that cycle. The memory  
controller counts nCAS pulses and deasserts nRAS in the cycle following the deassertion of the  
final nCAS pulse of the burst. All eight nCAS pulses must be programmed or the processor will  
hang. When MDCNFG:CDB2 is 0, the MDCAS0 must contain 1s in the lower 4 bits and each  
transition of nCAS must be a minimum of 2 clocks (nCAS must be asserted for a minimum of  
2 CPU clock cycles and deasserted for 2). When MDCNFG:CDB2 is 1, the MDCAS0 must contain  
1s in the lower 2 bits and each transition of nCAS must be a minimum of 1 bit. These registers are  
unaffected by reset.  
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Memory and PCMCIA Control Module  
10.2.3  
Static Memory Control Registers (MSC1–0)  
MSC1 and MSC0 are read/write registers and contain control bits for configuring static memory  
selected by nCS<3:0>. Reset forces the values in these registers to the slowest possible nonburst  
ROM timing. Timing fields are specified as numbers of memory clock cycles. The memory clock  
cycle consists of two CPU cycles. Each register contains two identical fields, for a total of four  
identical fields, each corresponding to the chip select, nCS<x>, of the same number. On hardware  
reset, the MSC0:SMCNFG0 field is set to 0b 1111 1111 1111 1x00 (binary) where x represents the  
inverse of the ROM_SEL pin. All other fields in MSC0 and MSC1 are unaffected by reset;  
question marks indicate that the values are unknown at reset.  
MSC0 Register Format  
Bit  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Read RRR1_2 RRR1_1 RRR1_0 RDN1_4 RDN1_3 RDN1_2 RDN1_1 RDN1_0 RDF1_4 RDF1_3 RDF1_2 RDF1_1 RDF1_0 RBW1 RT1_1 RT1_0  
Reset  
?
?
?
?
?
?
?
?
9
?
8
?
7
?
6
?
5
?
4
?
3
?
2
?
1
?
0
-
Bit  
15  
14  
13  
12  
11  
10  
Read RRR0_2 RRR0_1 RRR0_0 RDN0_4 RDN0_3 RDN0_2 RDN0_1 RDN0_0 RDF0_4 RDF0_3 RDF0_2 RDF0_1 RDF0_0 RBW0 RT0_1 RT0_0  
Reset  
1
1
1
1
1
1
1
1
1
1
1
1
1
x
0
0
MSC1 Register Format  
Bit  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Read RRR3_2 RRR3_1 RRR3_0 RDN3_4 RDN3_3 RDN3_2 RDN3_1 RDN3_0 RDF3_4 RDF3_3 RDF3_2 RDF3_1 RDF3_0 RBW3 RT3_1 RT3_0  
Reset  
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
-
Bit  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
4
3
2
1
0
Read RRR2_2 RRR2_1 RRR2_0 RDN2_4 RDN2_3 RDN2_2 RDN2_1 RDN2_0 RDF2_4 RDF2_3 RDF2_2 RDF2_1 RDF2_0 RBW2 RT2_1 RT2_0  
Reset  
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
Description  
1..0  
RTx<1:0>  
ROM type.  
00 – Nonburst ROM or Flash EPROM.  
1
01 – Nonburst ROM or SRAM.  
10 – Burst-of-four ROM.  
11 – Burst-of-eight ROM.  
2
RBWx  
ROM bus width.  
0 – 32 bits  
1 – 16 bits  
On reset, the RBW field in SMCNFG0 is loaded with the inverse of the ROM_SEL  
pin.  
7..3  
RDFx<4:0>  
ROM delay first access.  
Number of memory clock cycles (minus 1) from address to data valid for a nonburst  
ROM or the first access of a burst ROM.  
For Flash and SRAM, this determines the read access time.  
One memory clock cycle is added to this value.  
10-10  
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Memory and PCMCIA Control Module  
Bit  
Name  
Description  
12..8  
RDNx<4:0>  
ROM delay next access.  
Number of memory clock cycles (minus 1) from address to data valid for subsequent  
accesses of a burst ROM.  
For Flash and SRAM, this determines the write pulse width.  
One memory clock cycle is added to this value.  
15..13 RRRx<2:0>  
ROM/SRAM recovery time.  
Number of memory clock cycles (divided by 2) from chip select deasserted after a  
read to next chip select (of a different memory bank) or nRAS asserted. nCS  
negated to nRAS asserted is 2*RRR or 1 cycle (whichever is greater).  
For Flash and SRAM, this field will also be used after writes to hold off subsequent  
accesses.  
This field should be programmed with the maximum of Toff, write pulse high time  
(Flash/SRAM), and write recovery before read (Flash).  
1
When SMCNFGx:RT=01, accesses to the selected bank will output a byte mask on nCAS<3:0> for both reads and writes. This  
option should be selected only when there is no DRAM in the system.  
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Memory and PCMCIA Control Module  
10.2.4  
Expansion Memory (PCMCIA) Configuration Register  
(MECR)  
MECR is a read/write register that contains control bits for configuring the timing of the PCMCIA  
interface. This register is unaffected by reset; question marks indicate that the values are unknown  
at reset.  
Writes to the reserved fields have no effect and reads return zeros. The programming of each of the  
six fields allows the user to individually select the duration of accesses to I/O, common memory,  
and attribute memory for each of two PCMCIA card slots. Each field is identical and represents the  
number of memory clocks per tick of an internal clock, referred to as BCLK. BCLK clocks the  
internal PCMCIA state machine. See Figure 10-15 for a description of the PCMCIA timing  
diagram.  
The BCLK_SEL field is designed to allow the user to program the speeds of the PCMCIA memory,  
attribute, and I/O accesses. When an access to a PCMCIA address space is detected, the  
appropriate BS_xx field is selected based on the memory map. Every (BS_xx + 1) memory clock  
cycles, a BCLK tick is generated to advance the PCMCIA state machine. All signals (except  
nPWAIT, which is asynchronous) on the PCMCIA bus are driven or sampled relative to this  
internal clock, although the clock itself is not driven. Table 10-3 shows the number of processor  
clocks per BCLK tick for each BS_xx value. Table 10-4 shows the internal BCLK cycle times for  
each BS_xx setting given a processor core frequency of 160 MHz (6.25-ns cycle time).  
Note: The BCLK speed for a given setting will change if the processor frequency changes.  
Bit  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Read RES BSM2_4 BSM2_3 BSM2_2 BSM2_1 BSN2_0 BSA2_4 BSA2_3 BSA2_2 BSA2_1 BSA2_0 BSIO2_4 BSIO2_3 BSIO2_2 BSIO2_1 BSIO2_0  
Reset  
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
-
Bit  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
4
3
2
1
0
Read RES BSM1_4 BSM1_3 BSM1_2 BSM1_1 BSN1_0 BSA1_4 BSA1_3 BSA1_2 BSA1_1 BSA1_0 BSIO1_4 BSIO1_3 BSIO1_2 BSIO1_1 BSIO1_0  
Reset  
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
Description  
4..0  
9..5  
BSIO1<4:0>  
BSA1<4:0>  
Clock count for accesses to PCMCIA card slot 1, I/O space.  
Clock count for accesses to PCMCIA card slot 1, attribute space.  
14..10 BSM1<4:0>  
15  
Clock count for accesses to PCMCIA card slot 1, common memory space.  
Reserved.  
20..16 BSIO2<4:0>  
25..21 BSA2<4:0>  
30..26 BSM2<4:0>  
Clock count for accesses to PCMCIA card slot 2, I/O space.  
Clock count for accesses to PCMCIA card slot 2, attribute space.  
Clock count for accesses to PCMCIA card slot 2, common memory space.  
Reserved.  
31  
10-12  
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Memory and PCMCIA Control Module  
Table 10-3. BS_xx Bit Encoding  
Bit  
4..0  
Name  
BS_xx  
Description  
0b00000 – BCLK= 2 processor clocks (clk/2)  
0b00001 – BCLK= 4 processor clocks  
0b00010 – BCLK= 6 processor clocks  
....  
0b11101 – BCLK= 60 processor clocks  
0b11110 – BCLK= 62 processor clocks  
0b11111 – BCLK= 64 processor clocks  
Table 10-4. BCLK Speeds for 160-MHz Processor Core Frequency  
BCLK_SEL  
BCLK Cycle Time–ns  
0b00000 – Every 2 processor clocks (clk/2).  
0b00001 – Every 4 processor clocks.  
0b00010 – Every 6 processor clocks.  
0b00011 – Every 8 processor clocks.  
...  
12.5  
25  
37.5  
50  
0b11111 – Every 64 processor clocks.  
400  
To calculate the recommended BS_xx value for each address space: divide the command width  
time (the greater of twIOWR and twIORD, or the greater of twWE and twOE) by processor cycle  
time; divide by 2; divide again by 3 (number of BCLKs per command assertion); round up to the  
next whole number; and subtract 1. For example, for a processor cycle time of 6.25 ns and an  
nIOWR command assertion time of 165 ns, the recommended setting for BS_IO would be  
(165 /(2 x 3 x 6.25)) - 1 = 3.4, or 4 after rounding up.  
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Memory and PCMCIA Control Module  
10.3  
Dynamic Interface Operation  
This section describes the dynamic memory interface.  
10.3.1  
DRAM Overview  
The dynamic memory interface supports up to four banks of identical size and type dynamic  
memory on a 32-bit bus. Initialization software must set up the memory interface configuration  
registers with the DRAM size, type, number of row address bits, nCAS waveforms, and timing  
parameters. The SA-1100 generates accesses of 1–8 words.  
Table 10-5 shows some of the supported DRAM configurations.  
Table 10-5. DRAM Memory Size Options  
DRAM  
Bank Size  
Number  
Chips /  
Bank  
MaxMemory  
(4 Banks,  
32-bit Bus)  
Total  
Number  
of Chips  
Row bits x  
Col. Bits  
Configuration  
Chip Size  
(Mbyte/Bank)  
(Words x Bits)  
1 Mbyte  
2 Mbyte  
2 Mbyte  
4 Mbyte  
4 Mbyte  
8 Mbyte  
16 Mbyte  
256 K x 16  
512 K x 8  
512 K x 32  
1 M x 4  
4 Mbit  
2
9 x 9  
4 Mbyte  
8 Mbyte  
8 Mbyte  
16 Mbyte  
16 Mbyte  
32 Mbyte  
64 Mbyte  
8
4 Mbit  
4
1
8
2
4
2
10 x 9  
16  
4
16Mbit  
4 Mbit  
10 x 9  
10 x 10  
32  
8
1 M x 16  
2 M x 8  
16 Mbit  
16 Mbit  
64 Mbit  
10 x 10, 12 x 8  
11 x 10, 12 x 9  
12 x 10  
16  
8
4 M x 16  
Table 10-6 shows the DRAM row and column address multiplexing. For each row address size specified,  
column address sizes of 11, 10, 9, and 8 are supported wherever the row address is larger than or the same  
size as the column address (12 rows x 11 columns are not supported). Connecting address lines to the  
DRAM chips as shown allows the proper addressing without having to specify the column address size.  
.
Table 10-6. DRAM Row/Column Address Multiplexing  
Number of Row  
Address Bits  
(as specified in  
MDCNFG:DRAC)  
DRAM Address Pins at RAS Time  
DRAM Address Pins at CAS Time  
DRA10 DRA9 DRA8  
IA23 IA22  
DRA11  
DRA10  
DRA9  
DRA8-0  
DRA11  
DRA7-0  
12 bits  
IA21  
IA20  
IA20  
x
IA19  
IA19  
IA19  
x
IA18-10  
IA18-10  
IA18-10  
IA18-10  
x
x
IA9-2  
IA9-2  
IA9-2  
IA9-2  
11 bits  
DRAM:  
x
x
x
x
x
x
IA23  
IA22  
IA21  
x
IA21  
IA20  
IA19  
10 bits  
x
x
9 bits  
x
DRAx = SA-1100 DRAM interface address pin, A(21:10) = DRA(11:0)  
IAx = Internal address bit  
Note: At RAS time, all address pins, A(25:0), are driven with the internal address that corresponds to the pin  
of the same number. For example, a DRAM with 13 bits of row address can be accommodated by  
hooking up the 13th row address line of the DRAM to SA-1100 address pin A22. (MDCNFG:DRAC is  
a "don’t care".) The column address, in this case, will be limited to a maximum of 8 bits. In general,  
DRAMs that utilize fewer than 8 column address bits can be used, but there will be holes in the memory  
map due to no physical memory being addressed by the still significant internal address bit IA9.  
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Memory and PCMCIA Control Module  
10.3.2  
DRAM Timing  
The DRAM nCAS timing is generated using shift registers. The rate at which these shift registers  
are clocked is determined by MDCNFG:CDB2. The time at which to sample the read data is  
programmable to coincide with the deassertion of nCAS or up to 3 CPU cycles later. This method  
provides a way to take advantage of the EDO DRAMs while still supporting the fast-page-mode  
DRAMs. A full 8-beat burst nCAS waveform is specified, and the memory interface controller  
shifts the waveform shift register once every CPU clock cycle if MDCNFG:CDB2=0 and once  
every 2 CPU clock cycles if MDCNFG:CDB2=1. The shifting continues until the number of nCAS  
pulses have been generated that corresponds to the actual number of data words being accessed.  
Registers MDCAS0, MDCAS1, and MDCAS2 contain the nCAS waveform for a full 8-beat burst  
access to DRAM. To begin an access, the row address is output on DRA(11:0), which is A(21:10).  
One CPU clock later (1/2 memory clock), nRAS is asserted and the nCAS waveform begins and is  
shifted with each CPU clock, if MDCNFG:CDB2=0. A 1 in this shift register drives nCAS high  
(deasserts) at the rising edge of the CPU clock cycle, and a 0 drives nCAS low (asserts). The  
column address for the first beat of data will be valid 1 CPU cycle before nCAS transitions from  
deasserted to asserted. During reads, a rising edge is detected on the nCAS waveform and input  
data is latched MDCNFG:TDL cycles after the rising edge. The shift register continues to shift  
until the number of nCAS pulses equals the burst size of the current transaction. For write  
transactions, nRAS will be deasserted on the next rising memory clock edge after the last nCAS  
rising edge (either 1 or 2 CPU clock cycles). For read transactions, nRAS will be deasserted on the  
rising memory clock cycle edge that occurs either 2 or 3 CPU clock cycles after the input data is  
latched. For each additional beat after the first, the column address will be updated coincident with  
the deassertion of nCAS, or 1 CPU cycle later. For writes, the write data outputs will follow the  
same timing as the column address. nWE and nOE, as appropriate, follow the same timing as  
nRAS. After nRAS is deasserted, the timing parameter MDCNFG:TRP is used to determine the  
wait before the next assertion of nRAS.  
If MDCNFG:CDB2=1, the nCAS waveform will be shifted every memory clock, or every 2 CPU  
cycles. The timing of the other signals remains the same relative to the nCAS waveform. For  
MDCNFG:CDB2=0, there is a requirement that nCAS high and low times be programmed with a  
minimum of 2 bits and the 4 least significant bits in MDCAS0 must be 1. For the  
MDCNFG:CDB2=1 case, high and low nCAS pulse times may be 1 bit each and the least significant  
2 bits of MDCAS0 must be 1. These requirements are necessary for the internal hardware to properly  
generate addresses and write data, and for proper address and data setup times.  
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Figure 10-3 shows the rate of the shift registers during DRAM nCAS timing for a single-beat  
transaction.  
Figure 10-3. DRAM Single-Beat Transactions  
CPU Clock  
Memory Clock  
nRAS  
TRP  
nCAS  
ADDR  
ROW  
COL  
ROW  
Reads:  
Latch Input Data  
nOE  
Input Data  
DO  
Writes:  
nWE  
Write Data  
DO  
Contents of DRAM register fields:  
time  
last  
first  
MDCAS1 = 11 0001 1000 11000 (binary) MDCAS0 = 0110 0011 0001 1000 1100 0110 0000 0111 (binary)  
MDCNFG:TRP = 4 MDCNFG:CDB2 = 1 TDL = 00  
A4777-01  
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Memory and PCMCIA Control Module  
Figure 10-4 shows the rate of the shift registers during DRAM nCAS timing for burst-of-eight  
transactions.  
Figure 10-4. DRAM Burst-of-Eight Transactions  
Memory Clock  
TRP  
nRAS  
nCAS  
ADDR  
COL  
COL+4 COL+8 COL+12 COL+16 COL+20 COL+24  
COL+28  
ROW  
Reads:  
nOE  
Input Data  
D0  
D1  
D2  
D3  
D4  
D5  
D6  
D7  
Latch Input Data (internal):  
Writes:  
nWE  
Write Data  
D0  
D1  
D2  
D3  
D4  
D5  
D6  
D7  
Contents of DRAM register fields:  
time  
last  
first  
MDCAS1 = 11 0001 1000 1100 (binary) MDCAS0 = 0110 0011 0001 1000 1100 0110 0000 0111 (binary)  
MDCNFG:TRP = 4 MDCNFG:CDB2 = 1 TDL = 00  
A4778-01  
Contents of DRAM register fields:  
MDCAS1=11 0001 1000 1100(binary)  
MDCNFG:TRP=4  
time  
MDCAS0= 0110 0011 0001 1000 1100 0110 0000 0111(binary)  
last  
TDL=00  
MDCNFG:CDB2=1  
first  
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Memory and PCMCIA Control Module  
10.3.3  
DRAM Refresh  
The SA-1100 provides support for CAS before RAS (CBR) refresh. When the DRAM interface is  
enabled [by setting any of MDCNFG:DE(3-0) and setting MDCNFG:DRI greater than zero], the  
refresh counter starts counting up every memory cycle (2 CPU cycles) from 0. When its value  
reaches the value in MDCNFG:DRI times 4, the memory controller is notified that a refresh cycle  
is due, then the counter is cleared and resumes counting. After the current transaction completes, a  
refresh cycle is performed. All four nCAS lines are asserted. Two memory clock cycles later  
(4 CPU cycles), the nRAS signals for all enabled banks are asserted and held low for  
MDCNFG:TRASR+1 memory clock cycles. After that, all nRAS and nCAS signals are deasserted  
and MDCNFG:TRP is used to hold off subsequent DRAM accesses to allow for row precharge  
time. Hardware reset clears the refresh counter. Software reset does not affect it.  
A read or write to any disabled DRAM bank will cause a refresh cycle to all banks to occur.  
Figure 10-5 shows a timing diagram of a CBR refresh cycle.  
Figure 10-5. DRAM Refresh Cycle  
CPU Clock  
Memory Clock  
nCAS[3:0]  
TRASR+1  
nRAS[3:0]  
A4779-01  
10.3.4  
DRAM Self-Refresh in Sleep Mode  
The SA-1100 will put the DRAM into the self-refresh state prior to entering sleep mode by  
asserting nCAS, then asserting nRAS (just as for a normal CBR refresh cycle), and maintaining  
nCAS and nRAS low while power and clocks are turned off.  
See Section 9.5, “Power Manager” on page 9-26 for details on how to bring the DRAMs out of  
self-refresh mode. An access to a DRAM bank while the DRAM interface is in self-refresh mode  
will have undefined results, but the DRAMs will remain in self-refresh mode.  
10.4  
Static Memory Interface  
The static memory interface is comprised of four chip selects, nCS<3:0>, and are each configurable  
for ROM, burst ROM, SRAM, or Flash EPROM. The data bus for each chip select region may be  
programmed to be 16 or 32 bits wide, although if SRAM is selected, only a 32-bit bus is supported.  
nOE is asserted for all reads. nWE is asserted for Flash and SRAM writes. For SRAM  
implementations, nCAS<3:0> signals are used for the byte enables where nCAS<3> corresponds to  
the MSB. The SA-1100 supplies 26 bits of byte address (A<25:0>) for access of up to 128 Mbyte per  
chip select. A<0> is not used in 16-bitwide bus systems and <1:0> are not used in 32-bitwide  
systems.  
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Memory and PCMCIA Control Module  
The RT fields in the MSCx registers specify the type of memory (burst-of-four ROM, burst-of-eight  
ROM, nonburst ROM, Flash, SRAM) and the RBW fields specify the bus width for the memory space  
selected by nCS<3:0>. If a 16-bit bus width is specified, transactions take place across data pins  
D<15:0>.  
10.4.1  
ROM Interface Overview  
The SA-1100 provides programmable timing for both burst and nonburst ROMs. The RDF field in  
MSCx is the latency (in memory clock cycles) for nonburst ROMs and the first data beat of a burst  
ROM. RDN is the latency for the burst data beats after the first for burst ROMs. RRR delays the  
following access to a different memory space to allow time for the current ROM to tristate the data  
bus. This parameter should be programmed with the maximum tOFF value, as specified by the  
ROM manufacturer. One memory clock cycle is added to each of these parameters. At power-on  
reset, the SMCNFG0 field in the MSC0 register is initialized such that the RDF, RDN, and RRR  
fields are set to their maximum values to accommodate the slowest ROMs at initial boot; RT is set  
to be nonburst ROM; and RBW0 is loaded with the value of the inverse of the ROM_SEL pin. The  
remaining fields in MSC0 and MSC1 are not initialized on power-on reset. MSC0:SMCNFG0 is  
selected when the address space corresponding to nCS0 is accessed.  
The SA-1100 supports a ROM burst size of 1, 4, or 8 words. A single DRAM CBR refresh cycle  
may be inserted between word accesses within a transaction. nCS and nOE are deasserted during  
the refresh cycle.  
10.4.2  
ROM Timing Diagrams and Parameters  
Figure 10-6, Figure 10-7, and Figure 10-8 show the timing for burst and nonburst ROMS.  
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Figure 10-6. Burst-of-Eight ROM Timing Diagram  
Memory Clock  
nCS0  
A[25:5]  
RDN+1 RDN+1 RDN+1 RDN+1 RDN+1 RDN+1 RDN+1  
RDF+1.5  
0
A[4:2]  
nOE  
1
2
3
4
5
6
7
D0  
D1  
D2  
D4  
D5  
Input Data  
Latch  
Input Data  
(2*RRR)+1  
nCS1  
Note: One extra CPU cycle (1/2 memory cycle) is added to the first access after nCS is asserted.  
In this example, MSC0:SCNFG0:RDF = 12 (decimal), RDN = 4, RRR = 2.  
A4780-01  
Note: One extra CPU cycle (1/2 memory cycle) is added to the first access after nCS is as  
In this example, MSC0:SCNFG0:RDF=12(decimal), RDN=4, RRR=2.  
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Figure 10-7. Eight Beat Burst Read from Burst-of-Four ROM  
Memory Clock  
nCS0  
A[25:5]  
A[4]  
RDN+1 RDN+1 RDN+1  
RDF+1.5  
RDN+1 RDN+1 RDN+1  
RDF+1  
0
1
2
3
0
1
2
3
A[3:2]  
nOE  
D0  
D1  
D2  
D3  
D4  
D5  
D6  
Input Data  
Latch  
Input Data  
(2*RRR)+1  
nCS1  
A4781-01  
Figure 10-8. Nonburst ROM, SRAM, or Flash Read Timing Diagram – Four Data Beats  
Memory Clock  
(2*RRR)+1  
RDF+1.5  
nCS0  
nCAS[3:0]  
(SRAM only)  
nOE  
RDF+1  
A1  
RDF+1  
A2  
RDF+1  
A0  
A3  
D3  
A[25:0]  
D0  
D1  
D2  
Read  
(Input) Data  
Latch  
Read Data  
nCS1  
A4782-01  
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Memory and PCMCIA Control Module  
10.4.3  
SRAM Interface Overview  
The SA-1100 provides a 32-bit asynchronous SRAM interface that uses the nCAS pins for byte  
selects on both reads and writes (nCS<3:0> selects the SRAM bank, nOE is asserted on reads, and  
nWE is asserted on writes). Address bits A<25:2> provide addressability of up to 64 Mbyte of  
SRAM per bank. Because the nCAS signals are used to access SRAM, a system with both SRAM  
and DRAM is not supported.  
The timing for a read access is identical to that for a nonburst ROM. (See section 10.4.2 on page  
19.) The RDF fields in the MSCx registers are the latency for a read access. The MSCx:RDN field  
controls the nWE low time during a write cycle. MSCx:RRR is the time from nCS deassertion after  
a read to the start of an access from a different memory bank or after a write to any other memory  
access. MSCx:RBW must be set to be a 32-bit bus and MSCx:RT must select SRAM.  
10.4.4  
SRAM Timing Diagrams and Parameters  
SRAM reads have the same timing as nonburst ROMs as shown in Figure 10-8, except nCAS<3:0>  
are byte selects and are asserted with the same timing as nCS. When nCAS0 is low (asserted),  
D<7:0> will be used to transfer data. When nCAS1 is low, D<15:8> is used, and so on. During  
writes, all 32 data pins are actively driven by the SA-1100; they are not tristated regardless of the  
state of the individual nCAS pins.  
Figure 10-9 shows the timing for SRAM writes.  
Figure 10-9. SRAM Write Timing Diagram (4–Beat Burst)  
CPU Clock  
Memory Clock  
(2*RRR)+1  
tCEH  
tAS  
nCS0  
tAH  
A0  
tDSWH  
A0+4  
A0+8  
A0+12  
A[25:0]  
tASW  
tDH  
tCES  
RDN+1  
RDN+1  
RDN+1  
RDN+1  
tCES  
nWE  
nOE  
D0  
D1  
D2  
D3  
D[31:0]  
nCAS[3:0]  
A4786-01  
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In Figure 10-9, some of the parameters are defined as follows:  
tAS = Address setup to nCS = 1 CPU cycle  
tCES = nCS, nCAS setup to nWE = 2 memory clock cycles (4 CPU cycles)  
tASW = Address setup to nWE low (asserted) = 1/2 memory cycle (1 CPU cycle)  
[For A<25:5>, tASW=5 CPU cycles. For A<4:2>, tASW=1 CPU cycle for subsequent beats in a  
burst]  
tDSWH = Write data setup to nWE high (deasserted) = 1/2 memory cycle + (RDN+1) memory cycles  
tDH = Data hold after nWE high (deasserted) = 1/2 memory cycle (1 CPU cycle)  
tCEH = nCS, nCAS held asserted after nWE deasserted = 1 memory clock cycle (2 CPU cycles)  
tAH = Address hold after nWE deasserted = 1/2 memory cycle (1 CPU cycle)  
nWE high time between burst beats = 1 memory cycle (2 CPU cycles)  
10.4.5  
FLASH EPROM Interface Overview  
The SA-1100 provides an SRAM-like interface for access of Flash EPROM. The RDF fields in the  
MSCx registers are the latency for a read access. The RDN field controls the nWE low time during  
a write cycle. RRR is the time from nCS deassertion after a read to the start of a read from a  
different memory or after a write to another memory access. A single DRAM CBR refresh cycle  
may be inserted between words of a burst read from Flash memory. During the refresh cycle, nCS  
and nOE will be deasserted.  
There are some requirements for writes to Flash memory. Flash memory space must be uncacheable  
and unbuffered. Writes must be exactly the width of the populated Flash devices on the data bus (no  
byte writes to a 32-bit bus or word writes to a 16-bit bus, and so on). Software is responsible for  
partitioning commands and data, and writing them out to Flash in the appropriate sequence.  
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10.4.6  
FLASH EPROM Timing Diagrams and Parameters  
Flash reads have the same timing as nonburst ROMs as shown in the preceding figures.  
Figure 10-10 shows the timing for Flash writes.  
Figure 10-10. Flash Write Timing Diagram (2 Writes)  
Write Command  
Write Data  
Possible Read or Write  
CPU Clock  
Memory Clock  
(2*RRR)+1  
tAS  
(2*RRR)+1  
tAS  
tCEH  
tCEH  
tAS  
nCS0  
tASW  
A0  
tAH  
tAH  
A[25:0]  
tCES  
tDSWH  
RDN+1  
tCES  
RDN+1  
tCES  
nWE  
nOE  
tDH  
D[31:0]  
CMD  
DATA  
A4787-01  
In Figure 10-10, some of the parameters are defined as follows:  
tAS = Address setup to nCS = 1 CPU cycle  
tCES = nCS setup to nWE = 2 memory clock cycles (4 CPU cycles)  
tASW = Address setup to nWE low (asserted) = 2-1/2 memory cycles (5 CPU cycles)  
tDSWH = Write data setup to nWE high (deasserted) = 1/2 memory cycle + (RDN+1) memory cycles  
tDH = Data hold after nWE high = 1+1/2 memory cycle  
tCEH = nCS held asserted after nWE deasserted = 1 memory clock cycle (2 CPU cycles)  
tAH = Address hold after nWE deasserted = 1+1/2 memory cycle (3 CPU cycles)  
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Memory and PCMCIA Control Module  
10.5  
General Memory BUS Timing  
This section explains the boundary cases between DRAM, static, and refresh operations.  
10.5.1  
Static Access Followed by a DRAM Access  
With a static memory access, nWE is deasserted 1 memory clock cycle prior to the deassertion of  
nCS. Then memory control will wait 2*RRR memory clock cycles (or 1, whichever is greater)  
before the assertion of nRAS for a DRAM access.  
The SA-1100 always drives the data bus except while doing a read cycle (or while the alternate  
master mode is active). The delay from nOE asserted to data bus high-Z is approximately 0 ns.  
When nOE is deasserted, the data bus drives the same data that was already on the bus.  
10.5.2  
DRAM Access Followed by a Static Access  
After a DRAM read cycle, the memory controller will wait TRP+1 memory cycles (or 2,  
whichever is greater) before nCS is asserted for a static memory access. nWE will be asserted 2  
memory clock cycles after that for a total of TRP+3 memory clock cycles. For a static memory  
write after a DRAM write cycle, nWE will be asserted 3 memory clock cycles after nRAS is  
deasserted.  
When nOE and nRAS are deasserted at the end of a DRAM ready cycle, the SA-1100 nCS<x> and  
nOE may be asserted for a static memory read, at which time the SA-1100 will stop driving in 0 ns.  
If the subsequent access is a static memory write, new data will be driven out TRP+1.5 memory  
clock cycles after the deassertion of nRAS and nOE. The minimum time between the end of a  
DRAM refresh cycle and nWE asserted is 3 memory clock cycles.  
10.5.3  
DRAM Access Followed by a Refresh Operation  
At the end of a DRAM read/write cycle, nCAS will go high 1/2 to 1 memory clock cycles before  
nRAS goes high. For a subsequent refresh cycle, nCAS will go high TRP+1 memory clock cycles  
after the nRAS goes high. After that, nRAS will go high 2 memory clock cycles. In this case, TRP  
is used to hold off nCAS rather than just nRAS. There is no overlap (pipelining) between  
successive memory accesses.  
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Memory and PCMCIA Control Module  
10.6  
PCMCIA Overview  
The SA-1100 PCMCIA interface provides controls for one PCMCIA card slot with a PSKTSEL  
pin for support of a second slot. This 16-bit host interface supports 8- and 16-bit peripherals and  
handles common memory, I/O, and attribute memory accesses. The interface does not support the  
PCMCIA DMA protocol. The duration of each access is based on an internally generated clock that  
is programmed per address space in the MECR register. Figure 10-11 shows the memory map for  
the PCMCIA space.  
Figure 10-11. PCMCIA Memory Map  
Socket 2 Memory Space  
Socket 2 Attribute Space  
Reserved  
0h3C00 0000  
0h3800 0000  
0h3400 0000  
0h3000 0000  
0h2C00 0000  
0h2800 0000  
0h2400 0000  
0h2000 0000  
Socket 2 I/O Space  
Socket 1 Memory Space  
Socket 1Attribute Space  
Reserved  
Socket 1 I/O Space  
The PCMCIA memory space is divided into eight partitions, four for each card slot. The four  
partitions for each card slot are common memory, I/O, attribute memory, and a reserved space.  
Each partition starts on a 64 Mbyte boundary. Pins A<25:0>, nPREG, and PSKTSEL are driven at  
the same time. nPCE1 and nPCE2 are driven at address time for memory and attribute accesses.  
For I/O accesses, their value depends on the value of nIOIS16 and thus will be valid a finite time  
after nIOIS16 is valid.  
Common memory accesses assert the nPOE or nPWE control signals and are always 16-bit  
accesses with nPCE1 asserted for low byte access and nPCE2 asserted for high byte access. I/O  
accesses assert the nIOR or nIOW control signals and use the nIOIS16 input signal to determine  
the bus width of the transfer (8 or 16 bit). The SA-1100 uses nPCE2 to indicate to the expansion  
device that the upper half of the data bus, D<15:8>, will be used for the transfer and nPCE1 to  
indicate that the lower half of the data bus, D<7:0>, will be used. When nPCE2 is low, A<0> is  
ignored and an odd byte is transferred across D<15:8>. If nPCE2 is high and nPCE1 is low, then  
A<0> is used to determine whether the byte being transferred across D<7:0> is the odd byte or  
even byte. Transfers always start assuming a 16-bit bus. After the address is placed on the bus, an  
I/O device may respond with nIOIS16 indicating that it can perform the transfer in a single 16-bit  
transfer. If nIOIS16 is not asserted within the proper time, the address is assumed to be to two 8-bit  
registers and the transfer is completed as two 8-bit transfers on the low byte lane, D<7:0>, with  
nPCE2 deasserted, nPCE1 asserted, A<0> =0 for the first 8-bit transfer, and A<0> =1 for the  
second 8-bit transfer.  
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Memory and PCMCIA Control Module  
10.6.1  
32-Bit Data Bus Operation  
The SA-1100 PCMCIA interface supports the use of a 32-bit data bus. Because the PCMCIA 2.0 is  
8- or 16-bit only, the 32-bit operation is outside the scope of the PCMCIA specification. This 32-bit  
mode is intended for use as a nonstandard expansion bus for communication with  
customer-designed logic. The operation is fairly simple; if a word read or write is performed to  
PCMCIA memory space, then the entire 32-bit bus is read or written. Normal PCMCIA operations  
should be performed using byte or half-word accesses only. Thirty-two bit accesses should be word  
aligned and only to "16-bit" space, as opposed to 8-bit space. Memory and attribute space is 16 bits  
by definition. However, I/O space may be 8- or 16-bit depending upon the state of the nIOIS16  
input pin. Thirty-two bit accesses to I/O space require that the target assert nIOIS16.  
For 32-bit accesses, the only size information present on the bus is the assertion of the nPCE1 and  
nPCE2 pins. This is the same information that is present during half-word accesses. As such, there  
is no way by looking at the SA-1100 pins to determine whether the access is a half-word or word.  
This information can be derived only though a user-defined address decode outside the SA-1100.  
The following table shows the operation of the PCMCIA interface and its relation to data width.  
Data Bus  
Width  
1 = 16 Bit  
0 = 8 Bit  
Access Type  
Address (1:0)  
Resulting Operation  
Word  
1
00  
Word read or write, nPCE1 and nPCE2 asserted (low).  
nIOIS16 must be asserted for I/O space.  
1x  
Undefined operation.  
Undefined operation.  
Undefined operation.  
x1  
0
1
xx  
Half-word  
x0 (even)  
Single half-word access, nPCE1 and nPCE2 asserted  
(low). nIOIS16 must be asserted for I/O space.  
x1 (odd)  
Undefined operation.  
0
1
0
x0 (even)  
Two-byte accesses, both on the lower byte lane. Even  
access first (nPCE1 asserted and nPCE2 negated for  
both).  
x1 (odd)  
Undefined operation.  
Byte  
x0 (even)  
Load or store byte on the lower byte lane (nPCE1  
asserted, nPCE2 negated).  
x1 (odd)  
Load or store byte on the upper byte lane (nPCE1  
negated, nPCE2 asserted).  
xx (even or odd)  
Load or store byte on the low byte lane (nPCE2  
negated and nPCE1 asserted).  
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Memory and PCMCIA Control Module  
10.6.2  
External Logic for PCMCIA Implementation  
The SA-1100 requires external logic to complete the PCMCIA socket interface. Figure 10-12 and  
Figure 10-13 show general solutions for a one- and two-socket configuration. Figure 10-14 shows  
a solution for the voltage-control circuit. These diagrams provide the logical connections necessary  
for support of 3 V and 5 V PCMCIA cards as well as hot insertion capability. For dual-voltage  
support, level shifting buffers are required for all signals. Hot insertion capability requires that each  
socket be electrically isolated from the other. If one or both of these features is not required, then  
some of the logic shown in these diagrams may be eliminated.  
The pull-ups shown are included for compliance with the PCCARD xxx standard. Low power  
systems should remove power from these pull-ups during sleep to avoid unnecessary power  
consumption. The CD<2:1> signals have been “ORed” before being provided to the SA-1100. This  
signal is then routed into a GPIO pin for interrupt capability. Similarly, RDY/BSY is routed to a  
GPIO. The INPACK# signal is not used. In the data bus transceiver control logic, nCE1 should  
control the enable for the low byte lane and nCE2 should control the enable for the high byte lane.  
10-28  
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Memory and PCMCIA Control Module  
Figure 10-12. PCMCIA External Logic for a Two-Socket Configuration  
®
Intel  
®*  
StrongARM  
SA-1100  
Socket 0  
D<15:0>  
D<15:0>  
DIR OE#  
nCEx  
Socket 1  
D<15:0>  
DIR OE#  
nPOE  
nPIOR  
nCEx  
CD1#  
CD2#  
GPIO<w>  
CD1#  
CD2#  
GPIO<x>  
GPIO<y>  
RDY/BSY#  
GPIO(z)  
RDY/BSY#  
PSKTSEL  
A<25:0>  
nPREG  
A<25:0>  
REG#  
A<25:0>  
REG#  
nPCE<1:2>  
nPOE,  
CE<1:2>#  
OE#  
WE#  
IOR#  
IOW#  
6
6
6
nPWE  
nPIOW,  
nPIOR  
CE<1:2>#  
OE#  
WE#  
IOR#  
IOW#  
WAIT#  
nPWAIT  
WAIT#  
IOIS1616#  
nPIOIS16  
IOIS1616#  
* StrongARM is a registered trademark of ARM Limited.  
A6840-01  
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Memory and PCMCIA Control Module  
Figure 10-13. PCMCIA External Logic for a One-Socket Configuration  
Intel®  
StrongARM®*  
SA-1100  
Socket 0  
D<15:0>  
D<15:0>  
DIR OE#  
nPOE  
nPIOR  
nPCEx  
CD1#  
CD2#  
GPIO<y>  
GPIO<z>  
RDY/BSY#  
PSKTSEL  
NC  
A<25:0>  
nPREG  
A<25:0>  
REG  
nPCE<1:2>  
nPOE,  
CE<1:2>#  
OE#  
WE#  
6
6
nPWE  
IOR#  
IOW#  
nPIOW,  
nPIOR  
WAIT#  
nPWAIT  
IOIS1616#  
nPIOIS16  
* StrongARM is a registered trademark of ARM Limited.  
A6844-01  
10-30  
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Memory and PCMCIA Control Module  
Figure 10-14. PCMCIA Voltage-Control Logic  
Intel®  
StrongARM®*  
SA-1100  
Socket x  
2
D<15:0>  
BVD 1,2  
2
VSS 1,2  
EN#  
nCS<3>  
nOE  
Transparent  
Latch  
VPPEN  
Voltage-Control  
Circuit  
3VEN  
5VEN  
WR  
nWE  
* StrongARM is a registered trademark of ARM Limited.  
A6845-01  
The PCMCIA card voltage may be controlled through a set of discrete registers mapped into a  
static chip select. For example, Figure 10-14 shows mapping to chip select 3.  
10.6.3  
PCMCIA Interface Timing Diagrams and Parameters  
Figure 10-15 shows a 16-bit access to a 16-bit memory or I/O device. The parameter, BS, is  
programmed in the MECR register. When common memory is accessed, the MECR:BSM1 or  
MECR:BSM2 field is used, depending on whether card socket 0 or 1 is addressed.  
MECR:BSIO1(2) is used for I/O accesses and MECR:BSA1(2) is used for access to attribute  
memory. Figure 10-15 and Figure 10-16 show the appropriate setting of BS_xx = 0b00001.  
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Memory and PCMCIA Control Module  
Figure 10-15. PCMCIA Memory or I/O 16-Bit Access  
CPU Clock  
Memory Clock  
BS_xx+1  
BCLK  
BS_xx+1  
A, nPREG,  
PSKTSEL  
nPCE2, nPCE1  
3*(BS_xxL+1)  
BS_xx+2  
3*(BS_xx+1)  
nPWE, nPIOW,  
nPOE, or nPIOR  
nIOIS16  
(for I/O only)  
nPWAIT  
Latch Read  
Data  
Read Data  
[15:0]  
Write Data  
[15:0]  
BS_xx = 1  
A4788-01  
10-32  
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Memory and PCMCIA Control Module  
Figure 10-16. PCMCIA I/O 16-Bit Access to 8-Bit Device  
CPU Clock  
Memory Clock  
BS_xx+1  
BCLK  
A[25:1], nPREG,  
PSKTSEL  
BS_xx+1  
2*(BS_xx+1)  
A[0]  
nPCE2  
nPCE1  
3*(BS_xx+1)  
3*(BS_xx+1)  
BS_xx+2  
nPIOR, nPIOW  
nIOIS16  
nPWAIT  
Latch Read  
Data  
Read Data  
Low Byte  
High Byte  
D[7:0]  
Write Data  
D[7:0]  
Low Byte  
High Byte  
BS_xx = 1  
A4788-01  
Timing parameters are in CPU clock cycle units. All are minimums except as noted:  
Address access time: 6*(BS_xx+1)  
Command (nPOE, nPWE, nPIOR, nPIOW) assertion time: 3*(BS_xx+1)  
Address setup to command assert: 3*(BS_xx+1)  
Address hold after command deassertion: BS_xx+1  
nPWAIT valid after command assertion (max): 2*(BS_xx+1) -1  
Chip enable (nPCE1,2) setup to nPOE, nPWE assert: 3*(BS_xx+1)  
Chip enable (nPCE1,2) setup to nPIOR, nPIOW assert: 3*(BS_xx+1) - (nIOIS 16 delay from address)  
Chip enabled hold from command deassert: BS_xx+1  
See Chapter 13, “AC Parameters” for actual AC timing.  
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Memory and PCMCIA Control Module  
10.7  
Initialization of the Memory Interface  
On power-on reset, the dynamic memory interface is disabled and the static interface for the boot  
ROM, connected to nCS0, is configured for the slowest nonburst ROM/Flash EPROM. The  
ROM_SEL pin determines the bus size of the boot ROM (nCS0).  
Initialization software is responsible for setting up the memory interface configuration registers  
before enabling the DRAM interface by setting MDCNFG:DE3-0.  
Most DRAMs require a wait period followed by a series of refresh cycles before the first memory  
access. The SA-1100 provides a mechanism for software to control these events. When a particular  
DRAM bank (bank n, selected by nRAS) is disabled (MDCNFG:DEn=0), a read from any address  
in that bank will trigger a CBR refresh cycle for all banks.  
10.7.1  
Flow of Events After Reset or Exiting Sleep Mode  
On power-on reset, the memory controller is in the following state:  
nRAS(3:0) = 0xF  
nCAS(3:0) = 0xF  
nCS(3:0) = 0xF  
nOE = 1  
nWE = 1  
nPIOR = 1  
nPIOW = 1  
nPOE = 1  
nPWE = 1  
All DRAM banks disabled (MDCNFG:DE3:0 = 0).  
Static interface set to slowest nonburst ROM/Flash timing.  
(MSC0:SMCNFG0 field is initialized as follows:  
RRR=0xF, RDN=0x1F, RDF=0x1F, RBW = not ROM_SEL, RT=0)  
Upon exiting sleep mode, the memory controller is in a state similar to reset, except the nCAS and  
nRAS pins remain asserted to ensure that the DRAMs remain in a self-refresh state until the  
processor has been configured:  
nRAS(3:0) = 0  
nCAS(3:0) = 0  
nCS(3:0) = 0xF  
nOE = 1  
nWE = 1  
nPIOR = 1  
nPIOW = 1  
nPOE = 1  
nPWE = 1  
All DRAM banks disabled (MDCNFG:DE3:0 = 0).  
Static interface set to slowest nonburst ROM/Flash timing.  
(MSC0:SMCNFG0 field is initialized as follows:  
RRR=0xF, RDN=0x1F, RDF=0x1F, RBW = not ROM_SEL, RT=0)  
10-34  
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Memory and PCMCIA Control Module  
The following flow should be followed when coming out of reset, whether for sleep or power-up:  
Read boot ROM and write to memory configuration registers, but do not enable DRAM banks.  
If necessary, finish any DRAM power-up wait period (usually about 100 µs).  
If coming out of sleep, see Section 9.5, “Power Manager” on page 9-26 on how to release the  
nCAS and nRAS pins from their self-refresh state.  
If coming out of sleep, wait the DRAM-specific post-self-refresh precharge period before  
issuing a new DRAM transaction.  
If power-on reset, perform the number of initialization refreshes required by the specific  
DRAM part by reading disabled banks. A read from any disabled bank will refresh all four  
banks.  
Enable DRAM banks by setting MDCNFG:DE3:0.  
10.8  
Alternate Memory Bus Master Mode  
The SA-1100 supports the existence of an alternate master on the memory bus. The alternate  
master is given control of the memory bus (address, data, RAS, CAS, and static controls) using a  
hardware handshake. This handshake is performed through MBREQ and MBGNT, which are  
invoked through the alternate functions on GPIO<22> and GPIO<21> respectively. When the  
alternate master wants to take control of the memory bus, it asserts MBREQ (GPIO<22>). The  
SA-1100 will then complete any pending or in-progress memory operation and any outstanding  
DRAM refresh cycle and then assert MBGNT (GPIO<21>). When the alternate master asserts  
MBGNT, the SA-1100 will tristate the memory bus pins (A<25:0>, D<31:0>, nCS<3:0>, nOE,  
NWE, nRAS<3:0>, nCAS<3:0> ).  
During the tristate period, both MBREQ and MBGNT remain high and an external device may take  
control of the tristated pins. It is recommended that the external device drive all the pins even if  
some are not actually used. This will prevent floating inputs and the crossover current associated  
with them. Note that during the tristate period, the SA-1100 is unable to perform DRAM refresh  
cycles. The alternate master must assume the responsibility for DRAM integrity during this period.  
It is recommended that the system be designed such that the period of alternate mastership is  
limited to much less than the refresh period, or that the alternate master implement a refresh  
counter making it capable of performing refresh at the proper intervals.  
To give up the bus, the alternate master negates MBREQ. The SA-1100 will then negate MBGNT  
and begin driving the bus. If the refresh counter inside the SA-1100 requested a refresh cycle  
during the alternate master tenure, then that refresh cycle is run first, followed by any other bus  
transactions that stalled during that period. This mode is set up by writing to the following  
registers:  
GPIO pin direction register to program GIO<21> as an output and GPIO<22> as an input.  
GPIO alternate function register to program GPIO<21> and GPIO<22> to their alternate  
function.  
Test unit control register (TUCR) to set bit 10.  
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Peripheral Control Module  
11  
This chapter describes the peripheral control units that are integrated within the Intel®  
StrongARM® SA-1100 Microprocessor (SA-1100) and the DMA controller that services them.  
The peripheral units include one parallel data port to drive an LCD display, one synchronous serial  
port, and four asynchronous serial ports that implement different serial protocol standards. Each  
section includes a description of the unit’s operation and the control, data, and status registers used  
to configure the unit. The DMA controller acts as the gateway to the peripheral units. It provides  
DMA access to these units and control and address decode for programmed I/O accesses between  
the processor and registers inside the units. Note that the LCD controller contains its own high  
bandwidth DMA controller that is connected to the ARM™ system bus and is used to read pixel  
and palette information from the off-chip frame buffer.  
11.1  
Read/Write Interface  
The ARM system bus, shown in Figure 11-1, is a high-performance synchronous bus that connects  
the peripheral control module to the SA-1100 CPU and to the external memory controller. The  
DMA connects the ARM system bus to the ARM peripheral bus. The ARM peripheral bus  
implements a standard asynchronous protocol that is used by all peripherals designed for ARM  
chips. This standard allows a single library of peripherals to be developed for the entire ARM  
family of CPUs, providing a means to quickly spin off new chip implementations that contain  
different peripheral mixes for target applications. Note that the LCD controller interfaces to the  
ARM system bus because its throughput requirement is much higher than that of any other serial  
peripheral. Placing the LCD on the ARM system bus allows faster synchronous transfers to be  
made between the external frame buffer and the LCD controller. Additionally, the LCD controller  
contains its own dual-channel DMA controller to supply frame buffer data to the unit.  
Although the ARM peripheral bus supports 32 bits of data, the register size (width) implemented  
for each peripheral is equal to the maximum data size that must be coherently read or written by the  
CPU and DMA. This minimizes the size of the peripheral while providing the necessary memory  
throughput for the unit. Although the peripherals’ register sizes vary, the ARM peripheral bus does  
not support byte or half-word accesses. Only word accesses are allowed. Table 11-1 shows the  
register width, DMA port size, and DMA burst size of each of the six peripherals (and the PPC)  
implemented on the SA-1100.  
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Peripheral Control Module  
Figure 11-1. Peripheral Control Module Block Diagram  
ARM™* System Bus  
DMA  
Controller  
ARM™ Peripheral Bus  
LCD  
Controller  
Serial Port 0  
UDC  
Serial Port 1  
SDLC/UART  
Serial Port 2  
ICP  
Serial Port 3  
UART  
Serial Port 4  
MCP/SSP  
L_PCLK  
L_BIAS  
UDC+  
UDC-  
TXD1  
RXD1  
TXD2  
RXD2  
TXD3  
RXD3  
TXD4  
SCLK  
* ARM is a trademark of ARM Limited.  
A6833-01  
Table 11-1.  
Peripheral Control Modules’ Register Width and DMA Port Size  
Register Width /  
DMA Port Size  
Peripheral  
DMA Burst Size  
LCD controller  
32  
8
4 words  
8 bytes  
4 bytes  
4 bytes  
4 bytes  
8 bytes  
4 bytes  
8 bytes  
8 bytes  
N/A  
Serial port 0: UDC  
UART  
SDLC  
UART  
HSSP  
8
Serial port 1:  
8
8
Serial port 2: ICP  
Serial port 3: UART  
Serial port 4:  
8
8
MCP  
SSP  
16  
16  
32  
Peripheral pin controller (PPC)  
11.2  
Memory Organization  
Several of the serial ports contain more than one serial engine. Each individual engine is  
self-contained (no shared logic or registers) and implements a separate serial protocol. Serial ports  
1, 2, and 4 each contain two separate serial engines, totalling eight separate serial engines within all  
five serial ports. Each of the eight serial engines, including the peripheral pin controller (PPC), has  
been allocated a separate 64 Kbyte block on-chip memory space in which its registers reside.  
Although the register width of individual units varies, each register is right justified on word  
boundaries. All register accesses via the CPU must be performed using word reads and writes. This  
chapter includes a summary of individual peripheral registers. See Appendix A, “Register  
Summary” for a complete summary of all on-chip registers.  
11-2  
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Peripheral Control Module  
Table 11-2 shows the base address for each of the peripheral control units.  
Table 11-2. Peripheral Units’ Base Addresses  
Peripheral  
Serial Protocol  
Base Address  
LCD Controller  
Serial Port 0  
0h B010 0000  
0h 8000 0000  
0h 8001 0000  
0h 8002 0000  
0h 8003 0000  
0h 8004 0000  
0h 8005 0000  
0h 8006 0000  
0h 8007 0000  
0h 9006 0000  
USB  
UART  
SDLC  
UART  
HSSP  
UART  
MPC  
Serial Port 1  
Serial Port 2  
(ICP)  
Serial Port 3  
Serial Port 4  
SSP  
1
Peripheral Pin Controller (PPC)  
1 The PPC does not support DMA requests.  
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Peripheral Control Module  
11.3  
Interrupts  
Each peripheral unit interfaces to the interrupt controller within the system control module. The  
interrupt controller contains a 32-bit interrupt pending register, which when read, informs the user  
of all the units on the SA-1100 that are currently generating an unmasked interrupt. Once the user  
determines which unit is causing the interrupt, the unit’s status registers can be read to determine  
the exact cause of the interrupt. This mechanism provides a two-level approach to identify the  
source of any interrupt from the hundreds of possible interrupt sources that exist on the SA-1100.  
Each of the peripheral units generate either one or two interrupts that correspond to specific  
interrupt pending bits within the interrupt controller. Serial ports 1 and 4 each contain two  
independent serial engines. Although each peripheral uses only one set of pins for serial  
communication, the user may choose to use both serial engines within serial ports 1 and 4 by  
assigning one of the two protocols to communicate off-chip by taking control of GPIO pins.  
Because the two engines within serial ports 1 and 4 can operate at the same time, these two units  
are assigned two separate interrupt request numbers within the interrupt controller’s pending  
register. Table 11-3 shows the interrupt level for each of the peripheral control units.  
Table 11-3. Peripheral Units’ Interrupt Numbers  
Interrupt  
Number  
Peripheral  
LCD controller  
12  
13  
14  
15  
16  
17  
18  
19  
Serial port 0: USB  
SDLC  
Serial port 1:  
UART  
Serial port 2: ICP  
Serial port 3: UART  
MCP  
Serial port 4:  
SSP  
11-4  
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Peripheral Control Module  
11.4  
Peripheral Pins  
Each peripheral has a number of dedicated pins with which to communicate to off-chip devices.  
The six peripherals of the SA-1100 use a total of 24 pins: the LCD uses twelve pins; serial port 4  
four pins; and serial port 0 through 3 each use two pins. Many applications may not require the use  
of all six of the SA-1100’s peripherals. To provide maximum flexibility, the pins associated with  
any unused peripheral (except serial port 0) can be used as general-purpose digital input/output  
pins that are noninterruptible. When a peripheral is disabled, the peripheral pin controller (PPC)  
automatically takes control of the peripheral’s pin direction and pin state. A user can sample input  
pin state by reading the PPC pin state register (PPSR) and control the state of an output pin by  
writing to it. Pin direction is established by configuring the PPC pin direction register (PPDR).  
Table 11-4 shows a list of the pins associated with the peripheral units.  
.
Table 11-4. Dedicated Peripheral Pins  
Peripheral  
GPIO Pin  
Function  
L_PCLK  
L_LCLK  
L_FCLK  
L_BIAS  
LDD<7:0>  
UDC+  
Pixel clock  
Line clock/horizontal sync pulse  
Frame clock/vertical sync pulse  
A/C bias signal  
LCD Controller  
Pixel data  
Positive differential receiver  
Negative differential receiver  
Serial transmit data  
Serial receive data  
Serial transmit data  
Serial receive data  
Serial transmit data  
Serial receive data  
Serial transmit data  
Serial receive data  
Serial clock  
Serial port 0: USB  
UDC-  
TXD_1  
RXD_1  
TXD_2  
RXD_2  
TXD_3  
RXD_3  
TXD_C  
RXD_C  
SCLK_C  
SFRM_  
Serial port 1: SDLC/UART  
Serial port 2: ICP  
Serial port 3: UART  
Serial port 4: MPC/SSP  
Serial frame clock  
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Peripheral Control Module  
11.5  
Use of the GPIO Pins for Alternate Functions  
Each of the SA-1100’s six peripheral units has a number of dedicated pins that can be used to drive  
an LCD display, communicate serially with off-chip devices, or be used as general-purpose digital  
input/output pins. Each of the peripherals, except serial port 0 and 2, also has programming options  
that allow the unit to take over control of one or more GPIO pins from the system control module  
to be used for various special functions. Several control bits must be programmed to enable GPIO  
use by peripheral units. First, the user must enable the special function either within the peripheral  
unit or within the peripheral pin controller (PPC). Second, the user must enable the GPIO pin to  
communicate to the peripheral and select the pin’s direction by programming the GPIO alternate  
function register (GAFR) and GPIO pin direction register (GPDR), respectively. See Section 9.1,  
“General-Purpose I/O” on page 9-1 for a description of these GPIO registers. Table 11-5 shows the  
GPIO pins that can be used for alternate peripheral pin functions.  
Table 11-5. Peripheral Unit GPIO Pin Assignment  
Peripheral  
GPIO Pin  
Function  
LDD<8> pin for dual-panel color mode.  
GPIO<2>  
GPIO<3>  
GPIO<4>  
GPIO<5>  
GPIO<6>  
GPIO<7>  
GPIO<8>  
GPIO<9>  
LDD<9> pin for dual-panel color mode.  
LDD<10> pin for dual-panel color mode.  
LDD<11> pin for dual-panel color mode.  
LDD<12> pin for dual-panel color mode.  
LDD<13> pin for dual-panel color mode.  
LDD<14> pin for dual-panel color mode.  
LDD<15> pin for dual-panel color mode.  
LCD  
Controller  
Serial port 0:  
USB  
N/A  
None.  
GPIO<14> Transmit pin for UART when SDLC and UART both needed.  
GPIO<15> Receive pin for UART when SDLC and UART both needed.  
GPIO<16> Sample clock input/output to SDLC.  
Serial port 1:  
SDLC/UART  
GPIO<17> Toggle to drive external tristate for SDLC transmit packets.  
GPIO<18> Sample clock input to UART.  
Serial port 2:  
ICP  
N/A  
None.  
Serial port 3:  
UART  
GPIO<20> Sample clock input to UART.  
GPIO<10> Transmit pin for SSP when MCP and SSP both needed.  
GPIO<11> Receive pin for SSP when MCP and SSP both needed.  
GPIO<12> SCLK pin for SSP when MCP and SSP both needed.  
GPIO<13> SFRM pin for SSP when MCP and SSP both needed.  
Serial port 4:  
MPC/SSP  
Clock input pin for SSP to drive the frame and sample rates when other than  
GPIO<19>  
nonmultiple of 3.6864 MHz needed.  
Clock input pin for MCP to drive the frame and sample rates when other than  
12 Mbps needed.  
GPIO<21>  
11-6  
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Peripheral Control Module  
11.6  
DMA Controller  
The DMA controller consists of six independent DMA channels. Each channel can be configured  
to service any of the serial controllers. Two channels are required to service a full-duplex serial  
controller. The DMA controller is intended to relieve the processor of the interrupt overhead in  
servicing these ports with programmed I/O. If desired, any or all peripherals (except the UDC) may  
be serviced with programmed I/O instead of DMA. Each peripheral is capable of requesting  
processor service through its own interrupt lines or through a DMA request.  
The DMA controller consists of a set of configuration and control registers for each channel and a  
common data transfer engine that services the active channel. Channels are serviced in a fixed  
priority sequence if the DMA receives multiple requests. Each channel is serviced in increments of  
that device’s burst size and delivered in the granularity of that device’s port width (byte or  
half-word). The burst size and port width for each device is programmed in the channel registers  
and is based on the device’s FIFO depth and bandwidth needs. When multiple channels are actively  
executing, each channel is serviced with a burst of data after which the DMA controller may  
perform a context switch to another active channel. The DMA controller performs context switches  
based on whether a channel is active, whether its target device is currently requesting service (the  
FIFO is half-empty), and where that channel lies in the priority scheme.  
Data transfers are performed between a device (one of the serial controllers) and memory (ROM,  
RAM, Flash, SRAM, or DRAM). DMA transfers to and from PCMCIA space are not permitted.  
During a write, a burst of data is read from memory as words into a buffer inside the DMA  
controller. That data is then written to the device according to the device’s port width and the state  
of the endian bit (E). During a read, data is read from the device according to the device’s port  
width and then sent to memory as words. The organization of the bytes inside that word is  
determined again by the endian bit (E).  
The control registers for each channel include two starting address registers and two transfer count  
registers. These registers should be programmed by the system at the start of the transfer. The  
registers control two rotating buffers for use during a transfer. These buffers, designated buffer A  
and buffer B, can be chained together so that when a transfer to (or from) one buffer completes, the  
transfer to (or from) the other begins immediately. By interrogating the status information in the  
channel control/status register, the user can safely update the address pointer and transfer count of  
the inactive buffer.  
11.6.1  
DMA Register Definitions  
Each DMA channel is supported by six 32-bit registers as part of the DMA controller hardware.  
These registers are the DMA device address register (DDARn), DMA control/status register  
(DCSRn), DMA buffer A start address (DBSAn), DMA buffer B start address (DBSBn), DMA  
buffer A transfer count (DBTAn), and DMA buffer B transfer count (DBTBn). (The n is a value  
from 0 to 5 and is the channel number.) A register summary including physical addresses is  
provided at the end of this section.  
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Peripheral Control Module  
11.6.1.1  
DMA Device Address Register (DDARn)  
The DDARn is a 32-bit read/write register containing channel information regarding the target  
device. Writes to this register are blocked if the RUN bit in the DCSRn is one. The following figure  
shows the format for this register; question marks indicate that the values are unknown at reset.  
.
Bit  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
DA  
31  
DA  
30  
DA  
29  
DA  
28  
DA  
27  
DA  
26  
DA  
25  
DA  
24  
DA  
23  
DA  
22  
DA  
21  
DA  
20  
DA  
19  
DA  
18  
DA  
17  
DA  
16  
Read  
Reset  
0
0
0
0
?
?
?
?
?
?
?
?
?
?
?
?
-
Bit  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
4
3
2
1
0
DA  
15  
DA  
14  
DA  
13  
DA  
12  
DA  
11  
DA  
10  
DA  
9
DA  
8
DS  
3
DS  
2
DS  
1
DS  
0
DW  
BS  
E
RW  
Read  
Reset  
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
Description  
0
1
2
3
RW  
Device data transfer direction (read/write).  
0 = Transfer is a write (memory to device).  
1 = Transfer is a read (device to memory).  
E
Device endianess.  
0 = Byte ordering is little endian.  
1 = Byte ordering is big endian.  
BS  
Device burst size.  
0 = Four datums per burst.  
1 = Eight datums per burst.  
DW  
Device datum width.  
0 = Datum size is one byte.  
1 = Datum size is one half-word.  
7..4  
DS<3:0>  
Device select.  
This field is programmed to point to the desired device.  
DA<31:8> Device address field.  
This field is a partial address of the data port of the device currently being serviced.  
31..8  
1
1
“Partial” means that certain bits in the address are assumed to be zero. The DA<31:8> field is constructed as follows:  
DA<31:28> = Device port address 31:28.  
Device port address 27:22 is assumed to be zero.  
DA<27:8> = Device port address 21:2.  
Device port address 1:0 is assumed to be zero.  
11-8  
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Peripheral Control Module  
The value written to the device select DS<3:0> field specifies which DMA request this channel  
responds to. The device datum width (DW) field value is fixed for each device type and indicates  
whether the device’s data port is one or two bytes wide. If the datum width is programmed  
incorrectly for a particular device select, then the results are unpredictable.  
The device burst size (BS) field value is fixed for each device type. It indicates how many beats of  
the datum width are transferred each time the device requests service. This value is chosen based  
on the FIFO size of the particular device. If the burst size is programmed incorrectly for a particular  
device select, then the results are unpredictable.  
The device endianess E field value indicates the byte ordering within a word when data is read  
from or written to memory. If the E bit is zero, then memory is assumed to be little endian. If the bit  
is one, then memory is assumed to be big endian. The following figure shows big and little endian  
DMA transfers.  
Figure 11-2. Big and Little Endian DMA Transfers  
Big Endian DMA Transfers  
D<31> D<0>  
Little Endian DMA Transfers  
D<31>  
3
D<0>  
3
2
1
0
2
1
0
from memory  
from memory  
DMA  
Controller  
DMA  
Controller  
0
3
2
1
0
3
0
1
2
3
3
1
2
0
1
0
2
3
1
2
0
3
2
0
1
2
3
2
1
0
3
1
From  
To  
To From  
From  
To  
To From  
Half-word wide  
Device  
Byte-wide  
Device  
Half-word wide  
Device  
Byte-wide  
Device  
A6893-01  
The device transfer direction (RW) field indicates the direction of the transfer. A zero indicates that  
the transfer is a write (with respect to the device) and that the flow of data will be from memory to  
the device. If the RW field is programmed to a one, then the transfer is a read and the flow of data  
will be from the device to memory. The transfer direction is fixed for each device type. If the burst  
size is programmed incorrectly for a particular device select, then the results are unpredictable.  
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Peripheral Control Module  
Table 11-6.  
Valid Settings for the DDARn Register  
DDAR Fields  
DS<3:0> DW  
Device  
Address  
Unit Name  
Function  
DA<31:8>  
BS  
E
RW  
UDC transmit  
UDC receive  
SDLC transmit  
SDLC receive  
UART transmit  
UART receive  
0x 8000 0028  
0x 8000 0028  
0x 8002 0078  
0x 8002 0078  
0x 8001 0014  
0x 8001 0014  
0x 8004 006C  
0x 8004 006C  
0x80000A  
0x80000A  
0x80801E  
0x80801E  
0x804005  
0x804005  
0x801001B  
0x801001B  
0x80C005  
0x80C005  
0x814005  
0x814005  
0x818002  
0000  
0001  
0010  
0011  
0100  
0101  
0110  
0111  
0110  
0111  
1000  
1001  
1010  
0
1
1
0
0
0
0
1
1
0
0
0
0
0
0/1  
0
Serial port 0  
0
0
0
0
0
0
0
0
0
0
0
1
0/1  
0/1  
0/1  
0/1  
0/1  
0/1  
0/1  
0/1  
0/1  
0/1  
0/1  
0/1  
1
0
1
0
1
0
1
0
1
0
1
0
Serial port 1  
Serial port 2 HSSP transmit  
HSSP receive  
UART transmit 0x 8003 0014  
UART receive 0x 8003 0014  
Serial port 3 UART transmit 0x 8005 0014  
UART receive  
0x 8005 0014  
0x 8006 0008  
Serial port 4 MCP transmit  
(audio)  
MCP receive  
(audio)  
0x 8006 0008  
0x 8006 000C  
0x 8006 000C  
0x818002  
0x818003  
0x818003  
1011  
1100  
1101  
1
1
1
0
0
0
0/1  
0/1  
0/1  
1
0
1
MCP transmit  
(telecom)  
MCP receive  
(telecom)  
SSP transmit  
SSP receive  
0x 8007 006C  
0x 8007 006C  
0x81C01B  
0x81C01B  
1110  
1111  
1
1
0
0
0/1  
0/1  
0
1
11-10  
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Peripheral Control Module  
11.6.1.2  
DMA Control/Status Register (DCSRn)  
The DCSRn is a 32-bit read/write register that contains control and status bits for the channel. The  
following figure shows the format for this register; question marks indicate that the values are  
unknown at reset.  
Bit  
Read  
Reset  
-
31  
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
?0  
16  
0
Reserved  
0
-
0
Bit  
15  
14  
13  
12  
11  
10  
9
8
7
BIU  
?
6
5
4
3
2
1
IE  
?
0
RUN  
?
STR  
TB  
DON  
EB  
STR  
TA  
DON  
EA  
ERR  
OR  
Read  
Reset  
Reserved  
?
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
Description  
0
RUN  
Run bit.  
This is a control bit and is set by the user to indicate that the device address register has  
been loaded. No transfer will occur on this channel unless this bit is set. Clearing the RUN  
bit on an active channel acts as a pause to that channel. Operation can then be resumed  
by again setting the RUN bit.  
1
2
3
IE  
Interrupt enable.  
This bit enables interrupts to be passed onto the interrupt controller. An interrupt is the  
“OR” of the DONEA, DONEB, and ERROR bits.  
ERROR Transfer error bit.  
ERROR is a status bit and is set to indicate that a memory error has occurred. It can generate  
an interrupt if the IE bit is set. ERROR is cleared by software through setting the RUN bit.  
DONEA Buffer A done.  
This bit is a status bit and indicates that the transfer into or out of buffer A has completed.  
It is cleared by writing a one to it or by setting the STRTA bit. DONEA can generate an  
interrupt if IE is set.  
4
STRTA  
Buffer A transfer start.  
This bit is a control bit and is written by the user. It causes the buffer A transfer to begin.  
This bit is functional only if the RUN bit is set.  
5
6
DONEB This bit is a status bit and indicates that the transfer into or out of buffer B has completed.  
It is cleared by writing a one to it or by setting the STRTB bit. DONEB can generate an  
interrupt if IE is set.  
STRTB  
Buffer B transfer start.  
This bit is a control bit and is written by the processor. It causes the buffer B transfer to  
begin. This bit is functional only if the RUN bit is set.  
7
BIU  
Buffer in use.  
BIU is a status bit and may be read to indicate which buffer (A or B) is active . This bit is  
toggled by the DMA controller when DONEA or DONEB are set. This bit is cleared by all  
reset sources (hard, sleep, watchdog, or software).  
8..31  
Reserved.  
These bits are reserved and read as zeros. Writes to this field have no effect.  
The RUN bit is the channel enable. It should be written to a one when the channel is ready for a  
transfer. It can also be used to pause the channel in the middle of a transfer; when it is set to a one  
again, the channel will resume from the current pointer value using the current active buffer. If the  
RUN bit is cleared in the middle of a burst, the burst will complete before the channel is paused.  
The DDAR may be written only when RUN is zero.  
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Peripheral Control Module  
The IE bit is the interrupt enable for the channel. An interrupt is generated if the DONEA,  
DONEB, or ERROR bits are set and the IE bit is set. The interrupt is negated when all of these  
status bits are cleared.  
The ERROR bit is set if the DMA controller is incorrectly programmed and points to reserved  
memory space. No error is generated for references to nonexistent external memory. If enabled,  
ERROR generates a channel interrupt.  
The DONEA bit is a status bit set by the DMA controller to indicate that the transfer to or from  
buffer A has completed. If enabled, DONEA causes a channel interrupt.  
The STRTA bit is written by the user to start the channel transfer to or from buffer A. When  
DONEA is set, STRTA is cleared. The immediate action resulting from setting STRTA is  
dependent on the state of the BIU bit.  
The DONEB bit is a status bit set by the DMA controller to indicate that the transfer to or from  
buffer B has completed. If enabled, DONEB will cause a channel interrupt.  
The STRTB bit is written by the user to start the channel transfer to or from buffer B. When  
DONEB is set, STRTB is cleared. The immediate action resulting from setting STRTB is  
dependent on the state of the BIU bit.  
The BIU bit indicates the current buffer-in-use (A or B). If BIU is a zero, buffer A is in use. If BIU  
is a one, buffer B is in use.The setting of DONEA or DONEB toggles the BIU bit. This bit is never  
cleared except on reset (either hardware, software, or sleep). For this reason, the processor must  
interrogate this bit before programming the channel for a new transfer. If both STRTA and STRTB  
are set at the same time, the first buffer serviced depends on the state of BIU.  
11.6.1.3  
DMA Buffer A Start Address Register (DBSAn)  
The DBSAn is a 32-bit read/write register that contains the starting memory address for buffer A.  
This register may be written only when STRTA is zero.  
11.6.1.4  
DMA Buffer A Transfer Count Register (DBTAn)  
The DBTAn is a 32-bit read/write register that contains the current transfer count in bytes for buffer  
A. This register may be written only when the STRTA bit for this channel is a zero. The following  
figure shows the format of this register; question marks indicate that the values are unknown at reset.  
.
Bit  
Read  
Reset  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
?0  
1
16  
0
Reserved  
0
Bit  
Read  
Reset  
15  
14  
Reserved  
?
13  
12  
11  
10  
9
8
7
6
5
4
3
2
0
TCA  
12  
TCA  
11  
TCA  
10  
TCA  
9
TCA  
8
TCA  
7
TCA  
6
TCA  
5
TCA  
4
TCA  
3
TCA  
2
TCA  
1
TCA  
0
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
Description  
Transfer count (buffer A).  
0..12  
13..31  
TCA<12:0>  
This field is a 13-bit value and contains the current transfer count (in bytes) for the transfer  
to or from buffer A. The maximum value programmed via this transfer count is 8 Kbyte.  
Reserved. These bits are reserved and read as zeros. Writes to this field have no effect.  
11-12  
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Peripheral Control Module  
11.6.1.5  
11.6.1.6  
DMA Buffer B Start Address Register (DBSBn)  
The DBSBn is a 32-bit read/write register that contains the starting memory address for buffer B.  
This register may be written only while STRTB in the DCSR is zero.  
DMA Buffer B Transfer Count Register (DBTBn)  
The DBTBn is a 32-bit read/write register that contains the current transfer count in bytes for buffer  
B. This register may be written only when the STRTB bit for this channel is a zero. The following  
figure shows the format of this register; question marks indicate that the values are unknown at reset.  
Bit  
Read  
Reset  
31  
0
30  
0
29  
0
28  
0
27  
0
26  
0
25  
0
24  
23  
0
22  
0
21  
0
20  
0
19  
0
18  
0
17  
?0  
1
16  
0
Reserved  
0
Bit  
Read  
Reset  
15  
14  
Reserved  
?
13  
12  
11  
10  
9
8
7
6
5
4
3
2
0
TCB  
12  
TCB  
11  
TCB  
10  
TCB  
9
TCB  
8
TCB  
7
STC  
B6  
TCB  
5
TCB  
4
TCB  
3
TCB  
2
TCB  
1
TCB  
0
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
Description  
0..12  
TCB<12:0> Transfer count (buffer B).  
This field is a 13-bit value and contains the current transfer count (in bytes) for the transfer  
to or from buffer B. The maximum value programmed via this transfer count is 8 Kbyte.  
13..31  
Reserved.  
These bits are reserved and read as zeros. Writes to this field have no effect.  
11.6.2  
DMA Operation  
The DMA controller provides dynamic context switching between active channels on a demand  
basis. A context switch may occur when a channel completes a command or when a particular burst  
(portion of a transfer) has been completed. For example, if the FIFO in a particular transmit serial  
controller is full and cannot accept more data, that channel may be switched out of the active  
context in favor of another channel that is requesting service. An active channel may actually go  
idle many times as the device is serviced. Channels are serviced in a fixed priority with channel 0  
being the highest and channel 5 being the lowest.  
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Peripheral Control Module  
11.6.3  
DMA Register List  
The following table lists the registers contained within the DMA controller:  
Physical Address  
Register Name  
Symbol  
Channel 0 Registers  
0h B000 0000  
DMA device address register.  
DDAR0  
DMA control/status register 0.  
Write ones to set.  
0h B000 0004  
DCSR0  
0h B000 0008  
0h B000 000C  
0h B000 0010  
0h B000 0014  
0h B000 0018  
0h B000 001C  
Channel 1 Registers  
0h B000 0020  
Write ones to clear.  
Read only.  
DMA buffer A start address 0.  
DMA buffer A transfer count 0.  
DMA buffer B start address 0.  
DMA buffer B transfer count 0.  
DBSA0  
DBTA0  
DBSB0  
DBTB0  
DMA device address register 1.  
DDAR1  
DCSR1  
DMA control/status register 1.  
Write ones to set.  
0h B000 0024  
0h B000 0028  
0h B000 002C  
0h B000 0030  
0h B000 0034  
0h B000 0038  
0h B000 003C  
Channel 2 Registers  
0h B000 0040  
Write ones to clear.  
Read only.  
DMA buffer A start address 1.  
DMA buffer A transfer count 1.  
DMA buffer B start address 1.  
DMA buffer B transfer count 1.  
DBSA1  
DBTA1  
DBSB1  
DBTB1  
DMA device address register 2  
DDAR2  
DCSR2  
DMA control/status register 2.  
Write ones to set.  
0h B000 0044  
0h B000 0048  
0h B000 004C  
0h B000 0050  
0h B000 0054  
0h B000 0058  
0h B000 005C  
Channel 3 Registers  
0h B000 0060  
Write ones to clear.  
Read only.  
DMA buffer A start address 2.  
DMA buffer A transfer count 2.  
DMA buffer B start address 2.  
DMA buffer B transfer count 2.  
DBSA2  
DBTA2  
DBSB2  
DBTB2  
DMA device address register 3.  
DDAR3  
DCSR3  
DMA control/status register 3.  
Write ones to set.  
0h B000 0064  
0h B000 0068  
0h B000 006C  
Write ones to clear.  
Read only.  
11-14  
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Peripheral Control Module  
Physical Address  
Register Name  
DMA buffer A start address 3.  
Symbol  
0h B000 0070  
0h B000 0074  
0h B000 0078  
0h B000 007C  
Channel 4 Registers  
0h B000 0080  
DBSA3  
DBTA3  
DBSB3  
DBTB3  
DMA buffer A transfer count 3.  
DMA buffer B start address 3.  
DMA buffer B transfer count 3.  
DMA device address register 4.  
DDAR4  
DCSR4  
DMA control/status register 4.  
Write ones to set.  
0h B000 0084  
0h B000 0088  
0h B000 008C  
0h B000 0090  
0h B000 0094  
0h B000 0098  
0h B000 009C  
Channel 5 Registers  
0h B000 00A0  
Write ones to clear.  
Read only.  
DMA buffer A start address 4.  
DMA buffer A transfer count 4.  
DMA buffer B start address 4.  
DMA buffer B transfer count 4.  
DBSA4  
DBTA4  
DBSB4  
DBTB4  
DMA device address register 5.  
DDAR5  
DCSR5  
DMA control/status register 5.  
Write ones to set.  
0h B000 00A4  
0h B000 00A8  
0h B000 00AC  
0h B000 00B0  
0h B000 00B4  
0h B000 00B8  
0h B000 00BC  
Write ones to clear.  
Read only.  
DMA buffer A start address 5.  
DMA buffer A transfer count 5.  
DMA buffer B start address 5.  
DMA buffer B transfer count 5.  
DBSA5  
DBTA5  
DBSB5  
DBTB5  
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Peripheral Control Module  
11.7  
LCD Controller  
The SA-1100’s LCD controller has three types of displays:  
Passive Color Mode  
Supports a total of 3375 possible colors, allowing any 256 colors to be  
displayed each frame.  
Active Color Mode  
Supports up to 65536 colors (16-bit).  
Passive Monochrome ModeSupports 15 gray-scale levels.  
Display sizes up to 1024 x 1024 pixels are supported. However, the size of encoded pixel data within  
the frame buffer limits the maximum size screen the LCD can drive due to memory bus bandwidth.  
The LCD controller also supports single- or dual-panel displays. Encoded pixel data is stored in  
external memory in a frame buffer in 4-, 8-, 12-, or 16-bit increments and is loaded into a 5-entry  
FIFO (32 bits per entry) on a demand basis using the LCD’s own dedicated dual-channel DMA  
controller. One channel is used for single-panel displays and two are used for dual-panel displays.  
Frame buffer data contains encoded pixel values that are used by the LCD controller as pointers to  
index into a 256-entry x 12-bit wide palette. Monochrome palette entries are 4 bits wide; color  
palette entries are 12 bits wide. Encoded pixel data from the frame buffer, which is 4 bits wide,  
addresses the top 16 locations of the palette; 8-bit pixel data accesses any of the 256 entries within  
the palette. When passive color 12-bit pixel mode is enabled, the color pixel values bypass the  
palette and are fed directly to the LCD’s dither logic. When active color 16-bit pixel mode is  
enabled, the pixel value not only bypasses the palette, but also bypasses the dither logic and is sent  
directly to the LCD’s data pins.  
Once the 4- or 8-bit encoded pixel value is used to select a palette entry, the value programmed  
within the entry is transferred to the dither logic, which uses a patented space- and time-based  
dithering algorithm to produce the pixel data that is output to the screen. Dithering causes  
individual pixels to be turned off on each frame at varying rates to produce the 15 levels of gray for  
monochrome screens and 15 levels each for the red, green, and blue pixel components for color  
screens, providing a total of 3375 colors (256 colors are available on each frame). The data output  
from the dither logic is placed in a 19-entry pin data FIFO before it is placed out on the LCD’s pins  
and driven to the display using pixel clock.  
Depending on the type of panel used, the LCD controller is programmed to use either 4-, 8-, or  
16-pixel data output pins. Single-panel monochrome displays use either four or eight data pins to  
output 4 or 8 pixels for each pixel clock; single-panel color displays use eight pins to output 2-2/3  
pixels each pixel clock (8 pins / 3 colors/pixel = 2-2/3 pixels per clock). The LCD controller also  
supports dual-panel mode, which causes the LCD controller’s data lines to be split into two groups,  
one to drive the top half and one to drive the bottom half of the screen. For dual-panel displays, the  
number of pixel data output pins is doubled, allowing twice as many pixels to be output each pixel  
clock to the two halves of the screen.  
In active color display mode, the LCD controller can drive TFT displays. The LCD’s line clock pin  
functions as a horizontal sync (HSYNC) signal, the frame clock pin functions as a vertical sync  
(VSYNC) signal, and the ac bias pin functions as an output enable (OE) signal. In TFT mode, the LCD’s  
dither logic is bypassed, sending selected palette entries (12 bits each) directly to the LCD’s data output  
pins. Additionally, 16-bit pixels can be used that bypass both the palette and the dither logic.  
The LCD controller can be configured in active color display mode and used with an external DAC  
(and optionally an external palette) to drive a video monitor. Note that only monitors that implement  
the RGB data format can be used; the LCD controller does not support the NTSC standard.  
11-16  
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Peripheral Control Module  
When the LCD controller is disabled, control of its pins is given to the peripheral pin controller  
(PPC) to be used as general-purpose digital input/output pins that are noninterruptible. The LCD  
controller’s pins include:  
LDD<7:0>  
Data lines used to transmit either four or eight data values at a time to the LCD display. For  
monochrome displays, each pin value represents a pixel; for passive color, groupings of three  
pin values represent one pixel (red, green, and blue data values). In single-panel monochrome  
mode, LDD<3:0> pins are used. For double-pixel data, single-panel monochrome, dual-panel  
monochrome, single-panel color, and active color modes LDD<7:0> are used.  
GPIO<9:2>  
When dual-panel color or 16-bit TFT operation is programmed, GPIO pins are used as the  
additional, required LCD data lines to output pixel data to the screen.  
L_PCLK  
Pixel clock used by the LCD display to clock the pixel data into the line shift register. In  
passive mode, pixel clock transitions only when valid data is available on the data pins. In  
active mode, pixel clock transitions continuously and the ac bias pin is used as an output to  
signal when data is available on the LCD’s data pins.  
L_LCLK  
Line clock used by the LCD display to signal the end of a line of pixels that transfers the line  
data from the shift register to the screen and increment the line pointers. Also, it is used by  
TFT displays as the horizontal synchronization signal.  
L_FCLK  
Frame clock used by the LCD displays to signal the start of a new frame of pixels that resets  
the line pointers to the top of the screen. Also, it is used by TFT displays as the vertical  
synchronization signal.  
L_BIAS  
AC bias used to signal the LCD display to switch the polarity of the power supplies to the row  
and column axis of the screen to counteract DC offset. In TFT mode, it is used as the output  
enable to signal when data should be latched from the data pins using the pixel clock.  
The pixel clock frequency is derived from the output of the on-chip PLL that is used to clock the  
CPU (CCLK) and is programmable from CCLK/6 to CCLK/514. Each time new data is supplied to  
the LCD data pins, the pixel clock is toggled to latch the data into the LCD display’s serial shifter.  
The line clock toggles after all pixels in a line have been transmitted to the LCD driver and a  
programmable number of pixel clock wait states have elapsed both at the beginning and end of  
each line. In passive mode, the frame clock is asserted during the first line of the screen. In active  
mode, the frame clock is asserted at the beginning of each frame after a programmable number of  
line clock wait states occur. In passive display mode, the pixel clock does not transition when the  
line clock is asserted. However, in active display mode, the pixel clock transitions continuously  
and the ac bias bin is used as an output enable to signal when valid pixels are present on the LCD’s  
data lines. In passive mode, the ac bias pin can be configured to transition each time a  
programmable number of line clocks have elapsed to signal the display to reverse the polarity of its  
voltage to counteract DC offset in the screen.  
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Peripheral Control Module  
11.7.1  
LCD Controller Operation  
The LCD controller supports a variety of user-programmable options including display type and size,  
frame buffer, encoded pixel size, and output data width. Although all programmable combinations are  
possible, the selection of displays available within the market dictate which combinations of these  
programmable options are practical. The type of external memory system implemented by the user  
limits the bandwidth of the LCD’s DMA controller, which, in turn, limits the size and type of screen that  
can be controlled. The user must also determine the maximum bandwidth of the SA-1100’s external bus  
that the LCD is allowed to use without negatively affecting all other functions that the SA-1100 must  
perform. Note that the LCD’s DMA engine has the highest priority on the SA-1100’s internal data bus  
structure (ARM system bus) and can “starve” other masters on the bus, including the CPU.  
The following sections describe individual functional blocks within the LCD controller, frame buffer and  
palette memory organization, and the LCD’s DMA controller. The sections are arranged in order of data  
flow, starting with the off-chip frame buffer and ending with the pins that interface to the LCD display.  
11.7.1.1  
DMA to Memory Interface  
Palette RAM and encoded pixel data are stored in off-chip memory (usually DRAM) in the frame buffer  
and are transferred to the LCD controller’s 5-entry x 32-bit wide input FIFO, on a demand basis, using  
the LCD controller’s dedicated DMA controller. The LCD controller is on the ARM system bus (ASB)  
rather than the ARM peripheral bus (APB), where all other peripherals are located, because it is a higher  
speed synchronous bus that is able to maintain the data rate required for demanding displays, such as  
dual-panel color. The LCD’s DMA contains two channels that transfer data from external memory to the  
input FIFO. One channel is used for single-panel displays and two are used for dual-panel displays.  
The LCD controller issues a service request to the DMA after it has been initialized and enabled.  
The DMA automatically performs four word transfers, filling all but one entry of the FIFO. Values  
are fetched from the bottom of the FIFO, one entry at a time, and each 32-bit value is unpacked into  
individual pixel encodings, of 4, 8, 12, or 16 bits each. After the value is removed from the bottom  
of the FIFO, the entry is invalidated and all data in the FIFO is transferred down one entry. When  
four of the five entries are empty, a service request is issued to the DMA. If the DMA is not able to  
keep the FIFO filled with enough pixel data due to insufficient external memory access speed and  
the FIFO is emptied, the FIFO underrun status bit is set and an interrupt request is made.  
11.7.1.2  
Frame Buffer  
The frame buffer is in an off-chip memory area used to supply enough encoded pixel values to fill the  
entire screen one or more times. At the start or lowest order address of the LCD controller’s frame buffer  
is either a 32- or 512-byte buffer used to store the lookup palette data for each frame. A 32-byte buffer is  
used to load the top 16 entries of the palette for 4-, 12-, or 16-bit pixel encodings, and a 512-byte buffer  
is used to load the entire 256-entry palette for 8-bit pixel encodings. Note that the LCD’s on-chip palette  
is not used for 12- and 16-bit pixel encodings; the PBS field must be programmed to select 12- and  
16-bit pixel mode and the remainder of the 32 bytes at the top of the frame buffer must be zero-filled  
even though the data is not used.  
Each time a new frame is fetched from the frame buffer, the LCD controller’s palette is first loaded with  
the data contained within the palette buffer. Each of the 16 or 256 palette entries is stored in adjacent  
half-words. Figure 11-3 shows the palette-entry organization for little and big endian memory  
organization. The user can select how the LCD views the ordering of frame buffer palette/pixel entries  
by programming the big/little endian select (BLE) bit in LCD control register 0. In little endian mode,  
palette entries are ordered starting with the least significant half-word, followed by the most significant.  
In big endian mode, palette entries are ordered starting with the most significant half-word, followed by  
the least significant. Note that the ordering of the 4-bit R, G, B, and monochrome pixel data (and the  
PBS field) does not change between big and little endian modes; only the relative positioning of the  
individual 16-bit palette entries changes.  
11-18  
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Peripheral Control Module  
Figure 11-3. Palette Buffer Format  
.
Individual Palette Entry  
Bit 15  
Color  
Bit 15  
Mono  
14  
14  
13  
12  
12  
11  
11  
10  
Red (R)  
10  
9
8
7
6
5
4
4
3
3
2
1
0
0
Unused  
PBS*  
Green (G)  
Blue (B)  
13  
9
8
7
6
5
2
1
Unused  
PBS*  
Unused  
Monochrome (M)  
*Note: Pixel bit size (PBS) is contained only within the first palette entry (palette entry 0).  
16- or 256-Entry Palette Buffer  
Bit  
31  
16  
15  
0
Base + 0x0  
Base + 0x4  
Palette entry 1  
Palette entry 3  
Palette entry 0  
Palette entry 2  
.
.
Base + 0x1C  
Base + 0x20  
Palette entry 15  
Palette entry 17  
Palette entry 14  
Palette entry 16  
.
Note: Entries 16 through 254 do not  
.
.
exist for 4-, 12- and 16-bit/pixel modes.  
Base +  
0x1FC  
Palette entry 255  
Palette entry 254  
Base +  
0x200  
Start of Encoded Pixel Data  
Little Endian Palette Entry Ordering  
16 15  
Bit  
31  
0
Base + 0x0  
Base + 0x4  
Palette Entry 0  
Palette Entry 2  
Palette Entry 1  
Palette Entry 3  
.
.
Big Endian Palette Entry Ordering  
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Peripheral Control Module  
The first palette entry (palette entry 0) also contains an extra field that is used to synchronously  
configure the LCD controller at the beginning of each frame. Bits 12 and 13 of the first palette  
entry contain a field that is used to select the number of bits per pixel that is to be used in the next  
frame (see Figure 11-3). The pixel bit size (PBS) bit-field is decoded by the LCD to correctly  
unpack pixel data into nibbles, bytes, 12-bit values, or half-words, and by the palette to tell it how  
many address bits are contained in the pixel data it is supplied, configuring the palette size to 16 or  
256 entries. Note that 12/16-bit pixel mode bypasses the LCD palette and supplies 12-bit values  
directly to the dither logic when passive mode is enabled, or 16-bit values directly to the output  
FIFOs when active mode is enabled. The following table shows the encoding of the PBS bit field.  
Bit  
Name  
PBS  
Description  
13..12  
Pixel bit size.  
0x – 4 bits per pixel, 16-entry palette, 32 bytes of palette buffer transferred each frame  
to palette.  
01 – 8 bits per pixel, 256-entry palette, 512 bytes of palette buffer transferred each  
frame to palette.  
10 – 12 bits per pixel in passive mode (PAS=0), 16 bits per pixel in active mode  
(PAS=1). Palette unused, however, 32 bytes of “dummy” palette data is transferred  
each frame to palette. Palette data must be zero-filled.  
11 – Reserved.  
Note: Two 4-bit pixels are packed into each byte, and 12-bit pixels are right justified on  
half-word boundaries.  
Following the palette buffer is the pixel data buffer that contains one encoded pixel value for each  
of the pixels present on the display. The number of pixel data values depends on the size of the  
screen (1024 x 768 = 786,432 encoded pixel values). Figure 11-4 through Figure 11-7 show the  
memory organization within the frame buffer for each size pixel encoding. Note that for 4-bit  
encodings, 2 pixels are placed into each byte, and for 12-bit encodings the value is right- justified  
within a half-word. These figures show the encoded pixel organization for little endian memory  
organization. The user can select how the LCD views the ordering of frame buffer pixel entries by  
programming the big/little endian select (BLE) bit in LCD control register 0. In big endian mode,  
pixel entries are ordered starting with the most significant nibble, byte, or half-word and ending  
with the least significant.  
Figure 11-4. 4 Bits Per Pixel Data Memory Organization (Little Endian)  
Bit  
3
2
1
0
4 bits/pixel  
Encoded Pixel Data<3:0>  
Bit  
31  
28  
27  
24  
23  
20  
19  
16  
15  
12  
11  
Pixel 2  
8
7
4
3
0
Base +  
0x20  
Pixel 7  
Pixel 6  
Pixel 5  
Pixel 4  
Pixel 3  
Pixel 1  
Pixel 9  
Pixel 0  
Pixel 8  
Base +  
0x24  
Pixel 15  
Pixel 14  
Pixel 13  
Pixel 12  
Pixel 11  
Pixel 10  
..  
11-20  
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Peripheral Control Module  
Figure 11-5. 8-Bits Per Pixel Data Memory Organization (Little Endian)  
Bit  
7
6
5
4
3
2
1
0
8 bits/pixel  
Encoded Pixel Data<7:0>  
Bit 31  
24  
23  
16  
15  
8
7
0
Base +  
0x200  
Pixel 3  
Pixel 7  
Pixel 2  
Pixel 6  
Pixel 1  
Pixel 5  
Pixel 0  
Pixel 4  
Base +  
0x204  
..  
Figure 11-6. 12-Bits Per Pixel Data Memory Organization (Passive Mode Only)  
Bit 15 14 13 12  
12 bits/pixel Unused  
11 10  
9
8
7
6
5
4
3
2
1
0
Red Data<3:0>  
Green Data<3:0>  
Blue Data<3:0>  
Bit  
31  
16  
15  
0
Base + 0x20  
Base + 0x24  
Pixel 1  
Pixel 3  
Pixel 0  
Pixel 2  
..  
Figure 11-7. 16-Bits Per Pixel Data Memory Organization (Active Mode Only)  
)
15 14 13 12  
11 10  
9
8
7
6
5
4
3
2
1
0
Bit  
Encoded Pixel Data<15:0>  
16 bits/pixel  
Bit  
Base + 0x20  
Base + 0x24  
31  
16  
15  
0
Pixel 1  
Pixel 3  
Pixel 0  
Pixel 2  
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Peripheral Control Module  
In dual-panel mode, pixels are presented to two halves of the screen at the same time (upper and lower).  
A second DMA channel and input FIFO exist to support dual-panel operation. The DMA channels  
alternate service requests when filling the two input FIFOs. The palette buffer is implemented in DMA  
channel 1, but not channel 2; the base address points to the top of the encoded pixel values for channel 2.  
The DMA controller contains a base and current address pointer register. The end address is calculated  
automatically by the LCD using the display information such as pixels per line, lines per frame, single-  
or dual-panel mode, color or monochrome mode, and bits per pixel, which are programmed by the user.  
The base address of both DMA channels must be configured such that the least significant four  
address bits are all zero (for example, address bits 3 through 0 must be zero). This requirement  
limits the base address of the frame buffer to start at even 4-word (or 16-byte) intervals.  
The frame buffer must contain an even multiple of 16 pixels for every line and must be aligned on  
a quadword boundary. Many LCD displays are a multiple of 16 pixels wide; however, most  
passive LCD displays are not and will ignore extra pixels at the end of each line. Thus for these  
types of displays that do not use an even multiple of 16 encoded pixel values, the user must adjust  
the start address for each line by adding between 1 and 15 “dummy” pixel values to the end of the  
previous line. For example, if the screen that is being driven is 107 pixels wide, and 4-bits/pixel  
mode is used, each line is 107 pixels or nibbles in length (53.5 bytes). The next nearest 16-pixel  
boundary occurs at 112 pixels or nibbles (56 bytes). Thus, the user must start each new line in the  
frame buffer at multiples of 56 bytes by adding an extra 5 “dummy” pixels per line (2.5 bytes). The  
user must ensure that the panel being controlled does indeed ignore extra pixel clocks at the end of  
each line when a panel with line widths that are non-multiple of 16 pixels are used.  
The user must add extra space at the end of the frame buffer. The LCD’s DMA may overshoot the  
end of the frame buffer by one burst cycle (4-word read). The LCD’s DMA reads these extra  
values, but they are flushed from the input FIFO each time the frame clock is pulsed. The user must  
ensure that the four words immediately following the end of the frame buffer reside in legal  
memory space (do not cause a bus error if read). Since the LCD does not alter this memory (only  
reads are performed), these locations can be used for data storage unrelated to the LCD.  
The following equations are used to calculate the total frame buffer size in bytes that is accessed by  
the DMA based on varying pixel size encodings and screen sizes. The first term in the equations  
represents the size of the palette buffer, the second term is the add-on for the DMA overshoot at the  
end of the frame buffer, and the third term is the size required for the encoded pixel values. Note  
that for dual-panel mode, the frame buffer size is equally distributed between the two DMA  
channels and that DMA channel 2’s buffer is either 32 or 512 bytes smaller (no palette buffer; that  
is, the first term in the equations is deleted).  
Line(sXColumns)  
4 bits/pixel:  
FrameBufferSize = 32 + 16 + --------------------------------------------------- + (2(nXLines))  
2
8 bits/pixel:  
FrameBufferSize = 512 + 16 + (Line(sXColumns)) + (nXLines)  
12 or 16 bits/pixel:  
FrameBufferSize = 32 + 16 + 2(Line(sXColumns))  
Where n = 0 to 15 and is the number of extra “dummy” pixels required per line to make pixels/line  
an even multiple of sixteen.  
Note: The base address of the frame buffer must start on even 4-word boundaries (the four least  
significant address bits <3:0> must be zero).  
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11.7.1.3  
Input FIFO  
Data from the LCD’s DMA is directed either to the palette or the input FIFO. The direction of data  
flow is switched whenever the LCD controller is first enabled and by each frame pulse. After the  
LCD controller is configured and enabled, the first 32 (4-, 12-, and 16-bits/pixel) or 512  
(8-bit/pixel) bytes supplied by the DMA are sent to the palette. All subsequent encoded pixel data  
is sent to the FIFO. After an entire frame of pixels has been processed, the frame clock pin is  
pulsed to denote the start of the next frame. This signal is also used to change the direction of DMA  
input data from the FIFO back to the palette. A modulus of 8 (4-, 12-, and 16-bits/pixel) or 128  
(8-bits/pixel) is used to count when loading the palette RAM, depending on the pixel bit size shown  
above. A 7-bit counter is loaded each time a frame clock pulse occurs or the LCD is enabled, and is  
decremented each time a word is stored to the palette (two palette entries). When the counter wraps  
around to zero, the data input from the DMA is switched back to the FIFO.  
The LCD controller contains a 5-entry x 32-bit wide input FIFO that is used to store encoded pixels  
fetched from the frame buffer. The FIFO signals a service request to the DMA whenever four  
entries of the FIFO are empty. In turn, the DMA automatically fills the FIFO with a 4-word burst.  
Pixel data from the frame buffer remains packed within individual 32-bit words when it is loaded  
into the FIFO. The LCD controller’s port size is 32 bits wide to accommodate the heavy data flow  
from the frame buffer. Depending on the number of bits per pixel, as words are taken from the  
bottom of the FIFO, they are unpacked and supplied to the lookup palette in nibbles (4 bits/pixel)  
or bytes (8 bits/pixel) to the dither logic (12 bits/pixel), or directly to the pins in half-word  
increments (16 bits/pixel).  
Each time a word is taken from the bottom of the FIFO, the entry is invalidated and all data in the  
FIFO moves down one position. When four entries are empty, a service request is issued to the DMA.  
11.7.1.4  
Lookup Palette  
The encoded pixel data taken from the bottom entry of the input FIFO is used as an address to  
index and select individual palette locations. Four-bit pixel encodings address 16 locations and  
8-bit pixel encodings select any of the 256 palette entries. Note that the user may program 1, 2, and  
3 bits/pixel as well by zeroing out the upper 3, 2 or 1 bits of each encoded pixel value in the frame  
buffer, respectively. However, for 1, 2, and 3 bits/pixel, the encoded pixel size remains at 4 bits  
within the frame buffer and within the LCD controller’s input FIFO.  
Once a palette entry is selected by the encoded pixel value, the contents of the entry is sent to the  
color/gray-scale space/time base dither circuit. In color mode, the value within the palette is made up  
of three 4-bit fields, one for each color component – red, green, and blue. In monochrome mode, only  
one 4-bit value is present (see Figure 11-3). For both modes, the 4-bit values represent one of 15  
intensity levels. For color operation, an individual frame is limited to a selection of 256 colors (the  
number of palette entries). However, the LCD controller is capable of generating a total of 3375  
colors (15 levels per color ^ 3 colors = 3375). When 12 or 16 bits per pixel mode is enabled, the  
palette is bypassed. For passive displays, 12-bit pixels are sent directly to the dither logic; for active  
displays, 16-bit pixels are sent to the output FIFO to be driven directly to the LCD’s data pins.  
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Peripheral Control Module  
11.7.1.5  
Color/Gray-Scale Dithering  
For passive displays, entries selected from the lookup palette are sent to the color/gray-scale  
space/time base dither generator. Each 4-bit value is used to select one of 15 intensity levels. Note  
that two of the 16 dither values are identical (always high). The color/gray intensity is controlled by  
turning individual pixels on and off at varying periodic rates. For some screens, more intense  
colors/grays are produced by making the average time the pixel is high longer than the average  
time it is low, while other screens produce more intense colors/grays when the average time the  
pixel is low is longer. The user should program the palette appropriately depending on whether a  
one on the pixel line turns the pixel on or off. The dither generator also uses the intensity of  
adjacent pixels in its calculations to give the screen image a smooth appearance. The proprietary  
dither algorithm is optimized to provide a range of intensity values that match the eye’s visual  
perception of color/gray gradations. In color mode, three separate dither blocks are used to process  
the three color components: red, green, and blue. Table 11-7 summarizes the duty cycle and  
resultant intensity level for all 15 color/gray-scale levels.  
Table 11-7. Color/Gray-Scale Intensities and Modulation Rates  
Dither Value  
Intensity  
Modulation Rate  
(4-Bit Value from Palette)  
(0% Is Black)  
(Ratio of ON to ON+OFF Pixels)  
0000  
0001  
0010  
0011  
0100  
0101  
0110  
0111  
1000  
1001  
1010  
1011  
1100  
1101  
1110  
1111  
0.0%  
11.1%  
20.0%  
26.7%  
33.3%  
40.0%  
44.4%  
50.0%  
55.6%  
60.0%  
66.6%  
73.3%  
80.0%  
88.9%  
100.0%  
100.0%  
0
1/9  
1/5  
4/15  
3/9  
2/5  
4/9  
1/2  
5/9  
3/5  
6/9  
11/15  
4/5  
8/9  
1
1
11.7.1.6  
Output FIFO  
The LCD controller contains a 19-entry x 16-bit wide output FIFO that is used to store pixel pin data  
before it is driven out to the pins. Each time a modulated pixel value is output from the dither  
generator, it is placed into a serial shifter. The size of the shifter is controlled by programming the  
color/monochrome select and single- and dual-panel, double pixel data, and passive/active select bits  
in the LCD’s control registers and the pixel bit size within palette entry 0 in the frame buffer. The  
shifter can be configured to be 4, 8, or 16 bits wide. Four pins are used for single-panel monochrome  
screens; 8 pins are used for single- and dual-panel monochrome screens as well as single-panel color  
displays; 12 pins are used for active displays; and 16 pins are used for dual-panel color and active  
displays. Once the correct number of pixels have been placed within the shifter (4-, 8-, or 16-pixel  
values), the value is transferred to the top of the output FIFO. The value is then transferred down until  
it reaches the last empty location within the FIFO. Each time a value is taken from the bottom of the  
FIFO, the entry is invalidated and all data in the FIFO moves down one position.  
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Peripheral Control Module  
11.7.1.7  
LCD Controller Pins  
Pixel data is removed from the bottom of the output FIFO and is driven in parallel onto the LCD’s  
data lines on the edge selected by the pixel clock polarity (PCP) bit. For a 4-bit wide bus, data is  
driven onto the LCD data lines LDD<3:0> starting with the most significant bit. For an 8-bit wide  
bus, data is driven onto LDD<7:0>; for a 12-bit bus GPIO<5:2> and LDD<7:0>; and for a 16-bit  
bus GPIO<9:2> and LDD<7:0>. In monochrome dual-panel mode, the pixels for the upper half of  
the screen are driven onto LDD<3:0> and the lower half to LDD<7:4>. In color dual-panel mode,  
the upper panel pixels are driven onto LDD<7:0> and the lower panel pixels to GPIO<9:2>. Note  
that for a 4-bit wide bus, data is output via the LDD<3:0> pins and the LCD<7:4> pins are held low  
by the LCD controller. The user cannot use this pins as GPIOs in this mode. However, for a 12-bit  
wide bus, the user is free to use GPIO<9:6> as general- purpose I/O signals.  
When an entire line of pixels has been output to the LCD controller screen, the line clock pin (L_LCLK)  
is toggled. Likewise, when an entire frame of pixels has been output to the LCD controller screen, the  
frame clock pin (L_FCLK) is toggled. To prevent a dc charge from building within a passive display, its  
power and ground supplies must be switched periodically. The LCD controller signals the display to  
switch the polarity by toggling the ac bias pin (L_BIAS). The user can control the frequency of the bias  
pin by programming the number of line clock transitions between each toggle.  
When active display mode is enabled, the timing of the pixel, line, and frame clocks and the ac bias  
pin changes. The pixel clock transitions continuously in this mode as long as the LCD is enabled. The  
ac bias pin functions as an output enable. When it is asserted, the display latches data from the LCD’s  
pins using the pixel clock. The line clock pin is used as the horizontal synchronization signal  
(HSYNC) and the frame clock as the vertical synchronization signal (VSYNC). The timing of the line  
and frame clock pins is programmable to support both passive and active mode. Programming  
options include: waitstate insertion both at the beginning and end of each line and frame; pixel clock;  
line clock; frame clock; output enable signal polarity; and frame clock pulse width.  
When the LCD controller is disabled, control of all 12 of its pins is relinquished to the peripheral pin  
controller (PPC) unit to be used as general-purpose digital I/O pins that are noninterruptible. See the  
section 11.13 on page 184 for a description of the programming and operation of the PPC unit.  
11.7.2  
LCD Controller Register Definitions  
The LCD controller contains four control registers, four DMA address registers, and one status  
register. The control registers contain bit fields to enable and disable the LCD controller; to define  
the height and width of the screen being controlled; and to indicate single- versus dual-panel  
display mode, color versus monochrome mode, passive versus active display, polarity of the  
control pins, pulse width of the line and frame clocks, pixel clock and ac bias pin frequency. AC  
bias pin toggles per interrupt the number of waitstates to insert before and after each line, after each  
frame, and various interrupt masks. An additional control field exists to tune the DMA’s  
performance based on the type of memory system in which the SA-1100 is used. This field controls  
the placement of a minimum delay between each LCD DMA request to ensure enough bus  
bandwidth is given to other ARM system bus masters for accesses.  
The DMA address registers are used to define the base addresses of the off-chip frame buffers and to  
which address the DMA is currently pointing. Both of these registers exist for DMA channels 1 and 2.  
The status registers contain bits that signal input and output FIFO overrun and underrun errors,  
DMA bus errors, when the DMA base address can be reprogrammed, when the last active frame  
has completed after the LCD is disabled, and each time the ac bias pin has toggled a programmed  
number of times. Each of these hardware-detected events signals an interrupt request to the  
interrupt controller.  
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Peripheral Control Module  
11.7.3  
LCD Controller Control Register 0  
LCD controller control register 0 (LCCR0) contains 10 bit fields that are used to control various  
functions within the LCD controller.  
11.7.3.1  
LCD Enable (LEN)  
The LCD enable (LEN) bit is used to enable and disable all LCD controller operation. When  
LEN=0, the LCD controller is disabled and control of all 12 of its pins is given to the peripheral pin  
controller (PPC) unit to be used as general-purpose I/O (noninterruptible). When LEN=1, the LCD  
controller is enabled. Note that all other control registers should be initialized before setting LEN.  
The user can program LCCR0 last, and configure all 10 bit fields at the same time via a word write  
to the register. If the user clears LEN while the LCD controller is enabled, it will complete  
transmission of the current frame before being disabled. Completion of the current frame is  
signalled by the LCD when it sets the LCD disable done flag (LDD) within the LCD status register  
that generates an interrupt request. The user should use a read-modify-write procedure to clear  
LEN because the other bit-fields within LCCR0 continue to be used by the LCD controller after  
LEN is cleared until the frame that is currently in progress completes. When the LCD controller is  
disabled, control of all 12 of its pins is given to the peripheral pin controller (PPC) so that they may  
be used for general-purpose input and output (noninterruptible). See the Section 11.13, “Peripheral  
Pin Controller (PPC)” on page 11-184 for a description of the PPC.  
11.7.3.2  
11.7.3.3  
Color/Monochrome Select (CMS)  
The color/monochrome select (CMS) bit selects whether the LCD controller operates in color or  
monochrome mode. When CMS=0, color mode is selected, palette entries are 12 bits wide (4 bits  
per color), 8 data pins are enabled for single-panel mode, 16 data pins are enabled for dual-panel  
mode (GPIO pins 2..9 are used as the extra 8 data output pins), and all three dither blocks are used,  
one each for the red, green, and blue pixel components. When CMS=1, monochrome mode is  
selected, palette entries are 4 bits wide (15 levels of gray-scale), 4 or 8 data pins are enabled for  
single-panel mode, and 8 data pins are enabled for dual-panel mode.  
Single-/Dual-Panel Select (SDS)  
In passive mode (PAS=0), the single-/dual-panel select (SDS) bit is used to select the type of  
display control that is implemented by the LCD screen. When SDS=0, single-panel operation is  
selected (pixels presented to screen a line at a time), and when SDS=1, dual-panel operation is  
selected (pixels presented to screen two lines at a time). Single-panel LCD drivers have one  
line/row shifter and driver for pixels, and one line pointer; dual-panel LCD controller drivers have  
two line/row shifters (one for the top half of the screen, one for the bottom), and two line pointers  
(one for the top half of the screen, one for the bottom). When dual-panel mode is programmed,  
both of the LCD controller’s DMA channels are used. DMA channel 1 is used to load the palette  
RAM from the frame buffer and to drive the upper half of the display, and DMA channel 2 drives  
the lower half. The two channels alternate when fetching data for both halves of the screen, placing  
encoded pixel values within the two separate input FIFOs. When programming dual-panel  
operation, the user must perform the following sequence in order: disable the LCD (LEN=0),  
program dual-panel mode (SDS=0->1), write the upper panel DMA base address, write the lower  
panel DMA base address, and enable the LCD (LEN=0->1). When dual-panel operation is enabled,  
the LCD controller doubles its pin uses; thus, for monochrome screens 8 pins are used, and for  
color screens, 16 pins are used.  
11-26  
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Peripheral Control Module  
Table 11-8 shows the LCD data pins and GPIO pins used for each mode of operation and the  
ordering of pixels delivered to a screen for each mode of operation. Figure 11-8 shows the LCD  
data pin pixel ordering. Note that when dual-panel color operation is enabled, the user must  
configure GPIO pins 2 through 9 as outputs by setting bits 2..9 within the GPIO pin direction  
register (GPDR) and GPIO alternate function register (GAFR). See the Section 9.1,  
“General-Purpose I/O” on page 9-1 for configuration information. Also note that SDS is ignored in  
active mode (PAS=1).  
.
Table 11-8. LCD Controller Data Pin Utilization  
Color/  
Single/  
Passive/  
Active Panel  
Monochrome  
Dual Panel  
Panel  
Screen Portion  
Pins  
Monochrome  
Monochrome  
Monochrome  
Single  
Single  
Dual  
Passive  
Whole  
LDD<3:0>  
1
Passive  
Passive  
Whole  
Top  
LDD<7:0>  
LDD<3:0>  
LDD<7:4>  
LDD<7:0>  
LDD<7:0>  
Bottom  
Whole  
Top  
Color  
Color  
Single  
Dual  
Passive  
Passive  
Bottom  
Whole  
GPIO<9:2>  
Color  
Single  
Active  
GPIO<9:2>,  
LDD<7:0>  
1
Double-pixel data mode (DPD) = 1.  
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Figure 11-8. LCD Data-Pin Pixel Ordering  
Top Left Corner of Screen  
Column 0 Column 1 Column 2 Column 3 Column 4 Column 5 Column 6 Column 7 Column 8  
Row 0  
Row 1  
Row 2  
Row 3  
LDD<0> LDD<1> LDD<2> LDD<3> LDD<0> LDD<1> LDD<2> LDD<3> LDD<0>  
LDD<0> LDD<1> LDD<2> LDD<3> LDD<0> LDD<1> LDD<2> LDD<3> LDD<0>  
LDD<0> LDD<1> LDD<2> LDD<3> LDD<0> LDD<1> LDD<2> LDD<3> LDD<0>  
LDD<0> LDD<1> LDD<2> LDD<3> LDD<0> LDD<1> LDD<2> LDD<3> LDD<0>  
Passive Monochrome Single-Panel Display Pixel Ordering  
Top Left Corner of Screen  
Column 0 Column 1 Column 2 Column 3 Column 4 Column 5 Column 6 Column 7 Column 8  
Row 0  
Row 1  
Row 2  
Row 3  
LDD<0> LDD<1> LDD<2> LDD<3> LDD<4> LDD<5> LDD<6> LDD<7> LDD<0>  
LDD<0> LDD<1> LDD<2> LDD<3> LDD<4> LDD<5> LDD<6> LDD<7> LDD<0>  
LD<0>  
LDD<1> LDD<2> LDD<3> LDD<4> LDD<5> LDD<6> LDD<7> LDD<0>  
LDD<0> LDD<1> LDD<2> LDD<3> LDD<4> LDD<5> LDD<6> LDD<7> LDD<0>  
Passive Monochrome Single-Panel Double-Pixel Display Pixel Ordering  
Top Left Corner of Screen  
Column 0 Column 1 Column 2 Column 3 Column 4 Column 5 Column 6 Column 7 Column 8  
Row 0  
Row 1  
LDD<0> LDD<1>  
LDD<3>  
LDD<2>  
LDD<0>  
LDD<2> LDD<3> LDD<0>  
LDD<1>  
LDD<0> LDD<1> LDD<2> LDD<3> LDD<0> LDD<1> LDD<2> LDD<3> LDD<0>  
LDD<4> LDD<5>  
LDD<7>  
LDD<6>  
LDD<4>  
LDD<6> LDD<7> LDD<4>  
Row n/2  
LDD<5>  
LDD<4> LDD<5> LDD<6> LDD<7> LDD<4> LDD<5> LDD<6> LDD<7> LDD<4>  
Row n/2+1  
Passive Monochrome Dual-Panel Display Pixel Ordering  
n = # of rows  
Top Left Corner of Screen  
Column 0 Column 0 Column 0 Column 1 Column 1 Column 1 Column 2 Column 2 Column 2  
Red Blue Red Blue  
Red Blue Green Green  
Green  
Row 0  
Row 1  
Row 2  
Row 3  
LDD<7> LDD<6> LDD<5> LDD<4> LDD<3> LDD<2> LDD<1> LDD<0> LDD<7>  
LDD<7> LDD<6> LDD<5> LDD<4> LDD<3> LDD<2> LDD<1> LDD<0> LDD<7>  
LDD<7> LDD<6> LDD<5> LDD<4> LDD<3> LDD<2> LDD<1> LDD<0> LDD<7>  
LDD<7> LDD<6> LDD<5> LDD<4> LDD<3> LDD<2> LDD<1> LDD<0> LDD<7>  
Passive Color Single-Panel Display Pixel Ordering  
Top Left Corner of Screen  
Column 0 Column 0  
Red  
Green  
Column 2 Column 2  
Green  
Blue  
Column 4 Column 5 Column 5  
Blue Red  
Green  
Row 0  
LDD<7> LDD<6>  
LDD<0> LDD<7>  
LDD<1> LDD<0> LDD<7>  
Row 1  
LDD<7> LDD<6>  
LDD<0> LDD<7>  
LDD<1> LDD<0> LDD<7>  
Row n/2  
GPIO<9> GPIO<8>  
GPIO<2> GPIO<9>  
GPIO<2> GPIO<9>  
GPIO<3> GPIO<2> GPIO<9>  
GPIO<3> GPIO<2> GPIO<9>  
Row n/2+1 GPIO<9> GPIO<8>  
n = # of rows  
Passive Color Dual-Panel Display Pixel Ordering  
11-28  
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11.7.3.4  
LCD Disable Done Interrupt Mask (LDM)  
The LCD disable done interrupt mask (LDM) bit is used to mask or enable interrupt requests that  
are asserted after the LCD is disabled and the frame currently being output to the pins has  
completed. When LDM=0, the interrupt is enabled, and whenever the LCD disable done (LDD)  
status bit within the LCD status register (LCSR) is set (one), an interrupt request is made to the  
interrupt controller. When LDM=1, the interrupt is masked and the state of the LDD status bit is  
ignored by the interrupt controller. Note that programming LDM=1 does not affect the current state  
of LDD or the LCD controller’s ability to set and clear LDD; it only blocks the generation of the  
interrupt request. This interrupt is particularly useful when the user needs to ensure the LCD has  
been disabled and the current frame that is being output to the pins has completed, before entering  
sleep mode. If the user disables the LCD, but does not need to enter sleep mode, this interrupt can  
be masked using LDM.  
11.7.3.5  
Base Address Update Interrupt Mask (BAM)  
The base address update interrupt mask (BAM) bit is used to mask or enable interrupt requests that  
are asserted at the beginning of each frame when the LCD’s base address pointer is transferred to  
the current address pointer within the LCD’s DMA. When BAM=0, the interrupt is enabled, and  
whenever the base address update (BAU) status bit within the LCD status register (LCSR) is set  
(one) an interrupt request is made to the interrupt controller. When BAM=1, the interrupt is masked  
and the state of the BAU status bit is ignored by the interrupt controller. Note that programming  
BAM=1 does not affect the current state of BAU or the LCD controller’s ability to set and clear  
BAU; it only blocks the generation of the interrupt request. Note that this interrupt mask is  
particularly useful when the user wishes to enter idle mode to turn off the CPU and to display the  
same image (the off-chip frame buffer data does not change). By masking the BAU interrupt, the  
SA-1100 is not forced out of idle mode at the end of each frame.  
11.7.3.6  
Error Interrupt Mask (ERM)  
The error interrupt mask (ERM) bit is used to mask or enable interrupt requests that are asserted  
whenever a bus error or input/output FIFO over/underrun error occurs. When ERM=0, all error  
interrupts are enabled, and whenever the bus error (BER) status bit or any of the input/output FIFO  
over/underrun (IOL, IUL, IOU, IUU, OOL, OUL, OOU, OUU) status bits within the LCD status  
register (LCSR) are set (one), an interrupt request is made to the interrupt controller. When  
ERM=1, error interrupts are masked; the state of all of the error status bits (BER, IOL, IUL, IOU,  
IUU, OOL, OUL, OOU, OUU) are ignored by the interrupt controller. Note that programming  
ERM=1 does not affect the current state of these status bits or the LCD controller’s ability to set  
and clear them; it only blocks the generation of the interrupt requests.  
11.7.3.7  
Passive/Active Display Select (PAS)  
The passive/active display select (PAS) bit selects whether the LCD controller operates in passive  
(STN) or active (TFT) display control mode. When PAS=0, passive or STN mode is selected, all  
LCD data flow operates normally (including the use of the LCD’s dither logic), and all LCD  
controller pin timing operates as described in the preceding sections.  
When PAS=1, active or TFT mode is selected. For 4- and 8-bit per pixel modes, pixel data is  
transferred via the DMA from off-chip memory to the input FIFO, is unpacked and used to select an  
entry from the palette, just like passive mode. However, the value read from the palette bypasses the  
LCD’s dither logic, and is sent directly to the output FIFO to be output on the LCD’s data pins. This  
12-bit value output to the pins represents 4 bits of red, 4 bits of green, and 4 bits of blue data. For  
12- and 16-bit pixel encoding mode, the pixel size within the frame buffer is increased to 16 bits.  
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Peripheral Control Module  
Thus two 16-bit values are packed into each word in the frame buffer. Each 16-bit value is transferred  
via the DMA from off-chip memory to the input FIFO. Unlike 4- and 8-bit per pixel modes, the 16-bit  
value bypasses both the palette and the dither logic, and is placed directly in the output FIFO to be  
output on the LCD’s data pins. Increasing the size of the pixel representation allows a total of 64K  
colors to be generated. This 16-bit value output to the pins can be organized into one of three RGB  
color formats: 6 bits of red, 5 bits of green, and 5 bits of blue data; 5 bits of red, 6 bits of green, and 5  
bits of blue data; 5 bits of red, 5 bits of green, and 6 bits of blue data, as specified by the user. Note  
that the pin timing of the LCD changes when active mode is selected. Timing of each pin is described  
in subsequent bit-field sections for both passive and active mode. Additionally, the LCD controller  
can be configured in active color display mode and used with an external DAC and optionally an  
external palette to drive a video monitor. Note that only monitors that implement the RGB data format  
can be used; the LCD controller does not support the NTSC standard.  
Figure 11-9 shows which bits within each frame buffer entry (for 16-bit/pixel mode) and which bits  
within a selected palette entry (for 4- and 8-bit/pixel mode) are sent to the individual LCD data  
pins. In active mode, GPIO pins 2..9 are also used. Note that the user must configure GPIO pins  
2..5 as outputs (for 4- and 8-bit/pixel mode), and GPIO pins 2..9 as outputs (for 16-bit/pixel mode)  
by setting the appropriate bits within the GPIO pin direction register (GPDR) and GPIO alternate  
function register (GAFR). See the General-Purpose I/O section for configuration information. If  
GPDR<6:9> = GAFR<6:9> = 4’hF in 4- or 8-bit/pixel mode, then GPIO<6:9> are pulled low  
during LCD operation in active mode. However, the user is free to clear GAFR<6:9>, allowing the  
GPIO unit to assume control of these pins to be used as normal digital I/Os. In general, the user  
may clear any number of GAFR bits 2..9, to allow the GPIO unit to assume control of unused  
GPIO pins for normal digital I/O depending on the required number of data pins.  
If the panel that is being controlled contains more data pin inputs than 16, the user may still use the  
SA-1100’s LCD controller, but the panel will be limited to a total of 64 K colors. If the user wishes  
to maintain the panel’s full range of colors and increase the granularity of the spectrum, the LCD’s  
16 data pins should be interfaced to the panel’s most significant R, G, and B pixel data input pins  
and the least significant R, G, and B data pins should be tied either high or low. If instead, the user  
wishes to maintain the granularity of the spectrum and limit the overall range of colors possible, the  
LCD’s 16 data pins should be interfaced to the panel’s least significant R, G, and B pixel data input  
pins and the most significant data pins should again be tied either high or low.  
Figure 11-9. Frame Buffer/Palette Bits Output to LCD Data Pins in Active Mode  
16-Bit/Pixel Mode  
Frame Buffer Entry  
R<5> R<4> R<3> R<2> R<1> R<0> G<4> G<3> G<2> G<1> G<0> B<4>  
R<4> R<3> R<2> R<1> R<0> G<5> G<4> G<3> G<2> G<1> G<0> B<4>  
B<3>  
B<3>  
B<3>  
3
B<2> B<1>  
B<2> B<1>  
B<2> B<1>  
B<0>  
B<0>  
B<0>  
0
R<4> R<3> R<2> R<1> R<0> G<4> G<3> G<2> G<1> G<0> B<5>  
B<4>  
4
Bit  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
2
1
GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO  
LDD  
<7>  
LDD  
<6>  
LDD  
<5>  
LDD  
<4>  
LDD  
<3>  
LDD  
<2>  
LDD  
<1>  
LDD  
<0>  
Data  
Pin  
<9>  
<8>  
<7>  
<6>  
<5>  
<4>  
<3>  
<2>  
4- or 8-Bit/Pixel Mode  
Selected Palette Entry  
R<3> R<2> R<1> R<0> G<3> G<2> G<1> G<0> B<3>  
B<2> B<1>  
B<0>  
0
1
Bit  
VSS  
VSS  
VSS  
VSS  
11  
10  
9
8
7
6
5
4
3
2
1
GPIO GPIO GPIO GPIO GPIO GPIO GPIO GPIO  
<9> <8> <7> <6> <5> <4> <3> <2>  
LDD  
<7>  
LDD  
<6>  
LDD  
<5>  
LDD  
<4>  
LDD  
<3>  
LDD  
<2>  
LDD  
<1>  
LDD  
<0>  
Data  
Pin  
1 GPIO pins 6..0 are grounded by the LCD in this mode. However, if GAFR bit 6..9 are cleared within the system control module,  
these pins can be used as normal GPIO pins.  
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11.7.3.8  
Big/Little Endian Select (BLE)  
The big/little endian select (BLE) bit selects whether the LCD controller views external memory  
organization of the frame buffer as big or little endian. When BLE=0, little endian mode is selected  
and pixel data is organized within the off-chip frame buffer as shown in Figure 11-4 through  
Figure 11-7. Pixels are packed into words starting with the least-significant nibble, byte, or  
half-word. When BLE=1, big endian mode is selected and pixel data is organized in memory  
starting with the most significant nibble, byte, or half-word. When BLE=1, palette entries are  
packed into half-words starting with the most significant half-word. Note that BLE does not affect  
the ordering of the 4-bit red/green/blue bit fields, the 4-bit monochrome field within each 16-bit  
palette entry, or the 2-bit pixel bit size (PBS) field contained with palette entry 0.  
11.7.3.9  
Double-Pixel Data (DPD) Pin Mode  
The double-pixel data (DPD) pin mode bit selects whether four or eight data pins are used to output  
pixel data to the LCD screen in single-panel monochrome mode. When DPD=0, LDD<3:0> pins  
are used to output 4-pixel values each pixel clock transition; when DPD=1, LDD<7:0> pins are  
used to output 8-pixel values each pixel clock. See the following table and figure for a comparison  
of how the LCD’s data pins are used in each of its display modes. Note that DPD does not affect  
dual-panel monochrome mode nor any of the color modes.  
11.7.3.10 Palette DMA Request Delay (PDD)  
The 8-bit palette DMA request delay (PDD) field is used to select the minimum number of memory  
controller clock cycles (half the frequency of the CPU clock) to wait between the servicing of each  
DMA request issued while the on-chip palette is loaded. When the palette is loaded at the beginning  
of every frame, either 32 or 512 bytes of data must be accessed by the LCD’s DMA. Since the LCD’s  
DMA is the highest priority master on the ARM system bus, other masters (such as the CPU) will be  
denied access to the bus and may be starved. Using PDD allows other masters to gain access of the  
bus in between palette DMA loads, so that they are not locked from accessing the bus for an  
unacceptable period of time. Note that PDD does not apply to normal input FIFO DMA requests for  
frame buffer information since these DMA requests do not occur back-to-back. The input FIFO DMA  
request rate is a function of the rate at which pixels are displayed on the screen.  
After a palette DMA burst cycle has completed, the value contained within PDD is loaded to a  
down counter that disables the palette from issuing another DMA request until the counter  
decrements to zero. This counter ensures that the LCD’s DMA does not fully consume the  
bandwidth of the SA-1100’s system bus. Once the counter reaches zero, any pending or future  
DMA requests by the palette cause the DMA to arbitrate for the ARM system bus (ASB). Once the  
DMA burst cycle has completed, the process starts over and the value in PDD is loaded to the  
counter to create another waitstate period, which disables the palette from issuing a DMA request.  
PDD can be programmed with a value that causes the FIFO to wait between 0 to 255 memory clock  
cycles after the completion of one DMA request to the start of the next request. When PDD=8’h00,  
the FIFO DMA request delay function is disabled. Note that waitstates are not inserted between  
DMA burst cycles that are used to fill the input FIFO with pixel data.  
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Peripheral Control Module  
The following table shows the location of all 10 bit-fields located in LCD control register 0  
(LCCR0). The user must program the control bits within all other control registers before setting  
LEN=1 (a word write can be used to configure LCCR0 while setting LEN after all other control  
registers have been programmed), and also must disable the LCD controller when changing the  
state of any control bit within the LCD controller. Note that writes to reserved bits are ignored and  
reads return zeros.  
Address: 0h B010 0000  
LCCR0: LCD Control Register 0  
Read/Write  
18 17  
PDD<7:4>  
Bit  
Reset  
Bit  
31  
30  
29  
0
28  
0
27  
0
26  
25  
24  
23  
22  
21  
0
20  
0
19  
0
16  
0
Reserved  
0
0
0
10  
0
0
0
0
0
0
0
15  
0
14  
13  
12  
0
11  
9
DPD  
0
8
BLE  
0
7
PAS  
0
6
Res.  
0
5
ERM  
0
4
BAM  
0
3
LDM  
0
2
SDS  
0
1
CMS  
0
0
LEN  
0
PDD<3:0>  
Reserved  
Reset  
0
0
0
Bit  
Name  
LEN  
Description  
0
LCD controller enable.  
0 – LCD controller disabled. Control of L_PCLK, L_LCLK, L_FCLK, L_BIAS, and the  
LDD<7:0> pins is given to the PPC unit to be used as general-purpose I/O pins.  
1 – LCD controller enabled.  
1
2
CMS  
SDS  
Color/monochrome select.  
0 – Color operation enabled.  
1 – Monochrome operation enabled.  
Single-/dual-panel display select.  
0 – Single-panel display enabled. LDD<3:0> used for monochrome, LDD<7:0> used for  
color.  
1 – Dual-panel display enabled. LDD<7:0> used for monochrome, LDD<7:0> and  
GPIO<9:2> used for color (user must also program GPDR and GAFR registers within  
the GPIO unit).  
Note: SDS is ignored in active mode (PAS=1). For dual-panel operation, the user must  
disable the LCD, set SDS, program the upper panel DMA base address, program the  
lower panel DMA base address, and enable the LCD.  
3
4
LDM  
BAM  
LCD disable done mask.  
0 – LCD disable done condition generates an interrupt (state of LDD status sent to the  
interrupt controller).  
1 – LCD disable done condition does not generate an interrupt (LDD status bit ignored).  
Base address update mask.  
0 – Base address update condition generates an interrupt (state of BAU status sent to  
the interrupt controller).  
1 – Base address update condition does not generate an interrupt (BAU status bit  
ignored).  
5
6
ERM  
Error mask.  
0 – Bus error and FIFO over/underrun errors generate an interrupt (state of BER, IOL,  
IUL, IOU, IUU, OOL, OUL, OUU status sent to the interrupt controller).  
1 – Bus error and FIFO over/underrun errors do not generate an interrupt (BER, IOL,  
IUL, IOU, IUU, OOL, OUL, OOU, OUU status bits ignored).  
Reserved.  
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Peripheral Control Module  
Bit  
Name  
PAS  
Description  
7
Passive/active display select.  
0 – Passive or STN display operation enabled. Dither logic is enabled.  
1 – Active or TFT display operation enable. Dither logic bypassed, pin timing changes to  
support continuous pixel clock, output enable, VSYNC, HSYNC signals.  
8
BLE  
Big/little endian select.  
0 – Little endian operation is selected, half-word palette buffer data is packed into  
individual words of memory starting with the least significant half-word, and frame buffer  
pixel data is packed into individual words of memory starting with the least significant  
nibble, byte, or half-word.  
1 – Big endian operation is selected, half-word palette buffer data is packed into  
individual words of memory starting with the most significant half-word, and frame buffer  
pixel data is packed into individual words of memory starting with the most significant  
nibble, byte, or half-word.  
9
DPD  
Double-pixel data pin mode.  
0 – In single-panel monochrome operation, four pixels are presented to LDD<3:0> each  
pixel clock.  
1 – In single-panel monochrome operation, eight pixels are presented to LDD<7:0>  
each pixel clock.  
Note: This bit is ignored in all other modes of operation except for single-panel  
monochrome.  
11..10  
Reserved.  
19..12 PDD  
Palette DMA request delay.  
Value (from 0 to 255) used to specify the number of memory controller clocks (half the  
speed of the CPU clock). The on-chip palette DMA request should be disabled after  
each DMA transfer to the palette. The clock count starts after the last write of each burst  
cycle. While the counter is decrementing, all DMA requests from the palette are masked.  
When the counter reaches zero, any pending or subsequent DMA requests are allowed  
to generate a 4-word burst. Programming PDD=8h’00 disables this function.  
31..20  
Reserved.  
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Peripheral Control Module  
11.7.4  
LCD Controller Control Register 1  
LCD controller control register 1 (LCCR1) contains four bit fields that are used as modulus values  
for a collection of down counters, each of which performs a different function to control the timing  
of several of the LCD’s pins.  
11.7.4.1  
Pixels Per Line (PPL)  
The pixels per line (PPL) bit-field is used to specify the number of pixels in each line or row on the  
screen. PPL is a 10-bit value that represents between 16 and 1024 pixels per line. PPL is used to  
count the correct number of pixel clocks that must occur before the line clock can be asserted. The  
user should program PPL with the desired number of pixels per line minus 16. Note that the bottom  
four bits of PPL are not implemented and therefore are not writable. Reads of these bits return  
zeros because the LCD controller only supports displays that are a multiple of 16 pixels wide.  
Many displays exist that are not a multiple of 16, but are able to ignore added pixels at the end of  
each line. For example, if the display being controlled is 250 pixels wide, the nearest greater  
multiple of 16 is 256. The user should program PPL to 256-16 = 240 (10’h0F0). In this case, the  
user must also add the appropriate number of “dummy” pixel values (between 1 and 15) to the  
frame buffer. Again, for a 250 pixel wide display, and if 4-bit/pixel mode is used, each line is 250  
nibbles or 125 bytes in length. The next nearest pixel boundary occurs at 256 pixels or nibbles (128  
bytes). Thus the user must start each new line in the frame buffer at multiples of 128 bytes by  
adding an extra 6 “dummy” pixels per line (3 bytes). Note that the user must also ensure that the  
display that is being controlled will ignore any additional pixel clocks at the end of each line  
because these “dummy” pixel values will be output to the display and the pixel clock will continue  
to transition until the PPL+16 value is reached.  
11.7.4.2  
Horizontal Sync Pulse Width (HSW)  
The 6-bit horizontal sync pulse width (HSW) field is used to specify the pulse width of the line  
clock in passive mode or horizontal synchronization pulse in active mode. L_LCLK is asserted  
each time a line or row of pixels is output to the display and a programmable number of pixel clock  
waitstates have elapsed. When line clock is asserted, the value in HSW is transferred to a 6-bit  
down counter, which uses the programmed pixel clock frequency to decrement. When the counter  
reaches zero, the line clock is negated. HSW can be programmed to generate a line clock pulse  
width ranging from 1 to 64 pixel clock periods. The user should program HSW with the desired  
number of pixel clocks minus one. Note that the pixel clock does not transition during the line  
clock pulse in passive display mode, but does transition in active display mode. Also note that the  
polarity (active and inactive state) of the line clock pin is programmed using the horizontal sync  
polarity (HSP) bit in LCCR3.  
11.7.4.3  
End-of-Line Pixel Clock Wait Count (ELW)  
The 8-bit end-of-line pixel clock wait count (ELW) field is used to specify the number of “dummy”  
pixel clocks to insert at the end of each line or row of pixels before pulsing the line clock pin. Once  
a complete line of pixels is transmitted to the LCD driver, the value in ELW is used to count the  
number of pixel clocks to wait before pulsing the line clock. ELW generates a wait period ranging  
from 1 to 256 pixel clock cycles. The user should program ELW with the desired number of pixel  
clocks minus one. Note that the pixel clock pin, L_PCLK, does not transition during the these  
“dummy” pixel clock cycles in passive display mode (pixel clock transitions continuously in active  
display mode).  
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Peripheral Control Module  
11.7.4.4  
Beginning-of-Line Pixel Clock Wait Count (BLW)  
The 8-bit beginning-of-line pixel clock wait count (BLW) field is used to specify the number of  
“dummy” pixel clocks to insert at the beginning of each line or row of pixels. After the line clock  
for the previous line has been negated, the value in BLW is used to count the number of pixel  
clocks to wait before starting to output the first set of pixels in the next line. BLW generates a wait  
period ranging from 1 to 256 pixel clock cycles. The user should program BLW with the desired  
number of pixel clocks minus one. Note that the pixel clock pin, L_PCLK, does not transition  
during these “dummy” pixel clock cycles in passive display mode (pixel clock transitions  
continuously in active display mode).  
The following table shows the location of the four bit fields located in LCD control register 1  
(LCCR1). The LCD controller must be disabled (LEN=0) when changing the state of any field  
within this register.  
Address: 0h B010 0020  
LCCR1: LCD Controller Control Register 1  
Read/Write  
Bit  
Reset  
Bit  
31  
30  
29  
28  
0
27  
0
26  
25  
24  
23  
22  
21  
0
20  
0
19  
0
18  
17  
16  
0
BLW  
ELW  
0
0
0
0
0
0
0
0
0
0
15  
0
14  
0
13  
0
12  
0
11  
0
10  
0
9
8
7
6
5
4
3
2
1
0
HSW  
PPL<9:4>  
PPL<3:0>  
Reset  
0
0
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
9..0  
PPL  
Pixels per line.  
Value (from 1 to 1024). Used to specify number of pixels contained within each line on  
the LCD display. Pixels/line = (PPL+16).  
Note that PPL<3:0> are not implemented but return zeros when read.  
15..10  
HSW  
ELW  
BLW  
Horizontal sync pulse width.  
Value (from 1 to 64). Used to specify number of pixel clock periods to pulse the line  
clock at the end of each line. HSYNC pulse width = (HSW+1).  
Note that pixel clock is held in its inactive state during the generation of the line clock in  
passive display mode and is permitted to transition in active display mode.  
23..16  
31..24  
End-of-line pixel clock wait count.  
Value (from 1 to 256). Used to specify number of pixel clock periods to add to the end of  
a line transmission before line clock is asserted. EOL = (ELW+1).  
Note that pixel clock is held in its inactive state during the end-of-line wait period in  
passive display mode and is permitted to transition in active display mode.  
Beginning-of-line pixel clock wait count.  
Value (from 1 to 256). Used to specify number of pixel clock periods to add to the  
beginning of a line transmission before the first set of pixels is output to the display.  
BOL wait = (BLW+1).  
Note that pixel clock is held in its inactive state during the beginning-of-line wait period  
in passive display mode and is permitted to transition in active display mode.  
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Peripheral Control Module  
11.7.5  
LCD Controller Control Register 2  
LCD controller control register 2 (LCCR2) contains four bit fields that are used as modulus values  
for a collection of down counters, each of which performs a different function to control the timing  
of several of the LCD’s pins.  
11.7.5.1  
Lines Per Panel (LPP)  
The lines per panel (LPP) bit field is used to specify the number of lines or rows present on the LCD  
panel being controlled. In single-panel mode, it represents the total number of lines for the entire LCD  
display. In dual-panel mode, it represents half the number of lines of the entire LCD display because  
it is split into two panels. LPP is a 10-bit value that represents between 1 and 1024 lines per screen.  
The user should program LPP with the desired height of the display minus one. LPP is used to count  
the correct number of line clocks that must occur before the frame clock can be pulsed.  
The LCD’s DMA may overshoot the end of frame buffer by one burst cycle (4-word read). The LCD’s  
DMA reads these extra values but they are flushed from the input FIFO each time the frame clock is  
pulsed. The user must ensure that the four words immediately following the end of the frame buffer  
reside in legal memory space (do not cause a bus error if read). Because the LCD does not alter this  
memory (only reads are performed), these locations can be used for data storage unrelated to the LCD.  
11.7.5.2  
Vertical Sync Pulse Width (VSW)  
The 6-bit vertical sync pulse width (VSW) field is used to specify the pulse width of the vertical  
synchronization pulse in active mode, or is used to add extra “dummy” line clock waitstates  
between the end and beginning of frame in passive mode.  
In active mode (PAS=1), L_FCLK is used to generate the vertical sync signal and is asserted each  
time the last line or row of pixels for a frame is output to the display and a programmable number  
of line clock waitstates have elapsed as specified by ELW. When L_FCLK is asserted, the value in  
VSW is transferred to a 6-bit down counter, which uses the line clock frequency to decrement.  
When the counter reaches zero, L_FCLK is negated. VSW can be programmed to generate a  
vertical sync pulse width ranging from 1 to 64 line clock periods. The user should program VSW  
with the desired number of line clocks minus one. Note that the line clock does not transition  
during generation of the vertical sync pulse. Also note that the polarity (active and inactive state) of  
the L_FCLK pin is programmed using the frame clock polarity (FCP) bit in LCCR3.  
In passive mode (PAS=0), VSW does not affect the timing of the L_FCLK pin, but rather can be  
used to add extra line clock waitstates between the end of each frame and the beginning of the next  
frame. When the last line clock of a frame is negated, the value in VSW is transferred to a 6-bit  
down counter that uses the line clock frequency to decrement. When the counter reaches zero, the  
next frame is permitted to begin. VSW can be programmed to generate from 1 to 64 dummy line  
clock periods between each frame in passive mode. The user should program VSW properly to  
ensure that enough waitstates occur between frames such that the LCD’s DMA is able to fully load  
the on-chip palette, as well as allowing a sufficient number of encoded pixel values to be input  
from the frame buffer, to be processed by the dither logic, and placed in the output FIFO, ready to  
be output to the LCD’s data pins. The number of waitstates required is system dependent. The  
factors that determine the number of waitstates include: palette buffer size (32 or 512 bytes),  
memory system speed (number of waitstates, burst speed, number of beats), and what value is  
programmed in the palette DMA request delay (PDD) bit-field in LCCR0. Note that the line clock  
pin does transition during the insertion of the line clock waitstate periods.  
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Peripheral Control Module  
VSW does not affect generation of the frame clock signal in passive mode. Passive LCD displays  
require that the frame clock is active on the rising edge of the first line clock pulse of each frame,  
with adequate setup and hold time. To meet this requirement, the LCD controller’s frame clock pin  
is asserted on the rising edge of the first pixel clock for each frame. The frame clock remains  
asserted for the remainder of the first line as pixels are output to the display and it is then negated  
on the rising edge of the first pixel clock of the second line of each frame.  
11.7.5.3  
End-of-Frame Line Clock Wait Count (EFW)  
The 8-bit end-of-frame line clock wait count (EFW) field is used in active mode (PAS=1) to  
specify the number of line clocks to insert at the end of each frame. Once a complete frame of  
pixels is transmitted to the LCD display, the value in EFW is used to count the number of line clock  
periods to wait. After the count has elapsed, the VSYNC (L_FCLK) signal is pulsed. EFW  
generates a wait period ranging from 0 to 255 line clock cycles (setting EFW=8’h00 disables the  
EOF wait count). Note that the line clock pin, L_LCLK, does not transition during the generation  
of the EFW line clock periods.  
In passive mode, EFW should be set to zero such that no end-of-frame waitstates are generated.  
VSW should be used exclusively in passive mode to insert line clock waitstates to allow the LCD’s  
DMA to fill the palette and process a number of pixels before the start of the next frame.  
11.7.5.4  
Beginning-of-Frame Line Clock Wait Count (BFW)  
The 8-bit beginning-of-frame line clock wait count (BFW) field is used in active mode (PAS + 1) to  
specify the number of line clocks to insert at the beginning of each frame. The BFW count starts  
just after the VSYNC signal for the previous frame has been negated. After this has occurred, the  
value in BFW is used to count the number of line clock periods to insert before starting to output  
pixels in the next frame. BFW generates a wait period ranging from 0 to 255 extra line clock cycles  
(BFW=8’h00 disables the BOF wait count). Note that the line clock pin, L_LCLK, does transition  
during the generation of the BFW line clock wait periods.  
In passive mode, BFW should be set to zero such that no beginning-of-frame waitstates are  
generated. VSW should be used exclusively in passive mode to insert line clock waitstates to allow  
the LCD’s DMA to fill the palette and process a number of pixels before the start of the next frame.  
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Peripheral Control Module  
The following table shows the location of the four bit fields located in LCD control register 2  
(LCCR2). The LCD controller must be disabled (LEN=0) when changing the state of any field  
within this register.  
Address: 0h B010 0024  
LCCR2: LCD Controller Control Register 2  
Read/Write  
Bit  
31  
30  
29  
28  
0
27  
0
26  
25  
24  
23  
22  
21  
0
20  
0
19  
0
18  
17  
16  
0
BFW  
EFW  
Reset  
0
-
0
14  
0
0
0
0
0
0
0
0
-
Bit  
15  
13  
0
12  
0
11  
0
10  
0
9
8
7
6
5
4
3
2
1
0
VSW  
LPP  
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
9..0  
LPP  
Lines per panel.  
Value (from 1 to 1024). Used to specify number of lines per panel. For single-panel  
mode, this represents the total number of lines on the LCD display; for dual-panel  
mode, this represents half the number of lines on the whole LCD display.  
Lines/panel = (LPP+1).  
15..10  
VSW  
Vertical sync pulse width.  
In active mode (PAS=1), value (from 1 to 64). Used to specify number of line clock  
periods to pulse the L_FCLK pin at the end of each frame after the end-of-frame wait  
(EFW) period elapses. Frame clock used as VSYNC signal in active mode.  
In passive mode (PAS=0), value (from 1 to 64). Used to specify number of extra line  
clock  
periods to insert after the end-of-frame. Note that the width of L_FCLK is not affected  
by VSW in passive mode and that line clock does not transition during the insertion of  
the extra line clock periods. Also note that both EFW and BFW should be set to zero in  
passive mode.  
VSYNC width = (VSW+1).  
23..16  
31..24  
EFW  
BFW  
End-of-frame line clock wait count.  
In active mode (PAS=1), value (from 0 to 255). Used to specify number of line clock  
periods to add to the end of each frame. Note that line clock does transition during the  
insertion of the extra line clock periods. EFW should be cleared to zero (disabled) in  
passive mode.  
Beginning-of-frame line clock wait count.  
In active mode (PAS=1), value (from 0 to 255). Used to specify number of line clock  
periods to add to the beginning of a frame before the first set of pixels is output to the  
display. Note that line clock does transition during the insertion of the extra line clock  
periods. BFW should be cleared to zero (disabled) in passive mode.  
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Peripheral Control Module  
11.7.6  
LCD Controller Control Register 3  
LCD controller control register 3 (LCCR3) contains seven different bit fields that are used to  
control various functions within the LCD controller.  
11.7.6.1  
Pixel Clock Divider (PCD)  
The 8-bit pixel clock divider (PCD) field is used to select the frequency of the pixel clock. PCD can  
be any value from 1 to 225 (0 is illegal) and is used to generate a range of pixel clock frequencies  
from CCLK/6 to CCLK/514 (where CCLK is the programmed frequency of the CPU clock). The  
pixel clock frequency should be adjusted to meet the required screen refresh rate. The refresh rate  
depends on: the number of pixels for the target display; whether single- or dual-panel mode is  
selected; whether monochrome or color mode is selected; the number of pixel clock waitstates  
programmed at the beginning and end of each line; the number of line clocks inserted at the  
beginning and end of each frame; the width of the VSYNC signal in active mode or VSW line  
clocks inserted in passive mode; and the width of the frame clock or HSYNC signal. All of these  
factors alter the time duration from one frame transmission to the next. Different display  
manufacturers require different frame refresh rates depending on the physical characteristics of the  
display. PCD is used to alter the pixel clock frequency in order to meet these requirements. The  
frequency of the pixel clock for a set PCD value or the required PCD value to yield a target pixel  
clock frequency can be calculated using the two following equations. Note that programming PCD  
= 8’h00 is illegal.:  
CCLK  
PixelClock = -----------------------------  
2(PCD + 2)  
CCLK  
PCD = ------------------------------------- 2  
2(PixelClock)  
11.7.6.2  
AC Bias Pin Frequency (ACB)  
The 8-bit ac bias frequency (ACB) field is used to specify the number of line clock periods to count  
between each toggle of the ac bias pin (L_BIAS). In passive mode, after the LCD controller is  
enabled, the value in ACB is loaded to an 8-bit down counter and the counter begins to decrement  
using the line clock. When the counter reaches zero, it stops, the state of L_BIAS is reversed, and the  
whole procedure starts again. The number of line clocks between each ac bias pin transition ranges  
from 1 to 256. The user should program ACB with the desired number of line clocks minus one.  
This pin is used by the LCD display to periodically reverse the polarity of the power supplied to the  
screen to eliminate dc offset. If the LCD display being controlled has its own internal means of  
switching its power supply, ACB should be set to its maximum value to reduce power consumption  
(8’hFF). Note that the ACB bit field has no effect on L_BIAS in active mode. Because the pixel  
clock transitions continuously in active mode, the ac bias pin is used as an output enable signal. It  
is asserted automatically by the LCD controller in active mode whenever pixel data is driven out to  
the data pins to signal the display when it may latch pixels using the pixel clock.  
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Peripheral Control Module  
11.7.6.3  
AC Bias Pin Transitions Per Interrupt (API)  
The 4-bit ac bias pin transitions per interrupt (API) field is used to specify the number of L_BIAS  
pin transitions to count before setting the ac bias count status (ACS) bit in the LCD controller  
status register that signals an interrupt request. After the LCD controller is enabled, the value in  
API is loaded to a 4-bit down counter and the counter decrements each time the ac bias pin is  
inverted. When the counter reaches zero, it stops and the ac bias count (ABC) bit is set in the status  
register. Once ABC is set, the 4-bit down counter is reloaded with the value in API, and is disabled  
until ABC is cleared. When ABC is cleared by the CPU, the down counter is enabled and again  
decrements each time the ac bias pin is inverted. The number of ac bias pin transitions between  
each interrupt request ranges from 0 to 15. Note that programming API=4’h0 disables the ac bias  
pin transitions per interrupt function.  
In active mode, L_BIAS is used as an output enable signal. However, signalling of the API interrupt  
may still occur. The ACB bit field can be used to count line clock pulses in active mode. When the  
programmed number of line clock pulses occurs, an internal signal is transitioned that is used to  
decrement the 4-bit counter used by the API interrupt logic. Once this internal signal transitions the  
programmed number of times, as specified by API, an interrupt is generated. The user should  
program API to zero if the API interrupt function is not required in active mode (PAS = 1).  
11.7.6.4  
Vertical Sync Polarity (VSP)  
The vertical sync polarity (VSP) bit is used to select the active and inactive states of the vertical sync  
signal in active display mode (PAS = 1), and the frame clock signal in passive display mode. When  
VSP=0, the L_FCLK pin is active high and inactive low. When VSP=1, the L_FCLK pin is active  
low and inactive high. In active display mode, the L_FCLK pin is forced to its inactive state while  
pixels are transmitted during the frame. After the end of the frame and a programmable number of  
line clocks periods occur (controlled by EFW), the L_FCLK pin is forced to its active state for a  
programmable number of line clocks (controlled by VSW), and is then again forced to its inactive  
state. In passive display mode, the L_FCLK pin is forced to its inactive state during the transmission  
of the second line of each frame through to the end of the frame. Frame clock is then forced to its  
active state on the rising edge of the first pixel clock of each frame. Frame clock remains active  
during the transmission of the entire first line of pixels in the frame and is then forced back to its  
inactive state on the rising edge of the first pixel clock of the second line of the frame.  
11.7.6.5  
Horizontal Sync Polarity (HSP)  
The horizontal sync polarity (HSP) bit is used to select the active and inactive states of the  
horizontal sync signal in active display mode, and the line clock signal in passive display mode.  
When HSP=0, the L_LCLK pin is active high and inactive low. When HSP=1, the L_LCLK pin is  
active low and inactive high. Both in active and passive display modes, the L_FCLK pin is forced  
to its inactive state whenever pixels are transmitted After the end of each line and a programmable  
number of pixel clock periods occur (controlled by ELW), the L_FCLK pin is forced to its active  
state for a programmable number of line clocks (controlled by HSW), and is then again forced to its  
inactive state.  
11.7.6.6  
Pixel Clock Polarity (PCP)  
The pixel clock polarity (PCP) bit is used to select which edge of the pixel clock data is driven out  
onto the LCD’s data pins. When PCP=0, data is driven onto the LCD’s data pins on the rising edge  
of the L_PCLK pin. When PCP=1, data is driven onto the LCD’s data pins on the falling edge of  
the L_PCLK pin.  
11-40  
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Peripheral Control Module  
11.7.6.7  
Output Enable Polarity (OEP)  
The output enable polarity (OEP) bit is used to select the active and inactive states of the output  
enable signal in active display mode. In this mode, the ac bias pin is used as an enable that signals the  
off-chip device when data is actively being driven out using the pixel clock. The pixel clock  
continuously toggles during operation of active mode (PAS=1). When OEP=0, the L_BIAS pin is  
active high and inactive low. When OEP=1, the L_BIAS pin is active low and inactive high. In active  
display mode, data is driven onto the LCD’s data pins on the programmed edge of the L_PCLK pin  
when L_BIAS is in its active state. Note that OEP does not affect L_BIAS in passive display mode.  
The following table shows the location of the seven different bit fields located in LCD controller  
control register 3 (LCCR3). The LCD controller must be disabled (LEN=0) when changing the state  
of any field within this register. Note that writes to reserved bits are ignored and reads return zeros.  
Address: 0h B010 0028  
LCCR3: LCD Controller Control Register 3  
Read/Write  
Bit  
31  
30  
29  
28  
27  
26  
25  
24  
23  
OEP  
0
22  
PCP  
0
21  
HSP  
0
20  
VSP  
0
19  
0
18  
17  
16  
0
Reserved  
API  
Reset  
0
-
0
0
0
12  
0
0
0
0
0
0
0
-
Bit  
15  
14  
0
13  
0
11  
0
10  
0
9
8
7
0
6
0
5
0
4
3
2
1
0
ACB  
PCD  
Reset  
0
0
0
0
0
0
0
0
Bit  
Name  
Description  
7..0  
PCD  
Pixel clock divisor.  
Value (from 0 to 255). Used to specify the frequency of the pixel clock based on the  
CPU clock (CCLK) frequency. Pixel clock frequency can range from CCLK/6 to  
CCLK/514.  
Pixel Clock Frequency = CCLK/2(PCD+2).  
Note that PCD must be programmed with a value of 1 or greater (PCD = 8’h00 is illegal).  
AC bias pin frequency.  
15..8  
ACB  
Value (from 1 to 256). Used to specify the number of line clocks to count before  
transitioning the ac bias pin in passive mode (PAS=0). This pin is used to periodically  
invert the polarity of the power supply to prevent dc charge buildup within the display. If  
the passive display that is being controlled does not need to use L_BIAS, the user  
should program ACB to its maximum value (8’hFF) to conserve power. Note that ACB  
is ignored in active mode (PAS = 1).  
Number of line clocks/toggle of the L_BIAS pin = (ACB+1).  
AC bias pin transitions per interrupt.  
19..16  
API  
Value (from 0 to 15). Used to specify the number of ac bias pin transitions to count  
before setting the line count status (ABC) bit, signalling an interrupt request. Counter  
frozen when ABC is set and is restarted when ABC is cleared by software. This  
function is disabled when API=4’h0.  
20  
VSP  
Vertical sync polarity.  
0 – L_FCLK pin is active high and inactive low.  
1 – L_FCLK pin is active low and inactive high.  
Active mode: Vertical sync pulse active between frames, after end-of-frame wait period.  
Passive mode: Frame clock active during first line of each frame.  
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Peripheral Control Module  
Bit  
Name  
Description  
21  
HSP  
Horizontal sync polarity.  
0 – L_LCLK pin is active high and inactive low.  
1 – L_LCLK pin is active low and inactive high.  
Active and passive mode: horizontal sync pulse/line clock active between lines, after  
end-of-line wait period.  
22  
23  
PCP  
OEP  
Pixel clock polarity.  
0 – Data is driven on the LCD’s data pins on the rising edge of L_PCLK.  
1 – Data is driven on the LCD’s data pins on the falling edge of L_PCLK.  
Output enable polarity.  
0 – L_BIAS pin is active high and inactive low in active display mode and parallel data  
input mode.  
1 – L_BIAS pin is active low and inactive high in active display mode and parallel data  
input mode.  
In active display mode, data is driven out to the LCD’s data pins on programmed pixel  
clock edge when ac bias pin is active. Note that OEP is ignored in passive display  
mode.  
31..24  
Reserved.  
11.7.7  
LCD Controller DMA Registers  
The LCD controller has two fully independent DMA channels used to transfer frame buffer data for  
each frame displayed from off-chip memory to the LCD’s palette RAM and the input FIFO. DMA  
channel 1 is used for single-panel display mode and the upper screen in dual-panel mode. DMA  
channel 2 is used exclusively for the lower screen in dual-panel mode. Both DMA channels contain  
a base address pointer and current address pointer register. The LCD’s DMA engine has the highest  
priority to gain mastership of the SA-1100’s internal ARM system bus. The LCD is given highest  
priority to prevent other masters from starving the LCD screen (including the CPU).  
The two DMA channels use a separate set of base address and current address pointers. The user  
must initialize the base address pointer registers before enabling the LCD. Once enabled, the base  
address is transferred to the current address pointer.  
After the LCD is enabled, the input FIFO requests a DMA transfer and the DMA makes a 4-word  
burst access from off-chip memory using the address contained within the current address pointer.  
The pointer is incremented by 4 (bytes) each time a word is read from memory (bit 2 of the pointer  
is incremented). Each of the 4 words from the burst is loaded into the top of the input FIFO. The  
LCD then takes one value at a time from the bottom of the FIFO, unpacks it into individual  
encoded pixel values, and uses the values to index into the palette. Each time the input FIFO  
contains four empty entries, another DMA request is made and another 4-word burst is performed.  
To calculate the frame buffer end address, the DMA controller uses the values programmed in the  
pixels per line (PPL), lines per panel (LPP), single/dual screen select (SDS), color/monochrome  
select (CMS) bit fields, and double pixel data (DPD) bit fields within the control registers as well  
as the pixel bit size (PBS) field contained within the first entry of the palette buffer from the  
off-chip frame buffer. When the current address pointer reaches the calculated end of buffer  
address, the value in the base address pointer is again transferred to the current address pointer.  
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Peripheral Control Module  
11.7.8  
DMA Channel 1 Base Address Register  
DMA channel 1 base address register (DBAR1) is a 32-bit register that is used to specify the base  
address of the off-chip frame buffer for DMA channel 1. The base address pointer register can be  
both read and written. Addresses programmed in the base address register must be aligned on  
quadword boundaries; the least significant four bits (DBAR1<3:0>) must always be written with  
zeros. The user must initialize the base address register before enabling the LCD, and can also  
write a new value to it while the LCD is enabled to allow a new frame buffer to be used for the next  
frame. The user can change the state of DBAR1 while the LCD controller is active just after the  
base address update (BAU) status bit is set with the LCD’s status register, which generates an  
interrupt request. This status bit indicates that the value in the base address pointer has transferred  
to the current address pointer register and that it is safe to write a new base address value. DMA  
channel 1 is used to transfer frame buffer data from off-chip memory to the LCD’s input FIFO and  
the palette RAM for single-panel mode, and for the top half of the screen in dual-panel mode. For  
dual-panel operation, the user must perform the following sequence in order: disable the LCD  
(LEN=0), program dual panel mode (SDS= 0 1), write the upper panel DMA base address,  
write the lower panel DMA base address, enable the LCD (LEN= 0 1). Note that DBAR1 is not  
reset and must be initialized before enabling the LCD; question marks indicate that the values are  
unknown at reset.  
Address: 0h B010 0010  
DBAR1: DMA Channel 1 Base Address Register  
Read/Write  
Bit  
31  
30  
29  
28  
?
27  
26  
25  
24  
23  
22  
21  
20  
?
19  
?
18  
17  
16  
?
DMA Channel 1 Base Address Pointer  
Reset  
?
-
?
14  
?
?
?
?
9
?
8
?
7
?
6
?
?
?
-
Bit  
15  
13  
?
12  
?
11  
?
10  
?
5
4
3
2
1
0
DMA Channel 1 Base Address Pointer  
Reset  
?
?
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
Description  
31..0  
DBAR1  
DMA channel 1 base address pointer.  
Used to specify the base address of the frame buffer within off-chip memory. Value in  
DBAR1 is transferred to current address pointer register 1 when LCD is first enabled  
(LEN= 0 1) and when the current address pointer value equals the end-of-frame  
buffer. DBAR1 should be written only when the LCD is disabled or immediately after an  
interrupt is generated by the setting of the base address update (BAU) status bit. The  
base address must be on a quadword boundary; the user must always write bits 0  
through 3 to zero.  
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Peripheral Control Module  
11.7.9  
DMA Channel 1 Current Address Register  
DMA channel 1 current address register (DCAR1) is a 32-bit read-only register that is used by  
DMA channel 1 to keep track of the address of the DMA transfer currently in progress or the  
address of the next DMA transfer. Any time the LCD is first enabled (LEN= 0 1) or the value in  
the current address pointer register equals the calculated end address value, the contents of the base  
address pointer register is transferred to the current address pointer. This register can be read to  
determine the approximate line that the LCD controller is currently processing and driving out to  
the display. It is also useful to read this register just before writing the DMA’s base address pointer  
to ensure that the end of frame is not about to occur, which means that the base address pointer is  
about to be transferred to the current address pointer. Note that DCAR1 is a read-only register that  
is not reset and is not initialized until the LCD is first enabled, causing the contents of the base  
address register to be transferred to it; question marks indicate that the values are unknown at reset.  
.
Address: 0h B010 0014  
DCAR1: DMA Channel 1 Current Address Register  
Read-Only  
Bit  
31  
30  
29  
?
28  
?
27  
?
26  
25  
24  
23  
22  
21  
20  
?
19  
?
18  
?
17  
16  
?
DMA Channel 1 Current Address Pointer  
Reset  
?
-
?
?
?
9
?
8
?
7
?
6
?
?
1
?
-
Bit  
15  
14  
?
13  
?
12  
?
11  
?
10  
?
5
4
3
2
0
DMA Channel 1 Current Address Pointer  
Reset  
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
DCAR1  
Description  
31..0  
DMA channel 1 current address pointer.  
Read-only register. Continuously reflects the current address that DMA channel 1 is  
transferring from or will use in the next transfer. Base address register is transferred to  
this register whenever the LCD is enabled (LEN= 0 1) and when the current address is  
equal to the calculated end address of the buffer.  
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Peripheral Control Module  
11.7.10 DMA Channel 2 Base and Current Address Registers  
DMA channel 2’s base and current address registers (DBAR2 and DCAR2) function exactly like  
DMA channel 1’s except that they are used exclusively for dual-panel operation. (See the preceding  
sections.) When SDS=1, DMA channel 2 is used to supply frame buffer data to the lower half of the  
display. Note that the palette buffer, which resides within the first 16 or 256 entries of the frame buffer,  
is utilized only by DMA channel 1. The user should not place palette entries into the frame buffer for  
DMA channel 2. The base address for channel 2 points to the first encoded pixel values for the lower  
half of the display. For dual-panel operation, the user must perform the following sequence in order:  
disable the LCD (LEN=0), program dual-panel mode (SDS= 0 1), write the upper panel DMA base  
address, write the lower DMA base address and enable the LCD (LEN= 0 1). The following figures  
show the format of these registers; question marks indicate that the values are unknown at reset.  
Address: 0h B010 0018  
DBAR2: DMA Channel 2 Base Address Register  
Read/Write  
Bit  
Reset  
Bit  
31  
30  
29  
?
28  
?
27  
26  
25  
24  
23  
22  
21  
20  
?
19  
?
18  
17  
16  
?
DMA Channel 2 Base Address Pointer  
?
?
?
?
?
9
?
?
?
?
?
?
15  
?
14  
?
13  
?
12  
?
11  
?
10  
?
8
7
6
5
4
3
2
1
0
DMA Channel 2 Base Address Pointer  
Reset  
?
?
?
?
?
?
?
?
?
?
Bit  
Name  
DBAR2  
Description  
31..0  
DMA channel 2 base address pointer.  
Used to specify the base address of the frame buffer within off-chip memory for the lower  
half of the display in dual-panel operation. Value in DBAR2 is transferred to current  
address pointer register 2 when LCD is first enabled (LEN= 0 1) and when the current  
address pointer value reaches the end-of-frame buffer. DBAR2 should be written only  
when the LCD is disabled or immediately after an interrupt is generated by setting the  
base address update status (BAU) bit. The base address must be on a quadword  
boundary. The user must always write bits 0 through 3 to zero.  
Address: 0h B010 001C  
DCAR2: DMA Channel 2 Current Address Register  
Read-Only  
Bit  
Reset  
Bit  
31  
30  
29  
28  
?
27  
?
26  
25  
24  
23  
22  
21  
20  
?
19  
?
18  
?
17  
16  
?
DMA Channel 2 Current Address Pointer  
?
?
?
?
?
9
?
8
?
7
?
6
?
?
1
?
15  
?
14  
?
13  
?
12  
?
11  
?
10  
?
5
4
3
2
0
DMA Channel 2 Current Address Pointer  
Reset  
?
?
?
?
?
?
?
?
?
Bit  
Name  
Description  
DMA channel 2 current address pointer.  
Read-only register. Continuously reflects the current address that DMA channel 2 is  
31..0  
DCAR2  
transferring from or will use in the next transfer. Base address register is transferred to  
this register whenever the LCD is first enabled and when the current address is equal to  
the calculated end address of the buffer.  
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Peripheral Control Module  
11.7.11 LCD Controller Status Register  
The LCD controller status register (LCSR) contains bits that signal overrun and underrun errors for  
both the input and output FIFOs, ac bias pin transition count, LCD disabled, DMA base update  
ready, and DMA transfer bus error conditions. Each of these hardware-detected events signal an  
interrupt request to the interrupt controller.  
Each of the LCD’s status bits signal an interrupt request as long as the bit is set. Once the bit is  
cleared, the interrupt is cleared. Read/write bits are called status bits (read-only bits are called  
flags). Status bits are referred to as “sticky” (once set by hardware, they must be cleared by  
software). Writing a one to a sticky status bit clears it; writing a zero has no effect. Read-only flags  
are set and cleared by hardware; writes have no effect. The user has the ability to mask all LCD  
interrupts by clearing bit 12 within the interrupt controller mask register (ICMR). See the  
11.7.11.1 LCD Disable Done Flag (LDD) (read/write, maskable interrupt)  
The LCD disable done flag (LDD) is set after the LCD has been disabled and the frame that is  
active finishes being output to the LCD’s data pins. When the LCD is disabled by clearing the LCD  
enable bit (LEN= 0 1) in LCCR0, the LCD allows the current frame to complete before it is  
disabled. After the last set of pixels is clocked out onto the LCD’s data pins by the pixel clock, the  
LCD is disabled, LDD is set, and an interrupt request is made to the interrupt controller if it is  
unmasked (LDM=0). This interrupt is useful to allow an orderly shutdown of the LCD controller  
before the user places the SA-1100 into sleep mode.  
11.7.11.2 Base Address Update Flag (BAU) (read-only, maskable interrupt)  
The base address update flag (BAU) is a read-only bit that is set after the contents of the DMA base  
address register 1 are transferred to the DMA current address register 1 and is cleared when DMA  
base address register 1 is written. The value in the base address register is transferred to the current  
address register when the LCD is first enabled by writing a one to LEN (LEN= 0 1) and when the  
current address pointer equals the end address value calculated by the LCD controller. When BAU  
is set, an interrupt request is made to the interrupt controller if it is unmasked (BAM = 0). This  
interrupt allows the user to program the DMA with a new base address value to alternate between  
two or more frame buffer locations. When dual-panel mode is enabled (SDS=1), both DMA  
channels are enabled, and BAU is set only after both channels’ base address registers are  
transferred to their corresponding current address registers (1 and 2) and is cleared when DMA  
base address register 2 (lower panel) is written. Therefore, the user must always update the DMA  
base address register 1 (upper panel) first in dual-panel mode.  
11.7.11.3 Bus Error Status (BER) (read/write, maskable interrupt)  
The bus error status (BER) bit is set when a DMA transfer causes a bus error to occur on the ARM  
system bus. A bus error is signalled when the DMA controller attempts to access a reserved or  
nonexistent memory space. When this occurs, the SA-1100’s memory controller returns zeros for  
the read. It asserts the bus error signal to the LCD’s DMA, which in turn, causes the BER bit to be  
set and an interrupt request is made to the interrupt controller if it is unmasked (ERM = 0). The  
DMA is not disabled as a result of the bus error and operation continues as normal. If a DMA  
access causes a bus error, zeros are returned by the memory controller, which causes a palette entry  
to be filled with zeros (highest intensity color or black), or if pixel data is being DMAed, the LCD  
accesses the first location of the palette RAM one or more times.  
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Peripheral Control Module  
11.7.11.4 AC Bias Count Status (ABC) (read/write, nonmaskable interrupt)  
The ac bias count status (ABC) bit it set each time the ac bias pin (L_BIAS) transitions a particular  
number of times as specified by the ac bias pin transitions per interrupt (API) field in LCCR3. If  
API is programmed with a nonzero value, a counter is loaded with the value in API and is  
decremented each time the L_BIAS pin reverses state. When the counter reaches zero, the ABC bit  
is set, which signals an interrupt request to the interrupt controller. The counter reloads using the  
value in API, but does not start to decrement again until ABC is cleared by the user.  
11.7.11.5 Input FIFO Overrun Lower Panel Status (IOL) (read/write, maskable  
interrupt)  
The input FIFO overrun lower panel status (IOL) bit is set when the LCD’s DMA channel 2  
attempts to place data into the lower panel’s input FIFO after it has been completely filled. It is  
cleared by writing a one to the bit. This bit is used only in dual-panel mode (SDS=1). When this bit  
is set, an interrupt request is made to the interrupt controller if it is unmasked (ERM=0).  
11.7.11.6 Input FIFO Underrun Lower Panel Status (IUL) (read/write, maskable  
interrupt)  
The input FIFO underrun lower panel status (IUL) bit is set when the lower panel’s input FIFO is  
completely empty and the LCD’s pixel unpacking logic attempts to fetch data from the FIFO. It is  
cleared by writing a one to the bit. This bit is used only in dual-panel mode (SDS=1). When this bit  
is set, an interrupt request is made to the interrupt controller if it is unmasked (ERM=0).  
11.7.11.7 Input FIFO Overrun Upper Panel Status (IOU) (read/write, maskable  
interrupt)  
The input FIFO overrun upper panel status (IOU) bit is set when the LCD’s DMA channel 1  
attempts to place data into the upper panel’s input FIFO after it has been completely filled. It is  
cleared by writing a one to the bit. This bit is used in single-panel mode (SDS=0) and dual-panel  
mode (SDS=1). When this bit is set, an interrupt request is made to the interrupt controller if it is  
unmasked (ERM=0).  
11.7.11.8 Input FIFO Underrun Upper Panel Status (IUU) (read/write, maskable  
interrupt)  
The input FIFO underrun upper panel status (IUU) bit is set when the upper panel’s input FIFO is  
completely empty and the LCD’s pixel unpacking logic attempts to fetch data from the FIFO. It is  
cleared by writing a one to the bit. This bit is used in single-panel mode (SDS=0) and dual-panel  
mode (SDS=1). When this bit is set, an interrupt request is made to the interrupt controller if it is  
unmasked (ERM=0).  
11.7.11.9 Output FIFO Overrun Lower Panel Status (OOL) (read/write, maskable  
interrupt)  
The output FIFO overrun lower panel status (OOL) bit is set when the LCD’s dither logic attempts  
to place data into the lower panel’s output FIFO after it has been completely filled. It is cleared by  
writing a one to the bit. This bit is used only in dual-panel mode (SDS=1). When this bit is set, an  
interrupt request is made to the interrupt controller if it is unmasked (ERM = 0).  
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Peripheral Control Module  
11.7.11.10 Output FIFO Underrun Lower Panel Status (OUL) (read/write,  
maskable interrupt)  
The output FIFO underrun lower panel status (OUL) bit is set when the lower panel’s output FIFO  
is completely empty and the LCD’s data pin driver logic attempts to fetch data from the FIFO. It is  
cleared by writing a one to the bit. This bit is used only in dual-panel mode (SDS=1). When this bit  
is set, an interrupt request is made to the interrupt controller if it is unmasked (ERM=0).  
11.7.11.11 Output FIFO Overrun Upper Panel Status (OOU) (read/write,  
maskable interrupt)  
The output FIFO overrun upper panel status (OOU) bit is set when the LCD’s dither logic attempts  
to place data into the upper panel’s output FIFO after it has been completely filled. It is cleared by  
writing a one to the bit. This bit is used in single-panel mode (SDS=0) and dual-panel mode  
(SDS=1). When this bit is set, an interrupt request is made to the interrupt controller if it is  
unmasked (ERM=0).  
11.7.11.12 Output FIFO Underrun Upper Panel Status (OUU) (read/write,  
maskable interrupt)  
The output FIFO underrun upper panel status (OUU) bit is set when the upper panel’s output FIFO  
is completely empty and the LCD’s data pin driver logic attempts to fetch data from the FIFO. It is  
cleared by writing a one to the bit. This bit is used in single-panel mode (SDS=0) and dual-panel  
mode (SDS=1). When this bit is set, an interrupt request is made to the interrupt controller if it is  
unmasked (ERM=0).  
The following table shows the location of the status and flag bits in LCSR. For reserved bits, writes  
are ignored and reads return zero. Set status bits should be cleared by software before enabling  
both the LCD controller and interrupt controller.  
Read/Write &  
Address: 0h B010 0004  
LCSR: LCD Status Register  
Read-Only  
Bit  
Reset  
Bit  
31  
30  
29  
28  
0
27  
0
26  
0
25  
24  
23  
22  
21  
0
20  
0
19  
0
18  
0
17  
16  
0
Reserved  
0
0
0
0
0
0
0
0
15  
0
14  
13  
0
12  
0
11  
OUU  
0
10  
OOU  
0
9
OUL  
0
8
OOL  
0
7
IUU  
0
6
IOU  
0
5
IUL  
0
4
IOL  
0
3
ABC  
0
2
BER  
0
1
BAU  
0
0
LFD  
1
Reserved  
Reset  
0
Bit  
Name  
Description  
0
LDD  
LCD disable done flag.  
0 – LCD has not been disabled and the last active frame completed.  
1 – LCD has been disabled and the last active frame has just completed.  
1
BAU  
Base address update flag (read-only).  
0 – Base address has been written and has not yet been transferred to the current  
address register.  
1 – Base address has been transferred to the current address register, triggered either  
by enabling the LCD or when the current address pointer equals the end address value  
calculated by the LCD.  
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Peripheral Control Module  
Bit  
Name  
BER  
Description  
2
Bus error status.  
0 – DMA has not attempted an access to reserved/nonexistent memory space.  
1 – DMA has attempted an access to a reserved/nonexistent location in external  
memory. The errant DMA read returns zeros.  
3
ABC  
AC bias count status.  
0 – AC bias transition counter has not decremented to zero, or API is programmed to all  
zeros.  
1 – AC bias transition counter has decremented to zero, indicating that the L_BIAS pin  
has transitioned the number of times specified by the API control bit field. Counter is  
reloaded with the value in API but is disabled until the user clears ABC.  
4
5
IOL  
IUL  
Input FIFO overrun lower panel status.  
0 – Input FIFO for the lower panel display has not overrun.  
1 – DMA attempted to place data into the input FIFO for the lower panel after it has been  
filled.  
Input FIFO underrun lower panel status.  
0 – Input FIFO for the lower panel display has not underrun.  
1 – DMA not supplying data to input FIFO for the lower panel at a sufficient rate. FIFO  
has completely emptied; pixel unpacking logic has attempted to take added data from  
the FIFO.  
6
7
IOU  
IUU  
Input FIFO overrun upper panel status.  
0 - Input FIFO for the upper or whole panel display has not overrun.  
1 - DMA attempted to place data into the input FIFO for the upper or whole panel after it  
has been filled.  
Input FIFO underrun upper panel status.  
0 – Input FIFO for the upper or whole panel display has not underrun.  
1 – DMA not supplying data to input FIFO for the upper or whole panel at a sufficient  
rate. FIFO has completely emptied; pixel unpacking logic has attempted to take added  
data from the FIFO.  
8
9
OOL  
OUL  
Output FIFO overrun lower panel status.  
0 – Output FIFO for the lower panel display has not overrun.  
1 – Dither logic attempted to place data into the output FIFO for the lower panel after it  
had been filled.  
Output FIFO underrun lower panel status.  
0 – Output FIFO for the lower panel display has not underrun.  
1 – LCD dither logic not supplying data to output FIFO for the lower panel at a sufficient  
rate. FIFO has completely emptied and data pin driver logic has attempted to take  
added data from the FIFO.  
10  
11  
OOU  
OUU  
Output FIFO overrun upper panel status.  
0 – Output FIFO for the upper or whole panel display has not overrun.  
1 – Dither logic attempted to place data into the output FIFO for the upper or whole  
panel after it had been filled.  
Output FIFO underrun upper panel status.  
0 – Output FIFO for the upper or whole panel display has not underrun.  
1 – LCD dither logic not supplying data to output FIFO for the upper or whole panel at a  
sufficient rate. FIFO has completely emptied and data pin driver logic has attempted to  
take added data from the FIFO.  
31..12  
Reserved.  
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Peripheral Control Module  
11.7.12 LCD Controller Register Locations  
Table 11-9 shows the registers associated with the LCD controller and the physical addresses used  
to access them.  
Figure 11-34 to Figure 11-38 describe the LCD controller timing parameters.  
Table 11-9. LCD Controller Control, DMA, and Status Register Locations  
Address  
0hB010 0000  
Name  
LCCR0  
Description  
LCD controller control register 0  
LCD controller status register 1  
Reserved  
0hB010 0004  
LCSR  
0hB010 0008 – 0h B010 000C  
0hB010 0010  
DBAR1  
DCAR1  
DBAR2  
DCAR2  
LCCR1  
LCCR2  
LCCR3  
DMA channel 1 base address register  
DMA channel 1 current address register  
DMA channel 2 base address register  
DMA channel 2 current address register  
LCD controller control register 1  
LCD controller control register 2  
LCD controller control register 3  
Reserved  
0hB010 0014  
0hB010 0018  
0hB010 001C  
0hB010 0020  
0hB010 0024  
0hB010 0028  
0hB010 002C – 0hB010 FFFF  
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11.7.13 LCD Controller Pin Timing Diagrams  
Figure 11-10. Passive Mode Beginning-of-Frame Timing  
VSP = 0  
L_FCLK  
L_LCLK  
LEN set to 1  
HSP = 0  
L_PCLK  
VSW = 1  
ELW = 2  
HSW = 6  
BLW = 2  
LDD[x:0]  
Line 0 Data  
PPL = 16  
Line 1 Data  
Line 2 Data  
Notes:  
LEN - LCD enable:  
0 - LCD is disabled.  
1 - LCD is enabled.  
VSP - Vertical sync polarity:  
0 - Frame clock is active high, inactive low.  
1 - Frame clock is active low, inactive high.  
VSW - Vertical Sync Pulse Width:  
1 to 64 horizontal sync clock periods to assert the vertical sync signal (hsync transitions).  
HSP - Horizontal sync polarity:  
0 - Line clock is active high, inactive low.  
1 - Line clock is active low, inactive high.  
ELW - End-of-line pixel clock wait count:  
1 to 256 "dummy" pixel clock periods to wait after last pixel in line before asserting line clock  
(pixel clock does not transition).  
BLW - Beginning-of-line pixel clock wait count:  
1 to 256 "dummy" pixel clock periods to wait after line clock negated before asserting pixel clocks  
(pixel clock does not transition).  
HSW - Horizontal sync pulse width:  
0 to 64 "dummy" pixel clock periods to assert the line clock (pixel clock does not transition).  
PPL - Pixels per line:  
16 to 1024 pixels per line on the screen (must be programmed on 16 pixel multiples).  
Frame clock asserted on first pixel clock of each frame, and is negated one "dummy" pixel clock  
period before the first pixel clock of the 2nd line.  
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Figure 11-11. Passive Mode End-of-Frame Timing  
L_FCLK  
L_LCLK  
L_PCLK  
ELW = 1  
VSW = 2  
BLW = 1  
LDD[x:0]  
Line 479 Data  
LPP = 480  
Line 0 Data  
Notes:  
BLW - Beginning-of-line pixel clock wait count:  
0 to 256 "dummy" pixel clock periods to wait after line clock is negated before asserting pixel  
clocks (pixel clock does not transition).  
VSW - Vertical sync pulse width:  
In passive mode, 1 to 64 line clock periods to wait between the end of one frame and the  
beginning of the next frame (line clock transitions).  
ELW - End-of-line pixel clock wait count:  
1 to 256 "dummy" pixel clock periods to wait after last pixel in line before asserting line clock  
(pixel clock does not transition).  
LPP - Lines per panel:  
1 to 1024 lines per panel.  
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Figure 11-12. Passive Mode Pixel Clock and Data Pin Timing  
L_FCLK  
L_LCLK  
PCP = 0  
L_PCLK  
Data Pins Sampled  
by the Display  
Data Pins Change  
Pixels 8 through 11 Pixels 12 through 15  
LDD[3:0]*  
*DPD = 0  
Pixels 0 through 3  
Pixels 4 through 7  
Notes:  
PCP - Pixel clock polarity:  
0 - Pixels sampled from data pins on rising edge of pixel clock.  
1 - Pixels sampled from data pins on falling edge of pixel clock.  
DPD - Dual pixel data mode:  
0 - 4 data pins are used in single-panel monochrome mode.  
1 - 8 data pins are used in single-panel monochrome mode.  
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Figure 11-13. Active Mode Timing  
VSP = 0  
VSW = 0  
LEN set to 1  
L_FCLK  
(VSYNC)  
HSW = 4  
HSP = 0  
L_LCLK  
(HSYNC)  
L_BIAS  
(OE)  
L_PCLK  
BFW = 1  
BFW = 2  
ELW = 1  
BLW = 1  
LDD[7:0],  
GPIO[9:2]  
Line 0 Data  
PPL = 16  
Line 1 Data  
Notes:  
LEN - LCD enable:  
0 - LCD is disabled.  
1 - LCD is enabled.  
VSP - Vertical sync polarity:  
0 - Vertical sync clock is active high, inactive low.  
1 - Vertical sync clock is active low, inactive high.  
VSW - Vertical sync width:  
1 to 64 horizontal sync clock periods to assert the vertical sync signal (hsync transitions).  
HSW - Horizontal sync pulse width:  
1 to 64 pixel clock periods to assert the line clock (pixel clock transitions).  
HSP - Horizontal sync polarity:  
0 - Horizontal sync clock is active high, inactive low.  
1 - Horizontal sync clock is active low, inactive high.  
BFW - Beginning-of-frame horizontal sync clock wait count:  
0 to 255 horizontal sync clock periods to wait at the beginning of each frame (hsync transitions).  
BLW - Beginning-of-line pixel clock wait count:  
1 to 256 pixel clock periods to wait after line clock negated before asserting pixel clocks  
(pixel clock transitions).  
ELW - End-of-line pixel clock wait count:  
1 to 256 pixel clock periods to wait after last pixel in line before asserting line clock (pixel clock  
transitions).  
PPL - Pixels per line:  
1 to 1024 pixels per line on screen.  
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Figure 11-14. Active Mode Pixel Clock and Data Pin Timing  
L_FCLK  
(VSYNC)  
L_BIAS  
OE)  
L_LCLK  
(HSYNC)  
PCP = 0  
L_PCLK  
Data Pins Sampled  
by the Display  
Data Pins Change  
LDD[7:0],  
GPIO[9:2]  
Pixels 0 through 15  
Pixels 16 through 31 Pixels 32 through 47  
Pixels 48 through 63  
Notes:  
PCP - Pixel clock polarity:  
0 - Pixels sampled from data pins on rising edge of pixel clock.  
1 - Pixels sampled from data pins on falling edge of pixel clock.  
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11.8  
Serial Port 0 – USB Device Controller  
This section describes the implementation-specific options of the USB protocol for a device  
controller as it applies to serial port 0, such as number, type, and function of the endpoints,  
interrupts to the CPU, transmit/receive FIFO interface, and so on. It is assumed that the user has a  
working knowledge of the USB standard. The UDC is USB-compliant and supports all standard  
device requests issued by the host. For programmer convenience, summaries of UDC operation are  
provided as well as quick reference tables. However, the user should refer to the Universal Serial  
Bus Specification, Revision 1.01 for a full description of the USB protocol and its operation.  
Serial port 0 is a universal serial bus device controller (UDC) that supports three endpoints and can  
operate half-duplex at a baud rate of 12 Mbps (slave only, not a host or hub controller).  
The serial information transmitted by the UDC contains layers of communication protocols, the most  
basic of which are fields. UDC fields include: sync, packet identifier, address, endpoint, frame number,  
data, and CRC fields. Fields are used to produce packets. Depending on the function of a packet, a  
different combination and number of fields are used. Packet types include: token, start of frame, data,  
and handshake packets. Packets are then assembled into groups to produce frames. These frames or  
transactions fall into four groups: bulk, control, interrupt, and isochronous. (The UDC supports only  
bulk and control.) Endpoint 0, by default, is used only to communicate control transactions to configure  
the UDC after it is reset or hooked up (physically connected to an active USB host or hub). Endpoint 0’s  
responsibilities include: connection, address assignment, endpoint configuration, bus enumeration, and  
disconnect. Endpoint 1 is used to perform bulk OUT data transactions and receiving data from the USB  
host; endpoint 2 is used to perform bulk IN data transactions and transmitting data to the USB host.  
The UDC uses two separate FIFOs to buffer incoming and outgoing data to or from the host  
(16-entry x 8-bit for transmitting, and 20-entry x 8-bit for receiving). The FIFOs can be filled or  
emptied either by the DMA or the CPU, with service requests being signalled when either FIFO is  
half-full or empty. Interrupts are signalled when the receive FIFO experiences an overrun and the  
transmit FIFO experiences an underrun. The control endpoint 0 has an additional 8-entry x 8-bit  
FIFO that can only be read or written by processor reads and writes.  
The external pins dedicated to this interface are UDC+ and UDC-. The USB protocol uses  
differential signalling between the two pins for half-duplex data transmission. A 1.5-Kohm pull-up  
resistor is required to be connected to the USB cable’s D+ signal to pull the UDC+ pin high when  
not driven. This signifies the UDC is a high-speed, 12-Mbps device and provides the correct  
polarity for data transmission. Using differential signalling allows multiple states to be transmitted  
on the serial bus. These states are combined to transmit data as well as various bus conditions,  
including: idle, resume, start of packet, end of packet, disconnect, connect, and reset.  
11.8.1  
USB Operation  
Following a reset of the SA-1100 or whenever the UDC is attached to a USB bus, all endpoints are  
automatically configured by the UDC and the UDC is forced to use the USB default address of  
zero. The host then assigns the UDC a unique address. At this point, the UDC is under the host’s  
control and responds to its commands that are transmitted to endpoint 0 using control transactions.  
Endpoint 1 is used to perform bulk OUT data transactions, receiving data from the USB host, and  
endpoint 2 bulk IN data transactions, transmitting data to the USB host.  
The following sections provide details of the USB protocol in a bottom-up fashion starting with  
signalling levels.  
1. The latest revision of the Universal Serial Bus Specification Revision 1.0 can be accessed via the World Wide Web Internet site at:  
http://www.teleport.com/~usb/  
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11.8.1.1  
Signalling Levels  
USB uses differential signalling to encode data and to communicate various bus conditions. The  
USB specification refers to the J and K data states to differentiate between high- and low-speed  
transmission. Because the UDC supports only 12-Mbps transmission, references are made only to  
actual data state 0 and actual data state 1.  
Four distinct states are represented using differential data by decoding the polarity of the UDC+  
and UDC- pins. Two of the four states are used to represent data. A one is represented when UDC+  
is high and UDC- is low; a zero is represented when UDC+ is low and UDC- is high. The  
remaining two states and pairings of the four encodings are further decoded to represent the current  
state of the USB bus. Table 11-10 shows how seven different bus states are represented using  
differential signalling.  
Table 11-10. USB Bus States  
Bus State  
UDC+/UDC- Pin Levels  
UDC+ high, UDC- low (same as a 1).  
Idle  
Resume  
UDC+ low, UDC- high (same as a 0).  
Start of Packet  
End of Packet  
Disconnect  
Transition from idle to resume.  
UDC+ AND UDC- low for 2-bit times followed by an idle for 1-bit time.  
UDC+ AND UDC- below single-ended low threshold for more than 2.5 µs.  
(Disconnect is the static bus condition that results when no device is plugged into a hub  
port.)  
Connect  
Reset  
UDC+ OR UDC- high for more than 2.5 µs.  
UDC+ AND UDC- low for more than 2.5 µs. (Reset is driven by the host controller and  
sensed by a device controller.)  
Hosts and hubs have pull-down resistors on both the D+ and D- lines. When a device is not attached  
to the cable, the pull-down resistors cause D+ and D- to be pulled down below the single-ended low  
threshold of the host or hub. This creates a state called single-ended zero (SE0). A disconnect is  
detected by the host when an SE0 persists for more than 2.5 µs (30-bit times). When the UDC is  
connected to the USB cable, the pull-up resistor on the UDC+ pin causes D+ to be pulled above the  
single-ended high threshold level. After 2.5 µs elapse, the host detects a connect.  
After this point, the bus is in the idle state because UDC+ is high and UDC- is low. A start of  
packet is signalled by transitioning the bus from the idle to the resume state (a 1 to 0 transition).  
The beginning of each USB packet begins with a sync field, which starts with the 1-to-0 transition  
(see the Section 11.8.1.1, “Signalling Levels” on page 11-57). After the packet data has been  
transferred, an end of packet is signalled by pulling both UDC+ and UDC- low for 2-bit times,  
followed by an idle for 1-bit time. If the idle persists for more than 3 ms, the UDC enters suspend  
mode and it is placed in low-power mode. The UDC can be awakened from the suspend state by  
the host by switching the bus to the resume state via normal bus activity, or by signalling a reset.  
Under normal operating conditions, the host ensures that devices do not enter the suspend state by  
periodically signalling an end of packet (EOP).  
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11.8.1.2  
Bit Encoding  
USB uses nonreturn to zero inverted (NRZI) to encode individual bits. Both the clock and the data  
are encoded and transmitted within the same signal. Instead of representing data by controlling the  
state of the signal, transitions are used. A zero is represented by a transition, and a one is  
represented by no transition (this produces the data). Each time a zero occurs, the receiver logic  
synchronized the baud clock to the incoming data (this produces the clock). To ensure the receiver  
is periodically synchronized, any time six consecutive ones are detected in the serial bit stream, a  
zero is automatically inserted by the transmitter. This procedure is known as “bit stuffing”. The  
receiver logic, in turn, automatically detects stuffed bits and removes them from the incoming data.  
Bit stuffing causes a transition on the incoming signal at least once every seven bit-times to  
guarantee baud clock lock. Bit stuffing is enabled for an entire packet beginning when the start of  
packet is detected until the end of packet is detected (enabled during the sync field all the way  
through the CRC field). Figure 11-15 shows the NRZI encoding of the data byte 0b1101 0010.  
Figure 11-15. NRZI Bit Encoding Example  
Bit  
Value  
1
1
0
1
0
0
1
0
Digital  
Data  
NRZI  
Data  
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11.8.1.3  
Field Formats  
Individual bits are assembled into groups called fields. Fields are used to construct packets and  
packets are used to construct frames or transactions. The seven USB field types include: sync,  
packet identifier, address, endpoint, frame number, data, and CRC fields.  
A sync is preceded by the idle state on the USB bus and is always the first field of every packet.  
The first bit of a sync field signals the start of packet (SOP) to the UDC or host. A sync is 8 bits  
wide and consists of seven zeros followed by a one (0x80).  
The packet identifier (PID) is 1 byte wide and always follows the sync field. The first 4 bits contain  
an encoded value that represents packet type (token, data, handshake, special), packet format, and  
type of error detection. The last four bits contain a check field that ensures the PID is transmitted  
without errors. The check field is generated by performing a ones complement of the PID. The UDC  
automatically XORs the PID and check field and takes the appropriate action (as prescribed by the  
USB standard) if the result does not contain all ones, indicating an error has occurred in transmission.  
The UDC’s three endpoints are accessed using the address and endpoint fields. The address field  
contains 7 bits and permits 128 unique devices to be placed on the USB. After the SA-1100 is reset,  
or a reset is signalled via the USB bus, the UDC (and all other 127 possible devices) is assigned the  
default address of zero. The host is then responsible for assigning unique addresses for each device  
on the bus. This is performed in the enumeration process one device at a time. Once the host  
assigns the UDC an address, it responds only to transactions addressed to it. The address field is  
transmitted in every packet and follows the PID field.  
When the UDC detects that a packet is addressed to it, the endpoint field is used to determine  
which of the UDC’s three endpoints are being addressed. The endpoint field is 4 bits. However,  
only the encodings for endpoints 0 through 2 are allowed. The endpoint field follows the address  
field. Table 11-11 shows the valid values for the endpoint field.  
.
Table 11-11. Endpoint Field Addressing  
Endpoint Field Value  
UDC Endpoint Selected  
0000  
0001  
0010  
0011  
01xx  
10xx  
11xx  
Endpoint 0  
Endpoint 1  
Endpoint 2  
Invalid  
Invalid  
Invalid  
Invalid  
The frame number is an 11-bit field that is incremented by the host each time a frame is  
transmitted. When it reaches its maximum value of 2047 (0x7FF), it rolls over. It is transmitted in  
the start of frame (SOF) packet, which is output by the host in 1 ms intervals. The frame number  
field is used only by device controllers to control isochronous transfers, and therefore, does not  
affect the UDC. Data fields are used to transmit the bulk data between the host and the UDC. A  
data field is made up of 0 to 1023 bytes. Each byte is transmitted LSB first.  
Cyclic redundancy check fields are used to detect errors introduced during transmission of token  
and data packets, and is applied to all the fields in the packet except the PID field (recall the PID  
contains its own 4-bit ones complement check field for error detection). Token packets use a 5-bit  
CRC (x5+x2+1) and data packets use a 16-bit CRC (x16+x15+x2+1). For both CRCs, the checker is  
reset to all ones at the start of each packet.  
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11.8.1.4  
Packet Formats  
USB supports four packet types: token, data, handshake, and special. A token packet is placed at  
the beginning of a frame and is used to identify OUT, IN, SOF, and SETUP transactions. OUT and  
IN frames are used to transfer data, SOF packets are used to time isochronous transactions, and  
SETUP packets are used for control transfers to configure endpoints. A token packet consists of a  
sync, a PID, an address, an endpoint, and a CRC5 field (see Figure 11-16). For OUT and SETUP  
transactions, the address and endpoint fields are used to select which UDC endpoint is to receive  
the data, and for an IN transaction, which endpoint must transmit data.  
Figure 11-16. IN, OUT, and SETUP Token Packet Format  
8 bits  
Sync  
8 bits  
PID  
7 bits  
4 bits  
5 bits  
Address  
Endpoint  
CRC5  
A start of frame (SOP) is a special type of token packet that is issued by the host once every 1 ms.  
SOF packets consist of a sync, a PID, a frame number (which is incremented after each frame is  
transmitted), and a CRC5 field, as shown in Figure 11-17. Even though the UDC on the SA-1100  
does not make use of the frame number field, the presence of SOF packets every 1ms will prevent  
the UDC from going into suspend mode.  
Figure 11-17. SOF Token Packet Format  
8 bits  
Sync  
8 bits  
PID  
11 bits  
5 bits  
Frame Number  
CRC5  
Data packets follow token packets, and are used to transmit data between the host and UDC. There  
are two types of data packets as specified by the PID: DATA0 and DATA1. These two types are  
used to provide a mechanism to guarantee data sequence synchronization between the transmitter  
and receiver across multiple transactions. During the handshake phase, both communicate and  
agree which data token type to transmit first. For each subsequent packet transmitted, the data  
packet type is toggled ( DATA0, DATA1, DATA0, and so on). A data packet consists of a sync, a  
PID, from 0 to 1023 bytes of data, and a CRC16 field, as shown in Figure 11-18.  
Figure 11-18. Data Packet Format  
8 bits  
Sync  
8 bits  
PID  
0–1023 bytes  
Data  
16 bits  
CRC16  
Handshake packets consist of only a sync and a PID. Handshake packets do not contain a CRC  
because the PID contains its own check field. They are used to report data transaction status,  
including whether data was successfully received, flow control, and stall conditions. Only  
transactions that support flow control can return handshakes. The three types of handshake packets  
are: ACK, NAK, and STALL. ACK indicates that a data packet was received without bit stuffing,  
CRC, or PID check errors. NAK indicates that the UDC was unable to accept data from the host or  
it has no data to transmit. NAK is also used by endpoint 1 to indicate no interrupts are pending.  
STALL indicates that the UDC is unable to transmit or receive data, and requires host intervention  
to clear the stall condition. Bit stuffing, CRC, and PID errors are signalled by the receiving unit by  
omitting a handshake packet. Figure 11-19 shows the format of a handshake packet.  
Figure 11-19. Handshake Packet Format  
8 bits  
Sync  
8 bits  
PID  
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11.8.1.5  
Transaction Formats  
Packets are assembled into groups to form transactions. Four different transaction formats are used  
in the USB protocol. Each is specific to a particular endpoint type: bulk, control, interrupt, and  
isochronous. Note that isochronous and interrupt transactions are not supported by the UDC and  
are not described in this section. Endpoint 0, by default, is a control endpoint and receives only  
control transactions; both endpoints 1 and 2 use bulk transactions. Note that all USB bus  
transactions are initiated by the host controller and that transmission takes place between the host  
and UDC one direction at a time (half-duplex).  
Bulk transactions guarantee error-free transmission of data between the host and UDC by using  
packet error detection and retry. The three packet types used to construct bulk transactions are:  
token, data, and handshake. The eight possible types of bulk transactions based on data direction,  
error, and stall conditions are shown in Figure 11-20. Note that packets sent by the UDC to the  
host are highlighted in boldface type, and packets sent by the host to the UDC are not.  
Figure 11-20. Bulk Transaction Formats  
Action  
Token Packet  
Data Packet  
Handshake Packet  
ACK  
Host successfully received data from UDC  
IN  
DATA0/DATA1  
UDC temporarily unable to transmit data  
UDC endpoint needs host intervention  
Host detected PID, CRC, or bit stuff error  
UDC successfully received data from host  
UDC temporarily unable to receive data  
UDC endpoint needs host intervention  
UDC detected PID, CRC, or bit stuff error  
IN  
None  
NAK  
STALL  
None  
ACK  
IN  
None  
IN  
DATA0/DATA1  
DATA0/DATA1  
DATA0/DATA1  
DATA0/DATA1  
DATA0/DATA1  
OUT  
OUT  
OUT  
OUT  
NAK  
STALL  
none  
Packets from UDC to host are boldface  
Control transactions are used by the host to configure endpoints and query their status. Like bulk  
transactions, control transactions begin with a setup packet, followed by an optional data packet,  
then a handshake packet. Note that control transactions, by default, use DATA0 type transfers.  
Figure 11-21 shows the four possible types of control transactions. Note that packets sent by the  
UDC to the host are highlighted in boldface type, and packets sent by the host to the UDC are not.  
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Figure 11-21. Control Transaction Formats  
Action  
Token Packet  
Data Packet  
Handshake Packet  
ACK  
UDC successfully received control from host  
SETUP  
DATA0  
UDC temporarily unable to receive data  
UDC endpoint needs host intervention  
UDC detected PID, CRC, or bit stuff error  
SETUP  
SETUP  
SETUP  
DATA0  
DATA0  
DATA0  
NAK  
STALL  
None  
Packets from UDC to host are boldface  
Control transfers are assembled by the host by first sending a control transaction to tell the UDC  
what type of control transfer is taking place (control read or control write), followed by two or  
more bulk data transactions. The control transaction, by default, uses a DATA0 transfer, and each  
subsequent bulk data transaction toggles between DATA1 and DATA0 transfers. For a control write  
to an endpoint, OUT transactions are used. For control reads, IN transactions are used. The transfer  
direction of the last bulk data transaction is reversed. It is used to report status and functions as a  
handshake. The last bulk data transaction always uses a DATA1 transfer by default (even if the  
previous bulk transaction used DATA1). For a control write, the last transaction is an IN from the  
UDC to the host, and for a control read, the last transaction is an OUT from the host to the UDC.  
11.8.1.6  
UDC Device Requests  
The UDC’s control, status, and data registers are used only to control and monitor the transmit and  
receive FIFOs for endpoints 1 and 2. All other UDC configuration and status reporting is controlled  
by the host via the USB bus using device requests that are sent as control transactions to endpoint  
0. Each setup packet to endpoint 0 is 8 bytes long and specifies:  
Data transfer direction: host to device, device to host  
Data transfer type: standard, class, vendor  
Data recipient: device, interface, endpoint, other  
Number of bytes to transfer  
Index or offset  
Value: used to pass a variable-sized data parameter  
Device request  
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Peripheral Control Module  
Table 11-12 shows a summary of all device requests. Users should refer to the Universal Serial Bus  
Specification Revision 1.0 for a full description of host device requests.  
Table 11-12. Host Device Request Summary  
Request  
Name  
SET_FEATURE  
Used to enable a specific feature such as device remote wake-up and  
endpoint stalls.  
CLEAR_FEATURE  
Used to clear or disable a specific feature.  
SET_CONFIGURATION  
Configures the UDC for operation. Used following a reset of the SA-1100 or  
after a reset has been signalled via the USB bus.  
GET_CONFIGURATION  
SET_DESCRIPTOR  
Returns the current UDC configuration to the host.  
Used to set existing descriptors or add new descriptors. Existing descriptors  
include: device, configuration, string, interface, and endpoint.  
GET_DESCRIPTOR  
SET_INTERFACE  
GET_INTERFACE  
GET_STATUS  
Returns the specified descriptor if it exists.  
Used to select an alternate setting for the UDC’s interface.  
Returns the selected alternate setting for the specified interface.  
Returns the UDC’s status including: remote wake-up, self-powered, data  
direction,  
endpoint number, and stall status.  
SET_ADDRESS  
SYNCH_FRAME  
Sets the UDC’s 7-bit address value for all future device accesses.  
Used to set and then report an endpoint’s synchronization frame.  
11.8.2  
UDC Register Definitions  
All configuration, request/service, and status reporting is controlled by the USB host controller and  
is communicated to the UDC via the USB bus. Several registers are available to the programmer to  
control the interfacing of the UDC to software. A control register is used to enable the UDC and to  
mask the various interrupt sources that exist within the UDC. A status register is used to indicate  
the state of the various interrupt sources. The device address register is available, which software  
writes when parsing a SET_ADDRESS command from the USB host controller. There is a register  
for each of the OUT and IN endpoints’ maximum packet size. All three endpoints (control, OUT,  
and IN) have a control/status register. Endpoint 0 (control) has an address for the 8 x 8 data FIFO  
used for both transmitting and receiving data, as well as a write count register used to determine  
how many bytes the USB host controller has sent to the endpoint 0. Both endpoints 1 and 2 (OUT  
and IN, respectively) share a data register address that contains an 8-bit field, which addresses the  
top of the transmit FIFO and bottom of the receive FIFO. When it is read, the receive FIFO is  
accessed, and when it is written, the transmit FIFO is accessed.  
Note: Due to the internal synchronization required by the UDC’s configuration registers, it is possible for  
the processor to write the UDC registers and FIFOs too fast. It is required that all writes to the UDC  
be complete before another write may take place. In order to guarantee that a write is complete, it is  
necessary to observe the effect of a write before another write may take place. For example, when  
writing a UDC register followed by an immediate read to verify data in the same register, the first  
read will be invalid and the second read will have correct data.  
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Peripheral Control Module  
11.8.3  
UDC Control Register  
The UDC control register (UDCR) contains seven control bits: two to enable or disable the UDC  
and five to mask the transmit and receive FIFO service requests.  
11.8.3.1  
UDC Disable (UDD)  
The UDC disable (UDD) bit is used to enable and disable the UDC. When UDD=0, the UDC is  
enabled for serial transmission or reception. When UDC=1, it is disabled and the UDC+ and UDC-  
pins are tristated.  
If UDD is written to one the entire UDC design is reset. If this is done while the UDC is actively  
transmitting or receiving data, it stops immediately and the remaining bits within the transmit or  
receive serial shifter are reset. In addition, all entries within the transmit and receive FIFO ar reset.  
11.8.3.2  
11.8.3.3  
UDC Active (UDA)  
This read-only bit can be read to determine if the UDC is currently active. A one indicates that the  
UDC is currently involved in a transaction.  
Bit 2 Reserved  
Bit 2 is reserved and should always be written to a zero to ensure compatibility with future  
revisions of this design. This bit also will be set if the UDC detects that the data toggle mechanism  
did not occur.  
11.8.3.4  
11.8.3.5  
11.8.3.6  
Endpoint 0 Interrupt Mask (EIM)  
The endpoint 0 interrupt mask (EIM) bit is used to mask or enable the endpoint 0 interrupt request.  
When EIM=1, the interrupt is masked and the EIR bit in the status/interrupt register is not allowed  
to be set. When EIM=0, the interrupt is enabled, and whenever an interruptible condition occurs in  
the receiver, the EIR bit is set. Note that programming EIM=1 does not affect the current state of  
EIR; it only blocks future zero to one transitions of EIR.  
Receive Interrupt Mask (RIM)  
The receive interrupt mask (RIM) bit is used to mask or enable the receive FIFO service request  
interrupt. When RIM=1, the interrupt is masked and the RIR bit in the status/interrupt register is  
not allowed to be set. When RIM=0, the interrupt is enabled, and whenever an interruptible  
condition occurs in the receiver, the RIR bit is set. Note that programming RIM=1 does not affect  
the current state of RIR; it only blocks future zero to one transitions of RIR.  
Transmit Interrupt Mask (TIM)  
The transmit interrupt mask (TIM) bit is used to mask or enable the transmit endpoint 2 interrupt  
request. When TIM=1, the interrupt is masked and the TIR bit in the status/interrupt register is not  
allowed to be set. When TIM=0, the interrupt is enabled, and whenever an interruptible condition  
occurs in the transmitter, the TIR bit is set. Note that programming TIM=1 does not affect the  
current state of TIR; it only blocks future zero to one transitions of TIR.  
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Peripheral Control Module  
11.8.3.7  
11.8.3.8  
Suspend/Resume Interrupt Mask (SRM)  
The suspend/resume interrupt mask (SRM) bit is used to mask or enable the suspend/resume  
interrupt request. When SRM=1, the interrupt is masked, and the SUSIR/RESIR bits in the  
status/interrupt register are not allowed to be set. When SRM=0, the interrupt is enabled, and  
whenever a suspend or resume condition occurs, the SUSIR or RESIR bit is set. Note that  
programming SRM=1 does not affect the current state of SUSIR/RESIR; it only blocks future zero  
to one transitions of SUSIR/RESIR.  
Reset Interrupt Mask (REM)  
The reset interrupt mask (REM) bit is used to mask or enable the reset interrupt request. When  
REM=1, the interrupt is masked, and the RSTIR bit in the status/interrupt register is not allowed to  
be set. When REM=0, the interrupt is enabled, and whenever the USB host controller issues a reset  
to the UDC, the RSTIR bit is set. Note that programming REM=1 does not affect the current state  
of RSTIR; it only blocks future zero to one transitions of RSTIR.  
The following table shows the location of the UDE, RIM, and TIM bits in UDC control register  
(UDCR). The state of RIM and TIM are unknown and must be initialized before enabling the  
UDC. The UDE bit is cleared to zero, disabling the UDC following a reset of the SA-1100. This  
gives control of the UDC’s pins to the PPC unit that configures them as inputs. Writes to reserved  
bits are ignored and reads return zeros.  
Address: 0h 8000 0000  
UDCCR  
Read/Write & Read Only  
Bit  
7
REM  
0
6
SRM  
1
5
TIM  
0
4
3
EIM  
0
2
Res.  
0
1
UDA  
0
0
UDD  
1
RIM  
0
Reset  
Bit  
Name  
Description  
0
UDD  
UDD disable.  
0 – UDD disabled.  
1 – UDD enabled, UDC+ and UDC- used for USB serial transmission/reception.  
1
UDA  
UDC active (read-only).  
0 – UDC currently inactive.  
1 – UDC currently active.  
2
3
Reserved.  
EIM  
Endpoint zero interrupt mask.  
0 – Endpoint zero interrupt enabled.  
1 – Endpoint zero interrupt disabled.  
4
5
6
7
RIM  
TIM  
Receive interrupt mask.  
0 – Receive interrupt enabled.  
1 – Receive interrupt disabled.  
Transmit interrupt mask.  
0 – Transmit interrupt enabled.  
1 – Transmit interrupt disabled.  
SRM  
REM  
Suspend/resume interrupt mask.  
0 – Suspend/resume interrupt enabled.  
1 – Suspend/resume interrupt disabled.  
Reset interrupt mask.  
0 – Reset interrupt enabled.  
1 – Reset interrupt disabled.  
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Peripheral Control Module  
11.8.4  
UDC Address Register  
The UDC address register contains a 7-bit field that holds the device address. After a reset of the  
UDC core, the value of this register is zero. The CPU writes an address to this register when it  
receives a SET_ADDRESS from the USB host controller. It extracts the address assigned to the  
UDC from the SET_ADDRESS command and writes the value into the UDC address register. The  
new address is not propagated to the rest of the UDC core until the SET_ADDRESS command is  
completed with an acknowledged handshake from the UDC.  
Address: 0h 8000 0004  
UDCAR  
Read/Write  
Bit  
7
Res  
0
6
5
4
3
2
1
0
0
7-bit Function Address  
Reset  
0
0
0
0
0
0
Bit  
Name  
Description  
7
Reserved.  
Always read zero.  
Function address field  
7-bit function address. Reset to all zero.  
6..0  
Address  
11.8.5  
UDC OUT Max Packet Register  
The UDC OUT max packet register holds the value of the maximum packet size the UDC core will  
accept minus one. This is done in order to accommodate maximum packets of 256 bytes, without  
going to a max packet field of more than 8 bits. In order to accept packets up to 256 bytes, a value  
of 0xff (255) should be written into the OUT max packet register. At reset the OUT max packet  
register contains 0x08, and will therefore accept packets of length 9 bits or less.  
Address: 0h 8000 0008  
UDCOMP  
Read/Write  
Bit  
7
6
5
0
4
3
2
0
1
0
0
Max Packet Size - 1  
Reset  
0
0
0
1
0
Bit  
Name  
Description  
7..0  
OUT  
MaxP  
OUT max packet size.  
8-bit field containing the value of the maximum packet size minus one.  
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Peripheral Control Module  
11.8.6  
UDC IN Max Packet Register  
The UDC IN max packet register holds the value of the number of bytes the UDC core is to  
transmit minus one. This is done in order to accommodate maximum packets of 256 bytes, without  
going to a max packet field of more than 8 bits. In order to transmit packets of 256 bytes, a value of  
0xff (255) should be written into the IN max packet register. At reset the IN max packet register  
contains 0x08, and will therefore transmit packets of length 9 bits.  
Address: 0h 8000 000C  
UDCIMP  
Read/Write  
Bit  
7
6
5
0
4
3
2
0
1
0
0
Max Packet Size - 1  
Reset  
0
0
0
1
0
Bit  
Name  
Description  
7..0  
IN MaxP  
IN max packet size.  
8-bit field containing the value of the number of bytes to transmit minus one.  
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Peripheral Control Module  
11.8.7  
UDC Endpoint 0 Control/Status Register  
The UDC endpoint zero control/status register contains 8 bits that are used to operate endpoint zero  
(control endpoint).  
11.8.7.1  
OUT Packet Ready (OPR)  
The OUT packet ready bit is set by the UDC when it receives a valid token to endpoint zero. When  
this bit is set, the EIR bit will be set in the UDC status/interrupt register if endpoint zero interrupts  
are enabled. This bit is cleared by writing a one to the serviced out packet ready bit (6). The UDC  
is not allowed to enter the data phase of a transaction until this bit is cleared. If there is no data  
phase, then the CPU should set the data end bit (4) at the same time it clears this bit.  
11.8.7.2  
11.8.7.3  
IN Packet Ready (IPR)  
The IN packet ready bit is set by the CPU after it has written a packet to the endpoint zero FIFO to  
be transmitted. The UDC will automatically clear this bit when the packet has been successfully  
transmitted. When this bit is cleared, the EIR bit in the UDC status/interrupt register will be set if  
endpoint zero interrupts are enabled. The CPU will not be able to clear this bit.  
Sent Stall (SST)  
The sent stall bit is set by the UDC when it must abort the current control transfer by issuing a  
STALL handshake due to a protocol violation. When this bit is set, the EIR bit in the UDC  
status/interrupt register will be set if endpoint zero interrupts are enabled. The CPU clears this bit  
by writing a one to it.  
11.8.7.4  
11.8.7.5  
Force Stall (FST)  
The force stall bit can be set by the UDC to force the UDC to issue a STALL handshake. The UDC  
issues a STALL handshake for the current setup control transfer and the bit is cleared by the UDC  
because endpoint zero cannot remain in a stalled condition.  
Data End (DE)  
The data end bit is set by the UDC after it writes the last packet for the current descriptor. Once the  
current setup transfer has ended, the UDC clears this bit. When this bit is cleared the EIR bit in the  
UDC status/interrupt register will be set if endpoint zero interrupts are enabled. If there is no data  
phase, the CPU should set this bit at the same time it clears the OPR bit (0).  
11.8.7.6  
Setup End (SE)  
The setup end bit is set by the UDC when a control transfer ends before the DE bit (4) gets set.  
When this bit is set the EIR bit in the UDC status/interrupt register will be set if endpoint zero  
interrupts are enabled. This bit is cleared by writing a one to the serviced setup end bit (7). When  
the CPU detects this bit being set (if the OPR bit (0) is also set), then it should unload the new setup  
packet after it clears setup end.  
11.8.7.7  
Serviced OPR (SO)  
The serviced bit will clear the OPR bit (0) when writing a one.  
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Peripheral Control Module  
11.8.7.8  
Serviced Setup End (SSE)  
The serviced setup end bit will clear the SE bit (5) when writing a one.  
Address: 0h 8000 0010  
UDCCS0  
Read/Write  
Bit  
7
SSE  
0
6
SO  
0
5
SE  
0
4
3
FST  
0
2
SST  
0
1
IPR  
0
0
OPR  
0
DE  
0
Reset  
Bit  
Name  
Description  
0
1
2
3
4
5
6
7
OPR  
OUT packet ready (read-only).  
1 – OUT packet ready.  
IPR  
SST  
FST  
DE  
IN packet ready (read/write 1 to set).  
1 – IN packet ready.  
Sent stall (read/write 1 to clear).  
1 – UDC sent stall handshake.  
Force stall (read/write 1 to set).  
1 – Force stall handshake.  
Data end (read/write 1 to set).  
1 – The last byte of the data phase has been written.  
SE  
Setup end (read-only).  
1 – Control transfer ended before data end got set.  
SO  
Serviced OPR (write-only).  
1 – Clear OPR, bit 0.  
SSE  
Serviced setup end (write-only).  
1 – Clear SE, bit 5.  
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Peripheral Control Module  
11.8.8  
UDC Endpoint 1 Control/Status Register  
The UDC endpoint 1 control/status register contains 6 bits that are used to operate endpoint 1  
(OUT endpoint).  
11.8.8.1  
Receive FIFO Service (RFS)  
The receive FIFO service bit will be set if the receive FIFO has between 8 and 12 or more bytes  
(out of 20) in it. Because the FIFOs are asynchronous, the exact threshold cannot be determined,  
but is guaranteed to be in this range. This signal is also used as a DMA request signal to trigger the  
DMA unit to service the FIFO.  
11.8.8.2  
Receive Packet Complete (RPC)  
The receive packet complete bit gets set by the UDC when an OUT packet has been received.  
When this bit is set the RIR bit in the UDC status/interrupt register will be set if receive interrupts  
are enabled. This bit can be used to validate the other status/error bits in the endpoint 1  
control/status register. The RPC bit gets cleared by writing a one to it. The UDC will issue NAK  
handshakes to all OUT tokens while this bit is set.  
11.8.8.3  
11.8.8.4  
Receive Packet Error (RPE)  
The receive packet error bit will be set if a CRC, bit stuffing, or FIFO overrun error occurs. It is  
only valid if the RPC bit (1) is set and gets cleared when the RPC bit gets cleared.  
Sent Stall (SST)  
The sent stall bit is set by the UDC when it must abort the current transfer by issuing a STALL  
handshake due to a protocol violation (the host sends more data than the maximum packet size).  
The CPU clears this bit by writing a one to it.  
11.8.8.5  
11.8.8.6  
Force Stall (FST)  
The force stall bit can be set by the UDC to force the UDC to issue a STALL handshake to all OUT  
tokens. STALL handshakes will continue to be sent until the CPU clears this bit. The sent stall bit  
(3) will be set when the STALL state is actually entered (this may be delayed if the UDC is active  
when the FST bit is set), and the STALL state will not be exited until both the FST and SST bits are  
cleared.  
Receive FIFO Not Empty (RNE)  
The receive FIFO not empty bit indicates that there is unread data in the receive FIFO. This bit  
must be polled when the RPC bit is set to determine if there is any data in the FIFO that DMA did  
not read. The receive FIFO must continue to be read until this bit clears or data will be lost.  
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Peripheral Control Module  
11.8.8.7  
Bits 7..6 Reserved  
Bits 7..6 are reserved for future use.  
Address: 0h 8000 0014  
UDCCS1  
Read/Write  
Bit  
7
6
5
RNE  
0
4
3
SST  
0
2
RPE  
0
1
RPC  
0
0
RFS  
0
Res.  
FST  
0
Reset  
0
0
Bit  
Name  
Description  
Receive FIFO service (read-only).  
0
1
2
RFS  
0 – Receive FIFO has less than 12 bytes.  
1 – Receive FIFO has 12 bytes or more.  
Receive packet complete (read/write 1 to clear).  
0 – Error/status bits invalid.  
RPC  
RPE  
1 – Receive packet has been received and error/status bits are valid.  
Receive packet error (read-only).  
0 – Receive packet has no errors.  
1 – Receive packet has errors; valid only when RPC is set.  
Sent stall (read/write 1 to clear).  
3
4
SST  
FST  
1 – STALL handshake was sent; valid only when RPC is set.  
Force stall (read/write).  
1 – Issue STALL handshakes to OUT tokens.  
Receive FIFO not empty (read-only).  
0 – Receive FIFO empty.  
5
RNE  
1 – Receive FIFO not empty.  
Reserved.  
7..6  
Always reads zero.  
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Peripheral Control Module  
11.8.9  
UDC Endpoint 2 Control/Status Register  
The UDC endpoint 2 control status register contains 6 bits that are used to operate endpoint 2  
(IN endpoint).  
11.8.9.1  
Transmit FIFO Service (TFS)  
The transmit FIFO service bit will be active if there are 8 or less (out of 16) bytes remaining in the  
transmit FIFO. This bit will be used as a DMA request to trigger the DMA unit to service the  
transmit FIFO.  
11.8.9.2  
Transmit Packet Complete (TPC)  
The transmit packet complete bit will be set by the UDC when an entire packet has been sent to the  
host. When this bit is set, the TIR bit in the UDC status/interrupt register will be set if transmit  
interrupts are enabled. This bit can be used to validate the other status/error bits in the endpoint 2  
control/status register. The TPC bit gets cleared by writing a one to it. The UDC will issue NAK  
handshakes to all IN tokens while this bit is set.  
11.8.9.3  
11.8.9.4  
Transmit Packet Error (TPE)  
The transmit packet error bit acts as a status bit and will be valid while TPC is set. The TPE bit  
being set will indicate that the host did not issue an ACK handshake to the current packet. The TPE  
bit will be cleared when the TPC bit is cleared.  
Transmit Underrun (TUR)  
The transmit underrun bit will be set if the transmit FIFO experiences an underrun. This bit will be  
valid when the TPC bit is set. When the UDC experiences an underrun, the packet is shortened and  
the CRC is corrupted to ensure that the host discards the packet. The TUR bit will be cleared when  
the TPC bit is cleared.  
11.8.9.5  
11.8.9.6  
Sent STALL (SST)  
The sent stall bit indicates that a STALL handshake was issued to the host. The CPU writes a one to  
this bit to clear it. When this bit is cleared the transmit FIFO is flushed.  
Force STALL (FST)  
The CPU can set the force stall bit to force the UDC to issue a STALL handshake to all IN tokens.  
STALL handshakes will continue to be sent until the CPU clears this bit. The sent stall bit (4) will  
be set when the STALL state is actually entered (this may be delayed if the UDC is active when the  
FST bit is set), and the STALL state will not be exited until both the FST and SST bits are cleared.  
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Peripheral Control Module  
11.8.9.7  
Bits 7..6 Reserved  
Bits 7..6 are reserved for future use.  
Address: 0h 8000 0018  
UDCCS2  
Read/Write  
Bit  
7
6
5
FST  
0
4
3
TUR  
0
2
TPE  
0
1
TPC  
0
0
TFS  
0
Res.  
SST  
0
Reset  
0
0
Bit  
Name  
Description  
0
1
2
TFS  
Transmit FIFO service (read-only).  
0 – Transmit FIFO has more than 8 bytes.  
1 – Transmit FIFO has 8 bytes or less.  
TPC  
TPE  
Transmit packet complete (read/write 1 to clear).  
0 – Error/status bits invalid.  
1 – Transmit packet has been sent and error/status bits are valid.  
Transmit packet error (read-only).  
0 – Transmit packet was received with no errors.  
1 – Transmit packet has errors and the host did not issue ACK. Valid only when RPC is  
set.  
3
4
5
TUR  
SST  
FST  
Transmit FIFO underrun.  
1 – Transmit FIFO experienced an underrun. Valid only when TPC is set.  
Sent STALL (read/write 1 to clear).  
1 – STALL handshake was sent. Valid only when TPC is set.  
Force STALL (read/write).  
1 – Issue STALL handshakes to IN tokens.  
7..6  
Reserved.  
Always reads zero.  
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Peripheral Control Module  
11.8.10 UDC Endpoint 0 Data Register  
The UDC endpoint 0 data register is actually an 8-bit x 8-entry bidirectional FIFO. When the host  
transmits data to the UDC endpoint 0, the CPU reads the UDC endpoint 0 register to access the  
data. When the UDC is sending data to the host, the CPU writes the data to be sent into the UDC  
endpoint 0 register. Although the same FIFO can be read and written by the CPU during various  
points in a control sequence, the CPU may not read and write the FIFO at the same time. The  
direction that the FIFO is flowing is controlled by the UDC. Normally, the UDC will be in an idle  
state, waiting for the host to send commands. When this happens, the UDC fills the FIFO with the  
command from the host and the CPU reads the command from the FIFO once it has arrived. The  
UDC will do a partial decode of the command to determine if the CPU is going to be filling the  
FIFO with data to send to the host. If so, the direction is turned around to accept data from the CPU  
and have the UDC transmit the data. If the command is such that no data will be required from the  
UDC, then this will not happen. The only time the CPU may write the endpoint 0 FIFO is when a  
valid command from the host has been received which requires a transmission in response, that is,  
a GET_DESCRIPTOR command.  
Address: 0h 8000 001C  
UDCD0  
Read/Write  
Bit  
Reset  
Bit  
7
0
7
0
6
0
6
0
5
0
5
0
4
3
2
0
2
0
1
0
0
0
0
Bottom of Endpoint 0 FIFO  
0
0
3
0
1
0
Read Access  
4
Top of Endpoint 0 FIFO  
Reset  
0
0
Write Access  
Bit  
Name  
DATA  
Description  
7..0  
Top/bottom of endpoint 0 FIFO data.  
Read – Bottom of endpoint 0 FIFO data.  
Write – Top of endpoint 0 FIFO data.  
11.8.11 UDC Endpoint 0 Write Count Register  
The UDC endpoint 0 write count register can be read when a packet has been received by the  
endpoint 0 to determine how many bytes to read out of the UDC endpoint 0 data register. When  
data is present in the FIFO, this 4-bit field should read between 1 and 8.  
Address: 0h 8000 0020  
UDCWC  
Read-Only  
Bit  
Reset  
Bit  
7
6
5
0
4
0
3
0
2
1
0
0
Reserved  
Write Count  
0
0
0
0
Name  
Description  
3..0  
WC  
Endpoint 0 write count (read-only).  
4-bit field representing the number of bytes in the endpoint 0 FIFO.  
7..4  
Reserved.  
Always reads zero.  
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11.8.12 UDC Data Register  
The UDC data register (UDDR) is an 8-bit register corresponding to both the top and bottom  
entries of the transmit and receive FIFOs, respectively. Data is placed by the UDC’s receive logic  
into the top of the receive FIFO. The data is transferred down the FIFO to the lowest location that  
is empty. When UDDR is read, the bottom entry of the 8-bit receive FIFO is accessed. After the  
read, the bottom FIFO entry is invalidated, which causes all data in the FIFO to automatically  
transfer down one location.  
When UDDR is written, the topmost FIFO entry of the 8-bit transmit FIFO is accessed. After a  
write, the data is automatically transferred down the FIFO to the lowest location that is empty. The  
UDC’s transmit logic takes 8-bit values from the bottom of the transmit FIFO one at a time, places  
the data into a serial shifter, and transmits the value out onto the UDC pins. Each time a value is  
taken from the bottom entry, the location is invalidated, which causes all data in the FIFO to  
automatically transfer down one location.  
The following table shows the location of the top/bottom of the transmit/receive FIFOs in the UDC  
data register (UDDR). Note that both FIFOs are cleared when the SA-1100 is reset and when UDE  
is written to zero. After either of these actions takes place, the user may prime the transmit FIFO by  
writing up to sixteen 8-bit values to UDDR before enabling the UDC.  
Address: 0h 8000 0008  
UDDR  
Read/Write  
Bit  
Reset  
Bit  
7
0
7
0
6
0
6
0
5
0
5
0
4
3
2
0
2
0
1
0
0
0
0
Bottom of receive FIFO  
0
0
0
1
0
Read Access  
4
3
Top of transmit FIFO  
Reset  
0
0
Write Access  
Bit  
7..0  
Name  
DATA  
Description  
Top/bottom of transmit/receive FIFO data.  
Read – Bottom of receive FIFO data.  
Write – Top of transmit FIFO data.  
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11.8.13 UDC Status/Interrupt Register  
The UDC status/interrupt register (UDCSR) contains bits that are used to generate the UDC’s  
interrupt request. Each bit in the UDC status/interrupt register is logically ORed together to  
produce one interrupt request. When the ISR for the UDC is executed, it must read the UDC  
status/interrupt register to determine why the interrupt occurred.  
Every bit in the UDCSR is controlled by a mask bit in the UDC control register. The mask bits,  
when set, will prevent a status bit in the UDCSR from being set. If the mask bit for a particular  
status bit is cleared and an interruptible condition occurs, the status bit will be set. In order to clear  
status bits, the CPU must write a one into the position that it wishes to clear. The interrupt request  
for the UDC will remain active as long as the value of the UDCSR is non-zero.  
11.8.13.1 Endpoint 0 Interrupt Request (EIR)  
The endpoint 0 interrupt request will be set if the EIM bit in the UDC control register is cleared,  
and in the UDC endpoint 0 control/status register, the OUT packet ready bit gets set, the IN packet  
ready bit gets cleared, the data end bit gets cleared, the setup end bit gets set, or the sent STALL bit  
gets set. The EIR bit is cleared by writing a one to it.  
11.8.13.2 Receive Interrupt Request (RIR)  
The receive interrupt request bit gets set if the RIM bit in the UDC control register is cleared and  
the Receive Packet Complete bit in the UDC endpoint 1 control/status register gets set. The RIR bit  
is cleared by writing a one to it.  
11.8.13.3 Transmit Interrupt Request (TIR)  
The transmit interrupt request bit gets set if the TIM bit in the UDC control register is cleared and  
the Transmit Packet Complete bit in the UDC endpoint 2 control/status register gets set. The RIR  
bit is cleared by writing a one to it.  
11.8.13.4 Suspend Interrupt Request (SUSIR)  
The suspend interrupt request bit will be set if the SRM bit in the UDC control register is cleared and  
the USB bus remains idle for more than 3 ms. The SUSIR bit gets cleared by writing a one to it.  
11.8.13.5 Resume Interrupt Request (RESIR)  
The resume interrupt request bit will be set if the SRM bit in the UDC control register is cleared,  
the UDC is currently in the suspended state, and the USB bus is driven with resume signalling.  
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11.8.13.6  
Reset Interrupt Request (RSTIR)  
The reset interrupt request register will be set if the REM bit in the UDC control register is cleared  
and the host issues a reset. When the host issues a reset, the entire UDC is reset. The RSTIR bit  
retains its state so software can determine that the design was reset.  
Address: 0h 8000 0030  
UDCSR  
Read/Write (Clear)  
Bit  
7
6
5
RSTIR  
0
4
3
SUSIR  
0
2
1
RIR  
0
0
Res.  
RESIR  
0
TIR  
0
EIR  
0
Reset  
0
0
Bit  
Name  
Description  
0
1
2
3
4
5
EIR  
Endpoint 0 interrupt request (read/write clear).  
1 – Endpoint 0 needs service.  
RIR  
Receive interrupt request (read/write clear).  
1 – Receive endpoint (1) needs service.  
TIR  
Transmit interrupt request (read/write clear).  
1 – Transmit endpoint (2) needs service.  
SUSIR  
RESIR  
RSTIR  
Suspend interrupt request (read/write clear).  
1 – UDC received suspend signalling from the host.  
Resume interrupt request (read/write clear).  
1 – UDC received resume signalling from the host.  
Reset interrupt request (read/write clear).  
1 – UDC was reset by the host.  
7..6  
Reserved.  
Always reads zero.  
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11.8.14 UDC Register Locations  
Table 11-13 shows the registers associated with the UDC and the physical addresses used to access them.  
Table 11-13. UDC Control, Data, and Status Register Locations  
Address  
0h8000 0000  
Name  
UDCCR  
Description  
UDC control register  
UDC address register  
0h8000 0004  
0h8000 0008  
0h8000 000C  
0h8000 0010  
0h8000 0014  
0h8000 0018  
0h8000 001c  
0h8000 0020  
0h8000 0024  
0h8000 0028  
0h8000 002c  
0h8000 0030  
UDCAR  
UDCOMP  
UDCIMP  
UDCCS0  
UDCCS1  
UDCCS2  
UDCD0  
UDCWC  
UDC OUT max packet register  
UDC IN max packet register  
UDC endpoint 0 control/status register  
UDC endpoint 1 (OUT) control/status register  
UDC endpoint 2 (IN) control/status register  
UDC endpoint 0 data register  
UDC endpoint 0 write count register  
Reserved  
UDCDR  
UDC transmit/receive data register (FIFOs)  
Reserved  
UDCSR  
UDC status/interrupt register  
11.9  
Serial Port 1 – SDLC/UART  
Serial port 1 is a combination synchronous data link controller (SDLC) and universal asynchronous  
receiver/transmitter (UART) serial controller. The user can configure it to perform one of the two  
functions, but operation of both modes using serial port 1’s pins cannot occur simultaneously  
(SDLC transmit and UART receive). However, the peripheral pin control (PPC) unit can be  
configured to take control of two GPIO pins and use them for UART transmission, while serial  
port 1’s pins are used for SDLC operation. See the Section 11.13, “Peripheral Pin Controller  
(PPC)” on page 11-184 for a description of how the PPC is configured to allow use of both the  
SDLC and UART.  
For both protocols, serial port 1 can operate at baud rates from 56.24 bps to 230.4 Kbps. Both also  
contain an 11-bit wide by 12-entry deep receive FIFO and an 8-bit wide by 8-entry deep transmit  
FIFO to buffer incoming and outgoing data, respectively. The FIFOs can be filled or emptied either  
by the DMA or the CPU, with service requests being signalled when the transmit FIFO is  
half-empty and the receive FIFO is one- to two-thirds full.  
Used as an SDLC controller, serial port 1 supports much of the functionality found in commercial  
serial communications controllers, such as the 85C30. Frames contain an 8-bit address, an optional  
control field, a data field of any size that is a multiple of 8 bits, and a 16-bit CRC-CCITT. The start  
and stop flags and CRC generation and checking are handled automatically. Data can be selectively  
saved in the receive FIFO by programming an address with which to compare against all incoming  
frames. Interrupts are signalled when CRC checks performed on received data indicate an error,  
when a receiver abort occurs, when the transmit or receive FIFO needs to be filled or emptied,  
when the transmit FIFO underruns during an active frame and is aborted, when the receive FIFO  
overruns and data is lost, and when the last byte of data within a frame is contained within the  
bottom four entries of the receive FIFO.  
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Used as a UART, serial port 1 is identical to serial port 3. It supports most of the functionality of  
the 16C550 protocol including 7 and 8 bits of data (odd, even, or no parity), one start bit, either one  
or two stop bits, and transmits a continuous break signal. An interrupt is generated when a  
framing, parity, or receiver overrun error is present within the bottom four entries of the receive  
FIFO, when the transmit FIFO is half-empty or the receive FIFO is one- to two-thirds full, when a  
begin and end of break is detected on the receiver, and when the receive FIFO is partially full and  
the receiver is idle for three or more frame periods. Because programming and operation of serial  
port 1 as a UART is identical to serial port 3, see the Section 11.9, “Serial Port 1 – SDLC/UART”  
on page 11-78 for a complete description of using serial port 1 in UART mode.  
The external pins dedicated to this interface are TXD1 and RXD1. If serial transmission is not  
required and both the SDLC and UART are disabled, control of these pins is given to the peripheral  
pin control (PPC) unit for use as general- purpose input/output pins (noninterruptible). See the  
Modem control signals (RTS, CTS, DTR, and DSR) are not provided in this block but can be  
implemented using the general-purpose I/O port (GPIO) pins described in the Chapter 9, “System  
11.9.1  
SDLC Operation  
Following reset, both the SDLC and UART are disabled, which causes the peripheral pin controller  
(PPC) to assume control of the port’s pins. Reset causes the PPC to configure all of the peripheral  
pins as inputs, including serial port 1’s transmit (TXD1) and receive (RXD1) pins. Reset also  
causes the SDLC’s transmit and receive FIFOs to be flushed (all entries invalidated). Before  
enabling the SDLC, the user must first clear any writable or “sticky” status bits that are set by  
writing a one to each bit. Next, the desired mode of operation is programmed in the control  
registers. At this point, the user can “prime” the transmit FIFO by writing up to eight values, or the  
FIFO can remain empty and either programmed I/O or the DMA can be used to service it after the  
SDLC is enabled. Once the SDLC is enabled, transmission and reception of data can begin on the  
transmit (TXD1) and receive (RXD1) pins.  
11.9.1.1  
Bit Encoding  
SDLC uses frequency modulation zero (FM0) to encode individual bits. Both the clock and the  
data are encoded and transmitted on the same line. Instead of representing data by controlling the  
state of the line, its frequency is used. The line transitions at a frequency that represents the serial  
stream’s bit rate (this produces the clock). Individual bits are separated by each transition. A zero is  
encoded by placing an extra transition at the middle of its bit period. A one is represented by no  
added transitions within its bit period (this produces the data). Note that nonreturn to zero (NRZ)  
bit encoding can also be programmed in the SDLC. In NRZ encoding, a one is represented when  
the line transitions, and a zero when the line does not transition. Figure 11-22 shows both the NRZ  
and FM0 encoding of the data byte 8b 0100 1011. Note that the byte’s LSB is transmitted first.  
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Figure 11-22. FM0/NRZ Bit Encoding Example (0100 1011)  
LSB  
Bit  
MSB  
0
1
1
0
1
0
0
1
Value  
NRZ  
Data  
FM0  
Data  
11.9.1.2  
Frame Format  
SDLC uses a flag (reserved bit pattern) to denote the beginning of a frame of information and to  
synchronize frame transmission. The flag contains eight bits that start and end with a zero, and  
contains six sequential ones in the middle (01111110). This sequence of six ones is unique because  
all data between the start and stop flags is prohibited from having more than five consecutive ones.  
Data that violates this rule is altered before transmission by automatically inserting a zero after five  
consecutive ones are detected in the transmitted bit stream. This technique is commonly referred to  
as “bit stuffing” and is transparent to the user. The information field within an SDLC frame is  
placed between two flags and consists of an 8-bit address, an optional 8-bit control field, a data  
field containing any multiple of 8 bits, and a 16-bit cyclic redundancy check (CRC-CCITT). The  
user can also program the SDLC to insert an optional second start flag. Note that each byte within  
the address, control, and data fields is transmitted and received LSB first, ending with the byte’s  
MSB. However, the CRC is transmitted and received MSB first. Figure 11-23 shows the SDLC  
frame format.  
Figure 11-23. SDLC Frame Format  
8 Bits  
8 Bits  
8 Bits  
Any Multiple  
of 8 Bits  
8 Bits  
16 Bits  
8 Bits  
(optional)  
(optional)  
Start Flag  
0111 1110  
Start Flag  
0111 1110  
Stop Flag  
0111 1110  
Address  
Control  
Data  
CRC-CCITT  
11.9.1.3  
Address Field  
The 8-bit address field is used by a transmitter to target a select group of receivers when multiple  
stations are connected to the same set of serial lines. The address allows up to 255 stations to be  
uniquely addressed (00000000 to 11111110). The global address (11111111) is used to broadcast  
messages to all stations. Serial port 1 contains an 8-bit register that is used to program a unique  
address for broadcast recognition. It also contains a control bit to enable or disable the address  
match function. Note that the address of received frames is stored in the receive FIFO along with  
normal data; it is transmitted and received starting with its LSB and ending with its MSB.  
11.9.1.4  
Control Field  
The SDLC control field is typically 8 bits, but can be any length. Serial port 1 does not provide any  
hardware decode support for the control byte; it treats all bytes between the address and the CRC as data.  
Note that the control field is transmitted and received starting with its LSB and ending with its MSB.  
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11.9.1.5  
Data Field  
The data field can be any length that is a multiple of 8 bits, including zero. The user determines the  
data field length according to the application requirements and transmission characteristics of the  
target system. Usually a length is selected that maximizes the amount of data that can be  
transmitted per frame to allow the CRC checker to consistently detect all errors during  
transmission. Note that serial port 1 does not support residue coding found in common SCCs; all  
data fields must be a multiple of 8 bits. If a data field that is not a multiple of 8 bits is received, an  
abort is signalled and the end of frame tag is set within the receive FIFO. Also note that each byte  
within the data field is transmitted and received starting with its LSB and ending with its MSB.  
11.9.1.6  
CRC Field  
SDLC uses the established CCITT cyclic redundancy check (CRC) to detect bit errors that occur  
during transmission. A 16-bit CRC-CCITT is computed using the address, control, and data fields,  
and is included in each frame. A separate CRC generator is implemented in both the transmit and  
receive logic. The transmitter calculates a CRC while data is actively transmitted, and places the  
16-bit value at the end of each frame before the flag is transmitted. The receiver calculates a CRC  
for each received data frame, and compares the calculated CRC to the expected CRC value  
contained within the end of each received frame. If the calculated value does not match the  
expected value, an interrupt is signalled. The CRC computation logic is preset to all ones before  
reception or transmission of each frame. Note that, unlike all other fields within the frame, the  
CRC is transmitted and received starting with its MSB and ending with its LSB. The CRC logic  
uses the following four-term polynomial in the implementation of its linear feedback shift register.  
16  
12  
5
CRC(x)= (X + X + X + 1)  
11.9.1.7  
Baud Rate Generation  
The baud or bit rate is derived by dividing down the 3.6864-MHz clock generated by the on-chip  
PLL. The clock is first divided by a programmable number between 1 and 4096, and then by a  
fixed value of 16. The receive baud clock is synchronized with the data steam each time a transition  
is detected on the receive data line at a bit’s boundary. For FM0 encoding, zeros and ones are  
decoded within the incoming data stream by detecting whether a transition occurs between the  
boundaries of a bit time. If the receive line transitions, a zero is decoded; otherwise, a one is  
decoded. The baud synchronizer differentiates a transition of the receive line at the bit boundary  
from a transition caused by a zero by first establishing the bit boundary during reception of the  
string of ones within the flag (01111110). A counter is then used to cause the synchronizer to ignore  
transitions that occur during mid-bit. This is accomplished by using the clock produced before the  
fixed divide by 16 takes place. This clock is used to increment a counter that is reset at the  
boundary of each bit. Transitions that take place at any time before the counter reaches the value 12  
(3/4 of a total bit time) are ignored. This function effectively masks a transition, which occurs  
during reception of a zero, excluding it from the bit synchronization process. When NRZ encoding  
is used, each bit of received data is sampled at its midpoint by using the clock that is generated  
before the fixed divide by 16 takes place. A sample rate counter is used that is reset at the boundary  
of each bit and is incremented using this clock. When it reaches a value of 8 (halfway through the  
bit period), the receive data pin is sampled.  
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11.9.1.8  
Receive Operation  
Once the SDLC receiver is enabled, it enters hunt mode, searching the incoming data stream for the  
flag (01111110). The flag serves to achieve bit synchronization, denotes the beginning of a frame,  
and delineates the boundaries of individual bytes of data. The end of the flag denotes the beginning  
of the address byte. Once the flag is found, the receiver is synchronized to incoming data and hunt  
mode is exited.  
After each bit is decoded, a serial shifter is used to receive the incoming data a byte at a time. Once  
the flag is recognized, each subsequent byte of data is decoded and placed within a 2-byte  
temporary FIFO. A temporary FIFO is used to prevent the CRC from being placed within the  
receive FIFO. When the temporary FIFO is filled, data values are pushed out one by one to the  
receive FIFO. The first byte of a frame is the address. If receiver address matching is enabled, the  
received address is compared to the address programmed in the address match value field in a  
control register. If the two values are equal or if the incoming address contains all ones, all  
subsequent data bytes including the address byte are stored in the receive FIFO. If the values do not  
match, the receive logic does not store any data in the receive FIFO, ignores the remainder of the  
frame, and begins to search for the stop flag. The second byte of the frame can contain an optional  
control field, which must be decoded in software (no hardware support within the SDLC). Use of a  
control byte is determined by the user.  
When the receive FIFO is one- to two-thirds full, an interrupt and/or DMA request is signalled. If  
the data is not removed soon enough, and the FIFO is completely filled, an overrun error is  
generated when the receive logic attempts to place additional data into the full FIFO. Once the  
FIFO is full, all subsequent data bytes received are lost while all FIFO contents remain intact.  
Frames can contain any amount of data in multiples of 8 bits. Although the SDLC protocol does  
not limit frame size, in practice they tend to be implemented in numbers ranging from hundreds to  
thousands of bytes.  
The receive logic continuously searches for the stop flag at the end of the frame. Once it is  
recognized, the last byte that was placed within the receive FIFO is flagged as the last byte of the  
frame, and the two bytes remaining within the temporary FIFO are removed and used as the 16-bit  
CRC value for the frame. Instead of placing this in the receive FIFO, the receive logic compares it  
to the CRC-CCITT value, which is continuously calculated using the incoming data stream. If they  
do not match, the last byte that was placed within the receive FIFO is also flagged with a CRC  
error. The CRC value is not placed in the receive FIFO.  
The SDLC protocol permits back-to-back frames to be received. When this occurs, the flag at the  
end of the first frame also serves as the flag to denote the beginning of the next frame (only one  
flag separates the two). Most commercial SCCs continuously transmit flags between frames when  
they do not occur back-to-back. To support both of these cases, the receive logic allows one or  
more flags to separate frames. When the use of two start flags is programmed by the user, two flags  
always separate back-to-back frames that are transmitted.  
Most commercial SCCs can generate an abort (7 to 13 ones) when their transmit FIFO underruns.  
The receive logic contains a counter that increments each time a one is decoded before entering the  
serial shifter and is reset any time a zero is decoded. When seven or more ones are detected, a  
receiver abort occurs. Note that data is moved from the serial shifter to the temporary FIFO a byte  
at a time, and seven consecutive ones may bridge two bytes. For this reason, after an abort is  
detected, the remaining data in the serial shifter is discarded along with the most recent byte of data  
placed in the temporary FIFO. After this data is discarded, the oldest byte of data in the temporary  
FIFO is placed in the receive FIFO, the EOF tag is set within the top entry of the FIFO (next to the  
byte transferred from the temporary FIFO), the receiver abort interrupt is signalled, and the  
receiver logic enters hunt mode until it recognizes the next flag.  
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If the user disables the receiver during operation, reception of the current data byte is stopped  
immediately, the serial shifter and receive FIFO are cleared, control of the RXD1 pin is given to  
the peripheral pin control (PPC) unit, and all clocks used by the receive logic are automatically shut  
off to conserve power. However, the transmitter continues to function as normal.  
11.9.1.9  
Transmit Operation  
The SDLC transmit logic can operate at the same time as the receive logic (full-duplex). The user  
may either “prime” the transmit FIFO by filling it with data or allow service requests to cause the  
CPU or DMA to fill the FIFO once the SDLC transmitter is enabled. Once enabled, the transmit  
logic issues a service request if its FIFO is empty. Flags are transmitted continuously until valid  
data resides within the FIFO. Once a byte of data resides at the bottom of the transmit FIFO, it is  
transferred to the serial shifter. It is encoded and shifted out onto the TXD1 pin clocked by the  
programmed baud rate clock. Note that the flag and CRC value are automatically transmitted and  
need not be placed in the transmit FIFO.  
When the transmit FIFO is emptied halfway, an interrupt and/or DMA service request is signalled. If  
new data is not supplied soon enough, the FIFO is completely emptied and the transmit logic attempts  
to take additional data from the empty FIFO. The user can program one of two actions: an underrun to  
signal the normal completion of a frame or an unexpected termination of a frame in progress.  
When normal frame completion is selected and an underrun occurs, the transmit logic transmits the  
16-bit CRC value calculated during the transmission of all data within the frame (including the  
address and control bytes), followed by a flag to denote the end of the frame. The transmitter then  
continuously transmits flags until data is once again available within the FIFO. Once data is  
available, the transmitter begins transmission of the next frame.  
When unexpected frame termination is selected and an underrun occurs, the transmit logic outputs  
an abort and interrupts the CPU. An abort continues to be transmitted until data is once again  
available in the transmit FIFO. The SDLC then transmits a flag and starts the new frame. The  
off-chip receiver can choose to ignore the abort and continue to receive data, or to signal serial port  
1 to retry transmission of the aborted frame.  
If the user disables the transmitter during operation, transmission of the current data byte is stopped  
immediately, the serial shifter and transmit FIFO are cleared, control of the TXD1 pin is given to  
the peripheral pin control (PPC) unit, and all clocks used by the transmit logic are automatically  
shut off to conserve power. However, the receiver continues to function as normal.  
11.9.1.10 Simultaneous Use of the UART and SDLC  
Serial port 1 contains a control bit to select which serial protocol to use: SDLC or UART. Note that  
the two protocols cannot be combined at the same time (SDLC transmit and UART receive).  
However, since the SDLC and UART are fully independent blocks, a mode is supported that allows  
the user to enable the SDLC using serial port 1’s pins (TXD1 and RXD1) while the UART is  
enabled using two GPIO pins (GPIO<14> for transmit and GPIO<15> for receive operation). This  
mode is enabled by setting the UART pin reassignment (UPR) control bit within the peripheral pin  
that when this mode is enabled, serial port 1’s control bit, which selects SDLC versus UART  
operation, is ignored and serial port 1 defaults to SDLC mode.  
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11.9.1.11 Transmit and Receive FIFOs  
To reduce chip size and power consumption, the SDLC’s FIFOs use self-timed logic (they are not  
clocked). Because of process and environmental variations, the depth at which a service request is  
triggered to empty the receive FIFO is variable. This variation spans a maximum of four FIFO  
entries; the receive FIFO service request can be made at four different FIFO depths. To  
compensate for this variability and guarantee that at least four valid entries of data exist within the  
FIFO before generating a service request, an extra four entries have been added to the receive FIFO  
(four entries more than the transmit FIFO). The transmit FIFO is 8 entries deep and the receive  
FIFO is 12 entries deep. The point at which the receive FIFO service request is triggered spans the  
middle third of the 12-entry FIFO. The service request is signalled at a depth from one-third full to  
two-thirds full or when the FIFO contains five, six, seven, or eight entries of data.  
This service request variation applies only to an empty FIFO that is filled (receive FIFO). It does  
not apply to a full FIFO that is emptied (transmit FIFO). The transmit FIFO is guaranteed to signal  
a service request when it has four or more empty entries and negate the request when the FIFO  
contains five or more entries that are filled.  
If the DMA is used to service either one or both of the SDLC’s FIFOs, the burst size must be set to  
4 words, even though more than four entries of data may exist within the receive FIFO. If  
programmed I/O is used to service the FIFOs, a maximum of 4 words may be added to the transmit  
FIFO without checking if more space is available. Likewise, a maximum of 4 words may be  
removed from the receive FIFO without checking if more data is available. After this point, the  
user must poll a set of status bits that indicate if any data remains in the receive FIFO or if space is  
available in the transmit FIFO before emptying or filling the FIFOs any further.  
11.9.1.12 CPU and DMA Register Access Sizes  
Bit positioning, byte ordering, and addressing of the SDLC is described in terms of little endian  
ordering. All SDLC registers are 8 bits wide and are located in the least significant byte of  
individual words. The ARM peripheral bus does not support byte or half-word operations. All  
reads and writes of the SDLC by the CPU should be wordwide. Two separate dedicated DMA  
requests exist for both the transmit and the receive FIFOs. If the DMA controller is used to service  
the transmit and/or receive FIFOs, the user must ensure that the DMA is properly configured to  
perform byte-wide accesses, using 4 bytes per burst (half the size of the FIFOs). Note that a  
separate set of registers also exist to configure UART operation.  
programming and the operation of serial port 1 as a UART.  
11.9.2  
SDLC Register Definitions  
There are eight registers within serial port 1: five control registers, one data register, and two status  
registers. The control registers are used to select UART or SDLC mode, baud rate, number of start  
flags, bit modulation mode, and address match value. They are used to select whether an abort or  
end of frame occurs when the transmit FIFO underruns, whether the sample clock is an input or  
output, and which edge of the sample clock is used to sample receive data and drive transmit data.  
Also they are used to enable or disable the FIFO interrupt service request, sample clock  
input/output operation, aborts after frames, receive operation, transmit operation, receive address  
for a full description of UART programming and operation.  
The data register addresses the top location of the transmit FIFO and bottom location of the receive FIFO.  
When it is read, the receive FIFO is accessed, and when it is written, the transmit FIFO is accessed.  
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Peripheral Control Module  
The status registers contain bits that signal CRC, overrun, underrun, and receiver abort errors, and  
the transmit FIFO service request, receive FIFO service request, and end-of-frame conditions. Each  
of these hardware-detected events signals an interrupt request to the interrupt controller. The status  
registers also contains flags for transmitter busy, receiver synchronized, receive FIFO not empty,  
transmit FIFO not full, and receive transition detect (no interrupt generated).  
11.9.3  
SDLC Control Register 0  
SDLC control register 0 (SDCR0) contains 8 bit fields that control various functions within the SDLC.  
11.9.3.1  
SDLC/UART Select (SUS)  
The SDLC/UART select (SUS) bit is used to select whether serial port 1 is used for SDLC or  
UART operation. When SUS=0, SDLC operation is selected. The receiver and transmitter logic is  
then enabled individually by programming the transmitter and receiver enable bits (TXE, RXE).  
When SUS=0 and TXE=0, control of the transmit pin (TXD1) is given to the PPC unit; when  
SUS=0 and RXE=0, control of the receive pin (RXD1) is given to the PPC unit. When SUS=1,  
UART operation is selected and the state of all remaining SDLC register bits is ignored (remaining  
unchanged) and control of the TXD1 and RXD1 pins is given to the UART. See the Section 11.9,  
“Serial Port 1 – SDLC/UART” on page 11-78 for a description of the programming and operation  
of serial port 1 as a UART. SUS, TXE, and RXE are the only bits within the control register that are  
reset placing serial port 1 into SDLC mode while disabling the transmitter and receiver.  
The user also has the ability to take control of two GPIO pins and use them for UART serial  
transmission while the SDLC makes use of serial port 1’s transmit and receive pins to allow both  
units to be used at the same time. The peripheral pin control (PPC) unit can be programmed to  
connect the UART’s transmit and receive lines to GPIO pins 14 and 15. When the UART pin  
reassignment (UPR) bit is set in the PPC pin assignment register (PPAR), the UART transmits using  
the GPIO<14> pin and receives using the GPIO<15> pin. The SUS bit is ignored in this case and  
serial port 1 operation defaults to SDLC mode. Note that the user must set bits 14 and 15 in the GPIO  
alternate function register (GAFR), and set bit 14 and clear bit 15 in the GPIO pin direction register  
(GPDR). See the “Peripheral Pin Controller (PPC)” on page 11-184 for a description of how to  
program the PPC and the Section 9.1, “General-Purpose I/O” on page 9-1 for a description of how to  
program the GPIO unit for this mode of operation.  
11.9.3.2  
11.9.3.3  
Single/Double Flag Select (SDF)  
The single/double flag select (SDF) bit is used to select whether one or two flags (01111110) are  
transmitted at the start of each frame. When SDF=0, the transmit logic uses one flag. When  
SDF=1, the transmit logic uses two flags. Note that SDF does not affect the number of flags that  
are transmitted at the end each frame (one flag is always used). Normally, when back-to-back  
transmissions are made, only one flag is inserted between the two frames (one flag serves as both  
the frame’s start and end flag). However, when SDF=1, two flags are inserted between each frame.  
SDF does not affect SDLC receive operation.  
Loopback Mode (LBM)  
The loopback mode (LBM) bit is used to enable and disable the ability of the SDLC transmit and  
receive logic to communicate. When LBM=0, the SDLC operates normally. The transmit and receive  
data paths are independent and communicate via their respective pins. When LBM=1, the output of  
the transmit serial shifter is directly connected to the input of the receive serial shifter internally, and  
control of the TXD1 and RXD1 pins are given to the peripheral pin control (PPC) unit.  
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Peripheral Control Module  
11.9.3.4  
Bit Modulation Select (BMS)  
The bit modulation select (BMS) bit selects whether the SDLC uses NRZ or FM0 bit encoding for  
both transmit and receive data. When BMS=0, FM0 encoding is selected and when BMS=1, NRZ  
encoding is selected. In frequency modulation zero (FM0) encoding, a transition occurs on every  
bit boundary. Zeros are represented by an additional transition in the middle of the bit period, and  
ones are represented by the lack of an additional transition in the middle of the bit period. In  
nonreturn to zero (NRZ) encoding, a one is represented when the pin is high, and a zero when the  
pin is low. Note that bit-stuffing/bit-extraction (the insertion/deletion of a zero after five ones are  
encountered) is not affected by BMS. Also note that NRZ encoding must be selected (BMS=1)  
when sample clock operation is enabled (SCE=1).  
11.9.3.5  
11.9.3.6  
Sample Clock Enable (SCE)  
The sample clock enable (SCE) bit is used to enable or disable driving or receiving a clock using  
GPIO pin 16 for synchronous transmission/reception of data. When SCE=0, the on-chip  
3.6864-MHz PLL, the SDLC’s programmable baud rate generator, and the receive logic’s digital  
PLL are used. When SCE=1, the sample clock direction (SCD) bit is decoded to determine the  
direction of the clock used on GPIO pin 16.  
Sample Clock Direction (SCD)  
When the sample clock function is enabled (SCE=1), the sample clock direction (SCD) bit is used  
to select whether the sample clock is an input from or an output to GPIO pin 16.  
When SCD=0, the sample clock is input using GPIO pin 16 and is used to synchronously drive both  
the transmit and receive logic. For the receive logic, the RCE bit is decoded to select which edge of  
the input clock is used to latch each bit of the incoming frame. Note that the clock is not embedded  
within the data stream, and the digital PLL is shut down to conserve power. For the transmit logic, the  
TCE bit is decoded to select which edge of the input clock is used to drive each bit of the outgoing  
frame. The on-chip clock used to drive the programmable baud rate generator is shut down to  
conserve power. Note that input clock frequency to GPIO<16> cannot exceed 3.6864 MHz.  
When SCD=1, the sample clock, which is generated within the SDLC unit (the clock that is output  
after dividing the 3.6864-MHz reference by the programmable BCD field, but before the fixed  
divide by 16), is output to GPIO pin 16, and again the RCE and TCE bits are decoded to determine  
which edge of this clock output is used to sample receive data and drive transmit data. Because the  
baud clock that is generated before the fixed divide by 16 is used to synchronously drive the SDLC,  
the effective baud rate is 16 times greater, allowing the SDLC to operate at speeds ranging from  
899.78 bps to 3.6864 Mbps.  
When the sample clock function is enabled (SCE=1), the user must program the SDLC bit  
modulation select (BMS) control bit to select NRZ encoding (BMS=1). Unpredictable results occur  
when FM0 encoding is selected during sample clock operation. Note that the SDLC frame format  
is not affected during sample clock operation, only the sampling and driving of individual data bits.  
Bit stuff (insertion of a zero after five consecutive ones) still occurs during NRZ encoding.  
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Peripheral Control Module  
11.9.3.7  
11.9.3.8  
Receive Clock Edge Select (RCE)  
When sample clock operation is enabled (SCE=1), the receive clock edge select (RCE) bit is used  
to select which edge of the clock input from or output to GPIO pin 16 to use (rising or falling) to  
synchronously sample data from the receive pin. When RCE=0, each bit received is sampled on the  
rising edge of the sample clock; when RCE=1, bits are sampled on the clock’s falling edge. Note  
that the internal baud rate generator and receive logic’s digital PLL are not used in this mode.  
Transmit Clock Edge Select (TCE)  
When sample clock operation is enabled (SCE=1), the transmit clock edge select (TCE) bit is used  
to select which edge of the clock input from or output to GPIO pin 16 to use (rising or falling) to  
synchronously drive data onto the transmit pin. When TCE=0, each bit transmitted is driven on the  
rising edge of the sample clock; when TCE=1, bits are driven on the clock’s falling edge. Note that  
the internal baud rate generator is not used in this mode.  
The following table shows the location of all bit fields located in SDLC control register 0  
(SDCR0). The SDLC must be disabled (SUS=RXE=TXE=0) when changing the state of any bit  
within this register. The reset state of all control bits except SUS is unknown (indicated by question  
marks) and must be initialized before enabling the SDLC.  
.
Address: 0h 8002 0060  
SDCR0  
Read/Write  
Bit  
7
TCE  
?
6
5
4
3
BMS  
?
2
LBM  
?
1
SDF  
?
0
SUS  
0
RCE SCD  
SCE  
?
Reset  
?
?
Bit  
Name  
Description  
0
SUS  
SDLC/UART select.  
0 – SDLC mode selected.  
1 – UART mode selected.  
Note: For SUS=0, if TXE=0, TXD1 control is given to PPC unit; if RXE=0, RXD1 control is  
given to PPC unit. If UPR is set in the PPC unit, SUS is ignored, the UART uses  
GPIO<14> to transmit and GPIO<15> to receive data, and serial port 1 defaults to SDLC  
mode. The user must also program the GAFR and GPDR registers appropriately in the  
GPIO unit.  
1
SDF  
Single/double flag select.  
0 – One flag generated at start of each transmit frame.  
1 – Two flags generated at start of each transmit frame.  
Note: SDF does not affect receive operation.  
2
3
LBM  
BMS  
Loopback mode.  
0 – Normal serial port operation enabled.  
1 – Output of transmit serial shifter is connected to input of receive serial shifter internally  
and control of TXD1 and RXD1 pins is given to the PPC unit.  
Bit modulation select.  
0 – FM0 bit encoding/decoding selected.  
1 – NRZ bit encoding/decoding selected.  
Note: BMS must be programmed to select NRZ (BMS=1) encoding when sample clock  
operation is enabled (SCE=1).  
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Peripheral Control Module  
4
SCE  
Sample clock enable.  
0 – On-chip baud rate generator and digital PLL used to transmit and receive SDLC data.  
1 – A clock is input or output via GPIO pin 16 and is used to synchronously sample  
receive data and drive transmit data.  
Note: BMS must be programmed to select NRZ encoding when sample clock operation is  
enabled (BMS=1).  
5
SCD  
Sample clock direction.  
0 – If sample clock enabled, it is input using GPIO pin 16.  
1 – If sample clock enabled, the sample clock generated by the programmable baud rate  
generator but before the fixed divide by 16 is output using GPIO pin 16.  
Note: For both directions, the sample clock is used to synchronously sample receive data  
and drive transmit data on the edges selected using RCE and TCE. A maximum of  
3.6864-MHz clock allowed.  
6
7
RCE  
TCE  
Receive clock edge select.  
0 – Rising edge of clock input/output on GPIO pin 16 used to latch data from the receive pin.  
1 – Falling edge of clock input/output on GPIO pin 16 used to latch data from the receive pin.  
Transmit clock edge select.  
0 – Rising edge of clock input/output on GPIO pin 16 used to drive data onto the transmit pin.  
1 – Falling edge of clock input/output on GPIO pin 16 used to drive data onto the transmit pin.  
11.9.4  
SDLC Control Register 1  
SDLC control register 1 (SDCR1) contains eight bit fields that control various functions within the  
SDLC.  
11.9.4.1  
Abort After Frame (AAF)  
The abort after frame (AAF) bit controls whether or not the SDLC transmits an abort at the end of  
each frame transmitted, and also controls the state of GPIO pin 17. When the AAF bit is set, each  
time the SDLC completes transmission of the flag at the end of a frame, the transmit logic signals  
an abort by transmitting 12 sequential ones on the transmit pin (TXD1). Additionally, any time the  
transmitter is idle (not sending a frame or the abort at the end of the frame), the SDLC forces GPIO  
pin 17 high. Likewise, when the SDLC is actively transmitting a frame (including the start and stop  
flags, and the abort at the end of the frame), it forces GPIO pin 17 low. If the transmit FIFO is  
emptied at the end of a frame, the abort is signalled followed by the continuous transmission of  
flags. If there is data present within the FIFO (indicating a new frame is available), the abort is  
followed by the programmed number of start flags, then data transmission begins again. For this  
case, GPIO<17> is not asserted because the two frames occur back-to-back (no idle time between  
the two frames). Note that the user must configure GPIO<17> as an output by setting the pin  
direction bit for pin 17 within GPDR. When AAF=1, the state of GPIO<17> is controlled solely by  
serial port 1. Writing to the pin set (GPSR) or pin clear (GPCR) registers for pin 17 has no effect.  
See Chapter 9, “System Control Module” for a description of GPIO programming.  
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Peripheral Control Module  
11.9.4.2  
Transmit Enable (TXE)  
The transmit enable (TXE) bit is used to enable and disable SDLC transmit operation. When  
TXE=0, the transmit logic is disabled and its clocks are turned off to conserve power. When  
TXE=1, the SDLC transmitter logic is enabled for serial transmission. It is required that the user  
first program all other control bits before setting TXE. If the TXE bit is cleared to zero while the  
SDLC is actively transmitting data, transmission is stopped immediately, all data within the  
transmit FIFO and serial output shifter is cleared, and control of the TXD1 pin is given to the  
peripheral pin control (PPC) unit. Note that SUS, TXE, and RXE are the only control bits within  
the SDLC that are initialized when a hardware reset occurs. Clearing TXE to zero ensures the  
SDLC transmitter is disabled, giving control of the transmit pin to the PPC unit, which configures  
TXD1 as an input following a reset of the SA-1100. Note that TXE is ignored when SUS=1  
(enables UART operation).  
11.9.4.3  
Receive Enable (RXE)  
The receive enable (RXE) bit is used to enable or disable SDLC receive operation. When RXE=0,  
the receive logic is disabled and its clocks are turned off to conserve power. When RXE=1, the  
SDLC receiver logic is enabled for serial reception. It is required that the user first program all  
other control bits before setting RXE. If the RXE bit is cleared to zero while the SDLC is actively  
receiving data, reception is stopped immediately, all data within the receive FIFO and serial input  
shifter is cleared, and control of the RXD1 pin is given to the peripheral pin control (PPC) unit.  
Note that SUS, TXE, and RXE are the only control bits within the SDLC that are initialized when a  
hardware reset occurs. Clearing RXE to zero ensures the SDLC receiver is disabled, giving control  
of the receive pin to the PPC unit, which configures RXD1 as an input following a reset of the  
SA-1100. Note that RXE is ignored when SUS=1 (enables UART operation).  
11.9.4.4  
Receive FIFO Interrupt Enable (RIE)  
The receive FIFO interrupt enable (RIE) bit is used to mask or enable the receive FIFO service  
request interrupt. When RIE=0, the interrupt is masked and the state of the receive FIFO service  
request (RFS) bit within SDLC status register 0 is ignored by the interrupt controller. When RIE=1,  
the interrupt is enabled and whenever RFS is set (one), an interrupt request is made to the interrupt  
controller. Note that programming RIE=0 does not affect the current state of RFS or the receive  
FIFO logic’s ability to set and clear RFS; it only blocks the generation of the interrupt request. Also  
note that RIE does not affect generation of the receive FIFO DMA request, which is asserted  
whenever RFS=1.  
11.9.4.5  
Transmit FIFO Interrupt Enable (TIE)  
The transmit FIFO interrupt enable (TIE) bit is used to mask or enable the transmit FIFO service  
request interrupt. When TIE=0, the interrupt is masked and the state of the transmit FIFO service  
request (TFS) bit within SDLC status register 0 is ignored by the interrupt controller. When TIE=1,  
the interrupt is enabled, and whenever TFS is set (one), an interrupt request is made to the interrupt  
controller. Note that programming TIE=0 does not affect the current state of TFS or the transmit  
FIFO logic’s ability to set and clear TFS; it only blocks the generation of the interrupt request. Also  
note that TIE does not affect generation of the transmit FIFO DMA request, which is asserted  
whenever TFS=1.  
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Peripheral Control Module  
11.9.4.6  
Address Match Enable (AME)  
The address match enable (AME) bit is used to enable or disable the receive logic from comparing  
the address programmed in the address match value (AMV) bit field to the address of all incoming  
frames. When AME=1, data is stored in the receive FIFO for only those frames that have  
addresses that match AMV, and for any frame that contains an address that contains all ones  
(11111111), denoting a global address. For frames in which the address does not match, the data  
and CRC are ignored and the receiver begins to search for the next flag. When AME=0, address  
values are not compared and the data in every frame is stored in the receive FIFO.  
11.9.4.7  
Transmit FIFO Underrun Select (TUS)  
The transmit FIFO underrun select (TUS) bit is used to select what action to take as a result of a  
transmit FIFO underrun and to mask or enable the transmit FIFO underrun interrupt.  
When TUS=0, transmit FIFO underruns are used to signal the transmit logic that the end of the  
frame has been reached. When the transmit FIFO experiences an underrun, the CRC value, which  
is calculated continuously on outgoing data, is loaded to the serial shifter and transmitted, followed  
by a flag. Also when TUS=0, the transmit FIFO interrupt is masked and the state of the transmit  
FIFO underrun (TUR) status bit is ignored by the interrupt controller.  
When TUS=1, transmit FIFO underruns are used to signal the transmit logic that the end of the  
frame has not yet been reached and that the rate in which data is supplied to the transmit FIFO is  
not sufficient. When the transmit FIFO experiences an underrun, ones are continuously output by  
the transmitter to signal an abort condition until data is once again available within the transmit  
FIFO, and the CRC value is discarded. Additionally, when TUS=1, the transmit FIFO underrun  
interrupt is enabled, and whenever TUR is set (one), an interrupt request is made to the interrupt  
controller. To change the state of this bit during operation, the user should fill the transmit FIFO to  
ensure TUS is not written at the same time the transmit FIFO underruns. Note that programming  
TUS=0 does not affect the current state of TUR or the transmit FIFO logic’s ability to set and clear  
TUR; it only blocks the generation of the interrupt request.  
TUS is useful for ensuring that frames are not prematurely ended due to an unexpected transmit FIFO  
underrun. At the start of a frame, the user can configure TUS=1 so that any underrun signals an abort  
to the off-chip receiver. Just before the end of the frame, the user can then configure TUS=0 (the last  
time the transmit FIFO is filled, for example), allowing the remaining data to be output by the  
transmit logic. The FIFO then underruns, causing the CRC and end flag to be transmitted.  
11.9.4.8  
Receiver Abort Interrupt Enable(RAE)  
The receiver abort interrupt enable (RAE) bit is used to mask or enable whether or not an abort  
sequence, which is detected by the receive logic, generates an interrupt to the CPU. When RAE=0,  
the interrupt is masked and the state of the receiver abort status (RAS) bit is ignored by the  
interrupt controller. When RAE=1, the interrupt is enabled and whenever RAS is set (one), an  
interrupt request is made to the interrupt controller. Note that programming RAE=0 does not affect  
the current state of RAS or the receive logic’s ability to set and clear RAS as the result of an abort  
detect; it only blocks the generation of the interrupt request.  
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Peripheral Control Module  
The following table shows the location of the bits within SDLC control register 1. RXE and TXE are  
the only control bits in this register that are reset to a known state to ensure the SDLC is disabled  
following a reset of the SA-1100. The reset state of all other control bits is unknown (indicated by  
question marks) and must be initialized before enabling the SDLC. Note that SDCR1 may be written  
while the SDLC is enabled to allow various modes to be changed during active operation.  
Address: 0h 8002 0064  
SDCR1  
Read/Write  
Bit  
7
6
5
4
3
2
1
0
RAE  
?
TUS  
?
AME  
?
TIE  
?
RIE  
RXE  
0
TXE  
0
AAF  
?
Reset  
?
Bit  
Name  
Description  
0
AAF  
Abort after frame.  
0 – Aborts not signalled following transmission of a frame. GPIO<17> controlled by system  
unit.  
1 – Abort is signalled after the end flag of a frame by transmitting 12 ones. GPIO<17> pin  
forced high during idle; forced low during transmission of a frame or the abort.  
Note: The user must configure GPIO<17> as an output within GPDR in the system  
control  
module.  
1
2
3
TXE  
RXE  
RIE  
Transmit enable.  
0 – SDLC transmit logic disabled. Control of the TXD1 pin is given to the PPC unit if SUS=0.  
1 – SDLC transmit logic enabled if SUS=0.  
Receive enable.  
0 – SDLC receive logic disabled. Control of the RXD1 pin is given to the PPC unit if SUS =0.  
1 – SDLC receive logic enabled if SUS=0.  
Receive FIFO interrupt enable.  
0 – Receive FIFO one- to two-thirds full or more condition does not generate an interrupt  
(RFS bit ignored).  
1 – Receive FIFO one- to two-thirds full or more condition generates an interrupt (state of  
RFS sent to interrupt controller).  
4
5
TIE  
Transmit FIFO interrupt enable.  
0 – Transmit FIFO half-full or less condition does not generate an interrupt (TFS bit ignored).  
1 – Transmit FIFO half-full or less condition generates an interrupt (state of TFS sent to  
interrupt controller).  
AME  
Address match enable.  
0 – Disable receiver address match function. Stores data from all incoming frames in  
receive FIFO.  
1 – Enable receiver address match function. Do not FIFO data unless address  
recognized or incoming address contains all ones (0hFF).  
6
7
TUS  
RAE  
Transmit FIFO underrun select.  
0 – Transmit FIFO underrun. Causes CRC and a flag to be transmitted, and masks  
interrupt generation (TUR ignored).  
1 – Transmit FIFO underrun. Causes an abort to be transmitted, and generates an  
interrupt (state of TUR sent to interrupt controller).  
Receiver abort interrupt enable.  
0 – Abort detected by the receiver. Does not generate an interrupt (RAS bit ignored).  
1 – Abort detected by the receiver. Generates an interrupt (state of RAS sent to interrupt  
controller).  
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11.9.5  
SDLC Control Register 2  
SDLC control register 2 (SDCR2) contains the 8-bit address match value field that is used by the  
SDLC to selectively receive frames.  
11.9.5.1  
Address Match Value (AMV)  
The 8-bit address match value (AMV) field is programmed with an address value that is used to  
selectively store only the data within receive frames that have the same address value. The address  
match enable (AME) bit must be set to enable this function. For incoming frames, which have the  
same address value as the AMV field, the frame’s address, control, and data are stored in the  
receive FIFO. For those that do not, the remainder of the frame is ignored, and the receive logic  
looks for the next start flag in the incoming data stream. One special address exists that is always  
matched by the address match logic regardless of the value programmed in AMV. When address  
matching is enabled, whenever a frame is received with an address containing all ones (11111111),  
the value programmed in AMV is ignored and the frame data is automatically stored in the receive  
FIFO. The address value is contained within the first byte of data in a frame following the flag.  
AMV can be written at any time, and is used for comparison for the next frame that occurs  
following its update.  
The following table shows the address match value field within SDLC control register 2. The reset  
state of AMV is unknown (indicated by question marks) and must be initialized before enabling the  
SDLC. Note that SDCR2 may be written while the SDLC is enabled to allow the address match  
value to be changed during active receive operation.  
Address: 0h 8002 0068  
SDCR2  
Read/Write  
Bit  
7
6
5
?
4
?
3
?
2
1
0
?
AMV  
Reset  
?
?
?
?
Bit  
7..0  
Name  
AMV  
Description  
Address match value.  
The 8-bit value used by receiver logic to compare to address of incoming frames. If  
address matches, store frame address, control, and data in receive FIFO; if address  
does not match, ignore frame and search for next flag.  
Note: An address of 0hFF (all ones) in the incoming frame automatically generates a  
match (AMV is ignored).  
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Peripheral Control Module  
11.9.6  
SDLC Control Registers 3 and 4  
SDLC control register 3 (SDCR3) contains the upper 4 bits and SDLC control register 4 (SDCR4)  
the lower 8 bits of the baud rate divisor field.  
11.9.6.1  
Baud Rate Divisor (BRD)  
The 12-bit baud rate divisor (BRD) field is used to select the baud or bit rate of the SDLC. A total  
of 4096 different baud rates can be selected, ranging from a minimum of 56.24 bps to a maximum  
of 230.4 Kbps. The baud rate generator uses the 3.6864-MHz clock generated by the on-chip PLL  
and first divides it by the programmable baud rate using BRD. The resultant clock (called the  
sample clock) is then divided by 16 to generate the bit clock. The receive baud clock is  
synchronized with the data steam each time a transition is detected on the receive data line at a bit’s  
boundary. The resultant baud rate given a specific BRD value, or required BRD value given a  
desired baud rate, can be calculated using the following two respective equations, where BRD is  
the decimal equivalent of the unsigned binary value programmed within the bit field:  
6
3.6864×10  
BaudRate = ---------------------------------------  
16x(BRD + 1)  
6
3.6864×10  
BRD = ---------------------------------------- 1  
16
x
BaudRate  
The following tables show the bit locations corresponding to the baud rate divisor field that is split  
between two 8-bit registers. The upper 4 bits of BRD reside within SDCR3 and the lower 8 bits  
reside within SDCR4. The SDLC must be disabled (SUS=RXE=TXE=0) whenever these registers  
are written. Note that writes to reserved bits are ignored and reads return zeros; question marks  
indicate that the values are unknown at reset.  
Address: 0h 8002 006C  
SDCR3  
Read/Write  
Bit  
7
6
5
0
4
0
3
?
2
1
0
?
Reserved  
BRD<11:8>  
Reset  
0
0
?
?
Bit  
3..0  
Name  
Description  
BRD<11:8 Baud rate divisor.  
>
Encoded value (from 0 to 4096). Used to generate the baud rate of the SDLC.  
6
Baud Rate = 3.6864x10 /(16x(BRD+1)), where BRD is a decimal value.  
7..4  
Reserved.  
Address: 0h 8002 0070  
SDCR4  
Read/Write  
Bit  
Reset  
7
6
5
?
4
3
2
?
1
0
?
BRD<7:0>  
?
?
?
?
?
Bit  
7..0  
Name  
Description  
BRD<7:0>  
Baud rate divisor.  
Encoded value (from 0 to 4096). Used to generate the baud rate of the SDLC.  
6
Baud Rate = 3.6864x10 /(16x(BRD+1)), where BRD is a decimal value.  
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Peripheral Control Module  
11.9.7  
SDLC Data Register  
The SDLC data register (SDDR) is an 8-bit register corresponding to both the top and bottom  
entries of the transmit and receive FIFOs, respectively.  
When SDDR is read, the lower 8 bits of the bottom entry of the 11-bit receive FIFO is accessed. As  
data enters the top of the receive FIFO, bits 8..10 are used as tags to indicate various conditions that  
occur during reception of each piece of data. The tag bits are transferred down the FIFO along with  
the data byte that encountered the condition. When data reaches the bottom, bit 8 of the bottom  
FIFO entry is automatically transferred to the end of frame (EOF) flag, bit 9 to the CRC error  
(CRE) flag, and bit 10 to the receiver overrun (ROR) flag, all within SDLC status register 1. The  
user can read these flags to determine if the value at the bottom of the FIFO represents the last byte  
within the packet and/or encountered an error during reception. After checking the flags, the FIFO  
value can then be read, which causes the data in the next location of the receive FIFO to  
automatically transfer down to the bottom entry and its EOF/CRE/ROR bits to be transferred to the  
status register.  
The end/error in FIFO (EIF) status bit is set within status register 0 whenever one or more of the  
tag bits (8..10) are set within any of the bottom four entries of the receive FIFO and is cleared when  
no error bits are set in the bottom four entries of the FIFO. When EIF is set, an interrupt is  
generated and receive FIFO DMA requests are disabled so that the user can manually empty FIFO,  
always checking the end of frame, CRC error, and overrun error flags in status register 1 first  
before removing each data value from the FIFO. After each entry is removed, the user should  
check the EIF bit to see if any errors remain, and repeat the procedure until all errors are flushed  
from the FIFO. Once EIF is cleared, servicing of the receive FIFO by the DMA controller is  
automatically reenabled.  
When SDDR is written, the topmost entry of the 8-bit transmit FIFO is accessed. After a write, data  
is automatically transferred down to the lowest location within the transmit FIFO, which does not  
already contain valid data. Data is removed from the bottom of the FIFO one piece at a time by the  
transmit logic, is loaded into the transmit serial shifter, and is then serially shifted out onto the  
TXD1 pin at the programmed baud rate.  
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Peripheral Control Module  
The following table shows the bit locations corresponding to the data field and end-of-frame bit as  
well as the cyclic redundancy check and receiver overrun error bits within the SDLC data register.  
Note that both FIFOs are cleared when the SA-1100 is reset, the transmit FIFO is cleared when  
writing TXE=0, and the receive FIFO is cleared when writing RXE=0.  
Address: 0h 8002 0078  
SDDR  
Read/Write  
Bit  
10  
ROR  
0
9
CRE  
0
8
EOF  
0
7
0
6
0
5
4
3
2
1
0
0
Bottom of Receive FIFO Data  
Reset  
0
0
0
0
0
Read Access  
Note: ROR, CRE, EOF are not read, but rather are transferred to corresponding status bits in SDSR1  
each time a new data value is transferred to SDDR.  
Bit  
7
0
6
0
5
4
3
2
1
0
0
0
Top of Transmit FIFO Data  
Reset  
0
0
0
0
Write Access  
Bit  
7..0  
Name  
DATA  
Description  
Top/bottom of transmit/receive FIFO data.  
Read – Bottom of receive FIFO.  
Write – Top of transmit FIFO.  
8
EOF  
End of frame.  
0 – The last byte of the frame has not been encountered.  
1– The data value at the bottom of the receive FIFO represents the last byte of the frame.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 8 from the  
last FIFO entry is transferred to the EOF bit in SDSR1.  
9
CRE  
CRC error.  
0 – CRC not encountered yet, or the CRC value calculated on the incoming data  
matched the received CRC value.  
1 – The CRC value calculated on the incoming data did not match the received CRC  
value.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 9 from the  
last FIFO entry is transferred to the CRE bit in SDSR1.  
10  
ROR  
Receiver overrun.  
0 – No receiver overrun has been detected.  
1 – Receive logic attempted to place data into receive FIFO while it was full; one or more  
data values after the data value at the bottom of the receive FIFO were lost.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 10 from the  
last FIFO entry is transferred to the ROR bit in SDSR1.  
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11.9.8  
SDLC Status Register 0  
SDLC status register 0 (SDSR0) contains bits that signal the transmit FIFO service request, receive  
FIFO service request, receiver abort, transmit FIFO underrun, and the end/error in receive FIFO  
condition. Each of these hardware-detected events signal an interrupt request to the interrupt controller.  
A bit that can cause an interrupt signals the interrupt request as long as the bit is set. Once the bit is  
cleared, the interrupt is cleared. Read/write bits are called status bits; read-only bits are called flags.  
Status bits are referred to as “sticky” (once set by hardware, must be cleared by software). Writing  
a one to a sticky status bit clears it; writing a zero has no effect. Read-only flags are set and cleared  
by hardware; writes have no effect. Additionally, some bits that cause interrupts have  
corresponding enable/mask bits in the control registers and are indicated in the following section  
headings. Note that the user has the ability to mask all SDLC interrupts by clearing bit 14 within  
the interrupt controller mask register (ICMR). See the Section 9.2, “Interrupt Controller” on  
11.9.8.1  
End/Error in FIFO Status (EIF) (read-only, nonmaskable interrupt)  
The end/error in FIFO flag (EIF) is a read-only bit that is set when any tag bits (8 through 10) are set  
within the bottom four entries of the receive FIFO and is cleared when no error bits are set within the  
bottom four entries of the FIFO. When EIF is set, an interrupt is signalled and DMA requests to  
empty the receive FIFO are disabled until EIF is cleared. To discover which FIFO entry contains the  
end of frame or an error condition, the user should check the state of the EOF, CRE, and ROR bits and  
read the corresponding value from the SDDR. This procedure should be repeated until EIF is cleared  
because set tag bits that are present within any of the four lowest entries in the receive FIFO can set  
EIF. Once all set tags bits are cleared from the bottom half of the receive FIFO, EIF is automatically  
cleared, which in turn, clears the interrupt and reenables the receive FIFO DMA request.  
11.9.8.2  
Transmit Underrun Status (TUR) (read/write, maskable interrupt)  
The transmit underrun status bit (TUR) is set when the transmit logic attempts to fetch data from the  
transmit FIFO after it has been completely emptied. When an underrun occurs, the transmitter takes  
one of two actions. When the transmit underrun select bit is clear (TUS=0), the transmitter ends the  
frame by shifting out the CRC that is calculated continuously on outgoing data, followed by a flag.  
When TUS=1, the transmitter is forced to transmit an abort and continues to transmit ones until valid  
data is again available within the FIFO. Once data resides within the bottom entry of the transmit  
FIFO, a new data frame is initiated by transmitting a start flag followed by the transmission of data  
from the FIFO. When the TUR bit is set, an interrupt request is made unless it is masked. When  
TUS=0, the interrupt is masked; when TUS=1 it is enabled. Note that underruns are not generated  
when the SDLC transmitter is first enabled and is in the idle state (continuously transmits flags).  
11.9.8.3  
Receiver Abort Status (RAB) (read/write, maskable interrupt)  
The receiver abort status bit (RAB) is set for three different cases:  
when an abort is detected during receipt of an incoming frame  
if the receive carrier is lost during active operation  
if the stop flag is not received on a byte boundary.  
An abort is signalled when seven or more consecutive ones are detected on the RXD1 pin. An abort  
is also signalled if the receive pin is held high or low for more than six bit periods, which indicates  
a loss of carrier. It is also generated when the end flag is received and it is not on a byte boundary,  
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Peripheral Control Module  
which indicates that the address, control, and data fields did not add up to an even multiple of 8  
bits. When an abort is received, the current data byte within the serial shifter is discarded, the least  
recent byte (the oldest of the two bytes) of data in the temporary FIFO is moved to the receive  
FIFO (the other byte is discarded), and the EOF tag is set in the FIFO entry that corresponds to the  
last piece of data that was received before the frame was aborted. The receiver then enters hunt  
mode, searching for a flag. When the RAB bit is set, an interrupt request is made unless the  
receiver abort enable (RAE) bit is cleared.  
11.9.8.4  
Transmit FIFO Service Request Flag (TFS) (read-only, maskable  
interrupt)  
The transmit FIFO service request flag (TFS) is a read-only bit that is set when the transmit FIFO is  
nearly empty and requires service to prevent an underrun. TFS is set whenever the transmit FIFO  
has four or fewer entries of valid data (half-full or less), and is cleared when it has five or more  
entries of valid data. When the TFS bit is set, an interrupt request is made unless the transmit FIFO  
interrupt request enable (TIE) bit is cleared. The state of TFS is also sent to the DMA controller,  
and can be used to signal a DMA service request. Note that TIM has no effect on the generation of  
the DMA service request. After the DMA or CPU fills the FIFO such that five or more locations  
are filled within the transmit FIFO, the TFS flag (and the service request and/or interrupt) is  
automatically cleared.  
11.9.8.5  
Receive FIFO Service Request Flag (RFS) (read-only, maskable  
interrupt)  
The receive FIFO service request flag (RFS) is a read-only bit that is set when the receive FIFO is  
nearly filled and requires service to prevent an overrun. The amount of data that causes RFS to be  
set is nondeterministic. However, the range in which RFS will be set is guaranteed. RFS is set at  
some point when the receive FIFO is one- to two-thirds full (or more). The UART’s FIFOs are  
self-timed to reduce cost and save power. As a result, the depth at which the receive FIFO service  
request is generated is variable. This is the reason the receive FIFO is twelve entries deep instead of  
eight like the transmit FIFO. At which entry in the FIFO the request is actually triggered is  
dependent on IC process, operating temperature, and so on. The receive FIFO is designed to signal  
the RFS bit to be set when it contains eight entries of valid data. However, because of the  
variability of the self-timed logic, RFS may also be set when seven, six, or five entries of valid data  
are present within the FIFO. Likewise, under normal circumstances, RFS is cleared when the  
receive FIFO has seven remaining entries of valid data. However, again due to variations, RFS may  
be cleared when six or five entries of data remain.  
When the RFS bit is set, a DMA service request is made. An interrupt request is also made unless  
the receive FIFO interrupt request enable (RIE) bit is cleared. Even though more than four entries  
of data may exist within the receive FIFO, the user must configure the DMA burst size to four  
words. If programmed I/O is used to service the receive FIFO, a maximum of 4 words may be  
removed without checking if data is valid. After this point, the receive FIFO not empty (RNE) flag  
must be polled before each read to see if more data remains. After the DMA or CPU empties the  
FIFO such that five or more empty locations are available within the receive FIFO, the RFS flag (as  
well as the DMA and interrupt request) is automatically cleared.  
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Peripheral Control Module  
The following table shows the bit locations corresponding to the status and flag bits within SDLC  
status register 0. Note that the reset state of all writable status bits is unknown (indicated by  
question marks) and must be cleared (by writing a one to them) before enabling the SDLC. Also  
note that writes to reserved bits are ignored and reads return zeros.  
Address: 0h 8002 0080  
SDSR0  
Read/Write & Read-Only  
Bit  
7
6
Reserved  
0
5
0
4
RFS  
0
3
TFS  
0
2
RAB  
?
1
TUR  
?
0
EIF  
?
Reset  
0
Bit  
Name  
EIF  
Description  
0
Error in FIFO (read-only).  
0 – Bits 8..10 are not set within any of the four bottom entries of the receive FIFO;  
receive FIFO DMA service requests are enabled.  
1 – One or more tag bits (8..10) are set within one or more of the bottom four entries of  
the receive FIFO; request interrupt, disable receive FIFO DMA service requests.  
1
2
TUR  
RAB  
Transmit FIFO underrun.  
0 –Transmit FIFO has not experienced an underrun.  
1 – Transmit logic attempted to fetch data from transmit FIFO while it was empty;  
interrupt request signalled if not masked (if TUS=1).  
Receiver abort.  
0 – No abort has been detected for the incoming frame.  
1 – Abort detected during receipt of incoming frame, seven or more ones detected on  
receive pin, EOF bit set in receive FIFO next to last piece of “good” data received before  
the abort, interrupt requested if it is enabled (if RAE=1).  
3
4
TFS  
Transmit FIFO service request (read-only).  
0 – Transmit FIFO is more than half-full (five or more entries filled) or transmitter  
disabled.  
1 – Transmit FIFO is half-full or less (four or fewer entries filled) and transmitter operation  
is enabled. DMA service request signalled, interrupt request signalled if it is enabled (if  
TIE=1).  
RFS  
Receive FIFO service request (read-only).  
0 – Receive FIFO contains seven or fewer entries of data or receiver disabled.  
1 – Receive FIFO is one- to two-thirds full (contains 5, 6, 7, or 8 entries of data) or more,  
receiver operation is enabled, DMA service request signalled, and interrupt request  
signalled if it is enabled (if RIE=1).  
7..5  
Reserved.  
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11.9.9  
SDLC Status Register 1  
SDLC status register 1 (SDSR1) contains flags and status bits that indicate when the receiver is  
synchronized, the transmitter is active, that the transmit FIFO is not full, that the receive FIFO is  
not empty, a transition has been detected on the receive line, and when an end of frame, CRC error,  
or underrun error has occurred. All bits within SDSR1 are noninterruptible.  
11.9.9.1  
11.9.9.2  
11.9.9.3  
Receiver Synchronized Flag (RSY) (read-only, noninterruptible)  
The receiver synchronized (RSY) flag is a read-only bit that is set when the receiver is synchronized  
with the incoming data stream and is cleared when the receiver logic is in hunt mode (looking for a  
flag to achieve bit and frame synchronization) or the receiver is disabled (RXE=0). This bit does not  
request an interrupt.  
Transmitter Busy Flag (TBY) (read-only, noninterruptible)  
The transmitter busy (TBY) flag is a read-only bit that is set when the transmitter is actively  
transmitting a frame (address, control, data, CRC, start, or stop flag) or an abort, and is cleared when  
the transmitter is idle (transmitting flags that are not part of a frame) or the transmitter is disabled  
(TXE=0). This bit does not request an interrupt.  
Receive FIFO Not Empty Flag (RNE) (read-only, noninterruptible)  
The receive FIFO not empty flag (RNE) is a read-only bit that is set whenever the receive FIFO  
contains one or more bytes of valid data and is cleared when it no longer contains any valid data. This  
bit can be polled when using programmed I/O to remove remaining bytes of data from the receive  
FIFO because DMA service and CPU interrupt requests are made only when 8, 7, 6, or 5 bytes reside  
within the FIFO. Data remains after each service request as well as at the end of a frame. This bit does  
not request an interrupt.  
11.9.9.4  
Transmit FIFO Not Full Flag (TNF) (read-only, noninterruptible)  
The transmit FIFO not full flag (TNF) is a read-only bit that is set whenever the transmit FIFO  
contains one or more entries that do not contain valid data and is cleared when the FIFO is  
completely full. This bit can be polled when using programmed I/O to fill the transmit FIFO over  
its halfway mark. This bit does not request an interrupt.  
11.9.9.5  
11.9.9.6  
Receive Transition Detect Status (RTD) (read/write, noninterruptible)  
The receive transition detect (RTD) status bit is set whenever the receiver is enabled (RXE=1) and a  
transition is detected on the RXD1 pin (either rising or falling). This bit does not request an interrupt.  
End of Frame Flag (EOF) (read-only, noninterruptible)  
The end of frame flag (EOF) is set when the last byte of data within a frame (including aborted  
frames) resides within the bottom entry of the receive FIFO.  
The receive FIFO contains three tag bits (8, 9, and 10) that are not directly readable. The 8th bit is  
set at the top of the FIFO whenever the last byte within a frame is moved from the receive serial  
shifter to the top of the receive FIFO. This tag travels along with the last data value as it moves  
down the FIFO. Each time a data value is transferred to the bottom of the FIFO (caused by a read of  
the previous value), the state of the tag bit is moved from the FIFO to the EOF bit in the status  
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Peripheral Control Module  
register. After the error in FIFO (EIF) status bit is set, the user should always read SDSR1 first to  
check EOF before reading the data value from SDDR because EOF corresponds to the current data  
byte at the bottom of the receive FIFO and is updated each time data is removed from the FIFO.  
11.9.9.7  
CRC Error Status (CRE) (read-only, noninterruptible)  
The CRC error flag (CRE) is set when the CRC value calculated by the receive logic does not  
match the CRC value contained within the incoming serial data stream.  
The receive FIFO contains 3 tag bits (8, 9, and 10) that are not directly readable. Whenever a CRC  
error is detected, the 9th bit is set within the top entry of the receive FIFO, corresponding to the last  
byte of data within the frame. This tag travels along with the last piece of data from the frame as it  
moves down the FIFO. Each time a data value is transferred to the bottom of the FIFO (caused by a  
read of the previous value), the state of the tag bit is moved from the FIFO to the CRE bit in the  
status register, indicating whether or not the frame has encountered a CRC error. After the error in  
the FIFO (EIF) status bit is set, the user should always read SDSR1 first to check CRE before  
reading the data value from SDDR because CRE corresponds to the current data byte at the bottom  
of the receive FIFO and is updated each time data is removed from the FIFO.  
11.9.9.8  
Receiver Overrun Status (ROR) (read-only, noninterruptible)  
The receiver overrun flag (ROR) is set when the receive logic attempts to place data into the  
receive FIFO after it has been completely filled.  
The receive FIFO contains 3 tag bits (8, 9, and 10) that are not directly readable. The 10th bit is set  
within the top entry of the receive FIFO whenever an overrun occurs. This tag travels along with  
the last “good” data value before the overflow occurred as it moves down the FIFO. Each time a  
data value is transferred to the bottom of the FIFO (caused by a read of the previous value), the  
state of the tag bit is moved from the FIFO to the ROR bit in the status register, indicating that the  
next value in the FIFO is the last “good” piece of data before the overflow occurred. After the error  
in the FIFO (EIF) status bit is set, the user should always read SDSR1 first to check CRE before  
reading the data value from SDDR because CRE corresponds to the current data byte at the bottom  
of the receive FIFO and is updated each time data is removed from the FIFO.  
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Peripheral Control Module  
The following table shows the location of the flag and status bits within SDLC status register 1.  
The bits within this register do not produce interrupt requests. Note that the reset value of RTD is  
unknown (indicated by question marks) and must be cleared if set following a reset of the  
SA-1100. The remainder of SDSR1 is read-only (writes are ignored).  
.
Address: 0h 8002 0084  
SDSR1  
Read/Write & Read-Only  
Bit  
7
ROR  
0
6
CRE  
0
5
EOF  
0
4
3
TNF  
1
2
RNE  
0
1
TBY  
0
0
RSY  
0
RTD  
?
Reset  
Bit  
Name  
RSY  
Description  
0
Receiver synchronized flag (read-only).  
0 – Receiver is in hunt mode or is disabled.  
1 – Receiver logic is synchronized with the incoming data (no interrupt generated).  
1
TBY  
Transmitter busy flag (read-only).  
0 – Transmitter is idle (continuous flags) or disabled.  
1– Transmit logic is currently transmitting a frame (address, control, data, CRC, or  
start/stop flag) or an abort (no interrupt generated).  
2
3
RNE  
TNF  
Receive FIFO not empty (read-only).  
0 – Receive FIFO is empty.  
1 – Receive FIFO is not empty (no interrupt generated).  
Transmit FIFO not full (read-only).  
0 – Transmit FIFO is full.  
1 – Transmit FIFO is not full (no interrupt generated).  
4
5
RTD  
EOF  
Receive transition detect.  
0 – No transition detected on RXD1 pin since the last time software cleared this bit.  
1 – Rising and/or falling edge detected on RXD1 pin (no interrupt generated).  
End of frame (read-only).  
0 – Current frame has not completed.  
1 – The value at the bottom of the receive FIFO is the last byte of data within the frame.  
6
7
CRE  
ROR  
CRC error (read-only).  
0 – No CRC check errors encountered in the receipt of data.  
1 – CRC calculated on the incoming data does not match CRC value contained within  
the received frame.  
Receive FIFO overrun (read-only).  
0 – Receive FIFO has not experienced an overrun.  
1 – Receive logic attempted to place data into receive FIFO while it was full; the next  
data value in the FIFO is the last piece of “good” data before the FIFO was overrun.  
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11.9.10 UART Register Locations  
Table 11-14 shows the registers associated with the UART and the physical addresses used to  
of the programming and operation of the UART (serial port 1’s UART is identical to serial port 3’s  
UART).  
Table 11-14. UART Control, Data, and Status Register Locations  
Address  
0h 8001 0000  
Name  
UTCR0  
Description  
UART control register 0  
0h 8001 0004  
0h 8001 0008  
0h 8001 000C  
0h 8001 0010  
0h 8001 0014  
0h 8001 0018  
0h 8001 001C  
0h 8001 0020  
UTCR1  
UTCR2  
UTCR3  
UART control register 1  
UART control register 2  
UART control register 3  
Reserved  
UTDR  
UART data register  
Reserved  
UTSR0  
UTSR1  
UART status register 0  
UART status register 1  
0h 8001 0024 –  
0h 8001 005C  
Reserved  
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11.9.11 SDLC Register Locations  
Table 11-15 shows the registers associated with the SDLC and the physical addresses used to  
access them.  
Table 11-15. SDLC Control, Data, and Status Register Locations  
Address  
Name  
SDCR0  
Description  
SDLC control register 0  
0h 8002 0060  
0h 8002 0064  
0h 8002 0068  
0h 8002 006C  
0h 8002 0070  
0h 8002 0074  
0h 8002 0078  
0h 8002 007C  
0h 8002 0080  
0h 8002 0084  
SDCR1  
SDCR2  
SDCR3  
SDCR4  
SDLC control register 1  
SDLC control register 2  
SDLC control register 3  
SDLC control register 4  
Reserved  
SDDR  
SDLC data register  
Reserved  
SDSR0  
SDSR1  
SDLC status register 0  
SDLC status register 1  
0h 8002 0088 –  
0h 8002 FFFF  
Reserved  
11.10  
Serial Port 2 – Infrared Communications Port (ICP)  
The infrared communications port (ICP) operates at half-duplex and provides direct connection to  
commercially available Infrared Data Association (IrDA) compliant LED transceivers. The ICP  
supports both the original IrDA standard with speeds up to 115.2 Kbps as well as the newer  
4-Mbps standard. Both standards use different bit encoding techniques and serial packet formats.  
Low-speed IrDA transmission uses the Hewlett-Packard Serial Infrared standard (HP-SIR) for bit  
encoding and a universal asynchronous receiver-transmitter (UART) as the serial engine;  
high-speed uses four-position pulse modulation (4PPM) and a specialized serial packet protocol  
developed expressly for IrDA transmission. To support these two standards, the ICP contains two  
separate blocks, each comprised of a bit encoder/decoder and serial-to-parallel data engine. The  
engine within the ICP that implements the special 4-Mbps protocol is called the high-speed serial  
to parallel (HSSP) receiver-transmitter. Only one of the two standards can be enabled at a time (the  
user cannot enable low-speed transmit and high-speed receive at the same time). To support a  
variety of IrDA transceivers, both the transmit and receive data pins can be individually configured  
to communicate either using normal or inverted data. Additionally, if IrDA transmission is not  
needed, the ICP’s UART can be enabled while disabling the HP-SIR bit encoder for use as a  
general-purpose serial port.  
Note: Programming and operation of serial port 2’s UART is identical to serial port 3. See Section 11.11,  
“Serial Port 3 - UART” on page 11-128 for a complete description of using the ICP for low-speed  
IrDA operation.  
The external pins dedicated to the ICP are TXD2 and RXD2. If serial transmission is not required  
and the ICP is disabled, control of these pins is given to the peripheral pin control (PPC) unit for  
use as general-purpose input/output pins (noninterruptible). See Section 11.13, “Peripheral Pin  
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11.10.1 Low-Speed ICP Operation  
Following reset, both the UART and HSSP are disabled, which causes the peripheral pin controller  
(PPC) to assume control of the port’s pins. Reset causes the PPC to configure all of the peripheral  
pins as inputs, including serial port 2’s transmit (TXD2) and receive (RXD2) pins. Reset also  
causes the UART’s transmit and receive FIFOs to be flushed (all entries invalidated). Before  
enabling the ICP for low-speed operation, the user must first clear any writable or “sticky” status  
bits, which are set by writing a one to each bit. Next, the desired mode of operation is programmed  
in the control registers. At this point the user may “prime” the UART’s transmit FIFO by writing up  
to eight values, or the FIFO can remain empty and either programmed I/O or the DMA can be used  
to service it after the ICP is enabled. Once the ICP is enabled, transmission/reception of data can  
begin on the transmit (TXD2) and receive (RXD2) pins.  
For low-speed operation, all serial data that is transferred between the TXD2/RXD2 pins and the  
ICP’s UART is modulated/demodulated according to the HP-SIR IrDA standard. The IrDA  
standard also specifies the frame format that must be used by the UART.  
*
11.10.1.1 HP-SIR Modulation  
Hewlett-Packard Serial Infrared* (SIR) modulation is used for low-speed transmission up to  
115.2 Kbps. Logic zero is represented by a pulse of light that is either 3/16 of the bit time wide, or  
1.6 µs wide (1.6 µs is 3/16 of the bit time for the highest bit rate of 115.2 Kbps). The rising edge of  
the pulse corresponds to the start of the zero bit time. Logic one is represented by the absence of  
light pulses. Figure 11-24 shows an example of HP-SIR modulation of the byte, 8’b01011001.  
Note that the byte is transmitted starting with the LSB first.  
Figure 11-24. HP-SIR Modulation Example  
LSB  
1
MSB  
0
Bit  
Value  
0
0
1
1
0
1
Digital  
Data  
3/16 of the Bit Time  
HP-SIR*  
Data  
11.10.1.2  
UART Frame Format  
For transmission rates up to 115.2 Kbps, the ICP’s UART is used. The user must program it to  
produce a frame that produces 8 bits of data, one stop bit, and no parity, as shown in Figure 11-25.  
Note that PE=1, SBS=1, DSS=0, SCE=1, BRK=1, RXE=0, TXE=0, and BRD=0x000 are illegal  
programming modes for IrDA operation and will produce unpredictable results. See Section 11.11,  
“Serial Port 3 - UART” on page 11-128 for a complete description of how to program and operate  
the ICP’s UART.  
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Figure 11-25. UART Frame Format for IrDA Transmission (<= 115.2 Kbps)  
Start Bit  
Data<7>  
Data<6>  
Data<5>  
Data<4>  
Data<3>  
Data<2>  
Data<1>  
Data<0>  
Stop Bit  
UTCR0-2 Programming:  
PE=0  
DSS = 1  
SCE = 0  
RCE = don’t care  
TCE = don’t care  
RXE = 1  
TXE = 1  
BRK = 0  
RIE = 0 or 1  
TIE = 0 or 1  
OES = don’t care  
SBS = 0  
BRD = 0x001 to  
0xFFF  
11.10.2 High-Speed ICP Operation  
Before enabling the ICP for high-speed operation, the user must first clear any writable or “sticky”  
status bits that are set by writing a one to each bit. Next, the desired mode of operation is  
programmed in the control registers. At this point the user can “prime” the HSSP’s transmit FIFO  
by writing up to 16 values, or the FIFO can remain empty and either programmed I/O or the DMA  
can be used to service it after the HSSP is enabled. Once the HSSP is enabled,  
transmission/reception of data can begin on the transmit (TXD2) and receive (RXD2) pins.  
For high-speed operation, all serial data, which is transferred between the TXD2/RXD2 pins and  
the ICP’s HSSP, is modulated/demodulated according to the 4PPM IrDA standard. Additionally,  
the HSSP uses a frame format that is very similar to the SDLC’s. For high-speed transmission, both  
the modulation technique and the HSSP’s frame format are discussed in the following sections.  
11.10.2.1 4PPM Modulation  
Four-position pulse modulation (4PPM) is used for the high-speed transmission rate of 4.0 Mbps.  
Two data bits are encoded at a time by placing a single 125 ns light pulse within one of four  
timeslots. The four timeslots are collectively termed a “chip.” Bytes are encoded one at a time.  
They are divided into four individual nibbles (2-bit pairings) and the least significant nibble is  
transmitted first. Figure 11-26 shows the 4PPM encoding for the four possible 2-bit combinations  
and Figure 11-27 shows an example of 4PPM modulation of the byte 8’b10110001 that is  
constructed using four chips. Note that bits within each nibble are not reordered, but nibble 0 (least  
significant) is transmitted first, ending with nibble 3 (most significant).  
Figure 11-26. 4PPM Modulation Encodings  
Chip  
Timeslots  
1
2
3
4
Data = 00  
Data = 01  
Data = 10  
Data = 11  
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Figure 11-27. 4PPM Modulation Example  
Nibble 3  
1
Nibble 2  
1
Nibble 1  
0
Nibble 0  
0
Original  
0
1
1
0
0
1
1
0
Byte Order  
Reordered  
Nibbles  
0
0
1
1
Nibble 0  
Nibble 1  
Nibble 2  
Nibble 3  
Chips  
1
3
4
2
Timeslots  
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
125ns  
4PPM  
Data  
Receive data sample counter frequency = 6X pulse width; each timeslot sampled on third clock.  
11.10.2.2 HSSP Frame Format  
When the 4-Mbps transmission rate is used, the high-speed serial/parallel (HSSP) interface within  
the ICP is used along with the 4PPM bit encoding. The high-speed frame format shown in  
Figure 11-28 is similar to serial port 1’s SDLC format with several minor modifications: the  
start/stop flags and CRC are twice as long, and instead of one start flag, a preamble and start flag of  
differing lengths are used.  
Figure 11-28. High-Speed Serial Frame Format for IrDA Transmission (4.0 Mbps)  
8180 chips  
max  
(2045 bytes)  
4 chips  
(8 bits)  
4 chips  
(8 bits)  
16 chips  
(32 bits)  
64 chips  
8 chips  
8 chips  
Control  
Preamble  
Start Flag  
Start Flag  
Address  
Data  
CRC-32  
Stop Flag  
(optional)  
|0000|1100|0000|1100|0110|0000|0110|0000|  
|0000|1100|0000|1100|0000|0110|0000|0110|  
|1000|0000|1010|1000|... repeated 16 times  
Stop Flag  
Preamble  
The preamble, start, and stop flags are a mixture of chips that contain either 0, 1, or 2 pulses within  
the four timeslots. Chips with 0 and 2 pulses are used to construct flags because they represent invalid  
data bit pairings (one pulse required per chip to represent one of four bit pairs). The preamble  
contains 16 repeated transmissions of the four chips: 1000 0000 1010 1000; the start flag contains one  
transmission of eight chips: 0000 1100 0000 1100 0110 0000 0110 0000; and the stop flag contains  
one transmission of eight chips: 0000 1100 0000 1100 0000 0110 0000 0110. The address, control,  
data, and CRC-32 use the standard 4PPM chip encoding to represent 2 bits per chip.  
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11.10.2.3 Address Field  
The 8-bit address field is used by a transmitter to target a select group of receivers when multiple  
stations are connected to the same set of serial lines. The address allows up to 255 stations to be  
uniquely addressed (00000000 to 11111110). The global address (11111111) is used to broadcast  
messages to all stations. Serial port 1 contains an 8-bit register, which is used to program a unique  
address for broadcast recognition, as well as a control bit to enable/disable the address match  
function. Note that the address of received frames is stored in the receive FIFO along with normal  
data and that it is transmitted and received starting with its LSB and ending with its MSB.  
11.10.2.4 Control Field  
The IPC control field is 8 bits and is optional (as defined by the user). Serial port 2 does not  
provide any hardware decode support for the control byte, but instead treats all bytes between the  
address and the CRC as data. Note that the control field is transmitted and received starting with its  
LSB and ending with its MSB.  
11.10.2.5 Data Field  
The data field can be any length that is a multiple of 8 bits from 0 to 2045 bytes. The user  
determines the data field length according to the application requirements and transmission  
characteristics of the target system. Usually a length is selected that maximizes the amount of data  
that can be transmitted per frame while allowing the CRC checker to be able to consistently detect  
all errors during transmission. Note that serial port 2 does not contain any hardware that restricts  
the maximum amount of data transmitted or received. It is up to the user to maintain these limits. If  
a data field that is not a multiple of 8 bits is received, an abort is signalled. Also note that each byte  
within the data field is transmitted and received starting with its LSB and ending with its MSB.  
11.10.2.6 CRC Field  
The HSSP uses the established 32-bit cyclic redundancy check (CRC-32) to detect bit errors that  
occur during transmission. A 32-bit CRC is computed using the address, control, and data fields,  
and is included in each frame. A separate CRC generator is implemented in both the transmit and  
receive logic. The transmitter calculates a CRC, and while data is actively transmitted, places the  
inverse of the resultant 32-bit value at the end of each frame before the flag is transmitted. In a  
similar manner, the receiver also calculates a CRC for each received data frame and compares the  
calculated CRC to the expected CRC value contained within the end of each received frame. If the  
calculated value does not match the expected value, an interrupt is signalled. The CRC  
computation logic is preset to all ones before reception or transmission of each frame and the result  
is inverted before it is used for comparison or transmission. Note that unlike the address, control,  
and data fields, the 32-bit inverted CRC value is transmitted and received from least significant  
byte to most significant, and within each byte the least significant nibble or chip is encoded or  
decoded first. The cyclic redundancy checker uses the 32-term polynomial:  
32  
26  
23  
22  
16  
12  
11  
10  
8
7
5
4
2
CRC(x)= (x + x + x + x + x + x + x + x + x + x + x + x + x + x + 1)  
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11.10.2.7 Baud Rate Generation  
The baud rate is derived by dividing down a fixed 48-MHz clock generated by one of the two  
on-chip PLLs by six. The 8-MHz baud (or timeslot) clock for the receive logic is synchronized  
with the 4PPM data stream each time a transition is detected on the receive data line using a digital  
PLL. To encode a 4-Mbps data stream, the required “chip” frequency is 2.0 MHz, with four  
timeslots per chip at a frequency of 8.0 MHz. Receive data is sampled halfway through each  
time-slot period by counting three out of the six 48-MHz clock periods that make up each timeslot  
(see Figure 11-27). The chips are synchronized during preamble reception. The repeating pattern  
(four chips repeated 16 times) is used to identify the first timeslot or beginning of a chip and resets  
the 2-bit time-slot counter logic, such that the 4PPM data is properly decoded.  
11.10.2.8 Receive Operation  
The IrDA standard specifies that all transmission occurs at half-duplex. This restriction forces the  
user to enable one direction at a given time: either the transmit or receive logic, but not both.  
However, the HSSP’s hardware does not impose such a restriction.The user may enable both the  
transmitter and receiver at the same time. Although forbidden by the IrDA standard, this feature is  
particularly useful when using the ICP’s loopback mode, which internally connects the output of  
the transmit serial shifter to the input of the receive serial shifter.  
After the ICP is enabled for 4-Mbps transmission, the receiver logic begins by selecting an  
arbitrary chip boundary, receives four incoming 4PPM chips from the RXD2 pin using a serial  
shifter, and latches and decodes the chips one at a time. If the chips do not decode to the correct  
preamble, the time-slot counter’s clock is forced to skip one 8-MHz period, effectively delaying the  
time-slot count by one. This process is repeated until the preamble is recognized, signifying that  
the time-slot counter is synchronized. The preamble can be repeated as few as 16 times or may be  
continuously repeated to indicate an idle receive line.  
At any time after the transmission of 16 preambles, the start flag can be received. The start flag is  
eight chips long. If any portion of the start flag does not match the standard encoding, the receive  
logic signals a framing error and the receive logic once again begins to look for the frame  
preamble.  
Once the correct start flag is recognized, each subsequent grouping of four chips is decoded into a  
data byte and placed within a 5-byte temporary FIFO, which is used to prevent the CRC from being  
placed within the receive FIFO. When the temporary FIFO is filled, data values are pushed out one  
by one to the receive FIFO. The first data byte of a frame is the address. If receiver address  
matching is enabled, the received address is compared to the address programmed in the address  
match value field in one of the control registers. If the two values are equal or if the incoming  
address contains all ones, all subsequent data bytes, including the address byte, are stored in the  
receive FIFO. If the values do not match, the receiver logic does not store any data in the receive  
FIFO, ignores the remainder of the frame, and begins to search for the next preamble. The second  
data byte of the frame can contain an optional control field as defined by the user and must be  
decoded in software (no hardware support within the HSSP).  
Frames can contain any amount of data in multiples of 8 bits up to a maximum of 2047 bytes  
(including the address and control bytes). The HSSP does not limit frame size; it is the  
responsibility of the user to check that the size of each incoming frame does not exceed the IrDA  
protocol’s maximum allowed frame size.  
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When the receive FIFO is one- to two-thirds full, an interrupt or DMA transfer is signalled. If the  
data is not removed soon enough and the FIFO is completely filled, an overrun error is signalled  
when the receive logic attempts to place additional data into the full FIFO. Once the FIFO is full,  
all subsequent data bytes received are lost while all FIFO contents remain intact.  
If any two sequential chips within the data field do not contain pulses (are 0000), the frame is  
aborted, the least recent or oldest byte within the temporary FIFO is moved to the receive FIFO  
(the remaining four FIFO entries are discarded), the end-of-frame (EOF) tag is set within the same  
FIFO entry where the last “good” byte of data resides, and the receiver logic begins to search for  
the preamble. An abort also occurs if any data chip containing 0011, 1010, 0101, or 1001 occurs  
(invalid chips that do not occur in the stop flag).  
The receive logic continuously searches for the 8-chip stop flag. Once it is recognized, the last byte  
that was placed within the receive FIFO is flagged as the last byte of the frame and the data in the  
temporary FIFO is removed and used as the 32-bit CRC value for the frame. Instead of placing this  
in the receive FIFO, the receive logic compares it to the CRC-32 value, which is continuously  
calculated using the incoming data stream. If they do not match, the last byte that was placed  
within the receive FIFO is also tagged with a CRC error. The CRC value is not placed in the  
receive FIFO.  
If the user disables the HSSP’s receiver during operation, reception of the current data byte is  
stopped immediately, the serial shifter and receive FIFO are cleared, control of the RXD2 pin is  
given to the peripheral pin control (PPC) unit, and all clocks used by the receive logic are  
automatically shut off to conserve power. The user should ensure that the polarity of the RXD2  
input is reprogrammed properly if this pin is to be used as a GPIO input.  
11.10.2.9 Transmit Operation  
Before enabling the HSSP for transmission, the user may either “prime” the transmit FIFO by  
filling it with data or allow service requests to cause the CPU or DMA to fill the FIFO once the  
HSSP is enabled. Once enabled, the transmit logic issues a service request if its FIFO is empty. For  
each frame output, a minimum of 16 preambles are transmitted. If data is not available after the  
sixteenth preamble, additional preambles are output until a byte of valid data resides within the  
bottom of the transmit FIFO. The preambles are then followed by the start flag and then the data  
from the transmit FIFO. Four chips (8 bits) are encoded at a time and then loaded into a serial shift  
register. The contents are shifted out onto the TXD2 pin clocked by the 8-MHz baud clock. Note  
that the preamble, start and stop flags, and CRC value are automatically transmitted and need not  
be placed in the transmit FIFO.  
When the transmit FIFO is emptied halfway, an interrupt and/or DMA service request is signalled.  
If new data is not supplied soon enough, the FIFO is completely emptied, and the transmit logic  
attempts to take additional data from the empty FIFO (one of two actions can be taken as  
programmed by the user). An underrun can either signal the normal completion of a frame or an  
unexpected termination of a frame in progress.  
When normal frame completion is selected and an underrun occurs, the transmit logic transmits the  
32-bit CRC value calculated during the transmission of all data within the frame (including the  
address and control bytes), followed by the stop flag to denote the end of the frame. The transmitter  
then continuously transmits preambles until data is once again available within the FIFO. Once  
data is available, the transmitter begins transmission of the next frame.  
When unexpected frame termination is selected and an underrun occurs, the transmit logic outputs  
an abort and interrupts the CPU. An abort continues to be transmitted until data is once again  
available in the transmit FIFO. The HSSP then transmits 16 preambles, a start flag, and starts the  
new frame. The off-chip receiver can choose to ignore the abort and continue to receive data or  
signal the HSSP to retry transmission of the aborted frame.  
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At the end of each frame transmitted, the HSSP outputs a pulse called the serial infrared interaction  
pulse (SIP). A SIP is required at least every 500 ms to keep slower speed devices (115.2 Kbps and  
slower) from colliding with the higher speed transmission. The SIP simulates a start bit that causes  
all low-speed devices to stay off the bus for at least another 500 ms. Transmission of the SIP pulse  
causes the TXD2 pin to be forced high for a duration of 1.625 µs and low for 7.375 µs (total SIP  
period = 9.0 µs). After the 9.0 µs elapses, the preamble is then transmitted continuously to indicate  
to the off-chip receiver that the HSSP’s transmitter is in the idle state. The preamble continues to be  
transmitted until new data is available within the transmit FIFO, or the HSSP’s transmitter is  
disabled. Note that it is the responsibility of the user to ensure that a frame completes once every  
500 ms such that a SIP pulse is produced, keeping all low-speed devices from interrupting  
transmission. Because most IrDA compatible devices produce a SIP after each frame transmitted,  
the user only needs to ensure that a frame is either transmitted or received by the ICP every 500 ms.  
Note that frame length does not represent a significant portion of the 500 ms timeframe in which a  
SIP must be produced. At 4.0 Mbps, the longest frame allowed is 16,568 bits, which takes just over  
4 ms to transmit. Also note that the HSSP issues a SIP when the transmitter is first enabled to  
ensure all low-speed devices are silenced before transmitting its first frame.  
If the user disables the HSSP’s transmitter during operation, transmission of the current data byte is  
stopped immediately, the serial shifter and transmit FIFO are cleared, control of the TXD2 pin is  
given to the peripheral pin control (PPC) unit, and all clocks used by the transmit logic are  
automatically shut off to conserve power. The user should ensure that the polarity of the TXD2  
output is reprogrammed properly if this pin is to be used as a GPIO output.  
11.10.2.10 Transmit and Receive FIFOs  
To reduce chip size and power consumption, the HSSP’s FIFOs use self-timed logic (they are not  
clocked). Because of process and environmental variations, the depth at which a service request is  
triggered to empty the receive FIFO is variable. This variation spans a maximum of four FIFO  
entries; the receive FIFO service request can be made at four different FIFO depths.To compensate  
for this variability and guarantee that at least eight valid entries of data exist within the FIFO before  
generating a service request, an extra four entries have been added to the receive FIFO ( four  
entries more than the transmit FIFO). The transmit FIFO is 16 entries deep and the receive FIFO is  
20 entries deep. The point at which the receive FIFO service request is triggered spans one fifth  
(four entries) of the 20-entry FIFO. The service request is signalled at a depth from two-fifths full  
to three-fifths full (when the FIFO contains nine, ten, eleven, or twelve entries of data).  
This service request variation applies only to an empty FIFO that is filled (receive FIFO). It does  
not apply to a full FIFO that is emptied (transmit FIFO). The transmit FIFO is guaranteed to signal  
a service request when it has eight or more empty entries and negate the request when the FIFO  
contains nine or more entries that are filled.  
If the DMA is used to service either one or both of the HSSP’s FIFOs, the burst size must be set to  
eight words, even though more than eight entries of data may exist within the receive FIFO. If  
programmed I/O is used to service the FIFOs, a maximum of 8 words may be added to the transmit  
FIFO without checking if more space is available. Likewise, a maximum of 8 words may be  
removed from the receive FIFO without checking if more data is available. After this point, the  
user must poll a set of status bits that indicate if any data remains in the receive FIFO or if space is  
available in the transmit FIFO before emptying or filling the FIFOs any further.  
11.10.2.11 CPU and DMA Register Access Sizes  
Bit positioning, byte ordering, and addressing of the SDLC is described in terms of little endian  
ordering. All ICP (HSSP and UART) registers are 8 bits wide and are located in the least  
significant byte of individual words. The ARM peripheral bus does not support byte or half-word  
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operations. All reads and writes of the ICP by the CPU should be wordwide. Two separate,  
dedicated DMA requests exist for both the transmit and the receive FIFOs. If the DMA controller is  
used to service the transmit and/or receive FIFOs, the user must ensure the DMA is properly  
configured to perform bytewide accesses, using 8 bytes per burst for the HSSP and 4 bytes per  
burst for the UART. See later sections in this chapter for summaries of the ICP’s UART registers  
and HSSP registers.  
11.10.3 UART Register Definition  
The ICP’s UART is the same as serial port 3’s UART except that one additional register exists to  
control HP-SIR modulation for low-speed operation. See Section 11.11, “Serial Port 3 - UART” on  
page 11-128 for a description of the programming and operation of all other features of the ICP’s  
UART. Note that the user must ensure that the UART is programmed to yield the frame format  
shown in Figure 11-25.  
11.10.4 UART Control Register 4  
UART control register 4 (UTCR4) contains two different bit fields that control various functions  
for 115.2-Kbps (low-speed) IrDA transmission.  
11.10.4.1 HP-SIR Enable (HSE)  
The HP-SIR enable (HSE) bit controls whether the HP-SIR bit modulation logic is enabled or  
disabled. When HSE=0, HP-SIR modulation is disabled, and if UART operation is enabled  
(ITR=0), it is used for normal serial transmission (NRZ encoding only) rather than IrDA  
communication. When HSE=1, HP-SIR modulation is enabled for low-speed IrDA  
communication; zeros are represented by pulses that are 3/16 of the programmed bit width, while  
ones are represented by no pulses.  
11.10.4.2 Low-Power Mode (LPM)  
The low-power mode (LPM) bit controls whether the HP-SIR bit modulation logic represents zeros  
using a pulse that is 3/16 of the chosen bit width or a fixed 1.6 µs pulse width. When LPM=0, zeros  
are encoded as a pulse, which is 3/16 of the bit width programmed within the UART’s baud rate  
divisor (BRD) bit field. When LPM=1, the UART’s programmed bit length is ignored and zeros are  
represented by pulses that are 1.6 µs in duration. Programming LPM=1 minimizes the time that the  
off-chip LED transceiver is turned on to the minimum pulse width specified by the IrDA low-speed  
standard, which in turn, minimizes power consumption.  
The following table shows the location of the bits within UART control register 4; question marks  
indicate that the values are unknown at reset. Both bits are reset to zero. Note that the UART must  
be disabled (RXE=TXE=0) when changing the state of either of these two bits. Also note that  
writes to reserved bits are ignored and reads return zeros.  
Address: 0h 8003 0010  
UTCR4  
Read/Write  
Bit  
7
6
5
0
4
0
3
0
2
0
1
LPM  
?
0
HSE  
?
Reserved  
Reset  
0
0
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Bit  
Name  
Description  
0
HSE  
LPM  
HP-SIR enable.  
0 – HP-SIR modulation disabled; ICP functions as normal UART if ITR=0.  
1 – HP-SIR modulation enabled; ICP functions as low-speed IrDA port if ITR=0.  
1
Low-power mode.  
0 – Each zero encoded as a pulse that is 3/16 of the programmed bit time if ITR=0.  
1 – Each zero encoded as a pulse that is 1.6 µs wide if ITR=0.  
7..2  
Reserved.  
11.10.5 HSSP Register Definitions  
There are six registers within the HSSP: three control registers, one data register, and two status  
registers. The control registers are used to select IrDA transmission rate, address match value,  
whether an abort or end of frame occurs when the transmit FIFO underruns, and true or  
complemented transmit and receive data; to enable or disable transmit and receive operation, the  
FIFO interrupt service requests, receive address matching, and loopback mode.  
The data register addresses the top location of the transmit FIFO and bottom location of the receive  
FIFO. When it is read, the receive FIFO is accessed, and when it is written, the transmit FIFO is  
accessed.  
The status registers contain bits that signal CRC, overrun, underrun, framing, and receiver abort  
errors as well as the transmit FIFO service request, receive FIFO service request, and end-of-frame  
conditions. Each of these hardware-detected events signals an interrupt request to the interrupt  
controller. The status registers also contain flags for transmitter busy, receiver synchronized,  
receive FIFO not empty, and transmit FIFO not full (no interrupt generated).  
11.10.6 HSSP Control Register 0  
The HSSP control register 0 (HSCR0) contains eight different bit fields that control various  
functions for 4 Mbps IrDA transmission.  
11.10.6.1 IrDA Transmission Rate (ITR)  
The IrDA transmission rate (ITR) bit is used to select the transmission speed of the ICP. ITR selects  
the correct type of IrDA bit modulation to use (HP-SIR or 4PPM), and enables the correct  
serial-to-parallel engine (UART or HSSP). When ITR=0, the HP-SIR modulator is enabled along  
with serial port 2’s UART. When ITR=1, the 4PPM modulator is enabled as well as the HSSP. Note  
that ITR is the only control bit that affects both the UART and HSSP. Once one of the two speeds is  
selected, all further programming is controlled by the individual units (UART or HSSP).  
11.10.6.2 Loopback Mode (LBM)  
The loopback mode (LBM) bit is used to enable and disable the ability of the HSSP’s transmit and  
receive logic to communicate. When LBM=0, the HSSP operates normally. The transmit and  
receive data paths are independent and communicate via their respective pins. When LBM=1, the  
output of the transmit serial shifter is directly connected to the input of the receive serial shifter  
internally, and control of the TXD2 and RXD2 pins is given to the peripheral pin control (PPC)  
unit. Note that even though the IrDA standard permits only half-duplex operation, the HSSP does  
not restrict the user from transmitting and receiving data at the same time; both are fully  
independent units. This function is essential when using the HSSP in loopback mode.  
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11.10.6.3 Transmit FIFO Underrun Select (TUS)  
The transmit FIFO underrun select (TUS) bit is used both to select what action to take as a result of  
a transmit FIFO underrun as well as mask or enable the transmit FIFO underrun interrupt.  
When TUS=0, transmit FIFO underruns are used to signal the transmit logic that the end of the  
frame has been reached. When the transmit FIFO experiences an underrun, the CRC value, which  
is calculated continuously on outgoing data, is loaded to the serial shifter and transmitted, followed  
by the stop flag and SIP pulse. Also when TUS=0, the transmit FIFO interrupt is masked and the  
state of the transmit FIFO underrun (TUR) status bit is ignored by the interrupt controller.  
When TUS=1, transmit FIFO underruns are used to signal the transmit logic that the end of the  
frame has not yet been reached. When the transmit FIFO experiences an underrun, the CRC value,  
which is calculated continuously on outgoing data, is loaded to the serial shifter and transmitted,  
followed by the stop flag and SIP pulse. Additionally, when TUS=0, the transmit FIFO underrun  
interrupt is masked, causing the state of the transmit FIFO underrun (TUR) status bit to be ignored  
by the interrupt controller. Note that programming TUS=0 does not affect the current state of TUR  
or the transmit FIFO logic’s ability to set and clear TUR; it only blocks the generation of the  
interrupt request.  
When TUS=1, transmit FIFO underruns are used to signal the transmit logic that the end of the  
frame has not yet been reached and that the rate in which data is supplied to the transmit FIFO is  
not sufficient. When the transmit FIFO experiences an underrun, two sequential chips, each  
containing zeros (0000), are output by the transmitter to signal an abort condition; next a SIP pulse  
is output, followed by a minimum of 16 preambles. Preambles continue to be output until data is  
once again available within the transmit FIFO. Additionally, when TUS=1, the transmit FIFO  
underrun interrupt is enabled, and whenever TUR is set (one), an interrupt request is made to the  
interrupt controller. To change the state of TUS during operation, the user should fill the transmit  
FIFO to ensure TUS is not written at the same time that the transmit FIFO underruns.  
TUS is useful for ensuring that frames are not prematurely ended due to an unexpected transmit  
FIFO underrun. At the start of a frame, the user can configure TUS=1 such that any underrun  
signals an abort to the off-chip receiver. Just before the end of the frame, the user can then  
configure TUS=0, allowing the remaining data to be output by the transmit logic. The FIFO then  
underruns, causing the CRC, stop flag, and SIP to be transmitted.  
11.10.6.4 Transmit Enable (TXE)  
The transmit enable (TXE) bit is used to enable and disable HSSP transmit operation. When  
TXE=0, the transmit logic is disabled and its clocks are turned off to conserve power. When  
TXE=1, the HSSP transmitter logic is enabled for IrDA transmission. It is required that the user  
first program all other control bits before setting TXE. If the TXE bit is cleared to zero while the  
HSSP is actively transmitting data, transmission is stopped immediately, all data within the  
transmit FIFO and serial output shifter is cleared, and control of the TXD2 pin is given to the  
peripheral pin control (PPC) unit. When the transmitter is turned on (TXE=01), a SIP pulse is  
transmitted before transmission of data. A SIP pulse is used to prevent slower devices (115.2 Kbps)  
from attempting to take control of infrared transmission. See the previous sections for further  
timing details of the SIP pulse.  
TXE and RXE are the only control bits within the HSSP that are initialized when a hardware reset  
occurs. Clearing TXE to zero ensures the HSSP transmitter is disabled, giving control of the  
transmit pin to the PPC unit that configures TXD1 as an input following a reset of the SA-1100.  
Note that TXE is ignored when ITR=0 (enables UART operation). Also note that even though the  
IrDA standard permits only half-duplex operation, the HSSP does not restrict the user from  
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transmitting and receiving data at the same time; both are fully independent units. This function is  
particularly useful when using the HSSP in loopback mode. See the Section 11.10.6.2, “Loopback  
11.10.6.5 Receive Enable (RXE)  
The receive enable (RXE) bit is used to enable or disable HSSP receive operation. When RXE=0, the  
receive logic is disabled and its clocks are turned off to conserve power. When RXE=1, the HSSP  
receiver logic is enabled for IrDA reception. It is required that the user first program all other control  
bits before setting RXE. If the RXE bit is cleared to zero while the HSSP is actively receiving data,  
reception is stopped immediately, all data within the receive FIFO and serial input shifter is cleared,  
and control of the RXD2 pin is given to the peripheral pin control (PPC) unit. Note that TXE and  
RXE are the only control bits within the HSSP that are initialized when a hardware reset occurs.  
Clearing RXE to zero ensures the HSSP receiver is disabled, giving control of the receive pin to the  
PPC unit, which configures RXD2 as an input following a reset of the SA-1100. Note that RXE is  
ignored when ITR=0, which enables UART operation. Also note that even though the IrDA standard  
permits only half-duplex operation, the HSSP does not restrict the user from transmitting and  
receiving data at the same time; both are fully independent units. This function is particularly useful  
when using the HSSP in loopback mode. See the Section 11.10.6.2, “Loopback Mode (LBM)” on  
11.10.6.6 Receive FIFO Interrupt Enable (RIE)  
The receive FIFO interrupt mask (RIE) bit is used to mask or enable the receive FIFO service  
request interrupt. When RIE=0, the interrupt is masked, and the state of the receive FIFO service  
request (RFS) bit within HSSP status register 0 is ignored by the interrupt controller. When RIE=1,  
the interrupt is enabled, and whenever RFS is set (one), an interrupt request is made to the interrupt  
controller. Note that programming RIE=0 does not affect the current state of RFS or the receive  
FIFO logic’s ability to set and clear RFS; it only blocks the generation of the interrupt request.  
Also note that RIE does not affect generation of the receive FIFO DMA request , which is asserted  
whenever RFS=1.  
11.10.6.7 Transmit FIFO Interrupt Enable (TIE)  
The transmit FIFO interrupt mask (TIE) bit is used to mask or enable the transmit FIFO service  
request interrupt. When TIE=0, the interrupt is masked and the state of the transmit FIFO service  
request (TFS) bit within HSSP status register 0 is ignored by the interrupt controller. When TIE=1,  
the interrupt is enabled, and whenever TFS is set (one), an interrupt request is made to the interrupt  
controller. Note that programming TIE=0 does not affect the current state of TFS or the transmit  
FIFO logic’s ability to set and clear TFS; it only blocks the generation of the interrupt request.  
Also note that TIE does not affect generation of the transmit FIFO DMA request, which is asserted  
whenever TFS=1.  
11.10.6.8 Address Match Enable (AME)  
The address match enable (AME) bit is used to enable or disable the receive logic from comparing  
the address programmed in the address match value (AMV) bit field to the address of all incoming  
frames. When AME=1, data is stored in the receive FIFO only for those frames that have addresses  
that match AMV and for any frame that contains an address containing all ones (11111111),  
denoting a global address. For frames in which the address does not match, the data and CRC are  
ignored and the receiver resumes hunting for a preamble. When AME=0, address values are not  
compared and the data in every frame is stored in the receive FIFO.  
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The following table shows the location of the bits within HSSP control register 0. RXE and TXE  
are the only control bits that are reset to a known state to ensure the HSSP is disabled following a  
reset of the SA-1100. The reset state of all other control bits is unknown (indicated by question  
marks) and must be initialized before enabling the HSSP. Note that the HSSP must be disabled  
(RXE=TXE=0) when changing the state of bits 0 and 1, and bits 2 through 7 may be written while  
the HSSP is enabled to allow various modes to be changed during active operation.  
Address: 0h 8004 0060  
HSCR0  
Read/Write  
Bit  
7
AME  
?
6
TIM  
?
5
RIM  
?
4
3
TXE  
0
2
TUS  
?
1
LBM  
?
0
ITR  
?
RXE  
0
Reset  
Bit  
Name  
ITR  
Description  
0
IrDA transmission rate.  
0 – 115.2 Kbps (selects HP-SIR modulation, enables the ICP’s UART engine).  
1 – 4.0 Mbps (selects 4PPM modulation, enables the ICP’s HSSP engine).  
1
LBM  
TUS  
Loopback mode.  
0 – Normal serial port operation enabled.  
1 – Output of HSSP’s transmit serial shifter is connected to input of receive serial shifter  
internally. Control of TXD2 and RXD2 pins is given to the PPC unit if ITR=1.  
2
3
Transmit FIFO underrun select.  
0 – Transmit FIFO underrun causes CRC, stop flag, and SIP to be transmitted, and  
masks transmit underrun interrupt generation (TUR ignored).  
1 –Transmit FIFO underrun causes an abort to be transmitted, and generates an interrupt  
(state of TUR sent to interrupt controller).  
TXE  
Transmit enable.  
0 – HSSP transmit logic disabled; control of the TXD2 pin is given to the PPC unit if ITR=1.  
1 – HSSP transmit logic enabled if ITR=1.  
Note: A SIP is transmitted immediately after the transmitter is enabled (TXE = 0 1).  
4
5
RXE  
RIE  
Receive enable.  
0 – HSSP receive logic disabled; control of the RXD2 pin is given to the PPC unit if ITR =1.  
1 – HSSP receive logic enabled if ITR=1.  
Receive FIFO interrupt enable.  
0 – Receive FIFO two- or three-fifths full or more condition does not generate an  
interrupt (RFS bit ignored).  
1 – Receive FIFO two- or three-fifths full or more condition generates an interrupt (state  
of RFS sent to interrupt controller).  
6
7
TIE  
Transmit FIFO interrupt enable.  
0 – Transmit FIFO half-full or less condition does not generate an interrupt (TFS bit ignored).  
1 – Transmit FIFO half-full or less condition generates an interrupt (state of TFS sent to  
interrupt controller).  
AME  
Address match enable.  
0 – Disable receiver address match function, store data from all incoming frames in  
receive FIFO.  
1 – Enable receiver address match function; do not FIFO data unless address  
recognized or incoming address contains all ones (0hFF).  
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11.10.7 HSSP Control Register 1  
HSSP control register 1 (HSCR1) contains the 8-bit address match value field that is used by the  
HSSP to selectively receive frames.  
11.10.7.1 Address Match Value (AMV)  
The 8-bit address match value (AMV) field is programmed with an address value that is used to  
selectively store only the data within receive frames that have the same address value. The address  
match enable (AME) bit must be set to enable this function. For incoming frames, which have the  
same address value as the AMV field, the frame’s address, control, and data are stored in the  
receive FIFO. For those that do not, the remainder of the frame is ignored and the receive logic  
switches to hunt mode, looking for the preamble in the incoming data stream. One special address  
exists, which is always matched by the address match logic regardless of the value programmed in  
AMV. When address matching is enabled, whenever a frame is received with an address containing  
all ones (11111111), the value programmed in AMV is ignored and the frame data is automatically  
stored in the receive FIFO. The address value is contained within the first byte of data in a frame  
following the flag. AMV can be written at any time and is used for comparison with the next frame,  
which occurs following its update.  
The following table shows the address match value field within HSSP control register 1. The reset  
state of AMV is unknown (indicated by question marks) and must be initialized before enabling the  
HSSP. Note that HSCR1 may be written while the HSSP is enabled to allow the address match  
value to be changed during active receive operation.  
Address: 0h 8004 0064  
HSCR1  
Read/Write  
Bit  
7
6
5
?
4
?
3
?
2
?
1
0
?
AMV  
Reset  
?
?
?
Bit  
7..0  
Name  
AMV  
Description  
Address match value.  
The 8-bit value used by receiver logic to compare to address of incoming frames. If  
AME=1 and AVM matches the address of the incoming frame, store the frame address,  
control, and data in receive FIFO; if address does not match, ignore the frame and  
search for the next preamble.  
Note: An address of 0hFF (all ones) in the incoming frame automatically generates a  
match (AMV is ignored).  
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11.10.8 HSSP Control Register 2  
The HSSP control register 2 (HSCR2) contains two bit-fields that control the polarity of the  
transmit and receive data pins. Note that unlike the rest of the HSSP’s registers, its bits are located  
in byte 2 of the addressed word (bits 23..16). Word reads or writes should be used to access this  
register. Also note that this register resides within the PPC’s address space.  
11.10.8.1 Transmit Pin Polarity Select (TXP)  
The transmit pin polarity select (TXP) bit is used to select whether data output to the ICP’s transmit  
pin (TXD2) is true or complemented. When TXP=0, data output from the UART (low-speed  
mode), HSSP (high-speed mode), or PPC (GPIO output mode) is inverted first before being output  
to the TXD2 pin. When TXP=1, data output from either the UART, HSSP, or PPC to the TXD2 pin  
is true or noninverted. TXP is initialized to 1 following reset such that output pin data defaults to  
true data.  
Note that TXP affects the TXD2 pin during all modes of operation including HSSP, UART, and  
PCC. The user should ensure that this bit is properly programmed when using serial port 2 for high-  
or low-speed IrDA, normal UART, or GPIO operation. Note that for GPIO mode, the user needs to  
configure TXP only when the pin is to be used as an output (PPDR<14>=1). When used as a GPIO  
input, TXP has no effect on the state of TXD2. See the Peripheral Pin Controller chapter.  
Additionally, the user must ensure that the PPC sleep state direction bit for TXD2 is inverted from  
its normal value, if TXP=0 indicating inverted data. Thus if the user wishes to make TXD2 an  
output in sleep mode, but TXP=0 indicating the output is inverted, the PPC should be programmed  
such that PSDR<14>=1. Likewise, if TXP=0 and the user wishes to make TXD2 an input in sleep  
mode, the PPC should be programmed such that PSDR<14>=0. If TXP=1 indicating true data,  
PSDR should be programmed normally.  
11.10.8.2 Receive Pin Polarity Select (RXP)  
The receive pin polarity select (RXP) bit is used to select whether data input to the ICP’s receive  
pin (RXD2) is viewed by the ICP as true or complemented. When RXP=0, data input from the  
RXD2 pin is first inverted before being sent to either the UART (low-speed mode), HSSP  
(high-speed mode), or PPC (GPIO input mode). When RXP=1, data input from the RXD2 pin is  
treated as true data and is not inverted before being sent to either the UART, HSSP, or PPC. RXP is  
initialized to 1 following reset such that input pin data defaults to true data.  
Note that RXP affects the RXD2 pin during all modes of operation including HSSP, UART, and  
PCC. The user should ensure that this bit is properly programmed when using serial port 2 for high-  
or low-speed IrDA, normal UART, or GPIO operation. Note that for GPIO mode, the user needs to  
configure RXP only when the pin is to be used as an input (PPDR<15>=0). When used as a GPIO  
output, RXP has no effect on the state of RXD2.  
Also note that, unlike the TXP bit, RXP has no effect on the PPC sleep state direction bit for  
RXD2. PSDR<15> should be programmed normally.  
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The following table shows the location of the bits within HSSP control register 2. Both bits are set  
to one to ensure serial port 2’s pins default to normal “true” data operation following a reset of the  
SA-1100. Note that the HSSP and UART must be disabled (RXE=TXE=0) when changing the state  
of these bits. Also note that reads of reserved bits return zero and writes have no effect.  
Address: 0h 9006 0028  
HSCR2  
Read/Write  
Bit  
23  
22  
21  
0
20  
0
19  
18  
TXP  
1
17  
16  
0
Reserved  
RXP  
1
Reserved  
Reset  
0
0
0
Bit  
Name  
Description  
17..16  
Reserved.  
18  
TXP  
RXP  
Transmit pin polarity select.  
0 – Data output from the HSSP, UART, or PPC is first inverted before being output to TXD2.  
1 – Data output from the HSSP, UART, or PPC to TXD2 is true or non-inverted data.  
19  
Receive pin polarity select.  
0 – Data input from RXD2 is first inverted before being used by the HSSP, UART, or PPC.  
1 – Data input from RXD2 to the HSSP, UART, or PPC is true or non-inverted data.  
23..20  
Reserved.  
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11.10.9 HSSP Data Register  
The HSSP data register (HSDR) is an 8-bit register corresponding to both the top and bottom entry  
of the transmit and receive FIFOs, respectively.  
When HSDR is read, the lower 8 bits of the bottom entry of the 11-bit receive FIFO is accessed. As  
data enters the top of the receive FIFO, bits 8 – 10 are used as tags to indicate various conditions  
that occur during reception of each piece of data. The tag bits are transferred down the FIFO along  
with the data byte that encountered the condition. When data reaches the bottom, bit 8 of the  
bottom FIFO entry is automatically transferred to the end-of-frame (EOF) flag, bit 9 to the CRC  
error (CRE) flag, and bit 10 to the receiver overrun (ROR) flag, all within HSSP status register 1.  
The user can read these flags to determine if the value at the bottom of the FIFO represents the last  
byte within the frame or if an error was encountered during reception. After checking the flags, the  
FIFO value can then be read, which causes the data in the next location of the receive FIFO to  
automatically transfer down to the bottom entry and its EOF/CRE/ROR bits to be transferred to the  
status register.  
The end/error in FIFO (EIF) flag is set within status register 0 whenever one or more of the tag bits  
(8 – 10) are set within any of the bottom eight entries of the receive FIFO and is cleared when no  
error bits are set in the bottom eight entries of the FIFO. When EIF is set, an interrupt is generated  
and receive FIFO DMA requests are disabled so that the user can manually empty the FIFO,  
always checking the end-of-frame, CRC error, and overrun error flags in status register 1 first  
before removing each data value from the FIFO. After each entry is removed, the user should  
check the EIF bit to see if any set end or error tag remains, and repeat the procedure until all set  
tags are flushed from the bottom eight entries of the FIFO. Once EIF is cleared, servicing of the  
receive FIFO by the DMA controller is automatically reenabled.  
When HSDR is written, the topmost entry of the 8-bit transmit FIFO is accessed. After a write, data  
is automatically transferred down to the lowest location within the transmit FIFO, which does not  
already contain valid data. Data is removed from the bottom of the FIFO one piece at a time by the  
transmit logic, encoded using the 4PPM modulation technique, loaded into the transmit serial  
shifter, then serially shifted out onto the TXD2 pin.  
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The following table shows the bit locations corresponding to the data field, end-of-frame bit as well  
as the cyclic redundancy check and receiver overrun error bits within the HSSP data register. Note  
that both FIFOs are cleared when the SA-1100 is reset, the transmit FIFO is cleared when TXE=0,  
and the receive FIFO is cleared when RXE=0.  
Address: 0h 8004 006C  
HSDR  
Read/Write  
Bit  
10  
ROR  
0
9
CRE  
0
8
EOF  
0
7
0
6
0
5
4
3
2
1
0
0
Bottom of receive FIFO data  
Reset  
0
0
0
0
0
Read Access  
(Note: ROR, CRE, EOF are not read, but rather transferred to corresponding status bits in the HSSP  
status register 1(HSSR1) each time a new data value is transferred to HSDR).  
Bit  
7
0
6
0
5
4
3
2
1
0
0
0
Top of transmit FIFO data  
Reset  
0
0
0
0
Write Access  
Bit  
7..0  
Name  
DATA  
Description  
Top/bottom of transmit/receive FIFO data.  
Read – Bottom of receive FIFO.  
Write –Top of transmit FIFO.  
8
EOF  
End of frame.  
0 – The last byte of the frame has not been encountered.  
1 – The data value at the bottom of the receive FIFO represents the last byte of the  
frame.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 8 from the  
last FIFO entry is transferred to the EOF bit in HSSR1.  
9
CRE  
CRC error.  
0 – CRC not encountered yet, or the CRC value calculated on the incoming data  
matched the received CRC value.  
1 – The CRC value calculated on the incoming data did not match the received CRC  
value.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 9 from the  
last FIFO entry is transferred to the CRE bit in HSSR1.  
10  
ROR  
Receiver overrun.  
0 – No receiver overrun has been detected.  
1 – Receive logic attempted to place data into receive FIFO while it was full; one or more  
data values after the data value at the bottom of the receive FIFO were lost.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 10 from the  
last FIFO entry is transferred to the ROR bit in HSSR1.  
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11.10.10 HSSP Status Register 0  
HSSP status register 0 (HSSR0) contains bits that signal the transmit FIFO service request, receive  
FIFO service request, receiver abort, transmit FIFO underrun, framing error, and the end/error in  
receive FIFO conditions. Each of these hardware-detected events signal an interrupt request to the  
interrupt controller.  
A bit that can cause an interrupt signals the interrupt request as long as the bit is set. Once the bit is  
cleared, the interrupt is cleared. Read/write bits are called status bits; read-only bits are called flags.  
Status bits are referred to as “sticky” (once set by hardware, must be cleared by software). Writing  
a one to a sticky status bit clears it; writing a zero has no effect. Read-only flags are set and cleared  
by hardware; writes have no effect. Additionally, some bits that cause interrupts have  
corresponding mask bits in the control registers and are indicated in the following sections. Note  
that the user has the ability to mask all HSSP interrupts by clearing bit 16 within the interrupt  
controller mask register (ICMR).  
11.10.10.1 End/Error in FIFO Status (EIF) (read-only, nonmaskable interrupt)  
The end/error in FIFO flag (EIF) is a read-only bit that is set when any tag bits (8 through 10) are  
set within the bottom eight entries of the receive FIFO and is cleared when no tag bits are set within  
the bottom eight entries of the FIFO. When EIF is set, an interrupt is signalled and DMA requests  
to empty the receive FIFO are disabled until EIF is cleared. To discover which FIFO entry contains  
the end-of-frame or an error condition, the user should check the state of the EOF, CRE, and ROR  
bits (described in the following sections), then read the corresponding value from the HSDR. This  
procedure should be repeated until EIF is cleared because set flag bits that are present within any of  
the eight lowest entries in the receive FIFO can set EIF. Once all tags are cleared from the bottom  
eight entries of the receive FIFO, EIF is automatically cleared, which in turn, clears the interrupt  
and reenables receive FIFO DMA requests.  
11.10.10.2 Transmit Underrun Status (TUR) (read/write, maskable interrupt)  
The transmit underrun status bit (TUR) is set when the transmit logic attempts to fetch data from  
the transmit FIFO after it has been completely emptied. When an underrun occurs, the transmitter  
takes one of two actions. When the transmit underrun select bit is clear (TUS=0), the transmitter  
ends the frame by shifting out the CRC that is calculated continuously on outgoing data, followed  
by a stop flag and SIP pulse. When TUS=1, the transmitter is forced to transmit an abort and  
continues to transmit chips containing all zeros (0000) until valid data is again available within the  
FIFO. Once data resides within the bottom entry of the transmit FIFO, a new data frame is initiated  
by transmitting 16 preambles and a start flag followed by the transmission of data from the FIFO.  
When the TUR bit is set, an interrupt request is made unless it is masked. When TUS=0, the  
interrupt is masked; when TUS=1, it is enabled. Note that underruns are not generated when the  
HSSP transmitter is first enabled and is in the idle state (continuously transmits flags).  
11.10.10.3 Receiver Abort Status (RAB) (read/write, nonmaskable interrupt)  
The receiver abort status bit (RAB) is set when an abort is detected during receipt of an incoming  
frame. An abort is signalled when two or more chips that do not contain any pulses (0000) or chips  
containing 0011, 1001, 1010, or 0101(invalid chips not contained within the stop flag) are detected  
after a valid start flag has been detected but before a complete stop flag has been received (an  
incorrect chip in the stop flag generates an abort as well). When an abort is received, the EOF tag is  
set in the FIFO entry that corresponds to the last piece of data received before the frame was  
aborted. The receiver then enters hunt mode, searching for the preamble.  
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Peripheral Control Module  
11.10.10.4 Transmit FIFO Service Request Flag (TFS) (read-only, maskable  
interrupt)  
The transmit FIFO service request flag (TFS) is a read-only bit that is set when the transmit FIFO is  
nearly empty and requires service to prevent an underrun. TFS is set any time the transmit FIFO  
has eight or fewer entries of valid data (half-full or less), and is cleared when it has nine or more  
entries of valid data. When the TFS bit is set, an interrupt request is made unless the transmit FIFO  
interrupt request mask (TIE) bit is cleared. The state of TFS is also sent to the DMA controller, and  
can be used to signal a DMA service request. Note that TIE has no effect on the generation of the  
DMA service request. After the DMA or CPU fills the FIFO, such that eight or more locations are  
filled within the transmit FIFO, the TFS flag (and the service request and/or interrupt) is  
automatically cleared.  
11.10.10.5 Receive FIFO Service Request Flag (RFS) (read-only, maskable  
interrupt)  
The receive FIFO service request flag (RFS) is a read-only bit that is set when the receive FIFO is  
nearly filled and requires service to prevent an overrun. The amount of data that causes RFS to be  
set is nondeterministic. However, the range in which RFS will be set is guaranteed. RFS is set at  
some point when the receive FIFO is two- to three-fifths full (or more). The HSSP’s FIFOs are  
self-timed to reduce cost and save power. As a result, the depth at which the receive FIFO service  
request is generated is variable. This is the reason the receive FIFO is 20 entries deep instead of 16  
like the transmit FIFO. At which entry in the FIFO the request is actually triggered is dependent on  
IC process, operating temperature, and so on. The receive FIFO is designed to signal the RFS bit to  
be set when it contains 12 entries of valid data. However, because of the variability of the  
self-timed logic, RFS may also be set when 11, 10, or 9 entries of valid data are present within the  
FIFO. Likewise, under normal circumstances, RFS is cleared when the receive FIFO has 11  
remaining entries of valid data. However, again due to variations, RFS may be cleared when 10 or  
9 entries of data remain.  
When the RFS bit is set, a DMA service request is made. An interrupt request is also made unless  
the receive FIFO interrupt request mask (RIE) bit is cleared. Even though more than eight entries  
of data may exist within the receive FIFO, the user must configure the DMA burst size to eight  
words. If programmed I/O is used to service the receive FIFO, a maximum of eight words may be  
removed without checking if data is valid. After this point, the receive FIFO not empty (RNE) flag  
must be polled before each read to see if more data remains. After the DMA or CPU empties the  
FIFO such that nine or more empty locations are available within the receive FIFO, the RFS flag  
(as well as the DMA and interrupt request) is automatically cleared.  
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11.10.10.6 Framing Error Status (FRE) (read/write, nonmaskable interrupt)  
The framing error status (FRE) bit is set when a frame alignment error is detected by the receive  
logic. A frame alignment error is detected on received data when a preamble is followed by  
something other than another preamble or a start flag.  
The following table shows the bit locations corresponding to the status and flag bits within HSSP  
status register 0. Note that the reset state of all writable status bits is unknown (indicated by  
question marks) and must be cleared (by writing a one to them) before enabling the HSSP. Also  
note that writes to reserved bits are ignored and reads return zeros.  
.
Address: 0h 8004 0074  
HSSR0  
Read/Write & Read-Only  
Bit  
7
6
5
FRE  
?
4
3
TFS  
0
2
RAB  
?
1
TUR  
?
0
EIF  
?
Reserved  
RFS  
0
Reset  
0
0
Bit  
Name  
EIF  
Description  
0
End/error in FIFO (read-only).  
0 – Bits 8–10 are not set within any of the eight bottom entries of the receive FIFO.  
Receive FIFO DMA service requests are enabled.  
1 – One or more tag bits (8 – 10) are set within one or more of the bottom eight entries of  
the receive FIFO. Request interrupt, disable receive FIFO DMA service requests.  
1
2
TUR  
RAB  
Transmit FIFO underrun.  
0 – Transmit FIFO has not experienced an underrun.  
1 – Transmit logic attempted to fetch data from transmit FIFO while it was empty;  
interrupt request signalled if not masked (if TUS=1).  
Receiver abort.  
0 – No abort has been detected for the incoming frame.  
1– Abort detected during receipt of incoming frame. Two or more chips containing no  
pulses (0000) detected on receive pin. EOF bit set in receive FIFO next to last piece of  
“good” data received before the abort, interrupt requested.  
3
TFS  
RFS  
Transmit FIFO service request (read-only).  
0 – Transmit FIFO is more than half-full (nine or more entries filled) or transmitter  
disabled.  
1 – Transmit FIFO is half-full or less (eight or fewer entries filled) and transmitter  
operation is enabled. DMA service request signalled; interrupt request signalled if not  
masked (if TIE=1).  
4
5
Receive FIFO service request (read-only).  
0 – Receive FIFO contains 11 or fewer entries of data or receiver disabled.  
1 – Receive FIFO is two- to three-fifths full (contains 9, 10, 11, or 12 entries of data) or  
more, and receiver operation is enabled. DMA service request signalled; interrupt  
request signalled if not masked (if RIE=1).  
FRE  
Framing error.  
0 – No framing errors encountered in the receipt of this data.  
1 – Framing error occurred; preamble followed by something other than another  
preamble or start flag, request interrupt.  
7..6  
Reserved.  
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Peripheral Control Module  
11.10.11 HSSP Status Register 1  
HSSP status register 1 (HSSR1) contains flags that indicate when the receiver is synchronized, the  
transmitter is active, the transmit FIFO is not full, the receive FIFO is not empty, and when an  
end-of-frame, CRC error, or underrun error has occurred. All bits within HSSR1 are read-only and  
noninterruptible.  
11.10.11.1 Receiver Synchronized Flag (RSY) (read-only, noninterruptible)  
The receiver synchronized (RSY) flag is a read-only bit that is set when the receiver is  
synchronized with the incoming data stream, and is cleared when the receive logic is in hunt mode  
(looking for the preamble to achieve byte and frame synchronization), or the receiver is disabled  
(RXE=0). This bit does not request an interrupt.  
11.10.11.2 Transmitter Busy Flag (TBY) (read-only, noninterruptible)  
The transmitter busy (TBY) flag is a read-only bit that is set when the transmitter is actively  
transmitting a frame (address, control, data, CRC, start or stop flag), and is cleared when the  
transmitter is idle (transmitting preambles) or the transmitter is disabled (TXE=0). This bit does not  
request an interrupt.  
11.10.11.3 Receive FIFO Not Empty Flag (RNE) (read-only, noninterruptible)  
The receive FIFO not empty flag (RNE) is a read-only bit that is set whenever the receive FIFO  
contains one or more bytes of valid data and is cleared when it no longer contains any valid data.  
This bit can be polled when using programmed I/O to remove remaining bytes of data from the  
receive FIFO because DMA service and CPU interrupt requests are made only when 12, 11, 10, or  
9 bytes reside within the FIFO. Data will remain after each service request as well as at the end of a  
frame. This bit does not request an interrupt.  
11.10.11.4 Transmit FIFO Not Full Flag (TNF) (read-only, noninterruptible)  
The transmit FIFO not full flag (TNF) is a read-only bit that is set whenever the transmit FIFO  
contains one or more entries that do not contain valid data and is cleared when the FIFO is  
completely full. This bit can be polled when using programmed I/O to fill the transmit FIFO over  
its halfway mark. This bit does not request an interrupt.  
11.10.11.5 End-of-Frame Flag (EOF) (read-only, noninterruptible)  
The end-of-frame flag (EOF) is set when the last byte of data within a frame (including aborted  
frames) resides within the bottom entry of the receive FIFO.  
The receive FIFO contains three tag bits (8, 9, and 10) that are not directly readable. The 8th bit is  
set at the top of the FIFO whenever the last byte within a frame is moved from the receive serial  
shifter to the top of the receive FIFO. This tag travels along with the last data value as it moves  
down the FIFO. Each time a data value is transferred to the bottom of the FIFO (caused by a read  
of the previous value), the state of the tag bit is moved from the FIFO to the EOF bit in the status  
register. Whenever EOF is set within the bottom eight entries of the receive FIFO, EIF is set within  
HSSR0, an interrupt is signalled, and the receive FIFO DMA request is disabled. After the  
end/error in FIFO (EIF) status bit is set, the user should always read HSSR1 first to check EOF  
before reading the data value from HSDR because EOF corresponds to the current data byte at the  
bottom of the receive FIFO and is updated each time data is removed from the FIFO.  
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11.10.11.6 CRC Error Status (CRE) (read-only, noninterruptible)  
The CRC error flag (CRE) is set when the CRC value calculated by the receive logic does not  
match the CRC value contained within the incoming serial data stream.  
The receive FIFO contains three tag bits (8, 9, and 10) that are not directly readable. Whenever a  
CRC error is detected, the 9th bit is set within the top entry of the receive FIFO corresponding to  
the last byte of data within the frame. This tag travels along with the last piece of data from the  
frame as it moves down the FIFO. Each time a data value is transferred to the bottom of the FIFO  
(caused by a read of the previous value), the state of the tag bit is moved from the FIFO to the CRE  
bit in the status register, indicating whether or not the frame has encountered a CRC error.  
Whenever CRE is set within the bottom half of the receive FIFO, EIF is set within HSSR0, an  
interrupt is signalled, and the receive FIFO DMA request is disabled. After the end/error in FIFO  
(EIF) status bit is set, the user should always read HSSR1 first to check CRE before reading the  
data value from HSDR because CRE corresponds to the current data byte at the bottom of the  
receive FIFO and is updated each time data is removed from the FIFO.  
11.10.11.7 Receiver Overrun Status (ROR) (read-only, noninterruptible)  
The receiver overrun flag (ROR) is set when the receive logic attempts to place data into the  
receive FIFO after it has been completely filled.  
The receive FIFO contains three tag bits (8, 9, and 10) that are not directly readable. The 10th bit is  
set within the top entry of the receive FIFO whenever an overrun occurs. This tag travels along  
with the last “good” data value before the overflow occurred as it moves down the FIFO. Each time  
a data value is transferred to the bottom of the FIFO (caused by a read of the previous value), the  
state of the tag bit is moved from the FIFO to the ROR bit in the status register, indicating that the  
next value in the FIFO is the last “good” piece of data before the overflow occurred. Whenever  
ROR is set within the bottom eight entries of the receive FIFO, EIF is set within HSSR0, an  
interrupt is signalled, and the receive FIFO DMA request is disabled. After the end/error in FIFO  
(EIF) status bit is set, the user should always read HSSR1 first to check ROR before reading the  
data value from HSDR because ROR corresponds to the current data byte at the bottom of the  
receive FIFO and is updated each time data is removed from the FIFO.  
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The following table shows the location of the flags within HSSP status register 1. The bits within  
this register are read-only and do not produce interrupt requests. Note that writes to bit 7 are  
ignored and reads return zero.  
Address: 0h 8004 0078  
HSSR1  
Read-Only  
Bit  
7
Res.  
0
6
ROR  
0
5
CRE  
0
4
3
TNF  
1
2
RNE  
0
1
TBY  
0
0
RSY  
0
EOF  
0
Reset  
Bit  
Name  
RSY  
Description  
0
Receiver synchronized flag (read-only).  
0 – Receiver is in hunt more or is disabled.  
1 – Receiver logic is synchronized with the incoming data (no interrupt generated).  
1
TBY  
Transmitter busy flag (read-only).  
0 – Transmitter is idle (continuous preambles) or disabled.  
1 – Transmit logic is currently transmitting a frame (address, control, data, CRC, or  
start/stop flag); no interrupt generated.  
2
3
4
5
RNE  
TNF  
EOF  
CRE  
Receive FIFO not empty (read-only).  
0 – Receive FIFO is empty.  
1 – Receive FIFO is not empty (no interrupt generated).  
Transmit FIFO not full (read-only).  
0 – Transmit FIFO is full.  
1 – Transmit FIFO is not full (no interrupt generated).  
End of frame (read-only).  
0 – Current frame has not completed.  
1 – The value at the bottom of the receive FIFO is the last byte of data within the frame.  
CRC error (read-only).  
0 – No CRC check errors encountered in the receipt of data.  
1 – CRC calculated on the incoming data. Does not match CRC value contained within  
the received frame.  
6
7
ROR  
Receive FIFO overrun (read-only).  
0 – Receive FIFO has not experienced an overrun.  
1 – Receive logic attempted to place data into receive FIFO while it was full; the next data  
value in the FIFO is the last piece of “good” data before the FIFO was overrun.  
Reserved.  
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11.10.12 UART Register Locations  
Table 11-16 shows the registers associated with the UART block and the physical addresses used to  
access them.  
Table 11-16. UART Control, Data, and Status Register Locations  
Address  
Name  
UTCR0  
Description  
UART control register 0  
0h 8003 0000  
0h 8003 0004  
0h 8003 0008  
0h 8003 000C  
0h 8003 0010  
0h 8003 0014  
0h 8003 0018  
0h 8003 001C  
0h 8003 0020  
UTCR1  
UTCR2  
UTCR3  
UTCR4  
UTDR  
UART control register 1  
UART control register 2  
UART control register 3  
UART control register 4  
UART data register  
Reserved  
UTSR0  
UTSR1  
UART status register 0  
UART status register 1  
0h 8003 0024 –  
0h 8003 005C  
Reserved  
11.10.13 HSSP Register Locations  
Table 11-17 shows the registers associated with the HSSP block and the physical addresses used to  
access them.  
Table 11-17. HSSP Control, Data, and Status Register Locations  
Address  
0h 8004 0060  
Name  
HSCR0  
Description  
HSSP control register 0  
0h 8004 0064  
HSCR1  
HSSP control register 1  
Reserved  
0h 8004 0068  
0h 8004 006C  
HSDR  
HSSP data register  
Reserved  
0h 8004 0070  
0h 8004 0074  
HSSR0  
HSSR1  
HSSP status register 0  
HSSP status register 1  
Reserved  
0h 8004 0078  
0h 8004 007C - 0h 8004 FFFF  
Note: HSCR2 resides within the same address space as the PPC.  
0h 9006 0028  
HSCR2  
HSSP Control register 2  
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11.11  
Serial Port 3 - UART  
Serial port 3 is a general-purpose, full-duplex, universal asynchronous receiver/transmitter (UART)  
that supports much of the functionality of the 16550 protocol. It can operate at baud rates from  
56.24 bps to 230.4 Kbps. It supports 7 or 8 bits of data (odd, even, or no parity), one start bit, either  
one or two stop bits, and can transmit a continuous break signal. An external clock can also be  
input using GPIO pin 20 to synchronously sample and drive data on either edge of the clock as  
programmed by the user. The external pins dedicated to this interface are TXD3 and RXD3. If use  
of the UART is not required, these pins can be used by the peripheral pin controller (PPC) to  
perform general- purpose input/output (noninterruptible).  
An 8-entry x 8-bit FIFO is used to buffer outgoing data, and a 12-entry x 11-bit FIFO is used to  
buffer incoming data (3 bits per entry are used to store framing, parity, and receive FIFO overrun  
error flags for each character received). The FIFOs are filled or emptied using the DMA or the  
CPU. An interrupt is generated when a framing, parity, or receiver overrun error is present within  
the bottom four entries of the receive FIFO, when the transmit FIFO is half-empty or the receive  
FIFO is one- to two-thirds full, when a begin and end of break is detected on the receiver, and when  
the receive FIFO is partially full and the receiver is idle for three or more frame periods.  
Modem control signals (RTS, CTS, DTR, and DSR) are not implemented in this block, but can be  
implemented using the general-purpose I/O port (GPIO) pins. See Chapter 9, “System Control  
11.11.1 UART Operation  
Following hardware reset, the UART is disabled, which causes the peripheral pin controller (PPC)  
to assume control of the UART’s pins. Reset causes the PPC to configure all of the peripheral pins  
as inputs, including the UART’s transmit (TXD3) and receive (RXD3) pins. Reset also causes the  
UART’s transmit and receive FIFOs to be flushed (all entries invalidated). Before enabling the  
UART, the user must first clear any writable or “sticky” status bits that are set by writing a one to  
each bit. Next, the desired mode of operation is programmed in the control registers. At this point,  
the user may “prime” the transmit FIFO by writing up to eight values, or the FIFO can remain  
empty and the transmit FIFO DMA or interrupt request may be used to trigger its service when the  
transmitter is enabled. When the UART is enabled, transmission and reception of data can begin on  
the transmit (TXD3) and receive (RXD3) pins.  
Figure 11-29 shows the format of a single UART data frame.  
Figure 11-29. Example UART Data Frame  
Start  
Bit  
Stop  
Bit 1  
Stop  
Bit 2  
Data  
<0>  
Data  
<1>  
Data  
<2>  
Data  
<3>  
Data  
<4>  
Data  
<5>  
Data  
<6>  
Data Parity  
<7> Bit  
Optional  
TXD3 or RXD3 pin  
Optional  
MSB  
LSB  
Receive data sample counter frequency = 16x bit frequency, each bit sampled on eighth clock.  
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11.11.1.1 Frame Format  
NRZ encoding is used by the UART to represent individual bit values. A one is represented by a  
line transition and a zero is represented by no line transition. Figure 11-30 shows the NRZ  
encoding of the data byte 8b 0100 1011. Note that the byte’s LSB is transmitted first.  
Figure 11-30. NRZ Bit Encoding Example – (0100 1011)  
LSB  
1
MSB  
0
Bit  
Value  
1
0
1
0
0
1
Digital  
Data  
NRZ  
Data  
Each data frame is between 9 bits and 12 bits long depending on the size of data programmed, if  
parity is enabled and if a second stop bit is enabled. The frame begins with a start bit that is  
represented by a high to low transition. Next, either 7 bits or 8 bits of data are transmitted,  
beginning with the least significant bit. An optional parity bit follows, which is set if even parity is  
enabled and an odd number of ones exist within the data byte, or if odd parity is enabled and the  
data byte contains an even number of ones. The data frame ends with either one or two stop bits as  
programmed by the user, which is represented by one or two successive bit periods of a logic one.  
Note that the receiver only tests for one stop bit per frame.  
11.11.1.2 Baud Rate Generation  
The baud or bit rate is derived by dividing down the 3.6864-MHz clock generated by the on-chip  
PLL. The clock is first divided by a programmable number between 1 and 4097, and then by a  
fixed value of 16. The receive baud clock is synchronized with the data stream using a digital PLL  
each time the start bit is detected on the receive data line. Receive data is then sampled halfway  
through each bit period by counting 8 of the 16 clocks, which are produced before the fixed divide  
by 16 takes place. (See Figure 11-29.)  
11.11.1.3 Receive Operation  
The UART receives incoming data by using a serial shifter. It latches the frame, strips it of its start,  
parity, and stop bits, and then places the data within receive FIFO. If parity is enabled, the number  
of data bits, which is one, is counted as data and is extracted from each frame. Parity is then  
checked by comparing this value to the stripped parity bit. Either odd or even parity is checked as  
specified by the programmer. If a parity error is detected, the parity error bit is set in the FIFO entry  
corresponding to the data value that caused the error. Additionally, if a logic zero is detected by the  
receive logic where a stop bit was expected, the framing error bit is set in the FIFO entry  
corresponding to the errant data. When the FIFO fills between one- to two-thirds full, an interrupt  
or DMA request is signalled. If the FIFO is completely filled and the receive logic attempts to place  
additional data within the FIFO, the overrun bit is set next to the last byte of data received within  
the FIFO. Any data received while the FIFO is completely full is discarded.  
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The parity, framing, and overrun error bits are transferred down the receive FIFO along with the data  
that caused the error. Whenever any of the four bottom FIFO entries contain one or more error bits that  
are set, an interrupt is generated and receive FIFO DMA requests are disabled until the error is flushed  
from the FIFO and the status bit that signalled the interrupt is cleared. At this point, the user should use  
programmed I/O to check the error bits and remove data one piece at a time until the four FIFO entries  
are flushed. Each time a data value is transferred to the bottom of the FIFO, the state of the parity,  
framing, and overrun bits within the last FIFO entry are automatically transferred to their respective  
flag bits in the status register. When any of these three flags are set in the UART status register, it  
indicates that the next data value available within the FIFO contains an error. The user must first check  
the state of these three flags to see if the next value within the FIFO contains an error, then read the  
FIFO value. After four values have been removed from the FIFO and the errors are identified, the  
DMA is automatically reenabled once the error in FIFO bits are removed from the FIFO.  
If the receive FIFO contains valid data and three frame periods elapse without the reception of data  
on RXD3, the receiver idle interrupt is generated. Also, if the receive logic detects a null character  
(all zeros, including the parity bit) followed by a framing error (stop bit is zero as well), the receive  
logic generates a beginning of break detect, which interrupts the CPU. Because breaks can be  
signalled for long periods of time, after the break is negated and the receive pin transitions high, the  
receive logic generates an end of break detect, which again interrupts the CPU.  
11.11.1.4 Transmit Operation  
The UART transmit logic operates at the same time as the receive logic (full-duplex). Data is taken  
from the transmit FIFO; start, parity, and stop bits are added to generate a frame; and the value is  
loaded into a serial shift register. The contents are shifted out onto the TXD3 pin, clocked by the  
programmed baud clock. When the transmit FIFO is emptied more than halfway, an interrupt or  
DMA request is signalled. If the transmit FIFO is completely emptied, the transmit line remains  
high (one) after the last data value is transmitted to indicate the transmitter is idle. The TXD3 pin  
remains high until additional data is written to the transmit FIFO.  
11.11.1.5 Transmit and Receive FIFOs  
To reduce chip size and power consumption, the UART’s FIFOs use self-timed logic (they are not  
clocked). Because of process and environmental variations, the depth at which a service request is  
triggered to empty the receive FIFO is variable. This variation spans a maximum of four FIFO  
entries; the receive FIFO service request can be made at four different FIFO depths.To compensate  
for this variability and guarantee that at least four valid entries of data exist within the FIFO before  
generating a service request, an extra four entries have been added to the receive FIFO (four entries  
more than the transmit FIFO). The transmit FIFO is 8 entries deep and the receive FIFO is 12  
entries deep. The point at which the receive FIFO service request is triggered spans the middle  
third of the 12-entry FIFO. The service request is signalled at a depth from one-third full to  
two-thirds full (when the FIFO contains five, six, seven, or eight entries of data).  
This service request variation applies only to an empty FIFO that is filled (receive FIFO). It does  
not apply to a full FIFO that is emptied (transmit FIFO). The transmit FIFO is guaranteed to signal  
a service request when it has four or more empty entries and negate the request when the FIFO  
contains five or more entries that are filled.  
If the DMA is used to service either one or both of the UART’s FIFOs, the burst size must be set to  
4 words even though more than four entries of data may exist within the receive FIFO. If  
programmed I/O is used to service the FIFOs, a maximum of 4 words may be added to the transmit  
FIFO without checking if more space is available. Likewise, a maximum of 4 words may be  
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removed from the receive FIFO without checking if more data is available. After this point, the  
user must poll a set of status bits that indicates if any data remains in the receive FIFO or if space is  
available in the transmit FIFO before emptying or filling the FIFOs any further.  
11.11.1.6 CPU and DMA Register Access Sizes  
Bit positioning, byte ordering, and addressing of the UART is described in terms of little endian  
ordering. All UART registers are 8 bits wide and are located in the least significant byte of  
individual words. The ARM peripheral bus does not support byte or half-word operations. All  
reads and writes of the UART by the CPU should be wordwide. Two separate dedicated DMA  
requests exist for both the transmit and the receive FIFO. If the DMA controller is used to service  
the transmit and/or receive FIFOs, the user must ensure the DMA is properly configured to perform  
bytewide accesses, using 4 bytes per burst.  
11.11.2 UART Register Definitions  
There are seven bytewide registers within the UART: four control registers, one data register, and  
two status registers. The control registers are used to program the baud rate, data length, number of  
stop bits, and odd or even parity. They are used to receive and transmit sample clock edge type, and  
to transmit a break. Also, they are used to enable or disable transmit and receive operation, parity,  
use of the sample clock input, and loopback mode. The data register is 8 bits and addresses the top  
location of the transmit FIFO and bottom location of the receive FIFO. When it is read, the receive  
FIFO is accessed, and when it is written, the transmit FIFO is accessed. The status registers contain  
bits that signal the transmit FIFO service request, receive FIFO service request, receiver idle, the  
begin and end of break detect, and error in FIFO conditions. Each of these status conditions signal  
an interrupt request to the interrupt controller. The status registers also flag when the UART is  
actively transmitting characters, when the transmit FIFO is not full, when the receive FIFO is not  
empty, and when a parity, framing, or overrun error was detected for the data value currently  
located in the bottom entry of the receive FIFO (no interrupt generated).  
11.11.3 UART Control Register 0  
UART control register 0 (UTCR0) contains seven different bit fields that control various functions  
within the UART.  
11.11.3.1 Parity Enable (PE)  
The parity enable (PE) bit is used to enable or disable parity checking by the receive data logic as  
well as parity generation by the transmit logic. When parity is enabled (PE=1), the odd/even parity  
select (OES) control bit is decoded to determine which type of parity should be checked and  
generated. The parity of each data frame received is checked. If the parity type programmed in the  
OES bit does not match the parity of the data received, the parity error (PRE) bit is set in the same  
entry in the receive FIFO where the errant data resides. When parity is disabled (PE=0), the parity  
check and generation logic is disabled, parity bits are not inserted into transmitted frames, and the  
receive logic expects a stop bit to occur after the MSB of each data value is received.  
11.11.3.2 Odd/Even Parity Select (OES)  
The odd/even parity select (OES) bit is used to select whether odd or even parity should be used by  
the transmit and receive logic. When OES=0, odd parity is selected; when OES=1, even parity is  
selected. When parity is enabled (PE=1), the parity bit is placed after the data’s MSB in each frame.  
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The transmit logic sets or clears the parity bit to make the total number of ones transmitted  
(including the parity bit) match the parity type programmed using OES  
(if even parity is selected (OES=1) and there is an odd number of ones in the data to be  
transmitted, the parity bit is set). The receive data logic counts the number of ones encountered in  
the incoming data stream (including the parity bit), then strips the parity bit from the data. If the  
parity type of the frame does not match the parity selected by OES, the parity error bit is set (bit 8)  
within the FIFO entry corresponding to the data that produced the parity error.  
11.11.3.3 Stop Bit Select (SBS)  
The stop bit select (SBS) bit selects whether one or two stop bits should be used in transmission.  
When SBS=0, one stop bit is inserted in the transmit frame for each character. When SBS=1, two  
stop bits are inserted. SBS does not affect the UART’s receive logic. The receiver always checks to  
make sure there is at least one stop bit per character.  
11.11.3.4 Data Size Select (DSS)  
The data size select (DSS) bit is programmed to select the size of the data transmitted and received  
within each frame. Data can be 7 or 8 bits in length. When 7-bit data is programmed, the data is  
right justified within the FIFOs. The unused bit is zero filled within the receive FIFO, and is  
ignored within the transmit FIFO. Note that the user must right justify data supplied to the transmit  
FIFO when 7-bit data is selected.  
11.11.3.5 Sample Clock Enable (SCE)  
The sample clock enable (SCE) bit is used to enable or disable the use of a clock input from a  
GPIO pin to synchronously sample and drive data to and from the UART. When SCE=0, the  
on-chip 3.6864-MHz PLL, the UART’s programmable baud rate generator, and the receive logic’s  
digital PLL are used. When SCE=1, a clock is input from a GPIO pin and is used to synchronously  
drive both the transmit and receive logic. Note that the user must configure the GPIO pin as an  
input by clearing the corresponding bit in the GPIO pin direction register (GPDR) and switch  
control of the GPIO pin to the UART by setting the corresponding bit in the GPIO alternate  
function register (GAFR). See Chapter 9, “System Control Module”.  
For the receive logic, the RCE bit is decoded to select which edge of the input clock is used to latch  
each bit of the incoming frame. Note that the clock is not embedded within the data stream and the  
digital PLL is shut down to conserve power. For the transmit logic, the TCE bit is decoded to select  
which edge of the input clock is used to drive each bit of the outgoing frame. Note that the clock  
driving the programmable baud rate generator is shut down when SCE=1 to conserve power. Also  
note that SCE does not affect the frame format of data being transmitted and received by the  
UART.  
The SA-1100 has a total of three UARTs (serial ports 1, 2 and 3). When the external sample clock  
function is enabled, serial port 1 uses the GPIO<18> pin and serial port 3 uses GPIO<19>. Serial  
port 2 does not support the sample clock function.  
11.11.3.6 Receive Clock Edge Select (RCE)  
When SCE=1, the receive clock edge select (RCE) bit is used to select which edge of the clock  
input from the GPIO pin to use (rising or falling) to synchronously sample data from the receive  
pin. When RCE=0, each bit received is sampled on the rising edge of the sample input clock; when  
RCE=1, bits are sampled on the clock’s falling edge. Note that the internal baud rate generator and  
receive logic’s digital PLL are not used in this mode. RCE is ignored when SCE=0.  
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11.11.3.7 Transmit Clock Edge Select (TCE)  
When SCE=1, the transmit clock edge select (TCE) bit is used to select which edge of the clock  
input from the GPIO pin to use (rising or falling) to synchronously drive data onto the transmit pin.  
When TCE=0, each bit transmitted is driven on the rising edge of the sample input clock; when  
TCE=1, bits are driven on the clock’s falling edge. Note that the internal baud rate generator is not  
used in this mode. TCE is ignored when SCE=0.  
The following table shows the bit locations corresponding to the seven different control bit fields  
within UART control register 0. The UART must be disabled (RXE=TXE=0) when changing the  
state of any bit within this register. The reset state of these control bits is unknown (indicated by  
question marks) and must be initialized before enabling the UART. Note that writes to bit 7 are  
ignored and reads return zero.  
Address: 0h 8005 0000  
UTCR0  
Read/Write  
Bit  
7
Res  
0
6
TCE  
?
5
RCE  
?
4
3
DSS  
?
2
SBS  
?
1
OES  
?
0
PE  
?
SCE  
?
Reset  
Bit  
Name  
PE  
Description  
0
Parity enable.  
0 – Parity checking on received data and parity generation on transmitted data is disabled.  
1 – Parity checking on received data and parity generation on transmitted data is enabled.  
1
OES  
Odd/even parity select.  
0 – Odd parity checking/generation selected. Parity error bit set if even number of ones  
counted in data field (including the parity bit).  
1 – Even parity checking/generation selected. Parity error bit set if odd number of ones  
counted in data field (including the parity bit).  
2
3
SBS  
DSS  
Stop bit select.  
0 – One stop bit transmitted per frame.  
1 – Two stop bits transmitted per frame.  
Note: Receiver not affected by SBS; always checks for one stop bit.  
Data size select.  
0 – 7-bit data.  
1 – 8-bit data.  
Note: For 7-bit mode, the data is right justified within the FIFO entries, the MSBs in the  
receive FIFO are zero filled, and the MSBs in the transmit FIFO are ignored.  
4
SCE  
Sample clock enable.  
0 – on-chip baud rate generator and digital PLL used to transmit and receive  
asynchronous data.  
1 – A clock is input via GPIO pin 20 and is used synchronously to sample receive data  
and drive transmit data.  
Note: Serial port 1’s UART uses GPIO pin 18 for the sample clock input; serial port 2  
does not support the sample clock function. The user must also program the appropriate  
bits in the GPDR and GAFR registers within the system control module.  
5
6
RCE  
TCE  
Receive clock edge select.  
0 – Rising edge of clock input on GPIO pin 20 used to latch data from the receive pin if SCE=1.  
1 – Falling edge of clock input on GPIO pin 20 used to latch data from the receive pin if SCE=1.  
Transmit clock edge select.  
0 – Rising edge of clock input on GPIO pin 20 used to drive data onto the transmit pin if SCE=1.  
1 – Falling edge of clock input on GPIO pin 20 used to drive data onto the transmit pin if  
SCE=1.  
7
Reserved.  
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11.11.4 UART Control Registers 1 and 2  
UART control register 1 (UTCR1) contains the upper 4 bits and UTCR2 the lower 8 bits of the  
baud rate divisor field.  
11.11.4.1 Baud Rate Divisor (BRD)  
The 12-bit baud rate divisor (BRD) field is used to select the baud or bit rate of the UART. A total  
of 4096 different baud rates can be selected, ranging from a minimum of 56.24 bps to a maximum  
of 230.4 Kb/ps. The baud rate generator uses the 3.6864-MHz clock generated by the on-chip PLL  
divided by 16 to generate the bit clock. A digital PLL is used to synchronize the baud rate of the  
receiver each time the start bit is detected on the receive pin and each bit of the receive data stream  
is sampled on the eighth clock of the divide by 16 counter (halfway through the bit period). The  
resultant baud rate, given a specific BRD value or required BRD value and given a desired baud  
rate, can be calculated using the following two respective equations, where BRD is the decimal  
equivalent of the binary value programmed within the bit field:  
6
3.6864×10  
BaudRate = --------------------------------------  
16x(BRD + 1)  
6
3.6864×10  
BRD = --------------------------------------- 1  
16xBaudRate  
The following tables show the bit locations corresponding to the baud rate divisor field that is split  
between two 8-bit registers. The upper four bits of BRD reside within UTCR1 and the lower eight bits  
reside within UTCR2. The UART must be disabled (RXE=TXE=0) whenever these registers are written.  
The reset state of the BRD field is unknown (indicated by question marks) and must be initialized before  
enabling the UART. Note that writes to reserved bits are ignored and reads return zeros.  
Address: 0h 8005 0004  
UTCR1  
Read/Write  
Bit  
7
6
5
0
4
0
3
?
2
1
0
?
Reserved  
BRD<11:8>  
Reset  
0
0
?
?
Bit  
3..0  
Name  
BRD<11:8> Baud rate divisor.  
Description  
Encoded value (from 0 to 4096) used to generate the baud rate of the UART.  
6
Baud Rate = 3.6864x10 /(16x(BRD+1)), where BRD is a decimal value.  
7..4  
Reserved.  
Address: 0h 8005 0008  
UTCR2  
Read/Write  
Bit  
Reset  
7
6
5
?
4
3
2
?
1
0
?
BRD<7:0>  
?
?
?
?
?
Bit  
7..0  
Name  
BRD<7:0> Baud rate divisor.  
Description  
Encoded value (from 0 to 4096) used to generate the baud rate of the UART.  
6
Baud Rate = 3.6864x10 /(16x(BRD+1)), where BRD is a decimal value.  
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11.11.5 UART Control Register 3  
UART control register 3 (UTCR3) contains six different bit fields that control various functions  
within the UART.  
11.11.5.1 Receiver Enable (RXE)  
The receiver enable (RXE) bit is used to enable and disable all UART receive operations. When RXE=1,  
the UART receive logic is enabled; when RXE=0, it is disabled. When the receiver is disabled, control of  
the RXD3 pin is given to the peripheral pin controller (PPC) so that it may be used for general-purpose  
page 11-184 for a description of the PPC.  
It is required that the user first program all other control bits before setting RXE (even the transmit  
bits). If the RXE bit is cleared to zero while the UART is actively receiving data, reception is  
stopped immediately and the remaining bits within the receive serial shifter are reset. In addition,  
all entries within the receive FIFO are reset (all other control/status/flag bits remain intact).  
11.11.5.2 Transmitter Enable (TXE)  
The transmitter enable (TXE) bit is used to enable and disable all UART transmit operations. When  
TXE=1, UART transmit logic is enabled; when TXE=0, it is disabled. When the transmitter is disabled,  
control of the TXD3 pin is given to the peripheral pin controller (PPC) for general-purpose input and  
page 11-184 for a description of the PPC.  
It is required that the user first program all other control bits before setting TXE (even the receive  
bits). If the TXE bit is cleared to zero while the UART is actively transmitting data, transmission is  
stopped immediately and the remaining bits within the transmit serial shifter are reset. In addition,  
all entries within the transmit FIFO are reset (all other control/status/flag bits remain intact).  
11.11.5.3 Break (BRK)  
The break (BRK) control bit is used to continuously transmit a break by forcing the transmit pin  
(TXD3) low. When the BRK bit is set, the transmit pin is forced low immediately. If the transmitter is  
actively transmitting data, the remaining bits in the serial shifter continue to be shifted out, but the bits  
are ignored (not placed on the transmit pin). Asserting BRK also prevents the transmit logic from  
fetching any additional data from the transmit FIFO once the shifter is empty. The transmit pin  
remains low until the BRK bit is cleared, or alternatively, if the transmitter is disabled (TXE=0, or a  
reset occurs). Once BRK is negated, transmission starts again. The user must ensure that the BRK bit  
is asserted long enough to cause the off-chip receiver to detect the break condition. The user should  
also check the transmitter busy (TBY) flag in the status register to ensure that no bits remain in the  
transmitter’s serial shifter before negating BRK. TBY is asserted as long as the transmitter is actively  
clocking data through the serial shifter. Once the TBY bit becomes zero, the BRK bit can be negated,  
and data is once again fetched from the transmit FIFO. Break does not affect the receive portion of the  
FIFO; normal operation on the receive line continues during the signalling of a break.  
11.11.5.4 Receive FIFO Interrupt Enable (RIE)  
The receive FIFO interrupt enable (RIE) bit is used to mask or enable both the receive FIFO service request  
interrupt and receiver idle interrupt. When RIE=0, the interrupts are masked and the receive FIFO service  
request (RFS) and receiver idle status (RID) bits are ignored by the interrupt controller. When RIE=1, the  
interrupts are enabled and whenever RFS or RID is set (one), an interrupt request is made to the interrupt  
controller. Note that programming RIE=0 does not affect the current state of RFS or RID nor the receive  
logic’s ability to set and clear these bits; it only blocks the generation of the interrupt request. Also note that  
RIE does not affect generation of the receive FIFO DMA request that is asserted whenever RFS=1.  
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11.11.5.5 Transmit FIFO Interrupt Enable (TIE)  
The transmit FIFO interrupt enable (TIE) bit is used to mask or enable the transmit FIFO service  
request interrupt. When TIE=0, the interrupt is masked and the state of the transmit FIFO service  
request (TFS) bit is ignored by the interrupt controller. When TIE=1, the interrupt is enabled, and  
whenever TFS is set (one), an interrupt request is made to the interrupt controller. Note that  
programming TIE=0 does not affect the current state of TFS nor the transmit FIFO logic’s ability to  
set and clear TFS; it only blocks the generation of the interrupt request. Also note that TIE does  
not affect generation of the transmit FIFO DMA request that is asserted whenever TFS=1.  
11.11.5.6 Loopback Mode (LBM)  
The loopback mode (LBM) bit is used to enable and disable the ability of the UART transmit and  
receive logic to communicate. When LBM=0, the UART operates normally. The transmit and receive  
data paths are independent and communicate via their respective pins. When LBM=1, the output of  
the transmit serial shifter is directly connected to the input of the receive serial shifter internally, and  
control of the TXD3 and RXD3 pins is given to the peripheral pin control (PPC) unit.  
The following table shows the bit location of the bits within UART control register 3. RXE and  
TXE are the only control bits that are reset to a known state to ensure the UART is disabled  
following a reset of the SA-1100. The reset state of all other control bits is unknown (indicated by  
question marks) and must be initialized before enabling the UART. Note that UTCR3 is the only  
control register that may be written while the UART is enabled. Also note that writes to reserved  
bits are ignored and reads return zeros.  
Address: 0h 8005 000C  
UTCR3  
Read/Write  
Bit  
7
6
5
LBM  
?
4
3
RIE  
?
2
BRK  
?
1
TXE  
0
0
RXE  
0
Reserved  
TIE  
?
Reset  
0
0
Bit  
Name  
RXE  
Description  
0
1
2
3
Receiver enable.  
0 – UART receive operation disabled; PPC is given control of RXD3.  
1 – UART receive operation enabled.  
TXE  
BRK  
RIE  
Transmitter enable.  
0 – UART transmit operation disabled; PPC is given control of TXD3.  
1 – UART transmit operation enabled.  
Break.  
0 – UART in normal operation.  
1 – Force TXD3 low (all bits in the frame are a zero) to generate a break.  
Receive FIFO interrupt enable.  
0 – Receive FIFO one- to two-thirds full (or more) and receiver idle conditions do not  
generate an interrupt (RFS and RID bit ignored).  
1 – Receive FIFO one- to two-thirds full (or more) and receiver idle conditions generate  
an interrupt (state of RFS and RID sent to interrupt controller).  
4
5
TIE  
Transmit FIFO interrupt enable.  
0 –Transmit FIFO half-full or less condition does not generate an interrupt (TFS bit  
ignored).  
1 – Transmit FIFO half-full or less condition generates an interrupt (state of TFS sent to  
interrupt controller).  
LBM  
Loopback mode.  
0 – Normal serial port operation enabled.  
1 – Output of transmit serial shifter is connected to input of receive serial shifter internally  
and control of TXD3 and RXD3 pins is given to the PPC unit.  
7.. 6  
Reserved.  
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11.11.6 UART Data Register  
The UART data register (UTDR) is an 8-bit register corresponding to both the top and bottom  
entries of the transmit and receive FIFOs, respectively.  
When UTDR is read, the lower 8 bits of the bottom entry of the 10-bit receive FIFO are accessed. As  
data enters the top of the receive FIFO, bits 8..10 are used to indicate various error conditions that  
occur during reception of each piece of data. The error bits are transferred down the FIFO along with  
the value that caused the error. When data reaches the bottom, bit 8 of the bottom FIFO entry is  
automatically transferred to the parity error (PRE) flag, bit 9 to the framing error (FRE) flag, and bit  
10 to the receiver overrun (ROR) flag, all within the UART status register. The user can read these  
flags to determine if the value at the bottom of the FIFO encountered an error during reception. After  
checking the flags, the FIFO value can then be read, which causes the data in the next location of the  
receive FIFO to automatically be transferred down to the bottom entry and its error bits to be  
transferred to the status register. The error in FIFO (EIF) flag bit is set whenever one or more of the  
error bits (8..10) is set within any of the bottom four entries of the receive FIFO and is cleared when  
no error bits are set in the bottom four entries of the FIFO. When EIF is set, an interrupt is generated  
and receive FIFO DMA requests are disabled so that the user can manually empty the FIFO, always  
checking the parity, framing, and overrun flags in the status register first before removing the data  
values from the FIFO. After each entry is removed, the user should check the EIF bit to see if any  
errors remain, and repeat the procedure until all errors are flushed from the FIFO. Once EIF is  
cleared, servicing of the receive FIFO by the DMA controller is automatically reenabled.  
When UTDR is written, the topmost entry of the 8-bit transmit FIFO is accessed. After a write, data is  
automatically transferred down to the lowest location within the transmit FIFO that does not already  
contain valid data. Data is removed from the bottom of the FIFO one piece at a time by the transmit  
logic and is loaded into the transmit serial shifter along with start and stop bits (and the optional parity  
and second stop bits), then is serially shifted out onto the TXD3 pin at the programmed baud rate.  
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The following table shows the bit locations corresponding to the data field, parity, framing, and  
receiver overrun error bits within the UART data register. Note that both FIFOs are cleared when  
the SA-1100 is reset, the transmit FIFO is cleared when writing TXE=0, and the receive FIFO is  
cleared when writing RXE=0.  
Address: 0h 8005 0014  
UTDR  
Read/Write  
Bit  
10  
ROR  
0
9
FRE  
0
8
PRE  
0
7
0
6
0
5
4
3
2
1
0
0
Bottom of receive FIFO data  
Reset  
0
0
0
0
0
Read Access  
(Note: ROR, FRE, PRE are not read, but rather are transferred to  
corresponding status bits in UTSR1 each time a data value is transferred to UTDR.)  
Bit  
7
0
6
0
5
4
3
2
1
0
0
0
Top of transmit FIFO data  
Reset  
0
0
0
0
Write Access  
Bit  
7..0  
Name  
DATA  
Description  
Top/bottom of transmit/receive FIFO data.  
Read – Bottom of receive FIFO data.  
Write – Top of transmit FIFO data.  
8
PRE  
FRE  
ROR  
Parity error.  
0 – No parity errors encountered in the receipt of this data (or parity disabled).  
1 – Parity error encountered in the receipt of this data.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 8 from the  
last FIFO entry is transferred to the PRE bit in UTSR1.  
9
Framing error.  
0 – Stop bit for this frame was a one.  
1 – Stop bit for this frame was a zero.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 9 from the  
last FIFO entry is transferred to the FRE bit in UTSR1.  
10  
Receiver overrun.  
0 – No receiver overrun has been detected.  
1 – Receive logic attempted to place data into receive FIFO while it was full; one or more  
data values following this entry were lost.  
Note: Each time an 11-bit value reaches the bottom of the receive FIFO, bit 10 from the  
last FIFO entry is transferred to the ROR bit in UTSR1.  
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11.11.7 UART Status Register 0  
UART status register 0 (UTSR0) contains bits that signal the transmit FIFO interrupt request,  
receive FIFO interrupt request, receiver idle detect, the begin and end of receiver break detect  
conditions, and the error in receive FIFO condition. Each of these hardware-detected events signals  
an interrupt request to the interrupt controller.  
Interruptible status bits signal an interrupt requested as long as the bit is set. Once the bit is cleared,  
the interrupt is cleared. Read/write bits are called status bits, read-only bits are called flags. Status  
bits are referred to as “sticky” (once set by hardware, must be cleared by software). Writing a one  
to a sticky status bit clears it; writing a zero has no effect. Read-only flags are set and cleared by  
hardware; writes have no effect. Additionally, some bits that cause interrupts have corresponding  
enable/mask bits in the control registers and are indicated in the following section headings. Note  
that the user has the ability to mask all UART interrupts by clearing bit 17 within the interrupt  
controller mask register (ICMR). See the Section 9.2, “Interrupt Controller” on page 9-11.  
11.11.7.1 Transmit FIFO Service Request Flag (TFS) (read-only, maskable  
interrupt)  
The transmit FIFO service request flag (TFS) is a read-only bit that is set when the transmit FIFO is  
nearly empty and requires service to prevent an underrun. TFS is set any time the transmit FIFO  
has four or fewer entries of valid data (half-full or less), and is cleared when it has five or more  
(more than half-full) entries of valid data. When the TFS bit is set, a DMA service request is made.  
An interrupt request is also made unless the transmit FIFO interrupt request mask (TIE) bit is  
cleared. After the DMA or CPU fills the FIFO such that five or more locations are filled within the  
transmit FIFO, the TFS flag (as well as the DMA and interrupt request) is automatically cleared.  
11.11.7.2 Receive FIFO Service Request Flag (RFS) (read-only, maskable  
interrupt)  
The receive FIFO service request flag (RFS) is a read-only bit that is set when the receive FIFO is  
nearly filled and requires service to prevent an overrun. The amount of data that causes RFS to be  
set is nondeterministic. However, the range in which RFS will be set is guaranteed. RFS is set at  
some point when the receive FIFO is one- to two-thirds full (or more). The UART’s FIFOs are  
self-timed to reduce cost and save power. As a result, the depth at which the receive FIFO service  
request is generated is variable. This is the reason the receive FIFO is 12 entries deep instead of  
eight like the transmit FIFO. At which entry in the FIFO the request is actually triggered is  
dependent on IC process, operating temperature, and so on. The receive FIFO is designed to signal  
the RFS bit to be set when it contains eight entries of valid data. However, because of the  
variability of the self-timed logic, RFS may also be set when seven, six, or five entries of valid data  
are present within the FIFO. Likewise, under normal circumstances, RFS is cleared when the  
receive FIFO has seven remaining entries of valid data. However, again due to variations, RFS may  
be cleared when six, five, or four entries of data remain.  
When the RFS bit is set, a DMA service request is made. An interrupt request is also made unless  
the receive FIFO interrupt request enable (RIE) bit is cleared. Even though more than four entries  
of data may exist within the receive FIFO, the user must configure the DMA burst size to 4 words.  
If programmed I/O is used to service the receive FIFO, a maximum of 4 words may be removed  
without checking if data is valid. After this point, the receive FIFO not empty (RNE) flag must be  
polled before each read to see if more data remains. After the DMA or CPU empties the FIFO such  
that five or more empty locations are available within the receive FIFO, the RFS flag (as well as the  
DMA and interrupt request) is automatically cleared.  
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11.11.7.3 Receiver Idle Status (RID) (read/write, maskable interrupt)  
The receiver idle status bit (RID) is set when the receiver is enabled (RXE=1), the receive FIFO is  
not empty (contains at least one entry of data), and three frame periods elapse without any data  
having being received. When RID is set, an interrupt request is made unless the receive FIFO  
interrupt request mask (RIE) bit is cleared.  
11.11.7.4 Receiver Begin of Break Status (RBB) (read/write, nonmaskable  
interrupt)  
The receiver begin of break status bit (RBB) is set when the receive logic detects a null character  
(contains all zeros, including the parity bit), followed by a framing error, which indicates the start  
bit is zero. In other words, a begin of break is detected when the receive line is held low for one  
frame duration (whatever size the frame is programmed to). When RBB is set, an interrupt is  
signalled, a single null frame is placed in the receive FIFO, the framing error bit is set, and all  
subsequent null frames with framing errors are ignored (not placed within the FIFO). After RBB is  
cleared by the user, it cannot be set again until the receiver end of break status (REB) bit is set. This  
interlock is used to prevent added null characters from entering the receive FIFO, and also allows  
the user to clear the RBB bit (clearing the interrupt) and wait for the receiver end of break interrupt  
(described in the next section). This interlock is cleared when REB is set, when RXE is cleared, or  
when the SA-1100 is reset.  
11.11.7.5 Receiver End of Break Status (REB) (read/write, nonmaskable  
interrupt)  
The receiver end of break status bit (REB) is set when the receive pin transitions high (rising edge)  
and the RBB interlock is currently set (described in the preceding section). In other words, an end  
of break is detected after a begin of break is detected and the receive line transitions from low to  
high (indicating a new frame is about to occur or the receiver is entering the idle state). When REB  
is set, an interrupt is signalled, and the RBB interlock is cleared, allowing any future data frame to  
be stored to the receive FIFO. After the bit is cleared, it cannot be set again until the receiver begin  
of break status (RBB) bit is once again set.  
11.11.7.6 Error in FIFO Flag (EIF) (read-only, nonmaskable interrupt)  
The error in FIFO flag (EIF) is a read-only bit that is set when any error bits (8 through 10) are set  
within the bottom four entries of the receive FIFO and is cleared when no error bits are set within  
the bottom four entries of the FIFO. When EIF is set, an interrupt is signalled and DMA requests to  
empty the receive FIFO are disabled until EIF is cleared. To discover the source of the errors, the  
user should check the state of the FRE, PRE, and ROR bits in UTSR1, then read the corresponding  
value from UTDR. This procedure should be repeated until EIF is cleared because errors that are  
present within any of the four lowest entries in the receive FIFO will set EIF. Once all error tags are  
cleared from the bottom half of the receive FIFO, EIF is automatically cleared, which in turn,  
clears the interrupt and reenables the receive FIFO DMA request.  
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The following table shows the bit locations corresponding to the status bits within UART status  
register 0. Note that the reset state of all writable status bits is unknown (indicated by question  
marks) and must be cleared (by writing a one to them) before enabling the UART. Also note that  
writes to reserved bits are ignored and reads return zeros.  
.
Address: 0h 8005 001C  
UTSR0  
Read/Write & Read-Only  
Bit  
7
6
5
EIF  
0
4
REB  
?
3
2
RID  
?
1
RFS  
0
0
TFS  
0
Reserved  
RBB  
?
Reset  
0
0
Bit  
Name  
TFS  
Description  
0
Transmit FIFO service request (read-only).  
0 – Transmit FIFO is more than half-full (five or more entries filled) or transmitter  
disabled.  
1 – Transmit FIFO is half-full (four or fewer entries filled) and transmitter operation is  
enabled, DMA service request signalled, and interrupt request signalled if not masked (if  
TIE=1).  
1
RFS  
Receive FIFO service request (read-only).  
0 – Receive FIFO contains seven or fewer entries of data or receiver disabled.  
1 – Receive FIFO is one- to two-thirds full (contains 5, 6, 7, or 8 entries of data) or more,  
and receiver operation is enabled, DMA service request signalled, and interrupt request  
signalled if not masked (if RIE=1).  
2
3
RID  
Receiver idle.  
0 – Receiver is busy, receive FIFO is empty, or receiver is disabled.  
1 – Receiver is enabled, receive FIFO not empty, 3 frame times elapsed without  
receiving data, request interrupt.  
RBB  
Receiver begin of break.  
0 – No break detected.  
1 – Null character followed by parity and stop bits containing zeroes received, request  
interrupt.  
Note: Setting this bit allows the setting of REB, and also prevents further null characters  
with framing errors from being stored in the receive FIFO (only one stored).  
4
5
REB  
Receiver end of break.  
0 – No end of break detected.  
1 – Beginning of break was detected (interlock set) and a rising edge detected on the  
receive pin, request interrupt.  
Note: Setting of this bit allows the setting of RBB, and also allows characters to once  
again be stored in the receive FIFO.  
EIF  
Error in FIFO (read-only).  
0 – Bits 8..10 are not set within any of the four bottom entries of the receive FIFO,  
receive FIFO DMA service requests are enabled.  
1 – One or more error bits (8..10) are set within one or more of the bottom four entries of  
the receive FIFO, request interrupt, disable receive FIFO DMA service requests.  
7.. 6  
Reserved.  
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11.11.8 UART Status Register 1  
UART status register 1 (UTSR1) contains flags that indicate when the UART is actively  
transmitting characters, that the transmit FIFO is not full, that the receive FIFO is not empty, and  
when parity, framing, overrun, and underrun errors have occurred. All bits within UTSR1 are  
read-only and are noninterruptible.  
11.11.8.1 Transmitter Busy Flag (TBY) (read-only, noninterruptible)  
The transmitter busy (TBY) flag is a read-only bit that is set when the transmitter is actively  
processing data for transmission (the serial shifter contains data), and is cleared when the  
transmitter is idle or is disabled (TXE=0). This bit does not request an interrupt.  
11.11.8.2 Receive FIFO Not Empty Flag (RNE) (read-only, noninterruptible)  
The receive FIFO not empty flag (RNE) is a read-only bit that is set when the receive FIFO  
contains one or more bytes of valid data and is cleared when it no longer contains any valid data.  
This bit can be polled when using programmed I/O to remove remaining bytes of data from the  
receive FIFO because DMA service and CPU interrupt requests are made only when 8, 7, 6, or 5  
bytes reside within the FIFO. This bit does not request an interrupt.  
11.11.8.3 Transmit FIFO Not Full Flag (TNF) (read-only, noninterruptible)  
The transmit FIFO not full flag (TNF) is a read-only bit that is set when the transmit FIFO contains  
one or more entries that do not contain valid data and is cleared when the FIFO is completely full.  
This bit can be polled when using programmed I/O to fill the transmit FIFO over its halfway mark.  
This bit does not request an interrupt.  
11.11.8.4 Parity Error Flag (PRE) (read-only, noninterruptible)  
The parity error flag (PRE) is set when parity is enabled (PE = 1), and the parity type programmed  
using OES does not correspond to the parity check of the incoming serial data stream, which is  
calculated by the receive logic. The parity error bit is set when PE=1, OES=0, and UTDR<7:0>,  
and the incoming parity bit contain an even number of ones, or PE=1, OES=1, and UTDR<7:0>,  
and the incoming parity bit contain an odd number of ones.  
The receive FIFO contains three bits (8, 9, and 10) that are not directly readable. The 8th bit in the  
FIFO is set at the top of the FIFO whenever a byte of data that incurs a parity error is moved from  
the receive serial shifter to the top of the receive FIFO. This tag travels along with the errant data  
value as it moves down the FIFO. Each time a data value is transferred to the bottom of the FIFO  
(caused by a read of the previous value), the state of this bit is moved from the FIFO to the PRE bit  
in the status register. After the error in FIFO (EIF) status bit is set, the user should always read  
UTSR1 first to check PRE before reading the data value from UDR because PRE corresponds to  
the current data byte at the bottom of the receive FIFO and is updated each time data is removed  
from the FIFO.  
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11.11.8.5 Framing Error Flag (FRE) (read-only, noninterruptible)  
The framing error status bit (FRE) is set when the stop bit within a frame of incoming serial data is  
a zero instead of a one.  
The receive FIFO contains three bits (8, 9, and 10) that are not directly readable. The 9th bit in the  
FIFO is set at the top of the FIFO whenever a byte of data that incurs a framing error is moved from  
the receive serial shifter to the top of the receive FIFO. This tag travels along with the errant data  
value as it moves down the FIFO. Each time a data value is transferred to the bottom of the FIFO  
(caused by a read of the previous value), the state of this bit is moved from the FIFO to the FRE bit in  
the status register. After the error in FIFO (EIF) status bit is set, the user should always read UTSR1  
first to check FRE before reading the data value from UDR because FRE corresponds to the current  
data byte at the bottom of the receive FIFO and is updated each time data is removed from the FIFO.  
11.11.8.6 Receiver Overrun Flag (ROR) (read-only, noninterruptible)  
The receiver overrun status bit (ROR) is set when the receive logic attempts to place data into the  
receive FIFO after it has been completely filled.  
The receive FIFO contains three bits (8, 9, and 10) that are not directly readable. The 10th bit in the  
FIFO is set within the top entry of the receive FIFO whenever an overrun occurs. This tag travels  
along with the last “good” data value before the overflow occurred as it moves down the FIFO.  
Each time a data value is transferred to the bottom of the FIFO (caused by a read of the previous  
value), the state of this bit is moved from the FIFO to the ROR bit in the status register, indicating  
that the next value in the FIFO is the last “good” piece of data before the overflow occurred. After  
the error in FIFO (EIF) status bit is set, the user should always read UTSR1 first to check ROR  
before reading the data value from UDR because ROR corresponds to the current data byte at the  
bottom of the receive FIFO and is updated each time data is removed from the FIFO.  
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The following table shows the bit locations corresponding to the flag bits within UART status  
register 1. Note that these flags do not generate interrupts, all bits are read-only, writes are ignored,  
and reads of reserved bits return zeros.  
Address: 0h 8005 0020  
UTSR1  
Read-Only  
Bit  
7
6
5
4
3
2
1
0
Reserved  
0
ROR  
0
FRE  
0
PRE  
TNF  
1
RNE  
0
TBY  
0
Reset  
0
0
Bit  
Name  
TBY  
Description  
0
Transmitter busy flag (read-only).  
0 – Transmitter is idle or UART is disabled.  
1 – Transmit logic is currently transmitting a frame (data within the serial shifter); no  
interrupt generated.  
1
2
3
RNE  
TNF  
PRE  
Receive FIFO not empty (read-only).  
0 – Receive FIFO is empty.  
1 – Receive FIFO is not empty (no interrupt generated).  
Transmit FIFO not full (read-only).  
0 – Transmit FIFO is full.  
1 – Transmit FIFO is not full (no interrupt generated).  
Parity error (read-only).  
0 – No parity errors encountered in the receipt of the next data value in the FIFO (or  
parity disabled).  
1 – Parity error encountered in the receipt of the next data value in the FIFO (no interrupt  
generated).  
4
5
FRE  
Framing error (read-only).  
0 – Stop bit for the next frame in the FIFO was a one.  
1– Stop bit for the next frame in the FIFO was a zero (no interrupt generated).  
ROR  
Receive FIFO overrun (read-only).  
0 – Receive FIFO has not experienced an overrun.  
1 – Receive logic attempted to place data into receive FIFO while it was full, the next  
data value in the FIFO is the last piece of “good” data before the FIFO was overrun (no  
interrupt generated).  
7..6  
Reserved.  
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11.11.9 UART Register Locations  
Table 11-18 shows the registers associated with serial port 3 and the physical addresses used to  
access them.  
Table 11-18. Serial Port 3 Control, Data, and Status Register Locations  
Address  
Name  
UTCR0  
Description  
UART control register 0  
0h 8005 0000  
0h 8005 0004  
0h 8005 0008  
0h 8005 000C  
0h 8005 0010  
0h 8005 0014  
0h 8005 0018  
0h 8005 001C  
0h 8005 0020  
UTCR1  
UTCR2  
UTCR3  
UART control register 1  
UART control register 2  
UART control register 3  
Reserved  
UTDR  
UART data register  
Reserved  
UTSR0  
UTSR1  
UART status register 0  
UART status register 1  
0h 8005 0024 –  
0h 8005 FFFF  
Reserved  
11.12  
Serial Port 4 – MCP / SSP  
Serial port 4 contains two separate full-duplex synchronous serial interfaces. The multimedia  
communications port (MCP) provides an interface to the Philips UCB1100 and UCB1200 codecs.  
Both devices have an audio codec, a telecom codec, a touch-screen interface, four general-purpose  
analog-to-digital converter inputs, and ten programmable digital I/O lines. The MCP interface is  
used by the SA-1100 both to input and output digital data to and from the codec, and to configure  
and acquire status information from the codecs’ 16 registers. The synchronous serial port (SSP) is  
used to interface to a variety of analog-to-digital converters, audio and telecom codecs, memory  
chips, and keypad controllers as well as other miscellaneous serial devices. The SSP supports the  
National Microwire and Texas Instruments* synchronous serial protocols as well as a subset of the  
Motorola* serial peripheral interface (SPI) protocol.  
In MCP mode, serial port 4 controls communication between the SA-1100 and either the UCB1100  
or UCB1200. The MCP produces two 64-bit subframes per frame (totalling 128 bits per frame)  
using a bit clock and frame synchronization signal. Data is communicated full-duplex via a  
separate transmit and receive data line. Selecting the on-chip clock, a bit clock frequency of either  
9.585 Mbps or 11.981 Mbps can be programmed. Alternatively, GPIO pin 21 can be used to input a  
bit clock from an off-chip source. This feature allows users to select a frame rate that is an exact  
multiple of the desired audio/telecom sample rate. The MCP communicates to the codec in the first  
of the two subframes. The second subframe is used in high-end applications to communicate with a  
second stereo codec; however, this feature is not supported by the MCP. Each 64-bit subframe  
contains seven different fields of information. These fields include: audio conversion data, telecom  
conversion data, data valid flags, control register address, control register data, and read/write  
control. Both transmit and receive data contains these seven fields. The transmit frame contains  
data for D-to-A conversion as well as address, data, and control signals to write to or read from the  
codec’s registers, and the receive frame contains A-to-D samples and the data returned from a read  
of a codec register.  
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Both the MCP and the off-chip codec contain programmable 7-bit divisors, one each for the  
telecom and audio data. These values are used to divide the bit clock to generate a desired sampling  
frequency. When the codec is enabled, the divisor pairs are synchronously transferred to their  
respective modulus registers within the MCP and off-chip codec, and decrement using the bit  
clock. This technique allows telecom and audio data to be transferred between the MCP and codec,  
lock-step in sync with the sampling/conversion frequency of the codec.  
The MCP contains two pairs of transmit FIFOs and two pairs of receive FIFOs, one each for audio  
and telecom data, totalling four separate 8-entry x 16-bit FIFOs. The MCP also contains a 21-bit  
data register used to transmit codec register reads and writes, as well as another 21-bit register to  
receive the results of codec register reads. Touch-screen and ADC conversions are triggered, the  
digital I/O lines are controlled using codec register writes, and the converted data and the state of  
digital I/O lines are accessed using a codec register read.  
In SSP mode, serial port 4 controls full-duplex synchronous serial transfers between the SA-1100  
and off-chip devices that support National Microwire*, Texas Instruments* synchronous serial, or  
the Motorola* SPI protocol. The SSP functions as a master only and communicates to the off-chip  
slave device by driving a serial bit rate clock ranging from 7.2 kHz to 1.8432 MHz along with a  
frame synchronization pulse to denote the start of each frame transfer, and supports any data format  
between 4 and 16 bits. Transmit and receive data is stored/collected using two separate  
8-entry x 16-bit FIFOs. MCP operation takes precedence over SSP operation. If use of both the  
MCP and SSP is required at the same time, the user can configure the SSP to take over control of  
GPIO pins 10 through 13, and the MCP uses the serial port 4 pins for transmission.  
The external pins dedicated to this interface are TXD4, RXD4, SCLK, and SFRM. If use of both  
the MCP and SSP is not required and serial port 4 is disabled, control of these pins is given to the  
peripheral pin controller (PPC) to be used to perform general-purpose input/output  
(noninterruptible). See the section 11.13 on page 184 for a description of the programming and  
operation of the PPC. The MCP operation takes precedence over the SSP if both units are enabled.  
Both the MCP and SSP support word reads/writes of their registers, and half-word DMA transfers  
to or from their FIFOs that are 16-bits wide.  
11.12.1 MCP Operation  
Following reset, both the MCP and SSP logic within serial port 4 is disabled and control of its pins  
is given to the PPC, which configures all four pins as inputs. To enable MCP operation, the  
programmer should first clear any interruptible status bits, which are set following the reset, by  
writing a one to them. Next, the user should program the MCP control register with the desired  
mode of operation using word writes, ensuring that the enable bit is programmed last. The user can  
choose to either “prime” the audio and telecom transmit FIFOs, before enabling the MCP, by  
writing up to eight 16-bit values each, or allow the FIFO service requests to interrupt the CPU or  
trigger a DMA transfer to fill the FIFOs. Once the off-chip codec is programmed and data resides  
within the bottom entries of the audio and/or telecom FIFOs, transmission/reception of data begins  
on the transmit (TXD4) and receive (RXD4) pins, and is synchronously controlled by the serial  
clock (SCLK) pin and a serial frame (SFRM) pin at a rate of 9.585 MHz or 11.981 MHz. The serial  
clock rate is selected by programming a control bit. Note that the two SCLK rates are derived by  
first multiplying the 3.6864-MHz on-chip oscillator by 13, then by dividing either by 5  
(9.58464 MHz) or by 4 (11.9808 MHz). Also note that an off-chip clock can be used to drive the  
MCP when a sample rate that is not a multiple of 3.6864 MHz is required.  
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11.12.1.1 Frame Format  
Each MCP data frame is 128 bits long and is divided into two subframes: 0 and 1. Subframe 0 is  
used by the MCP to communicate data to and from the UCB1100 or UCB1200. Subframe 1 is not  
used by the MCP because it is typically used to interface to high-performance stereo codecs such as  
Crystal’s CS4216/18.  
After the MCP is enabled, SCLK begins to transition at the programmed clock rate and the start of the  
first frame is signalled by pulsing the SFRM pin high for one SCLK period. The rising edge of SFRM  
coincides with the rising edge of SCLK. The SFRM pulse causes the MCP to transfer any available  
audio and/or telecom data from their respective transmit FIFOs to a 64-bit serial shifter, setting the  
appropriate audio/telecom valid flags as well. If the codec control register contains valid data, the  
register value and address are placed within the appropriate fields in the shifter, and the read/write bit  
is configured to indicate which type of register access is to be made. For any field that does not have  
valid data available, the previous value transmitted is used. As long as the MCP is enabled, data  
frames are continuously transferred, even if no valid data is available for transmission. The format of  
data transmitted and received in subframe 0 is shown in Figure 11-31. Note that the UCB110 or  
USB1200 data sheets use big-endian notation; little-endian notation is used in the following figure to  
remain consistent with the rest of the SA-1100 specification.  
Figure 11-31. MCP Frame Data Format  
3
1
1
6
1
5
63  
48  
47  
46  
43  
42  
41  
34  
33  
32  
0
Bit  
TX  
Audio Transmit Data  
Audio Receive Data  
0
Address  
R/W  
00000000  
AV TV Telecom Transmit Data  
Control Register Write  
RX  
0
Address  
R/W  
00000000  
AV TV Telecom Receive Data  
Control Register Read  
AV – Audio Data Valid TV Telecom Data Valid R/W – Write=1, Read=0 Address – Codec Register Address  
Both the MCP and the off-chip codec drive data on the rising edge of SCLK and latch data on its  
falling edge. After SFRM is negated, subframe 0 begins and the data within the 64-bit shifter is  
driven onto the TXD4 pin a bit at a time, starting with the MSB (bit<63>). As each bit of data is  
shifted onto the TXD4 pin from one side of the shifter, a bit is also shifted into the opposite end of  
the shifter from the RXD4 pin. After 64 SCLK cycles elapse, all data within the shifter has been  
transmitted, and the shifter contains the 64-bit receive data frame. The MCP takes the data from  
each field and places it in its respective receive FIFO or data register. The next 64 SCLK cycles  
make up subframe 1. When subframe 1 is active, the clocks to all MCP resources that are not  
needed are turned off in order to conserve power. Figure 11-32 shows the pin timing of the MCP.  
Figure 11-32. MCP Frame Pin Timing  
Frame Clock  
Count  
1
2
...  
63  
64  
65  
66  
...  
127  
128  
1
Subframe 0  
Subframe 1  
Subframe  
SCLK  
SFRM  
TXD4  
...  
...  
...  
Bit<63>  
Bit<63>  
Bit<62>  
Bit<62>  
...  
...  
Bit<1>  
Bit<1>  
Bit<0>  
Bit<0>  
...  
...  
Bit<63>  
Bit<63>  
RXD4  
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Note that the transmit line is pulled low any time data is not being driven onto the pin. The  
UCB1100 and UCB1200 have a programming option that allows them to either tristate or drive the  
receive line low when data is not being driven onto RXD4. As shown in Figure 11-32, MCP frames  
occur back-to-back. The SFRM pin is pulsed high during the last clock (128th) of the frame to  
indicate the start of a new frame the following SCLK period. Values contained within the transmit  
FIFOs are loaded to the shift register on the rising edge of SFRM.  
11.12.1.2 Audio and Telecom Sample Rates and Data Transfer  
The UCB1100 and UCB1200 contain both an audio and telecom codec with sample rates that can  
be individually programmed, and are derived from the programmed serial clock (SCLK) that is  
supplied by the MCP. For the audio codec, the sample rate is derived by dividing the serial clock  
first by a fixed value of 32, then by a value from 6 to 127. The same is true for the telecom codec,  
except that the programmable divisor ranges from 16 to 127. The codec and the MCP both contain  
an audio and a telecom sample rate counter. These counters are used to achieve conversion rate  
synchronization between the codec and MCP so that data may be coherently transferred between  
the MCP and the codec. For the remainder of this description, references made to the audio codec  
also apply to the telecom portion of the codec and MCP.  
Before enabling the audio codec, the audio sample rate counters within the codec and MCP must  
programmed with the same divisor value so that they have the same clock rate. The codec’s audio  
sample rate divisor is programmed by issuing a control register write transfer, and the MCP’s  
divisor is programmed using the CPU by writing to the MCP’s control register. Both the MCP and  
the codec’s audio counters are reloaded with the programmed modulus value any time the audio  
portion of the codec is enabled (which is also accomplished by performing a control register write  
transfer), or whenever the sample rate counters reach zero.  
The MCP and the audio codec decrement their counters in lock-step with one another, both starting  
on the occurrence of the first SFRM pulse after the audio codec is enabled. Samples/conversions  
are made each time the audio codec’s counter reaches zero. Figure 11-33 shows the timing of the  
audio codec enable and decrements of the MCP and audio codec’s sample counter.  
Figure 11-33. MPC/Codec Sampling Counter Synchronization  
Subframe  
SFRM  
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Ena  
Dis  
TXD4  
Audio Ena  
Counters  
Samp/Conv  
12....12  
12.11.10.9.8.7.6.5.4.3.2.1  
12.11.10.9.8.7.6.5.4.3.2.1  
12.11.10.9.8.7.6  
12...................12  
In the preceding figure, “Ena,” within the data frame on TXD4, represents a control register write to the  
codec to enable the input portion of the audio codec. The register is updated with the write at the end of  
subframe and the audio enable signal within the codec goes high. Both the MCP and codec’s audio  
sample rate counters then start to decrement on the next SFRM pulse. In the example, a divisor value of  
12 is used, causing the counter to decrement to zero after 384 (32*12=384) SCLK cycles occur.  
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If the input portion of the audio codec is enabled, when the counter reaches zero, a sample and  
A-to-D conversion is made and the converted value is placed within the correct field of the codec’s  
serial shift register for transmission back to the MCP in the next data frame. If the output portion of  
the audio codec is enabled, an audio data value is taken from the received data supplied by the  
MCP and is used for a D-to-A conversion. Data used in the D-to-A conversion is always taken  
from the previous MCP input frame. If no new data is available within the MCP’s audio transmit  
FIFO since the last D-to-A conversion, then the same data is used again (causing audio distortion).  
Samples and conversions occur twice in the preceding figure. However, while the counter is decrementing  
for the third time, the CPU disables the audio codec by issuing another control register write, represented  
by the “Dis” data frame on TXD4. The SFRM pulse following the write causes the disable to take effect,  
and the MCP and codec’s audio sample rate counters are stopped and reset to their modulus values.  
The MCP and the codec’s audio sample rate counters must be enabled coherently so that  
synchronization is achieved between the two. This is accomplished by first programming both the  
MCP and codec’s sample rate modulus values, then performing a codec control register write to  
enable the audio sampling rate counter within the codec. The MCP automatically decodes a write  
to the audio codec input and output enable bits, and enables the MCP’s audio sample rate counter at  
the same time as the codec’s counter to ensure synchronization.  
The UCB1100 and UCB1200 each have an individual data valid bit for audio and telecom A/D  
samples. Whenever these bits are set in the data frame returned from the codec to the MCP, the  
audio and telecom data is taken from the frame and placed in their respective receive FIFOs. The  
UCB1100 and UCB1200 have two different modes of operation to control the setting of the audio  
and telecom data valid bits. In the first mode, a data valid bit is set any time a frame contains  
“reliable” data ( the codec is enabled and at least one A-to-D sample has been taken). In this mode,  
once the data valid bit is set, it remains set until the codec A-to-D input is disabled. In the second  
mode, the codec only sets the data valid bit corresponding to a new A-to-D sample. Once the data  
is transmitted to the MCP within a receive data frame, the data valid bit is reset to zero for  
subsequent data frames until a new A-to-D sample is triggered.  
11.12.1.3 MCP Transmit and Receive FIFO Operation  
The MCP contains four 8-entry x 16-bit FIFOs: one for audio and one for telecom A-to-D samples  
received by the MCP, as well as one for audio and one for telecom D-to-A conversions transmitted  
to the codec. For the remainder of this description, references made to the audio codec also apply to  
the telecom portion of the codec and MCP.  
For each incoming data frame, if the audio data valid bit is set, the 16-bit audio A-to-D sample is  
extracted and placed in the audio receive FIFO. Note that the MCP also supports a mode in which  
the audio data valid bit is ignored after the first conversion has been saved to the FIFO, and the  
MCP’s audio sample rate counter is used to signal when a new A-to-D sample has been taken and  
is available within the incoming frame. Audio data is transferred from the incoming data frames to  
the receive FIFO only if the audio enable bit is set within the MCP’s status register.  
The MCP’s audio and telecom sample rate counters are used to trigger when new D/A conversions  
are to be transmitted to the codec. The user should take care in ensuring sample rate counters in the  
MCP are synchronized with the respective sample rate counters in the codec as described in  
preceding sections. When the audio enable status bit transitions from a 0 to a 1 within the MCP status  
register, the next available entry of data is taken from the audio transmit FIFO and is placed within the  
correct field in the MCP’s serial shifter. This value is then continuously transferred by the MCP in  
each data frame to the codec. The codec uses the value only when its audio sample rate counter  
decrements to zero. After the audio D-to-A conversion is made, both the codec and the MCP’s audio  
sample rate counters reload with their modulus values. This reload triggers the audio transmit FIFO to  
transfer the next available entry of data to the MCP’s serial shifter. Again, this value is continuously  
transmitted to the codec in each data frame until it is used in the next audio D-to-A conversion.  
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The width of each entry within the audio and telecom FIFOs is 16 bits. However, the audio codec’s  
sample/conversion data size is 12 bits and the telecom is 14 bits. Conversions and samples are left  
justified within the 16-bit audio and telecom data fields in the MCP frame as well as within the  
transmit and receive FIFOs. Figure 11-34 shows the required data alignment for the transmit and  
receive audio and telecom FIFOs. The user must left justify data to be transmitted, and shift  
received data to the right before using the results.  
Figure 11-34. Audio/Telecom Transmit/Receive FIFO Data Format  
Bit  
Bit  
15  
15  
14  
14  
13  
13  
12  
12  
11  
11  
10  
9
8
8
7
7
6
6
5
5
4
4
3
0
2
0
1
0
0
0
Audio Data  
10  
9
3
2
1
0
0
0
Telecom Data  
To reduce chip size as well as power consumption, the MCP’s FIFOs use self-timed logic (not  
clocked). Because of process and environmental variations, the depth at which a service request is  
triggered to empty the receive FIFOs is variable. This variation spans a maximum of four FIFO  
entries, thus the audio and telecom receive FIFO service requests can be made at four different  
FIFO depths.To compensate for this variability and guarantee that at least four valid entries of data  
exist within either FIFO before generating a service request, an extra four entries have been added  
to both receive FIFOs (four entries more than the transmit FIFOs). Thus the audio and telecom  
transmit FIFOs are 8-entries deep and the audio and telecom receive FIFOs are 12-entries deep.  
The point at which the receive FIFO service requests are triggered spans one-third (four entries) of  
the 12-entry FIFOs. The service request is signalled at a depth from one-third full to two-thirds full  
(when the FIFOs contains five, six, seven, or eight entries of data).  
11.12.1.4 Codec Control Register Data Transfer  
The UCB1100 and UCB1200 contain sixteen 16-bit registers used to configure the chip, and store  
touch-screen and ADC samples as well as digital I/O pin state and edge interrupt status. These  
registers are read and written via the MCP’s serial interface using three fields that exist within the  
MCP’s data frame. In Figure 11-31, bits 15:0 contain the value read from or written to the off-chip  
codec, bits 46:43 contain the register address of the current read or write, and bit 42 is used by the  
MCP to signal a read or write cycle to the codec. These fields are configured by the CPU by writing  
to MCP control register 2, and are then transmitted to the off-chip codec. These fields are also  
received every data frame by the MCP from the codec and are placed in MCP control register 2,  
which can be read by the CPU. Note that the contents of the addressed register are returned in the  
receive data frame regardless of the state of the read/write bit. Thus for write cycles, both a write  
and a read occurs, and for read cycles, only a read occurs.  
A register write is performed by writing a value to the MCP control register 2 that contains the  
value to store to the register, the address of the register, and the read/write bit set to one. Once this  
register is written, its contents are transferred to the correct fields within the serial shifter on the  
next rising edge of the SFRM signal. The register information is transmitted to the UCB1100 or  
UCB1200 during subframe 0, and the value is written to the selected codec register at the end of  
subframe 0 (during the 65th bit of the frame). The control register value and address are also  
returned to the MCP and stored in MCP control register 2. The read/write bit is zero in the return  
frame. Because the addressed register is updated at the end of subframe 0, the data returned during  
the frame in which the write occurred represents the previous contents of the register. The updated  
value is returned during the next data frame.  
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A register read is performed by writing a value to MCP data register 2 that contains the address of  
the register and the read/write bit set to a zero. Again, the data is transferred to the serial shifter on  
the next rising edge of the SFRM signal and is transmitted to the UCB1100 or UCB1200 during  
subframe 0. Because the address and read/write control bit fields occur near the beginning of the  
serial stream output, the codec performs the read immediately after the read/write bit is received  
(during the 41st bit of the frame) and the value contained within the addressed register is sent back  
to the MCP in the same data frame.  
Once the codec control register is written with a value to execute a read or write, the operation is  
performed every MCP data frame until a new value is written to the register. Thus, continual reads  
or writes are made to the addressed codec register until a new read or write operation is configured.  
11.12.1.5 External Clock Operation  
Under normal operation, the MCP is programmed to use one of two on-chip clocks to produce a  
9.585-Mbps or 11.981-Mbps bit rate. This clock is also used to increment the audio and telecom  
sample rate counters. The MCP also supports a special mode that allows the user to control the  
MCP’s frame rate and audio/telecom sample rates. This mode is useful when sample rates that are  
not an integer multiple of 12 MHz are required. In this mode, the MCP uses GPIO<21> to input a  
clock supplied from off-chip. The frequency of the off-chip clock can be any value within the  
allowable frequency range of the UCB100, up to 12 MHz. When using GPIO pin 21 for the input  
clock, the user must also set bit 21 of the GPIO alternate function register (GAFR) and clear bit 21  
of the GPIO pin direction register (GPDR). See the Section 9.1, “General-Purpose I/O” on  
11.12.1.6 Alternate SSP Pin Assignment  
MCP operation takes precedence over SSP operation. Thus if both are enabled, serial port 4  
defaults to MCP mode. However, if the MCP and SSP both need to be used at the same time,  
general-purpose I/O pins 10..13 (GPIO<10..13>) can be reassigned by programming the PPC pin  
assignment register (PPAR). This allows the MCP dedicated use of the four pins assigned to serial  
port 4, and the SSP dedicated use of the GPIO pins. When the SSP pin reassignment (SPR) bit is  
set in PPAR, the following pin assignments are made: GPIO<10> is used for transmit, GPIO<11>  
for receive, GPIO<12> for serial clock, and GPIO<13> for serial frame. Note that the user must  
also set bits 10 through 13 in the GPIO alternate function register (GAFR) as well as set bits 10, 12,  
and 13, and clear bit 11 in the GPIO pin direction register (GPDR). Once the reassignment is made,  
these pins are no longer usable by the GPIO unit. See the Section 9.1, “General-Purpose I/O” on  
page 9-1 for a description of how to program the system control module and the Section 11.13,  
“Peripheral Pin Controller (PPC)” on page 11-184 for a description of how to program the PPC  
unit.  
11.12.1.7 CPU and DMA Register Access Sizes  
Bit positioning and addressing of the MCP is described in terms of little endian ordering. All MCP  
registers are 32 bits wide. The ARM peripheral bus does not support byte or half-word operations.  
All reads and writes of the MCP by the CPU should be wordwide. Four separate dedicated DMA  
requests exist for the audio and telecom transmit and receive FIFOs. If the DMA controller is used  
to service the transmit and/or receive FIFOs, the user must ensure the DMA is properly configured  
to perform half-word accesses, using 4 half-words per burst (half the size of the FIFOs). Note that a  
separate set of registers also exist to configure SSP operation. See the following sections for a full  
description of programming and operation of serial port 4 as an SSP, a summary of serial port 4’s  
MCP registers, and a summary of its SSP registers.  
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11.12.2 MCP Register Definitions  
There are six registers within the MCP: two control registers, three data registers, and one status  
register. The control register is used to program the audio and telecom sample rates, to mask or  
unmask interrupt requests to service the MCP’s FIFOs, to select whether an on-chip or off-chip clock  
is used to drive the bit rate, and to enable/disable operation. The first data register addresses the top of  
the audio transmit FIFO and the bottom of the audio receive FIFO. Likewise, the second data register  
addresses the top/bottom of the telecom transmit/receive FIFOs, respectively. A read accesses the  
receive FIFOs; a write accesses the transmit FIFOs. Note that these are four physically separate  
FIFOs to allow full-duplex transmission. The third data register is 21 bits and is used to transmit read  
and write operations to the codec’s control, data, and status registers. Values written to the register are  
used in the transmit data frame and values read are taken from the received data frame. The status  
register contains bits that signal FIFO overrun and underrun errors, and transmit and receive FIFO  
service requests. Each of these status conditions signals an interrupt request to the interrupt controller.  
The status register also flags when audio and telecom transmit FIFOs are not full, when the audio and  
telecom receive FIFOs are not empty, when a codec control register read or write is complete, and  
when the audio or telecom portion of the codec is enabled (no interrupt generated).  
11.12.3 MCP Control Register  
The MCP control register (MCCR) contains 11 different bit fields that control various functions  
within the MCP.  
11.12.3.1 Audio Sample Rate Divisor (ASD)  
The 7-bit audio sample rate divisor (ASD) bit field is used to synchronize the MCP with the sample  
rate of the audio codec. Sample rate synchronization is required such that the MCP’s audio transmit  
FIFO logic knows when to load a new value for D-to-A conversion to the MCP’s serial shifter for  
transmission. This field is programmed with the same value that is written to the codec’s sample  
rate divisor via a codec control register write. When the audio codec is enabled, the first audio  
transmit value is placed in the serial output stream by the transmit FIFO, and both the MCP’s and  
codec’s sample rate counters begin to decrement in lock-step with one another. When the audio  
codec’s counter decrements to zero, it uses the value transmitted to it by the MCP to perform the  
D-to-A conversion. After the conversion is made, the MCP and codec’s counters reset to their  
modulus values, and the MCP’s audio transmit FIFO loads the next value to the serial shifter for  
transmission. This new value is then transmitted to the audio codec and is used for the next D-to-A  
conversion, which is signalled when the sample rate counter decrements to zero again.  
A total of 122 different audio sample rates can be selected, ranging from a minimum of 2.358 K  
samples per second using the 9.585-MHz internal clock to a maximum of 62.401 K samples per  
second using the 11.981-MHz internal clock. Note that slower sample rates can be achieved using  
an externally supplied clock. The sample rate clock generator uses either a 9.585-MHz or  
11.981-MHz clock produced by the on-chip PLL or the clock supplied to the MCP via GPIO  
pin 21, and is divided by a fixed value of 32 and then by the programmable ASD value to generate  
the audio sample clock. This clock is automatically enabled when:  
A codec control register write to the audio control register B is made (address=0b100), which  
sets either the audio codec input or output enable bits (bit 14 = aud_in_ena, bit 15 =  
aud_out_ena), followed by  
The rising edge of the next SFRM pulse after the write has been made.  
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Once enabled, the MCP’s audio sample rate clock decrements at the programmed frequency with a 50%  
duty cycle. The action outlined in the above first bullet item causes the MCP’s audio transmit FIFO logic  
to transfer the next available value to the audio data field within the serial shifter. Each time the audio  
sample rate clock decrements to zero, it is reloaded with its programmed ASD modulus value, triggers  
the audio transmit FIFO logic to transfer the next available value to the audio data field within the serial  
shifter, and continues to decrement. The MCP’s audio sample rate clock is automatically disabled when:  
A codec control register write to the audio control register B is made (address=0b100), which  
clears both the audio codec input and output enable bits (bit 14 = aud_in_ena, bit 15 =  
aud_out_ena), followed by  
The rising edge of the next SFRM pulse after the write has been made.  
The resultant audio sample clock rate, given a specific ASD value, can be calculated using the following  
equation, where ASD is the decimal equivalent of the binary value programmed within the bit field. Note  
that ASD must be programmed with a value of 6 or larger. Unpredictable results occur for ASD values  
smaller than 6. Note that one of three clock frequencies can be selected. The first two frequencies are  
internal clocks selected by the CFS bit in MCCR1 and the third frequency is a user-defined clock that is  
input via GPIO pin 21 and is divided as defined by the ECP bit field described in following sections.  
6
12×10  
SampleRate = -----------------------  
32xASD  
Valid ASD values are from 6 (00000110) to 127 (11111111)  
6
Note: The 12x10 value within the formula’s numerator should be replaced with the frequency  
of the clock driven to GPIO pin 21 when an off-chip clock source is used to drive the MCP.  
11.12.3.2 Telecom Sample Rate Divisor (TSD)  
The 7-bit telecom sample rate divisor (TSD) bit field is used to synchronize the MCP with the  
sample rate of the telecom codec. The telecom sample rate clock is required for the same reason  
and works exactly like the audio sample rate clock, except for one minor difference. The valid TSD  
values range from 16 to 127 (instead of 6), allowing a total of 112 different audio sample rates to be  
selected, ranging from a minimum of 2.358 K samples per second using the 9.585-MHz internal  
clock to a maximum of 23.400 K samples per second using the 11.98-MHz internal clock. Note  
that slower sample rates can be achieved using an externally supplied clock.  
The resultant telecom sample clock rate, given a specific TSD value, can be calculated using the  
following equation, where TSD is the decimal equivalent of the binary value programmed within  
the bit field. Note that TSD must be programmed with a value of 16 or larger. Unpredictable results  
occur for TSD values smaller than 16. Note that one of three clock frequencies can be selected. Thr  
first two frequencies are internal clocks selected by the CFS bit in MCCR1 and the third frequency  
is a user-defined clock that is input via GPIO pin 21 and is divided by the ECP bit field described in  
the following sections.  
6
12×10  
SampleRate = -----------------------  
32xTSD  
Valid TSD values are from 16 (00010000) to 127 (11111111)  
6
Note: The 12x10 value within the formula’s numerator should be replaced with the frequency of  
the clock driven to GPIO pin 21 when an off-chip clock source is used to drive the MCP.  
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11.12.3.3  
Multimedia Communications Port Enable (MCE)  
The MCP enable (MCE) bit is used to enable and disable all MCP operation. Since the MCP and  
SSP both share the same pins, only one can be enabled at a time. If the user enables both at the  
same time, the MCP has precedence and the SSP remains disabled. However, both can be enabled  
when the SSP pin reassignment (SPR) bit within the PPC unit is set, which assigns the SSP to  
GPIO pins. See the following sections for a description of the SSP enable (SSE) bit.  
When the MCP is disabled, all of its clocks are powered down to minimize power consumption. If  
the SSP is also disabled, the TXD4, RXD4, SCLK, and SFRM pins can be used for  
page 11-184 for a description of how to program the PPC unit to reassign the SSP’s pins and to use  
serial port 4’s pins as I/Os. Note that MCE and CFS are the only control bits within the MCP that  
are reset to a known state. MCE is cleared to zero to ensure the MCP is disabled following a reset  
of the SA-1100.  
When the MCP is enabled, SCLK begins to transition and the start of the first frame is signalled by  
pulsing the SFRM pin high for one SCLK period. The rising edge of SFRM coincides with the  
rising edge of SCLK. As long as the MCE bit is set, the MCP operates continuously, transmitting  
and receiving 128 bit data frames. When the MCE bit is cleared, the MCP is disabled immediately,  
causing the current frame, which is being transmitted, to be terminated and control of serial port 4’s  
pins to be given to the PPC unit. Clearing MCE resets the MCP’s FIFOs. However, MCP data  
register 3, the control, and the status registers are not reset. The user must ensure these registers are  
properly reconfigured before reenabling the MCP.  
11.12.3.4 External Clock Select (ECS)  
The external clock select (ECS) bit selects whether one of the two on-chip clocks derived by the  
3.6864-MHz oscillator is used by the MCP or if an off-chip clock is supplied via GPIO pin 21.  
When ECS=0, the MCP can be programmed to select one of two frequencies: either 9.585 MHz or  
11.981 MHz. This clock is also used to increment the audio and telecom sample rate counters. (See  
preceding sections.) When ECS=1, the MCP uses GPIO<21> to input a clock supplied from  
off-chip. The frequency of the off-chip clock after being scaled by the ECP bit field can be any  
value within the allowable frequency range of the UCB100 up to 12 MHz. This off-chip clock is  
useful when a sample rate frequency, which is not a multiple of 9.585 MHz or 11.981 MHz is  
required for synchronization with either the audio and/or telecom portion of the UCB1100 or  
UCB1200 codecs. When using GPIO pin 21 for the input clock, the user must also set bit 21 of the  
GPIO alternate function register (GAFR) and clear bit 21 of the GPIO pin direction register  
11.12.3.5 A/D Sampling Mode (ADM)  
The A/D sampling mode (ADM) bit selects whether the MCP takes audio and telecom data from  
the incoming frame only when their respective data valid bits are set or whenever the MCP’s audio  
and telecom sample rate counters time-out, indicating that the data in the next incoming frame is  
valid. When ADM=0, data is taken from the incoming frame and is placed into the audio or  
telecom FIFO whenever the incoming audio or telecom data valid bit is set. When ADM=1, after  
the MCP is enabled, data is taken from the incoming frame when the data valid bit is set for the  
first time. After this point, the data valid bit is ignored, and samples are stored each time the audio  
or telecom sample rate counters decrement to zero, indicating that a new A-to-D sample was taken  
and will be available in the next frame.  
The UCB1100 and UCB1200 have two different modes of operation to control the setting of the  
audio and telecom data valid bits. In one mode, the codec only sets the data valid bit when a new  
A-to-D sample is contained within the incoming data frame. Once the data is transmitted to the  
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MCP within a receive data frame, the data valid bit is reset to zero for subsequent data frames until  
a new A-to-D sample is triggered and transmitted to the MCP. In this mode, the user should  
program ADM=0. In the other mode, the data valid bit is set once when the first A-to-D conversion  
is made and is placed in the receive data frame. However, the data valid bit remains set and the  
MCP cannot determine when new A-to-D conversions are available within the incoming frame.  
Programming ADM=1 prevents multiple copies of the same A-to-D conversion to be placed in the  
FIFO, storing samples only when the sample rate counter times out.  
11.12.3.6 Telecom Transmit FIFO Interrupt Enable (TTE)  
The telecom transmit FIFO interrupt enable (TTE) bit is used to mask or enable the telecom  
transmit FIFO service request interrupt. When TTE=0, the interrupt is masked and the state of the  
telecom transmit FIFO service request (TTS) bit within the MCP status register is ignored by the  
interrupt controller. When TTE=1, the interrupt is enabled, and whenever TTS is set (one), an  
interrupt request is made to the interrupt controller. Note that programming TTE=0 does not affect  
the current state of TTS or the telecom transmit FIFO logic’s ability to set and clear TTS; it only  
blocks the generation of the interrupt request. Also note that TTE does not affect generation of the  
telecom transmit FIFO DMA request, which is asserted any time TTS=1.  
11.12.3.7 Telecom Receive FIFO Interrupt Enable (TRE)  
The telecom receive FIFO interrupt enable (TRE) bit is used to mask or enable the telecom receive  
FIFO service request interrupt. When TRE=0, the interrupt is masked, and the state of the telecom  
receive FIFO service request (TRS) bit within the MCP status register is ignored by the interrupt  
controller. When TRE=1, the interrupt is enabled, and whenever TRS is set (one), an interrupt  
request is made to the interrupt controller. Note that programming TRE=0 does not affect the  
current state of TRS or the telecom receive FIFO logic’s ability to set and clear TRS; it only blocks  
the generation of the interrupt request. Also note that TRE does not affect generation of the telecom  
receive FIFO DMA request, which is asserted any time TRS=1.  
11.12.3.8 Audio Transmit FIFO Interrupt Enable (ATE)  
The audio transmit FIFO interrupt enable (ATE) bit is used to mask or enable the audio transmit  
FIFO service request interrupt. When ATE=0, the interrupt is masked and the state of the audio  
transmit FIFO service request (ATS) bit within the MCP status register is ignored by the interrupt  
controller. When AT=1, the interrupt is enabled, and whenever ATS is set (one), an interrupt  
request is made to the interrupt controller. Note that programming ATE=0 does not affect the  
current state of ATS or the audio transmit FIFO logic’s ability to set and clear ATS; it only blocks  
the generation of the interrupt request. Also note that ATE does not affect generation of the audio  
transmit FIFO DMA request, which is asserted any time ATS=1.  
11.12.3.9 Audio Receive FIFO Interrupt Enable (ARE)  
The audio receive FIFO interrupt enable (ARE) bit is used to mask or enable the audio receive  
FIFO service request interrupt. When ARE=0, the interrupt is masked, and the state of the audio  
receive FIFO service request (ARS) bit within the MCP status register is ignored by the interrupt  
controller. When ARE=1, the interrupt is enabled, and whenever ARS is set (one), an interrupt  
request is made to the interrupt controller. Note that programming ARE=0 does not affect the  
current state of ARS or the audio receive FIFO logic’s ability to set and clear ARS; it only blocks  
the generation of the interrupt request. Also note that ARE does not affect generation of the audio  
receive FIFO DMA request, which is asserted any time ARS=1.  
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Peripheral Control Module  
11.12.3.10 Loopback Mode (LBM)  
The loopback mode (LBM) bit is used to enable and disable the ability of the MCP’s transmit and  
receive logic to communicate. When LBM=0, the MCP operates normally. The transmit and  
receive data paths are independent and communicate via their respective pins. When LBM=1, the  
output of the serial shifter (MSB) is directly connected to the input of the serial shifter (LSB)  
internally and control of the TXD4, RXD4, SCLK, and SFRM pins are given to the peripheral pin  
control (PPC) unit.  
11.12.3.11 External Clock Prescaler (ECP)  
The 2-bit external clock select (ECP) field is used to divide the clock input via GPIO pin 21 when  
the external clock function is enabled. When ECS=1, ECP is decoded to divide the clock input on  
the GPIO<21> pin by 1, 2, 3, or 4 before being used to drive the MCP’s frame rate. When  
ECP=00, the input clock is divided by 1; when ECP=01, it is divided by 2; when ECP=10, it is  
divided by 3; and when ECP=11, it is divided by 4. Note that the ECP bit field is ignored when the  
internal clock (ECS=0) is used to drive the MCP’s frame rate. Also note that the resultant clock  
frequency after the divide has taken place can be any value within the allowable frequency range of  
the UCB1100 or UCB1200 (up to 12 MHz).  
The following table shows the bit locations corresponding to the 10 different control bit fields  
within the MCP control register. Note that the MCE bit is the only control bit that is reset to a  
known state to ensure the MCP is disabled following a reset of the SA-1100. The reset state of all  
other control bits is unknown (indicated by question marks) and must be initialized before enabling  
the MCP. The user can program all 11 bit fields and enable the MCP using a single word write to  
MCCR0. Writes to reserved bits are ignored and reads return zeros.  
Address: 0h 8006 0000  
31 30  
Reserved  
MCP Control Register 0: MCCR  
Read/Write  
Bit  
29  
0
28  
0
27  
0
26  
0
25  
24  
23  
22  
21  
ATE  
?
20  
19  
TTE  
?
18  
17  
16  
ECP  
0
LBM  
?
ARE  
?
TRE  
?
ADM  
?
ECS  
?
MCE  
0
Reset  
0
0
0
Bit  
15  
14  
TSD  
?
13  
?
12  
?
11  
?
10  
?
9
?
8
7
6
5
?
4
?
3
?
2
?
1
?
0
?
Res.  
0
Res.  
0
ASD  
?
Reset  
?
Bit  
Name  
Description  
6..0  
ASD  
Audio sample rate divisor.  
Value (from 6 to 127) used to match the sample rate of the audio codec within the UCB1100  
or UCB1200 to time when audio D/A data should be supplied by the audio transmit FIFO.  
Sample Rate = Programmed clock rate/(32xASD), where ASD is a decimal value.  
7
Reserved.  
14..8  
TSD  
Telecom sample rate divisor.  
Value (from 16 to 127) used to match the sample rate of the telecom codec within the  
UCB1100 or UCB1200 to time when telecom D/A data should be supplied by the telecom  
transmit FIFO.  
Sample Rate = Programmed clock rate/(32xTSD), where TSD is a decimal value.  
Reserved.  
15  
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Peripheral Control Module  
Bit  
16  
Name  
Description  
Multimedia communications port enable.  
MCE  
0 – MCP operation disabled, control of the TXD4, RXD4, SCLK, and SFRM pins given to the  
PPC to be used as general-purpose I/O pins.  
1 – MCP operation enabled.  
Note that the MCP has precedence over the SSP, if MCE=1; SSE is ignored unless the SPR  
bit is set within the PPC, which allows the SSP to use GPIO pins while the MCP uses serial  
port 4’s pin for transmission.  
17  
ECS  
External clock select.  
0 – on-chip clock used to produce the frame rate as further programmed by the CFS control  
bit in MCCR1. It is also used to clock the audio and telecom sample rate counters.  
1 – Clock input using GPIO pin 21 to select a frame rate that is an exact multiple of the  
desired audio/telecom sample rate.  
Frame Rate = Input Clock Freq /(ECP x 32).  
Sample Rate = Input Clock Freq /(ECP x 32 x ASD or TSD).  
18  
19  
20  
21  
22  
23  
ADM  
TTE  
TRE  
ATE  
ARE  
LBM  
A/D data sampling mode.  
0 – Audio and telecom receive data is stored to their respective FIFOs whenever their receive  
data valid bits are valid.  
1– Audio and telecom receive data is stored when the receive data valid bit is set the first time,  
and from that point on whenever the MCP’s audio and telecom sample rate counters time out.  
Telecom transmit FIFO interrupt enable.  
0 – Telecom transmit FIFO half-full or less condition does not generate an interrupt (TTS bit  
ignored).  
1 – Telecom transmit FIFO half-full or less condition generates an interrupt (state of TTS  
sent to interrupt controller).  
Telecom receive FIFO interrupt enable.  
0 – Telecom receive FIFO one- to two-thirds full or more condition does not generate an  
interrupt (TRS bit ignored).  
1 – Telecom receive FIFO one- to two-thirds full or more condition generates an interrupt  
(state of TRS sent to interrupt controller).  
Audio transmit FIFO interrupt enable.  
0 – Audio transmit FIFO half-full or less condition does not generate an interrupt (ATS bit  
ignored).  
1 – Audio transmit FIFO half-full or less condition generates an interrupt (state of ATS sent to  
interrupt controller).  
Audio receive FIFO interrupt enable.  
0 – Audio receive FIFO one- to two-thirds full or more condition does not generate an  
interrupt (ARS bit ignored).  
1 – Audio receive FIFO one- to two-thirds full or more condition generates an interrupt (state  
of ARS sent to interrupt controller).  
Loopback mode.  
0 – Normal serial port operation enabled.  
1 – Output of serial shifter is connected to input of serial shifter internally and control of  
TXD4, RXD4, SCLK, and SFRM pins is given to the PPC unit.  
25..24 ECP  
External clock prescaler.  
00 – Clock input using GPIO pin 21 is divided by one before being used to drive the frame rate.  
00 – Clock input using GPIO pin 21 is divided by two before being used to drive the frame rate.  
00 – Clock input using GPIO pin 21 is divided by three before being used to drive the frame rate.  
00 – Clock input using GPIO pin 21 is divided by four before being used to drive the frame rate.  
Note: ECP is used only when ECS=1. Also, the maximum clock frequency allowed to drive  
the frame rate after ECS has divided down the input clock is 12 MHz.  
31.. 26  
Reserved.  
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Peripheral Control Module  
11.12.4 MCP Control Register 1  
The MCP control register 1 (MCCR1) contains one bit that selects one of two fixed frequencies to  
drive the MCP. Note that this register resides within the PPC’s address space.  
11.12.4.1 Clock Frequency Select (CFS)  
When the on-chip clock is enabled (ECS=0), the clock frequency select (CFS) bit is used to select  
either a 9.585-MHz or an 11.981-MHz clock to drive the MCP’s serial clock rate. When ECS=0  
and CFS=0, the on-chip 3.6864-MHz oscillator is first multiplied by 13 then divided by 4, resulting  
in an 11.9808-MHz bit clock frequency. When ECS=0 and CFS=1, the on-chip 3.6864 MHz  
oscillator is first multiplied by 13 then divided by 5, resulting in a 9.58464-MHz bit clock  
frequency. Note that when ECS=1, CFS is ignored and an external clock is input to the MCP via  
GPIO pin 21. Also note that CFS is cleared following a reset of the SA-1100 so that the MCP  
defaults to 11.981-MHz operation, which is standard for the UCB1100/1200.  
The following table shows the location of the CFS control bit within the MCP control register 1.  
The CFS is cleared to zero selecting 11.981-MHz operation following a reset of the SA-1100.  
Writes to reserved bits are ignored and reads return zeros. MCCR1 resides within the PPC’s  
address space.  
Address: 0h 9006 0030  
MCP Control Register 1: MCCR1  
Read/Write  
Bit  
Reset  
Bit  
31  
30  
29  
0
28  
0
27  
0
26  
Reserved  
0
25  
24  
23  
22  
21  
0
20  
CFS  
0
19  
0
18  
0
17  
16  
0
Reserved  
0
0
0
0
0
0
0
1
0
15  
0
14  
0
13  
0
12  
0
11  
0
10  
0
9
8
7
6
5
4
0
3
2
0
Reserved  
0
Reset  
Bit  
0
0
0
0
0
0
0
Name  
Description  
19..0  
Reserved.  
Clock frequency select.  
20  
CFS  
0 – If ECS=0, bit rate clock frequency of 11.981 MHz is selected.  
1 – If ECS=0, bit rate clock frequency of 9.585 MHz is selected.  
If ECS=1, CFS is ignored and an external clock supplied by GPIO pin 21 is used.  
31..21  
Reserved.  
11.12.5 MCP Data Registers  
The MCP contains three data registers. MCDR0 addresses the top entry of the audio transmit FIFO  
and bottom entry of the audio receive FIFO, MCDR1 addresses the top and bottom entries of the  
telecom transmit and receive FIFOs respectively, and MCDR2 is used to perform reads and writes  
to any of the codec’s 16 registers via the MCP’s serial interface.  
11-158  
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Peripheral Control Module  
11.12.5.1 MCP Data Register 0  
When MCP data register 0 (MCDR0) is read, the bottom entry of audio receive FIFO is accessed.  
As data is removed by the MCP’s receive logic from the incoming data frame, it is placed into the  
top entry of the audio receive FIFO and is transferred down an entry at a time until it reaches the  
last empty location within the FIFO. Data is removed by reading MCDR, which accesses the  
bottom entry of the audio FIFO. After MCDR0 is read, the bottom entry is invalidated and all  
remaining values within the FIFO automatically transfer down one location.  
When MCDR0 is written, the topmost entry of the audio transmit FIFO is accessed. After a write,  
data is automatically transferred down to the lowest location within the transmit FIFO, which does  
not already contain valid data. Data is removed from the bottom of the FIFO one value at a time by  
the transmit logic, is loaded into the correct position within the 64-bit transmit serial shifter, and  
then is serially shifted out onto the TXD4 pin during subframe 0.  
Audio data is 12 bits wide and must be left justified by the user before writing it to the transmit FIFO  
(MSB of audio data corresponds to bit 16 of transmit FIFO). The lower four bits of the FIFO are  
automatically zero filled by the transmit logic when a 16-bit value is written to MCDR0 for  
transmission. The UCB1100 or UCB1200 automatically forces bits 0 through 3 to zero before  
transmitting the value to the MCP. The user must right justify received audio data before using it.  
The following table shows MCDR0. Note that the transmit and receive audio FIFOs are cleared  
when the SA-1100 is reset or by writing a zero to MCE (MCP disabled). Also note that writes to  
reserved bits are ignored and reads return zeros.  
Address: 0h 8006 0008  
MCP Data Register 0: MCDR0  
Read/Write  
Bit  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
Reset  
Bit  
0
0
0
0
0
0
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
0
0
2
0
0
0
1
0
0
0
0
0
0
15  
14  
13  
12  
11  
10  
Bottom of Audio Receive FIFO  
Reset  
Bit  
0
0
0
0
0
0
0
0
0
0
0
0
Read Access  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
Reset  
Bit  
0
0
0
0
0
0
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
0
0
2
0
0
0
1
0
0
0
0
0
0
15  
14  
13  
12  
11  
10  
Top of Audio Transmit FIFO  
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
Write Access  
Bit  
Name  
Description  
3..0  
Reserved for future enhancements.  
Read – Data returned, but UCB1100 and UCB1200 currently zero fill these four bits.  
Write – MCP’s transmit logic automatically zero fills these bits.  
15..4  
Audio  
Data  
Transmit/receive audio FIFO data.  
Read – Bottom of audio receive FIFO data.  
Write – Top of audio transmit FIFO data.  
31..16  
Reserved.  
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Peripheral Control Module  
11.12.5.2 MCP Data Register 1  
When MCP data register 1 (MCDR1) is read, the bottom entry of the telecom receive FIFO is  
accessed. As data is removed by the MCP’s receive logic from the incoming data frame, it is placed  
into the top entry of the telecom receive FIFO and is transferred down an entry at a time until it  
reaches the last empty location within the FIFO. Data is removed by reading MCDR1, which  
accesses the bottom entry of the telecom FIFO. After MCDR1 is read, the bottom entry is  
invalidated, and all remaining values within the FIFO automatically transfer down one location.  
When MCDR1 is written, the topmost entry of the telecom transmit FIFO is accessed. After a  
write, data is automatically transferred down to the lowest location within the transmit FIFO,  
which does not already contain valid data. Data is removed from the bottom of the FIFO one value  
at a time by the transmit logic, is loaded into the correct position within the 64-bit transmit serial  
shifter, and then is serially shifted out onto the TXD4 pin during subframe 0.  
Telecom data is 14 bits wide and must be left justified by the user before writing it to the transmit  
FIFO (MSB of telecom data corresponds to bit 16 of transmit FIFO). The lower two bits of the FIFO  
are automatically zero filled by the transmit logic when a 16-bit value is written to MCDR1 for  
transmission. The UCB1100 or UCB1200 automatically forces bits 0 and 1 to zero before  
transmitting the value to the MCP. The user must right justify received telecom data before using it.  
The following table shows MCDR1. Note that the transmit and receive telecom FIFOs are cleared  
when the SA-1100 is reset, or by writing a zero to MCE (MCP disabled). Also note that writes to  
reserved bits are ignored and reads return zeros.  
Address: 0h 8006 000C  
MCP Data Register 1: MCDR1  
Read/Write  
Bit  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
Reset  
Bit  
0
0
0
0
0
0
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
0
0
0
15  
14  
13  
12  
11  
10  
Bottom of Telecom Receive FIFO  
Reset  
Bit  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Read Access  
31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
Reserved  
Reset  
Bit  
0
0
0
0
0
0
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
0
0
0
15  
14  
13  
12  
11  
10  
Top of Telecom Transmit FIFO  
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Write Access  
Bit  
Name  
Description  
1..0  
Reserved for future enhancements.  
Read – Data returned, but UCB1100 or UCB1200 currently zero fills these two bits.  
Write – MCP’s transmit logic automatically zero fills these bits.  
15..2  
Telecom  
Data  
Transmit/receive telecom FIFO data.  
Read – Bottom of telecom receive FIFO data.  
Write – Top of telecom transmit FIFO data.  
31..16  
Reserved.  
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Peripheral Control Module  
11.12.5.3 MCP Data Register 2  
MCDR2 contains 21 bits and is used to perform reads and writes to any of the UCB1100’s or  
UCB1200’s registers. MCDR2 contains three separate fields: MCDR2<15:0> is the 16-bit register  
data field, MCDR2<16> is a 1-bit read/write control bit, and MCDR2<20:17> is the 4-bit register  
address field. A value written to MCDR2 is placed in the correct position within the 64-bit  
subframe 0, is transmitted to the off-chip codec, and is used to perform a read or write operation to  
the addressed codec register. Note that the contents of the addressed register are always returned in  
the receive data frame and placed in the MCDR2 regardless of the state of the read/write bit. Thus  
for write cycles, both a write and a read occurs, and for read cycles, only a read occurs. When  
MCDR2 is read, the value returned from the last read or write operation, which was completed to  
the codec, is returned.  
A register write is performed by writing the correct value to each of the three fields within MCDR2  
using one 16- or 32-bit write, ensuring that the read/write bit is set. Its contents are then transferred  
to the correct fields within the serial shifter on the next rising edge of the SFRM signal, and then to  
the codec via the TXD4 pin during subframe 0. The value within MCDR2<15:0> is written to the  
selected codec register at the end of subframe 0 (during the 65th bit of the frame). The data written  
to the control register and its address is returned to the MCP during the next data frame, and is  
placed back within MCDR2 with the read/write bit reset to zero. For a write operation, since the  
addressed register is written at the end of subframe 0, the data returned during the frame in which  
the write occurred represents the previous contents of the register. The updated value is returned  
during the next data frame.  
A register read is performed by writing the address of the register to read while clearing the  
read/write bit to zero within MCDR2. Again, the data is transferred to the serial shifter on the next  
rising edge of the SFRM signal and is transmitted to the UCB1100 or UCB1200 during subframe 0.  
Because the address and read/write control bit fields are placed near the beginning of the serial  
stream output, the codec performs the read immediately after the read/write bit is received (during  
the 41st bit of the frame), and the value contained within the addressed register is sent back to the  
MCP in the same data frame, and is placed within MCDR2.  
Once MCDR2 is written with a value to execute a read or write, the operation is performed every  
MCP data frame until a new value is written to the register. Thus continual reads or writes are made  
to the addressed codec register until a new read or write operation is configured.  
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Peripheral Control Module  
The following table shows the location of MCP data register 2. Note that the reset state of all  
MCDR2 bits is unknown (indicated by question marks), writes to reserved bits are ignored, and  
reads return zeros.  
.
Address: 0h 8006 0010  
MCP Data Register 2: MCDR2  
Read/Write  
Bit  
Reset  
Bit  
31  
30  
29  
28  
0
27  
0
26  
Reserved  
0
25  
24  
23  
22  
21  
0
20  
19  
18  
17  
16  
Reg Address R/W  
0
?
0
0
0
0
0
0
0
?
4
?
?
2
?
?
1
?
15  
?
14  
?
13  
?
12  
11  
10  
9
8
7
6
5
3
0
?
Data Value Returned by a Codec Register Read or Write  
Reset  
?
?
?
?
?
?
?
?
?
?
Read Access  
Bit  
31  
30  
29  
28  
27  
26  
Reserved  
0
25  
24  
23  
22  
21  
20  
19  
18  
17  
16  
R/  
W
Reg Address R/W  
Reset  
Bit  
0
15  
?
0
14  
?
0
13  
?
0
0
0
9
0
8
0
7
0
6
0
5
?
?
?
2
?
?
1
?
?
0
?
12  
11  
10  
4
3
Data Value to be Written to the Addressed Codec Register  
Reset  
?
?
?
?
?
?
?
?
?
?
Write Access  
Bit  
Name  
Codec  
Description  
15..0  
Codec register read/write data.  
Register  
Read/  
Write  
Read – If a codec write was last performed, contains data of previous register access;  
next frame contains the data that was written. If a codec read was last performed,  
contains data from the read register.  
Data  
Write – Used to specify what data to write to the addressed register, ignored for a codec  
register read.  
16  
R/W  
Read/write.  
Read – Returns a zero.  
Write – Used to control whether the addressed register is read or written (write = 1,  
read = 0).  
20..17  
Codec  
Register  
Read/  
Write  
Address  
Codec register read/write address.  
Read – If a codec write was last performed, contains address of previous register  
access; next frame contains the address of the write. If a codec read was last  
performed, contains address of the register read.  
Write – Used to address a register to perform a read or write.  
Reserved.  
31.. 21  
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Peripheral Control Module  
11.12.6 MCP Status Register  
The MCP status register (MCSR) contains bits that signal FIFO overrun and underrun errors, and  
FIFO service requests. Each of these conditions signal an interrupt request to the interrupt  
controller. The status register also flags when transmit FIFOs are not full, when the receive FIFOs  
are not empty, when a codec control register read or write is complete, and when the audio or  
telecom portion of the codec is enabled (no interrupt generated).  
A bit that can cause an interrupt signals the interrupt request as long as the bit is set. Once the bit is  
cleared, the interrupt is cleared. Read/write bits are called status bits; read-only bits are called flags.  
Status bits are referred to as “sticky” (once set by hardware, must be cleared by software). Writing  
a one to a sticky status bit clears it; writing a zero has no effect. Read-only flags are set and cleared  
by hardware; writes have no effect. Additionally, some bits that cause interrupts have  
corresponding mask/enable bits in the control register and are indicated in the following section  
headings. Note that the user has the ability to mask all MCP interrupts by clearing bit 18 within the  
interrupt controller mask register (ICMR). See the Section 9.2, “Interrupt Controller” on  
11.12.6.1 Audio Transmit FIFO Service Request Flag (ATS) (read-only,  
maskable interrupt)  
The audio transmit FIFO service request flag (ATS) is a read-only bit that is set when the audio  
transmit FIFO is nearly empty and requires service to prevent an underrun. ATS is set any time the  
audio transmit FIFO has four or fewer entries of valid data (half-full or less), and is cleared when it  
has five or more entries of valid data. When the ATS bit is set, an interrupt request is made unless  
the audio transmit FIFO interrupt request mask (ATE) bit is cleared. The state of ATS is also sent to  
the DMA controller, and can be used to signal a DMA service request. Note that ATE has no effect  
on the generation of the DMA service request. After the DMA or CPU fills the FIFO such that four  
or more locations are filled within the audio transmit FIFO, the ATS flag (and the service request  
and/or interrupt) is automatically cleared.  
11.12.6.2 Audio Receive FIFO Service Request Flag (ARS) (read-only, maskable  
interrupt)  
The audio receive FIFO service request flag (ARS) is a read-only bit that is set when the audio  
receive FIFO is nearly filled and requires service to prevent an overrun. ARS is set whenever the  
audio receive FIFO has four or more entries of valid data (half-full or more), and is cleared when it  
has three or fewer (less than half-full) entries of data. When the ARS bit is set, an interrupt request  
is made unless the audio receive FIFO interrupt request mask (ARE) bit is cleared. The state of  
ARS is also sent to the DMA controller, and can be used to signal a DMA service request. Note that  
ARE has no effect on the generation of the DMA service request. After the DMA or CPU fills the  
FIFO such that four or more locations are filled within the receive FIFO, the ARS flag (and the  
service request and/or interrupt) is automatically cleared.  
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Peripheral Control Module  
11.12.6.3 Telecom Transmit FIFO Service Request Flag (TTS) (read-only,  
maskable interrupt)  
The telecom transmit FIFO service request flag (TTS) is a read-only bit that is set when the  
telecom transmit FIFO is nearly empty and requires service to prevent an underrun. TTS is set  
whenever the telecom transmit FIFO has four or fewer entries of valid data (half-full or less), and is  
cleared when it has five or more entries of valid data. When the TTS bit is set, an interrupt request  
is made unless the telecom transmit FIFO interrupt request mask (TTE) bit is cleared. The state of  
TTS is also sent to the DMA controller, and can be used to signal a DMA service request. Note that  
TTE has no effect on the generation of the DMA service request. After the DMA or CPU fills the  
FIFO such that four or more locations are filled within the telecom transmit FIFO, the TTS flag  
(and the service request and/or interrupt) is automatically cleared.  
11.12.6.4 Telecom Receive FIFO Service Request Flag (TRS) (read-only,  
maskable interrupt)  
The telecom receive FIFO service request flag (TRS) is a read-only bit that is set when the telecom  
receive FIFO is nearly filled and requires service to prevent an overrun. TRS is set whenever the  
telecom receive FIFO has four or more entries of valid data (half-full or more), and is cleared when  
it has three or fewer (less than half-full) entries of data. When the TRS bit is set, an interrupt  
request is made unless the telecom receive FIFO interrupt request mask (TRE) bit is cleared. The  
state of TRS is also sent to the DMA controller, and can be used to signal a DMA service request.  
Note that TRE has no effect on the generation of the DMA service request. After the DMA or CPU  
fills the FIFO such that four or more locations are filled within the receive FIFO, the TRS flag (and  
the service request and/or interrupt) is automatically cleared.  
11.12.6.5 Audio Transmit FIFO Underrun Status (ATU) (read/write,  
nonmaskable interrupt)  
The audio transmit FIFO underrun status bit (ATU) is set when the audio transmit logic attempts to  
fetch data from the FIFO after it has been completely emptied. When an underrun occurs, the audio  
transmit logic continuously transmits the last valid audio value, which was transmitted before the  
underrun occurred. Once data is placed in the FIFO and it is transferred down to the bottom, the  
audio transmit logic uses the new value within the FIFO for transmission. When the ATU bit is set,  
an interrupt request is made.  
11.12.6.6 Audio Receive FIFO Overrun Status (ARO) (read/write, nonmaskable  
interrupt)  
The audio receive FIFO overrun status bit (ARO) is set when the audio receive logic attempts to  
place data into the audio receive FIFO after it has been completely filled. Each time a new piece of  
data is received, the set signal to the ARO status bit is asserted, and the newly received data is  
discarded. This process is repeated for each new piece of data received until at least one empty  
FIFO entry exists. When the ARO bit is set, an interrupt request is made.  
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Peripheral Control Module  
11.12.6.7 Telecom Transmit FIFO Underrun Status (TTU) (read/write,  
nonmaskable interrupt)  
The telecom transmit FIFO underrun status bit (TTU) is set when the telecom transmit logic  
attempts to fetch data from the FIFO after it has been completely emptied. When an underrun  
occurs, the telecom transmit logic continuously transmits the last valid telecom value, which was  
transmitted before the underrun occurred. Once data is placed in the FIFO and it is transferred  
down to the bottom, the telecom transmit logic uses the new value within the FIFO for  
transmission. When the TTU bit is set, an interrupt request is made.  
11.12.6.8 Telecom Receive FIFO Overrun Status (TRO) (read/write,  
nonmaskable interrupt)  
The telecom receive FIFO overrun status bit (TRO) is set when the telecom receive logic places  
data into the telecom receive FIFO after it has been completely filled. Each time a new piece of  
data is received, the set signal to the TRO status bit is asserted, and the newly received data is  
discarded. This process is repeated for each new piece of data received until at least one empty  
FIFO entry exists. When the TRO bit is set, an interrupt request is made.  
11.12.6.9 Audio Transmit FIFO Not Full Flag (ANF) (read-only, noninterruptible)  
The audio transmit FIFO not full flag (ANF) is a read-only bit that is set whenever the audio  
transmit FIFO contains one or more entries that do not contain valid data and is cleared when the  
FIFO is completely full. This bit can be polled when using programmed I/O to fill the audio  
transmit FIFO over its halfway mark. This bit does not request an interrupt.  
11.12.6.10 Audio Receive FIFO Not Empty Flag (ANE) (read-only,  
noninterruptible)  
The audio receive FIFO not empty flag (ANE) is a read-only bit that is set whenever the audio  
receive FIFO contains one or more entries of valid data and is cleared when it no longer contains  
any valid data. This bit can be polled when using programmed I/O to remove remaining bytes of  
data from the receive FIFO because DMA service and CPU interrupt requests are made only when  
four or more bytes reside within the FIFO (3, 2, or 1 bytes may remain at the end of a frame). This  
bit does not request an interrupt.  
11.12.6.11 Telecom Transmit FIFO Not Full Flag (TNF) (read-only,  
noninterruptible)  
The telecom transmit FIFO not full flag (TNF) is a read-only bit that is set whenever the telecom  
transmit FIFO contains one or more entries that do not contain valid data and is cleared when the  
FIFO is completely full. This bit can be polled when using programmed I/O to fill the telecom  
transmit FIFO over its halfway mark. This bit does not request an interrupt.  
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Peripheral Control Module  
11.12.6.12 Telecom Receive FIFO Not Empty Flag (TNE) (read-only,  
noninterruptible)  
The telecom receive FIFO not empty flag (TNE) is a read-only bit that is set whenever the telecom  
receive FIFO contains one or more entries of valid data and is cleared when it no longer contains  
any valid data. This bit can be polled when using programmed I/O to remove remaining bytes of  
data from the receive FIFO because DMA service and CPU interrupt requests are made only when  
four or more bytes reside within the FIFO (3, 2, or 1 bytes may remain at the end of a frame). This  
bit does not request an interrupt.  
11.12.6.13 Codec Write Completed Flag (CWC) (read-only, noninterruptible)  
The codec write completed (CWC) flag is set after the following sequence occurs: a register write  
command is issued to the codec by writing to MCDR2; the write command is sent to the codec via  
subframe 0; the data value is latched within the addressed codec register at the beginning of  
subframe 1 (the 65th bit of the frame); the address and value that was written is returned to the  
MCP via the next subframe 0; and the returned values are latched in MCDR2. CWC is  
automatically cleared when MCDR2 is read or written. This bit does not request an interrupt.  
11.12.6.14 Codec Read Completed Flag (CRC) (read-only, noninterruptible)  
The codec read completed (CRC) flag is set after the following sequence occurs: a register read  
command is issued to the codec by writing to MCDR2; the read command is sent to the codec via  
subframe 0; the data value contained within the addressed codec register is loaded into the codec’s  
serial shift register during subframe 0 (the 41st bit of the frame); the address and value that was  
read is returned to the MCP via the same subframe 0; and the returned values are latched in  
MCDR2. CRC is automatically cleared when MCDR2 is read or written. This bit does not request  
an interrupt.  
11.12.6.15 Audio Codec Enabled Flag (ACE) (read-only, noninterruptible)  
The audio codec enabled (ACE) flag indicates when the audio codec input and/or output is enabled,  
which in turn, indicates that the audio sample rate counter is enabled. This flag is set after the  
following sequence occurs: a register write command is issued to Audio Control Register B  
(register 8), and either bit 14 or 15 is set (aud_in_ena or aud_out_ena) by writing to MCDR2; the  
write command is sent to the codec via subframe 0; the data value is latched within codec register  
8; and SFRM is asserted to indicate the start of the next frame. ACE is automatically cleared using  
the same sequence with the exception that bits 14 and 15 are cleared, disabling both the input and  
output paths of the audio codec. This bit does not request an interrupt.  
11.12.6.16 Telecom Codec Enabled Flag (TCE) (read-only, noninterruptible)  
The telecom codec enabled (TCE) flag indicates when the telecom codec input and/or output is  
enabled, which in turn, indicates that the telecom sample rate counter is enabled. This flag is set  
after the following sequence occurs: a register write command is issued to Telecom Control  
Register B (register 6), and either bit 14 or 15 is set (tel_in_ena or tel_out_ena) by writing to  
MCDR2; the write command is sent to the codec via subframe 0; the data value is latched within  
codec register 6; and SFRM is asserted to indicate the start of the next frame. TCE is automatically  
cleared using the same sequence with the exception that bits 14 and 15 are cleared, disabling both  
the input and output paths of the telecom codec. This bit does not request an interrupt.  
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Peripheral Control Module  
The following table shows the bit locations corresponding to the status and flag bits within the  
MCP status register. MCSR contains a collection of read/write, read-only, interruptible, and  
noninterruptible bits (refer to the bit descriptions above). Writes to read-only bits have no effect.  
The user must clear set status bits before enabling the MCP. Note that writes to reserved bits are  
ignored and reads return zeros; question marks indicate that the values are unknown at reset.  
Read/Write &  
Address: 0h 8006 0018  
MCP Status Register: MCSR  
Read-Only  
Bit  
Reset  
Bit  
31  
30  
29  
0
28  
0
27  
0
26  
0
25  
24  
23  
22  
0
21  
0
20  
0
19  
0
18  
0
17  
16  
0
Reserved  
0
0
0
0
0
0
15  
TCE  
0
14  
ACE  
0
13  
CRC  
0
12  
CWC  
0
11  
TNE  
0
10  
TNF  
1
9
ANE  
0
8
ANF  
1
7
TRO  
?
6
TTU  
?
5
ARO  
?
4
ATU  
?
3
TRS  
0
2
TTS  
0
1
ARS  
0
0
ATS  
0
Reset  
Bit  
Name  
Description  
Audio transmit FIFO service request flag (read-only).  
0
ATS  
ARS  
TTS  
TRS  
0 – Audio transmit FIFO is more than half-full (five or more entries filled) or MCP  
disabled.  
1 – Audio transmit FIFO is half-full or less (four or fewer entries filled) and MCP  
operation is enabled, DMA service request signalled, interrupt request signalled if not  
masked (if ATE=1).  
1
2
3
Audio receive FIFO service request (read-only).  
0 – Audio receive FIFO is less than half-full (three or fewer entries filled) or MCP  
disabled.  
1 – Audio receive FIFO is half-full or more (four or more entries filled) and MCP  
operation is enabled, DMA service request signalled, interrupt request signalled if not  
masked (if ARE=1).  
Telecom transmit FIFO service request flag (read-only).  
0 – Telecom transmit FIFO is more than half-full (five or more entries filled) or MCP  
disabled.  
1 – Telecom transmit FIFO is half-full or less (four or fewer entries filled) and MCP  
operation is enabled, DMA service request signalled, interrupt request signalled if not  
masked (if TTE=1).  
Telecom receive FIFO service request (read-only).  
0 – Telecom receive FIFO is less than half full (three or fewer entries filled) or MCP  
disabled.  
1 – Telecom receive FIFO is half full or more (four or more entries filled) and MCP  
operation is enabled, DMA service request signalled, interrupt request signalled if not  
masked (if TRE=1).  
4
5
ATU  
Audio transmit FIFO underrun.  
0 – Audio transmit FIFO has not experienced an underrun.  
1 – Audio transmit logic attempted to fetch data from transmit FIFO while it was empty  
request interrupt.  
ARO  
Audio receive FIFO overrun.  
0 – Audio receive FIFO has not experienced an overrun.  
1 – Audio receive logic attempted to place data into receive FIFO while it was full,  
request  
interrupt.  
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Peripheral Control Module  
Bit  
Name  
Description  
6
TTU  
Telecom transmit FIFO underrun.  
0 – Telecom transmit FIFO has not experienced an underrun.  
1 – Telecom transmit logic attempted to fetch data from transmit FIFO while it was  
empty, request interrupt.  
7
TRO  
Telecom receive FIFO overrun.  
0 – Telecom receive FIFO has not experienced an overrun.  
1 – Telecom receive logic attempted to place data into receive FIFO while it was full,  
request interrupt.  
8
ANF  
ANE  
TNF  
TNE  
CWC  
CRC  
Audio transmit FIFO not full (read-only).  
0 – Audio transmit FIFO is full.  
1– Audio transmit FIFO is not full.  
9
Audio receive FIFO not empty (read-only).  
0 – Audio receive FIFO is empty.  
1 – Audio receive FIFO is not empty.  
10  
11  
12  
13  
Telecom transmit FIFO not full (read-only).  
0 – Telecom transmit FIFO is full.  
1 – Telecom transmit FIFO is not full.  
Telecom receive FIFO not empty (read-only).  
0 – Telecom receive FIFO is empty.  
1 – Telecom receive FIFO is not empty.  
Codec write completed (read-only).  
0 – A write to a codec register has not completed since the last time this bit was cleared.  
1 – A write to a codec register has been transmitted and has updated the register.  
Codec read completed (read-only).  
0 – The value read from the addressed codec register has not been returned to  
MCDR2.  
1 – The value read from the addressed codec register is now in MCDR2.  
Audio codec enabled (read-only).  
14  
15  
ACE  
TCE  
0 – The audio codec input and output is disabled (bits 14 and 15 are 0 in Audio Control  
Reg B).  
1 – Audio codec input and/or output is enabled (bits 14 and/or 15 is 1 in Audio Control  
Reg B).  
Telecom codec enabled.  
0 – The telecom codec input and output is disabled (bits 14 and 15 are 0 in Telecom  
Cntl Reg B).  
1 – Telecom codec input and/or output is enabled (bits 14 and/or 15 is 1 in Telecom Cntl  
Reg B).  
31..16  
Reserved.  
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Peripheral Control Module  
11.12.7 SSP Operation  
Following reset, both the MCP and SSP logic within serial port 4 is disabled and control of its pins is  
given to the PPC that configures all four pins as inputs. To enable SSP operation, the programmer  
should first clear any interruptible status bits, which are set following the reset by writing a one to  
them. Next, the user should program the SSP’s control registers with the desired mode of operation,  
ensuring that the register containing the SSP enable bit is programmed last. Note that the MCP has  
precedence over the SSP and must be disabled first before enabling the SSP. The user can choose to  
either “prime” the transmit FIFO by writing up to eight 16-bit values, or allow the transmit FIFO  
service request to interrupt the CPU or trigger a DMA transfer to fill the FIFO. Once enabled,  
transmission/reception of data begins on the transmit (TXD4) and receive (RXD4) pins, and is  
synchronously controlled by the serial clock (SCLK) and serial frame (SFRM) pins.  
11.12.7.1 Frame Format  
Each data frame is between 4 and 16 bits long depending on the size of data programmed, and is  
transmitted starting with the MSB. There are three basic frame types that can be selected: Motorola*  
SPI, Texas Instruments* synchronous serial, and National Microwire*. For all three formats, the  
serial clock (SCLK) is held low or inactive, while the SSP is idle and transitions at the programmed  
frequency only during active transmission of data. For Motorola* SPI and National Microwire*  
frame formats, the serial frame (SFRM) pin is active low, and is asserted (pulled down) during the  
entire frame’s transmission. In these modes, the SFRM pin is used to select the off-chip slave serial  
device, enabling it for transmission. For Texas Instruments* format, the SFRM pin is pulsed for one  
serial clock period starting at its rising edge, prior to each frame’s transmission. The type of serial  
clock edges used to drive and sample data are different for all three modes. For National Microwire*  
format, both the SSP and the off-chip slave device drive their output data on the falling edge of  
SCLK, and latch data from the other device on the rising edge. For Texas Instruments* format, both  
the SSP and the off-chip slave device drive their output data on the rising edge of SCLK, and latch  
data from the other device on the falling edge. For Motorola* SPI format, the user has the option of  
which edge of SCLK to drive and sample data, as well as the phase of the SCLK signal (whether it is  
shifted one-half period to the left or right during the frame transmission).  
Unlike the full-duplex transmission of the other two frame formats, the National Microwire*  
format uses a special master-slave messaging technique that operates at half-duplex. In this mode,  
when a frame begins, an 8-bit control message is transmitted to the off-chip slave. During this  
transmit, no incoming data is received by the SSP. After the message has been sent, the off-chip  
slave decodes it and responds with the requested data after waiting one serial clock after the last bit  
of the 8-bit control message has been sent. The returned data can be 4 to 16 bits in length, making  
the total frame length anywhere from 13 to 25 bits.  
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Peripheral Control Module  
Figure 11-35 shows the Texas Instruments* synchronous serial frame format for a single  
transmitted frame and when back-to-back frames are transmitted. In this mode, SCLK and SFRM  
are forced low, and the transmit data line SA-1100. Once the bottom entry of the transmit FIFO  
contains data, SFRM is pulsed high for one SCLK period and the value to be transmitted is  
transferred from the transmit FIFO to the transmit logic’s serial shift register. On the next rising  
edge of SCLK, the MSB of the 4- to 16-bit data frame is shifted to the TXD4 pin. Likewise, the  
MSB of the received data is shifted onto the RXD4 pin by the off-chip serial slave device. Both the  
SSP and the off-chip serial slave device then latch each data bit into their serial shifter on the  
falling edge of each SCLK. The received data is transferred from the serial shifter to the receive  
FIFO on the first rising edge of SCLK after the LSB has been latched. Note that the transmit pin  
retains the last value it transmits (the value of bit <0>, when the frame completes and the SSP  
enters idle mode). If the SSP is disabled or a reset occurs, the transmit pin is reset to zero.  
Figure 11-35. Texas Instruments* Synchronous Serial Frame Format  
.
SCLK  
...  
SFRM  
...  
TXD4  
RXD4  
Bit<N>  
Bit<N..1>  
Bit<N..1>  
...  
Bit<1>  
Bit<1>  
Bit<0>  
Bit<N>  
MSB  
...  
Bit<0>  
LSB  
4 to 16 Bits  
Single Transfer  
SCLK  
SFRM  
TX/RX  
...  
...  
...  
...  
...  
Bit<0>  
Bit<N>  
Bit<N..1>  
...  
Bit<1>  
Bit<0>  
Bit<N>  
Bit<N..1>  
Bit<1>  
Bit<0>  
Continuous Transfers  
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Peripheral Control Module  
Figure 11-36 shows one of the four possible configurations for the Motorola* SPI frame format for  
a single transmitted frame and when back-to-back frames are transmitted. In this mode, SCLK and  
the transmit data line (TXD4) are forced low and SFRM is forced high, whenever the SSP is  
disabled or the SA-1100 is reset. Once the bottom entry of the transmit FIFO contains data, SFRM  
is pulled low and remains low for the duration of the frame’s transmission. The falling edge of  
SFRM causes the value for transmission to be transferred from the bottom transmit FIFO entry to  
the transmit logic’s serial shift register, and the MSB of the 4- to 16-bit data frame is shifted onto  
the TXD4 pin a half an SCLK period later (note that the SCLK pin does not transition at this point).  
The MSB of the received data is shifted onto the RXD4 pin by the off-chip serial slave device as  
soon as the serial framing signal goes low. Both the SSP and the off-chip serial slave device then  
latch each data bit into their serial shifter on the rising edge of each SCLK. At the end of the frame,  
the SFRM pin is pulled high one SCLK period after the last bit has been latched in the receive  
serial shifter, which causes the data to be transferred to the receive FIFO. Note that the off-chip  
slave device can tristate the receive line either on the falling edge of SCLK after the LSB has been  
latched by the receive shifter or when the SFRM pin goes high. Also note that the transmit pin  
retains the last value it transmits (the value of bit <0>, when the frame completes and the SSP  
enters idle mode). If the SSP is disabled or a reset occurs, the transmit pin is reset to zero. All four  
frame programming options are described in the SSP Control Register 1 section.  
For continuous transfers, data transmission begins and ends in the same manner as a single transfer;  
however, the SFRM line is continuously asserted (held low) and transmission of data occurs  
back-to-back (the MSB of the next frame follows directly after the LSB of the previous frame). In  
this example, each of the received data values is transferred from the receive shifter to the receive  
FIFO on the falling edge SCLK after the LSB of the frame has been latched into the SSP.  
Figure 11-36. Motorola* SPI Frame Format  
SCLK  
...  
SFRM  
...  
TXD4  
RXD4  
Bit<N>  
Bit<N..1>  
Bit<N..1>  
...  
Bit<1>  
Bit<1>  
Bit<0>  
Bit<N>  
...  
Bit<0>  
LSB  
MSB  
4 to 16 Bits  
Single Transfer  
SCLK  
SFRM  
TX/RX  
...  
...  
...  
...  
...  
Bit<0>  
Bit<N>  
Bit<N..1>  
...  
Bit<1>  
Bit<0>  
Bit<N>  
Bit<N..1>  
Bit<1>  
Bit<0>  
Continuous Transfers  
Note: The phase and polarity of SCLK can be configured for four different modes. This example shows just one of those modes.  
See the Section 11.12.10, “SSP Control Register 1” on page 11-177 for a complete description of each mode.  
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Peripheral Control Module  
Figure 11-37 shows the National Microwire* frame format for a single transmitted frame and when  
back-to-back frames are transmitted. Microwire format is very similar to SPI format, except that  
transmission is half- instead of full-duplex, using a master-slave message passing technique. Each  
serial transmission begins with an 8-bit control word that is transmitted from the SSP to the  
off-chip slave device. During this transmit, no incoming data is received by the SSP. After the  
message has been sent, the off-chip slave decodes it and responds with the requested data after  
waiting one serial clock after the last bit of the 8-bit control message has been sent. The returned  
data is 4 to 16 bits in length, making the total frame length anywhere from 13 to 25 bits.  
SCLK and the transmit data line (TXD4) is forced low, and SFRM is forced high whenever the SSP  
is disabled or following a reset of the SA-1100. Once enabled, transmission is triggered by writing  
a control byte to the transmit FIFO. The falling edge of SFRM causes the value contained within  
the bottom entry of the transmit FIFO to be transferred to the transmit logic’s serial shift register  
and the MSB of the 8-bit control frame to be shifted onto the TXD4 pin. SFRM remains low for the  
duration of the frame’s transmission. The RXD4 pin remains tristated during this transmission. The  
off-chip serial slave device latches each control bit into its serial shifter on the rising edge of each  
SCLK. After the last bit is latched by the slave device, the control byte is decoded during a  
one-clock waitstate, and the slave responds by transmitting data back to the SSP, driving each bit  
onto the RXD4 line on the falling edge of SCLK. The SSP, in turn, latches each bit on the rising  
edge of SCLK. At the end of the frame, for single transfers, the SFRM signal is pulled high one  
SCLK period after the last bit has been latched in the receive serial shifter, which causes the data to  
be transferred to the receive FIFO. Note that the off-chip slave device can tristate the receive line  
either on the falling edge of SCLK after the LSB has been latched by the receive shifter or when  
the SFRM pin goes high. Also note that the transmit pin retains the last value it transmits (the value  
of bit <0>, when the frame completes and the SSP enters idle mode). If the SSP is disabled or a rest  
occurs, the transmit pin is reset to zero.  
For continuous transfers, data transmission begins and ends in the same manner as a single transfer;  
however, the SFRM line is continuously asserted (held low) and transmission of data occurs  
back-to-back (the control byte of the next frame follows directly after the LSB of the received data  
from the previous frame). Each of the received data values is transferred from the receive shifter on  
the falling edge SCLK after the LSB of the frame has been latched into the SSP.  
Figure 11-37. National Microwire* Frame Format  
SCLK  
SFRM  
...  
...  
...  
...  
...  
TXD4  
RXD4  
Bit<7>  
...  
8-Bit Control  
...  
Bit<0>  
1 Clk  
Bit<N>  
...  
Bit<0>  
4 to 16 Bits  
Single Transfer  
SCLK  
SFRM  
...  
...  
...  
...  
...  
...  
...  
...  
...  
TXD4  
RXD4  
Bit<0>  
Bit<7>  
Bit<0>  
1 Clk  
1 Clk  
Bit<N>  
...  
Bit<0>  
Continuous Transfers  
...  
Bit<N>  
...  
Bi  
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Peripheral Control Module  
11.12.7.2 Baud Rate Generation  
The baud or bit rate is derived by dividing down the 3.6864-MHz clock generated by the on-chip  
PLL. The clock is first divided by a fixed value of 2 and then by a programmable number between  
1 and 256. This programmability provides a range of transmission rates ranging from 7.2 Kbps to  
1.8432 Mbps. The resultant clock is used to drive the SCLK pin and by the transmit and receive  
logic’s serial shifters to drive and latch data, respectively.  
11.12.7.3  
SSP Transmit and Receive FIFOs  
To reduce chip size as well as power consumption, the SSP’s FIFOs use self-timed logic (they are  
not clocked). Because of process and environmental variations, the depth at which a service request  
is triggered to empty the receive FIFO is variable. This variation spans a maximum of four FIFO  
entries, thus the receive FIFO service request can be made at four different FIFO depths. To  
compensate for this variability and guarantee that at least four valid entries of data exist within the  
FIFO before generating a service request, an extra four entries have been added to the receive FIFO  
(four entries more than the transmit FIFO). Thus the transmit FIFO is 8 entries deep and the receive  
FIFO is 12 entries deep. The point at which the receive FIFO service request is triggered spans  
one-third (four entries) of the 12-entry FIFO. The service request is signalled at a depth from  
one-third full to two-thirds full (when the FIFO contains five, six, seven, or eight entries of data).  
This service request variation only applies to an empty FIFO that is filled (receive FIFO). It does  
not apply to a full FIFO that is emptied (transmit FIFO). Thus the transmit FIFO is guaranteed to  
signal a service request when it has four or more empty entries and negate the request when the  
FIFO contains five or more entries that are filled.  
If the DMA is used to service either one or both of the SSP’s FIFOs, the burst size must be set to  
four half-words, even though more than four entries of data may exist within the receive FIFO. If  
programmed I/O is used to service the FIFOs, a maximum of four words may be added to the  
transmit FIFO without checking if more space is available. Likewise, a maximum of four words  
may be removed from the receive FIFO without checking if more data is available. After this point,  
the user must poll a set of status bits, which indicates if any data remains in the receive FIFO or if  
space is available in the transmit FIFO, before emptying or filling the FIFOs any further.  
The width of each entry within the FIFOs is 16 bits. However, the SSP supports data sizes of 4  
through 16 bits. Any data that is less than 16-bits wide must be left-justified when writing or  
DMAing data to the transmit FIFO. Likewise, data received by the SSP is left-justified when it is  
placed within the receive FIFO. Figure 11-38 shows the required data alignment for the transmit  
and receive FIFOs. The user must left-justify data to be transmitted, and shift received data to the  
right before using the results.  
Figure 11-38. Transmit/Receive FIFO Data Format  
Bit  
15  
14  
13  
12  
11  
0
10  
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4-Bit Data  
5-Bit Data  
0
0
0
0
0
0
0
0
0
0
0
0
..  
15-Bit Data  
16-bit Data  
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Peripheral Control Module  
11.12.7.4 CPU and DMA Register Access Sizes  
Bit positioning, byte ordering, and addressing of the SSP are described in terms of little endian  
ordering. All SSP registers are 16-bits wide and are located in the least significant half-word of  
individual words. The ARM peripheral bus does not support byte or half-word operations. All  
reads and writes of the SSP by the CPU should be word wide. Two separate dedicated DMA  
requests exist for both the transmit and the receive FIFO. If the DMA controller is used to service  
the transmit and/or receive FIFOs, the user must ensure the DMA is properly configured to perform  
half-word wide accesses, using four half-words per burst (half the size of the FIFOs). Byte-wide  
DMA accesses for data widths of 4..8 bits are not permitted. For all data sizes 4..16 bits, the user  
must left-justify the data within each individual half-word in external memory for the DMA,  
starting with the most significant bit. Likewise, when using programmed I/O to service the SSP’s  
transmit FIFO, the user must also left-justify the data written or read to/from the data register. Note  
that a separate set of registers also exist to configure MCP operation. See the following sections for  
a full description of programming and operation of serial port 4 as an MCP, a summary of serial  
port 4’s MCP registers, and for a summary of its SSP registers.  
11.12.7.5 Alternate SSP Pin Assignment  
If the SSP and MCP both need to be used at the same time, general-purpose I/O pins 10 through 13  
(GPIO<10-13>) can be reassigned by programming the PPC pin assignment register (PPAR). This  
allows the MCP dedicated use of the four pins assigned to serial port 4, and the SSP dedicated use of  
the GPIO pins. When the SSP pin reassignment (SPR) bit is set in PPAR, the following pin  
assignments are made: GPIO<10> is used for transmit, GPIO<11> for receive, GPIO<12> for serial  
clock, and GPIO<13> for serial frame. Note that the user must also set bits 10 through 13 in the GPIO  
alternate function register (GAFR) as well as set bits 10, 12, and 13 and clear bit 11 in the GPIO pin  
direction register (GPDR). Once the reassignment is made, these pins are no longer usable by the  
GPIO unit. See the “General-Purpose I/O” on page 9-1 for a description of how to program the  
for a description of how to program the PPC unit.  
11.12.8 SSP Register Definitions  
There are four registers within the SSP: two control registers, one data register, and one status  
register. The control registers are used to program the baud rate, data length, and frame format, and  
to select whether the CPU or DMA is used to service the SSP, and to enable/disable operation. The  
data register is 16 bits and addresses both the transmit and receive buffers. A read accesses the  
receive buffer; a write accesses the transmit buffer. Note that these are two physically separate  
buffers to allow full-duplex transmission. The status register contains bits that signal an overrun  
error, a transmit buffer service request, and a receive buffer service request. Each of these status  
conditions signal an interrupt request to the interrupt controller. The status register also flags when  
the SSP is actively transmitting data, when the transmit FIFO is not full, and when the receive  
FIFO is not empty (no interrupt generated).  
11.12.9 SSP Control Register 0  
The SSP control register 0 (SSCR0) contains four different bit fields that control various functions  
within the SSP.  
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Peripheral Control Module  
11.12.9.1 Data Size Select (DSS)  
The 4-bit data size select (DSS) field is used to select the size of the data transmitted and received by  
the SSP. Data can be 4 to 16 bits in length. When data is programmed to be less than 16 bits, received  
data is automatically right justified and the upper bits in the receive FIFO are zero filled by the  
receive logic. Transmit data must be right justified by the user before being placed into the transmit  
FIFO; however, the upper unused bits are ignored by the SSP’s transmit logic. Although it is possible  
to program data sizes of 1, 2, and 3 bits, these sizes are reserved and produce unpredictable results in  
the SSP. When National Microwire* frame format is selected, this bit field selects the size of the  
received data. Note that the size of the transmitted data is always 8 bits in this mode.  
11.12.9.2 Frame Format (FRF)  
The 2-bit frame format (FRF) bit field is used to select which frame format to use: Motorola* SPI  
(FRF=00), Texas Instruments* synchronous serial (FRF=01), or National Microwire* (FRF=10).  
See the preceding sections for a complete description of each frame format. Note that FRF=11 is  
reserved and produces unpredictable results.  
11.12.9.3 Synchronous Serial Port Enable (SSE)  
The SSP enable (SSE) bit is used to enable and disable all SSP operation. When SSE=0, the SSP is  
disabled; when SSE=1, it is enabled. Since the MCP and SSP both share the same pins, only one  
can be enabled at a time. If the user enables both at the same time, the MCP has precedence and the  
SSP remains disabled. However, both can be enabled when the SSP pin reassignment (SPR) bit  
within the PPC unit is set, which assigns the SSP to GPIO pins.  
When the SSP is disabled, all of its clocks are powered down to minimize power consumption. If  
the MCP is also disabled, the TXD4, RXD4, SCLK, and SFRM pins can be used for  
page 11-184 for a description of how to program the PPC unit to reassign the SSP’s pins and use  
serial port 4’s pins as I/Os. Note that SSE is the only control bit within the SSP that is reset to a  
known state. It is cleared to zero to ensure the SSP is disabled following a reset of the SA-1100.  
When the SSE bit is cleared during active operation, the SSP is disabled immediately, causing the  
current frame, which is being transmitted, to be terminated and control of serial port 4’s pins to be  
given to the PPC unit. Clearing SSE resets the SSP’s FIFOs. However the SSP’s control and status  
registers are not reset. The user must ensure these registers are properly reconfigured before  
reenabling the SSP.  
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Peripheral Control Module  
11.12.9.4 Serial Clock Rate (SCR)  
The 8-bit serial clock rate (SCR) bit field is used to select the baud or bit rate of the SSP. A total of  
256 different bit rates can be selected, ranging from a minimum of 7.2 Kbps to a maximum of  
1.8432 Mbps. The serial clock generator uses the 3.6864-MHz clock produced by the on-chip PLL,  
divided by a fixed value of 2, and then the programmable SCR value to generate the serial clock  
(SCLK). The resultant clock rate is driven out on the SCLK pin and is also used by the SSP’s transmit  
logic to drive data out on the TXD4 pin, and latch data on the RXD4 pin. Depending on the frame  
format selected, each transmitted bit is either driven on the rising or falling edge of SCLK, and is  
sampled on the opposite clock edge. The resultant serial clock rate, given a specific SCR value or  
required SCR value given a desired bit rate, can be calculated using the following two respective  
equations, where SCR is the decimal equivalent of the binary value programmed within the bit field:  
6
6
3.6864×10  
3.6864×10  
SCR = ------------------------------ 1  
BitRate = -----------------------------------  
2
x
BitRate  
2
x
(
SCR
+ 1
)  
The following table shows the bit locations corresponding to the five different control bit fields  
within SSP control register 0. Note that the SSE bit is the only control bit that is reset to a known  
state to ensure the SSP is disabled following a reset of the SA-1100. The reset state of all other  
control bits is unknown (indicated by question marks) and must be initialized before enabling the  
SSP. Reads of bit 6, which is reserved, return zero; writes have no effect.  
Address: 0h 8007 0060  
SSP Control Register 0: SSCR0  
Read/Write  
Bit  
15  
14  
13  
12  
?
11  
?
10  
9
8
7
6
5
?
4
?
3
?
2
?
1
DSS  
?
0
?
SCR  
SSE Res.  
FRF  
Reset  
?
?
?
?
?
?
0
0
Bit  
Name  
DSS  
Description  
3..0  
Data size select.  
0000 – Reserved, undefined operation.  
0001 – Reserved, undefined operation.  
0010 – Reserved, undefined operation.  
0011 – 4-bit data.  
0100 – 5-bit data.  
0101 – 6-bit data.  
0110 – 7-bit data.  
0111 – 8-bit data.  
1000 – 9-bit data.  
1001 – 10-bit data.  
1010 – 11-bit data.  
1011 – 12-bit data.  
1100 – 13-bit data.  
1101 – 14-bit data.  
1110 – 15-bit data.  
1111 – 16-bit data.  
5..4  
FRF  
Frame Format.  
00 – Motorola SPI frame format.  
01 – Texas Instruments Synchronous serial frame format.  
10 – National Microwire frame format.  
11 – Reserved, undefined operation.  
Reserved.  
6
7
SSE  
Synchronous serial port enable.  
0 – SSP operation disabled, control of pins given to PPC if MCP is also disabled.  
1 – SSP operation enabled if MCP disabled or if the PPC SSP pin reassignment bit is set  
(reassigns GPIO<13..10> to the SSP).  
15..8  
SCR  
Serial clock rate.  
Value (from 0 to 255) used to generate the transmission rate of the SSP.  
6
Bit Rate = 3.6864x10 /(2x(SCR+1)), where SCR is a decimal value.  
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Peripheral Control Module  
11.12.10 SSP Control Register 1  
The SSP control register 1 (SSCR1) contains six different bit fields that control various functions  
within the SSP.  
11.12.10.1 Receive FIFO Interrupt Enable (RIE)  
The receive FIFO interrupt enable (RIE) bit is used to mask or enable the receive FIFO service  
request interrupt. When RIE=0, the interrupt is masked and the state of the receive FIFO service  
request (RFS) bit within the SSP status register is ignored by the interrupt controller. When RIE=1,  
the interrupt is enabled, and whenever RFS is set (one), an interrupt request is made to the interrupt  
controller. Note that programming RIE=0 does not affect the current state of RFS or the receive  
FIFO logic’s ability to set and clear RFS, it only blocks the generation of the interrupt request. Also  
note that RIE does not affect generation of the receive FIFO DMA request, which is asserted  
whenever RFS=1.  
11.12.10.2 Transmit FIFO Interrupt Enable (TIE)  
The transmit FIFO interrupt enable (TIE) bit is used to mask or enable the transmit FIFO service  
request interrupt. When TIE=0, the interrupt is masked and the state of the transmit FIFO service  
request (TFS) bit within the SSP status register is ignored by the interrupt controller. When TIE=1,  
the interrupt is enabled, and whenever TFS is set (one), an interrupt request is made to the interrupt  
controller. Note that programming TIE=0 does not affect the current state of TFS or the transmit  
FIFO logic’s ability to set and clear TFS; it only blocks the generation of the interrupt request. Also  
note that TIE does not affect generation of the transmit FIFO DMA request, which is asserted  
whenever TFS=1.  
11.12.10.3 Loopback Mode (LBM)  
The loopback mode (LBM) bit is used to enable and disable the ability of the SSP transmit and  
receive logic to communicate. When LBM=0, the SSP operates normally. The transmit and receive  
data paths are independent and communicate via their respective pins. When LBM=1, the output of  
the transmit serial shifter is directly connected to the input of the receive serial shifter internally  
and control of the TXD4, RXD4, SCLK, and SFRM pins are given to the peripheral pin control  
(PPC) unit.  
11.12.10.4 Serial Clock Polarity (SPO)  
The serial clock polarity (SPO) bit selects the polarity or active/inactive state of the serial clock  
(SCLK) pin when Motorola* SPI format is selected (FRF=00). When SPO=0, the inactive or idle  
state of SCLK is low. Thus when the SSP is not actively transmitting/receiving data, the SCLK pin  
is held low. When SPO=1, the inactive or idle state of SCLK is high. Thus when the SSP is not  
actively transmitting/receiving data, the SCLK pin is held high. The programming of SPO alone  
does not determine which SCLK edges are used to drive and latch data to or from the transmit and  
receive pins. The programming of SPO and the serial clock phase (SPH) bit determines this. Note  
that SPO is ignored in all other modes except Motorola* SPI format (FRF=00).  
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Peripheral Control Module  
11.12.10.5 Serial Clock Phase (SPH)  
The serial clock phase (SPH) bit selects the phase relationship of the serial clock (SCLK) signal  
with the serial frame (SFRM) signal when Motorola* SPI format is selected (FRF=00). When  
SPH=0, SCLK remains in its inactive state (as programmed by SPO) for one full SCLK period  
duration after SFRM is asserted (driven low). SCLK continues to transition during the entire frame  
and is driven to its inactive state one-half SCLK period duration before SFRM is negated (driven  
high). When SPH=1, SCLK remains in its inactive state (as programmed by SPO) for one-half  
SCLK period duration after SFRM is asserted (driven low). SCLK continues to transition during  
the entire frame and is driven to its inactive state one full SCLK period duration before SFRM is  
negated (driven high). Using SPH and SPO together determine when SCLK is active during the  
assertion of SFRM and which edge of SCLK is used to drive data to the transmit pin as well as  
latch data from the receive pin. When SPO and SPH are the same value (both 0 or both 1), transmit  
data is driven on the falling edge of SCLK and receive data is latched on the rising edge of SCLK.  
Alternatively, when SPO and SPH are of opposite value (one 0 and the other 1), transmit data is  
driven on the rising edge of SCLK and receive data is latched on the falling edge of SCLK. Note  
that SPH is ignored in all other modes, except Motorola* SPI format (FRF=00).  
Figure 11-39 shows the pin timing for all four programming combinations of SPO and SPH. Note  
that SPO inverts the polarity of the SCLK signal, and SPH determines the phase relationship  
between SCLK and SFRM, shifting the SCLK signal one-half phase to the left or right during the  
assertion of SFRM.  
Figure 11-39. Motorola* SPI Frame Formats for SPO and SPH Programming  
SCLK SPO=0  
SCLK SPO=1  
SFRM  
...  
...  
...  
Bit<N..> ...  
TXD4  
RXD4  
Bit<N>  
Bit<1>  
Bit<1>  
Bit<0>  
Bit<N>  
Bit<N..>  
...  
Bit<0>  
LSB  
MSB  
4 to 16 Bits  
SPH = 0  
SCLK SPO=0  
SCLK SPO=1  
SFRM  
...  
...  
...  
Bit<N>  
Bit<N..>  
Bit<1>  
Bit<0>  
TXD4  
RXD4  
...  
...  
Bit<N>  
MSB  
Bit<N..>  
Bit<1>  
Bit<0>  
LSB  
4 to 16 Bits  
SPH = 1  
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Peripheral Control Module  
11.12.10.6 External Clock Select (ECS)  
The external clock select (ECS) bit selects whether the on-chip 3.6864-MHz clock is used by the  
SSP or if an off-chip clock is supplied via GPIO pin 19. When ECS=0, the SSP uses the on-chip  
3.6864-MHz clock to produce a range of serial transmission rates ranging from 7.2 Kbps to a  
maximum of 1.8432 Mbps. When ECS=1, the SSP uses GPIO<19> to input a clock supplied from  
off-chip. The frequency of the off-chip clock can be any value up to 3.6864 MHz. This off-chip  
clock is useful when a serial transmission rate, which is not an even multiple of 3.6864 MHz, is  
required for synchronization with the target off-chip slave device. When using GPIO pin 19 for the  
input clock, the user must also set bit 19 of the GPIO alternate function register (GAFR), and clear  
bit 19 of the GPIO pin direction register (GPDR). See the System Control Module chapter.  
The following table shows the bit locations corresponding to the three different control bit fields  
within SSP control register 1. The reset state of all bits is unknown (indicated by question marks)  
and must be initialized before enabling the SSP. Note that writes to reserved bits are ignored and  
reads return zero.  
Address: 0h 8007 0064  
SSP Control Register 1: SSCR1  
Read/Write  
Bit  
15  
0
14  
0
13  
0
12  
0
11  
10  
9
0
8
0
7
0
6
0
5
4
3
2
1
0
RIE  
?
SP  
O
Reserved  
ECS SPH  
LBM TIE  
Reset  
0
0
?
?
?
?
?
Bit  
Name  
Description  
0
RIE  
Receive FIFO interrupt enable.  
0 – Receive FIFO one- to two-thirds full or more condition does not generate an interrupt  
(RFS bit ignored).  
1 – Receive FIFO one- to two-thirds full or more condition generates an interrupt (state  
of RFS sent to interrupt controller).  
1
2
TIE  
Transmit FIFO interrupt enable.  
0 – Transmit FIFO half-full or less condition does not generate an interrupt (TFS bit  
ignored).  
1 – Transmit FIFO half-full or less condition generates an interrupt (state of TFS sent to  
interrupt controller).  
LBM  
Loopback mode.  
0 – Normal serial port operation enabled.  
1 – Output of transmit serial shifter is connected to input of receive serial shifter  
internally and control of TXD4, RXD4, SCLK, and SFRM pins is given to the PPC unit.  
3
4
SPO  
SP  
Serial clock polarity.  
0 – The inactive or idle state of SCLK is low.  
1 – The inactive or idle state of SCLK is high.  
Serial clock phase.  
0 – SCLK is in its inactive state one full cycle at the start of the frame and one-half cycle  
at the end of the frame.  
1 – SCLK is in its inactive state one-half cycle at the start of the frame and one full cycle  
at the end of the frame.  
5
ECS  
External clock select.  
0 – on-chip clock used to product the SSP’s serial clock and control all timing.  
1 – Clock input using GPIO pin 19 to drive the serial clock and all timing when serial  
rates that are not a multiple of 3.6864 MHz are needed.  
Note that bit 19 within GFAR and GPDR must be correctly configured within the system  
control module.  
15..6  
Reserved.  
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11.12.11 SSP Data Register  
The SSP data register (SSDR) is 16 bits wide and corresponds to the top and bottom entries of the  
transmit and receive FIFOs, respectively. When SSDR is read, the bottom entry of receive FIFO is  
accessed. As data is removed by the SSP’s receive logic from the incoming data frame, it is placed  
into the top entry of the receive FIFO and is transferred down an entry at a time until it reaches the  
last empty location within the FIFO. Data is removed by reading SSDR, which accesses the bottom  
entry of the FIFO. After SSDR is read, the bottom entry is invalidated, and all remaining values  
within the FIFO automatically transfer down one location.  
When SSDR is written, the topmost entry of the transmit FIFO is accessed. After a write, data is  
automatically transferred down to the lowest location within the transmit FIFO, which does not  
already contain valid data. Data is removed from the bottom of the FIFO one value at a time by the  
transmit logic, is loaded into the transmit serial shifter, and then is serially shifted onto the TXD4  
pin at the programmed bit rate.  
When a data size of less than 16 bits is selected, the user should left justify data written to the  
transmit FIFO. The transmit logic ignores the upper unused bits. Received data less than 16 bits is  
automatically right justified in the receive buffer and unused bits are zero filled. When the SSP is  
programmed for National Microwire* frame format, the default size for transmit data is 8 bits (the  
most significant byte is ignored) and the receive data size is controlled by the programmer.  
The following table shows the location of the SSP data register. Note that both FIFOs are cleared  
when the SA-1100 is reset or by writing a zero to SSE (SSP disabled).  
Address: 0h 8007 006C  
SSP Data Register: SSDR  
Read/Write  
Bit  
15  
14  
13  
12  
0
11  
0
10  
9
8
7
6
5
0
4
0
3
0
2
1
0
Bottom of Receive FIFO  
Reset  
0
0
0
0
0
0
0
0
0
0
0
Read Access  
Bit  
15  
0
14  
0
13  
0
12  
0
11  
0
10  
0
9
8
7
6
5
0
4
0
3
0
2
0
1
0
0
0
Top of Transmit FIFO  
Reset  
0
0
0
0
Write Access  
Bit  
Name  
Data  
Description  
15..0  
Top/bottom of transmit/receive FIFO.  
Read – Bottom of receive FIFO.  
Write – Top of transmit FIFO.  
Note: User should left justify data when SSP programmed for a data size less than 16  
bits. Top unused bits are ignored by transmit logic. Receive logic automatically right  
justifies data and zero fills unused bits.  
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Peripheral Control Module  
11.12.12 SSP Status Register  
The SSP status register (SSSR) contains bits that signal overrun errors as well as the transmit and  
receive FIFO service requests. Each of these hardware-detected events signals an interrupt request  
to the interrupt controller. The status register also contains flags that indicate when the SSP is  
actively transmitting characters, when the transmit FIFO is not full, and when the receive FIFO is  
not empty (no interrupt generated).  
A bit that can cause an interrupt signals the interrupt request as long as the bit is set. Once the bit is  
cleared, the interrupt is cleared. Read/write bits are called status bits; read-only bits are called flags.  
Status bits are referred to as “sticky” (once set by hardware, must be cleared by software). Writing  
a one to a sticky status bit clears it; writing a zero has no effect. Read-only flags are set and cleared  
by hardware; writes have no effect. Additionally, some bits that cause interrupts have  
corresponding mask/enable bits in the control registers and are indicated in the following section  
headings. Note that the user has the ability to mask all SSP interrupts by clearing bit 19 within the  
interrupt controller mask register (ICMR). See the Section 9.2, “Interrupt Controller” on page 9-11.  
11.12.12.1 Transmit FIFO Not Full Flag (TNF) (read-only, noninterruptible)  
The transmit FIFO not full flag (TNF) is a read-only bit that is set whenever the transmit FIFO  
contains one or more entries that do not contain valid data and is cleared when the FIFO is  
completely full. This bit can be polled when using programmed I/O to fill the transmit FIFO over  
its halfway mark. This bit does not request an interrupt.  
11.12.12.2 Receive FIFO Not Empty Flag (RNE) (read-only, noninterruptible)  
The receive FIFO not empty flag (RNE) is a read-only bit that is set whenever the receive FIFO  
contains one or more entries of valid data and is cleared when it no longer contains any valid data.  
This bit can be polled when using programmed I/O to remove remaining bytes of data from the  
receive FIFO because DMA service and CPU interrupt requests are only made when four or more  
bytes reside within the FIFO (3, 2, or 1 bytes may remain at the end of a frame). This bit does not  
request an interrupt.  
11.12.12.3 SSP Busy Flag (BSY) (read-only, noninterruptible)  
The SSP busy (BSY) flag is a read-only bit that is set when the SSP is actively transmitting and/or  
receiving data, and is cleared when the SSP is idle or disabled (SSE=0). This bit does not request  
an interrupt.  
11.12.12.4 Transmit FIFO Service Request Flag (TFS) (read-only, maskable  
interrupt)  
The transmit FIFO service request flag (TFS) is a read-only bit that is set when the transmit FIFO is  
nearly empty and requires service to prevent an underrun. TFS is set whenever the transmit FIFO  
has four or fewer entries of valid data (half-full or less), and is cleared when it has five or more  
entries of valid data. When the TFS bit is set, an interrupt request is made unless the transmit FIFO  
interrupt request enable (TIE) bit is cleared. The state of TFS is also sent to the DMA controller,  
and can be used to signal a DMA service request. Note that TIE has no effect on the generation of  
the DMA service request. After the DMA or CPU fills the FIFO such that four or more locations  
are filled within the transmit FIFO, the TFS flag (and the service request and/or interrupt) is  
automatically cleared.  
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Peripheral Control Module  
11.12.12.5 Receive FIFO Service Request Flag (RFS) (read-only, maskable  
interrupt)  
The receive FIFO service request flag (RFS) is a read-only bit that is set when the receive FIFO is nearly  
filled and requires service to prevent an overrun. RFS is set whenever the receive FIFO has four or more  
entries of valid data (half-full or more), and is cleared when it has three or fewer (less than half-full)  
entries of data. When the RFS bit is set, an interrupt request is made unless the receive FIFO interrupt  
request enable (RIE) bit is cleared. The state of RFS is also sent to the DMA controller, and can be used  
to signal a DMA service request. Note that RIE has no effect on the generation of the DMA service  
request. After the DMA or CPU fills the FIFO such that four or more locations are filled within the  
receive FIFO, the RFS flag (and the service request and/or interrupt) is automatically cleared.  
11.12.12.6 Receiver Overrun Status (ROR) (read/write, nonmaskable interrupt)  
The receiver overrun status bit (ROR) is a read/write bit that is set when the receive logic attempts  
to place data into the receive FIFO after it has been completely filled. Each time a new piece of  
data is received, the set signal to the ROR bit is asserted, and the newly received data is discarded.  
This process is repeated for each new piece of data received until at least one empty FIFO entry  
exists. When the ROR bit is set, an interrupt request is made.  
The following table shows the bit locations corresponding to the status and flag bits within the SSP  
status register. All bits are read-only except ROR, which is read/write. Writes to TNF, RNE, BSY, TFS,  
and RFS have no effect. The reset state of ROR is unknown (indicated by a question mark) and must be  
initialized before enabling the SSP. Note that writes to reserved bits are ignored and reads return zeros.  
Read/Write &  
Address: 0h 8007 0074  
SSP Status Register: SSSR  
Read-Only  
Bit  
15  
14  
13  
0
12  
0
11  
Reserved  
0
10  
0
9
8
7
6
ROR  
?
5
RFS  
0
4
TFS  
0
3
BSY  
0
2
RNE  
0
1
TNF  
1
0
Res  
0
Reset  
0
0
0
0
0
Bit  
Name  
Description  
0
Reserved.  
1
TNF  
RNE  
BSY  
TFS  
Transmit FIFO not full (read-only).  
0 – Transmit FIFO is full.  
1 – Transmit FIFO is not full.  
2
3
4
Receive FIFO not empty (read-only).  
0 – Receive FIFO is empty.  
1 – Receive FIFO is not empty.  
SSP busy flag (read-only).  
0 – SSP is idle or disabled.  
1 – SSP is currently transmitting and/or receiving a frame (no interrupt generated).  
Transmit FIFO service request (read-only).  
0 – Transmit FIFO is more than half-full (five or more entries filled) or SSP disabled.  
1 – Transmit FIFO is half-full or less (four or fewer entries filled) and SSP operation is  
enabled, DMA service request signalled, interrupt request signalled if not masked (if TIE=1).  
5
6
RFS  
Receive FIFO service request (read-only).  
0 – Receive FIFO is less than half-full (three or fewer entries filled) or SSP disabled.  
1 – Receive FIFO is half-full or more (four or more entries filled) and SSP operation is  
enabled, DMA service request signalled, interrupt request signalled if not masked (if RIE=1).  
ROR  
Receive FIFO overrun.  
0 – Receive FIFO has not experienced an overrun.  
1 – Receive logic attempted to place data into receive FIFO while it was full, request interrupt.  
15..7  
Reserved.  
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11.12.13 MCP Register Locations  
Table 11-19 shows the registers associated with the MCP and the physical addresses used to access them.  
Table 11-19. MCP Control, Data, and Status Register Locations  
Address  
0h 8006 0000  
Name  
MCCR0  
Description  
MCP control register 0  
0h 8006 0004  
Reserved  
0h 8006 0008  
MCDR0  
MCDR1  
MCDR2  
MCP data register 0  
MCP data register 1  
MCP data register 2  
Reserved  
0h 8006 000C  
0h 8006 0010  
0h 8006 0014  
0h 8006 0018  
MCSR  
MCP status register  
Reserved  
0h 8006 001C – 0h 8006 005C  
Note: MCCR1 resides within the same address space as the PPC.  
0h 9006 0030 MCCR1 MCP control register 1  
11.12.14 SSP Register Locations  
Table 11-20 shows the registers associated with the SSP and the physical addresses used to access them.  
Table 11-20. SSP Control, Data, and Status Register Locations  
Address  
0h 8007 0060  
Name  
SSCR0  
Description  
SSP control register 0  
0h 8007 0064  
SSCR1  
SSP control register 1  
Reserved  
0h 8007 0068  
0h 8007 006C  
SSDR  
SSP data register  
Reserved  
0h 8007 0070  
0h 8007 0074  
SSSR  
SSP status register  
Reserved  
0h 8007 0078 – 0h 8007 FFFF  
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Peripheral Control Module  
11.13  
Peripheral Pin Controller (PPC)  
The peripheral pin controller (PPC) takes individual control of the LCD’s and serial port 1..4’s pins  
when one or more of the units are disabled, allowing the user to utilize them as general-purpose  
digital I/O pins to communicate to off-chip resources. When controlled by the PPC, peripheral  
control module (PCM) pins operate similarly to GPIO pins except that they cannot perform edge  
detection and interrupt generation. The PPC is also used to specify the direction of the peripherals’  
pins when sleep mode is entered.  
Note that serial ports 1..3 contain individual enables for their transmit and receive serial engines.  
Thus, if only half-duplex transmission is needed, one pin can be used for serial communication and  
the other for digital I/O communication. Also note that serial port 0’s pins are dedicated to the USB  
device controller (UDC), which uses the pins to drive a differential transceiver, preventing them  
from being used as digital I/O pins when the UDC is disabled.  
11.13.1 PPC Operation  
Following a hardware reset of the SA-1100 (nRESET asserted then negated), all peripheral control  
module units are disabled, giving control of their pins to the PPC (except serial port 0). The PPC, in  
turn, configures all peripheral pins it controls as inputs. Once reset is negated, the user should  
program the peripherals as soon as possible, and configure the pins of any peripheral that is not  
usable to function as general-purpose I/O signals. This should be done quickly to limit the amount  
of power consumed at startup because pins that are intended to function as outputs within the  
system are initially configured as inputs, and the receiving device to which they are connected will  
float and consume power.  
The PPC contains special resources to limit off-chip power consumption during and immediately  
following the assertion of sleep mode. The PPC contains a sleep mode direction register, which is  
programmed by the user, and individually configures 22 of the peripherals’ pins either as inputs or  
outputs during sleep mode. When configured as an output, the pin is forced low in sleep mode. This  
special register is required because the first action taken when sleep mode is entered is the assertion  
of reset to all the peripherals, which would, in turn, errantly configure all peripheral pins as inputs.  
The sleep mode direction register is not reset; the user can maintain the correct direction  
programmed for each of the peripherals’ pins while in sleep mode. When sleep mode is exited, the  
user can then reprogram the peripherals and the PPC registers to resume control of the peripherals’  
pins. To keep the same pin direction and state after sleep mode has been negated but before the user  
reprograms the peripherals, the system control module’s power manager maintains the peripherals’  
pin direction and state following sleep negation until the peripheral control hold bit (PSSR:PH),  
located in the power manager, is cleared (by writing a one to it). Therefore, the pin direction and  
state established during sleep using the sleep mode direction register remains intact following the  
negation of sleep until the PH bit is cleared. Once PH is cleared, control of the peripherals’ pins is  
given back to the individual peripherals and to the PPC unit.  
Most of the SA-1100’s peripherals can take control of one or more GPIO pins (which are normally  
controlled within the system control module) to act as input or output triggers, or to drive or supply  
clocks to the peripherals. The GPIO unit contains a GPIO alternate function register (GAFR) that  
the user must program to give control of the GPIO pins to the individual peripheral units for each  
of the alternate functions. The user must also program the GPIO pin direction register (GPDR) for  
the corresponding pins that are used by the peripheral units. The GPIO pin alternate functions are  
then enabled within the individual peripherals using a control bit. However, two control bits exist  
within the PPC that configure six of the GPIO unit’s pins for peripheral alternate functions.  
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Serial port 1 and serial port 4 both contain two serial-to-parallel engines that operate independently.  
However, because each port contains only one set of serial pins, the user can assign these pins to  
only one of the two protocols at a time. To allow the user to utilize both protocols, the PPC can  
assign one of its two serial-to-parallel engines to the pins that are dedicated to the port, and the  
other to a set of GPIO pins. Serial port 1 contains an SDLC and a UART. By setting a bit in the  
PPC and the appropriate GAFR and GPDR bits in the GPIO unit, SDLC operation defaults to the  
TXD1 and RXD1 pins, and the UART transmits via the GPIO<14> pin and receives via the  
GPIO<15> pin. Likewise, serial port 4 contains the MCP and the SSP synchronous serial engines.  
The user can configure the PPC and GPIO units to cause the MCP to default to the TXD4, RXD4,  
SCLK, and SFRM pins, and the SSP is assigned to GPIO<10> for transmit, GPIO<11> for receive,  
GPIO<12> for serial clock, and GPIO<13> for serial frame.  
When the SA-1100 is reset or enters sleep mode, the GPIO unit’s registers are reset, which gives  
control of the GPIO pins back to the system control module.  
11.13.2 PPC Register Definitions  
There are five registers within the PPC: one pin direction register, one pin state register, one pin  
assignment register, one sleep mode pin direction register, and one pin flag register.  
11.13.3 PPC Pin Direction Register  
Pin direction is controlled by programming the PPC pin direction register (PPDR). The PPDR  
contains individual direction control bits for 22 of the 24 peripheral pins. Serial port 0 has  
dedicated pins (UDC+ and UDC-) that are not controlled by the PPC when the UDC is disabled.  
Each bit is used only if the corresponding peripheral that it controls is disabled. Provided the  
corresponding peripheral is disabled, if the direction bit is programmed to a one, the pin is an  
output. If it is programmed to a zero, it is an input. Following reset, all peripherals are disabled,  
which causes the PPC to take control of all of their pins. Serial ports 1..3 contain individual enables  
for their transmit and receive serial engines. Thus, if only half-duplex transmission is needed, one  
pin can be used for serial communication and the other for digital I/O communication. Note that  
PPDR is reset such that all the pins are configured as inputs. For reserved bits, writes are ignored  
and reads return zero. The following table shows the location of each pin direction bit and to which  
peripheral pin it corresponds.  
Address: 0h 9006 0000  
PPDR: PPC Pin Direction Register  
Read/Write  
Bit  
Reset  
Bit  
31  
30  
29  
0
28  
0
27  
26  
25  
24  
23  
22  
21  
SFRM  
0
20  
SCLK  
0
19  
RXD4  
0
18  
TXD4  
0
17  
RXD3  
0
16  
TXD3  
0
Reserved  
0
0
0
0
0
0
0
0
15  
RXD2  
0
14  
TXD2  
0
13  
RXD1  
0
12  
TXD1  
0
11  
10  
9
8
7
6
5
4
3
2
1
0
LDD  
<7>  
LDD  
<6>  
LDD  
<5>  
LDD  
<4>  
LDD  
<3>  
LDD  
<2>  
L_  
BIAS  
L_  
FCLK  
L_  
LCLK  
L_  
PCLK  
LDD  
<1>  
LDD  
<0>  
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
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Bit  
7..0  
Name  
Description  
LDD<7:0 LCD data pin direction.  
>
0 – If LCD controller disabled, LCD data pin configured as general-purpose input.  
1 – If LCD controller disabled, LCD data pin configured as general-purpose output.  
8
L_PCLK  
L_LCLK  
L_FCLK  
L_BIAS  
TXD1  
RXD1  
TXD2  
RXD2  
TXD3  
RXD3  
TXD4  
RXD4  
SCLK  
SFRM  
LCD pixel clock pin direction.  
0 – If LCD controller disabled, LCD pixel clock pin configured as general-purpose input.  
1 – If LCD controller disabled, LCD pixel clock pin configured as general-purpose output.  
9
LCD line clock pin direction.  
0 – If LCD controller disabled, LCD line clock pin configured as general-purpose input.  
1 – If LCD controller disabled, LCD line clock pin configured as general-purpose output.  
10  
11  
LCD frame clock pin direction.  
0 – If LCD controller disabled, LCD frame clock pin configured as general-purpose input.  
1 – If LCD controller disabled, LCD frame clock pin configured as general-purpose output.  
LCD AC bias pin direction.  
0 – If LCD controller disabled, LCD ac bias pin configured as general-purpose input.  
1 – If LCD controller disabled, LCD ac bias pin configured as general-purpose output.  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
31..22  
Serial port 1: SDLC/UART transmit pin direction.  
0 – If serial port 1 transmitter disabled, transmit pin configured as general-purpose input.  
1 – If serial port 1 transmitter disabled, transmit pin configured as general-purpose output.  
Serial port 1: SDLC/UART receive pin direction.  
0 – If serial port 1 receiver disabled, receive pin configured as general-purpose input.  
1 – If serial port 1 receiver disabled, receive pin configured as general-purpose output.  
Serial port 2: IPC transmit pin direction.  
0 – If serial port 2 transmitter disabled, transmit pin configured as general-purpose input.  
1 – If serial port 2 transmitter disabled, transmit pin configured as general-purpose output.  
Serial port 2: IPC receive pin direction.  
0 – If serial port 2 receiver disabled, receive pin configured as general-purpose input  
1 – If serial port 2 receiver disabled, receive pin configured as general-purpose output  
Serial port 3: UART transmit pin direction.  
0 – If serial port 3 transmitter disabled, transmit pin configured as general-purpose input  
1 – If serial port 3 transmitter disabled, transmit pin configured as general-purpose output  
Serial port 3: UART receive pin direction.  
0 - If serial port 3 receiver disabled, receive pin configured as general-purpose input.  
1 - If serial port 3 receiver disabled, receive pin configured as general-purpose output.  
Serial port 4: MCP/SSP transmit pin direction.  
0 - If serial port 4 disabled, transmit pin configured as general-purpose input.  
1 - If serial port 4 disabled, transmit pin configured as general-purpose output.  
Serial port 4: MPC/SSP receive pin direction.  
0 – If serial port 4 disabled, receive pin configured as general-purpose input.  
1 – If serial port 4 disabled, receive pin configured as general-purpose output.  
Serial port 4: MPC/SSP serial clock pin direction.  
0 – If serial port 4 disabled, serial clock pin configured as general-purpose input.  
1 – If serial port 4 disabled, serial clock pin configured as general-purpose output.  
Serial port 4: MPC/SSP serial frame pin direction.  
0 – If serial port 4 disabled, serial frame pin configured as general-purpose input.  
1 – If serial port 4 disabled, serial frame pin configured as general-purpose output.  
Reserved.  
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11.13.4 PPC Pin State Register  
Pin state is both monitored and controlled by reading/writing the PPC pin state register (PPSR). The  
PPSR contains 1 state bit for each of the 22 peripheral pins. This register may be read at any time to  
determine the current state of all peripheral pins, even when pins are controlled by the peripheral  
rather than the PPC. If a peripheral is disabled and its corresponding pin direction is programmed as  
an output in the PPDR, its PPSR bit is used to control the state of the peripheral pin. Writing a zero to  
the pin’s state bit causes the pin to be forced low, and writing a one causes the pin to be forced high.  
Writing a value to a pin state bit that is an input or is not under the control of the PPC has no effect. To  
alter the state of an output pin, the user should first read the PPSR, then logically AND the value read  
with a mask, which contains ones in every bit position except the one the user wishes to clear. To set a  
pin, the user should logically OR the value read with a mask, which contains zeros in every bit  
position except the one the user wishes to set. This mechanism allows the user to set or clear  
individual pins without changing the state of other pins that are configured as outputs.  
Serial port 2 contains two bits that control the polarity of data input via the receive pin (RXD2) and  
data output via the transmit pin (TXD2). The user must ensure that these polarity bits are set  
(RXP = TXP = 1), which selects true or noninverted data before using TXD2 or RXD2 as GPIO  
pins.  
Note that PPSR is implemented as two separate registers. A write to PPSR addresses one of the  
registers and is used to set and clear pins configured as GPIO outputs, while a read addresses the  
other register that is used to store and monitor pin state. The register used to store pin state contains  
logic to synchronize the signal input from the pin to allow the user to read it. The pins are sampled  
at a rate of 7.3728 MHz; each synchronization cycle takes 135.6 ns. Depending on the CPU  
frequency programmed by the user, after changing the state of an output pin via a write, one or  
more dummy read cycle waitstates may need to be inserted to allow the value to be output to the  
pin and to allow the synchronizer to resample the pin.  
The following table shows the location of each pin state bit and to which peripheral pin it  
corresponds. Note that this register is not reset and that for reserved bits, writes are ignored and  
reads return zero.  
Address: 0h 9006 0004  
PPSR: PPC Pin StateRegister  
Read/Write  
Bit  
Reset  
Bit  
31  
30  
29  
0
28  
0
27  
26  
0
25  
24  
23  
22  
0
21  
SFRM  
0
20  
SCLK  
0
19  
RXD4  
0
18  
TXD4  
0
17  
RXD3  
0
16  
TXD3  
0
Reserved  
0
0
0
0
0
0
15  
RXD2  
0
14  
TXD2  
0
13  
RXD1  
0
12  
TXD1  
0
11  
10  
9
8
7
6
5
4
3
2
1
0
L_  
L_  
L_  
LDD  
<7>  
LDD  
<6>  
LDD  
<5>  
LDD  
<4>  
LDD  
<3>  
LDD  
<2>  
L_  
FCK  
LDD  
<1>  
LDD  
<0>  
BIAS  
LCK  
PCK  
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
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Peripheral Control Module  
Bit  
7..0  
Name  
Description  
LDD<7:0 LCD data pin state.  
>
Read – Current state of LCD data pin returned.  
Write – If LCD disabled and pin configured as an output, drive value to LCD data pin.  
8
L_PCLK  
L_LCLK  
L_FCLK  
L_BIAS  
TXD1  
LCD pixel clock pin state.  
Read – Current state of LCD pixel clock pin returned.  
Write – If LCD disabled and pin configured as an output, drive value to LCD pixel clock pin.  
9
LCD line clock pin state.  
Read – Current state of LCD line clock pin returned.  
Write – If LCD disabled and pin configured as an output, drive value to LCD line clock pin.  
10  
11  
12  
LCD frame clock pin state.  
Read – Current state of LCD frame clock pin returned.  
Write – If LCD disabled and pin configured as an output, drive value to LCD frame clock pin.  
LCD AC bias pin state.  
Read – Current state of LCD AC bias pin returned.  
Write – If LCD disabled and pin configured as an output, drive value to LCD AC bias pin.  
Serial port 1: SDLC/UART transmit pin state.  
Read – Current state of serial port 1 transmit pin returned.  
Write – If serial port 1 transmitter disabled and pin configured as an output, drive value  
to transmit pin.  
13  
RXD1  
TXD2  
RXD2  
TXD3  
RXD3  
TXD4  
RXD4  
SCLK  
SFRM  
Serial port 1: SDLC/UART receive pin state.  
Read – Current state of serial port 1 receive pin returned.  
Write – If serial port 1 receiver disabled and pin configured as an output, drive value to  
receive pin.  
14  
Serial port 2: IPC transmit pin state.  
Read – Current state of serial port 1 transmit pin returned.  
Write – If serial port 2 transmitter disabled and pin configured as an output, drive value  
to transmit pin.  
15  
Serial port 2: IPC receive pin state.  
Read – Current state of serial port 2 receive pin returned.  
Write – If serial port 2 receiver disabled and pin configured as an output, drive value to  
receive pin.  
16  
Serial port 3: UART transmit pin state.  
Read – Current state of serial port 3 transmit pin returned.  
Write – If serial port 3 transmitter disabled and pin configured as an output, drive value  
to transmit pin.  
17  
Serial port 3: UART receive pin state.  
Read – Current state of serial port 3 receive pin returned.  
Write – If serial port 3 receive disabled and pin configured as an output, drive value to  
receive pin.  
18  
Serial port 4: MCP/SSP transmit pin state.  
Read – Current state of serial port 4 transmit pin returned.  
Write – If serial port 4 transmitter disabled and pin configured as an output, drive value  
to transmit pin.  
19  
Serial port 4: MCP/SSP receive pin state.  
Read – Current state of serial port 4 receive pin returned.  
Write – If serial port 4 receive disabled and pin configured as an output, drive value to  
receive pin.  
20  
Serial port 4: MCP/SSP serial clock pin state.  
Read – Current state of serial port 4 serial clock pin returned.  
Write – If serial port 4 disabled and pin configured as an output, drive value to serial  
clock pin.  
21  
Serial port 4: MCP/SSP serial frame pin state.  
Read – Current state of serial port 4 serial frame pin returned.  
Write – If serial port 4 disabled and pin configured as an output, drive value to serial  
frame pin.  
31..22  
Reserved.  
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11.13.5 PPC Pin Assignment Register  
The UART in serial port 1 and the SSP in serial port 4 can be reassigned to GPIO pins using the  
PPC pin assignment register (PPAR). The PPAR contains two bits that control the reassignment of  
each serial engine to an individual set of GPIO pins.  
11.13.5.1 UART Pin Reassignment (UPR)  
The UART pin reassignment (UPR) bit is used to select whether serial port 1’s UART is assigned  
to GPIO pins 14 and 15. When UPR=0, serial port 1 uses its TXD1 and RXD1 pins, and the  
SDLC/UART select (SUS) bit is used to select which protocol is enabled. When UPR=1, SUS is  
ignored, serial port 1 defaults to SDLC operation using the TXD1 and RXD1 pins, and the UART  
is configured to use GPIO<14> for transmit and GPIO<15> for receive. Note that the user must set  
bits 14 and 15 in the GPIO alternate function register (GAFR) as well as set bit 14 and clear bit 15  
in the GPIO pin direction register (GPDR). See the Section 9.1, “General-Purpose I/O” on  
11.13.5.2 SSP Pin Reassignment (SPR)  
The SSP pin reassignment (SPR) bit is used to select whether serial port 4’s SSP is assigned to GPIO pins  
10 through 13. When SPR=0, serial port 4 uses its TXD4, RXD4, SCLK, and SFRM pins; the MCP  
enable (MCE) and SSP enable (SSE) bits are used to select which protocol is enabled (MCE has  
precedence over SSE). When SPR=1, MCE and SSE must both be set; serial port 4 defaults to MCP  
operation using the TXD4, RXD4, SCLK, and SFRM pins, and the SSP is configured to use GPIO<10>  
for transmit, GPIO<11> for receive, GPIO<12> for serial clock, and GPIO<13> for serial frame. Note  
that the user must set bits 10 through 13 in the GPIO alternate function register (GAFR) as well as set bits  
10, 12, and 13 and clear bit 11 in the GPIO pin direction register (GPDR). See the Section 9.1,  
The following table shows the location of the two pin reassignment bits. Note that for reserved bits,  
writes are ignored and reads return zero. Both control bits are cleared to zero following a reset of  
the SA-1100, giving control of all GPIO pins to the system control module.  
Address: 0h 9006 0008  
PPAR: PPC Pin Assignment Register  
Read/Write  
Bit  
Reset  
Bit  
31  
30  
29  
28  
0
27  
0
26  
25  
Reserved  
0
24  
23  
22  
21  
0
20  
0
19  
0
18  
SPR  
0
17  
16  
Reserved  
0
0
0
0
0
0
0
0
1
0
0
0
0
15  
0
14  
Reserved  
0
13  
0
12  
UPR  
0
11  
0
10  
0
9
0
8
7
6
5
4
3
2
0
Reserved  
Reset  
0
0
0
0
0
0
Bit  
Name  
Description  
11..0  
Reserved.  
UART pin reassignment.  
12  
UPR  
0 – No pin reassignment made, GPIO<14-15> controlled by GPIO unit, serial port 1  
UART assigned to TXD1 and RXD1 if SUS=1.  
1 – Pin reassignment made, serial port 1 defaults to SDLC operation (SUS ignored),  
UART transmit assigned to GPIO<14> and receive to GPIO<15>, GAFR and GPDR  
must be configured in GPIO unit.  
17..13  
18  
Reserved.  
SPR  
SSP pin reassignment.  
0 – No pin reassignment made, GPIO<10-13> controlled by GPIO unit, serial port 4  
SSP assigned to TXD4, RXD4, SCLK, and SFRM if MCE=0 and SSE=1.  
1– Pin reassignment made, serial port 4 defaults to MCP operation, SSP transmit  
assigned to GPIO<10>, receive to GPIO<11>, serial clock to GPIO<12>, and serial  
frame to GPIO<13>, GAFR and GPDR must be configured in GPIO unit.  
31..19  
Reserved.  
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Peripheral Control Module  
11.13.6 PPC Sleep Mode Pin Direction Register  
When sleep mode is entered, reset is asserted to all of the SA-1100’s peripherals and to the PPC unit.  
The PPC pin direction register is cleared during a hard, soft, or sleep reset, causing the peripheral pins  
under the PPC’s control to be configured as inputs. If this register were also used to determine pin  
direction during sleep, the pins would all be configured as inputs. This action would cause any off-chip  
device that expects data to be output from the SA-1100 to burn power during sleep because its input  
would float. The sleep mode pin direction register (PSDR) prevents this undesired power consumption  
by allowing the user to establish peripheral pin direction during and immediately following sleep mode.  
When sleep mode is entered, both the peripherals and the PPC are reset; however, PSDR is not reset  
like PPDR. Once the user programs PSDR, it retains its data after sleep mode is entered and reset is  
asserted. The power manager uses the values in PSDR to determine the direction and state of the 22  
peripheral pins. When a sleep mode direction bit is programmed to a zero, the corresponding pin is  
configured as an output and is driven low (zero). If it is programmed to a one, it is an input. The  
power manager latches the contents of PSDR before VDD is removed from the SA-1100 to maintain  
the peripheral pin direction and state after the main power supply is removed. Once VDD is removed,  
the data in PSDR is lost and must be reprogrammed after exiting sleep mode. The power manager  
contains a control bit called the peripheral control hold (PSSR:PH). This bit is set upon exit from  
sleep mode and indicates that the peripheral pins are being held in their sleep state. Following sleep,  
the user should first reprogram the peripherals and the PPC, then clear PH (by writing a one to it) in  
order to give control of the pins back to the peripheral units. Note that sleep mode invocation causes  
RPP to be cleared so that the pins are once again held in their sleep state until the user can set RPP.  
Because the peripherals are reset when sleep mode is entered, serial port 2’s transmit and receive  
pin (TXD2 and RXD2) polarity bits (TXP and RXP) are both reset to one, which configures  
transmit and receive data as true or noninverted data. Thus the user need not reprogram these bits  
prior to the invocation of sleep mode.  
Note that PPSR is initialized only by a hardware or power-on reset (negation of the nRESET pin). It is  
not affected by a software reset or a reset that occurs as a result of the SA-1100 entering sleep mode.  
Also note that for reserved bits, writes are ignored and reads return zero. The following table shows  
the location of each sleep mode pin direction bit and to which peripheral pin it corresponds.  
Address: 0h 9006 000C  
PSDR: PPC Sleep Mode Pin Direction Register  
Read/Write  
Bit  
Hard Reset  
Bit  
31  
30  
29  
0
28  
0
27  
26  
25  
24  
23  
22  
21  
SFRM  
1
20  
SCLK  
1
19  
RXD4  
1
18  
TXD4  
1
17  
RXD3  
1
16  
TXD3  
1
Reserved  
0
0
0
0
0
0
0
0
15  
14  
TXD2  
1
13  
RXD1  
1
12  
TXD1  
1
11  
10  
9
8
7
6
5
4
3
2
1
0
L_  
L_  
L_  
L_  
LDD  
<7>  
LDD  
<6>  
LDD  
<5>  
LDD  
<4>  
LDD  
<3>  
LDD  
<2>  
RXD  
2
LDD  
<1>  
LDD  
<0>  
BIAS  
FCLK  
LCLK  
PCLK  
Hard Reset  
1
1
1
1
1
1
1
1
1
1
1
1
1
11-190  
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Peripheral Control Module  
Bit  
7..0  
Name  
Description  
LDD<7:0 LCD data sleep mode pin direction.  
>
0 – LCD data pin configured as output and is driven low during sleep.  
1 – LCD data pin configured as input during sleep.  
8
L_PCLK  
L_LCLK  
L_FCLK  
L_BIAS  
TXD1  
LCD pixel clock sleep mode pin direction.  
0 – LCD pixel clock pin configured as output and is driven low during sleep.  
1 – LCD pixel clock pin configured as input during sleep.  
9
LCD line clock sleep mode pin direction.  
0 – LCD line clock pin configured as output and is driven low during sleep.  
1 – LCD line clock pin configured as input during sleep.  
10  
11  
12  
13  
14  
15  
16  
17  
18  
LCD frame clock sleep mode pin direction.  
0 – LCD frame clock pin configured as output and is driven low during sleep.  
1 – LCD frame clock pin configured as input during sleep.  
LCD ac bias sleep mode pin direction.  
0 – LCD ac bias pin configured as output and is driven low during sleep.  
1 – LCD ac bias pin configured as input during sleep.  
Serial port 1: SDLC/UART transmit sleep mode pin direction.  
0 – Transmit pin configured as output and is driven low during sleep.  
1 – Transmit pin configured as input during sleep.  
RXD1  
Serial port 1: SDLC/UART receive sleep mode pin direction.  
0 – Receive pin configured as output and is driven low during sleep.  
1 – Receive pin configured as input during sleep.  
TXD2  
Serial port 2: IPC transmit sleep mode pin direction.  
0 – Transmit pin configured as output and is driven low during sleep.  
1 – Transmit pin configured as input during sleep.  
RXD2  
Serial port 2: IPC receive sleep mode pin direction.  
0 – Receive pin configured as output and is driven low during sleep.  
1 – Receive pin configured as input during sleep.  
TXD3  
Serial port 3: UART transmit sleep mode pin direction.  
0 – Transmit pin configured as output and is driven low during sleep.  
1 – Transmit pin configured as input during sleep.  
RXD3  
Serial port 3: UART receive sleep mode pin direction.  
0 – Receive pin configured as output and is driven low during sleep.  
1 – Receive pin configured as input during sleep.  
TXD4  
Serial port 4: MCP/SSP transmit sleep mode pin direction.  
0 – Transmit pin configured as output and is driven low during sleep.  
1 – Transmit pin configured as input during sleep.  
19  
RXD4  
SCLK  
SFRM  
Serial port 4: MCP/SSP receive sleep mode pin direction.  
0 – Receive pin configured as output and is driven low during sleep.  
1 – Receive pin configured as input during sleep.  
20  
Serial port 4: MCP/SSP serial clock sleep mode pin direction.  
0 – Serial clock pin configured as output and is driven low during sleep.  
1 – Serial clock pin configured as input during sleep.  
21  
Serial port 4: MCP/SSP serial frame sleep mode pin direction.  
0 – Serial frame pin configured as output and is driven low during sleep.  
1 – Serial frame pin configured as input during sleep.  
31..22  
Reserved.  
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Peripheral Control Module  
11.13.7 PPC Pin Flag Register  
The PPC pin flag register (PPFR) is used to determine which peripherals are currently under the  
control of the PPC unit. The eight read-only flags denote whether or not each of the peripherals  
(except serial port 0) is enabled or is disabled and being controlled by the PPC. Note that serial  
ports 1..3 contain individual enables for their transmit and receive serial engines. Thus, separate  
flag bits exist for their transmit and receive pins. When a flag is set, it indicates that the  
corresponding peripheral is disabled and is controlled by the PPC; when it is cleared, it indicates  
that the peripheral is enabled and its pins are being used for serial transmission (serial ports 1..4) or  
for LCD operation. Note that for reserved bits, writes are ignored and reads return zero. The  
following table shows the location of each pin flag bit and to which peripheral pin it corresponds.  
Address: 0h 9006 0010  
PPFR: PPC Pin Flag Register  
Read-Only  
Bit  
31  
30  
29  
28  
27  
26  
25  
Reserved  
0
24  
23  
22  
0
21  
20  
19  
18  
SP4  
1
17  
16  
SP3  
RX  
SP3  
TX  
Reset  
Bit  
0
0
0
0
0
0
0
8
0
7
0
5
0
4
0
3
1
1
15  
14  
13  
12  
11  
10  
9
0
6
2
0
1
0
LCD  
1
SP2  
RX  
SP2  
TX  
SP1  
RX  
SP1  
TX  
Reserved  
0
Reset  
1
1
1
1
0
0
0
0
0
0
0
0
Bit  
Name  
LCD  
Description  
0
LCD controller flag (read-only).  
0 – LCD controller enabled.  
1 – LCD disabled, PPC currently controlling all 12 of its pins: LDD<7:0>, L_PCLK,  
L_LCLK, L_FCLK, L_BIAS.  
11..1  
12  
Reserved.  
SP1 TX  
Serial port 1: SDLC/UART transmit flag (read-only).  
0 – SDLC or UART transmit enabled.  
1 – SDLC and UART transmitters disabled, PPC currently controlling the transmit pin:  
TXD1.  
13  
14  
15  
SP1 RX  
SP2 TX  
SP2 RX  
Serial port 1: SDLC/UART receive flag (read-only).  
0 – SDLC or UART receive enabled.  
1 – SDLC and UART receivers disabled, PPC currently controlling the receive pin:  
RXD1.  
Serial port 2: ICP transmit flag (read-only).  
0 – HSSP or UART transmit enabled.  
1– HSSP and UART transmitters disabled, PPC currently controlling the transmit pin:  
TXD2.  
Serial port 2: ICP receive flag (read-only).  
0 – HSSP or UART receive enabled.  
1 – HSSP and UART receivers disabled, PPC currently controlling the receive pin:  
RXD2.  
16  
17  
18  
SP3 TX  
SP3 RX  
SP4  
Serial port 3: UART transmit flag (read-only).  
0 – UART transmit enabled.  
1 – UART transmit disabled, PPC currently controlling the transmit pin: TXD3.  
Serial port 3: UART receive flag (read-only).  
0 – UART receive enabled.  
1 – UART receive disabled, PPC currently controlling the receive pin: RXD3.  
Serial port 4: MCP/SSP flag (read-only).  
0 – MCP or SSP enabled.  
1– MCP and SSP disabled, PPC currently controlling all 4 of its pins:  
TXD4, RXD4, SCLK, SFRM.  
31..19  
Reserved.  
11-192  
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Peripheral Control Module  
11.13.8 PPC Register Locations  
Table 11-21 shows the registers associated with the PPC and the physical addresses used to access  
them. Note that serial port 2 (ICP) has implemented HSSP control register 2 and serial port 4  
(MCP) has also implemented MCP control register 1 within the PPC’s address space at 0h 9006  
0028 and 0h 9006 0030 respectively. The user should ensure that these registers are not  
accidentally written by any PPC routines that may attempt to write to all of the PPC’s address  
space, including its reserved registers during initialization.  
Table 11-21. PPC Control and Flag Register Locations  
Address  
Name  
PPDR  
Description  
PPC pin direction register  
0h 9006 0000  
0h 9006 0004  
0h 9006 0008  
0h 9006 000C  
0h 9006 0010  
PPSR  
PPAR  
PSDR  
PPFR  
PPC pin state register  
PPC pin assignment register  
PPC sleep mode direction register  
PPC pin flag register  
0h 9006 0014 –  
0h 9006 FFFF  
Reserved  
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DC Parameters  
12  
This chapter defines the dc parameters for the Intel® StrongARM® SA-1100 Microprocessor  
(SA-1100).  
12.1  
Absolute Maximum Ratings  
Table 12-1 lists the absolute maximum ratings for the SA-1100.  
Table 12-1. SA-1100 DC Maximum Ratings  
Symbol  
VDD  
Parameter  
Min  
VSS – 0.5  
Max  
Units  
Note  
Core supply voltage  
VSS + 2.1  
V
1
MIN(VSS – 0.05,  
VDD – 0.3)  
VDDX  
I/O voltage  
VSS + 3.6  
V
1
Vip  
Voltage applied to any pin  
Voltage applied to *XTAL pins  
Storage temperature  
VSS – 0.5  
VSS + 3.6  
V
V
1
1
1
Vip (*XTAL)  
Ts  
0
1
– 40  
125  
°C  
NOTE:  
1. These are stress SA-1100 ratings only. Exceeding the absolute maximum ratings may permanently  
damage the device. Operating the device at absolute maximum ratings for extended periods may affect  
device reliability.  
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DC Parameters  
12.2  
DC Operating Conditions  
Table 12-2 lists the functional operating dc parameters for the SA-1100.  
Table 12-2. SA-1100 DC Operating Conditions  
Symbol  
Parameter  
Min  
Nom  
Max  
VDDX  
Units  
Notes  
Vihc  
IC input high voltage  
0.8 × VDDX  
V
V
V
V
1, 2  
1, 2  
1, 3  
1, 3  
Vilc  
IC input low voltage  
0.0  
10  
0.2 × VDDX  
Vohc  
Volc  
Iohc  
Iolc  
Ta  
OCZ output high voltage  
OCZ output low voltage  
High-level output current  
Low-level output current  
Ambient operating temperature  
IC input leakage current  
0.8 × VDDX  
VDDX  
0.0  
0
0.2 × VDDX  
– 2  
2
mA  
mA  
°C  
70  
Iin  
µA  
Output high current  
(Vout = VDD – 0.4 V)  
Ioh  
Iol  
2
2
mA  
mA  
Output high current  
(Vout = VSS + 0.4 V)  
Cin  
Input capacitance  
HBM model ESD  
5
1
pF  
4
ESD  
KV  
NOTES:  
1. Voltages measured with respect to VSS.  
2. IC – CMOS-level inputs (includes IC and ICOCZ pin types).  
3. OCZ – Output, CMOS levels, tristateable.  
4. Parameter guaranteed by design  
Not tested at this time  
12-2  
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DC Parameters  
12.3  
Power Supply Voltages and Currents  
Table 12-3 specifies the power supply voltages and currents for the SA-1100. For power supply  
voltages and currents for 2.0-V devices, contact the Intel Massachusetts Customer Technology  
Center..  
Table 12-3. SA-1100 Power Supply Voltages and Currents with TQFP Package  
SA-1100  
Parameter  
Units  
AA/AB†  
CA/CB†  
DA/DB†  
EA/EB†  
190  
Maximum operating frequency  
133  
160  
220  
MHz  
Maximum run mode power  
(total VDD + VDDX)  
400  
230  
55  
1100  
430  
n/a  
1100  
550  
n/a  
500  
330  
85  
mW  
mW  
mW  
mW  
uA  
Typical run mode power  
(total VDD + VDDX)  
††  
Maximum idle mode power  
(total VDD + VDDX)  
††  
Typical idle mode power  
50  
n/a  
n/a  
65  
(total VDD + VDDX)  
††  
Maximum sleep mode current  
(total VDD + VDDX)  
50  
n/a  
n/a  
50  
††  
Typical sleep mode current  
25  
n/a  
n/a  
30  
uA  
(total VDD + VDDX)  
VDD  
Minimum internal power supply voltage  
Nominal internal power supply voltage  
Maximum internal power supply voltage  
1.42  
1.50  
1.58  
1.90  
2.00  
2.10  
1.90  
2.00  
2.10  
1.42  
1.50  
1.58  
V
V
V
VDDX  
Minimum external power supply voltage  
Nominal external power supply voltage  
Maximum external power supply voltage  
3.00  
3.30  
3.60  
3.00  
3.30  
3.60  
3.00  
3.30  
3.60  
3.00  
3.30  
3.60  
V
V
V
AA, CA, DA and EA refer to TQFP package. AB, CB, DB and EB refer to mBGA package.  
††  
Room temperature specification.  
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AC Parameters  
13  
This chapter defines the ac parameters for the Intel® StrongARM® SA-1100 Microprocessor  
(SA-1100).  
13.1  
Test Conditions  
The AC timing diagrams presented in this chapter assume that the outputs of SA-1100 have been  
loaded with a 50-pF capacitive load on output signals. The output pads of SA-1100 are CMOS  
drivers that exhibit a propagation delay that increases with the increase in load capacitance.  
Table 13-1 lists the output derating figure for each output pad, showing the approximate rate of  
increase of delay with increasing or decreasing load capacitance for a typical process at room  
temperature. For derating figures for 2.0-V devices, contact the Intel Massachusetts Customer  
Technology Center.  
Table 13-1. SA-1100 Output Derating  
Output  
Derating  
Output  
Derating  
Output  
Derating  
Output  
Derating  
Load for  
Output Signal  
Nominal  
Value  
(ns/pF)  
VDD = 1.5 V  
rising edge  
(ns/pF)  
VDD = 1.5 V  
falling edge  
(ns/pF)  
VDD = 2.0 V  
rising edge  
(ns/pF)  
VDD = 2.0 V  
falling edge  
Note  
All outputs  
50 pF  
0.086  
0.077  
0.08  
0.072  
1
NOTE:  
1. Parameter guaranteed by design  
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AC Parameters  
13.2  
Module Considerations  
The edge rates for the SA-1100 processor are such that the lumped load model presented above can  
only be used for etch lengths up to one inch. Over one inch of etch, the signal is a transmission line  
and needs to be modeled as such.  
13.3  
Memory Bus and PCMCIA Signal Timings  
During production test, the SA-1100 is placed in testclock bypass mode by the assertion of the  
TCKBYP pin. This mode (not intended for use by customers) bypasses the 3.686-MHz oscillator  
and the main PLL and sources the processor clock from the TESTCLK pin. During this test mode,  
all clocks on the SA-1100 are synchronous to TESTCLK. In this mode, the basic functionality of  
the chip is tested and the pin timings relative to TESTCLK are measured. The ac parameters are  
measured in this way for each available processor clock speed and supply voltage at which the  
device is offered.  
The ac specifications for the SA-1100 memory and PCMCIA interfaces are provided relative to the  
memory clock. In the testclock bypass mode, memory clock is one-half the frequency of  
TESTCLK. Under normal operation, memory clock is one-half the frequency of the processor  
clock generated by the main PLL.  
Even though this clock is not visible to the user, the required pin timing may be inferred through  
these numbers. Input pins are specified by a required setup and hold to the memory clock. Outputs  
are specified by a propagation delay from the edge of the memory clock where the drive starts to  
the time the pin actually transitions. A 50-pF lumped load is assumed to be on each pin.  
Figure 13-1 shows the memory bus ac timing definitions and Table 13-2 describes the ac timing  
parameters.  
Figure 13-1. Memory Bus AC Timing Definitions  
Memory Clock  
Input hold from memory clock rise  
Input setup to memory clock rise  
Memory Bus In  
(A)  
Input hold from memory clock fall  
Input setup to memory clock fall  
Memory Bus In  
(B)  
Memory clock rise to output driven valid  
Memory clock fall to output driven valid  
Memory Bus Out  
(A)  
Memory Bus Out  
(B)  
A4776-01  
13-2  
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AC Parameters  
13.4  
LCD Controller Signals  
Figure 13-2 describes the LCD timing parameters. The LCD pin timing specifications are  
referenced to the pixel clock (L_PCLK).  
Figure 13-2. LCD AC Timing Definitions  
L_PCLK  
T
pclkdv  
L_LDD[7:0]  
(rise)  
T
pclkdv  
L_LDD[7:0]  
(fall)  
T
pclklv  
L_LCLK  
L_BIAS  
L_FCLK  
T
pclkbv  
T
pclkfv  
A4775-01  
13.5  
MCP Signals  
Figure 13-3 describes the MCP timing parameters. The MCP pin timing specifications are  
referenced to SCLK_C.  
Figure 13-3. MCP AC Timing Definitions  
SCLK_C  
SFRM_C  
TXD_C  
T
sfmv  
T
sfmv  
T
T
rxdh  
rxds  
RXD_C  
A4774-01  
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AC Parameters  
13.6  
Timing Parameters  
Table 13-2 lists the ac timing parameters for the SA-1100 for AA and BA parts. For timing  
parameters for 2.0-V devices, contact the Intel Massachusetts Customer Technology Center.  
Table 13-2. SA-1100 AC Timing Table for AA and BA Parts  
Pin Name  
Memory Bus  
Symbol  
Parameter  
Min Max Unit Note  
Memory clock fall to D<31:0> driven valid  
D<31:0> valid to memory clock rise/fall  
Memory clock rise/fall to data invalid (input  
Tdfov  
Tds  
0
10  
ns  
ns  
ns  
1
D>31:0>  
Tdh  
4
1
5
nPOE, nPWE, nPIOR,  
nPIOW, PSKTSEL,  
nPREG, nPCE<1,2>,  
A<25:0>  
Tmfov  
Memory clock fall to output driven valid  
10  
ns  
nIOIS16 valid to memory clock rise (input  
Memory clock rise to nIOIS16 negated  
Tio16s  
Tio16h  
1
3
ns  
ns  
6
6
nIOIS16  
nWE, nOE  
Tmrov  
Memory clock rise to output driven valid  
10  
ns  
Memory clock rise to output driven valid  
Memory clock rise/fall to nCAS<3:0> driven  
Memory clock rise to nCS<3:0> driven valid  
nRAS<3:0>  
nCAS<3:0>  
nCS<3:0>  
Tmrdv  
Tcasd  
Tcsd  
12  
12  
10  
ns  
ns  
ns  
2
MCP (CODEC) Interface  
SFRM_C  
Tsfrmv  
Trxds  
Trxdh  
Ttxdv  
SCLK_C rise to SFRM_C driven valid  
RXD_C valid to SCLK_C fall (input setup)  
SCLK_C fall to RXD_C invalid (input hold)  
SCLK_C rise to TXD_C valid  
0
21  
22  
ns  
ns  
ns  
ns  
RXD_C  
4
TXD_C  
LCD Controller  
L_LDD<7:0>  
L_LCLK  
Tpclkdv L_PCLK rise/fall to L_LDD<7:0> driven valid  
14  
14  
14  
ns  
ns  
ns  
3
4
4
Tpclklv  
Tpclkfv  
L_PCLK fall to L_LCLK driven valid  
L_PCLK fall to L_LFCLK driven valid  
L_PCLK rise to L_BIAS driven valid  
L_FCLK  
L_BIAS  
Tpclkbv  
14  
ns  
ns  
4
All output signals  
Output pin transition between 0.4V and 2.4V 1.6  
4.5  
NOTES:  
1. These input pins may be sampled on either the rising or falling edge of the memory clock.  
2. These output pins may be driven on either the rising or falling edge of the memory clock.  
3. The LCD data pins can be programmed to be driven on either the rising or falling edge of the pixel clock  
(L_PCLK).  
4. These LCD signals can, at times, transition when L_PCLK is not clocking (between frames). At this time,  
they are clocked with the internal version of the pixel clock before it is driven out onto the L_PCLK pin.  
5. These signals are PCMCIA outputs and are driven by a state machine clocked by BCLK. The user defines  
BCLK by programming the number of processor clocks per BCLK. Two processor clocks make one  
memory clock cycle. To ensure proper operation, the user must adhere to the protocol description.  
6. These signals are PCMCIA inputs and are sampled by a state machine clocked by BCLK. The user defines  
BCLK by programming the number of processor clocks per BCLK. Two processor clocks make one  
memory clock cycle. To ensure proper operation, the user must adhere to the protocol description.  
13-4  
SA-1100 Developer’s Manual  
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AC Parameters  
13.6.1  
Asynchronous Signal Timing Descriptions  
nPWAIT is an input and is received through a synchronizer. As such, it has no setup and hold  
specification. The user must adhere to the protocol definition.  
When the peripheral pins are in GPIO mode, they are read or written under software control. As  
outputs, they are driven valid on the pin approximately 20 ns after they are written by software.  
When inputs, they are received by a synchronizer and must be valid for approximately 20 ns before  
they are able to be recognized by a CPU read.  
nRESET must remain asserted for 150 ms after VDD and VDDX are stable to properly reset the  
SA-1100.  
nRESET_OUT is asserted for all types of reset (hard, watchdog, sleep, and software) and appears  
on the pin asynchronously to all clocks.  
BATT_FAULT and VDD_FAULT are asynchronous inputs and are synchronized to the  
32.768-kHz clock after entering the SA-1100. They must be valid for approximately 60 ms before  
they are recognized by the SA-1100.  
PWR_EN asserts when the SA-1100 enters sleep mode and is driven onto the pin following the  
rising edge of the 32.768-kHz clock. It negates on the same edge as sleep mode is exited.  
GP<27:0> are read and written under software control. In addition, an asynchronous edge detect  
may be performed. When writing a value to these pins, the pin transitions approximately 20 ns after  
the write is performed. When reading these pins, the signal is first synchronized to the internal  
memory clock and must be valid for at least 20 ns before it is visible to a processor read. For edge  
detects, the value on the pin following an edge must be stable for at least 10 ns for the edge to be  
caught by the edge detect circuit.  
UDC+, UDC-, TXD_1, RXD_1, TXD_2, RXD_2, TXD_3, and RXD_3 are asynchronous relative  
to any device outside the SA-1100. The output pins, like all outputs on the SA-1100, have been  
characterized while driving a 50-pF lumped load capacitance.  
SA-1100 Developer’s Manual  
13-5  
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Package and Pinout  
14  
14.1  
Mechanical Data and Packaging Information  
Figure 14-1 shows the SA-1100 208-pin LQFP mechanical drawing. All measurements are in  
millimeters. Table 14-1 lists the SA-1100 pins in numeric order, showing the signal type for each pin.  
Figure 14-1. Quad Flat Pack – 1.4mm (LQFP)  
30.00  
28.00  
View from above  
Pin 208  
Pin 157  
Pin 1  
Pin 156  
SA-1100  
Pin 105  
Pin 52  
Pin 53  
Pin 104  
0.50 typ  
0.60 typ  
0.22  
.
SA-1100 Developer’s Manual  
14-1  
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Package and Pinout  
Table 14-1. SA-1100 Pinout – 208-Pin Quad Flat Pack  
Pin  
Signal  
RXD_C  
Type  
Pin  
Signal  
GP[25]  
Type  
Pin  
Signal  
Type  
Pin  
Signal  
Type  
1
I/O  
I/O  
53  
54  
55  
56  
57  
58  
59  
60  
61  
62  
63  
64  
65  
66  
67  
68  
69  
70  
71  
72  
73  
74  
75  
76  
77  
78  
79  
80  
81  
82  
83  
84  
85  
86  
87  
88  
89  
90  
91  
92  
93  
94  
95  
96  
97  
98  
99  
I/O  
I/O  
I/O  
I/O  
105 nPIOR  
106 nPIOW  
107 VSSX  
108 VDDX2  
109 VSS  
O
O
157 A[11]  
O
O
O
O
2
TXD_C  
VDDX2  
VSSX  
VDD  
GP[24]  
GP[23]  
GP[22]  
VDDX1  
VSSX  
GP[21]  
GP[20]  
GP[19]  
GP[18]  
GP[17]  
GP[16]  
GP[15]  
GP[14]  
VDDX1  
VSSX  
GP[13]  
GP[12]  
GP[11]  
GP[10]  
GP[9]  
158 A[10]  
3
159 A[9]  
4
160 A[8]  
5
161 VSSX  
162 VDDX1  
163 A[7]  
6
VSS  
110 VDD  
7
D[0]  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
111 PSKTSEL  
112 nIOIS16  
113 nPWAIT  
114 nPREG  
115 nPCE2  
116 nPCE1  
117 nWE  
O
I
O
O
O
O
O
O
O
O
8
D[8]  
164 A[6]  
9
D[16]  
D[ 24]  
D[ 1]  
I
165 A[5]  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
28  
29  
30  
31  
32  
33  
34  
35  
36  
37  
38  
39  
40  
41  
42  
43  
44  
45  
46  
47  
48  
49  
50  
51  
52  
O
O
O
O
O
166 A[4]  
167 A[3]  
D[ 9]  
168 A[2]  
D[ 17]  
D[25]  
VDDX2  
VSSX  
D[2]  
169 A[1]  
118 nOE  
170 A[0]  
119 VSSX  
120 VDDX2  
121 nRAS[3]  
122 nRAS[2]  
123 nRAS[1]  
124 nRAS[0]  
125 nCAS[3]  
126 nCAS[2]  
127 nCAS[1]  
128 nCAS[0]  
129 VSSX  
130 VDDX2  
131 VSS  
171 VSSX  
172 VDDX1  
173 UDC-  
174 UDC+  
175 RXD_1  
176 TXD_1  
177 RXD_2  
178 TXD_2  
179 RXD_3  
180 TXD_3  
181 VSSX  
182 VDDX1  
183 VSS  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
O
O
O
O
O
O
O
O
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
D[10]  
D[18]  
D[26]  
D[3]  
D[11]  
D[19]  
D[27]  
VDD  
GP[8]  
GP[7]  
GP[6]  
VDDX1  
VSSX  
VDD  
VSS  
VDDX2  
VSSX  
D[4]  
VSS  
132 VDD  
184 TXTAL  
185 TEXTAL  
186 PEXTAL  
187 PXTAL  
188 VDDP  
189 VSS  
I
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
GP[5]  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
133 nCS[3]  
134 nCS[2]  
135 nCS[1]  
136 nCS[0]  
137 A[25]  
O
O
O
O
O
O
O
O
O
O
I
D[12]  
D[20]  
D[28]  
D[5]  
GP[4]  
GP[3]  
GP[2]  
GP[1]  
D[13]  
D[21]  
D[29]  
VDDX2  
VSSX  
D[6]  
GP[0]  
138 A[24]  
190 VDD  
L_BIAS  
L_PCLK  
VDDX1  
VSSX  
LDD0  
139 A[23]  
191 nRESET  
192 nRESET_OUT  
193 VDDX3  
194 ROMSEL  
195 TCK_BYP  
196 TESTCLK  
197 TMS  
I
140 A[22]  
O
I
141 VSSX  
142 VDDX2  
143 A[21]  
I
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
O
O
O
O
O
O
O
O
I
D[14]  
D[22]  
D[30]  
D[7]  
LDD1  
144 A[20]  
I
LDD2  
145 A[19]  
I
LDD3  
146 A[18]  
198 TCK  
I
LDD4  
147 A[17]  
199 TDI  
I
D[15]  
D[23]  
D[31]  
VDD  
LDD5  
148 A[16]  
200 TDO  
O
I
LDD6  
149 A[15]  
201 nTRST  
202 BATT_FAULT  
203 VSSX  
204 VDDX1  
205 VDD_FAULT  
206 PWR_EN  
207 SFRM_C  
208 SCLK_C  
LDD7  
150 A[14]  
I
VDDX1  
151 VSS  
VSS  
100 VSSX  
101 L_LCLK  
102 L_FCLK  
103 nPOE  
104 nPWE  
152 VDD  
VDDX2  
VSSX  
GP[27]  
GP[26]  
I/O  
I/O  
O
153 VSSX  
154 VDDX2  
155 A[13]  
I
O
O
O
I/O  
I/O  
O
O
O
156 A[12]  
Note: All VDDX1, VDDX2, and VDDX3 pins should be connected directly to the VDDX power plane  
of the system board. VDDP should be connected directly to the VDD plane of the system board.  
14-2  
SA-1100 Developer’s Manual  
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Package and Pinout  
14.2  
Mini-Ball Grid Array – (mBGA)  
Figure 14-2 shows the SA-1100 256 mini-ball grid array (mBGA) mechanical drawing.  
Table 14-2 lists the SA-1100 pins in numeric order, showing the signal type for each pin.  
Figure 14-2. SA-1100 256 Mini-Ball Grid Array Mechanical Drawing  
A6843-01  
SA-1100 Developer’s Manual  
14-3  
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Package and Pinout  
Table 14-2. SA-1100 Pinout – 256-Pin Mini-Ball Grid Array  
BGA  
Pad  
B1  
C2  
J13  
A1  
C1  
D3  
D2  
D1  
F4  
BGA  
Pad  
N6  
P6  
D9  
F7  
R6  
R7  
T6  
P7  
T7  
N8  
P8  
R8  
BGA  
Pad  
G7  
BGA  
Pad  
D7  
D6  
A6  
B6  
C6  
C5  
A5  
B5  
B4  
A4  
H7  
E8  
C4  
A3  
B3  
A2  
H8  
H9  
H10  
H11  
J6  
J7  
J8  
Pin Signal Type  
Pin  
Signal Type  
Pin  
35  
Type  
Pin  
Signal  
Type  
1
2
3
4
5
6
7
8
9
RXD_C I/O  
TXD_C I/O  
65 GP[15]  
66 GP[14]  
67 VDDX1  
68 VSSX  
69 GP[13]  
70 GP[12]  
71 GP[11]  
72 GP[10]  
73 GP[9]  
74 GP[8]  
75 GP[7]  
76 GP[6]  
77 VDDX1  
78 VSSX  
79 VDD  
I/O  
I/O  
129 VSSX  
130 VDDX2  
131 VSS  
O
O
O
O
O
O
O
O
193 VDDX3  
I
I
I
I
I
I
I
O
I
L12 194 ROMSEL  
J16  
J14  
H14 197 TMS  
H13 198 TCK  
H16 199 TDI  
H15 200 TDO  
G14 201 nTRST  
G16 202 BATT_FAULT  
G15 203 VSSX  
F15 204 VDDX1  
VDDX2  
VSSX  
VDD  
VSS  
195 TCK_BYP  
196 TESTCLK  
132 VDD  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
133 nCS[3]  
134 nCS[2]  
135 nCS[1]  
136 nCS[0]  
137 A[25]  
138 A[24]  
139 A[23]  
140 A[22]  
D[0]  
D[8]  
D[16]  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
10 D[ 24]  
11 D[ 1]  
12 D[ 9]  
13 D[ 17]  
14 D[25]  
15 VDDX2  
16 VSSX  
17 D[2]  
18 D[10]  
19 D[18]  
20 D[26]  
21 D[3]  
22 D[11]  
23 D[19]  
24 D[27]  
25 VDD  
26 VSS  
27 VDDX2  
28 VSSX  
29 D[4]  
30 D[12]  
31 D[20]  
32 D[28]  
33 D[5]  
34 D[13]  
35 D[21]  
36 D[29]  
37 VDDX2  
38 VSSX  
39 D[6]  
40 D[14]  
41 D[22]  
42 D[30]  
43 D[7]  
44 D[15]  
45 D[23]  
46 D[31]  
47 VDD  
48 VSS  
49 VDDX2  
50 VSSX  
E3  
E2  
E1  
F3  
I
I
K10 141 VSSX  
G8  
205 VDD_FAULT  
F2  
F8  
T8  
R9  
P9  
T9  
142 VDDX2  
143 A[21]  
144 A[20]  
145 A[19]  
146 A[18]  
L13 206 PWR_EN  
F14 207 SFRM_C  
F13 208 SCLK_C  
O
O
O
K5  
B2  
F1  
G2  
G3  
H4  
G1  
H3  
H2  
J3  
O
O
O
O
O
O
O
O
O
O
O
O
O
O
80 VSS  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
81 GP[5]  
82 GP[4]  
83 GP[3]  
84 GP[2]  
85 GP[1]  
86 GP[0]  
87 L_BIAS  
88 L_PCLK I/O  
89 VDDX1  
90 VSSX  
F16  
E15  
E14  
E16  
D14  
D15  
D16  
C15  
G9  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
VSSX  
N10 147 A[17]  
R10 148 A[16]  
P10 149 A[15]  
T10 150 A[14]  
R11 151 VSS  
P11 152 VDD  
D11 153 VSSX  
J9  
H1  
J2  
J10  
J11  
K6  
K7  
K8  
K9  
L6  
L7  
L8  
F9  
154 VDDX2  
M5  
D13 91 LDD0  
C3  
J1  
K4  
K3  
K2  
K1  
L3  
L2  
L1  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
N12 155 A[13]  
T11 156 A[12]  
R12 157 A[11]  
P12 158 A[10]  
P13 159 A[9]  
T12 160 A[8]  
R13 161 VSSX  
T13 162 VDDX1  
K11 163 A[7]  
F10 164 A[6]  
R14 165 A[5]  
T14 166 A[4]  
R15 167 A[3]  
T15 168 A[2]  
P14 169 A[1]  
P15 170 A[0]  
F11 171 VSSX  
C16  
B16  
C14  
B14  
B15  
A16  
G10  
E6  
A15  
A14  
B13  
C13  
A13  
B12  
C12  
D12  
G11  
E7  
A12  
C11  
B11  
A11  
B10  
D10  
C10  
A10  
H6  
92 LDD1  
93 LDD2  
94 LDD3  
95 LDD4  
96 LDD5  
97 LDD6  
98 LDD7  
99 VDDX1  
100 VSSX  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
VSSX  
VSSX  
L9  
L11  
E9  
O
O
O
O
O
O
O
O
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX1  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
VDDX2  
I/O  
K12 101 L_LCLK  
E10  
E11  
M6  
M7  
M8  
M9  
M10  
M11  
N7  
D4  
M4  
M3  
M2  
M1  
N3  
N2  
P3  
P2  
N1  
P1  
E4  
E5  
R1  
T1  
R2  
P4  
T2  
R3  
D5  
F6  
T3  
R4  
T4  
P5  
R5  
T5  
102 L_FCLK I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
103 nPOE  
104 nPWE  
105 nPIOR  
106 nPIOW  
107 VSSX  
108 VDDX2  
109 VSS  
O
O
O
O
L4  
172 VDDX1  
T16 173 UDC-  
R16 174 UDC+  
P16 175 RXD_1  
N15 176 TXD_1  
N16 177 RXD_2  
N14 178 TXD_2  
M13 179 RXD_3  
M15 180 TXD_3  
M14 181 VSSX  
M16 182 VDDX1  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
I
O
O
I
110 VDD  
111 PSKTSEL O  
N9  
N11  
E12  
E13  
F5  
F12  
G4  
G5  
G12  
G13  
H5  
H12  
J4  
J5  
J12  
M12  
N4  
112 nIOIS16  
113 nPWAIT  
114 nPREG  
115 nPCE2  
116 nPCE1  
117 nWE  
I
I
O
O
O
O
O
51 GP[27] I/O  
52 GP[26] I/O  
53 GP[25] I/O  
54 GP[24] I/O  
55 GP[23] I/O  
56 GP[22] I/O  
118 nOE  
119 VSSX  
L10  
A9  
B9  
C9  
A8  
B8  
C8  
D8  
A7  
G6  
L5  
183 VSS  
184 TXTAL  
120 VDDX2  
121 nRAS[3]  
122 nRAS[2]  
123 nRAS[1]  
124 nRAS[0]  
125 nCAS[3]  
126 nCAS[2]  
127 nCAS[1]  
128 nCAS[0]  
57 VDDX1  
58 VSSX  
O
O
O
O
O
O
O
O
L15 185 TEXTAL  
L14 186 PEXTAL  
L16 187 PXTAL  
K13 188 VDDP  
K15 189 VSS  
K14 190 VDD  
K16 191 nRESET  
J15  
59 GP[21] I/O  
60 GP[20] I/O  
61 GP[19] I/O  
62 GP[18] I/O  
63 GP[17] I/O  
64 GP[16] I/O  
I
B7  
C7  
N5  
N13  
192 nRESET_OUT O  
Note: All VDDX1, VDDX2, and VDDX3 pins should be connected directly to the VDDX power plane  
of the system board. VDDP should be connected directly to the VDD plane of the system board.  
14-4  
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Debug Support  
15  
Due to the integration level of the Intel® StrongARM® SA-1100 Microprocessor (SA-1100), many  
functions are not directly visible on the external pins. Therefore, some basic debug facilities are  
provided that are not present on the Intel® StrongARM® SA-110 Microprocessor (SA-110). These  
facilities are in the form of breakpoints that provide the user with the ability to stop execution after  
seeing a specific reference in either the instruction or data streams. Execution then proceeds to an  
exception routine during which the user may examine the internal state of the machine. The  
instruction and data breakpoint facilities are described in this chapter. The breakpoints are enabled  
through additions to coprocessor 15.  
15.1  
Instruction Breakpoint  
The instruction breakpoint allows the user to stop the processor execution after the execution of an  
instruction at a selected address. This address is programmed into the instruction breakpoint  
address and control register (IBCR). This register is 32 bits wide and contains the address value for  
the breakpoint, and a bit to enable the breakpoint. Bit 0 is the enable bit. When set, this bit enables  
the breakpoint and when cleared, it disables the breakpoint. Bit 1 is reserved and has no effect  
when written. Bits 31..2 are compared against the fetch address to qualify the breakpoint. When the  
breakpoint is enabled, the SA-1100 executes until the instruction at this address is fetched and the  
fetch address equals the program counter (ignoring bits 0 and 1 of the address). At this point, the  
processor takes a prefetch abort exception. The interrupt routine must examine R14 (the saved  
program counter) to determine if the exception was caused by the breakpoint.  
The IBCR is loaded by way of coprocessor 15, register 14. Access to this register is privileged. See  
instruction used to access the IBCR.  
15.2  
Data Breakpoint  
The data breakpoint allows the user to stop the processor execution after a load or store operation  
to a particular address. The data breakpoint address is programmed into the data breakpoint address  
register (DBAR) and is a full 32-bit value (to permit breakpoints on byte accesses).  
For stores, the breakpoint condition may also be programmed to include a particular data pattern as  
well as the reference address. The data value is programmed by way of the data breakpoint value  
register (DBVR) and the data breakpoint mask register (DBMR). The DBVR is a 32-bit register  
containing the value against which the store data is compared. The data value can be further  
qualified through the data breakpoint mask register (DBMR). The DBMR is a 32-bit register  
containing mask information indicating which bits in the store data should be compared against the  
DBMR. A 1 in a particular bit position in the DBMR indicates that bit in the DBVR should be  
compared against the store data to qualify the breakpoint. To cause a breakpoint on a store data  
value, the address breakpoint must also be enabled, otherwise, no breakpoint will occur.  
Breakpoints on loads are permitted only through an address match. Breakpoints on load address,  
store address, and store data are enabled and disabled through the data breakpoint control register  
(DBCR). A single bit is defined for each action. When a breakpoint is taken, the processor takes a  
data abort exception and sets bit 9 in the fault status register (FSR).  
The DBAR, DBVR, and DBMR are loaded by way of coprocessor 15, register 14. Access to this  
register is privileged.  
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Boundary-Scan Test Interface  
16  
The boundary-scan interface conforms to the IEEE Std. 1149.1 – 1990, Standard Test Access Port  
and Boundary-Scan Architecture. (Refer to this standard for an explanation of the terms used in  
this section and for a description of the TAP controller states.) The Intel® StrongARM® SA-1100  
Microprocessor (SA-1100) supports only JTAG continuity testing.  
16.1  
Overview  
The boundary-scan interface provides a means of driving and sampling all the external pins of the  
device irrespective of the core state. This function permits testing of both the devices electrical  
connections to the circuit board and (in conjunction with other devices on the circuit board having  
a similar interface) testing the integrity of the circuit board connections between devices. The  
interface intercepts all external connections within the device, and each such “cell” is then  
connected together to form a serial shift register (the boundary-scan register). The whole interface  
is controlled via five dedicated pins: TDI, TMS, TCK, nTRST, and TDO. Figure 16-1 shows the  
state transitions that occur in the TAP controller. Note that all SA-1100 signals participate in the  
boundary scan. However, in the case of the PWR_EN pin, the contents of the scan latches are not  
placed on the pin. This is to prevent a scan operation from turning off power to the SA-1100.  
Figure 16-1. Test Access Port (TAP) Controller State Transitions  
Test-Logic Reset  
tms=1  
tms=0  
tms=1  
tms=1  
tms=1  
Run-Test/Idle  
Select-DR-Scan  
tms=0  
Select-IR-Scan  
tms=0  
tms=0  
Capture-DR  
tms=0  
Capture-IR  
tms=0  
tms=1  
tms=1  
Shift-DR  
tms=1  
Shift-IR  
tms=1  
tms=0  
tms=0  
tms=1  
Exit1-DR  
tms=0  
Exit1-IR  
tms=0  
tms=1  
tms=0  
Pause-DR  
tms=1  
Pause-IR  
tms=1  
tms=0  
tms=0  
tms=0  
Exit2-DR  
tms=1  
Exit2-IR  
tms=1  
Update-DR  
Update-IR  
tms=1  
tms=0  
tms=1  
tms=0  
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Boundary-Scan Test Interface  
16.2  
Reset  
The boundary-scan interface includes a state-machine controller (the TAP controller). In order to  
force the TAP controller into the correct state after power-up of the device, a reset pulse must be  
applied to the nTRST pin. If the boundary-scan interface is to be used, then nTRST must be driven  
low, and then high again. If the boundary-scan interface is not to be used, then the nTRST pin may  
be tied permanently low. Note that a clock on TCK is not necessary to reset the device.  
The action of reset (either a pulse or a dc level) is as follows:  
System mode is selected (the boundary-scan chain does NOT intercept any of the signals  
passing between the pads and the core).  
IDcode mode is selected. If TCK is pulsed, the contents of the ID register will be clocked out  
of TDO.  
16.3  
Pull-Up Resistors  
The IEEE 1149.1 standard effectively requires that TDI, nTRST, and TMS should have internal  
pull-up resistors. To minimize static current draw, nTRST has an internal pull-down resistor. These  
pins can be left unconnected for normal operation and overdriven to use the JTAG features.  
16.4  
16.5  
Instruction Register  
The instruction register is 5 bits in length. There is no parity bit. The fixed value loaded into the  
instruction register during the CAPTURE-IR controller state is: 00001.  
Public Instructions  
The following public instructions are supported:  
Instruction  
Binary Code  
EXTEST  
SAMPLE/PRELOAD  
CLAMP  
HIGHZ  
IDCODE  
BYPASS  
00000  
00001  
00100  
00101  
00110  
11111  
Private  
00010, 00011, 00111, 01000-01111, 10000-11110  
In the descriptions that follow, TDI and TMS are sampled on the rising edge of TCK, and all output  
transitions on TDO occur as a result of the falling edge of TCK.  
16-2  
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Boundary-Scan Test Interface  
16.5.1  
EXTEST (00000)  
The boundary-scan (BS) register is placed in test mode by the EXTEST instruction. The EXTEST  
instruction connects the BS register between TDI and TDO. When the instruction register is loaded  
with the EXTEST instruction, all the boundary-scan cells are placed in their test mode of operation.  
In the CAPTURE-DR state, inputs from the system pins and outputs from the boundary-scan  
output cells to the system pins are captured by the boundary-scan cells. In the SHIFT-DR state, the  
previously captured test data is shifted out of the BS register via the TDO pin, while new test data  
is shifted in via the TDI pin to the BS register parallel input latch. In the UPDATE-DR state, the  
new test data is transferred into the BS register parallel output latch. Note that this data is applied  
immediately to the system logic and system pins.  
16.5.2  
SAMPLE/PRELOAD (00001)  
The BS register is placed in normal (system) mode by the SAMPLE/PRELOAD instruction. The  
SAMPLE/PRELOAD instruction connects the BS register between TDI and TDO. When the  
instruction register is loaded with the SAMPLE/PRELOAD instruction, all the boundary-scan cells  
are placed in their normal system mode of operation.  
In the CAPTURE-DR state, a snapshot of the signals at the boundary-scan cells is taken on the  
rising edge of TCK. Normal system operation is unaffected. In the SHIFT-DR state, the sampled  
test data is shifted out of the BS register via the TDO pin, while new data is shifted in via the TDI  
pin to preload the BS register parallel input latch. In the UPDATE-DR state, the preloaded data is  
transferred into the BS register parallel output latch. Note that this data is not applied to the system  
logic or system pins while the SAMPLE/PRELOAD instruction is active. This instruction should  
be used to preload the boundary-scan register with known data prior to selecting EXTEST  
instructions.  
16.5.3  
CLAMP (00100)  
The CLAMP instruction connects a 1-bit shift register (the BYPASS register) between TDI and TDO.  
When the CLAMP instruction is loaded into the instruction register, the state of all output signals is  
defined by the values previously loaded into the boundary-scan register. A guarding pattern  
(specified for this device at the end of this section) should be preloaded into the boundary-scan  
register using the SAMPLE/PRELOAD instruction prior to selecting the CLAMP instruction.  
In the CAPTURE-DR state, a logic 0 is captured by the bypass register. In the SHIFT-DR state, test  
data is shifted into the bypass register via TDI and out via TDO after a delay of one TCK cycle.  
Note that the first bit shifted out will be a zero. The bypass register is not affected in the  
UPDATE-DR state.  
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Boundary-Scan Test Interface  
16.5.4  
HIGHZ (00101)  
The HIGHZ instruction connects a 1-bit shift register (the BYPASS register) between TDI and  
TDO. When the HIGHZ instruction is loaded into the instruction register, all outputs are placed in  
an inactive drive state.  
In the CAPTURE-DR state, a logic 0 is captured by the bypass register. In the SHIFT-DR state, test  
data is shifted into the bypass register via TDI and out via TDO after a delay of one TCK cycle.  
Note that the first bit shifted out will be a zero. The bypass register is not affected in the  
UPDATE-DR state.  
16.5.5  
IDCODE (00110)  
The IDCODE instruction connects the device identification register (or ID register) between TDI  
and TDO. The ID register is a 32-bit register that allows the manufacturer, part number and version  
of a component to be determined through the TAP. When the instruction register is loaded with the  
IDCODE instruction, all the boundary-scan cells are placed in their normal (system) mode of  
operation.  
In the CAPTURE-DR state, the device identification code (specified at the end of this section) is  
captured by the ID register. In the SHIFT-DR state, the previously captured device identification  
code is shifted out of the ID register via the TDO pin, while data is shifted in via the TDI pin into  
the ID register. In the UPDATE-DR state, the ID register is unaffected.  
16.5.6  
BYPASS (11111)  
The BYPASS instruction connects a 1-bit shift register (the BYPASS register) between TDI and  
TDO. When the BYPASS instruction is loaded into the instruction register, all the boundary-scan  
cells are placed in their normal (system) mode of operation. This instruction has no effect on the  
system pins.  
In the CAPTURE-DR state, a logic 0 is captured by the bypass register. In the SHIFT-DR state, test  
data is shifted into the bypass register via TDI and out via TDO after a delay of one TCK cycle.  
Note that the first bit shifted out will be a zero. The bypass register is not affected in the  
UPDATE-DR state.  
16-4  
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Boundary-Scan Test Interface  
16.6  
Test Data Registers  
Figure 16-2 illustrates the structure of the boundary-scan logic.  
Figure 16-2. Boundary-Scan Block Diagram  
BSINENCELL  
®
BSINCELL  
I/O  
Intel  
®
StrongARM  
SA-1100  
Cell  
BSINCELL  
BSOUTCELL  
Core Logic  
BSOUTNENCELL  
BSOUTCELL  
Device ID Register  
Bypass Register  
TDO  
Instruction Decoder  
Instruction Register  
TDI  
TMS  
TCK  
TAP  
Controller  
nTDOEN  
nTRST  
* StrongARM is a registered trademark of ARM Limited.  
A6839-01  
16.6.1  
Bypass Register  
Purpose: This is a single-bit register that can be selected as the path between TDI and TDO to  
allow the device to be bypassed during boundary-scan testing.  
Length: 1 bit  
Operating Mode: When the BYPASS instruction is the current instruction in the instruction  
register, serial data is transferred from TDI to TDO in the SHIFT-DR state with a delay of one TCK  
cycle.  
There is no parallel output from the bypass register.  
A logic 0 is loaded from the parallel input of the bypass register in the CAPTURE-DR state.  
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Boundary-Scan Test Interface  
16.6.2  
SA-1100 Device Identification (ID) Code Register  
Purpose: This register is used to read the 32-bit device identification code. No programmable  
supplementary identification code is provided.  
Length: 32 bits  
Operating Mode: When the IDCODE instruction is current, the ID register is selected as the serial  
path between TDI and TDO.  
The format of the ID register is as follows:  
31  
28 27  
12 11  
0
Version  
Part Number  
JEDEC Code  
The high-order 4 bits of the ID register contains the version number of the silicon and changes with  
each new revision.  
There is no parallel output from the ID register.  
The 32-bit device identification code is loaded into the ID register from its parallel inputs during  
the CAPTURE-DR state.  
16.6.3  
SA-1100 Boundary-Scan (BS) Register  
Purpose: The BS register consists of a serially connected set of cells around the periphery of the  
device, at the interface between the core logic and the system input/output pads. This register can  
be used to isolate the pins from the core logic and then drive or monitor the system pins.  
Operating Modes: The BS register is selected as the register to be connected between TDI and  
TDO only during the SAMPLE/PRELOAD and EXTEST instructions. Values in the BS register  
are used, but are not changed, during the CLAMP instruction.  
In the normal (system) mode of operation, straight-through connections between the core logic and  
pins are maintained, and normal system operation is unaffected.  
In TEST mode (when EXTEST is the currently selected instruction), values can be applied to the  
output pins independently of the actual values on the input pins and core logic outputs. On the  
SA-1100, all of the boundary-scan cells include update registers; thus, all of the pins can be  
controlled in the above manner. An additional boundary-scan cell is interposed in the scan chain to  
control the enabling of the data bus.  
The EXTEST guard values should be clocked into the boundary-scan register (using the  
SAMPLE/PRELOAD instruction) before the EXTEST instruction is selected, to ensure that known  
data is applied to the core logic during the test. These guard values should also be used when new  
EXTEST vectors are clocked into the boundary-scan register.  
The values stored in the BS register after power-up are not defined. Similarly, the values previously  
clocked into the BS register are not guaranteed to be maintained across a boundary-scan reset  
(from forcing nTRST low or entering the Test Logic Reset state).  
Figure 16-3, Figure 16-4, and Figure 16-5 show the typical timing for the BS register.  
16-6  
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Boundary-Scan Test Interface  
16.7  
Boundary-Scan Interface Signals  
Figure 16-3. Boundary-Scan General Timing  
Tbsch  
Tbscl  
tck  
tms, tdi  
Tbsis  
Tbsih  
tdo  
Tbsoh  
Tbsod  
Data In  
Tbsss  
Tbssh  
Data Out  
Tbsdh  
Tbsdd  
A4772-01  
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Boundary-Scan Test Interface  
Figure 16-4. Boundary-Scan Tristate Timing  
tck  
tdo  
Tbsoe  
Tbsde  
Tbsoz  
Tbsdz  
Data Out  
A4773-01  
Figure 16-5. Boundary-Scan Reset Timing  
ntrst  
tms  
Tbsr  
Tbsrs Tbsrh  
A4771-01  
16-8  
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Boundary-Scan Test Interface  
Table 16-1 shows the SA-1100 boundary-scan interface timing specifications.  
Table 16-1. SA-1100 Boundary-Scan Interface Timing  
Symbol  
Tbscl  
Parameter  
Minimum  
Typical  
Maximum  
Units  
Notes  
TCK low period  
50  
50  
10  
10  
5
ns  
ns  
ns  
ns  
ns  
ns  
ns  
8
8
1
1
4
Tbsch  
Tbsis  
TCK high period  
TDI,TMS setup to [TCr]  
TDI,TMS hold from [TCr]  
TDO hold time  
Tbsih  
Tbsoh  
Tbsod  
Tbsss  
TCf to TDO valid  
40  
I/O signal setup to [TCr]  
5
I/O signal hold from  
[TCr]  
Tbssh  
20  
ns  
4
Tbsdh  
Tbsdd  
Tbsoe  
Tbsoz  
Tbsde  
Tbsdz  
Tbsr  
Data output hold time  
TCf to data output valid  
TDO enable time  
5
40  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
5
5
1,2  
1,3  
5,6  
5,7  
8
TDO disable time  
40  
Data output enable time  
Data output disable time  
Reset period  
5
40  
30  
10  
10  
Tbsrs  
Tbsrh  
NOTES:  
TMS setup to [TRr]  
TMS hold from [TRr]  
8
1. Assumes a 25-pF load on TDO. Output timing derates at 0.072 ns/pF of extra load applied.  
2. TDO enable time applies when the TAP controller enters the Shift-DR or Shift-IR states.  
3. TDO disable time applies when the TAP controller leaves the Shift-DR or Shift-IR states.  
4. For correct data latching, the I/O signals (from the core and the pads) must be set up and held with respect  
to the rising edge of TCK in the CAPTURE-DR state of the SAMPLE/PRELOAD and EXTEST instructions.  
5. Assumes that the data outputs are loaded with the ac test loads.  
6. Data output enable time applies when the boundary-scan logic is used to enable the output drivers.  
7. Data output disable time applies when the boundary scan is used to disable the output drivers.  
8. TCK may be stopped indefinitely in either the low or high phase.  
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Register Summary  
A
This appendix describes all of the Intel® StrongARM® SA-1100 Microprocessor (SA-1100)  
internal registers.  
Physical Address  
Symbol  
Register Name  
GPIO Registers  
0h 9004 0000  
0h 9004 0004  
0h 9004 0008  
0h 9004 000C  
0h 9004 0010  
0h 9004 0014  
0h 9004 0018  
0h 9004 001C  
Interrupt Controller Registers  
0h 9005 0000  
0h 9005 0004  
0h 9005 0008  
0h 9005 0010  
0h 9005 0020  
0h 9005 000c  
GPLR  
GPDR  
GPSR  
GPCR  
GRER  
GFER  
GEDR  
GAFR  
GPIO pin level register.  
GPIO pin direction register.  
GPIO pin output set register.  
GPIO pin output clear register.  
GPIO rising-edge register.  
GPIO falling-edge register.  
GPIO edge detect status register.  
GPIO alternate function register.  
ICIP  
Interrupt controller irq pending register.  
Interrupt controller mask register.  
ICMR  
ICLR  
ICFP  
ICPR  
ICPR  
Interrupt controller FIQ level register.  
Interrupt controller FIQ pending register.  
Interrupt controller pending register.  
Interrupt controller control register.  
Real-Time Clock Registers  
0h 9001 0004  
0h 9001 0000  
0h 9001 0010  
0h 9001 0008  
OS Timer Registers  
0h 9000 0000  
0h 9000 0004  
0h 9000 0008  
0h 9000 000C  
0h 9000 0010  
0h 9000 0014  
0h 9000 0018  
0h 9000 001C  
RCNR  
RTAR  
RTSR  
RTTR  
Real-time clock count register.  
Real-time clock alarm register.  
Real-time clock status register.  
Real-time clock trim register.  
OSMR[0]  
OSMR[1]  
OSMR[2]  
OSMR[3]  
OSCR  
OS timer match registers[3:0].  
OS timer counter register.  
OSSR  
OS timer status register.  
OWER  
OS timer watchdog enable register.  
OS timer interrupt enable register.  
OIER  
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Register Summary  
Physical Address  
Symbol  
Register Name  
Power Manager Registers  
0h 9002 0000  
PMCR  
PSSR  
PSPR  
PWER  
PCFR  
PPCR  
PGSR  
POSR  
Power manager control register.  
0h 9002 0004  
Power manager sleep status register.  
Power manager scratchpad register.  
Power manager wakeup enable register.  
Power manager configuration register.  
Power manager PLL configuration register.  
Power manager GPIO sleep state register.  
Power manager oscillator status register.  
0h 9002 0008  
0h 9002 000C  
0h 9002 0010  
0h 9002 0014  
0h 9002 0018  
0h 9002 001C  
Reset Controller Registers  
0h 9003 0000  
RSRR  
RCSR  
TUCR  
Reset controller software reset register.  
Reset controller status register.  
Reserved for test.  
0h 9003 0004  
0h 9003 0008  
Memory Controller Registers  
0xA000 0000  
MDCNFG  
MDCAS0  
MDCAS1  
MDCAS2  
MSC0  
DRAM configuration register.  
0xA000 0004  
DRAM CAS waveform shift register 0.  
DRAM CAS waveform shift register 1.  
DRAM CAS waveform shift register 2.  
Static memory control register 0.  
Static memory control register 1.  
Expansion bus configuration register.  
0xA000 0008  
0xA000 000C  
0xA000 0010  
0xA000 0014  
MSC1  
0xA000 0018  
MECR  
DMA Controller Registers  
0h B000 0000  
0h B000 0004  
0h B000 0008  
0h B000 000C  
0h B000 0010  
0h B000 0014  
0h B000 0018  
0h B000 001C  
0h B000 0020  
0h B000 0024  
0h B000 0028  
0h B000 002C  
0h B000 0030  
0h B000 0034  
0h B000 0038  
0h B000 003C  
0h B000 0040  
DDAR0  
DCSR0  
DMA device address register.  
DMA control/status register 0 – write ones to set.  
Write ones to clear.  
Read only.  
DBSA0  
DBTA0  
DBSB0  
DBTB0  
DDAR1  
DMA buffer A start address 0.  
DMA buffer A transfer count 0.  
DMA buffer B start address 0.  
DMA buffer B transfer count 0.  
DMA device address register 1.  
DMA control/status register 1 – write ones to set.  
Write ones to clear.  
DCSR1  
Read only.  
DBSA1  
DBTA1  
DBSB1  
DBTB1  
DDAR2  
DMA buffer A start address 1.  
DMA buffer A transfer count 1.  
DMA buffer B start address 1.  
DMA buffer B transfer count 1.  
DMA device address register 2.  
A-2  
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Register Summary  
Physical Address  
Symbol  
Register Name  
0h B000 0044  
0h B000 0048  
0h B000 004C  
0h B000 0050  
0h B000 0054  
0h B000 0058  
0h B000 005C  
0h B000 0060  
0h B000 0064  
0h B000 0068  
0h B000 006C  
0h B000 0070  
0h B000 0074  
0h B000 0078  
0h B000 007C  
0h B000 0080  
0h B000 0084  
0h B000 0088  
0h B000 008C  
0h B000 0090  
0h B000 0094  
0h B000 0098  
0h B000 009C  
0h B000 00A0  
0h B000 00A4  
0h B000 00A8  
0h B000 00AC  
0h B000 00B0  
0h B000 00B4  
0h B000 00B8  
0h B000 00BC  
DMA control/status register 2 – write ones to set.  
Write ones to clear.  
DCSR2  
Read only.  
DBSA2  
DBTA2  
DBSB2  
DBTB2  
DDAR3  
DMA buffer A start address 2.  
DMA buffer A transfer count 2.  
DMA buffer B start address 2.  
DMA buffer B transfer count 2.  
DMA device address register 3.  
DMA control/status register 3 – write ones to set.  
Write ones to clear.  
DCSR3  
Read only.  
DBSA3  
DBTA3  
DBSB3  
DBTB3  
DDAR4  
DMA buffer A start address 3.  
DMA buffer A transfer count 3.  
DMA buffer B start address 3.  
DMA buffer B transfer count 3.  
DMA device address register 4.  
DMA control/status register 4 – write ones to set.  
Write ones to clear.  
DCSR4  
Read only.  
DBSA4  
DBTA4  
DBSB4  
DBTB4  
DDAR5  
DMA buffer A start address 4.  
DMA buffer A transfer count 4.  
DMA buffer B start address 4.  
DMA buffer B transfer count 4.  
DMA device address register 5.  
DMA control/status register 5 – write ones to set.  
Write ones to clear.  
DCSR5  
Read only.  
DBSA5  
DBTA5  
DBSB5  
DBTB5  
DMA buffer A start address 5.  
DMA buffer A transfer count 5.  
DMA buffer B start address 5.  
DMA buffer B transfer count 5.  
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Register Summary  
Physical Address  
Symbol  
Register Name  
LCD Controller Registers  
0hB010 0000  
LCCR0  
LCSR  
LCD controller control register 0.  
LCD controller status register.  
Reserved.  
0hB010 0004  
0hB010 0008 – 0hB010 000C  
0hB010 0010  
DBAR1  
DCAR1  
DBAR2  
DCAR2  
LCCR1  
LCCR2  
LCCR3  
DMA channel 1 base address register.  
DMA channel 1 current address register.  
DMA channel 2 base address register.  
DMA channel 2 current address register.  
LCD controller control register 1.  
LCD controller control register 2.  
LCD controller control register 3.  
Reserved.  
0hB010 0014  
0hB010 0018  
0hB010 001C  
0hB010 0020  
0hB010 0024  
0hB010 0028  
0hB010 002C – 0hB010 FFFF  
UDC Registers (Serial Port 0)  
0h8000 0000  
UDCCR  
UDCAR  
UCDOMP  
UDCIMP  
UDCCS0  
UDCCS1  
UDCCS2  
UDCD0  
UDCWC  
UDC control register.  
0h8000 0004  
UDC address register.  
0h8000 0008  
UDC OUT max packet register.  
UDC IN max packet register.  
UDC endpoint 0 control/status register.  
UDC endpoint 1 (out) control/status register.  
UDC endpoint 2 (in) control/status register.  
UDC endpoint 0 data register.  
UDC endpoint 0 write count register.  
Reserved.  
0h8000 000C  
0h8000 0010  
0h8000 0014  
0h8000 0018  
0h8000 001C  
0h8000 0020  
0h8000 0024  
0h8000 0028  
UDCDR  
UDC transmit/receive data register (FIFOs).  
Reserved.  
0h8000 002C  
0h8000 0030  
UDCSR  
UDC status/interrupt register.  
UART Registers (Serial Port 1)  
0h 8001 0000  
UTCR0  
UTCR1  
UTCR2  
UTCR3  
UART control register 0.  
UART control register 1.  
UART control register 2.  
UART control register 3.  
Reserved.  
0h 8001 0004  
0h 8001 0008  
0h 8001 000C  
0h 8001 0010  
0h 8001 0014  
UTDR  
UART data register.  
Reserved.  
0h 8001 0018  
0h 8001 001C  
UTSR0  
UTSR1  
UART status register 0.  
UART status register 1.  
Reserved.  
0h 8001 0020  
0h 8001 0024 – 0h 8001 FFFF  
A-4  
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Register Summary  
Physical Address  
Symbol  
Register Name  
SDLC Registers (Serial Port 1)  
0h 8002 0060  
SDCR0  
SDCR1  
SDCR2  
SDCR3  
SDCR4  
SDLC control register 0.  
SDLC control register 1.  
SDLC control register 2.  
SDLC control register 3.  
SDLC control register 4.  
Reserved.  
0h 8002 0064  
0h 8002 0068  
0h 8002 006C  
0h 8002 0070  
0h 8002 0074  
0h 8002 0078  
SDDR  
SDLC data register.  
Reserved.  
0h 8002 007C  
0h 8002 0080  
SDSR0  
SDSR1  
SDLC status register 0.  
SDLC status register 1.  
Reserved.  
0h 8002 0084  
0h 8002 0088 – 0h 8002 FFFF  
ICP – UART Registers (Serial Port 2)  
0h 8003 0000  
UTCR0  
UART control register 0.  
UART control register 1.  
UART control register 2.  
UART control register 3.  
UART control register 4.  
UART data register.  
Reserved.  
0h 8003 0004  
UTCR1  
UTCR2  
UTCR3  
UTCR4  
UTDR  
0h 8031 0008  
0h 8003 000C  
0h 8003 0010  
0h 8003 0014  
0h 8003 0018  
0h 8003 001C  
0h 8003 0020  
UTSR0  
UTSR1  
UART status register 0.  
UART status register 1.  
Reserved.  
0h 8003 0024 – 0h 8003 FFFF  
ICP – HSSP Registers (Serial Port 2)  
0h 8004 0060  
HSCR0  
HSSP control register 0.  
HSSP control register 1.  
Reserved.  
0h 8004 0064  
HSCR1  
0h 8004 0068  
0h 8004 006C  
HSDR  
HSSP data register.  
Reserved.  
0h 8004 0070  
0h 8004 0074  
HSSR0  
HSSR1  
HSSP status register 0.  
HSSP status register 1.  
Reserved.  
0h 8004 0078  
0h 8004 007C – 0h 8004 FFFF  
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Register Summary  
Physical Address  
Symbol  
Register Name  
UART Registers (Serial Port 3)  
0h 8005 0000  
UTCR0  
UTCR1  
UTCR2  
UTCR3  
UART control register 0.  
UART control register 1.  
UART control register 2.  
UART control register 3.  
Reserved.  
0h 8005 0004  
0h 8005 0008  
0h 8005 000C  
0h 8005 0010  
0h 8005 0014  
UTDR  
UART data register.  
Reserved.  
0h 8005 0018  
0h 8005 001C  
UTSR0  
UTSR1  
UART status register 0.  
UART status register 1.  
Reserved.  
0h 8005 0020  
0h 8005 0024 – 0h 8005 FFFF  
MCP Registers (Serial Port 4)  
0h 8006 0000  
MCCR0  
MCP control register 0.  
Reserved.  
0h 8006 0004  
0h 8006 0008  
MCDR0  
MCDR1  
MCDR2  
MCP data register 0.  
MCP data register 1.  
MCP data register 2.  
Reserved.  
0h 8006 000C  
0h 8006 0010  
0h 8006 0014  
0h 8006 0018  
MCSR  
MCP status register.  
Reserved.  
0h 8006 001C – 0h 8006 005C  
SSP Registers (Serial Port 4)  
0h 8007 0060  
SSCR0  
SSCR1  
SSP control register 0.  
SSP control register 1.  
Reserved.  
0h 8007 0064  
0h 8007 0068  
0h 8007 006C  
SSDR  
SSP data register.  
Reserved.  
0h 8007 0070  
0h 8007 0074  
SSSR  
SSP status register.  
Reserved.  
0h 8007 0078 – 0h 8007 FFFF  
PPC Registers  
0h 9006 0000  
PPDR  
PPSR  
PPAR  
PSDR  
PPFR  
MCCR1  
PPC pin direction register.  
PPC pin state register.  
PPC pin assignment register.  
PPC sleep mode direction register.  
PPC pin flag register.  
0h 9006 0004  
0h 9006 0008  
0h 9006 000C  
0h 9006 0010  
0h 9006 0030  
MCP control register 1.  
Reserved.  
0h 9006 0034 – 0h 9006 FFFF  
A-6  
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3.6864–MHz Oscillator Specifications B  
A 3.6864-MHz crystal oscillator is integrated on the Intel® StrongARM® SA-1100 Microprocessor  
(SA-1100) for use as a reference frequency for the PLLs that generate the internal clocks to the  
processor. The phase noise of this reference frequency should be minimized because it could be  
amplified by the PLLs, resulting in PLL output frequency jitter. For this application, the long-term  
stability and the temperature effect on the frequency are not important because they affect the  
frequency by less than 1%. The oscillator circuit is designed to work across a range of crystal  
parameters so that the system designer can choose from several 3.6864-MHz crystals available on  
the market. In normal operation, the pins of the crystal, Q1 and Q2, are connected to the SA-1100  
pins, PXTAL and PEXTAL. Note that a 3.5795-MHz crystal can also be used, but in order to meet  
the frequency specifications of several of the integrated I/O ports, a 3.6864-MHz crystal is  
required.  
In some applications, it may be desirable to provide the 3.6864-MHz reference from an external  
signal source. This option is supported by the SA-1100. See Chapter 8, “Clocks”.  
B.1  
Specifications  
This section includes specifications for the oscillator circuit and the quartz crystal.  
B.1.1  
System Specifications  
This section includes the specifications of the oscillator circuit. It assumes that the crystal used  
meets the specifications given in the following sections.  
Temperature Range  
This is the junction temperature range for the oscillator circuit on the SA-1100. The crystal itself  
may be at the ambient temperature; the oscillator circuit integrated on the SA-1100 is most likely  
operating at a higher temperature that is dependent on the activity of the SA-1100.  
Current Consumption  
Because this oscillator might run during the sleep mode of the processor, the power consumption is  
critical. The specified current consumption is for the oscillator only. The power associated with the  
oscillator output buffer is not included because this buffer is powered down in sleep.  
Startup Time  
This specification depends on the crystal characteristics and the layout of the printed circuit board  
(PCB). The value given assumes that the crystal and board layout conform to the values given in  
the remainder of this document. The critical parameters in the crystal specification are the shunt  
capacitance (Co) and the motional resistance (Rm), which must be no greater than the maximums  
specified. The critical parameters in the PCB layout are the parasitic capacitances between PXTAL  
and PEXTAL, and between either of these nodes and VSS. Note that in some applications, such as  
a system that includes a socketed SA-1100, it may be difficult to meet the parasitic capacitances  
specified. While the 3.6864-MHz oscillator will start with parasitic capacitances, which are  
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3.6864–MHz Oscillator Specifications  
approximately twice the values given, the startup time in this situation will be about double the  
specified startup time and the current consumption will increase. Capacitances larger than twice the  
specified values may prevent the oscillator from starting.  
B.1.1.1.  
B.1.1.2.  
Parasitic Capacitance Off-chip Between PXTAL and PEXTAL  
The parasitic capacitance off-chip between PXTAL and PEXTAL is the board capacitance  
between the PXTAL and PEXTAL pins.  
Parasitic Capacitance Off-chip Between PXTAL or PEXTAL and VSS  
The parasitic capacitance off-chip between PXTAL or PEXTAL and VSS is the parasitic board  
capacitance between the PXTAL or PEXTAL pins and the VSS wire surrounding the crystal  
connections.  
B.1.1.3.  
B.1.1.4.  
Parasitic Resistance Between PXTAL and PEXTAL  
The parasitic resistance between PXTAL and PEXTAL is the parasitic resistance between the  
PXTAL and PEXTAL pins due to moisture and other effects.  
Parasitic Resistance Between PXTAL or PEXTAL and VSS  
The parasitic resistance between PXTAL or PEXTAL and VSS is the parasitic resistance between  
the PXTAL or PEXTAL pins to VSS due to moisture and other effects.  
The following table describes the system specifications of the oscillator circuit.  
Specification  
Minimum  
Typical  
Maximum  
Unit  
o
Temperature range  
Supply voltage  
0
100  
3.6  
0.3  
40  
C
3
3.3  
V
Ripple voltage on the supply  
Current consumption  
Startup time  
V
15  
15  
µA  
ms  
150  
Parasitic capacitance off-chip  
between PXTAL and PEXTAL  
pF  
pF  
1
2
Parasitic capacitance off-chip  
between PXTAL or PEXTAL and  
VSS  
Parasitic resistance between  
PXTAL or PEXTAL to VSS  
1
1
MΩ  
MΩ  
Parasitic resistance between  
PXTAL and PEXTAL  
B-2  
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3.6864–MHz Oscillator Specifications  
B.1.2  
Quartz Crystal Specification  
The following specifications for the quartz crystal are shown in the figure and table below.  
Resonance frequency (fs):  
Motional capacitance (Cm):  
Resonance frequency of the crystal.  
Equivalent serial capacitance in the crystal  
model.  
Motional inductance (Lm):  
Motional resistance (Rm):  
Not generally given in supplier specification.  
Equivalent serial resistance in the crystal  
model. Some crystal providers refer to this  
resistance as the Equivalent Series  
Resistance (ESR) or simply Series  
Resistance.  
Shunt capacitance (Co):  
Load capacitance (CL):  
Parasitic capacitance between Q1 and Q2.  
Needed load capacitance viewed by the  
crystal to oscillate at fs.  
Drive level:  
Aging:  
Power dissipated in the equivalent serial  
resistance (Rm).  
Resonance frequency shift due to aging.  
Co  
Q1  
Q2  
Cm  
Lm  
Rm  
Specification  
Minimum  
Typical  
Maximum  
Unit  
Resonance frequency (fs)  
Motional resistance (Rm)  
Shunt capacitance (Co)  
Drive level  
3.5795  
40  
3.6864  
180  
300  
7
MHz  
W
pF  
10  
µW  
Crystal type  
AT cut crystal  
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32.768–kHz Oscillator Specifications C  
A 32.768-kHz crystal oscillator is integrated on the Intel® StrongARM® SA-1100 Microprocessor  
(SA-1100) for use as a time base for the real-time clock (RTC). The output frequency of the crystal  
oscillator is divided by 32768 (215) to deliver a 1-Hz signal to the RTC. A digital tuning circuit is  
included on the SA-1100 in order to calibrate the 1-Hz output for each crystal and circuit based on a  
set of values stored in an external EEPROM. The oscillator circuit is designed to work across a range  
of crystal parameters so that the system designer can choose from several 32.768-kHz crystals  
available on the market. In normal operation, the pins of the crystal, Q1 and Q2, are connected to the  
SA-1100 pins, TXTAL and TEXTAL.  
In some applications, it may be desirable to provide the 32.768-kHz reference from an external  
signal source. This option is supported by the SA-1100. See the Chapter 8, “Clocks”.  
C.1  
Specifications  
This section includes specifications for the oscillator circuit and the quartz crystal.  
C.1.1  
System Specifications  
This section includes the specifications of the oscillator circuit. It assumes that the crystal used  
meets the specifications given in the following sections.  
C.1.1.1.  
C.1.1.2.  
C.1.1.3.  
Temperature Range  
This is the junction temperature range for the oscillator circuit on the SA-1100. The crystal itself  
may be at the ambient temperature; the oscillator circuit integrated on the SA-1100 is most likely  
operating at a higher temperature that is dependent on the activity of the SA-1100.  
Current Consumption  
Because this oscillator runs during the sleep mode of the processor, the power consumption is  
critical. The specified current consumption is for the oscillator and its output buffer only. The  
power of the tuning circuit and RTC is not included in the value specified.  
Startup Time  
This specification depends on the crystal characteristics and the layout of the printed circuit board  
(PCB). The value given assumes that the crystal and board layout conform to the values given in  
the remainder of this document. The critical parameters in the crystal specification are the shunt  
capacitance (Co) and the motional resistance (Rm), which must be no greater than the maximums  
specified. The critical parameters in the PCB layout are the parasitic capacitances between TXTAL  
and TEXTAL, and between either of these nodes and VSS. Note that in some applications, such as  
a system that includes a socketed SA-1100, it may be difficult to meet the parasitic capacitances  
specified. While the 32.768-kHz oscillator will start with parasitic capacitances which are  
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32.768–kHz Oscillator Specifications  
approximately twice the values given; the startup time in this situation will be about double the  
specified startup time and the current consumption will increase. Capacitances larger than twice the  
specified values may prevent the oscillator from starting.  
C.1.1.4.  
Frequency Shift Due to Temperature Effect on the Circuit  
The frequency shift due to temperature effect on the circuit is the influence of the oscillator circuit  
on the frequency of oscillation due to temperature effect. The appropriate temperature range is the  
junction temperature on the SA-1100, not the ambient temperature. Note that this specification  
does not include either the temperature effects on the quartz or the aging of the crystal. It includes  
the temperature effect of the circuit only. The frequency shift of the crystal itself due to temperature  
may be significantly larger than that of the oscillator circuit. However, for a long-term stability  
calculation, it may be appropriate to consider the average temperature of the crystal rather than the  
extreme values of temperature.  
C.1.1.5.  
C.1.1.6.  
Parasitic Capacitance Off-chip Between TXTAL and TEXTAL  
The parasitic capacitance off-chip between TXTAL and TEXTAL is the board capacitance between  
the TXTAL and TEXTAL pins.  
Parasitic Capacitance Off-chip Between TXTAL or TEXTAL and VSS  
The parasitic capacitance off-chip between TXTAL or TEXTAL and VSS is the parasitic board  
capacitance between the TXTAL or TEXTAL pins and the VSS wire surrounding the crystal  
connections.  
C.1.1.7.  
C.1.1.8.  
Parasitic Resistance Between TXTAL and TEXTAL  
The parasitic resistance between TXTAL and TEXTAL is the parasitic resistance between the  
TXTAL and TEXTAL pins due to moisture and other effects.  
Parasitic Resistance Between TXTAL or TEXTAL and VSS  
The parasitic resistance between TXTAL or TEXTAL and VSS is the parasitic resistance between  
the TXTAL or TEXTAL pins to VSS due to moisture and other effects.  
The following table describes the specifications of the oscillator circuit.  
Specification  
Minimum Typical  
Maximum Unit  
o
Temperature range  
0
100  
3.6  
0.3  
2
C
Supply voltage  
3
3.3  
1
V
Ripple voltage on the supply  
Current consumption  
V
µA  
s
Startup time  
2
Frequency shift due to temperature effect on the circuit  
+/-3  
ppm  
Parasitic capacitance off-chip  
between TXTAL and TEXTAL  
1
pF  
C-2  
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32.768–kHz Oscillator Specifications  
Parasitic capacitance off-chip  
between TXTAL or TEXTAL and VSS  
2
pF  
Parasitic resistance between  
TXTAL or TEXTAL to VSS  
10  
MΩ  
Parasitic resistance between  
TXTAL and TEXTAL  
10  
MΩ  
C.1.2  
Quartz Crystal Specification  
The following specifications for the quartz crystal are shown in the figure and table below.  
Resonance frequency (fs):  
Motional capacitance (Cm):  
Motional inductance (Lm):  
Resonance frequency of the crystal.  
Equivalent serial capacitance in the crystal model.  
Not generally given in supplier specification.  
Equivalent serial resistance in the crystal model. Some crystal  
providers refer to this resistance as the Equivalent Series  
Resistance (ESR) or simply Series Resistance.  
Motional resistance (Rm):  
Other providers supply a Quality Factor, Q, instead of Rm;  
therefore, the values for Q  
corresponding to specified range of Rm are supplied in the  
following table.  
Shunt capacitance (Co):  
Load capacitance (CL):  
Drive level:  
Parasitic capacitance between Q1 and Q2.  
Needed load capacitance viewed by the crystal to oscillate at fs.  
Power dissipated in the equivalent serial resistance (Rm).  
Resonance frequency shift due to aging.  
Aging:  
Co  
Q1  
Q2  
Cm  
Lm  
Rm  
Specification  
Minimum  
Typical  
Maximum  
Unit  
Hz  
Resonance frequency (fs)  
Quality factor (Q)  
32768  
80K  
3
40K  
2
200K  
4
Motional capacitance (Cm)  
Motional resistance (Rm)  
Shunt capacitance (Co)  
fF  
50K  
2
W
0.9  
pF  
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Load capacitance (CL)  
Drive level  
10  
12.5  
25  
pF  
1
µW  
o
o
Crystal type  
Tuning fork (X+5 or X+2 cut)  
The following values are not required for the crystal oscillator to function, but they directly affect  
the performance of the oscillator in the system because they determine the accuracy of the crystal  
itself. The values given represent those seen on typical crystals used for timekeeping, and are  
provided for information only.  
Specification  
Minimum  
Typical  
Maximum  
Unit  
Frequency tolerance  
Parabolic curvature  
Turnover temperature  
Temperature range  
Aging  
+/-5  
20  
0
+/-20  
-0.042  
25  
+/-30  
-0.05  
30  
ppm  
o
ppm/ C  
o
C
o
60  
C
+/-3  
+/-5  
ppm/year  
C-4  
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Internal Test  
Internal Test  
D
The Test Unit contains a register that enables certain test modes. Some of these test modes are  
reserved for manufacturing test and should not be invoked by an end user.  
D.1  
Test Unit Control Register (TUCR)  
The Test Unit Control Register (TUCR) contains control bits that put the Intel® StrongARM®  
SA-1100 Microprocessor (SA-1100) in various test modes. It is recommended that the operating  
system write protect these registers under normal conditions to prevent them from being  
inadvertently written. The following figure shows the format of this register. At reset reserved bits  
are zero. Writing reserved bits to one can lead to UNPREDICTABLE results.  
Bit 31  
30  
29  
28  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17 16  
Reserved  
R/W  
TSEL2 TSEL1 TSEL0  
Reset  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit 15  
R/W  
Reset  
14  
13  
12  
11  
10  
9
PMD  
8
7
6
5
4
3
2
1
Reserved  
MR  
Reserved  
0
0
0
0
0
0
0
0
0
0
0
0
A6071-02  
Bit  
0..5  
Name  
Description  
Reserved  
Reserved  
Reserved  
Reserved  
PMD  
6
7
8
9
Power management disable.  
When PMD is set, sleep mode is disabled and the SA-1100 ignores the  
ForceSleep bit, as well as the BATT_FAULT and VDD_Fault pins. This bit is  
cleared on hard reset.  
10  
MR  
Memory request mode. Controls two GPIO pins used for external arbitration and  
for the memory bus.  
0 – GP<21> and GP<22> are not used for an alternate function.  
1 – GP<21> and GP<22> are reserved for use as MBGNT and MBREQ,  
respectively.  
11..19  
20  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
21  
22  
23  
24  
25  
26  
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Internal Test  
Bit  
Name  
Description  
27..28 Reserved  
29..31 TSEL2-0  
Test selects. Routes internal signals out onto GPIO<27> for observing internal  
clock signals. To observe these clocks, set bit 27 to one in the GAFR and GPDR  
registers and set the TSEL bits to the following settings to select which clock is  
driven onto GP<27>:  
TSEL2  
TSEL1 TSEL0 GP<27>(alternate function)  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
32-kHz oscillator  
3.6864-MHz oscillator  
VDD ring oscillator/16  
96-MHz PLL/4  
32-kHz oscillator (also enable rclk on GP<26>  
3.6864-MHz oscillator  
Main PLL/16  
VDDL ring oscillator/4  
D-2  
SA-1100 Developer’s Manual  
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Support, Products, and Documentation  
If you need general information or support, call 1-800-628-8686 or visit Intel’s website at:  
http://www.intel.com  
Copies of documents that have an ordering number and are referenced in this document, a product  
catalog, or other Intel literature may be obtained by calling 1-800-548-4725 or by visiting Intel’s  
website for developers at:  
http://developer.intel.com  
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