TMS320C6472/TMS320TCI6486 DSP
Ethernet Media Access Controller (EMAC)/
Management Data Input/Output (MDIO) Module
User's Guide
Literature Number: SPRUEF8F
March 2006–Revised November 2010
Download from Www.Somanuals.com. All Manuals Search And Download.
Preface ...................................................................................................................................... 10
1
Introduction ...................................................................................................................... 11
1.1
1.2
1.3
1.4
Purpose of the Peripheral ............................................................................................. 11
Features ................................................................................................................. 11
Functional Block Diagram ............................................................................................. 12
Industry Standard(s) Compliance Statement ....................................................................... 14
2
EMAC Functional Architecture ............................................................................................ 15
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
Clock Control ........................................................................................................... 15
Memory Map ............................................................................................................ 16
System-Level Connections ........................................................................................... 17
Ethernet Protocol Overview .......................................................................................... 29
Programming Interface ................................................................................................ 31
Communications Port Programming Interface (CPPI) ............................................................ 40
Ethernet Multicore Interrupt Combiner (EMIC) Module ........................................................... 40
Management Data Input/Output (MDIO) Module .................................................................. 47
EMAC Module .......................................................................................................... 52
2.10 Media Independent Interfaces ........................................................................................ 54
2.11 Packet Receive Operation ............................................................................................ 58
2.12 Packet Transmit Operation ........................................................................................... 62
2.13 Receive and Transmit Latency ....................................................................................... 63
2.14 Transfer Node Priority ................................................................................................. 63
2.15 Reset Considerations .................................................................................................. 64
2.16 Initialization ............................................................................................................. 65
2.17 Interrupt Support ....................................................................................................... 67
2.18 Power Management ................................................................................................... 69
2.19 Emulation Considerations ............................................................................................. 69
EMIC Module Registers ...................................................................................................... 71
3
4
3.1
3.2
3.3
3.4
EW_INTCTL Registers ................................................................................................ 71
RPIC Registers ......................................................................................................... 71
TPIC Registers ......................................................................................................... 74
Prescalar Configuration Register (PSCFG) ........................................................................ 75
MDIO Registers ................................................................................................................. 76
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
Introduction ............................................................................................................. 76
MDIO Version Register (VERSION) ................................................................................. 77
MDIO Control Register (CONTROL) ................................................................................ 78
PHY Acknowledge Status Register (ALIVE) ....................................................................... 79
PHY Link Status Register (LINK) .................................................................................... 80
MDIO Link Status Change Interrupt (Unmasked) Register (LINKINTRAW) ................................... 81
MDIO Link Status Change Interrupt (Masked) Register (LINKINTMASKED) .................................. 82
4.10 MDIO User Command Complete Interrupt Mask Set Register (USERINTMASKSET) ....................... 85
3
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Table of Contents
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4.11 MDIO User Command Complete Interrupt Mask Clear Register (USERINTMASKCLEAR) ................. 86
4.12 MDIO User Access Register 0 (USERACCESS0) ................................................................ 87
4.13 MDIO User PHY Select Register 0 (USERPHYSEL0) ............................................................ 88
4.14 MDIO User Access Register 1 (USERACCESS1) ................................................................ 89
4.15 MDIO User PHY Select Register 1 (USERPHYSEL1) ............................................................ 90
EMAC Port Registers ......................................................................................................... 91
5
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
Transmit Identification and Version Register (TXIDVER) ........................................................ 95
Transmit Control Register (TXCONTROL) ......................................................................... 96
Transmit Teardown Register (TXTEARDOWN) ................................................................... 97
Receive Identification and Version Register (RXIDVER) ......................................................... 98
Receive Control Register (RXCONTROL) .......................................................................... 99
Receive Teardown Register (RXTEARDOWN) .................................................................. 100
Transmit Interrupt Status (Unmasked) Register (TXINTSTATRAW) .......................................... 101
Transmit Interrupt Status (Masked) Register (TXINTSTATMASKED) ........................................ 102
Transmit Interrupt Mask Set Register (TXINTMASKSET) ...................................................... 103
5.10 Transmit Interrupt Mask Clear Register (TXINTMASKCLEAR) ................................................ 104
5.11 MAC Input Vector Register (MACINVECTOR) ................................................................... 105
5.12 MAC End-of-Interrupt Vector Register (MACEOIVECTOR) .................................................... 106
5.13 Receive Interrupt Status (Unmasked) Register (RXINTSTATRAW) ........................................... 107
5.14 Receive Interrupt Status (Masked) Register (RXINTSTATMASKED) ......................................... 108
5.15 Receive Interrupt Mask Set Register (RXINTMASKSET) ....................................................... 109
5.16 Receive Interrupt Mask Clear Register (RXINTMASKCLEAR) ................................................. 110
5.17 MAC Interrupt Status (Unmasked) Register (MACINTSTATRAW) ............................................ 111
5.18 MAC Interrupt Status (Masked) Register (MACINTSTATMASKED) .......................................... 112
5.19 MAC Interrupt Mask Set Register (MACINTMASKSET) ........................................................ 113
5.20 MAC Interrupt Mask Clear Register (MACINTMASKCLEAR) .................................................. 114
5.21 Receive Multicast/Broadcast/Promiscuous Channel Enable Register (RXMBPENABLE) .................. 115
5.22 Receive Unicast Enable Set Register (RXUNICASTSET) ...................................................... 118
5.23 Receive Unicast Clear Register (RXUNICASTCLEAR) ......................................................... 119
5.24 Receive Maximum Length Register (RXMAXLEN) .............................................................. 120
5.25 Receive Buffer Offset Register (RXBUFFEROFFSET) ......................................................... 121
5.26 Receive Filter Low Priority Frame Threshold Register (RXFILTERLOWTHRESH) ......................... 122
5.27 Receive Channel 0-7 Flow Control Threshold Register (RXnFLOWTHRESH) .............................. 123
5.28 Receive Channel 0-7 Free Buffer Count Register (RXnFREEBUFFER) ..................................... 124
5.29 MAC Control Register (MACCONTROL) .......................................................................... 125
5.30 MAC Status Register (MACSTATUS) ............................................................................. 127
5.31 Emulation Control Register (EMCONTROL) ...................................................................... 129
5.32 FIFO Control Register (FIFOCONTROL) ......................................................................... 130
5.33 MAC Configuration Register (MACCONFIG) ..................................................................... 131
5.34 Soft Reset Register (SOFTRESET) ................................................................................ 132
5.35 MAC Source Address Low Bytes Register (MACSRCADDRLO) .............................................. 133
5.36 MAC Source Address High Bytes Register (MACSRCADDRHI) .............................................. 134
5.37 MAC Hash Address Register 1 (MACHASH1) ................................................................... 135
5.38 MAC Hash Address Register 2 (MACHASH2) ................................................................... 136
5.39 Back Off Test Register (BOFFTEST) .............................................................................. 137
5.40 Transmit Pacing Algorithm Test Register (TPACETEST) ....................................................... 138
5.41 Receive Pause Timer Register (RXPAUSE) ...................................................................... 139
5.42 Transmit Pause Timer Register (TXPAUSE) ..................................................................... 140
4
Contents
SPRUEF8F–March 2006–Revised November 2010
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5.43 MAC Address Low Bytes Register (MACADDRLO) ............................................................. 141
5.44 MAC Address High Bytes Register (MACADDRHI) ............................................................. 142
5.45 MAC Index Register (MACINDEX) ................................................................................. 143
5.46 Transmit Channel 0-7 DMA Head Descriptor Pointer Register (TXnHDP) ................................... 144
5.47 Receive Channel 0-7 DMA Head Descriptor Pointer Register (RXnHDP) .................................... 145
5.48 Transmit Channel 0-7 Completion Pointer Register (TXnCP) .................................................. 146
5.49 Receive Channel 0-7 Completion Pointer Register (RXnCP) .................................................. 147
5.50 Network Statistics Registers ........................................................................................ 148
Appendix A Glossary ............................................................................................................... 157
Appendix B Revision History ..................................................................................................... 159
5
SPRUEF8F–March 2006–Revised November 2010
Contents
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List of Figures
1
EMAC and MDIO Block Diagram........................................................................................ 12
Ethernet Configuration with MII Interface .............................................................................. 18
Ethernet Configuration with RMII Interface ............................................................................ 20
Ethernet Configuration with GMII Interface ............................................................................ 21
Ethernet Configuration with RGMII Interface .......................................................................... 23
Ethernet Configuration with S3MII Interface ........................................................................... 25
S3MII Multi-PHY Configuration .......................................................................................... 27
S3MII Switch Configuration .............................................................................................. 28
Ethernet Frame ............................................................................................................ 29
Basic Descriptor Format.................................................................................................. 31
Typical Descriptor Linked List............................................................................................ 32
Transmit Descriptor Format .............................................................................................. 34
Receive Descriptor Format............................................................................................... 37
EMIC Block Diagram...................................................................................................... 41
Pacing Block ............................................................................................................... 42
TDSM State Transition Diagram......................................................................................... 43
DSM State Transition Diagram .......................................................................................... 44
Transmit Pacer and Interrupt Combiner ................................................................................ 45
Receive Pacer and Interrupt Combiner................................................................................. 46
Common Interrupt Combiner............................................................................................. 47
MDIO Module Block Diagram............................................................................................ 48
EMAC Module Block Diagram ........................................................................................... 52
EW_INTCTL Register..................................................................................................... 71
RPCFG Register........................................................................................................... 72
RPSTAT Register ......................................................................................................... 73
TPCFG Register ........................................................................................................... 74
TPSTAT Register.......................................................................................................... 75
Prescalar Configuration Register (PSCFG) ............................................................................ 75
MDIO Version Register (VERSION) .................................................................................... 77
MDIO Control Register (CONTROL).................................................................................... 78
PHY Acknowledge Status Register (ALIVE) ........................................................................... 79
PHY Link Status Register (LINK)........................................................................................ 80
MDIO Link Status Change Interrupt (Unmasked) Register (LINKINTRAW) ....................................... 81
MDIO Link Status Change Interrupt (Masked) Register (LINKINTMASKED) ..................................... 82
MDIO User Command Complete Interrupt (Unmasked) Register (USERINTRAW).............................. 83
MDIO User Command Complete Interrupt (Masked) Register (USERINTMASKED) ............................ 84
MDIO User Command Complete Interrupt Mask Set Register (USERINTMASKSET)........................... 85
MDIO User Access Register 0 (USERACCESS0) .................................................................... 87
MDIO User PHY Select Register 0 (USERPHYSEL0) ............................................................... 88
MDIO User Access Register 1 (USERACCESS1) .................................................................... 89
MDIO User PHY Select Register 1 (USERPHYSEL1) ............................................................... 90
Transmit Identification and Version Register (TXIDVER) ............................................................ 95
Transmit Control Register (TXCONTROL)............................................................................. 96
Transmit Teardown Register (TXTEARDOWN) ....................................................................... 97
Receive Identification and Version Register (RXIDVER)............................................................. 98
Receive Control Register (RXCONTROL) ............................................................................. 99
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
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29
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31
32
33
34
35
36
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39
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41
42
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44
45
46
47
6
List of Figures
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48
49
50
51
52
53
54
55
56
57
58
59
60
61
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63
64
65
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75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
Receive Teardown Register (RXTEARDOWN) ...................................................................... 100
Transmit Interrupt Status (Unmasked) Register (TXINTSTATRAW).............................................. 101
Transmit Interrupt Status (Masked) Register (TXINTSTATMASKED) ............................................ 102
Transmit Interrupt Mask Set Register (TXINTMASKSET).......................................................... 103
Transmit Interrupt Mask Clear Register (TXINTMASKCLEAR).................................................... 104
MAC Input Vector Register (MACINVECTOR)....................................................................... 105
MAC End-of-Interrupt Vector Register (MACEOIVECTOR)........................................................ 106
Receive Interrupt Status (Unmasked) Register (RXINTSTATRAW) .............................................. 107
Receive Interrupt Status (Masked) Register (RXINTSTATMASKED)............................................. 108
Receive Interrupt Mask Set Register (RXINTMASKSET) .......................................................... 109
Receive Interrupt Mask Clear Register (RXINTMASKCLEAR) .................................................... 110
MAC Interrupt Status (Unmasked) Register (MACINTSTATRAW)................................................ 111
MAC Interrupt Status (Masked) Register (MACINTSTATMASKED) .............................................. 112
MAC Interrupt Mask Set Register (MACINTMASKSET)............................................................ 113
MAC Interrupt Mask Clear Register (MACINTMASKCLEAR)...................................................... 114
Receive Multicast/Broadcast/Promiscuous Channel Enable Register (RXMBPENABLE) ..................... 115
Receive Unicast Enable Set Register (RXUNICASTSET).......................................................... 118
Receive Unicast Clear Register (RXUNICASTCLEAR)............................................................. 119
Receive Maximum Length Register (RXMAXLEN).................................................................. 120
Receive Buffer Offset Register (RXBUFFEROFFSET) ............................................................. 121
Receive Filter Low Priority Frame Threshold Register (RXFILTERLOWTHRESH)............................. 122
Receive Channel n Flow Control Threshold Register (RXnFLOWTHRESH) .................................... 123
Receive Channel n Free Buffer Count Register (RXnFREEBUFFER) ........................................... 124
MAC Control Register (MACCONTROL) ............................................................................. 125
MAC Status Register (MACSTATUS)................................................................................. 127
Emulation Control Register (EMCONTROL) ......................................................................... 129
FIFO Control Register (FIFOCONTROL) ............................................................................. 130
MAC Configuration Register (MACCONFIG)......................................................................... 131
Soft Reset Register (SOFTRESET) ................................................................................... 132
MAC Source Address Low Bytes Register (MACSRCADDRLO).................................................. 133
MAC Source Address High Bytes Register (MACSRCADDRHI) .................................................. 134
MAC Hash Address Register 1 (MACHASH1)....................................................................... 135
MAC Hash Address Register 2 (MACHASH2)....................................................................... 136
Back Off Test Register (BOFFTEST) ................................................................................. 137
Transmit Pacing Algorithm Test Register (TPACETEST) .......................................................... 138
Receive Pause Timer Register (RXPAUSE) ......................................................................... 139
Transmit Pause Timer Register (TXPAUSE)......................................................................... 140
MAC Address Low Bytes Register (MACADDRLO)................................................................. 141
MAC Address High Bytes Register (MACADDRHI) ................................................................. 142
MAC Index Register (MACINDEX) .................................................................................... 143
Transmit Channel n DMA Head Descriptor Pointer Register (TXnHDP) ......................................... 144
Receive Channel n DMA Head Descriptor Pointer Register (RXnHDP).......................................... 145
Transmit Channel n Completion Pointer Register (TXnCP)........................................................ 146
Receive Channel n Completion Pointer Register (RXnCP) ........................................................ 147
Statistics Register........................................................................................................ 148
7
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List of Figures
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List of Tables
1
Serial Management Interface Pins ...................................................................................... 13
EMAC1_EN Pin Description ............................................................................................. 13
EMAC Clock Specifications .............................................................................................. 15
EMAC0 Interface Selection Pins ........................................................................................ 17
EMAC1 Interface Selection Pins ........................................................................................ 17
MACSEL0[2:0], MACSEL1[1:0], and EMAC1_EN Decoding ........................................................ 17
EMAC and MDIO Signals for MII Interface............................................................................. 19
EMAC and MDIO Signals for RMII Interface........................................................................... 20
EMAC and MDIO Signals for GMII Interface .......................................................................... 22
EMAC and MDIO Signals for RGMII Interface ........................................................................ 23
EMAC and MDIO Signals for S3MII Interface ......................................................................... 26
Ethernet Frame Description.............................................................................................. 29
Basic Descriptors.......................................................................................................... 31
Receive Frame Treatment Summary ................................................................................... 61
Middle-of-Frame Overrun Treatment.................................................................................... 62
Emulation Control ......................................................................................................... 70
RPCFG Register Field Descriptions .................................................................................... 72
RPSTAT Register Field Descriptions ................................................................................... 73
TPCFG Register Field Descriptions..................................................................................... 74
TPSTAT Register Field Descriptions ................................................................................... 75
Management Data Input/Output (MDIO) Registers ................................................................... 76
MDIO Version Register (VERSION) Field Descriptions .............................................................. 77
MDIO Control Register (CONTROL) Field Descriptions ............................................................. 78
PHY Acknowledge Status Register (ALIVE) Field Descriptions..................................................... 79
PHY Link Status Register (LINK) Field Descriptions ................................................................. 80
MDIO Link Status Change Interrupt (Unmasked) Register (LINKINTRAW) Field Descriptions................. 81
MDIO Link Status Change Interrupt (Masked) Register (LINKINTMASKED) Field Descriptions ............... 82
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MDIO User Command Complete Interrupt Mask Clear Register (USERINTMASKCLEAR) Field
Descriptions ................................................................................................................ 86
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
MDIO User Access Register 0 (USERACCESS0) Field Descriptions.............................................. 87
MDIO User PHY Select Register 0 (USERPHYSEL0) Field Descriptions ......................................... 88
MDIO User Access Register 1 (USERACCESS1) Field Descriptions.............................................. 89
MDIO User PHY Select Register 1 (USERPHYSEL1) Field Descriptions ......................................... 90
Ethernet Media Access Controller (EMAC) Registers ................................................................ 91
Transmit Identification and Version Register (TXIDVER) Field Descriptions...................................... 95
Transmit Control Register (TXCONTROL) Field Descriptions....................................................... 96
Transmit Teardown Register (TXTEARDOWN) Field Descriptions................................................. 97
Receive Identification and Version Register (RXIDVER) Field Descriptions ...................................... 98
Receive Control Register (RXCONTROL) Field Descriptions ....................................................... 99
Receive Teardown Register (RXTEARDOWN) Field Descriptions................................................ 100
Transmit Interrupt Status (Unmasked) Register (TXINTSTATRAW) Field Descriptions ....................... 101
Transmit Interrupt Status (Masked) Register (TXINTSTATMASKED) Field Descriptions...................... 102
Transmit Interrupt Mask Set Register (TXINTMASKSET) Field Descriptions.................................... 103
Transmit Interrupt Mask Clear Register (TXINTMASKCLEAR) Field Descriptions ............................. 104
8
List of Tables
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47
48
49
50
51
52
53
54
55
56
57
MAC Input Vector Register (MACINVECTOR) Field Descriptions ................................................ 105
MAC End-of-Interrupt Vector Register (MACEOIVECTOR) Field Descriptions.................................. 106
Receive Interrupt Status (Unmasked) Register (RXINTSTATRAW) Field Descriptions........................ 107
Receive Interrupt Status (Masked) Register (RXINTSTATMASKED) Field Descriptions ...................... 108
Receive Interrupt Mask Set Register (RXINTMASKSET) Field Descriptions .................................... 109
Receive Interrupt Mask Clear Register (RXINTMASKCLEAR) Field Descriptions.............................. 110
MAC Interrupt Status (Unmasked) Register (MACINTSTATRAW) Field Descriptions ......................... 111
MAC Interrupt Status (Masked) Register (MACINTSTATMASKED) Field Descriptions........................ 112
MAC Interrupt Mask Set Register (MACINTMASKSET) Field Descriptions ..................................... 113
MAC Interrupt Mask Clear Register (MACINTMASKCLEAR) Field Descriptions ............................... 114
Receive Multicast/Broadcast/Promiscuous Channel Enable Register (RXMBPENABLE) Field
Descriptions............................................................................................................... 115
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
Receive Unicast Enable Set Register (RXUNICASTSET) Field Descriptions ................................... 118
Receive Unicast Clear Register (RXUNICASTCLEAR) Field Descriptions ...................................... 119
Receive Maximum Length Register (RXMAXLEN) Field Descriptions............................................ 120
Receive Buffer Offset Register (RXBUFFEROFFSET) Field Descriptions....................................... 121
Receive Filter Low Priority Frame Threshold Register (RXFILTERLOWTHRESH) Field Descriptions ...... 122
Receive Channel n Flow Control Threshold Register (RXnFLOWTHRESH) Field Descriptions.............. 123
Receive Channel n Free Buffer Count Register (RXnFREEBUFFER) Field Descriptions ..................... 124
MAC Control Register (MACCONTROL) Field Descriptions ....................................................... 125
MAC Status Register (MACSTATUS) Field Descriptions........................................................... 127
Emulation Control Register (EMCONTROL) Field Descriptions ................................................... 129
FIFO Control Register (FIFOCONTROL) Field Descriptions....................................................... 130
MAC Configuration Register (MACCONFIG) Field Descriptions .................................................. 131
Soft Reset Register (SOFTRESET) Field Descriptions............................................................. 132
MAC Source Address Low Bytes Register (MACSRCADDRLO) Field Descriptions ........................... 133
MAC Source Address High Bytes Register (MACSRCADDRHI) Field Descriptions............................ 134
MAC Hash Address Register 1 (MACHASH1) Field Descriptions................................................. 135
MAC Hash Address Register 2 (MACHASH2) Field Descriptions................................................. 136
Back Off Test Register (BOFFTEST) Field Descriptions ........................................................... 137
Transmit Pacing Algorithm Test Register (TPACETEST) Field Descriptions .................................... 138
Receive Pause Timer Register (RXPAUSE) Field Descriptions................................................... 139
Transmit Pause Timer Register (TXPAUSE) Field Descriptions .................................................. 140
MAC Address Low Bytes Register (MACADDRLO) Field Descriptions .......................................... 141
MAC Address High Bytes Register (MACADDRHI) Field Descriptions........................................... 142
MAC Index Register (MACINDEX) Field Descriptions .............................................................. 143
Transmit Channel n DMA Head Descriptor Pointer Register (TXnHDP) Field Descriptions................... 144
Receive Channel n DMA Head Descriptor Pointer Register (RXnHDP) Field Descriptions ................... 145
Transmit Channel n Completion Pointer Register (TXnCP) Field Descriptions.................................. 146
Receive Channel n Completion Pointer Register (RXnCP) Field Descriptions .................................. 147
Statistics Register Field Descriptions.................................................................................. 148
EMAC/MDIO Revision History.......................................................................................... 159
9
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List of Tables
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Preface
SPRUEF8F–March 2006–Revised November 2010
Read This First
About This Manual
This document provides a functional description of the Ethernet Media Access Controller (EMAC) and
Physical layer (PHY) device Management Data Input/Output (MDIO) module integrated with
TMS320TCI6486/TMS320C6472 devices. Included are the features of the EMAC and MDIO modules, a
discussion of their architecture and operation, how these modules connect to the outside world, and the
registers descriptions for each module.
Notational Conventions
This document uses the following conventions.
•
Hexadecimal numbers are shown with the suffix h. For example, the following number is 40
hexadecimal (decimal 64): 40h.
•
Registers in this document are shown in figures and described in tables.
–
Each register figure shows a rectangle divided into fields that represent the fields of the register.
Each field is labeled with its bit name, its beginning and ending bit numbers above, and its
read/write properties below. A legend explains the notation used for the properties.
–
Reserved bits in a register figure designate a bit that is used for future device expansion.
Related Documentation From Texas Instruments
The following documents describe the C6000™ devices and related support tools. Copies of these
documents are available on the Internet. Tip: Enter the literature number in the search box provided at
www.ti.com.
architecture, pipeline, instruction set, and interrupts for the TMS320C6000 digital signal processors
(DSPs).
the TMS320C6000™ DSPs and includes application program examples.
integrated development environment and software tools.
Describes the Code Composer Studio™ application programming interface (API), which allows you
to program custom plug-ins for Code Composer.
processor (DSP) megamodule. Included is a discussion on the internal direct memory access
(IDMA) controller, the interrupt controller, the power-down controller, memory protection, bandwidth
management, and the memory and cache.
C6000, TMS320C6000, Code Composer Studio are trademarks of Texas Instruments.
All other trademarks are the property of their respective owners.
10
Preface
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User's Guide
SPRUEF8F–March 2006–Revised November 2010
C6472/TCI6486 EMAC/MDIO
1
Introduction
This document provides a functional description of the Ethernet Media Access Controller (EMAC) and
Physical layer (PHY) device Management Data Input/Output (MDIO) module integrated with
TMS320TCI6486/TMS320C6472 devices. Included are the features of the EMAC and MDIO modules, a
discussion of their architecture and operation, how these modules connect to the outside world, and the
registers descriptions for each module.
The EMAC controls the flow of packet data from the processor to the PHY. The MDIO module controls
PHY configuration and status monitoring.
Both the EMAC and the MDIO modules interface to the DSP through EMIC modules and CPPI buffer
managers that allow efficient data transmission and reception. These two modules are considered integral
to the EMAC/MDIO peripheral.
1.1 Purpose of the Peripheral
The EMAC module is used on TMS320TCI6486/TMS320C6472 devices to move data between the device
and another host connected to the same network, in compliance with the Ethernet protocol.
1.2 Features
Two EMAC modules are integrated with the TCI6486/C6472 device. The basic feature set of the
integrated EMAC modules is:
•
•
•
•
Synchronous 10/100/1000-Mbps operation.
Full duplex Gigabit operation (half duplex gigabit is not supported).
Little endian and big endian support.
Both EMAC modules support three types of interfaces to the physical layer device (PHY): reduced
pin-count media independent interface (RMII), reduced pin-count gigabit media independent interface
(RGMII), and source synchronous serial independent interface (S3MII).
•
In addition to above four EMAC0 natively supports an additional two interfaces: standard media
independent interface (MII) and standard gigabit media independent interface (GMII).
•
•
•
•
•
•
•
•
EMAC acts as DMA master to either internal or external device memory space.
Eight receive channels with VLAN tag discrimination for receive quality-of-service (QOS) support.
Eight transmit channels with round-robin or fixed priority for transmit quality-of-service (QOS) support.
Ether-stats and 802.3-stats statistics gathering.
Transmit CRC generation selectable on a per-channel basis.
Broadcast frames selection for reception on a single channel.
Multicast frames selection for reception on a single channel.
Promiscuous receive mode frames selection for reception on a single channel (all frames, all good
frames, short frames, error frames).
•
•
•
•
•
Hardware flow control.
CPPI 3.0 compliant.
TI adaptive performance optimization for improved half duplex performance.
Ethernet Multicore Interrupt Combiner (EMIC) for EMAC and MDIO interrupts.
Programmable interrupt logic permits the software driver to restrict the generation of back-to-back
interrupts, thus, allowing more work to be performed in a single call to the interrupt service routine.
11
SPRUEF8F–March 2006–Revised November 2010
C6472/TCI6486 EMAC/MDIO
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•
Single MDIO, shared by both EMAC modules.
1.3 Functional Block Diagram
Figure 1 shows the functional block diagram of the EMAC peripherals used in the TCI6486/C6472 device.
It consists mainly of:
•
•
•
•
•
EMAC0
EMAC1
CPPI buffer manager per EMAC
EMIC per EMAC
MDIO
Figure 1. EMAC and MDIO Block Diagram
To GEMs
EMAC
Control 0
Module
EMIC0
DMA
memory
transfer control
MII0/GMII0
S3MII0
CPPI buffer
manager +
CPPI RAM0
EMAC0
RMII0
RGMII0
Peripheral
bus
MDIO
To PHYs
CPPI buffer
manager +
CPPI RAM1
S3MII1
RMII1
EMAC1
DMA
memory
transfer control
RGMII1
EMIC1
EMAC
Control 1
Module
To GEMs
12
C6472/TCI6486 EMAC/MDIO
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Introduction
The EMAC module provides an efficient interface between the TCI6486/C6472 core processor and the
networked community. The EMAC supports 10Base-T (10 Mbits/sec) and 100Base-TX (100 Mbits/sec) in
either half- or full-duplex mode, and 1000Base-T (1000 Mbits/sec) in full-duplex mode, with hardware flow
control and quality-of-service (QOS) support.
Each EMAC module has a communications port programming interface (CPPI) buffer manager to manage
8K of CPPI RAM. The EMAC uses four 32-bit words as buffer descriptors that point to different buffers in
the DSP memory. The CPUs create and maintain these buffer descriptors. The EMAC reads from and
writes to these buffer descriptors as it transfers data to or from the buffers.
The EMIC module associated with each EMAC takes a single set of interrupts from respective EMAC and
common MDIO and creates six different sets of TX, RX, and common interrupts to six cores of the
TCI6486/C6472 device. In addition, this module implements the interrupt pacing operation.
The control registers of the EMAC and MDIO modules are memory mapped into device memory space via
the device configuration bus.
The MDIO module implements the 802.3 serial management interface to interrogate and control up to 32
Ethernet PHYs connected to the device, using a shared two-wire bus. Application software uses the MDIO
module to configure the auto-negotiation parameters of each PHY attached to the EMAC, retrieve the
negotiation results, and configure required parameters in the EMAC module for correct operation. The
module is designed to allow almost transparent operation of the MDIO interface, with very little
maintenance from the core processor. A single MDIO is shared by both EMACs.
MACSEL0[2:0] and MACSEL1[1:0] are device configuration pins used to select the MII interface for
EMAC0 and EMAC1, respectively.
The MDIO communicates to PHY through two signals: MDCLK (output clock) and MDIO (bi-directional
data). For details of MDIO operation and signals, see Section 2.8. The device has two serial management
interfaces, although only one is used based on the interface selection of EMAC0. Table 1 shows the two
sets of pins associated with serial management interface. One serial management interface is for RGMII
(needed at 1.8-V HSTL buffer) and the other serial management interface is for non-RGMII interfaces
(needed at 3.3-V LVCMOS buffers).
Table 1. Serial Management Interface Pins
Signal
Description
GMDCLK
GMDIO
MII/GMII/RMII/S3MII management clock. Available on 3.3-V LVCMOS buffers.
MII/GMII/RMII/S3MII management data. Available on 3.3-V LVCMOS buffers.
RGMII management clock. Available on 1.8-V HSTL buffers.
RGMII management data. Available on 1.8-V HSTL buffers.
RGMDCLK
RGMDIO
As mentioned above, the management interface selection is based on the interface selection for EMAC0.
If MACSEL0 is programmed to select RGMII0, the 1.8-V serial management interface is selected
(RGMDIO, RGMDCLK), otherwise, the 3.3-V (GMDIO, GMDCLK) management interface is selected. Due
to this programmed selection, in some cases level shifters may have to be used for the management
interface. As an example, if the RGMII0 interface is selected for EMAC0 and the S3MII1 interface is
selected for EMAC1, the 1.8-V serial management interface (RGMDCLK and RGMDIO) is used. Since
S3MII PHY needs the 3.3-V management interface, level shifters have to be used to level translate these
HSTL pins.
Also note that EMAC1 can be enabled or disabled using the EMAC1_EN internal pulldown pin that
controls the I/O signals of EMAC1. The EMAC1_EN is also latched into the bit 12 of the DEVCTL register.
Table 2 describes the EMAC1_EN pin.
Table 2. EMAC1_EN Pin Description
Value
Description
0
EMAC1 is disabled or not used.
Pulls on EMAC1 I/O are enabled (except RGMII pins) and the corresponding I/O
buffers are powered down.
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Table 2. EMAC1_EN Pin Description (continued)
Value
Description
1
EMAC1 is enabled and used.
Pulls on EMAC1 I/O are disabled (except RGMII pins) and the corresponding I/O
buffers are powered up except RGMII output-only pins.
NOTE: RGMII buffers are HSTL buffers with no internal pulls. RGMII output only pins will always
be powered down even when the module is enabled.
EMAC1_EN is also software programmable through the DEVCTL register. A write to the DEVCTL register
is key-protected by the DEVCTL_KEY register. For details of MACSEL0, MACSEL1, and EMAC1_EN
1.4 Industry Standard(s) Compliance Statement
The EMAC peripheral conforms to the IEEE 802.3 standard, describing the Carrier Sense Multiple Access
with Collision Detection (CSMA/CD) Access Method and Physical Layer specifications. ISO/IEC has also
adopted the IEEE 802.3 standard and re-designated it as ISO/IEC 8802-3:2000(E).
In difference from this standard, the EMAC peripheral integrated with the TCI6486/C6472 device does not
use the transmit coding error signal MTXER. Instead of driving the error pin when an underflow condition
occurs on a transmitted frame, the EMAC intentionally generates an incorrect check sum by inverting the
frame CRC so that the network detects the transmitted frame as an error.
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EMAC Functional Architecture
2
EMAC Functional Architecture
This section discusses the architecture and basic function of the EMAC peripheral.
2.1 Clock Control
The frequencies for the transmit and receive clocks are fixed by the IEEE 802.3 specification, as shown
below:
•
•
•
2.5 MHz at 10 Mbps
25 MHz at 100 Mbps
125 MHz at 1000 Mbps
All clock sources, with the exception of the EMAC peripheral bus clock, are sourced from the PLL2
controller. The PLL2 controller has 3 clocks for EMAC0: SYSCLK13, SYSCLK14, and SYSCLK15. For
EMAC0 operation, the SYSCLK14 divider is programmable and other clocks are fixed. The PLL multiplier
value of the PLL2 controller is also fixed. The PLL2 controller has 3 clocks for EMAC1: SYSCLK16,
SYSCLK17, and SYSCLK18. These clocks should remain fixed.
Table 3. EMAC Clock Specifications
Clock
Divider
Frequency
Purpose
SYSCLK13
/2
250 MHz
Used for RGMII0 only
/10 or
/4
50 or
125 MHz
50 MHz used for RGMII (default
125 MHz used for GMII
SYSCLK14
SYSCLK15
SYSCLK16
SYSCLK17
SYSCLK18
/100
/2
5 MHz
250 MHz
50 MHz
5 MHz
Used for RGMII0 only
Used for RGMII1 only
Used for RGMII1 (default)
Used for RGMII1 only
/10
/100
2.1.1
2.1.2
MII Clocking
The MII interface is supported by EMAC0 only. When MACSEL0 is set to zero (000b), the transmit and
receive clock sources are provided from an external PHY via the MTCLK and MRCLK pins. These clocks
are inputs to the EMAC module and operate at 2.5 MHz in 10-Mbps mode and at 25 MHz in 100-MHz
mode. The MII clocking interface is not used in 1000-Mbps mode. For timing purposes, data is transmitted
and received with reference to MTCLK and MRCLK, respectively.
RMII Clocking
The RMII interface is selected when MACSEL0 is set to 1 (001b) or MACSEL1 is set to 3 (11b). RMII
requires two clock sources, the peripheral bus clock and the reference clock (REF_CLK), input to the RMII
gasket. A 50-MHz clock from device input pin REFCLKx is supplied to the REF_CLK input of the RMII
gasket. The EMAC clocks the transmit and receive operations from the reference clock. The MTCLK and
MRCLK device pins are not used for this interface. The RMII protocol turns one data phase of an MII
transfer into two data phases at double the clock frequency. This is the driving factor for the 50-MHz
reference clock. Data at the I/O pins are running at 5 MHz in 10-Mbps mode and at 50 MHz in 100-Mbps
mode.
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2.1.3
GMII Clocking
The GMII interface is available only on EMAC0 and requires two clock sources generated internally, the
peripheral bus clock and the RFTCLK inputs to the EMAC module. SYSCLK14 is programmed to /4 for
this interface to provide a 125-MHz clock to the RFTCLK input of EMAC. The GMII interface is selected by
programming MACSEL0 to 2 (010b). Transmit and receive clock sources for 10/100-Mbps modes are
provided from an external PHY via the MTCLK and MRCLK pins. For 1000-Mbps mode, the receive clock
is provided by an external PHY via the MRCLK pin. For transmit in 1000-Mbps mode, the clock is sourced
synchronous with the data, and is provided by the EMAC to be output on the GMTCLK pin.
For timing purposes, data in 10/100-Mbps mode is transmitted and received with reference to MTCLK and
MRCLK, respectively. For 1000-Mbps mode, receive timing is the same, but transmit is relative to
GMTCLK.
2.1.4
RGMII Clocking
The RGMII interface is selected by programming MACSEL0 to 3 (011b) and MACSEL1 to 2 (10b). RGMII
requires 4 internally generated clocks; peripheral bus clock and three reference clocks. The EMAC drives
the transmit clock, while an external PHY generates the receive clock. The reference clock drives the
device pin that gives the 125-MHz clock to the PHY; this enables the PHY to generate the receive clock
that is sent to EMAC.
The RGMII protocol takes a GMII data stream and turns it into an interface with half of the data bus width
and sends the same amount of data with a reduced pinout. The RGMII protocol also allows for dynamic
switching of the mode between 10/100/1000-Mbps modes. This negotiation data is embedded in the
incoming data stream from the external PHY. For timing purposes, data is transmitted and received with
respect to MTCLK and MRCLK, respectively.
The RGMII interface has separate I/O pins from the other EMAC pins because the interface voltage is
different from the other interfaces.
2.1.5
S3MII Clocking
S3MII mode is selected by programming MACSEL0 to 5 (101b) and MACSEL1 to 1 (01b). The S3MII
gasket needs a 125-MHz continuous clock (125_CLK) supplied by an external source. It also needs a
peripheral bus clock as input. MTCLK and MRCLK are fixed at 125 MHz.
2.2 Memory Map
The EMAC includes an internal memory that holds information about the Ethernet packets that are
received or transmitted. This internal RAM is 2K x 32 bits in size. The data can be written to and read from
the EMAC internal memory via either the EMAC or the CPU. It stores buffer descriptors that are 4 words
(16 bytes) deep. This 8K local memory holds enough information to transfer up to 512 Ethernet packets
without CPU intervention.
The packet buffer descriptors can be put in internal processor memory (L2) on the TCI6486/C6472 device.
There are some trade-offs in terms of cache performance and throughput when the descriptors are put in
L2 versus when they are put in EMAC internal memory. The cache performance improves when the buffer
descriptors are put in the internal memory. However, the EMAC throughput is better when the descriptors
are put in the local EMAC RAM.
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EMAC Functional Architecture
2.3 System-Level Connections
On the TCI6486/C6472 device, EMAC0 and EMAC1 support the following different types of interfaces to
physical layer devices (PHYs) or switches. Each EMAC can be configured to only one interface at any
Table 4. EMAC0 Interface Selection Pins
MACSEL0 [2:0]
Interface
MII
000
001
010
011
100
101
110
111
RMII
GMII
RGMII
Not used
S3MII
Not used
Not used
Table 5. EMAC1 Interface Selection Pins
MACSEL1 [1:0]
Interface
Not used
S3MII
00
01
10
11
RGMII
RMII
Table 6 explains the decoding of MACSEL0 [2:0], MACSEL1[1:0], and EMAC1_EN of the DEVCTL
register.
Table 6. MACSEL0[2:0], MACSEL1[1:0], and EMAC1_EN Decoding
MACSEL02
MACSEL01
MACSEL00
MACSEL11
MACSEL10
EMAC_EN
EMAC0
MII
EMAC1
None
None
RGMII
None
None
RGMII
None
None
None
None
None
S3MII
RGMII
RMII
0
0
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
1
1
1
0
0
0
1
1
1
0
1
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
1
1
0
1
1
1
1
1
1
1
1
1
0
0
0
X
0
1
X
0
1
X
X
X
X
0
0
1
1
0
0
1
1
0
0
1
X
X
0
X
X
0
X
X
X
X
0
1
0
1
0
1
0
1
0
1
0
0
1
1
0
1
1
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
MII
MII
GMII
GMII
GMII
RMII
RGMII
None
S3MII
RMII
RMII
RMII
RMII
RGMII
RGMII
RGMII
RGMII
None
None
None
None
S3MII
RGMII
RMII
None
S3MII
RGMII
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Table 6. MACSEL0[2:0], MACSEL1[1:0], and EMAC1_EN Decoding (continued)
MACSEL02
MACSEL01
MACSEL00
MACSEL11
MACSEL10
EMAC_EN
EMAC0
None
S3MII
S3MII
S3MII
S3MII
None
None
None
None
None
EMAC1
RMII
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
1
1
1
1
1
0
1
1
1
1
1
1
1
1
1
1
0
0
1
1
X
0
0
1
1
1
0
1
0
1
X
0
1
0
1
1
1
1
1
1
0
1
1
1
1
None
S3MII
RGMII
RMII
None
None
S3MII
RGMII
RMII
2.3.1
Media Independent Interface (MII) Connections
Figure 2 shows a TCI6486/C6472 device with integrated EMAC and MDIO interfaced to the PHY via an
MII connection. This interface is only available in 10 Mbps and 100 Mbps modes.
Figure 2. Ethernet Configuration with MII Interface
MTCLK
MTXD[3−0]
2.5 MHZ
MTXEN
or
25 MHz
MCOL
MCRS
Physical
layer
device
(PHY)
System
core
MRCLK
Transformer
RJ-45
MRXD[3−0]
MRXDV
MRXER
MDCLK
MDIO
Table 7 summarizes the individual EMAC and MDIO signals for the MII interface. For more information,
refer to either the IEEE 802.3 standard or ISO/IEC 8802-3:2000(E).
The EMAC module does not include a transmit error (MTXER) pin. If a transmit error occurs, CRC
inversion is used to negate the validity of the transmitted frame.
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EMAC Functional Architecture
Table 7. EMAC and MDIO Signals for MII Interface
Signal Name
I/O
Description
MTCLK
I
Transmit clock (MTCLK). The transmit clock is a continuous clock that provides the timing reference
for transmit operations. The MTXD and MTXEN signals are tied to this clock. The clock is generated
by the PHY and is 2.5 MHz at 10-Mbps operation and 25 MHz at 100-Mbps operation.
MTXD[3:0]
O
Transmit data (MTXD). The transmit data pins are a collection of 4 data signals comprising 4 bits of
data. MTDX0 is the least-significant bit (LSB). The signals are synchronized by MTCLK and valid
only when MTXEN is asserted.
MTXEN
MCOL
O
I
Transmit enable (MTXEN). The transmit enable signal indicates that the MTXD pins are generating
nibble data for use by the PHY. It is driven synchronously to MTCLK.
Collision detected (MCOL). The MCOL pin is asserted by the PHY when it detects a collision on the
network. It remains asserted while the collision condition persists. This signal is not necessarily
synchronous to MTCLK nor MRCLK. This pin is used in half-duplex operation only.
MCRS
I
I
I
Carrier sense (MCRS). The MCRS pin is asserted by the PHY when the network is not idle in either
transmit or receive. The pin is de-asserted when both transmit and receive are idle. This signal is not
necessarily synchronous to MTCLK or MRCLK. This pin is used in half-duplex operation only.
MRCLK
MRXD[3:0]
Receive clock (MRCLK). The receive clock is a continuous clock that provides the timing reference
for receive operations. The MRXD, MRXDV, and MRXER signals are tied to this clock. The clock is
generated by the PHY and is 2.5 MHz at 10-Mbps operation and 25 MHz at 100-Mbps operation.
Receive data (MRXD). The receive data pins are a collection of 4 data signals comprising 4 bits of
data. MRDX0 is the least-significant bit (LSB). The signals are synchronized by MRCLK and valid
only when MRXDV is asserted.
MRXDV
MRXER
I
I
Receive data valid (MRXDV). The receive data valid signal indicates that the MRXD pins are
generating nibble data for use by the EMAC. It is driven synchronously to MRCLK.
Receive error (MRXER). The receive error signal is asserted for one or more MRCLK periods to
indicate that an error was detected in the received frame. This is meaningful only during data
reception when MRXDV is active.
MDCLK
MDIO
O
Management data clock (MDCLK). The MDIO data clock is sourced by the MDIO module on the
system. It is used to synchronize MDIO data access operations done on the MDIO pin. The
frequency of this clock is controlled by the CLKDIV bits in the MDIO control register (CONTROL).
I/O
Management data input output (MDIO). The MDIO pin drives PHY management data into and out of
the PHY by way of an access frame consisting of start of frame, read/write indication, PHY address,
register address, and data bit cycles. The MDIO pin acts as an output for everything except the data
bit cycles, when the pin acts as an input for read operations.
When the device is interfaced to an Ethernet switch via an MII interface, the carrier sense (MCRS) and
collision (MCOL) signals are not necessary since full-duplex operation is forced.
On the TCI6486/C6472 device, the MII Ethernet interface is available only on EMAC0. MII0 pins are
multiplexed with other non-RGMII pins (RMII1, S3MII1). due to this multiplexing, when the MII0 interface is
selected on EMAC0, except for RGMII1, no Ethernet interface is available on EMAC1.
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2.3.2
Reduced Media Independent Interface (RMII) Connections
Figure 3 shows a TCI6486/C6472 device with integrated EMAC and MDIO interfaced to the PHY via an
RMII connection. This interface is available only in 10-Mbps and 100-Mbps modes.
Figure 3. Ethernet Configuration with RMII Interface
50-MHz
50-MHz
zero-delay
XO
clock buffer
RMREFCLK
RMREFCLK
RMTXD[1−0]
RMTXEN
RMCRSDV
RMRXD[1−0]
RMRXER
Physical
layer
device
(PHY)
System
core
MDCLK
MDIO
The RMII interface has the same functionality as the MII, but it does so with a reduced number of pins,
thus lowering the total cost for an application. In devices incorporating many PHY interfaces such as
switches, the number of pins can add significant cost as the port counts increase. Table 8 summarizes the
individual EMAC and MDIO signals for the RMII interface.
The RMII interface does not include an MCOL signal. A collision is detected from the receive and transmit
data delimiters. The data signals are 2 bits wide, and a single reference clock must be provided to the
MAC, operating at 50 MHz to sustain the same data rate as MII.
Table 8. EMAC and MDIO Signals for RMII Interface
Signal Name
I/O
Description
RMTXD[1-0]
O
Transmit data (RMTXD). The transmit data pins are a collection of 2 data signals comprising 2 bits
of data. RMTDX0 is the least-significant bit (LSB). The signals are synchronized to the RMII
reference clock and valid only when RMTXEN is asserted.
RMTXEN
O
I
Transmit enable (RMTXEN). The transmit enable signal indicates that the RMTXD pins are
generating nibble data for use by the PHY. It is driven synchronously to the RMII reference clock.
RMCRSDV
Carrier sense/receive data valid (RMCRSDV). The RMCRSDV pin is asserted by the PHY when the
network is not idle in either transmit or receive. The data on RMRXD is considered valid once the
RMCRSDV signal is asserted. The pin is de-asserted when both transmit and receive are idle. The
assertion of this signal is asynchronous to the RMII reference clock.
RMREFCLK
RMRXD[1-0]
I
I
Reference clock (RMREFCLK). A 50-MHz clock must be provided through this pin for RMII
operation.
Receive data (RMRXD). The receive data pins are a collection of 2 data signals comprising 2 bits of
data. RMRDX0 is the least-significant bit (LSB). The signals are synchronized to the RMII reference
clock and valid only when RMCRSDV is asserted. In 10-Mbps operation, RMRXD is sampled every
tenth cycle of the RMII reference clock.
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EMAC Functional Architecture
Table 8. EMAC and MDIO Signals for RMII Interface (continued)
Signal Name
I/O
Description
RMRXER
MDCLK
MDIO
I
Receive error (RMRXER). The receive error signal is asserted for one or more reference clock
periods to indicate that an error was detected in the received frame. This is meaningful only during
data reception when RMCRSDV is active. It is driven synchronously to the RMII reference clock.
O
Management data clock (MDCLK). The MDIO data clock is sourced by the MDIO module on the
system. It is used to synchronize MDIO data access operations done on the MDIO pin. The
frequency of this clock is controlled by the CLKDIV bits in the MDIO control register (CONTROL).
I/O
Management data input output (MDIO). The MDIO pin drives PHY management data into and out of
the PHY by way of an access frame consisting of start of frame, read/write indication, PHY address,
register address, and data bit cycles. The MDIO pin acts as an output for everything except the data
bit cycles, when the pin acts as an input for read operations.
The 50-MHz reference clock (RMREFCLK) for the RMII gasket is sourced externally through a zero-delay
clock buffer. If multiple RMII PHY ports are used, all device RMII reference clocks must come from same
zero-delay clock buffer.
On the TCI6486/C6472 device, RMII pins are multiplexed with other non-RGMII pins. When using the
RMII0 port on EMAC0, there are no restrictions on the available EMAC1 Ethernet interfaces (RMII1,
S3MII1, and RGMII1 are useable). When using the RMII1 port on EMAC1, the EMAC0 Ethernet interfaces
not available due to pin multiplexing are GMII0/MII0. The RMII0, S3MII0, and RGMII0 ports are available
on EMAC0 Ethernet interfaces when using the RMII1 port on EMAC1.
If the device is interfaced to an Ethernet switch through the RMII interface, all device RMII reference
clocks should be externally sourced from the same zero-delay clock buffer.
2.3.3
Gigabit Media Independent Interface (GMII) Connections
Figure 4 shows a device with integrated EMAC and MDIO interfaced to the PHY via a GMII connection.
This interface is available in 10 Mbps, 100 Mbps, and 1000 Mbps modes.
Figure 4. Ethernet Configuration with GMII Interface
MTCLK
GMTCLK
2.5 MHz,
25 MHz,
or 125 MHz
MTXD[7−0]
MTXEN
MCOL
MCRS
Physical
layer
device
(PHY)
System
core
MRCLK
Transformer
RJ−45
MRXD[7−0]
MRXDV
MRXER
MDCLK
MDIO
The GMII interface supports 10/100/1000 Mbps modes. Only full-duplex mode is available in 1000 Mbps
mode. In 10/100 Mbps modes, the GMII interface acts like an MII interface, and only the lower 4 bits of
data are transferred for each of the data buses.
Table 9 summarizes the individual EMAC and MDIO signals for the GMII interface.
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Table 9. EMAC and MDIO Signals for GMII Interface
Signal Name
I/O
Description
MTCLK
I
Transmit clock (MTCLK). The transmit clock is a continuous clock that provides the timing reference
for transmit operations in 10/100 Mbps mode. The MTXD and MTXEN signals are tied to this clock
when in 10/100 Mbps mode. The clock is generated by the PHY and is 2.5 MHz at 10-Mbps
operation, and 25 MHz at 100-Mbps operation.
GMTCLK
MTXD[7-0]
MTXEN
MCOL
O
O
O
I
GMII source synchronous transmit clock (GMTCLK). This clock is used in 1000 Mbps mode only,
providing a continuous 125 MHz frequency for transmit operations. The MTXD and MTXEN signals
are tied to this clock when in Gigabit mode. The clock is generated by the EMAC and is 125 MHz.
Transmit data (MTXD). The transmit data pins are a collection of 8 data signals comprising 8 bits of
data. MTDX0 is the least-significant bit (LSB). The signals are synchronized by MTCLK in 10/100
Mbps mode, and by GMTCLK in Gigabit mode, and valid only when MTXEN is asserted.
Transmit enable (MTXEN). The transmit enable signal indicates that the MTXD pins are generating
nibble data for use by the PHY. It is driven synchronously to MTCLK in 10/100 Mbps mode, and to
GMTCLK in Gigabit mode.
Collision detected (MCOL). The MCOL pin is asserted by the PHY when it detects a collision on the
network. It remains asserted while the collision condition persists. This signal is not necessarily
synchronous to MTCLK nor MRCLK. This pin is used in half-duplex operation only.
MCRS
I
Carrier sense (MCRS). The MCRS pin is asserted by the PHY when the network is not idle in either
transmit or receive. The pin is de-asserted when both transmit and receive are idle. This signal is not
necessarily synchronous to MTCLK nor MRCLK. This pin is used in half-duplex operation only.
MRCLK
I
Receive clock (MRCLK). The receive clock is a continuous clock that provides the timing reference
for receive operations. The MRXD, MRXDV, and MRXER signals are tied to this clock. The clock is
generated by the PHY and is 2.5 MHz at 10-Mbps operation, 25 MHz at 100-Mbps operation and
125 MHz at 1000-Mbps operation.
MRXD[7-0]
I
Receive data (MRXD). The receive data pins are a collection of 8 data signals comprising 8 bits of
data. MRDX0 is the least-significant bit (LSB). The signals are synchronized by MRCLK and valid
only when MRXDV is asserted.
MRXDV
MRXER
I
I
Receive data valid (MRXDV). The receive data valid signal indicates that the MRXD pins are
generating nibble data for use by the EMAC. It is driven synchronously to M RCLK.
Receive error (MRXER). The receive error signal is asserted for one or more MRCLK periods to
indicate that an error was detected in the received frame. This is meaningful only during data
reception when MRXDV is active.
MDCLK
MDIO
O
Management data clock (MDCLK). The MDIO data clock is sourced by the MDIO module on the
system. It is used to synchronize MDIO data access operations done on the MDIO pin. The
frequency of this clock is controlled by the CLKDIV bits in the MDIO control register (CONTROL).
I/O
Management data input output (MDIO). The MDIO pin drives PHY management data into and out of
the PHY by way of an access frame consisting of start of frame, read/write indication, PHY address,
register address, and data bit cycles. The MDIO pin acts as an output for everything except the data
bit cycles, when the pin acts as an input for read operations.
When the TCI6486/C6472 device is interfaced to an Ethernet switch via the GMII interface, the carrier
sense (MCRS) and collision (MCOL) signals are not necessary since full-duplex operation is forced.
On the device, the GMII Ethernet interface is available only on EMAC0 of the device. GMII0 pins are
multiplexed with other non-RGMII pins (RMII1, S3MII1). Due to this multiplexing, when the MII0 interface
is selected on EMAC0, except for RGMII1, no Ethernet interface is available on EMAC1.
2.3.4
Reduced Gigabit Media Independent Interface (RGMII) Connections
Figure 5 shows a TCI6486/C6472 device with integrated EMAC and MDIO interfaced to the PHY via an
RGMII connection. This interface is available in 10 Mbps, 100 Mbps, and 1000 Mbps modes.
22
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Figure 5. Ethernet Configuration with RGMII Interface
RGTXC
RGTXD[3−0]
2.5 MHz
25 MHz,
or 125 MHz
RGTXCTL
RGREFCLK
Physical
layer
device
(PHY)
System
core
RGRXC
Transformer
RJ−45
RGRXD[3−0]
RGRXCTL
RGMDCLK
RGMDIO
The RGMII interface is a reduced pin alternative to the GMII interface. The data paths are reduced, control
signals are multiplexed together, and both edges of the clock are used.
The RGMII interface does not include a MCOL and a MCRS signal for half-duplex mode (only available in
10/100 Mbps mode).
Carrier sense (MCRS) is indicated by one of the following cases instead:
•
•
MRXDV signal (multiplexed in the RGRXCTL signal) is true
MRXDV is false, MRXERR (multiplexed in the RGRXCTL signal) is true, and a value of FFh exists on
the RGRXD[3:0] simultaneously
Table 10 summarizes the individual EMAC and MDIO signals for the RGMII interface.
Table 10. EMAC and MDIO Signals for RGMII Interface
Signal Name
I/O
Description
RGTXC
O
Transmit clock (RGTXC). The transmit clock is a continuous clock that provides the timing reference
for transmit operations. The RGTXD and RGTXCTL signals are tied to this clock. The clock is driven
by the EMAC and is 2.5 MHz at 10-Mbps operation, 25 MHz at 100-Mbps operation, and 125 MHz at
1000-Mbps operation.
RGTXD[3-0]
O
Transmit data (RGTXD). The transmit data pins are a collection of 4 data signals comprising 4 bits of
data. RGTDX0 is the least-significant bit (LSB). The signals are synchronized by RGTXC and valid
only when RGTXCTL is asserted. The lower 4 bits of data are transmitted on the rising edge of the
clock, and the higher 4 bits of data are transmitted on the falling edge of the RGTXC.
RGTXCTL
O
O
Transmit enable (RGTXCTL). The transmit enable signal indicates that the RGTXD pins are
generating nibble data for use by the PHY. It is driven synchronously to RGTXC.
RGREFCLK
Reference clock (RGREFCLK). This 125-MHz reference clock is provided as a convenience. It can
be used as a clock source to the PHY, so that the PHY may generate the RGRXC clock to be sent
to EMAC. This clock is stopped while the device is in reset.
RGRXC
I
I
Receive clock (RGRXC). The receive clock is a continuous clock that provides the timing reference
for receive operations. The RGRXD, and RGRXCTL signals are tied to this clock. The clock is
generated by the PHY and is 2.5 MHz at 10-Mbps operation, 25 MHz at 100-Mbps operation, and
125 MHz at 1000-Mbps operation.
RGRXD[3-0]
Receive data (RGRXD). The receive data pins are a collection of 4 data signals comprising 4 bits of
data. RGRDX0 is the least-significant bit (LSB). The signals are synchronized by RGRXC and valid
only when RGRXCTL is asserted. The lower 4 bits of data are received on the rising edge of the
clock, and the higher 4 bits of data are received on the falling edge of the RGRXC.
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Table 10. EMAC and MDIO Signals for RGMII Interface (continued)
Signal Name
I/O
Description
RGRXCTL
I
Receive control (RGRXCTL). The receive control data has the receive data valid (MRXDV) signal on
the rising edge of the receive clock, and a derivative of receive data valid and receive error
(MRXER) on the falling edge of RGRXC.
When receiving a valid frame with no errors, MRXDV = TRUE is generated as a logic high on the
rising edge on RGRXC and MRXER = FALSE is generated as a logic high on the falling edge of
RGRXC.
When no frame is being received, MRXDV = FALSE is generated as a logic low on the rising edge
of RGRXC and MRXER = FALSE is generated as a logic low on the falling edge of RGRXC.
When receiving a valid frame with errors, MRXDV = TRUE is generated as a logic high on the rising
edge of RGRXC and MRXER = TRUE is generated as a logic low on the falling edge of RGRXC.
RGMDCLK
RGMDIO
O
Management data clock (RGMDCLK). The RGMDIO data clock is sourced by the MDIO module. It
synchronizes MDIO data access operations done on the RGMDIO pin. The frequency of this clock is
controlled by the CLKDIV bits in the MDIO control register (CONTROL).
I/O
Management data input output (RGMDIO). The RGMDIO pin drives PHY management data into and
out of the PHY by way of an access frame consisting of start of frame, read/write indication, PHY
address, register address, and data bit cycles. The RGMDIO pin acts as an output for everything
except the data bit cycles, when the pin acts as an input for read operations.
RGMII pins are not multiplexed with other interfaces and are HSTL I/O having voltages different than other
interfaces. (RGMII pins are 1.5-V/1.8-V HSTL I/O, whereas other interfaces are 3.3-V LVCMOS I/O). The
unused pins of the RGMII PHY should be pulled down to avoid floating inputs.
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EMAC Functional Architecture
2.3.5
Source Synchronous Serial Media Independent Interface (S3MII) Connections
Figure 6 shows a TCI6486/C6472 device with an integrated EMAC and MDIO interface via S3MII
connections connected to a PHY. The S3MII interface supports source synchronous 10-Mbps and
100-Mbps operations with full- and half-duplex support.
Figure 6. Ethernet Configuration with S3MII Interface
125-MHz
125-MHz
zero-delay
XO
clock buffer
MHZ_125_CLK
TX_CLK
TXD
TX_SYNC
Physical
layer
device
(PHY)
RX_CLK
RXD
System
core
RX_SYNC
MDCLK
MDIO
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Table 11 summarizes the individual EMAC and MDIO signals for the S3MII interface.
Table 11. EMAC and MDIO Signals for S3MII Interface
Signal Name
I/O
Description
TX_CLK
O
Transmit clock. The transmit clock is a continuous clock that provides the timing reference for
transmit operations. The TXD and TX_SYNC signals are tied to this clock. This clock is 125 MHz at
10- and 100-Mbps operations.
TX_SYNC
TXD
O
O
I
Transmit Synchronization. The TX_SYNC signal is used to synchronize the TXD data signal. This
signal is synchronized with a 125-MHz clock.
Transmit Data. The transmit data is synchronized with a transmit clock and a transmit
synchronization signal.
RX_CLK
Transmit clock. The transmit clock is a continuous clock that provides the timing reference for
transmit operations. The RXD and RX_SYNC signals are tied to this clock. This clock is 125 MHz at
10- and 100-Mbps operations.
RX_SYNC
RXD
I
I
Receive Synchronization. The RX_SYNC signal is used to synchronize the RXD data signal. This
signal is synchronized with a 125-MHz clock.
Receive Data. The receive data is synchronized with a receive clock and a receive synchronization
signal.
MDCLK
O
Management data clock (MDCLK). The MDIO data clock is sourced by the MDIO module. It
synchronizes MDIO data access operations done on the MDIO pin. The frequency of this clock is
controlled by the CLKDIV bits in the MDIO control register (CONTROL).
MDIO
I/O
Management data input output (MDIO). The MDIO pin drives PHY management data into and out of
the PHY via an access frame consisting of start-of-frame, read/write indication, PHY address,
register address, and data-bit cycles. The MDIO pin acts as an output for everything except the
data-bit cycles, when the pin acts as an input for read operations.
The TCI6486/C6472 device S3MII pins are multiplexed with other non-RGMII pins. When using the
S3MII0 port on EMAC0, there are no restrictions on the available EMAC1 Ethernet interfaces (RMII1,
S3MII1, and RGMII1 are useable). When using the S3MII1 port on EMAC1, the EMAC0 Ethernet
interfaces not available due to pin multiplexing are GMII0/MII0. The RMII0, S3MII0, and RGMII0 ports are
available on EMAC0 Ethernet interfaces.
In a multi-PHY situation, where PHY has only one TX_SYNC for all ports, external logic is needed to
synchronize the TX_SYNC signals from multiple ports or TCI6486/C6472 devices. The TXD signal from
the multiple ports should also be synchronized using external logic since the clock-phase relation of
configuration for S3MII.
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EMAC Functional Architecture
Figure 7. S3MII Multi-PHY Configuration
S3MII
multi-PHY
TX_CLK
TX_SYNC
Device #1
TXD
P0_TXD
P0_RXD
TX_SYNC
TX_CLK
RXD
RX_SYNC
RX_CLK
MHZ_125_CLK
Device #2
TXD
TX_SYNC
TX_CLK
P1_TXD
P1_RXD
External
logic
element
RXD
RX_SYNC
RX_CLK
MHZ_125_CLK
Device #n
TXD
TX_SYNC
TX_CLK
Pn_TXD
Pn_RXD
RXD
RX_SYNC
RX_CLK
MHZ_125_CLK
Low-skew
buffer
RX_SYNC
RX_CLK
125-MHz
zero-delay
clock buffer
125-MHz
XO
Zero-delay
clock buffer
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In the case of the S3MII switch, where the switch has only one TX_SYNC for all ports, external logic is
needed to synchronize the TX_SYNC signals from multiple ports or TCI6486/C6472 devices. The TXD
signal from the multiple ports should also be synchronized using external logic since the clock-phase
mutli-PHY configuration for S3MII.
Figure 8. S3MII Switch Configuration
S3MII
switch
TX_CLK
TX_SYNC
Device #1
TXD
TX_SYNC
TX_CLK
P0_TXD
P0_RXD
RXD
RX_SYNC
RX_CLK
MHZ_125_CLK
Device #2
TXD
TX_SYNC
TX_CLK
P1_TXD
P1_RXD
External
logic
element
RXD
RX_SYNC
RX_CLK
MHZ_125_CLK
Device #n
TXD
TX_SYNC
TX_CLK
Pn_TXD
Pn_RXD
RXD
RX_SYNC
RX_CLK
MHZ_125_CLK
Low-skew
buffer
RX_SYNC
RX_CLK
125-MHz
zero-delay
clock buffer
125-MHz
XO
Zero-delay
clock buffer
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EMAC Functional Architecture
2.4 Ethernet Protocol Overview
Ethernet provides a reliable, connectionless service to a networking application. A brief overview of the
ethernet protocol follows. For more information on the carrier sense multiple access with collision
detection (CSMA/CD) access method (ethernet's multiple access protocol), see the IEEE 802.3 standard
document.
2.4.1
Ethernet Frame Format
All the ethernet technologies use the same frame structure. The format of an ethernet frame is shown in
Figure 9 and described in Table 12. The ethernet packet is the collection of bytes representing the data
The ethernet frames are of variable lengths, with no frame smaller than 64 bytes or larger than
RXMAXLEN bytes (header, data, and CRC).
Figure 9. Ethernet Frame
Number of bytes
7
1
6
6
2
46 − (RXMAXLEN - 18)
Data
4
Preamble
SFD
Destination
Source
Len
FCS
Legend: SFD = Start Frame Delimiter; FCS = Frame Check Sequence (CRC)
Table 12. Ethernet Frame Description
Field
Bytes
Description
Preamble
7
These 7 bytes have a fixed value of 55h. They wake up the receiving EMAC ports and
synchronize their clocks to that of the sender's clock.
Start-of-Frame
Delimiter
1
6
This field with a value of 5Dh immediately follows the preamble pattern and indicates
the start of important data.
Destination
address
This field contains the Ethernet MAC address of the intended EMAC port for the frame.
It may be an individual or multicast (including broadcast) address. If the destination
EMAC port receives an Ethernet frame with a destination address that does not match
any of its MAC physical addresses, and no promiscuous, multicast or broadcast
channel is enabled, it discards the frame.
Source
address
6
2
This field contains the MAC address of the Ethernet port that transmits the frame to the
Local Area Network.
Len
The length field indicates the number of EMAC client data bytes contained in the
subsequent data field of the frame. This field can also be used to identify the data type
carried by the frame.
Data
46 to (RXMAXLEN - 18) This field carries the datagram containing the upper layer protocol frame (the IP layer
datagram). The maximum transfer unit (MTU) of Ethernet is (RXMAXLEN - 18) bytes.
Therefore, if the upper layer protocol datagram exceeds (RXMAXLEN - 18) bytes, the
host must fragment the datagram and send it in multiple Ethernet packets. The
minimum size of the data field is 46 bytes. Thus, if the upper layer datagram is less
then 46 bytes, the data field must be extended to 46 bytes by appending extra bits after
the data field, but prior to calculating and appending the FCS.
Frame Check
Sequence
4
A cyclic redundancy check (CRC) is used by the transmit and receive algorithms to
generate a CRC value for the FCS field. The frame check sequence covers the 60 to
(RXMAXLEN - 4) bytes of the packet data. Note that the 4-byte FCS field may not be
included as part of the packet data, depending on the EMAC configuration.
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2.4.2
Multiple Access Protocol
Nodes in an ethernet local area network are interconnected by a broadcast channel. As a result, when an
EMAC port transmits a frame, all of the adapters on the local network receive the frame. Carrier sense
multiple access with collision detection (CSMA/CD) algorithms are used when the EMAC operates in
half-duplex mode. When operating in full-duplex mode, there is no contention for use of a shared medium,
because there are exactly two ports on the local network.
Each port runs the CSMA/CD protocol without explicit coordination with the other ports on the ethernet
network.
Within a specific port, the CSMA/CD protocol is as follows:
1. The port obtains data from upper layer protocols at its node, prepares an ethernet frame, and puts the
frame in a buffer.
2. If the port senses that the medium is idle, it starts to transmit the frame. If the port senses that the
transmission medium is busy, it waits until it senses no signal energy (plus an inter-packet gap time)
and then starts to transmit the frame.
3. While transmitting, the port monitors for the presence of signal energy coming from other ports. If the
port transmits the entire frame without detecting signal energy from other ethernet devices, the port is
finished with the frame.
4. If the port detects signal energy from other ports while transmitting, it stops transmitting its frame and
instead transmits a 48-bit jam signal.
5. After transmitting the jam signal, the port enters an exponential back off phase. Specifically, when
transmitting a given frame, after experiencing a number of collisions in a row for the frame, the port
chooses a random value that is dependent on the number of collisions. The port then waits an amount
of time which is multiple of this random value, and returns to Step 1.
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EMAC Functional Architecture
2.5 Programming Interface
2.5.1
Packet Buffer Descriptors
The buffer descriptor is a central part of the EMAC module. It determines how the application software
describes ethernet packets to be sent and empty buffers to be filled with incoming packet data.
Figure 10. Basic Descriptor Format
Word Offset
Bit Fields
31
16 15
0
0
1
2
3
Next Descriptor Pointer
Buffer Pointer
Buffer Offset
Flags
Buffer Length
Packet Length
Table 13. Basic Descriptors
Word
Offset Field
Field Description
0
Next Descriptor
Pointer
The next descriptor pointer creates a single linked list of descriptors. Each descriptor describes a
packet or a packet fragment. When a descriptor points to a single buffer packet or the first fragment
of a packet, the start-of-packet (SOP) flag is set in the flags field. When a descriptor points to a
single buffer packet or the last fragment of a packet, the end-of-packet (EOP) flag is set. When a
packet is fragmented, each fragment must have its own descriptor and appear sequentially in the
descriptor linked list.
1
2
2
3
Buffer Pointer
Buffer Offset
Buffer Length
Flags
The buffer pointer refers to the memory buffer that either contains packet data during transmit
operations, or is an empty buffer ready to receive packet data during receive operations.
The buffer offset is the offset from the start of the packet buffer to the first byte of valid data. This
field only has meaning when the buffer descriptor points to a buffer that contains data.
The buffer length is the number of valid packet data bytes stored in the buffer. If the buffer is empty
and waiting to receive data, this field represents the size of the empty buffer.
The flags field contains more information about the buffer, such as whether it is the first fragment in
a packet (SOP), the last fragment in a packet (EOP), or contains an entire contiguous Ethernet
3
Packet Length
The packet length only has meaning for buffers that both contain data and are the start of a new
packet (SOP). For SOP descriptors, the packet length field contains the length of the entire Ethernet
packet, even if it is contained in a single buffer or fragmented over several buffers.
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For example, consider three packets to be transmitted, Packet A is a single fragment (60 bytes), Packet B
is fragmented over three buffers (1514 bytes total), and Packet C is a single fragment (1514 bytes).
Figure 11 shows the linked list of descriptors to describe these three packets.
Figure 11. Typical Descriptor Linked List
pNext
pBuffer
Packet A
60 bytes
0
60
60
SOP | EOP
pNext
Packet B
Fragment 1
512 bytes
pBuffer
0
512
SOP
1514
pNext
Packet B
Fragment 2
502 bytes
pBuffer
0
502
−−−
−−−
pNext
Packet B
Fragment 3
500 bytes
pBuffer
0
500
−−−
EOP
pNext (NULL)
pBuffer
Packet C
1514 bytes
0
1514
1514
SOP | EOP
2.5.2
Transmit and Receive Descriptor Queues
The EMAC module processes descriptors in linked list chains (Section 2.5.1). The lists controlled by the
EMAC are maintained by the application software through the head descriptor pointer (HDP) registers.
Since the EMAC supports eight channels for both transmit and receive, there are eight head descriptor
pointer registers for both.
They are designated as follows:
•
•
TXnHDP: Transmit Channel n DMA Head Descriptor Pointer Register
RXnHDP: Receive Channel n DMA Head Descriptor Pointer Register
After an EMAC reset, and before enabling the EMAC for send or receive, you must initialize all 16 head
descriptor pointer registers to zero.
The EMAC uses a simple system to determine ownership of a descriptor (either the EMAC or the
application software). There is a flag in the descriptor flags field called OWNER. When this flag is set, the
EMAC owns the referenced packet.
NOTE: Ownership is assigned on a packet-based granularity, not on descriptor granularity. Thus,
only SOP descriptors use the OWNER flag. The EMAC patches the SOP descriptor of the
corresponding packet and clears the OWNER flag as packets are processed. This means
that the EMAC is finished processing all descriptors up to and including the first with the
EOP flag set. This indicates that you have reached the end of the packet. This may only be
one descriptor with both the SOP and EOP flags set.
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EMAC Functional Architecture
To add a descriptor or a linked list of descriptors to an EMAC descriptor queue for the first time, the
software application writes the pointer to the descriptor or first descriptor of a list to the corresponding
HDP register. Note that the last descriptor in the list must have its next pointer cleared so that the EMAC
can detect the end of the list. If only a single descriptor is added, its next descriptor pointer must be
initialized to zero.
The HDP register must never be written to a second time while a previous list is active. To add additional
descriptors to a descriptor list already owned by the EMAC, the NULL next pointer of the last descriptor of
the previous list is patched with a pointer to the first descriptor in the new list. The list of new descriptors
to be appended to the existing list must itself be NULL terminated before the pointer patch is performed.
If the EMAC reads the next pointer of a descriptor as NULL in the instant before an application appends
additional descriptors to the list by patching the pointer, this may result in a race condition. Thus, the
software application must always examine the Flags field of all EOP packets, looking for a special flag
called end-of-queue (EOQ). The EOQ flag is set by the EMAC on the last descriptor of a packet when the
descriptor's next pointer is NULL, allowing the EMAC to indicate to the software application that it has
reached the end of the list. When the software application sees the EOQ flag set, and there are more
descriptors to process, the application may then submit the new list or missed list portion by writing the
new list pointer to the same HDP register that started the process.
This process applies when adding packets to a transmit list, and empty buffers to a receive list.
2.5.3
Transmit and Receive EMAC Interrupts
The EMAC synchronizes the descriptor list processing by using interrupts to the software application. The
interrupts are controlled by the application by using the interrupt masks, global interrupt enable, and the
completion pointer register (CP). This register is also called interrupt acknowledge register.
As the EMAC supports eight channels for both transmit and receive, there are eight CP registers for both.
They are designated as:
•
TXnCP: Transmit Channel n Completion Pointer (Interrupt Acknowledge) Register
•
RXnCP: Receive Channel n Completion Pointer (Interrupt Acknowledge) Register
These registers serve two purposes. When read, they return the pointer to the last descriptor that the
EMAC has processed. When written by the software application, the value represents the last descriptor
processed by the software application. If these two values do not match, the interrupt is active.
The system configuration determines whether an active interrupt can interrupt the CPU. In general, the
global interrupt for EMAC and MDIO must be enabled in the EMIC module, and it also must be mapped in
the DSP interrupt controller and enabled as a CPU interrupt. If the system is configured properly, the
interrupt for a specific receive or transmit channel executes under these conditions when the
corresponding interrupt is enabled in the EMAC using the RXINTMASKSET or TXINTMASKSET registers.
The current state of the receive or transmit channel interrupt can be examined directly by the software
application by reading the RXINTSTATRAW and TXINTSTATRAW registers, whether or not the interrupt
is enabled.
Interrupts are acknowledged when the application software updates the value of TXnCP or RXnCP with a
value that matches the internal value kept by the EMAC.
This mechanism ensures that the application software never misses an EMAC interrupt, as the interrupt
and its acknowledgment are tied directly to the actual buffer descriptors processing.
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2.5.4
Transmit Buffer Descriptor Format
A transmit (TX) buffer descriptor (Figure 12) is a contiguous block of four 32-bit data words aligned on a
32-bit boundary that describes a packet or a packet fragment.
Example 1 shows the transmit buffer descriptor described by a C structure.
Figure 12. Transmit Descriptor Format
(a) Word 0
31
0
Next Descriptor Pointer
(b) Word 1
31
0
0
Buffer Pointer
(c) Word 2
31
16
15
Buffer Offset
Buffer Length
(d) Word 3
31
30
29
28
27
26
25
16
0
TDOWN PASS
CMPLT
SOP
15
EOP OWNER EOQ
Reserved
CRC
Packet Length
Example 1. Transmit Descriptor in C Structure Format
/*
// EMAC Descriptor
//
// The following is the format of a single buffer descriptor
// on the EMAC.
*/
typedef struct _EMAC_Desc {
struct _EMAC_Desc *pNext;
/* Pointer to next descriptor in chain */
*pBuffer; /* Pointer to data buffer */
BufOffLen; /* Buffer Offset(MSW) and Length(LSW) */
PktFlgLen; /* Packet Flags(MSW) and Length(LSW) */
Uint8
Uint32
Uint32
} EMAC_Desc;
/* Packet Flags */
#define EMAC_DSC_FLAG_SOP
#define EMAC_DSC_FLAG_EOP
#define EMAC_DSC_FLAG_OWNER
#define EMAC_DSC_FLAG_EOQ
#define EMAC_DSC_FLAG_TDOWNCMPLT
#define EMAC_DSC_FLAG_PASSCRC
0x80000000u
0x40000000u
0x20000000u
0x10000000u
0x08000000u
0x04000000u
34
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EMAC Functional Architecture
2.5.4.1
Next Descriptor Pointer
The next descriptor pointer indicates the 32-bit word aligned memory address of the next buffer descriptor
in the transmit queue. The pointer creates a linked list of buffer descriptors. If the value of this pointer is
zero, then the current buffer is the last buffer in the queue. The software application must set this value
prior to adding the descriptor to the active transmit list. The pointer is not altered by the EMAC.
The value of pNext should never be altered once the descriptor is in an active transmit queue, unless its
current value is NULL. If the pNext pointer is initially NULL, and more packets need to be queued for
transmit, the software application may alter this pointer to point to a newly appended descriptor. The
EMAC will use the new pointer value and proceed to the next descriptor unless the pNext value has
already been read. If the pNext value has already been read, the transmitter will halt on the specified
transmit channel, and the software application may restart it then. The software can detect this issue by
searching for an end-of-queue (EOQ) condition flag on the updated packet descriptor when it is returned
by the EMAC.
2.5.4.2
Buffer Pointer
The buffer pointer is the byte-aligned memory address of the memory buffer associated with the buffer
descriptor. The software application must set this value prior to adding the descriptor to the active transmit
list. This pointer is not altered by the EMAC.
2.5.4.3
Buffer Offset
This 16-bit field indicates how many unused bytes are at the start of the buffer. For example, a value of
0000h indicates that no unused bytes are at the start of the buffer and that valid data begins on the first
byte of the buffer. A value of 000Fh indicates that the first 15 bytes of the buffer are to be ignored by the
EMAC and that valid buffer data starts on byte 16 of the buffer. The software application must set this
value prior to adding the descriptor to the active transmit list. This field is not altered by the EMAC.
Note that this value is only checked on the first descriptor of a given packet (where the SOP flag is set). It
cannot specify the offset of subsequent packet fragments. Also, as the buffer pointer may point to any
byte-aligned address, this field may be unnecessary, depending on the device driver architecture.
The range of legal values for this field is 0 to (Buffer Length - 1).
2.5.4.4
2.5.4.5
2.5.4.6
Buffer Length
This 16-bit field indicates how many valid data bytes are in the buffer. On single fragment packets, this
value is also the total length of the packet data to be transmitted. If the buffer offset field is used, the offset
bytes are not counted as part of this length. This length counts only valid data bytes. The software
application must set this value prior to adding the descriptor to the active transmit list. This field is not
altered by the EMAC.
Packet Length
This 16-bit field specifies the number of data bytes in the entire packet. Any leading buffer offset bytes are
not included. The sum of the buffer length fields of each of the packet's fragments (if more than one) must
be equal to the packet length. The software application must set this value prior to adding the descriptor to
the active transmit list. This field is not altered by the EMAC. This value is only checked on the first
descriptor of a given packet, where the SOP flag is set.
Start-of-Packet (SOP) Flag
When set, this flag indicates that the descriptor points to a packet buffer that is the start of a new packet.
For a single fragment packet, both the SOP and end-of-packet (EOP) flags are set. Otherwise, the
descriptor pointing to the last packet buffer for the packet sets the EOP flag. This bit is set by the software
application and is not altered by the EMAC.
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2.5.4.7
End-of-Packet (EOP) Flag
When set, this flag indicates that the descriptor points to the last packet buffer for a given packet. For a
single fragment packet, both the start-of-packet (SOP) and EOP flags are set. Otherwise, the descriptor
pointing to the last packet buffer for the packet sets the EOP flag. This bit is set by the software
application and is not altered by the EMAC.
2.5.4.8
Ownership (OWNER) Flag
When set, this flag indicates that all the descriptors for the given packet (from SOP to EOP) are currently
owned by the EMAC. This flag is set by the software application on the SOP packet descriptor before
adding the descriptor to the transmit descriptor queue. For a single fragment packet, the SOP, EOP, and
OWNER flags are all set. The OWNER flag is cleared by the EMAC once it is finished with all the
descriptors for the given packet. Note that this flag is valid on SOP descriptors only.
2.5.4.9
End-of-Queue (EOQ) Flag
When set, this flag indicates that the descriptor in question was the last descriptor in the transmit queue
for a given transmit channel, and that the transmitter has halted. This flag is initially cleared by the
software application prior to adding the descriptor to the transmit queue. This bit is set by the EMAC when
the EMAC identifies that a descriptor is the last for a given packet (the EOP flag is set), and there are no
more descriptors in the transmit list (next descriptor pointer is NULL).
The software application can use this bit to detect when the EMAC transmitter for the corresponding
channel has halted. This is useful when the application appends additional packet descriptors to a transmit
queue list that is already owned by the EMAC. Note that this flag is valid on EOP descriptors only.
2.5.4.10 Teardown Complete (TDOWNCMPLT) Flag
This flag is used when a transmit queue is being torn down, or aborted, instead of allowing transmission,
such as during device driver reset or shutdown conditions. The EMAC sets this bit in the SOP descriptor
of each packet as it is aborted from transmission.
Note that this flag is valid on SOP descriptors only. Also note that only the first packet in an unsent list has
the TDOWNCMPLT flag set. The EMAC does not process subsequent descriptors.
2.5.4.11 Pass CRC (PASSCRC) Flag
The software application sets this flag in the SOP packet descriptor before it adds the descriptor to the
transmit queue. Setting this bit indicates to the EMAC that the 4-byte Ethernet CRC is already present in
the packet data, and that the EMAC should not generate its own version of the CRC.
When the CRC flag is cleared, the EMAC generates and appends the 4-byte CRC. The buffer length and
packet length fields do not include the CRC bytes. When the CRC flag is set, the 4-byte CRC is supplied
by the software application and is appended to the end of the packet data. The buffer length and packet
length fields include the CRC bytes, as they are part of the valid packet data. Note that this flag is valid on
SOP descriptors only.
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EMAC Functional Architecture
2.5.5
Receive Buffer Descriptor Format
A receive (RX) buffer descriptor (Figure 13) is a contiguous block of four 32-bit data words aligned on a
32-bit boundary that describes a packet or a packet fragment.
Example 2 shows the receive descriptor described by a C structure.
Figure 13. Receive Descriptor Format
(a) Word 0
31
0
0
0
Next Descriptor Pointer
Buffer Pointer
(b) Word 1
31
(c) Word 2
31
16
15
Buffer Offset
Buffer Length
(d) Word 3
31
SOP
30
EOP
29
28
EOQ
20
27
26
25
JABBER
17
24
OWNER
21
TDOWNCMPLT
19
PASSCRC
18
OVERSIZE
23
22
16
NOMATCH
0
FRAGMENT
15
UNDERSIZED
CONTROL
OVERRUN
CODEERROR
ALIGNERROR
CRCERROR
Packet Length
Example 2. Receive Descriptor in C Structure Format
/*
// EMAC Descriptor
//
// The following is the format of a single buffer descriptor
// on the EMAC.
*/
typedef struct _EMAC_Desc {
struct _EMAC_Desc *pNext;
/* Pointer to next descriptor in chain */
*pBuffer; /* Pointer to data buffer */
BufOffLen; /* Buffer Offset(MSW) and Length(LSW) */
PktFlgLen; /* Packet Flags(MSW) and Length(LSW) */
Uint8
Uint32
Uint32
} EMAC_Desc;
/* Packet Flags */
#define EMAC_DSC_FLAG_SOP
#define EMAC_DSC_FLAG_EOP
#define EMAC_DSC_FLAG_OWNER
#define EMAC_DSC_FLAG_EOQ
#define EMAC_DSC_FLAG_TDOWNCMPLT
#define EMAC_DSC_FLAG_PASSCRC
#define EMAC_DSC_FLAG_JABBER
#define EMAC_DSC_FLAG_OVERSIZE
#define EMAC_DSC_FLAG_FRAGMENT
#define EMAC_DSC_FLAG_UNDERSIZED
#define EMAC_DSC_FLAG_CONTROL
#define EMAC_DSC_FLAG_OVERRUN
#define EMAC_DSC_FLAG_CODEERROR
#define EMAC_DSC_FLAG_ALIGNERROR
#define EMAC_DSC_FLAG_CRCERROR
#define EMAC_DSC_FLAG_NOMATCH
0x80000000u
0x40000000u
0x20000000u
0x10000000u
0x08000000u
0x04000000u
0x02000000u
0x01000000u
0x00800000u
0x00400000u
0x00200000u
0x00100000u
0x00080000u
0x00040000u
0x00020000u
0x00010000u
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2.5.5.1
Next Descriptor Pointer
The next descriptor pointer indicates the 32-bit word aligned memory address of the next buffer descriptor
in the receive queue. The pointer creates a linked list of buffer descriptors. If the value of the pointer is
zero, then the current buffer is the last buffer in the queue. The software application must set this value
prior to adding the descriptor to the active receive list. This pointer is not altered by the EMAC.
The value of pNext should never be altered once the descriptor is in an active receive queue, unless its
current value is NULL. If the pNext pointer is initially NULL, and more empty buffers can be added to the
pool, the software application may alter this pointer to indicate a newly appended descriptor. The EMAC
will use the new pointer value and proceed to the next descriptor unless the pNext value has already been
read. If the pNext value has already been read, the receiver will halt the receive channel in question, and
the software application may restart it at that time. The software can detect this case by searching for an
end-of-queue (EOQ) condition flag on the updated packet descriptor when it is returned by the EMAC.
2.5.5.2
Buffer Pointer
The buffer pointer is the byte-aligned memory address of the memory buffer associated with the buffer
descriptor. The software application must set this value prior to adding the descriptor to the active receive
list. This pointer is not altered by the EMAC.
2.5.5.3
Buffer Offset
This 16-bit field must be initialized to zero by the software application before adding the descriptor to a
receive queue.
This field will be updated depending on the RXBUFFEROFFSET register setting. When the offset register
is set to a non-zero value, the received packet is written to the packet buffer at an offset given by the
value of the register, and this value is also written to the buffer offset field of the descriptor.
When a packet is fragmented over multiple buffers because it does not fit in the first buffer supplied, the
buffer offset only applies to the first buffer in the list, which is where the start-of-packet (SOP) flag is set in
the corresponding buffer descriptor. In other words, the buffer offset field is only updated by the EMAC on
SOP descriptors.
The range of legal values for the BUFFEROFFSET register is 0 to (Buffer Length - 1) for the smallest
value of buffer length for all descriptors in the list.
2.5.5.4
Buffer Length
This 16-bit field has two functions:
•
Before the descriptor is first placed on the receive queue by the application software, the software
initializes the buffer length field with the physical size of the empty data buffer specified by the buffer
pointer field.
•
After the empty buffer has been processed by the EMAC and filled with received data bytes, the EMAC
updates the buffer length field to reflect the actual number of valid data bytes written to the buffer.
2.5.5.5
Packet Length
This 16-bit field specifies the number of data bytes in the entire packet. The software application initializes
this value to zero for empty packet buffers. The EMAC fills in the value on the first buffer used for a given
packet, as signified by the EMAC setting a start-of-packet (SOP) flag. The EMAC sets the packet length
on all SOP buffer descriptors.
2.5.5.6
Start-of-Packet (SOP) Flag
When set, this flag indicates that the descriptor points to the starting packet buffer of a new packet. For a
single fragment packet, both the SOP and end-of-packet (EOP) flags are set. Otherwise, the descriptor
pointing to the last packet buffer for the packet has the EOP flag set. The software application initially
clears this flag before adding the descriptor to the receive queue. The EMAC sets this bit on SOP
descriptors.
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EMAC Functional Architecture
2.5.5.7
End-of-Packet (EOP) Flag
When set, this flag indicates that the descriptor points to the last packet buffer for a given packet. For a
single fragment packet, both the start-of-packet (SOP) and EOP flags are set. Otherwise, the descriptor
pointing to the last packet buffer for the packet has the EOP flag set. The software application initially
clears this flag before adding the descriptor to the receive queue. The EMAC sets this bit on EOP
descriptors.
2.5.5.8
Ownership (OWNER) Flag
When set, this flag indicates that the descriptor is currently owned by the EMAC. The software application
sets this flag before adding the descriptor to the receive descriptor queue. The EMAC clears this flag once
it is finished with a given set of descriptors associated with a received packet. The EMAC updates the flag
on SOP descriptor only. If the application identifies that the OWNER flag is cleared on an SOP descriptor,
it may assume that the EMAC has released all descriptors up to and including the first with the EOP flag
set. Note that for single buffer packets, the same descriptor will have both the SOP and EOP flags set.
2.5.5.9
End-of-Queue (EOQ) Flag
When set, this flag indicates that the specified descriptor was the last descriptor in the receive queue for a
given receive channel, and that the corresponding receiver channel has halted. The software application
initially clears this flag prior to adding the descriptor to the receive queue. The EMAC sets this bit when
the EMAC identifies that a descriptor is the last for a given packet received (it also sets the EOP flag), and
there are no more descriptors in the receive list (the next descriptor pointer is NULL).
The software application uses this bit to detect when the EMAC receiver for the corresponding channel
has halted. This is useful when the application appends additional free buffer descriptors to an active
receive queue. Note that this flag is valid on EOP descriptors only.
2.5.5.10 Teardown Complete (TDOWNCMPLT) Flag
This flag is used when a receive queue is being torn down, or aborted, instead of being filled with received
data, such as during device driver reset or shutdown conditions. The EMAC sets this bit in the descriptor
of the first free buffer when the teardown occurs. No additional queue processing is performed.
2.5.5.11 Pass CRC (PASSCRC) Flag
The EMAC sets this flag in the SOP buffer descriptor, if the received packet includes the 4-byte CRC. The
software application must clear this flag before submitting the descriptor to the receive queue.
2.5.5.12 Jabber Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet is a jabber frame and was not
discarded because the RXCEFEN bit was set in the RXMBPENABLE register.
2.5.5.13 Oversize Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet is an oversized frame and was
not discarded because the RXCEFEN bit was set in the RXMBPENABLE register.
2.5.5.14 Fragment Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet is only a packet fragment and
was not discarded because the RXCEFEN bit was set in the RXMBPENABLE register.
2.5.5.15 Undersized Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet is undersized and was not
discarded because the RXCSFEN bit was set in the RXMBPENABLE register.
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2.5.5.16 Control Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet is an EMAC control frame and
was not discarded because the RXCMFEN bit was set in the RXMBPENABLE register.
2.5.5.17 Overrun Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet was aborted due to a receive
overrun.
2.5.5.18 Code Error (CODEERROR) Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet contained a code error and
was not discarded because the RXCEFEN bit was set in the RXMBPENABLE register.
2.5.5.19 Alignment Error (ALIGNERROR) Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet contained an alignment error
and was not discarded because the RXCEFEN bit was set in the RXMBPENABLE register.
2.5.5.20 CRC Error (CRCERROR) Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet contained a CRC error and
was not discarded because the RXCEFEN bit was set in the RXMBPENABLE register.
2.5.5.21 No-Match (NOMATCH) Flag
The EMAC sets this flag in the SOP buffer descriptor if the received packet did not pass any of the
EMAC's address match criteria and was not discarded because the RXCAFEN bit was set in the
RXMBPENABLE register. Although the packet is a valid Ethernet data packet, it is only received because
the EMAC is in promiscuous mode.
2.6 Communications Port Programming Interface (CPPI)
The CPPI refers to the data structures used by the EMAC to describe transmit and receive packets and
the application programming interface to manipulate the data structures. The CPPI maximizes the
efficiency of communication between host processor and EMAC. It minimizes the host interaction,
maximizes the memory use efficiency, and maximizes the symmetry between transmit and receive
operations. Some of the important features of the CPPI include distributed buffer management, protocol
independent packet level interface, support for multichannel/multi-priority queuing, and support for multiple
buffer queues. The details of transmit and receive operations and buffer descriptors are covered in
2.7 Ethernet Multicore Interrupt Combiner (EMIC) Module
The ethernet multicore interrupt combiner (EMIC) module is designed to efficiently route a single set of
interrupts from EMAC and MDIO to multiple cores on a multicore device. It also incorporates interrupt
pacing functionality for the Ethernet TX and RX pulse interrupts. The EMIC module uses the pulse
interrupts to incorporate some of its pacing functionality.
Figure 14, make up the EMIC:
•
•
•
Pacer Block which consists of:
–
–
Timed-Delay state machine (TSM)
Divide State Machine (DSM)
Transmit Pacer and Interrupt Combiner (TPIC) which consists of:
–
–
Pacer block per TX event
Interrupt combiner
Receive Pacer and Interrupt Combiner (RPIC) which consists of:
Pacer block per TX event
–
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EMAC Functional Architecture
–
Interrupt combiner
•
•
•
•
Common Interrupt Combiner (CIC)
Prescaler
Registers
CFG peripheral bus interface
Figure 14. EMIC Block Diagram
TX pacer and interrupt combiner
RX pacer and interrupt combiner
Common interrupt combiner
TX pacer and interrupt combiner
RX pacer and interrupt combiner
Common interrupt combiner
TX pacer and interrupt combiner
RX pacer and interrupt combiner
Common interrupt combiner
TX pacer and interrupt combiner
RX pacer and interrupt combiner
Common interrupt combiner
TX pacer and interrupt combiner
RX pacer and interrupt combiner
Common interrupt combiner
TX pacer and interrupt combiner
RX pacer and interrupt combiner
Common interrupt combiner
Registers
MACTXINT0
MACRXINT0
MACINT0
To GEM0
To GEM1
To GEM2
To GEM3
To GEM4
To GEM5
EMAC
interrupts (18)
MACTXINT1
MACRXINT1
MACINT1
MACTXINT2
MACRXINT2
MACINT2
MDIO
interrupts (2)
MACTXINT3
MACRXINT3
MACINT3
Peripheral bus
reset
MACTXINT4
MACRXINT4
MACINT4
Peripheral bus
MACTXINT5
MACRXINT5
MACINT5
PS_TICK
Peripheral bus
clock
Prescaler
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2.7.1
Pacing Block
In simple terms, interrupt pacing represents delaying the initial EMAC events to CPU interrupt based on
certain criteria. The pacing block is the basic building block for the interrupt pacing operation. One of the
motivations for interrupt pacing is that during Ethernet operation, hundreds or thousands of interrupts are
generated per second for packets transmitted or received and interrupt pacing relieves the CPU of the
burden of processing every single interrupt. This block provides time-based or count-based pacing of
interrupts, in any combination. In addition, this block supports reprogramming of timer value and count
value without hardware/software race condition and also facilitates use of the same timer and count
values for the next event period.
The EVT_IN is the pulse interrupt from EMAC. This is forwarded to timed-delay and divide by N state
is the clock tick from the prescalar block. The prescaler block forwards this signal to all the pacing blocks.
Figure 15. Pacing Block
Pacing block
PS_TICK
EVT_IN
EVT_TIMED
Timed-
delay SM
EVT_OUT
Divide SM
EVT_DIV
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EMAC Functional Architecture
2.7.2
Timed Delay State Machine (TDSM)
The timed-delay state machine fully implements the functionality of the time-delay based interrupt pacing.
The TIME_CFG bit field of the TPCFG and RPCFG registers (described in Section 3) is set to 0 on reset
and disables this state machine. When the TIME_CFG is set to a non-zero value, an output pulse is
generated after the TIME_CFG number of prescalar output periods. The counter starts counting on the
first event.
The state machine has three states, WAITING, DELAY, and OUTPUT. Upon reset, the state machine is
placed in the WAITING state. The state machine makes transitions between the states as shown in
Figure 16. Note that states that are grayed out are transitional states, in the sense that the SM does not
stay in the grayed state. While in the transitional state, it typically does an operation, like incrementing the
TIME or resetting the TIME. It then changes the state to the state illustrated by the dotted line.
Figure 16. TDSM State Transition Diagram
EVT_PULSE = 0 (or)
EVT_PULSE = 1 && TIME >= TIME_CFG
Waiting
Time=0
Time=0
PS_TICK=0 &&
DIV_NEXT=0
Delay
Increment
time
PS_TICK=1 &&
TIME < TIME_CFG
&& DIV_NEXT=0
Time=0
Time=0
EVT
_PU
TIME
LSE=1
< TIM
E_C
&&
FG
Output
Time=0
EVT_PULSE=0 (or)
EVT_PULSE=1 && TIME >= TIME_CFG
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2.7.3
Divide-by-N State Machine (DSM)
The divide-by-N state machine fully implements the functionality of the count-based interrupt pacing. The
CNT_CFG bit field of the TPCFG and RPCFG registers (described in Section 3) is set to 0 on reset and
immediately generates a pulse (basically means a zero delay), when the TIME_CFG is also set to 0 (i.e.,
timed-delay SM is disabled). When the TIME_CFG is set to non-zero, it then disables the divide-by-N
state machine. When the CNT_CFG is set to non-zero, the CNT_CFG number of events are counted
before an output pulse is generated. The counter resets (and reloads) every time when a divide-by-N
pulse is generated.
The state machine has three states, WAITING, COUNT, and OUTPUT. Upon reset, the state machine is
placed in the WAITING state. The state machine makes transitions between the states as shown in
Figure 17. Note that states that are grayed out are transitional states, in the sense that the SM does not
stay in the grayed state. While in the transitional state, it typically does an operation, like setting the
counter to a certain value.
Figure 17. DSM State Transition Diagram
EVT_PULSE=0 (or) EVT_PULSE=1 &&
CNT >= CNT_CFG && TIME_CFG I=0
Waiting
Increment
CNT
EVT_PULSE=0
&& CR=0
CNT=1
Count
CNT=1
EVT_PULSE=1 &&
CR=1 && CNT <
CNT_CFG
CNT >= CNT_CFG
&& EVT_PULSE=1
NEXT_
DIV=1
CNT=1
Output
NEXT_
DIV=1
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EMAC Functional Architecture
2.7.4
Transmit Pacer and Interrupt Combiner (TPIC)
The transmit pacer and interrupt combiner (TPIC) block performs the following functions:
•
•
Optionally implements pacing for transmit events.
Combines the output of the pacer module based on the settings of the bits 8 to 15 in the EW_INTCTL
register and generates a single MACTXINT interrupt per the C64x+ megamodule.
•
•
Receives a single PS_TICK and forwards it to all the pacing blocks.
Allows, per interrupt enabling or disabling of the interrupts, the setting of bits 8 to 15 in the
EW_INTCTL register.
Figure 18 shows the block diagram of transmit pacer and interrupt combiner (TPIC). TXEVT is an interrupt
from EMAC.
Figure 18. Transmit Pacer and Interrupt Combiner
Transmit pacer and interrupt combiner
TXEVT[0]
TXEVT[1]
TXEVT[2]
TXEVT[3]
TXEVT[4]
TXEVT[5]
TXEVT[6]
TXEVT[7]
Pacing block
Pacing block
Pacing block
Pacing block
Pacing block
Pacing block
Pacing block
Pacing block
EW_INTCTL[8]
EW_INTCTL[9]
EW_INTCTL[10]
EW_INTCTL[11]
EW_INTCTL[12]
EW_INTCTL[13]
EW_INTCTL[14]
EW_INTCTL[15]
MACTXINT
PS_TICK
EW_INTCTL[15:8]
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2.7.5
Receive Pacer and Interrupt Combiner (RPIC)
The receive pacer and interrupt combiner (RPIC) block performs following functions:
•
•
Implements pacing for receive events.
Combines the output of the pacer module based on the settings of bits 16 to 23 in the EW_INTCTL
register and generates a single MACRXINT interrupt per the C64x+ megamodule.
•
•
Receives a single PS_TICK and forwards it to all the pacing blocks.
Allows, per interrupt enabling or disabling of the interrupts, the setting of bits 16 to 23 in the
EW_INTCTL register.
Figure 19 shows the block diagram of receive pacer and interrupt combiner (RPIC).
Figure 19. Receive Pacer and Interrupt Combiner
Receive pacer and interrupt combiner
RXEVT[0]
RXEVT[1]
RXEVT[2]
RXEVT[3]
RXEVT[4]
RXEVT[5]
RXEVT[6]
RXEVT[7]
Pacing block
Pacing block
Pacing block
Pacing block
Pacing block
Pacing block
Pacing block
Pacing block
EW_INTCTL[16]
EW_INTCTL[17]
EW_INTCTL[18]
EW_INTCTL[19]
EW_INTCTL[20]
EW_INTCTL[21]
EW_INTCTL[22]
EW_INTCTL[23]
MACRXINT
PS_TICK
EW_INTCTL[23:16]
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2.7.6
Common Interrupt Combiner (CIC)
The common interrupt combiner (CIC) block performs following functions:
•
•
•
Combines the two common interrupts from EMAC (HOST and STAT) with the two MDIO interrupts
(MDIO_LINT and MDIO_USER) and generates a single MACINT interrupt per theC64x+ megamodule.
Performs a level-to-pulse conversion of the interrupts because the interrupts from EMAC and MDIO
are level sensitive and the C64x+ megamodule expects a pulse interrupt.
Allows, per interrupt enabling or disabling of the interrupts, the setting of bits 1 to 4 in the EW_INTCTL
register.
Figure 20 is the block diagram representing common interrupt combiner.
Figure 20. Common Interrupt Combiner
Common interrupt combiner block
HOST
EW_INTCTL[1]
STAT
MACINT
EW_INTCTL[2]
MDIO_LINT
EW_INTCTL[3]
MDIO_USER
EW_INTCTL[4]
EW_INTCTL[4:1]
2.8 Management Data Input/Output (MDIO) Module
The Management Data Input/Output (MDIO) module manages up to 32 physical layer (PHY) devices
connected to the Ethernet Media Access Controller (EMAC). The MDIO module allows almost transparent
operation of the MDIO interface with little maintenance from the CPU.
The MDIO module enumerates all PHY devices in the system by continuously polling 32 MDIO addresses.
Once it detects a PHY device, the MDIO module reads the PHY status register to monitor the PHY link
state. The MDIO module stores link change events that can interrupt the CPU. The event storage allows
the CPU to poll the link status of the PHY device without continuously performing MDIO module accesses.
However, when the system must access the MDIO module for configuration and negotiation, the MDIO
module performs the MDIO read or write operation independent of the CPU. This independent operation
allows the DSP to poll for completion or interrupt the CPU once the operation has completed.
2.8.1
MDIO Module Components
and MDIO), and to the DSP core through the EMIC module and the configuration bus. The MDIO module
consists of the following logical components:
•
•
•
•
MDIO clock generator
Global PHY detection and link state monitoring
Active PHY monitoring
PHY register user access
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Figure 21. MDIO Module Block Diagram
Peripheral
clock
MDIO
clock
generator
MDCLK
MDIO
MDIO
interface
USERINT
EMIC
module
LINKINT
PHY
monitoring
PHY
polling
Control
registers
and logic
Configuration bus
2.8.1.1
2.8.1.2
MDIO Clock Generator
The MDIO clock generator controls the MDIO clock based on a divide-down of the peripheral clock
(CPUCLK/6). The MDIO clock is specified to run up to 2.5 MHz, although typical operation would be 1.0
MHz. As the peripheral clock frequency is variable (CPUclk/6), the application software or driver controls
the divide-down amount.
Global PHY Detection and Link State Monitoring
The MDIO module enumerates all PHY devices in the system by continuously polling all 32 MDIO
addresses. The module tracks whether a PHY on a particular address has responded, and whether the
PHY currently has a link. This information allows the software application to quickly determine which
MDIO address the PHY is using, and if the system is using more than one PHY. The software application
can then quickly switch between PHYs based on their current link status.
2.8.1.3
Active PHY Monitoring
Once a PHY candidate has been selected for use, the MDIO module transparently monitors its link state
by reading the PHY status register. The MDIO device stores link change events that may optionally
interrupt the CPU. Thus, the system can poll the link status of the PHY device without continuously
performing MDIO accesses. Up to two PHY devices can be actively monitored at any given time.
2.8.1.4
PHY Register User Access
When the DSP must access the MDIO for configuration and negotiation, the PHY access module performs
the actual MDIO read or write operation independent of the CPU. Thus, the CPU can poll for completion
or receive an interrupt when the read or write operation has been performed. There are two user access
registers (USERACCESS0 and USERACCESS1), allowing the software to submit up to two access
requests simultaneously. The requests are processed sequentially.
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2.8.2
MDIO Module Operational Overview
The MDIO module implements the 802.3 serial management interface to simultaneously interrogate and
control up to two Ethernet PHYs, using a shared two-wired bus. It separately performs auto-detection and
records the current link status of up to 32 PHYs, polling all 32 MDIO addresses.
Application software uses the MDIO module to configure the auto-negotiation parameters of the primary
PHY attached to the EMAC, retrieve the negotiation results, and configure required parameters in the
EMAC. Up to two Ethernet PHYs can be directly controlled and queried. The Media Independent Interface
addresses of these two PHY devices are specified in the PHYADRMON fields of the USERPHYSELn
register. The module can be programmed to trigger a CPU interrupt on a PHY link change event by setting
the LINKINTENB bit in USERPHYSELn. Reads and writes to registers in these PHY devices are
performed using the USERACCESSn register.
The MDIO module powers up in an idle state until it is enabled by setting the ENABLE bit in the
CONTROL register. This also configures the MDIO clock divider and preamble mode selection. The MDIO
preamble is enabled by default, but it can be disabled if none of the connected PHYs require it.
Once the MDIO module is enabled, the MDIO interface state machine continuously polls the PHY link
status (by reading the generic PHY Status register) of all possible 32 PHY addresses and records the
results in the ALIVE and LINK registers. The corresponding bit for each PHY (0-31) is set in the ALIVE
register if the PHY responded to the read request. The corresponding bit is set in the LINK register if the
PHY responded and also is currently linked. In addition, any PHY register read transactions initiated by
the application software using the USERACCESSn register cause the ALIVE register to be updated.
The USERPHYSELn register is used to track the link status of any two of the 32 possible PHY addresses.
Changes in the link status of the two monitored PHYs sets the appropriate bit in the LINKINTRAW and
LINKINTMASKED registers, if they are enabled by the LINKINTENB bit in USERPHYSELn.
While the MDIO module is enabled, the host can issue a read or write transaction over the management
interface using the DATA, PHYADR, REGADR, and WRITE bits in the USERACCESSn register. When
the application sets the GO bit in USERACCESSn, the MDIO module begins the transaction without any
further intervention from the CPU. Upon completion, the MDIO module clears the GO bit and sets the
USERINTRAW[0-1] bit in the USERINTRAW register corresponding to the USERACCESSn used. The
corresponding USERINTMASKED bit in the USERINTMASKED register may also be set, depending on
the mask setting configured in the USERINTMASKSET and USERINTMASKCLEAR registers.
A round-robin arbitration scheme schedules transactions that may be queued using both USERACCESS0
and USERACCESS1. The application software must verify the status of the GO bit in USERACCESSn
before initiating a new transaction to ensure that the previous transaction has completed. The application
software can use the ACK bit in USERACCESSn to determine the status of a read transaction.
2.8.2.1
Initializing the MDIO Module
To have the application software or device driver initialize the MDIO device, perform the following:
1. Configure the PREAMBLE and CLKDIV bits in the CONTROL register.
2. Enable the MDIO module by setting the ENABLE bit in the CONTROL register.
3. The ALIVE register can be read after a delay to determine which PHYs responded, and the LINK
register can determine which of those (if any) already have a link.
4. Set up the appropriate PHY addresses in the USERPHYSELn register, and set the LINKINTENB bit to
enable a link change event interrupt if desirable.
5. If an interrupt on a general MDIO register access is desired, set the corresponding bit in the
USERINTMASKSET register to use the USERACCESSn register. If only one PHY is to be used, the
application software can set up one of the USERACCESSn registers to trigger a completion interrupt.
The other register is not set up.
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2.8.2.2
Writing Data to a PHY Register
The MDIO module includes a user access register (USERACCESSn) to directly access a specified PHY
device. To write a PHY register, perform the following:
1. Ensure that the GO bit in the USERACCESSn register is cleared.
2. Write to the GO, WRITE, REGADR, PHYADR, and DATA bits in USERACCESSn corresponding to the
desired PHY and PHY register.
3. The write operation to the PHY is scheduled and completed by the MDIO module. Completion of the
write operation can be determined by polling the GO bit in USERACCESSn for a 0.
4. Completion of the operation sets the corresponding bit in the USERINTRAW register for the
USERACCESSn used. If interrupts have been enabled on this bit using the USERINTMASKSET
register, then the bit is also set in the USERINTMASKED register and an interrupt is triggered on the
DSP.
2.8.2.3
Reading Data From a PHY Register
The MDIO module includes a user access register (USERACCESSn) to directly access a specified PHY
device. To read a PHY register, perform the following:
1. Ensure that the GO bit in the USERACCESSn register is cleared.
2. Write to the GO, REGADR, and PHYADR bits in USERACCESSn corresponding to the desired PHY
and PHY register.
3. The read data value is available in the DATA bits of USERACCESSn after the module completes the
read operation on the serial bus. Completion of the read operation can be determined by polling the
GO and ACK bits in USERACCESSn. Once the GO bit has cleared, the ACK bit is set on a successful
read.
4. Completion of the operation sets the corresponding bit in the USERINTRAW register for the
USERACCESSn used. If interrupts have been enabled on this bit using the USERINTMASKSET
register, then the bit is also set in the USERINTMASKED register and an interrupt is triggered on the
DSP.
2.8.2.4
Example of MDIO Register Access Code
The MDIO module uses the USERACCESSn register to access the PHY control registers. Software
functions that implement the access process include the following four macros:
PHYREG_read (regadr, phyadr )
PHYREG_write(regadr, phyadr, data )
PHYREG_wait ( )
Starts the process of reading a PHY register
Starts the process of writing a PHY register
Synchronizes operation (makes sure read/write is idle)
Waits for read to complete and returns data read
PHYREG_wait Results (results )
It is not necessary to wait after a write operation, as long as the status is checked before every operation
to make sure the MDIO hardware is idle. An alternative approach is to call PHYREG_wait () after every
write, and PHYREG_wait Results () after every read, then the hardware can be assumed to be idle when
starting a new operation.
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The implementation of these macros using the register layer Chip Support Library (CSL) is shown in
Example 3 (USERACCESS0 is assumed).
Note that this implementation does not check the ACK bit on PHY register reads; in other words, it does
not follow the procedure outlined in Section 2.8.2.3. As the ALIVE register initially selects a PHY, it is
assumed that the PHY is acknowledging read operations. It is possible that a PHY could become inactive
at a future point in time. For example, a PHY can have its MDIO addresses changed while the system is
running, although it is not a common occurrence. This condition can be tested by periodically checking the
PHY state in the ALIVE register.
Example 3. MDIO Register Access Macros
#define PHYREG_read(regadr, phyadr)
\
MDIO_REGS->USERACCESS0 =
\
\
CSL_FMK(MDIO_USERACCESS0_GO,1u)
CSL_FMK(MDIO_USERACCESS0_REGADR,regadr) |
CSL_FMK(MDIO_USERACCESS0_PHYADR,phyadr)
|
\
\
#define PHYREG_write(regadr, phyadr, data)
MDIO_REGS->USERACCESS0 =
CSL_FMK(MDIO_USERACCESS0_GO,1u)
CSL_FMK(MDIO_USERACCESS0_WRITE,1)
\
|
|
\
\
\
\
CSL_FMK(MDIO_USERACCESS0_REGADR,regadr) |
CSL_FMK(MDIO_USERACCESS0_PHYADR,phyadr) |
CSL_FMK(MDIO_USERACCESS0_DATA, data)
#define PHYREG_wait()
while (CSL_FEXT(MDIO_REGS->USERACCESS0,MDIO_USERACCESS0_GO) )
\
#define PHYREG_wait Results(results
)
{
\
while (CSL_FEXT(MDIO_REGS->USERACCESS0,MDIO_USERACCESS0_GO) );
\
results = CSL_FEXT(MDIO_REGS->USERACCESS0, MDIO_USERACCESS0_DATA); }
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2.9 EMAC Module
This section discusses the architecture and basic functions of the EMAC sub-module integrated with the
TCI6486/C6472 device.
2.9.1
EMAC Module Components
There are two EMAC modules integrated with the TCI6486/C6472 device. EMAC0 interfaces with PHY
through one of five interfaces: MII, GMII, S3MII, RMII, or RGMII. EMAC1 interfaces with PHY through one
of three interfaces: S3MII, RMII, or RGMII. In Figure 22, the number associated with each MII interface
shows the EMAC module with which the interface is available. For example: RMII0 is EMAC0 interface,
RMII1 is EMAC1 interface.
Figure 22. EMAC Module Block Diagram
Clock and
reset logic
Receive
address
Configuration bus
Receive
DMA engine
Receive
FIFO
MAC
receiver
MII0/GMII0
CPPI
buffer
manager
RMII0, RMII1
RGMII0, RGMII1
S3MII0, S3MII1
Transmit
DMA engine
Transmit
FIFO
MAC
transmitter
SYNC
Interrupt
controller
State
RAM
EMIC
Statistics
Control
registers
Configuration bus
Each EMAC peripheral used has the following components:
The receive path:
•
–
–
–
–
Receive DMA engine
The receive DMA engine performs the data transfer between the receive FIFO and the device
internal or external memory. It interfaces to the processor through the bus arbiter in the CPPI buffer
manager. This DMA engine is totally independent of the TCI6486/C6472 DSP EDMA.
Receive FIFO
The receive FIFO consists of 68 cells of 64 bytes each and the associated control logic. The FIFO
buffers receive data in preparation for writing into packet buffers in device memory and also enable
receive FIFO flow control.
MAC receiver
The MAC receiver detects and processes incoming network frames, de-frames them, and places
them into the receive FIFO. The MAC receiver also detects errors and passes statistics to the
statistics RAM.
Receive address sub-module
The receive address sub-module performs address matching and address filtering based on the
incoming packet's destination address. It contains a 32 x 53 bit two-port RAM in which up to 32
addresses can be stored to be either matched or filtered by the EMAC.
The RAM may contain multicast packet addresses, but the associated channel must have the
unicast enable bit set, even though it is a multicast address. The unicast enable bits are used with
multicast addresses in the receive address RAM (not the multicast hash enable bits). Therefore,
hash matches can be disabled, but specific multicast addresses can be matched (or filtered) in the
RAM. If a multicast packet hash matches, the packet may still be filtered in the RAM. Each packet
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can be sent to only a single channel.
The transmit path:
•
–
–
–
Transmit DMA engine
The transmit DMA engine performs the data transfer between the device internal or external
memory and the transmit FIFO. It interfaces to the processor through the bus arbiter in the CPPI
buffer manager. This DMA engine is totally independent of the TCI6486/C6472 DSP EDMA.
Transmit FIFO
The transmit FIFO consists of 24 cells of 64 bytes each and the associated control logic. This
enables a packet of 1518 bytes (standard Ethernet packet size) to be sent without the possibility of
under-run. The FIFO buffers data in preparation for transmission.
MAC transmitter
The MAC transmitter formats frame data from the transmit FIFO and transmits the data using the
CSMA/CD access protocol. The frame CRC can be automatically appended, if required. The MAC
transmitter also detects transmission errors and passes statistics to the statistics registers.
•
•
•
•
•
Statistics logic
The statistics logic RAM counts and stores the Ethernet statistics, keeping track of 36 different
Ethernet packet statistics.
State RAM
The state RAM contains the head descriptor pointers and completion pointers registers for both
transmit and receive channels.
Interrupt controller
The interrupt controller contains the interrupt-related registers and logic. The 18 raw EMAC interrupts
are input to this sub-module and masked module interrupts are output.
Control registers and logic
The EMAC is controlled by a set of memory-mapped registers. The control logic also signals transmit,
receive, and status related interrupts to the CPU through the EMIC module.
Clock and reset logic
The clock and reset sub-module generates all the clocks and resets for the EMAC peripheral.
2.9.2
EMAC Module Operational Overview
After reset, initialization, and configuration of the EMAC, the application software running on the host may
initiate transmit operations. Transmit operations are initiated by host writes to the appropriate transmit
channel head descriptor pointer contained in the state RAM block. The transmit DMA controller then
fetches the first packet in the packet chain from memory. The DMA controller writes the packet into the
transmit FIFO in bursts of 64-byte cells. The MAC transmitter initiates the packet transmission when either
the threshold number of cells (configurable via TXCELLTHRESH in the FIFOCONTROL register) have
been written to the transmit FIFO, or a complete packet has been written, whichever is smaller. The SYNC
block transmits the packet over one of the MII interfaces in accordance with the 802.3 protocol. The
statistics block counts transmit statistics.
Receive operations are initiated by host writes to the appropriate receive channel head descriptor pointer
after host initialization and configuration. The SYNC sub-module receives packets and strips off the
Ethernet related protocol. The packet data is input to the MAC receiver, which checks for address match
(in conjunction with the receive address block) and processes errors. Accepted packets are written to the
receive FIFO in bursts of 64-byte cells. The receive DMA controller then writes the packet data to memory.
The statistics block counts receive statistics.
The EMAC module operates independently of the CPU. It is configured and controlled by its register set
mapped into device memory. Information about data packets is communicated using 16-byte descriptors.
For transmit operations, each 16-byte descriptor describes a packet or packet fragment in the system's
internal or external memory. For receive operations, each 16-byte descriptor represents a free packet
buffer or buffer fragment. On both transmit and receive, an Ethernet packet is allowed to span one or
more memory fragments, represented by one 16-byte descriptor per fragment. In typical operation, there is
only one descriptor per receive buffer, but transmit packets may be fragmented, depending on the
software architecture.
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An interrupt is issued to the CPU whenever a transmit or receive operation has completed. However, it is
not necessary for the CPU to service the interrupt while there are additional resources available. In other
words, the EMAC continues to receive Ethernet packets until its receive descriptor list has been
exhausted. On transmit operations, the transmit descriptors need only be serviced to recover their
associated memory buffer. Thus, it is possible to delay servicing of the EMAC interrupt if there are
real-time tasks to perform.
Eight channels are supplied for both transmit and receive operations. On transmit, the eight channels
represent eight independent transmit queues. The EMAC can be configured to treat these channels as an
equal priority round-robin queue, or as a set of eight fixed-priority queues. On receive, the eight channels
represent eight independent receive queues with packet classification. Packets are classified based on the
destination MAC address. Each of the eight channels is assigned its own MAC address, enabling the
EMAC module to act like eight virtual MAC adapters. Also, specific types of frames can be sent to specific
channels. For example, multicast, broadcast, or other (promiscuous, error, etc.) frames can each be
received on a specific receive channel queue.
The EMAC tracks 36 different statistics, as well as recording the status of each individual packet in its
corresponding packet descriptor.
2.10 Media Independent Interfaces
The EMAC0 supports MII, GMII, RMII, S3MII and RGMII physical interfaces to external PHY devices,
whereas the EMAC1 supports RMII, S3MII and RGMII interfaces.
The following sections discuss the operation of these interfaces in 10/100 Mbps mode (MII, RMII, GMII
and RGMII), and 1000 Mbps mode (GMII and RGMII). An IEEE 802.3 compliant Ethernet MAC controls
these interfaces.
2.10.1 Data Reception
2.10.1.1 Receive Control
Data received from the PHY is interpreted and output to the EMAC receive FIFO. Interpretation involves
detection and removal of the preamble and start-of-frame delimiter, extraction of the address and frame
length, data handling, error checking and reporting, cyclic redundancy checking (CRC), and statistics
control signal generation. Receive address detection and frame filtering of the frames that do not
address-match is performed outside the Media Independent interface.
2.10.1.2 Receive Inter-Frame Interval
The 802.3 required inter-packet gap (IPG) is 24 receive data clocks (96 bit times). However, the EMAC
can tolerate a reduced IPG (2 receive clocks in 10/100 Mbps mode and 5 receive clocks in 1000 Mbps
mode) with a correct preamble and start frame delimiter. This interval between frames must comprise (in
the following order):
1. An Inter-Packet Gap (IPG).
2. A seven bytes preamble (all bytes 55h).
3. A one byte start-of-frame delimiter (5Dh).
2.10.1.3 Receive Flow Control
When enabled and triggered, receive flow control is initiated to limit the EMAC from further frame
reception. Two forms of receive flow control are implemented on the TCI6486/C6472 device:
•
•
Receive buffer flow control
Receive FIFO flow control
When enabled and triggered, receive buffer flow control prevents further frame reception based on the
number of free buffers available. Receive buffer flow control issues flow control collisions in half-duplex
mode and IEEE 802.3X pause frames for full-duplex mode.
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Receive buffer flow control is triggered when the number of free buffers in any enabled receive channel
(RXnFREEBUFFER) is less than or equal to the channel flow control threshold register
(RXnFLOWTHRESH) value. Receive flow control is independent of receive QOS, except that both use the
free buffer values.
When enabled and triggered, receive FIFO flow control prevents further frame reception based on the
number of cells currently in the receive FIFO. Receive FIFO flow control may be enabled only in
full-duplex mode (FULLDUPLEX bit is set in the MACCONTROL register). Receive flow control prevents
reception of frames on the port until all of the triggering conditions clear, at which time frames may again
be received by the port.
Receive FIFO flow control is triggered when the occupancy of the FIFO is greater than or equal to the
RXFIFOFLOWTHRESH value in the FIFOCONTROL register. The RXFIFOFLOWTHRESH value must be
greater than or equal to 1h and less than or equal to 42h (decimal 66). The RXFIFOFLOWTHRESH reset
value is 2h.
Receive flow control is enabled by the RXBUFFERFLOWEN bit and the RXFIFOFLOWEN bit in the
MACCONTROL register. The FULLDUPLEX bit in the MACCONTROL register configures the EMAC for
collision or IEEE 802.3X flow control.
2.10.1.4 Collision-Based Receive Buffer Flow Control
Collision-based receive buffer flow control provides a means of preventing frame reception when the
EMAC is operating in half-duplex mode (FULLDUPLEX bit is cleared in MACCONTROL register). When
receive flow control is enabled and triggered, the EMAC generates collisions for received frames. The jam
sequence transmitted is the 12-byte sequence C3.C3.C3.C3.C3.C3.C3.C3.C3.C3.C3.C3 in hexadecimal.
The jam sequence begins approximately when the source address starts to be received. These forced
collisions are not limited to a maximum of 16 consecutive collisions and are independent of the normal
back-off algorithm.
Receive flow control does not depend on the value of the incoming frame destination address. A collision
is generated for any incoming packet, regardless of the destination address, if any EMAC enabled
channel's free buffer register value is less than or equal to the channel's flow threshold value.
2.10.1.5 IEEE 802.3X Based Receive Buffer Flow Control
IEEE 802.3x based receive buffer flow control provides a means of preventing frame reception when the
EMAC is operating in full-duplex mode (the FULLDUPLEX bit is set in the MACCONTROL register). When
receive flow control is enabled and triggered, the EMAC transmits a pause frame to request that the
sending station stop transmitting for the period indicated within the transmitted pause frame.
The EMAC transmits a pause frame to the reserved multicast address at the first available opportunity
(immediately if currently idle, or following the completion of the frame currently being transmitted). The
pause frame contains the maximum possible value for the pause time (FFFFh). The EMAC counts the
receive pause frame time (decrements FF00h to 0) and retransmits an outgoing pause frame, if the count
reaches zero. When the flow control request is removed, the EMAC transmits a pause frame with a zero
pause time to cancel the pause request.
Note that transmitted pause frames are only a request to the other end station to stop transmitting.
Frames that are received during the pause interval are received normally (provided the receive FIFO is not
full).
Pause frames are transmitted if enabled and triggered, regardless of whether or not the EMAC is
observing the pause time period from an incoming pause frame.
The EMAC transmits pause frames as described below:
•
•
•
•
•
The 48-bit reserved multicast destination address 01.80.C2.00.00.01h.
The 48-bit source address (set via the MACSRCADDRLO and MACSRCADDRHI registers).
The 16-bit length/type field containing the value 88.08h.
The 16-bit pause opcode equal to 00.01h.
The 16-bit pause time value of FF.FFh. A pause-quantum is 512 bit-times. Pause frames sent to
cancel a pause request have a pause time value of 00.00h.
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•
•
Zero padding to 64-byte data length (EMAC transmits only 64-byte pause frames).
The 32-bit frame-check sequence (CRC word).
All quantities are hexadecimal and are transmitted most-significant-byte first. The least-significant-bit
(LSB) is transferred first in each byte.
If the RXBUFFERFLOWEN bit in the MACCONTROL register is cleared while the pause time is nonzero,
then the pause time is cleared and a zero count pause frame is sent.
2.10.2 Data Transmission
The EMAC passes data to the PHY from the transmit FIFO (when enabled). Data is synchronized to the
transmit clock rate. Transmission begins when there are TXCELLTHRESH cells of 64 bytes each, or a
complete packet, in the FIFO.
2.10.2.1 Transmit Control
A jam sequence is output if a collision is detected on a transmit packet. If the collision was late (after the
first 64 bytes have been transmitted), the collision is ignored. If the collision is not late, the controller will
back off before retrying the frame transmission. When operating in full-duplex mode, the carrier sense
(MCRS) and collision-sensing (MCOL) modes are disabled.
2.10.2.2 CRC Insertion
If the SOP buffer descriptor PASSCRC flag is cleared, the EMAC generates and appends a 32-bit
Ethernet CRC onto the transmitted data. For the EMAC-generated CRC case, a CRC (or placeholder) at
the end of the data is allowed but not required. The buffer byte count value should not include the CRC
bytes, if they are present.
If the SOP buffer descriptor PASSCRC flag is set, then the last four bytes of the transmit data are
transmitted as the frame CRC. The four CRC data bytes should be the last four bytes of the frame and
should be included in the buffer byte count value. The MAC performs no error checking on the outgoing
CRC.
2.10.2.3 Adaptive Performance Optimization (APO)
The EMAC incorporates adaptive performance optimization (APO) logic that may be enabled by setting
the TXPACE bit in the MACCONTROL register. Transmission pacing to enhance performance is enabled
when the TXPACE bit is set. Adaptive performance pacing introduces delays into the normal transmission
of frames, delaying transmission attempts between stations, and reducing the probability of collisions
occurring during heavy traffic (as indicated by frame deferrals and collisions). These actions increase the
chance of a successful transmission.
When a frame is deferred, suffers a single collision, multiple collisions, or excessive collisions, the pacing
counter is loaded with an initial value of 31. When a frame is transmitted successfully (without
experiencing a deferral, single collision, multiple collision, or excessive collision), the pacing counter is
decremented by 1 down to 0.
If the pacing counter is zero, this allows a new frame to immediately attempt transmission (after one IPG).
If the pacing counter is nonzero, the frame is delayed by a pacing delay of approximately four inter-packet
gap delays. APO only affects the IPG preceding the first attempt at transmitting a frame; APO does not
affect the back-off algorithm for re-transmitted frames.
2.10.2.4 Interpacket-Gap (IPG) Enforcement
The measurement reference for the IPG of 96 bit times is changed depending on frame traffic conditions.
If a frame is successfully transmitted without collision and MCRS is de-asserted within approximately 48
bit times of MTXEN being de-asserted, then 96 bit times is measured from MTXEN. If the frame suffered a
collision or MCRS is not de-asserted until more than approximately 48 bit times after MTXEN is
de-asserted, then 96 bit times (approximately, but not less) is measured from MCRS.
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2.10.2.5 Back Off
The EMAC implements the 802.3 binary exponential back-off algorithm.
2.10.2.6 Transmit Flow Control
When enabled, incoming pause frames are acted upon to prevent the EMAC from transmitting any further
frames. Incoming pause frames are only acted upon when the FULLDUPLEX and TXFLOWEN bits in the
MACCONTROL register are set. Pause frames are not acted upon in half-duplex mode. Pause frame
action is taken if enabled, but normally the frame is filtered and not transferred to memory. MAC control
frames are transferred to memory, if the RXCMFEN bit in the RXMBPENABLE register is set. The
TXFLOWEN and FULLDUPLEX bits affect whether MAC control frames are acted upon, but they have no
effect upon whether MAC control frames are transferred to memory or filtered.
Pause frames are a subset of MAC control frames with an opcode field of 0001h. Incoming pause frames
are only acted upon by the EMAC if the following conditions occur:
•
•
•
The TXFLOWEN bit is set in the MACCONTROL register.
The frame's length is between 64 bytes and RXM AXLEN bytes inclusive.
The frame contains no CRC error or align/code errors.
The pause time value from valid frames is extracted from the two bytes following the opcode. The pause
time is loaded into the EMAC transmit pause timer and the transmit pause time period begins.
If a valid pause frame is received during the transmit pause time period of a previous transmit pause
frame, then either the destination address is not equal to the reserved multicast address or any enabled or
disabled unicast address, and the transmit pause timer immediately expires; or the new pause time value
is 0, and the transmit pause timer immediately expires. Otherwise, the EMAC transmit pause timer is set
immediately to the new pause frame pause time value. (Any remaining pause time from the previous
pause frame is discarded.)
If the TXFLOWEN bit in MACCONTROL is cleared, then the pause timer immediately expires.
The EMAC does not start the transmission of a new data frame any sooner than 512-bit times after a
pause frame with a non-zero pause time has finished being received (MRXDV going inactive). No
transmission begins until the pause timer has expired (the EMAC may transmit pause frames to initiate
outgoing flow control). Any frame already in transmission when a pause frame is received is completed
and unaffected.
Incoming pause frames consist of:
•
A 48-bit destination address equal to one of the following:
–
–
The reserved multicast destination address 01.80.C2.00.00.01h
Any EMAC 48-bit unicast address. Pause frames are accepted, regardless of whether the channel
is enabled.
•
•
•
•
•
•
The 48-bit source address of the transmitting device
The 16-bit length/type field containing the value 88.08h
The 16-bit pause opcode equal to 00.01h
The 16-bit pause time. A pause-quantum is 512 bit-times
Padding to 64-byte data length
The 32-bit frame-check sequence (CRC word)
All quantities are hexadecimal and are transmitted most-significant-byte first. The least-significant-bit
(LSB) is transferred first in each byte.
The padding is required to make up the frame to a minimum of 64 bytes. The standard allows pause
frames longer than 64 bytes to be discarded or interpreted as valid pause frames. The EMAC recognizes
any pause frame between 64 bytes and RXMAXLEN bytes in length.
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2.10.2.7 Speed, Duplex, and Pause Frame Support
The MAC can operate in half-duplex or full-duplex mode at 10 Mbps or 100 Mbps, and can operate in full
duplex only in 1000 Mbps. Pause frame support is included in 10/100/1000 Mbps modes as configured by
the host.
2.11 Packet Receive Operation
2.11.1 Receive DMA Host Configuration
To configure the receive DMA for operation, the host must perform the following actions:
•
•
•
•
Initialize the receive addresses
Initialize the RXnHDP registers to zero
Write the MACHASH1 and MACHASH2 registers, if hash matching multicast addressing is desired
Initialize the RXnFREEBUFFER, RXnFLOWTHRESH, and RXFILTERLOWTHRESH registers, if flow
control is to be enabled
•
•
•
•
•
•
Enable the desired receive interrupts using the RXINTMASKSET and RXINTMASKCLEAR registers
Set the appropriate configuration bits in the MACCONTROL register
Write the RXBUFFEROFFSET register value (typically zero)
Set up the receive channel(s) buffer descriptors and initialize the RXnHDP registers
Enable the receive DMA controller by setting the RXEN bit in the RXCONTROL register
Configure and enable the receive operation, as desired, in the RXMBPENABLE register and by using
the RXUNICASTSET and RXUNICASTCLEAR registers
2.11.2 Receive Channel Enabling
Each of the eight receive channels has an enable bit (RXCHnEN) in the RXUNICASTSET register that is
controlled using the RXUNICASTSET and RXUNICASTCLEAR registers. The RXCHnEN bits determine
whether the given channel is enabled (when set to 1) to receive frames with a matching unicast or
multicast destination address.
The RXBROADEN bit in the RXMBPENABLE register determines if broadcast frames are enabled or
filtered. If broadcast frames are enabled, then they are copied to only a single channel selected by the
RXBROADCH field of RXMBPENABLE register.
The RXMULTEN bit in the RXMBPENABLE register determines if hash matching multicast frames are
enabled or filtered. Incoming multicast addresses (group addresses) are hashed into an index in the hash
table. If the indexed bit is set, the frame hash will match and it will be transferred to the channel selected
by the RXMULTCH field when multicast frames are enabled. The multicast hash bits are set in the
MACHASH1 and MACHASH2 registers.
The RXPROMCH bits in the RXMBPENABLE register select the promiscuous channel to receive frames
selected by the RXCMFEN, RXCSFEN, RXCEFEN, and RXCAFEN bits. These four bits allow reception of
MAC control frames, short frames, error frames, and all frames (promiscuous), respectively.
The address RAM can be configured to set multiple unicast and/or multicast addresses to a given channel
(if the match bit is set in the RAM). Multicast addresses in the RAM are enabled by the RXUNICASTSET
register and not by the RXMULTEN bit in the RXMBPENABLE register. The RXMULTEN bit enables the
hash multicast match only. The address RAM takes precedence over the hash match.
If a multicast packet is received that hash matches (multicast packets enabled), but is filtered in the RAM,
then the packet is filtered. If a multicast packet does not hash match, regardless of whether or not hash
matching is enabled, but matches an enabled multicast address in the RAM, then the packet will be
transferred to the associated channel.
2.11.3 Receive Channel Addressing
The receive address block can store up to 32 addresses to be filtered or matched. Before enabling packet
reception, all the address RAM locations should be initialized, including locations to be unused. The
system software is responsible for adding and removing addresses from the RAM.
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A MAC address location in RAM is 53 bits wide and consists of:
•
•
48 bits of the MAC address
3 bits for the channel to which a valid address match will be transferred. The channel is a don't care if
the MATCHFILT bit is cleared.
•
•
A valid bit
A match or filter bit
First, write the index into the address RAM in the MACINDEX register to start writing a MAC address.
Then write the upper 32 bits of the MAC address (MACADDRHI register), and then the lower 16 bits of
MAC address with the VALID and MATCHFILT control bits (MACADDRLO). The valid bit should be
cleared for the unused locations in the receive address RAM.
The most common uses for the receive address sub-module are:
•
Set EMAC in promiscuous mode, using the RXCAFEN and RXPROMCH bits in the RXMBPENABLE
register. Then filter up to 32 individual addresses, which can be both unicast and/or multicast.
•
Disable the promiscuous mode (RXCAFEN = 0) and match up to 32 individual addresses, multicast
and/or unicast.
2.11.4 Hardware Receive QOS Support
Hardware receive quality of service (QOS) is supported, when enabled, by the Tag Protocol Identifier
format and the associated Tag Control Information (TCI) format priority field. When the incoming frame
length/type value is equal to 81.00h, the EMAC recognizes the frame as an Ethernet Encoded Tag
Protocol Type. The two octets immediately following the protocol type contain the 16-bit TCI field. Bits
15-13 of the TCI field contain the received frames priority (0 to 7). The received frame is a low-priority
frame if the priority value is 0 to 3. The received frame is a high-priority frame if the priority value is 4 to 7.
All frames that have a length/type field value not equal to 81.00h are low-priority frames.
Received frames that contain priority information are determined by the EMAC as:
•
A 48-bit (6 bytes) destination address equal to:
–
–
–
The destination station's individual unicast address
The destination station's multicast address (MACHASH1 and MACHASH2 registers)
The broadcast address of all ones
•
•
•
•
•
A 48-byte (6 bytes) source address
The 16-bit (2 bytes) length/type field containing the value 81.00h
The 16-bit (2 bytes) TCI field with the priority field in the upper 3 bits
Data bytes
The 4-bytes CRC
The RXFILTERLOWTHRESH and the RXnFREEBUFFER registers are used in conjunction with the
priority information to implement receive hardware QOS. Low-priority frames are filtered if the number of
free buffers (RXnFREEBUFFER) for the frame channel is less than or equal to the filter low threshold
(RXFILTERLOWTHRESH) value. Hardware QOS is enabled by the RXQOSEN bit in the RXMBPENABLE
register.
2.11.5 Host Free Buffer Tracking
The host must track free buffers for each enabled channel (including unicast, multicast, broadcast, and
promiscuous) if receive QOS or receive flow control is used. Disabled channel free buffer values are don't
cares. During initialization, the host should write the number of free buffers for each enabled channel to
the appropriate RXnFREEBUFFER register. The EMAC decrements the appropriate channel's free buffer
value for each buffer used. When the host reclaims the frame buffers, the host should write the channel
free buffer register with the number of reclaimed buffers (write to increment). There are a maximum of 65
535 free buffers available. The RXnFREEBUFFER registers only need to be updated by the host if receive
QOS or flow control is used.
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2.11.6 Receive Channel Teardown
The host commands a receive channel teardown by writing the channel number to the RXTEARDOWN
register. When a teardown command is issued to an enabled receive channel, the following occurs:
•
•
•
•
•
•
Any current frame in reception completes normally.
The TDOWNCMPLT flag is set in the next buffer descriptor in the chain, if there is one.
The channel head descriptor pointer is cleared.
A receive interrupt for the channel is issued to the host.
The corresponding RXnCP register contains the value FFFF FFFCh.
The host should acknowledge a teardown interrupt with an FFFF FFFCh acknowledge value.
Channel teardown may be commanded on any channel at any time. The host is informed of the teardown
completion by the set teardown complete buffer descriptor bit. The EMAC does not clear any channel
enables due to a teardown command. A teardown command to an inactive channel issues an interrupt
that software should acknowledge with an FFFF FFFCh acknowledge value to RXnCP (note that there is
no buffer descriptor in this case). Software may read RXnCP to determine if the interrupt was due to a
commanded teardown. The read value is FFFF FFFCh if the interrupt was due to a teardown command.
2.11.7 Receive Frame Classification
Received frames are proper, or good, frames if they are between 64 and RXMAXLEN in length (inclusive)
and contain no code, align, or CRC errors.
Received frames are long frames if their frame count exceeds the value in the RXMAXLEN register. The
RXMAXLEN register default reset value is 5EEh (1518 in decimal). Long received frames are either
oversized or jabber frames. Long frames with no errors are oversized frames; long frames with CRC,
code, or alignment errors are jabber frames.
Received frames are short frames if their frame count is less than 64 bytes. Short frames that address
match and contain no errors are undersized frames; short frames with CRC, code, or alignment errors are
fragment frames. If the frame length is less than or equal to 20, then the frame CRC is passed, regardless
of whether the RXPASSCRC bit is set or cleared in the RXMBPENABLE register.
A received long packet always contains RXMAXLEN number of bytes transferred to memory (if the
RXCEFEN bit is set in RXMBPENABLE) regardless of the value of the RXPASSCRC bit. Following is an
example with RXMAXLEN set to 1518:
•
•
•
•
•
If the frame length is 1518, then the packet is not a long packet and there are 1514 or 1518 bytes
transferred to memory depending on the value of the RXPASSCRC bit.
If the frame length is 1519, there are 1518 bytes transferred to memory regardless of the
RXPASSCRC bit value. The last three bytes are the first three CRC bytes.
If the frame length is 1520, there are 1518 bytes transferred to memory regardless of the
RXPASSCRC bit value. The last two bytes are the first two CRC bytes.
If the frame length is 1521, there are 1518 bytes transferred to memory regardless of the
RXPASSCRC bit value. The last byte is the first CRC byte.
If the frame length is 1522, there are 1518 bytes transferred to memory. The last byte is the last data
byte.
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2.11.8 Promiscuous Receive Mode
When the promiscuous receive mode is enabled by setting the RXCAFEN bit in the RXMBPENABLE
register, non-address matching frames that would normally be filtered are transferred to the promiscuous
channel. Address matching frames that would normally be filtered due to errors are transferred to the
address match channel when the RXCAFEN and RXCEFEN bits are set. Address matching frames with
the filter bit set (MATCHFILT = 0) are always filtered regardless of the RXCAFEN and RXCEFEN bit
setting. A frame is considered to be an address matching frame only if it is enabled to be received on a
unicast, multicast, or broadcast channel. Frames received to disabled unicast, multicast, or broadcast
channels are considered non-address matching.
MAC control frames address match only if the RXCMFEN bit is set. RXCEFEN and RXCSFEN determine
whether error frames are transferred to memory or not, but they do not determine whether error frames
are address matching or not. Short frames are a special type of error frames.
A single channel is selected as the promiscuous channel by the RXPROMCH field in the RXMBPENABLE
register. The promiscuous receive mode is enabled by the RXCMFEN, RXCEFEN, RXCSFEN, and
frames are frames that are between 64 and RXMAXLEN bytes in length inclusive and contain no code,
align, or CRC errors.
Table 14. Receive Frame Treatment Summary
Address
Match
RXMBPENABLE Bits
RXCAFEN RXCEFEN RXCMFEN RXCSFEN Frame Treatment
0
0
0
0
1
1
X
0
0
X
0
0
X
0
1
No frames transferred.
Proper frames transferred to promiscuous channel.
Proper/undersized data frames transferred to promiscuous
channel.
0
0
0
1
1
1
0
0
1
1
1
0
0
1
0
Proper data and control frames transferred to promiscuous
channel.
Proper/undersized data and control frames transferred to
promiscuous channel.
Proper/oversize/jabber/code/align/CRC data frames transferred
to promiscuous channel. No control or undersized/fragment
frames are transferred.
0
0
0
1
1
1
1
1
1
0
1
1
1
0
1
Proper/undersized/fragment/oversize/jabber/code/align/CRC
data frames transferred to promiscuous channel. No control
frames are transferred.
Proper/oversize/jabber/code/align/CRC data and control frames
transferred to promiscuous channel. No undersized frames are
transferred.
All non-address matching frames with and without errors
transferred to promiscuous channel.
1
1
X
X
0
0
0
0
0
1
Proper data frames transferred to address match channel.
Proper/undersized data frames transferred to address match
channel.
1
1
1
X
X
X
0
0
1
1
1
0
0
1
0
Proper data and control frames transferred to address match
channel.
Proper/undersized data and control frames transferred to
address match channel.
Proper/oversize/jabber/code/align/CRC data frames transferred
to address match channel. No control or undersized frames are
transferred.
1
X
1
0
1
Proper/oversize/jabber/fragment/undersized/code/align/CRC
data frames transferred to address match channel. No control
frames are transferred.
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Table 14. Receive Frame Treatment Summary (continued)
Address
Match
RXMBPENABLE Bits
RXCAFEN RXCEFEN RXCMFEN RXCSFEN Frame Treatment
1
X
1
1
0
Proper/oversize/jabber/code/align/CRC data and control frames
transferred to address match channel. No undersized/fragment
frames are transferred.
1
X
1
1
1
All address matching frames with and without errors transferred
to the address match channel.
2.11.9 Receive Overrun
The types of receive overruns are:
•
•
•
•
FIFO start-of-frame overrun (FIFO_SOF)
FIFO middle-of-frame overrun (FIFO_MOF)
DMA start-of-frame overrun (DMA_SOF)
DMA middle-of-frame overrun (DMA_MOF)
The statistics counters used to track these types of receive overruns are:
•
•
•
Receive Start-of-Frame Overruns Register (RXSOFOVERRUNS)
Receive Middle-of-Frame Overruns Register (RXMOFOVERRUNS)
Receive DMA Overruns Register (RXDMAOVERRUNS)
Start-of-frame overruns happen when there are no resources available when frame reception begins.
Start-of-frame overruns increment the appropriate overrun statistic(s) and the frame is filtered.
Middle-of-frame overruns happen when there are some resources to start the frame reception, but the
resources run out during frame reception. In normal operation, a frame that overruns after starting the
frame reception is filtered and the appropriate statistic(s) are incremented; however, the RXCEFEN bit in
is handled for the middle-of-frame overrun.
Table 15. Middle-of-Frame Overrun Treatment
Address Match
RXCAFEN
RXCEFEN
Middle-of-Frame Overrun Treatment
Overrun frame filtered.
0
0
0
0
1
1
X
0
1
Overrun frame filtered.
As much frame data as possible is transferred to the promiscuous channel
until overrun. The appropriate overrun statistic(s) is incremented and the
OVERRUN and NOMATCH flags are set in the SOP buffer descriptor. Note
that the RXMAXLEN number of bytes cannot be reached for an overrun to
occur (it would be truncated and be a jabber or oversize).
1
1
X
X
0
1
Overrun frame filtered with the appropriate overrun statistic(s) incremented.
As much frame data as possible is transferred to the address match
channel until overrun. The appropriate overrun statistic(s) is incremented
and the OVERRUN flag is set in the SOP buffer descriptor. Note that the
RXMAXLEN number of bytes cannot be reached for an overrun to occur (it
would be truncated).
2.12 Packet Transmit Operation
The transmit DMA is an eight channel interface. Priority between the eight queues may be either fixed or
round robin as selected by the TXPTYPE bit in the MACCONTROL register. If the priority type is fixed,
then channel 7 has the highest priority and channel 0 has the lowest priority. Round robin priority
proceeds from channel 0 to channel 7.
2.12.1 Transmit DMA Host Configuration
To configure the transmit DMA for operation, the host must perform the following:
•
Write the MACSRCADDRLO and MACSRCADDRHI registers (used for pause frames on transmit).
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•
•
•
•
•
•
Initialize the TXnHDP registers to zero.
Enable the desired transmit interrupts using the TXINTMASKSET and TXINTMASKCLEAR registers.
Set the appropriate configuration bits in the MACCONTROL register.
Set up the transmit channel(s) buffer descriptors in host memory.
Enable the transmit DMA controller by setting the TXEN bit in the TXCONTROL register.
Write the appropriate TXnHDP registers with the pointer to the first descriptor to start transmit
operations.
2.12.2 Transmit Channel Teardown
The host commands a transmit channel teardown by writing the channel number to the TXTEARDOWN
register. When a teardown command is issued to an enabled transmit channel, the following occurs:
•
•
•
•
•
•
Any frame currently in transmission completes normally.
The TDOWNCMPLT flag is set in the next SOP buffer descriptor in the chain, if there is one.
The channel head descriptor pointer is cleared.
A transmit interrupt is issued, informing the host of the channel teardown.
The corresponding TXnCP register contains the value FFFF FFFCh.
The host should acknowledge a teardown interrupt with an FFFF FFFCh acknowledge value.
Channel teardown may be commanded on any channel at any time. The host is informed of the teardown
completion by the set teardown complete buffer descriptor bit (TDOWNCMPLT). The EMAC does not
clear any channel enables due to a teardown command. A teardown command to an inactive channel
issues an interrupt that software should acknowledge with an FFFF FFFCh acknowledge value to TXnCP
(note that there is no buffer descriptor). Software may read the interrupt acknowledge location (TXnCP) to
determine if the interrupt was due to a commanded teardown. The read value is FFFF FFFCh if the
interrupt was due to a teardown command.
2.13 Receive and Transmit Latency
The transmit FIFO contains twenty four 64-byte cells, and the receive FIFO contains sixty eight 64-byte
cells. The EMAC begins transmission of a packet on the wire after TXCELLTHRESH cells (configurable
through the FIFOCONTROL register) or a complete packet are available in the FIFO.
Transmit underrun cannot occur for packet sizes of TXCELLTHRESH times 64 bytes (or less). For larger
packet sizes, transmit underrun can occur if the memory latency is greater than the time required to
transmit a 64-byte cell on the wire; this is 0.512 ms in 1 Gbit mode, 5.12 ms in 100 Mbps mode, and 51.2
ms in 10 Mbps mode. The memory latency time includes all buffer descriptor reads for the entire cell data.
The EMAC transmit FIFO uses 24 cells; thus, underrun cannot happen for a normal size packet (less than
1536 packet bytes). Cell transmission can be configured to start only after an entire packet is contained in
the FIFO; for a maximum-size packet, set the TXCELLTHRESH field to the maximum possible value of
24.
Receive overrun is prevented if the receive memory cell latency is less than the time required to transmit a
64-byte cell on the wire (0.512 ms in 1 Gbps mode, 5.12 ms in 100 Mbps mode, or 51.2ms in 10 Mbps
mode). The latency time includes any required buffer descriptor reads for the cell data.
Latency to system's internal and external RAM can be controlled through the use of the transfer node
priority allocation register in the TCI6486/C6472 devices. Latency to descriptor RAM is low because RAM
is local to the EMAC, as it is part of the CPPI buffer manager.
2.14 Transfer Node Priority
The TCI6486/C6472 devices contain a system-level priority allocation register (PRI_ALLOC) that sets the
priority of the transfer node used in issuing memory transfer requests to system memory.
Although the EMAC has internal FIFOs to help alleviate memory transfer arbitration problems, the average
transfer rate of data read and written by the EMAC to internal or external DSP memory must be at least
equal to the Ethernet wire rate. In addition, the internal FIFO system cannot withstand a single memory
latency event greater than the time it takes to fill or empty a TXCELLTHRESH number of internal 64-byte
FIFO cells.
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For example, for 1000-Mbps operation, these restrictions translate into the following rules:
•
For the short-term average, each 64-byte memory read/write request from the EMAC must be serviced
in no more than 0.512 ms.
•
Any single latency event in request servicing can be no longer than (0.512 * TXCELLTHRESH) ms.
Bits [0-2] of the PRI_ALLOC register set the transfer node priority for EMAC0 in the device. Bits [12-14] of
the PRI_ALLOC register set the transfer node priority for EMAC1 in the device. A value of 000b has the
highest priority, while 111b has the lowest. The default priority assigned to EMAC0 and EMAC1 is 111b. It
is important to have a balance between all peripherals. In most cases, the default priorities will not need
adjustment.
2.15 Reset Considerations
2.15.1 Software Reset Considerations
For information on the chip level reset capabilities of various peripherals, see the TMS320TCI6486
Within the peripheral itself, the EMAC component of the Ethernet MAC peripheral can be placed in a reset
state by writing to the SOFTRESET register located in EMAC memory map. Writing a one to bit 0 of this
register causes the EMAC logic to be reset, and the register values to be set to their default values.
Software reset occurs when the receive and transmit DMA controllers are in an idle state to avoid locking
up the configuration bus; it is the responsibility of the software to verify that there are no pending frames to
be transferred. After writing a one to this bit, it may be polled to determine if the reset has occurred. A
value of one indicates that the reset has not yet occurred. A value of zero indicates that a reset has
occurred.
After a software reset operation, all the EMAC registers need to be re-initialized for proper data
transmission.
Unlike the EMAC module, the MDIO, EMIC modules, and CPPI buffer managers cannot be placed in reset
from a register inside their memory map.
2.15.2 Hardware Reset Considerations
When a hardware reset occurs, the EMAC peripheral will have its register values reset, and all the
sub-modules will return to their default state. After the hardware reset, the EMAC needs to be initialized
A hardware reset is the only means of recovering from the error interrupts (HOSTPEND), which are
triggered by errors in packet buffer descriptors. Before doing a hardware reset, you should inspect the
error codes in the MACSTATUS register. This register provides information about the software error type
2.15.3 RGMII Transmission
On device reset, packet transmissions on the RGMII interface are precluded for 4096 transmit clock cycles
after the RGMII link signal goes high. Transmission can be started only after 4096 cycles of transmit clock
after the link signal goes high. Any packet transmission attempt within 4096 clock cycles of transmit clock
will not cause an actual packet transmission over the RGMII interface. This restriction on packet
transmissions calls for a delay in the packet transmission after device reset. An approximate delay of 2 ms
after reset should be enough to start packet transmissions.
2.15.4 S3MII Transmission
On device reset, packet transmissions on the S3MII interface are precluded for 4096 transmit clock cycles
after the S3MII link signal goes high. Transmission can be started only after 4096 cycles of transmit clock
after the link signal goes high. Any packet transmission attempt within 4096 clock cycles of transmit clock
will not cause an actual packet transmission over the S3MII interface. This restriction on packet
transmissions calls for a delay in the packet transmission after device reset. An approximate delay of 2 ms
after reset should be enough to start packet transmissions.
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2.16 Initialization
2.16.1 Enabling the EMAC/MDIO Peripheral
When the device is powered on, the EMAC peripheral is disabled. Prior to EMAC-specific initialization, the
EMAC must be enabled; otherwise its registers cannot be written, and the reads will all return a value of
zero. The interface to be used (MII, RMII, GMII, or RGMII) is automatically selected at power-on reset,
based on the state of the MACSEL configuration pins.
EMAC/MDIO is enabled through the chip level module state control register 0 (MDCTL0) and module
status register 0 (MDSTAT0). For detailed information on the programming sequence, see the
EMAC peripheral, and the register values are reset to default. Module-specific initialization may proceed.
2.16.2 EMIC Module Initialization
The EMIC module is used for global interrupt enable, and to pace back-to-back interrupts using an
interrupt re-trigger count based on the peripheral clock (CPUCLK/6).
Note that although the EMIC module and the EMAC module have slightly different functions, in practice,
the type of maintenance performed on the EMIC module is more commonly conducted from the EMAC
module software (as opposed to the MDIO module).
The initialization of the EMIC module consists of two parts:
1. Configuration of the interrupt on the DSP.
2. Initialization of the EMIC module:
•
•
•
Setting the interrupt pace count delay and prescaler
Initializing the EMAC and MDIO modules
Enabling interrupts in the EW_INTCTL
Use the system's interrupt controller to map the EMAC interrupts to one of the CPU's interrupts. Once the
interrupt is mapped to a CPU interrupt, general masking and unmasking of the interrupt (to control
reentrancy) should be done at the chip level by manipulating the interrupt enable mask. The EMIC module
interrupt control register (EW_INTCTL) should only enable and disable interrupts from within the EMAC
interrupt service routine (ISR), as disabling and re-enabling the interrupt in EW_INTCTL also resets the
interrupt pace counter.
2.16.3 MDIO Module Initialization
The MDIO module initially configures and monitors one or more external PHY devices. Other than
initializing the software state machine (details on the MDIO state machine can be found in the IEEE 802.3
standard), the MDIO module only needs the MDIO engine enabled and the clock divider configured. To
set the clock divider, supply an MDIO clock of 1 MHz. As the peripheral clock is used as the base clock
(CPUclk/6), the divider can be set to 125 for a 750 MHz device. Slower MDIO clocks for slower CPU
frequencies are acceptable.
Both the state machine enable and the MDIO clock divider are controlled through the MDIO control
register (CONTROL). If none of the potentially connected PHYs require the access preamble, the
example of the code for initialization.
Example 4. MDIO Module Initialization Code
#define PCLK 125
...
/* Enable MDIO and setup divider */
MDIO_REGS->CONTROL = CSL_FMKT( MDIO_CONTROL_ENABLE, YES) |
CSL_FMK( MDIO_CONTROL_CLKDIV, PCLK ) ;
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If the MDIO module must operate on an interrupt basis, the interrupts can be enabled at this time using
the USERINTMASKSET register for register access and the USERPHYSELn register if a target PHY is
already known.
Once the MDIO state machine has been initialized and enabled, it starts polling all 32 PHY addresses on
the MDIO bus, looking for active PHYs. Since it can take up to 50 ms to read one register, the MDIO
module provides an accurate representation of all the PHYs available after a reasonable interval. Also, a
PHY can take up to 3 seconds to negotiate a link. Thus, it is advisable to run the MDIO software off a
time-based event rather than polling.
For more information on PHY control registers, see the PHY device documentation.
2.16.4 EMAC Module Initialization
The EMAC module sends and receives data packets over the network by maintaining up to 8 transmit and
receive descriptor queues. The EMAC module configuration must also be kept current based on the PHY
negotiation results returned from the MDIO module. Programming this module is the most time-consuming
aspect of developing an application or device driver for Ethernet.
A device drive should follow this initialization procedure to get the EMAC to the state where it is ready to
receive and send Ethernet packets. Some of these steps are not necessary when performed immediately
after device reset.
1. If enabled, clear the device interrupt enable in EW_INTCTL.
2. Clear the MACCONTROL, RXCONTROL, and TXCONTROL registers (not necessary immediately
after reset).
3. Initialize all 16 Head Descriptor Pointer registers (RXnHDP and TXnHDP) to 0.
4. Clear all 36 statistics registers by writing 0 (not necessary immediately after reset).
5. Initialize all 32 receive address RAM locations to 0. Set up the addresses to be matched to the eight
receive channels and the addresses to be filtered, through programming the MACINDEX,
MACADDRHI, and MACADDRLO registers.
6. Initialize the RXnFREEBUFFER, RXnFLOWTHRESH, and RXFILTERLOWTHRESH registers, if buffer
flow control is to be enabled. Program the FIFOCONTROL register if FIFO flow control is desired.
7. Most device drivers open with no multicast addresses, so clear the MACHASH1 and MACHASH2
registers.
8. Write the RXBUFFEROFFSET register value (typically zero).
9. Initially clear all unicast channels by writing FFh to the RXUNICASTCLEAR register. If unicast is
desired, it can be enabled now by writing the RXUNICASTSET register. Some drivers will default to
unicast on device open while others will not.
10. If you want to transfer jumbo frames, set the RXMAXLEN register to the maximum frame length you
want to be received.
11. Set up the RXMBPENABLE register with an initial configuration. The configuration is based on the
current receive filter settings of the device driver. Some drivers may enable things like broadcast and
multicast packets immediately, while others may not.
12. Set the appropriate configuration bits in the MACCONTROL register (do not set the GMIIEN bit yet).
13. Clear all unused channel interrupt bits by writing RXINTMASKCLEAR and TXINTMASKCLEAR.
14. Enable the receive and transmit channel interrupt bits in RXINTMASKSET and TXINTMASKSET for
the channels to be used, and enable the HOSTMASK and STATMASK bits using the
MACINTMASKSET register.
15. Initialize the receive and transmit descriptor list queues using the 8K descriptor memory block
contained in the CPPI buffer manager.
16. Prepare to receive by writing a pointer to the head of the receive buffer descriptor list to RXnHDP.
17. Enable the receive and transmit DMA controllers by setting the RXEN bit in the RXCONTROL register
and the TXEN bit in the TXCONTROL register. Then set the GMIIEN bit in MACCONTROL.
18. If the gigabit mode is desired (available only if using GMII or RGMII interface), set the GIG bit in the
MACCONTROL register.
19. When using RMII, release the interface logic from reset by clearing the RMII_RST field of the EMAC
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Configuration register (EMACCFG), found at device level.
20. Enable the device interrupt in EW_INTCTL.
2.17 Interrupt Support
2.17.1 EMAC Module Interrupt Events and Requests
The EMAC/MDIO generates 18 interrupt events, as follows:
•
•
•
•
TXPENDn: Transmit packet completion interrupt for transmit channels 7 through 0
RXPENDn: Receive packet completion interrupt for receive channels 7 through 0
STATPEND: Statistics interrupt
HOSTPEND: Host error interrupt
2.17.1.1 Transmit Packet Completion Interrupts
The transmit DMA engine has eight channels, and each channel has a corresponding interrupt
(TXPENDn). The transmit interrupts are level interrupts that remain asserted until cleared by the CPU.
Each of the eight transmit channel interrupts may be individually enabled by setting the appropriate bit in
the TXINTMASKSET register. Each of the eight transmit channel interrupts may be individually disabled
by clearing the appropriate bit in the TXINTMASKCLEAR register. The raw and masked transmit interrupt
status may be read by reading the TXINTSTATRAW and TXINTSTATMASKED registers, respectively.
When the EMAC completes the transmission of a packet, the EMAC issues an interrupt to the CPU by
writing the packet's last buffer descriptor address to the appropriate channel queue's TX completion
pointer located in the state RAM block. The write generates the interrupt when enabled by the interrupt
mask, regardless of the value written.
Upon interrupt reception, the CPU processes one or more packets from the buffer chain and then
acknowledges an interrupt by writing the address of the last buffer descriptor processed to the queue's
associated TX completion pointer in the transmit DMA state RAM.
The data written by the host (buffer descriptor address of the last processed buffer) is compared to the
data in the register written by the EMAC port (address of last buffer descriptor used by the EMAC). If the
two values are not equal, indicating that the EMAC has transmitted more packets than the CPU has
processed interrupts for, then the transmit packet completion interrupt signal remains asserted. If the two
values are equal, indicating that the host has processed all packets that the EMAC has transferred, then
the pending interrupt is cleared. Reading the TXnCP register displays the value that the EMAC is
expecting.
The EMAC write to the completion pointer stores the value in the state RAM. The CPU written value does
not change the register value. The host-written value is compared to the register content, which was
written by the EMAC. If the two values are equal, then the interrupt is removed; otherwise the interrupt
remains asserted. The host may process multiple packets prior to acknowledging an interrupt, or the host
may acknowledge interrupts for every packet.
2.17.1.2 Receive Packet Completion Interrupts
The receive DMA engine has eight channels, and each channel has a corresponding interrupt
(RXPENDn). The receive interrupts are level interrupts that remain asserted until cleared by the CPU.
Each of the eight receive channel interrupts may be individually enabled by setting the appropriate bit in
the RXINTMASKSET register. Each of the eight receive channel interrupts may be individually disabled by
clearing the appropriate bit in the RXINTMASKCLEAR register. The raw and masked receive interrupt
status may be read by reading the RXINTSTATRAW and RXINTSTATMASKED registers, respectively.
When the EMAC completes a packet reception, the EMAC issues an interrupt to the CPU by writing the
packet's last buffer descriptor address to the appropriate channel queue's RX completion pointer located
in the state RAM block. The write generates the interrupt when enabled by the interrupt mask, regardless
of the value written.
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Upon interrupt reception, the CPU processes one or more packets from the buffer chain and then
acknowledges one or more interrupt(s) by writing the address of the last buffer descriptor processed to the
queue's associated RX completion pointer in the receive DMA state RAM.
The data written by the host (buffer descriptor address of the last processed buffer) is compared to the
data in the register written by the EMAC (address of last buffer descriptor used by the EMAC). If the two
values are not equal, indicating that the EMAC has received more packets than the CPU has processed
interrupts for, the receive packet completion interrupt signal remains asserted. If the two values are equal,
indicating that the host has processed all packets that the EMAC has received, the pending interrupt is
de-asserted. Reading the RXnCP register displays the value that the EMAC is expecting.
The EMAC write to the completion pointer stores the value in the state RAM. The CPU written value does
not change the register value. The host-written value is compared to the register content, which was
written by the EMAC. If the two values are equal, then the interrupt is removed; otherwise the interrupt
remains asserted. The host may process multiple packets prior to acknowledging an interrupt, or the host
may acknowledge interrupts for every packet.
2.17.1.3 Statistics Interrupt
The statistics level interrupt (STATPEND) is issued when any statistics value is greater than or equal to
8000 0000h, if it has been enabled by the STATMASK bit in the MACINTMASKSET register. The statistics
interrupt is removed by writing to decrement any statistics value greater than 8000 0000h. The interrupt
remains asserted as long as the most-significant-bit of any statistics value is set.
2.17.1.4 Host Error Interrupt
The host error interrupt (HOSTPEND) is issued, if enabled, under error conditions due to the handling of
buffer descriptors detected during transmit or receive DMA transactions. The failure of the software
application to supply properly formatted buffer descriptors results in this error. The error bit can only be
cleared by resetting the EMAC module in hardware.
The host error interrupt is enabled by setting the HOSTMASK bit in the MACINTMASKSET register. The
host error interrupt is disabled by clearing the appropriate bit in the MACINTMASKCLEAR register. The
raw and masked host error interrupt status may be read by reading the MACINTSTATRAW and
MACINTSTATMASKED registers, respectively.
Transmit host error conditions include:
•
•
•
•
•
•
SOP error
Ownership bit not set in SOP buffer
Zero next buffer descriptor pointer without EOP
Zero buffer pointer
Zero buffer length
Packet length error
Receive host error conditions include:
•
•
Ownership bit not set in input buffer
Zero buffer pointer
2.17.2 MDIO Module Interrupt Events and Requests
The MDIO module generates two interrupt events, as follows:
•
•
LINKINT: Serial interface link change interrupt. Indicates a change in the state of the PHY link.
USERINT: Serial interface user command event complete interrupt.
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2.17.2.1 Link Change Interrupt
The MDIO module asserts a link change interrupt (LINKINT) if there is a change in the link state of the
PHY corresponding to the address in the PHYADRMON bits in the USERPHYSELn register, and if the
LINKINTENB bit is also set in USERPHYSELn. This interrupt event is also captured in the LINKINTRAW
bits of the LINKINTRAW register. The LINKINTRAW bits 0 and 1 correspond to USERPHYSEL0 and
USERPHYSEL1, respectively.
When the interrupt is enabled and generated, the corresponding bit is also set in the LINKINTMASKED
register. The interrupt is cleared by writing back the same bit to LINKINTMASKED (write to clear).
2.17.2.2 User Access Completion Interrupt
A user access completion interrupt (USERINT) is asserted when the GO bit in one of the USERACCESSn
registers transitions from 1 to 0 (indicating completion of a user access) and the bit in the
USERINTMASKSET register corresponding to USERACCESS0 or USERACCESS1 is set. This interrupt
event is also captured in bits 0 and 1 of the USERINTRAW register. USERINTRAW bits 0 and bit 1
correspond to USERACCESS0 and USERACCESS1, respectively.
When the interrupt is enabled and generated, the corresponding USERINTMASKED bit is also set in the
USERINTMASKED register. The interrupt is cleared by writing back the same bit to USERINTMASKED
(write to clear).
2.17.3 Proper Interrupt Processing
All the interrupts signaled from the EMAC and MDIO modules are level-driven. If they remain active, their
level remains constant. However, the CPU core requires edge-triggered interrupts. To properly convert the
level-driven interrupt signal to an edge-triggered signal, the application software must use the interrupt
control logic of the EMIC module.
For safe interrupt processing, the software application should disable interrupts using the EMIC module
interrupt control register (EW_INTCTL) upon entry to the ISR, and re-enable them upon leaving the ISR.
2.17.4 Interrupt Multiplexing
The EMIC module combines different interrupt signals from both the EMAC and MDIO modules and
generates a single interrupt signal that is wired to the CPU interrupt controller.
Once this interrupt is generated, the reason for the interrupt can be read from the MACINVECTOR
register located in the EMAC memory map. MACINVECTOR combines the status of the following 20
interrupt signals: TXPENDn, RXPENDn, STATPEND, HOSTPEND, LINKINT, and USERINT.
The EMAC and MDIO interrupts are combined within the EMIC module and mapped to system events 70
and 71 through the use of the enhanced interrupt selector within the C64x+ core. For more details, see the
2.18 Power Management
The power saver module integrated in this device allows the clock for different peripherals to be shut down
when that peripheral is not being used. For more information on the power conservation modes available
for the EMAC/MDIO peripheral, see the TMS320TCI6486 Communications Infrastructure Digital Signal
2.19 Emulation Considerations
EMAC emulation control is implemented for compatibility with other peripherals. The SOFT and FREE bits
from the EMCONTROL register allow EMAC operation to be suspended.
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When the emulation suspend state is entered, the EMAC will stop processing receive and transmit frames
at the next frame boundary. Any frame currently in reception or transmission will be completed normally
without suspension. For transmission, any complete or partial frame in the transmit cell FIFO will be
transmitted. For receive, frames that are detected by the EMAC after the suspend state is entered are
ignored. No statistics will be kept for ignored frames.
Table 16 shows how the SOFT and FREE bits affect the operation of the emulation suspend.
Table 16. Emulation Control
SOFT
FREE
Description
0
1
X
0
0
1
Normal operation
Emulation suspend
Normal operation
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EMIC Module Registers
3
EMIC Module Registers
3.1 EW_INTCTL Registers
reside in the configuration space of the respective Ethernet wrappers. This register controls generation of
MACTXINT, MACRXINT, and MACINT interrupts for each core.
The interrupts are classified into 3 groups:
•
Common interrupts:
–
–
–
–
MDIO_USER
MDIO_LINT
STAT
HOST
•
Transmit interrupts:
TX0 through TX7
Receive interrupts:
RX0 through RX7
Generation of MACINTX is conditional on the following:
–
•
–
•
•
At least one of the pulse interrupts in the common group is enabled.
At least one of the enabled pulse interrupts in the common group is asserted by EMAC or MDIO.
Generation of MACTXINTX is conditional on the following:
•
•
At least one of the pulse interrupts in the transmit group is enabled.
At least one of the enabled pulse interrupts in the transmit group is asserted by EMAC.
Generation of MACRXINTX is conditional on the following:
•
•
At least one of the pulse interrupts in the receive group is enabled.
At least one of the enabled pulse interrupts in the receive group is asserted by EMAC.
Figure 23. EW_INTCTL Register
31
24
Reserved
0000 0000
23
22
21
20
19
18
17
16
RX7
RX6
RX5
RX4
RX3
RX2
RX1
RX0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
15
14
13
12
11
10
9
8
TX7
TX6
TX5
TX4
TX3
TX2
TX1
TX0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
7
5
4
3
2
1
0
Reserved
0
Reserved
000
MDIO_USER
R/W-0
MDIO_LINT
R/W-0
STAT
R/W-0
HOST
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
3.2 RPIC Registers
3.2.1
RPCFG Registers
There are eight RPCFG registers (RPCFG0 through RPCFG7), one per receive event. This register
configuration is common to all C64x+ megamodules. The RPCFG register details are shown in Figure 24
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16
Figure 24. RPCFG Register
31
28
27
Reserved
0000
TIME_CFG
R/W-0000 0000
15
8
7
4
3
2
1
0
CNT_CFG
Reserved
0000
TU
CU
TR
CR
R/W-0000 0000
R/W-0 R/W-0 R/W-0 R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 17. RPCFG Register Field Descriptions
Bit
Field
Value Description
31-28 Reserved
27-16 TIME_CFG
Reserved
Time delay configuration value
Divide by N configuration value
Reserved
15-8
7-4
3
CNT_CFG
Reserved
TU
Write-only bit; reads return 0
N/A
0
1
Enables writes to TIME_CFG
Write-only bit; reads return 0
N/A
2
1
0
CU
TR
CR
0
1
Enables writes to CNT_CFG
Write-only bit; reads return 0
N/A
0
1
Resets the timer counter
Write-only bit; reads return 0
N/A
0
1
Resets the divide by N count
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EMIC Module Registers
3.2.2
RPSTAT Registers
There are eight RPSTAT registers (RPSTAT0 thru RPSTAT7), one per receive event. This register
configuration is common to all C64x+ megamodules. The RPSTAT register details are shown in Figure 25
Figure 25. RPSTAT Register
31
15
28
27
16
Reserved
0000
TIME
R-0000 0000
8
7
4
3
2
1
0
CNT
R-0000 0000
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Reserved
0000
TIM_SM
R-00
DIV_SM
R-00
Table 18. RPSTAT Register Field Descriptions
Bit
Field
Value Description
31-28 Reserved
27-16 TIME
Reserved
Current time delay value
Current divide by N value
Reserved
15-8
7-4
CNT
Reserved
TIM_SM
3-2
Time delay SM
00
01
10
11
Time delay SM in WAITING state
Time delay SM in DELAY state
Time delay SM in OUTPUT state
Reserved
1-0
DIV_SM
Divide by N SM
00
01
10
11
Divide by N SM in WAITING state
Divide by N SM in DELAY state
Divide by N SM in OUTPUT state
Reserved
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3.3 TPIC Registers
3.3.1
TPCFG Registers
There are eight TPCFG registers (TPCFG0 through TPCFG7), one per transmit event. This register
configuration is common to all C64x+ megamodules. The TPCFG register details are shown in Figure 26
Figure 26. TPCFG Register
31
15
28
27
16
Reserved
0000
TIME_CFG
R/W-0000 0000
8
7
4
3
2
1
0
CNT_CFG
Reserved
0000
TU
CU
TR
CR
R/W-0000 0000
R/W-0 R/W-0 R/W-0 R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 19. TPCFG Register Field Descriptions
Bit
Field
Value Description
31-28 Reserved
27-16 TIME_CFG
Reserved
Time delay configuration value
Divide by N configuration value
Reserved
15-8
7-4
3
CNT_CFG
Reserved
TU
Write-only bit; reads return 0
N/A
0
1
Enables writes to TIME_CFG
Write-only bit; reads return 0
N/A
2
1
0
CU
TR
CR
0
1
Enables writes to CNT_CFG
Write-only bit; reads return 0
N/A
0
1
Resets the timer counter
Write-only bit; reads return 0
N/A
0
1
Resets the divide by N count
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EMIC Module Registers
3.3.2
TPSTAT Registers
There are eight TPSTAT registers (TPSTAT0 through TPSTAT7), one per transmit event. This register
configuration is common to all C64x+mega modules. The TPSTAT register details are shown in Figure 27
Figure 27. TPSTAT Register
31
15
28
27
16
Reserved
0000
TIME
R-0000 0000
8
7
4
3
2
1
0
CNT
R-0000 0000
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Reserved
0000
TIM_SM
R-00
DIV_SM
R-00
Table 20. TPSTAT Register Field Descriptions
Bit
Field
Value Description
31-28 Reserved
27-16 TIME
Reserved
Current time delay value
Current divide by N value
Reserved
15-8
7-4
CNT
Reserved
TIM_SM
3-2
Time delay SM
00
01
10
11
Time delay SM in WAITING state
Time delay SM in DELAY state
Time delay SM in OUTPUT state
Reserved
1-0
DIV_SM
Divide by N SM
00
01
10
11
Divide by N SM in WAITING state
Divide by N SM in DELAY state
Divide by N SM in OUTPUT state
Reserved
3.4 Prescalar Configuration Register (PSCFG)
There is a single PSCFG register for the wrapper. It contains the reload value for the prescalar
Figure 28. Prescalar Configuration Register (PSCFG)
31
15
16
0
Reserved
0000 0000
PRESCALE_CFG
R/W-0000 0000
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
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4
MDIO Registers
4.1 Introduction
Table 21 lists the memory-mapped registers for the Management Data Input/Output (MDIO). For the
memory address of these registers, see the TMS320TCI6486 Communications Infrastructure Digital Signal
Table 21. Management Data Input/Output (MDIO) Registers
Offset
0h
Acronym
Register Description
See
VERSION
MDIO Version Register
4h
CONTROL
ALIVE
MDIO Control Register
8h
PHY Alive Status register
Ch
LINK
PHY Link Status Register
10h
14h
20h
LINKINTRAW
LINKINTMASKED
USERINTRAW
MDIO Link Status Change Interrupt (Unmasked) Register
MDIO Link Status Change Interrupt (Masked) Register
MDIO User Command Complete Interrupt (Unmasked)
Register
24h
28h
2Ch
USERINTMASKED
USERINTMASKSET
USERINTMASKCLEAR
MDIO User Command Complete Interrupt (Masked) Register
MDIO User Command Complete Interrupt Mask Set Register
MDIO User Command Complete Interrupt Mask Clear
Register
80h
84h
88h
8Ch
USERACCESS0
USERPHYSEL0
USERACCESS1
USERPHYSEL1
MDIO User Access Register 0
MDIO User PHY Select Register 0
MDIO User Access Register 1
MDIO User PHY Select Register 1
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MDIO Registers
4.2 MDIO Version Register (VERSION)
Figure 29. MDIO Version Register (VERSION)
31
16
0
MODID
R-7
15
8
7
REVMAJ
R-1
REVMIN
R-3
LEGEND: R = Read only; R/W = Read/Write; -n = value after reset
Table 22. MDIO Version Register (VERSION) Field Descriptions
Bit
Field
Value Description
31-16 MODID
Identifies the type of peripheral
15-8
7-0
REVMAJ
REVMIN
Management Interface Module major revision value
Management Interface Module minor revision value
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4.3 MDIO Control Register (CONTROL)
Figure 30. MDIO Control Register (CONTROL)
31
30
29
28
24
23
21
20
19
18
17
16
FAULT
ENB
IDLE ENABLE Reserved
HIGHEST_USER_CHANNEL
R-1
Reserved
R-0
PREAMBLE
R/W-0
FAULT
R/WC-0
Reserved
R-1
15
R/W-0
R-0
R/W-0
R-0
0
CLKDIV
R/W-255
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 23. MDIO Control Register (CONTROL) Field Descriptions
Bit
Field
Value Description
31
IDLE
State machine IDLE status bit
0
1
State machine is not in idle state
State machine is in idle state
30
ENABLE
State machine enable control bit. If the MDIO state machine is active at the time it is
disabled, it will complete the current operation before halting and setting the idle bit.
0
1
0
Disables the MDIO state machine
Enable the MDIO state machine
Reserved
29
Reserved
28-24 HIGHEST_USER_CHANNEL
23-21 Reserved
Highest user channel that is available in the module. It is currently set to 1. This
implies that MDIOUserAccess1 is the highest available user access channel.
0
Reserved
20
PREAMBLE
Preamble disable
0
1
Standard MDIO preamble is used
Disables this device from sending MDIO frame preambles
19
FAULT
Fault indicator. This bit is set to 1 if the MDIO pins fail to read back what the device
is driving onto them. This indicates a physical layer fault and the module state
machine is reset. Writing a 1 to it clears this bit.
0
1
No failure
Physical layer fault; the MDIO state machine is reset
18
FAULTENB
Fault detect enable. This bit has to be set to 1 to enable the physical layer fault
detection.
0
1
0
Disables the physical layer fault detection
Enables the physical layer fault detection
Reserved
17-16 Reserved
15-0
CLKDIV
Clock Divider bits. This field specifies the division ratio between peripheral bus
peripheral clock and the frequency of MDCLK. MDCLK is disabled when CLKDIV is
set to 0. MDCLK frequency = peripheral clock frequency/(CLKDIV + 1).
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MDIO Registers
4.4 PHY Acknowledge Status Register (ALIVE)
Figure 31. PHY Acknowledge Status Register (ALIVE)
31
15
16
0
ALIVE
R/WC-0
ALIVE
R/WC-0
LEGEND: R/W = Read/Write; R/WC = Read/Write 1 to clear; -n = value after reset
Table 24. PHY Acknowledge Status Register (ALIVE) Field Descriptions
Bit
Field
Value Description
31-0
ALIVE
MDIO Alive bits. Each of the 32 bits of this register is set if the most recent access to the PHY with
address corresponding to the register bit number was acknowledged by the PHY; the bit is reset if
the PHY fails to acknowledge the access. Both the user and polling accesses to a PHY will cause
the corresponding alive bit to be updated. The alive bits are only meant to be used to give an
indication of the presence or not of a PHY with the corresponding address. Writing a 1 to any bit
will clear it, writing a 0 has no effect.
0
1
The PHY fails to acknowledge the access.
The most recent access to the PHY with an address corresponding to the register bit number was
acknowledged by the PHY.
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4.5 PHY Link Status Register (LINK)
Figure 32. PHY Link Status Register (LINK)
31
16
0
LINK
R-0
15
LINK
R-0
LEGEND: R = Read only; -n = value after reset
Table 25. PHY Link Status Register (LINK) Field Descriptions
Bit
Field
Value Description
31-0
LINK
MDIO Link state bits. This register is updated after a read of the Generic Status Register of a PHY.
The bit is set if the PHY with the corresponding address has link and the PHY acknowledges the
read transaction. The bit is reset if the PHY indicates it does not have a link or fails to acknowledge
the read transaction. Writes to the register have no effect.
0
1
The PHY indicates it does not have a link or fails to acknowledge the read transaction
The PHY with the corresponding address has a link and the PHY acknowledges the read
transaction
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MDIO Registers
4.6 MDIO Link Status Change Interrupt (Unmasked) Register (LINKINTRAW)
Figure 33. MDIO Link Status Change Interrupt (Unmasked) Register (LINKINTRAW)
31
15
16
0
Reserved
R-0
2
1
Reserved
R-0
LINKINTRAW
R/WC-0
LEGEND: R = Read only; R/WC = Read/Write 1 to clear; -n = value after reset
Table 26. MDIO Link Status Change Interrupt (Unmasked) Register (LINKINTRAW) Field
Descriptions
Bit
31-2
1-0
Field
Value Description
Reserved
0
Reserved
LINKINTRAW
MDIO Link change event, raw value. When asserted, a bit indicates that there was an MDIO link
change event (a change in the LINK register) corresponding to the PHY address in the
USERPHYSEL register. LINKINTRAW[0] and LINKINTRAW[1] correspond to USERPHYSEL0 and
USERPHYSEL1, respectively. Writing a 1 will clear the event and writing 0 has no effect.
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4.7 MDIO Link Status Change Interrupt (Masked) Register (LINKINTMASKED)
Figure 34. MDIO Link Status Change Interrupt (Masked) Register (LINKINTMASKED)
31
15
16
Reserved
R-0
2
1
0
LINKINT
MASKED
Reserved
R-0
R/WC-0
LEGEND: R = Read only; R/WC = Read/Write 1 to clear; -n = value after reset
Table 27. MDIO Link Status Change Interrupt (Masked) Register (LINKINTMASKED) Field
Descriptions
Bit
31-2
1-0
Field
Value Description
Reserved
0
Reserved
LINKINTMASKED
MDIO Link change interrupt, masked value. hen asserted, a bit indicates that there was an MDIO
link change event (a change in the LINK register) corresponding to the PHY address in the
USERPHYSEL register and the corresponding LINKINTENB bit was set. LINKINTRAW[0] and
LINKINTRAW[1] correspond to USERPHYSEL0 and USERPHYSEL1, respectively. Writing a 1 will
clear the event and writing 0 has no effect.
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MDIO Registers
4.8 MDIO User Command Complete Interrupt (Unmasked) Register (USERINTRAW)
The MDIO user command complete interrupt (unmasked) register (USERINTRAW) is shown in Figure 35
Figure 35. MDIO User Command Complete Interrupt (Unmasked) Register (USERINTRAW)
31
15
16
Reserved
R-0
2
1
0
Reserved
R-0
LEGEND: R = Read only; R/WC = Read/Write 1 to clear; -n = value after reset
USERINTRAW
R/WC-0
Table 28. MDIO User Command Complete Interrupt (Unmasked) Register (USERINTRAW) Field
Descriptions
Bit
31-2
1-0
Field
Value Description
Reserved
USERINTRAW
0
Reserved
MDIO User command complete event bits. When asserted, a bit indicates that the previously
scheduled PHY read or write command using that particular USERACCESS register has
completed. Writing a 1 will clear the event and writing 0 has no effect.
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4.9 MDIO User Command Complete Interrupt (Masked) Register (USERINTMASKED)
The MDIO user command complete interrupt (masked) register (USERINTMASKED) is shown in
Figure 36. MDIO User Command Complete Interrupt (Masked) Register (USERINTMASKED)
31
15
16
0
Reserved
R-0
2
1
USERINT
MASKED
Reserved
R-0
R/WC-0
LEGEND: R = Read only; R/WC = Read/Write 1 to clear; -n = value after reset
Table 29. MDIO User Command Complete Interrupt (Masked) Register (USERINTMASKED) Field
Descriptions
Bit
31-2
1-0
Field
Value Description
Reserved
0
Reserved
USERINTMASKED
Masked value of MDIO User command complete interrupt. When asserted, a bit indicates that
the previously scheduled PHY read or write command using that particular USERACCESS
register has completed and the corresponding USERINTMASKSET bit is set to 1. Writing a 1
will clear the interrupt and writing 0 has no effect.
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MDIO Registers
4.10 MDIO User Command Complete Interrupt Mask Set Register (USERINTMASKSET)
The MDIO user command complete interrupt mask set register (USERINTMASKSET) is shown in
Figure 37. MDIO User Command Complete Interrupt Mask Set Register (USERINTMASKSET)
31
15
16
Reserved
R-0
2
1
0
USERINT
MASKSET
Reserved
R-0
R/WC-0
LEGEND: R = Read only; R/WC = Read/Write 1 to clear; -n = value after reset
Table 30. MDIO User Command Complete Interrupt Mask Set Register (USERINTMASKSET) Field
Descriptions
Bit
31-2
1-0
Field
Value Description
Reserved
0
Reserved
USERINTMASKSET
MDIO user interrupt mask set for USERINTMASKED[1:0] respectively. Setting a bit to 1 will
enable MDIO user command complete interrupts for that particular USERACCESS register.
MDIO user interrupt for a particular USERACCESS register is disabled if the corresponding bit
is 0. Writing a 0 to this register has no effect.
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4.11 MDIO User Command Complete Interrupt Mask Clear Register
(USERINTMASKCLEAR)
The MDIO user command complete interrupt mask clear register (USERINTMASKCLEAR) is shown in
Figure 38. MDIO User Command Complete Interrupt Mask Clear Register (USERINTMASKCLEAR)
31
15
16
Reserved
R-0
2
1
0
USERINT
MASKCLEAR
Reserved
R-0
R/WC-0
LEGEND: R = Read only; R/WC = Read/Write 1 to clear; -n = value after reset
Table 31. MDIO User Command Complete Interrupt Mask Clear Register (USERINTMASKCLEAR)
Field Descriptions
Bit
31-2
1-0
Field
Value Description
Reserved
0
Reserved
USERINTMASKCLEAR
MDIO user command complete interrupt mask clear for USERINTMASKED[1:0]
respectively. Setting a bit to 1 will disable further user command complete interrupts for
that particular USERACCESS register. Writing a 0 to this register has no effect.
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MDIO Registers
4.12 MDIO User Access Register 0 (USERACCESS0)
Figure 39. MDIO User Access Register 0 (USERACCESS0)
31
GO
30
29
28
26
25
21
20
16
0
WRITE
R/W-0
ACK
Reserved
R-0
REGADR
R/W-0
PHYADR
R/W-0
R/WS-0
R/W-0
15
DATA
R/W-0
LEGEND: R = Read only; R/W = Read/Write; R/WS = Read/Write 1 to set; -n = value after reset
Table 32. MDIO User Access Register 0 (USERACCESS0) Field Descriptions
Bit
Field
Value Description
31
GO
Go bit. Writing a 1 to this bit causes the MDIO state machine to perform an MDIO access when it is
convenient for it to do so; this is not an instantaneous process. Writing a 0 to this bit has no effect.
This bit is writeable only if the MDIO state machine is enabled. This bit will self clear when the
requested access has been completed. Any writes to the USERACCESS0 register are blocked
when the GO bit is 1.
30
29
WRITE
ACK
Write enable bit. Setting this bit to a 1 causes the MDIO transaction to be a register write, otherwise
it is a register read.
0
1
The user command is a read operation
The user command is a write operation
Acknowledge bit. This bit is set if the PHY acknowledged the read transaction.
Reserved
28-26 Reserved
25-21 REGADR
20-16 PHYADR
0
Register address bits. This field specifies the PHY register to be accessed for this transaction.
PHY address bits. This field specifies the PHY to be accessed for this transaction.
15-0
DATA
User data bits. These bits specify the data value read from or to be written to the specified PHY
register.
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4.13 MDIO User PHY Select Register 0 (USERPHYSEL0)
Figure 40. MDIO User PHY Select Register 0 (USERPHYSEL0)
31
16
Reserved
R-0
15
8
7
6
5
4
0
Reserved
R-0
LINKSEL
R/W-0
LINKINTENB
R/W-0
Reserved
R-0
PHYADRMON
R/W-0
LEGEND: R = Read only; R/W = Read/Write; -n = value after reset
Table 33. MDIO User PHY Select Register 0 (USERPHYSEL0) Field Descriptions
Bit
31-8
7
Field
Value Description
Reserved
LINKSEL
0
Reserved
Link status determination select bit. Default value is 0, which implies that the link status is
determined by the MDIO state machine. This is the only option supported on this device.
6
LINKINTENB
Link change interrupt enable. Set to 1 to enable link change status interrupts for PHY address
specified in PHYADRMON. Link change interrupts are disabled if this bit is set to 0.
0
1
0
Link change interrupts are disabled
Link change status interrupts for PHY address specified in PHYADDRMON bits are enabled
Reserved
5
Reserved
4-0
PHYADRMON
PHY address whose link status is to be monitored.
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MDIO Registers
4.14 MDIO User Access Register 1 (USERACCESS1)
Figure 41. MDIO User Access Register 1 (USERACCESS1)
31
GO
30
29
28
26
25
21
20
16
0
WRITE
R/W-0
ACK
Reserved
R-0
REGADR
R/W-0
PHYADR
R/W-0
R/WS-0
R/W-0
15
DATA
R/W-0
LEGEND: R = Read only; R/W = Read/Write; R/WS = Read/Write 1 to set; -n = value after reset
Table 34. MDIO User Access Register 1 (USERACCESS1) Field Descriptions
Bit
Field
Value Description
31
GO
Go bit. Writing a 1 to this bit causes the MDIO state machine to perform an MDIO access when it is
convenient for it to do so, this is not an instantaneous process. Writing a 0 to this bit has no effect.
This bit is write-able only if the MDIO state machine is enabled. This bit will self clear when the
requested access has been completed. Any writes to the USERACCESS0 register are blocked
when the go bit is 1.
30
29
WRITE
ACK
Write enable bit. Setting this bit to a 1 causes the MDIO transaction to be a register write, otherwise
it is a register read.
0
1
The user command is a read operation
The user command is a write operation
Acknowledge bit. This bit is set if the PHY acknowledged the read transaction.
Reserved
28-26 Reserved
25-21 REGADR
20-16 PHYADR
0
Register address bits. This field specifies the PHY register to be accessed for this transaction.
PHY address bits. This field specifies the PHY to be accessed for this transaction.
15-0
DATA
User data bits. These bits specify the data value read from or to be written to the specified PHY
register.
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4.15 MDIO User PHY Select Register 1 (USERPHYSEL1)
Figure 42. MDIO User PHY Select Register 1 (USERPHYSEL1)
31
16
Reserved
R-0
15
8
7
6
5
4
0
Reserved
R-0
LINKSEL
R/W-0
LINKINTENB
R/W-0
Reserved
R-0
PHYADRMON
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 35. MDIO User PHY Select Register 1 (USERPHYSEL1) Field Descriptions
Bit
31-8
7
Field
Value Description
Reserved
LINKSEL
0
Reserved
Link status determination select bit. Default value is 0, which implies that the link status is
determined by the MDIO state machine. This is the only option supported on this device.
6
LINKINTENB
Link change interrupt enable. Set to 1 to enable link change status interrupts for PHY address
specified in PHYADRMON. Link change interrupts are disabled if this bit is set to 0.
0
1
0
Link change interrupts are disabled
Link change status interrupts for PHY address specified in PHYADDRMON bits are enabled
Reserved
5
Reserved
4-0
PHYADRMON
PHY address whose link status is to be monitored.
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EMAC Port Registers
5
EMAC Port Registers
Table 36 lists the memory-mapped registers for the Ethernet Media Access Controller (EMAC). For the
memory address of these registers, see the TMS320TCI6486 Communications Infrastructure Digital Signal
Table 36. Ethernet Media Access Controller (EMAC) Registers
Offset
0h
Acronym
Register Description
See
TXIDVER
Transmit Identification and Version Register
Transmit Control Register
4h
TXCONTROL
8h
TXTEARDOWN
RXIDVER
Transmit Teardown Register
10h
14h
18h
80h
84h
88h
8Ch
90h
94h
A0h
A4h
A8h
ACh
B0h
B4h
B8h
BCh
100h
Receive Identification and Version Register
Receive Control Register
RXCONTROL
RXTEARDOWN
TXINTSTATRAW
TXINTSTATMASKED
TXINTMASKSET
TXINTMASKCLEAR
MACINVECTOR
MACEOIVECTOR
RXINTSTATRAW
RXINTSTATMASKED
RXINTMASKSET
RXINTMASKCLEAR
MACINTSTATRAW
MACINTSTATMASKED
MACINTMASKSET
MACINTMASKCLEAR
RXMBPENABLE
Receive Teardown Register
Transmit Interrupt Status (Unmasked) Register
Transmit Interrupt Status (Masked) Register
Transmit Interrupt Mask Set Register
Transmit Interrupt Clear Register
MAC Input Vector Register
MAC End-of-Interrupt Vector Register
Receive Interrupt Status (Unmasked) Register
Receive Interrupt Status (Masked) Register
Receive Interrupt Mask Set Register
Receive Interrupt Mask Clear Register
MAC Interrupt Status (Unmasked) Register
MAC Interrupt Status (Masked) Register
MAC Interrupt Mask Set Register
MAC Interrupt Mask Clear Register
Receive Multicast/Broadcast/Promiscuous Channel Enable
Register
104h
108h
10Ch
110h
114h
120h
124h
128h
12Ch
130h
134h
138h
13Ch
140h
144h
148h
14Ch
150h
154h
158h
RXUNICASTSET
Receive Unicast Enable Set Register
RXUNICASTCLEAR
RXMAXLEN
Receive Unicast Clear Register
Receive Maximum Length Register
RXBUFFEROFFSET
RXFILTERLOWTHRESH
RX0FLOWTHRESH
RX1FLOWTHRESH
RX2FLOWTHRESH
RX3FLOWTHRESH
RX4FLOWTHRESH
RX5FLOWTHRESH
RX6FLOWTHRESH
RX7FLOWTHRESH
RX0FREEBUFFER
RX1FREEBUFFER
RX2FREEBUFFER
RX3FREEBUFFER
RX4FREEBUFFER
RX5FREEBUFFER
RX6FREEBUFFER
Receive Buffer Offset Register
Receive Filter Low Priority Frame Threshold Register
Receive Channel 0 Flow Control Threshold Register
Receive Channel 1 Flow Control Threshold Register
Receive Channel 2 Flow Control Threshold Register
Receive Channel 3 Flow Control Threshold Register
Receive Channel 4 Flow Control Threshold Register
Receive Channel 5 Flow Control Threshold Register
Receive Channel 6 Flow Control Threshold Register
Receive Channel 7 Flow Control Threshold Register
Receive Channel 0 Free Buffer Count Register
Receive Channel 1 Free Buffer Count Register
Receive Channel 2 Free Buffer Count Register
Receive Channel 3 Free Buffer Count Register
Receive Channel 4 Free Buffer Count Register
Receive Channel 5 Free Buffer Count Register
Receive Channel 6 Free Buffer Count Register
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Table 36. Ethernet Media Access Controller (EMAC) Registers (continued)
Offset
15Ch
160h
164h
168h
16Ch
170h
174h
1D0h
1D4h
1D8h
1DCh
1E0h
1E4h
1E8h
1ECh
500h
Acronym
Register Description
See
RX7FREEBUFFER
MACCONTROL
MACSTATUS
EMCONTROL
FIFOCONTROL
MACCONFIG
SOFTRESET
MACSRCADDRLO
MACSRCADDRHI
MACHASH1
Receive Channel 7 Free Buffer Count Register
MAC Control Register
MAC Status Register
Emulation Control Register
FIFO Control Register
MAC Configuration Register
Soft Reset Register
MAC Source Address Low Bytes Register
MAC Source Address High Bytes Register
MAC Hash Address Register 1
MAC Hash Address Register 2
Back Off Test Register
MACHASH2
BOFFTEST
TPACETEST
RXPAUSE
Transmit Pacing Algorithm Test Register
Receive Pause Timer Register
Transmit Pause Timer Register
TXPAUSE
MACADDRLO
MAC Address Low Bytes Register, Used in Receive Address
Matching
504h
MACADDRHI
MAC Address High Bytes Register, Used in Receive Address
Matching
508h
600h
604h
608h
60Ch
610h
614h
618h
61Ch
620h
624h
628h
62Ch
630h
634h
638h
63Ch
640h
MACINDEX
TX0HDP
TX1HDP
TX2HDP
TX3HDP
TX4HDP
TX5HDP
TX6HDP
TX7HDP
RX0HDP
RX1HDP
RX2HDP
RX3HDP
RX4HDP
RX5HDP
RX6HDP
RX7HDP
TX0CP
MAC Index Register
Transmit Channel 0 DMA Head Descriptor Pointer Register
Transmit Channel 1 DMA Head Descriptor Pointer Register
Transmit Channel 2 DMA Head Descriptor Pointer Register
Transmit Channel 3 DMA Head Descriptor Pointer Register
Transmit Channel 4 DMA Head Descriptor Pointer Register
Transmit Channel 5 DMA Head Descriptor Pointer Register
Transmit Channel 6 DMA Head Descriptor Pointer Register
Transmit Channel 7 DMA Head Descriptor Pointer Register
Receive Channel 0 DMA Head Descriptor Pointer Register
Receive Channel 1 DMA Head Descriptor Pointer Register
Receive Channel 2 DMA Head Descriptor Pointer Register
Receive Channel 3 DMA Head Descriptor Pointer Register
Receive Channel 4 DMA Head Descriptor Pointer Register
Receive Channel 5 DMA Head Descriptor Pointer Register
Receive Channel 6 DMA Head Descriptor Pointer Register
Receive Channel 7 DMA Head Descriptor Pointer Register
Transmit Channel 0 Completion Pointer (Interrupt
Acknowledge) Register
644h
648h
64Ch
650h
654h
658h
TX1CP
TX2CP
TX3CP
TX4CP
TX5CP
TX6CP
Transmit Channel 1 Completion Pointer (Interrupt
Acknowledge) Register
Transmit Channel 2 Completion Pointer (Interrupt
Acknowledge) Register
Transmit Channel 3 Completion Pointer (Interrupt
Acknowledge) Register
Transmit Channel 4 Completion Pointer (Interrupt
Acknowledge) Register
Transmit Channel 5 Completion Pointer (Interrupt
Acknowledge) Register
Transmit Channel 6 Completion Pointer (Interrupt
Acknowledge) Register
92
C6472/TCI6486 EMAC/MDIO
SPRUEF8F–March 2006–Revised November 2010
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EMAC Port Registers
Table 36. Ethernet Media Access Controller (EMAC) Registers (continued)
Offset
Acronym
Register Description
See
65Ch
TX7CP
Transmit Channel 7 Completion Pointer (Interrupt
Acknowledge) Register
660h
664h
668h
66Ch
670h
674h
678h
67Ch
RX0CP
RX1CP
RX2CP
RX3CP
RX4CP
RX5CP
RX6CP
RX7CP
Receive Channel 0 Completion Pointer (Interrupt
Acknowledge) Register
Receive Channel 1 Completion Pointer (Interrupt
Acknowledge) Register
Receive Channel 2 Completion Pointer (Interrupt
Acknowledge) Register
Receive Channel 3 Completion Pointer (Interrupt
Acknowledge) Register
Receive Channel 4 Completion Pointer (Interrupt
Acknowledge) Register
Receive Channel 5 Completion Pointer (Interrupt
Acknowledge) Register
Receive Channel 6 Completion Pointer (Interrupt
Acknowledge) Register
Receive Channel 7 Completion Pointer (Interrupt
Acknowledge) Register
Network Statistics Registers
200h
204h
208h
20Ch
210h
214h
218h
21Ch
220h
224h
228h
22Ch
230h
234h
238h
23Ch
240h
244h
248h
24Ch
250h
254h
258h
25Ch
260h
264h
268h
26Ch
270h
274h
278h
RXGOODFRAMES
RXBCASTFRAMES
RXMCASTFRAMES
RXPAUSEFRAMES
RXCRCERRORS
RXALIGNCODEERRORS
RXOVERSIZED
RXJABBER
Good Receive Frames
Total number of good broadcast frames received
Total number of good multicast frames received
Pause Receive Frames Register
Total number of frames received with CRC errors
Total number of frames received with alignment/code errors
Total number of oversized frames received
Total number of jabber frames received
Total number of undersized frames received
Receive Frame Fragments Register
RXUNDERSIZED
RXFRAGMENTS
RXFILTERED
Filtered Receive Frames
RXQOSFILTERED
RXOCTETS
Received Frames Filtered by QOS
Total number of received bytes in good frames
Total number of good frames transmitted
Broadcast Transmit Frames Register
TXGOODFRAMES
TXBCASTFRAMES
TXMCASTFRAMES
TXPAUSEFRAMES
TXDEFERRED
Multicast Transmit Frames Register
Pause Transmit Frames Register
Deferred Transmit Frames Register
TXCOLLISION
Transmit Collision Frames Register
TXSINGLECOLL
TXMULTICOLL
Transmit Single Collision Frames Register
Transmit Multiple Collision Frames Register
Transmit Excessive Collision Frames Register
Transmit Late Collision Frames Register
Transmit Underrun Error Register
TXEXCESSIVECOLL
TXLATECOLL
TXUNDERRUN
TXCARRIERSENSE
TXOCTETS
Transmit Carrier Sense Errors Register
Transmit Octet Frames Register
FRAME64
Transmit and Receive 64 Octet Frames Register
Transmit and Receive 65 to 127 Octet Frames Register
Transmit and Receive 128 to 255 Octet Frames Register
Transmit and Receive 256 to 511 Octet Frames Register
Transmit and Receive 512 to 1023 Octet Frames Register
FRAME65T127
FRAME128T255
FRAME256T511
FRAME512T1023
93
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Table 36. Ethernet Media Access Controller (EMAC) Registers (continued)
Offset
Acronym
Register Description
See
27Ch
FRAME1024TUP
Transmit and Receive 1024 to RXMAXLEN Octet Frames
Register
280h
284h
288h
28Ch
NETOCTETS
Network Octet Frames Register
RXSOFOVERRUNS
RXMOFOVERRUNS
RXDMAOVERRUNS
Receive FIFO or DMA Start-of-Frame Overruns Register
Receive FIFO or DMA Middle-of-Frame Overruns Register
Receive DMA Start-of-Frame and Middle-of-Frame Overruns
Register
94
C6472/TCI6486 EMAC/MDIO
SPRUEF8F–March 2006–Revised November 2010
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EMAC Port Registers
5.1 Transmit Identification and Version Register (TXIDVER)
Figure 43. Transmit Identification and Version Register (TXIDVER)
31
15
16
0
TXIDENT
0x000C
11
10
8
7
RTLVER
0x01
TXMAJORVER
0x02
TXMINORVER
0x08
LEGEND: R = Read only; -n = value after reset
Table 37. Transmit Identification and Version Register (TXIDVER) Field Descriptions
Bit
Field
Value Description
31-16 TXIDENT
15-11 RTLVER
Transmit identification value
RTL version value
10-8
7-0
TXMAJORVER
TXMINORVER
Transmit major version value
Transmit minor version value
95
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5.2 Transmit Control Register (TXCONTROL)
Figure 44. Transmit Control Register (TXCONTROL)
31
16
Reserved
R-0
15
1
0
Reserved
TXEN
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 38. Transmit Control Register (TXCONTROL) Field Descriptions
Bit
31-1
0
Field
Value Description
Reserved
TXEN
0
Reserved
Transmit enable
Transmit is disabled
Transmit is enabled
0
1
96
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EMAC Port Registers
5.3 Transmit Teardown Register (TXTEARDOWN)
Figure 45. Transmit Teardown Register (TXTEARDOWN)
31
30
16
0
TXTD
NRDY
Reserved
R-0
15
3
2
Reserved
R-0
TXTDNCH
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 39. Transmit Teardown Register (TXTEARDOWN) Field Descriptions
Bit
31
Field
Value Description
TXTDNRDY
Reserved
TXTDNCH
0
0
Transmit teardown ready. Read as zero, but is always assumed to be one (unused).
Reserved
30-3
2-0
Transmit teardown channel. The transmit teardown channel is commanded by writing the encoded
value of the transmit channel to be torn down. The teardown register is read as zero.
0
Teardown transmit channel 0
Teardown transmit channel 1
Teardown transmit channel 2
Teardown transmit channel 3
Teardown transmit channel 4
Teardown transmit channel 5
Teardown transmit channel 6
Teardown transmit channel 7
1h
2h
3h
4h
5h
6h
7h
97
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5.4 Receive Identification and Version Register (RXIDVER)
Figure 46. Receive Identification and Version Register (RXIDVER)
31
15
16
0
RXIDENT
0x000C
11
10
RXMAJORVER
0x02
8
7
RTLVER
0x01
RXMINORVER
0x08
LEGEND: R = Read only; -n = value after reset
Table 40. Receive Identification and Version Register (RXIDVER) Field Descriptions
Bit
Field
Value Description
31-16 RXIDENT
15-11 RTLVER
Receive identification value
RTL version value
10-8
7-0
RXMAJORVER
Receive major version value
Receive minor version value
RXMINORVER
98
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EMAC Port Registers
5.5 Receive Control Register (RXCONTROL)
Figure 47. Receive Control Register (RXCONTROL)
31
15
16
Reserved
R-0
1
0
Reserved
R-0
RXEN
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 41. Receive Control Register (RXCONTROL) Field Descriptions
Bit
31-1
0
Field
Value Description
Reserved
RXEN
0
Reserved
Receive DMA enable
Receive is disabled
Receive is enabled
0
1
99
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5.6 Receive Teardown Register (RXTEARDOWN)
Figure 48. Receive Teardown Register (RXTEARDOWN)
31
16
0
RXTD
NRDY
Reserved
R-0
15
3
2
Reserved
R-0
RXTDNCH
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 42. Receive Teardown Register (RXTEARDOWN) Field Descriptions
Bit
31
Field
Value Description
RXTDNRDY
Reserved
RXTDNCH
0
0
Receive teardown ready. Read as zero, but is always assumed to be one (unused).
Reserved
30-3
2-0
Receive teardown channel. Receive channel teardown is commanded by writing the encoded value
of the receive channel to be torn down. The teardown register is read as zero.
0
Teardown receive channel 0
Teardown receive channel 1
Teardown receive channel 2
Teardown receive channel 3
Teardown receive channel 4
Teardown receive channel 5
Teardown receive channel 6
Teardown receive channel 7
1h
2h
3h
4h
5h
6h
7h
100
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EMAC Port Registers
5.7 Transmit Interrupt Status (Unmasked) Register (TXINTSTATRAW)
The transmit interrupt status (unmasked) register (TXINTSTATRAW) is shown in Figure 49 and described
Figure 49. Transmit Interrupt Status (Unmasked) Register (TXINTSTATRAW)
31
15
16
Reserved
R-0
8
7
6
5
4
3
2
1
0
TX7
TX6
TX5
TX4
TX3
TX2
TX1
TX0
Reserved
R-0
PEND PEND PEND PEND PEND PEND PEND PEND
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
LEGEND: R = Read only; -n = value after reset
Table 43. Transmit Interrupt Status (Unmasked) Register (TXINTSTATRAW) Field Descriptions
Bit
31-8
7
Field
Value Description
Reserved
TX7PEND
TX6PEND
TX5PEND
TX4PEND
TX3PEND
TX2PEND
TX1PEND
TX0PEND
0
Reserved
TX7PEND raw interrupt read (before mask)
TX6PEND raw interrupt read (before mask)
TX5PEND raw interrupt read (before mask)
TX4PEND raw interrupt read (before mask)
TX3PEND raw interrupt read (before mask)
TX2PEND raw interrupt read (before mask)
TX1PEND raw interrupt read (before mask)
TX0PEND raw interrupt read (before mask)
6
5
4
3
2
1
0
101
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5.8 Transmit Interrupt Status (Masked) Register (TXINTSTATMASKED)
Figure 50. Transmit Interrupt Status (Masked) Register (TXINTSTATMASKED)
31
16
0
Reserved
R-0
15
8
7
6
5
4
3
2
1
TX7
TX6
TX5
TX4
TX3
TX2
TX1
TX0
Reserved
R-0
PEND PEND PEND PEND PEND PEND PEND PEND
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
LEGEND: R/W = R = Read only; -n = value after reset
Table 44. Transmit Interrupt Status (Masked) Register (TXINTSTATMASKED) Field Descriptions
Bit
31-8
7
Field
Value Description
Reserved
TX7PEND
TX6PEND
TX5PEND
TX4PEND
TX3PEND
TX2PEND
TX1PEND
TX0PEND
0
Reserved
TX7PEND masked interrupt read
TX6PEND masked interrupt read
TX5PEND masked interrupt read
TX4PEND masked interrupt read
TX3PEND masked interrupt read
TX2PEND masked interrupt read
TX1PEND masked interrupt read
TX0PEND masked interrupt read
6
5
4
3
2
1
0
102
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EMAC Port Registers
5.9 Transmit Interrupt Mask Set Register (TXINTMASKSET)
Figure 51. Transmit Interrupt Mask Set Register (TXINTMASKSET)
31
24
16
Reserved
R-0
23
22
21
20
19
18
17
TX7PULSE
MASK
TX6PULSE
MASK
TX5PULSE
MASK
TX4PULSE
MASK
TX3PULSE
MASK
TX2PULSE
MASK
TX1PULSE
MASK
TX0PULSE
MASK
15
8
Reserved
R-0
7
6
5
4
3
2
1
0
TX7PEND
MASK
TX6PEND
MASK
TX5PEND
MASK
TX4PEND
MASK
TX3PEND
MASK
TX2PEND
MASK
TX1PEND
MASK
TX0PEND
MASK
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 45. Transmit Interrupt Mask Set Register (TXINTMASKSET) Field Descriptions
Bit
Field
Value Description
31-24 Reserved
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Reserved; read as 0.
23
22
21
20
19
18
17
16
15-8
7
TX7PULSEMASK
Transmit channel 7 pulse interrupt mask. Write 1 to enable interrupt.
Transmit channel 6 pulse interrupt mask. Write 1 to enable interrupt.
Transmit channel 5 pulse interrupt mask. Write 1 to enable interrupt.
Transmit channel 4 pulse interrupt mask. Write 1 to enable interrupt.
Transmit channel 3 pulse interrupt mask. Write 1 to enable interrupt.
Transmit channel 2 pulse interrupt mask. Write 1 to enable interrupt.
Transmit channel 1 pulse interrupt mask. Write 1 to enable interrupt.
Transmit channel 0 pulse interrupt mask. Write 1 to enable interrupt.
Reserved; read as 0.
TX6PULSEMASK
TX5PULSEMASK
TX4PULSEMASK
TX3PULSEMASK
TX2PULSEMASK
TX1PULSEMASK
TX0PULSEMASK
Reserved
TX7PENDMASK
TX6PENDMASK
TX5PENDMASK
TX4PENDMASK
TX3PENDMASK
TX2PENDMASK
TX1PENDMASK
TX0PENDMASK
Transmit channel 7 pending interrupt mask. Write 1 to enable interrupt.
Transmit channel 6 pending interrupt mask. Write 1 to enable interrupt.
Transmit channel 5 pending interrupt mask. Write 1 to enable interrupt.
Transmit channel 4 pending interrupt mask. Write 1 to enable interrupt.
Transmit channel 3 pending interrupt mask. Write 1 to enable interrupt.
Transmit channel 2 pending interrupt mask. Write 1 to enable interrupt.
Transmit channel 1 pending interrupt mask. Write 1 to enable interrupt.
Transmit channel 0 pending interrupt mask. Write 1 to enable interrupt.
6
5
4
3
2
1
0
103
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5.10 Transmit Interrupt Mask Clear Register (TXINTMASKCLEAR)
Figure 52. Transmit Interrupt Mask Clear Register (TXINTMASKCLEAR)
31
24
Reserved
R-0
23
22
21
20
19
18
17
16
TX7PULSE
MASK
TX6PULSE
MASK
TX5PULSE
MASK
TX4PULSE
MASK
TX3PULSE
MASK
TX2PULSE
MASK
TX1PULSE
MASK
TX0PULSE
MASK
15
8
Reserved
R-0
7
6
5
4
3
2
1
0
TX7PEND
MASK
TX6PEND
MASK
TX5PEND
MASK
TX4PEND
MASK
TX3PEND
MASK
TX2PEND
MASK
TX1PEND
MASK
TX0PEND
MASK
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 46. Transmit Interrupt Mask Clear Register (TXINTMASKCLEAR) Field Descriptions
Bit
Field
Value Description
Reserved; read as 0.
31-24 Reserved
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
23
22
21
20
19
18
17
16
15-8
7
TX7PULSEMASK
Transmit channel 7 pulse interrupt mask. Write 1 to disable interrupt.
Transmit channel 6 pulse interrupt mask. Write 1 to disable interrupt.
Transmit channel 5 pulse interrupt mask. Write 1 to disable interrupt.
Transmit channel 4 pulse interrupt mask. Write 1 to disable interrupt.
Transmit channel 3 pulse interrupt mask. Write 1 to disable interrupt.
Transmit channel 2 pulse interrupt mask. Write 1 to disable interrupt.
Transmit channel 1 pulse interrupt mask. Write 1 to disable interrupt.
Transmit channel 0 pulse interrupt mask. Write 1 to disable interrupt.
Reserved; read as 0.
TX6PULSEMASK
TX5PULSEMASK
TX4PULSEMASK
TX3PULSEMASK
TX2PULSEMASK
TX1PULSEMASK
TX0PULSEMASK
Reserved
TX7PENDMASK
TX6PENDMASK
TX5PENDMASK
TX4PENDMASK
TX3PENDMASK
TX2PENDMASK
TX1PENDMASK
TX0PENDMASK
Transmit channel 7 pending interrupt mask. Write 1 to disable interrupt.
Transmit channel 6 pending interrupt mask. Write 1 to disable interrupt.
Transmit channel 5 pending interrupt mask. Write 1 to disable interrupt.
Transmit channel 4 pending interrupt mask. Write 1 to disable interrupt.
Transmit channel 3 pending interrupt mask. Write 1 to disable interrupt.
Transmit channel 2 pending interrupt mask. Write 1 to disable interrupt.
Transmit channel 1 pending interrupt mask. Write 1 to disable interrupt.
Transmit channel 0 pending interrupt mask. Write 1 to disable interrupt.
6
5
4
3
2
1
0
104
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EMAC Port Registers
5.11 MAC Input Vector Register (MACINVECTOR)
Figure 53. MAC Input Vector Register (MACINVECTOR)
31
30
29
18
17
16
USER LINK
HOST STAT
PEND PEND
Reserved
R-0
INT
R-0
INT
R-0
R-0
R-0
0
15
8
7
RXPEND
R-0
TXPEND
R-0
LEGEND: R = Read only; -n = value after reset
Table 47. MAC Input Vector Register (MACINVECTOR) Field Descriptions
Bit
31
30
Field
Value Description
USERINT
LINKINT
MDIO module user interrupt (USERINT) pending status bit
MDIO module link change interrupt (LINKINT) pending status bit
29-18 Reserved
0
Reserved
17
16
HOSTPEND
STATPEND
RXPEND
EMAC module host error interrupt (HOSTPEND) pending status bit
EMAC module statistics interrupt (STATPEND) pending status bit
15-8
7-0
Receive channels 0-7 interrupt (RXnPEND) pending status bit. Bit 8 is receive channel 0.
TXPEND
Transmit channels 0-7 interrupt (TXnPEND) pending status bit. Bit 0 is transmit channel 0.
105
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5.12 MAC End-of-Interrupt Vector Register (MACEOIVECTOR)
Figure 54. MAC End-of-Interrupt Vector Register (MACEOIVECTOR)
31
5
4
0
Reserved
R-0
MAC_EOI_VECTOR
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 48. MAC End-of-Interrupt Vector Register (MACEOIVECTOR) Field Descriptions
Bit
31-5
4
Field
Value Description
Reserved
0
Reserved
MAC_EOI_VECTOR
MAC end-of-interrupt vector
The EOI_VECTOR[4:0] pins reflect the value written to this location one peripheral bus clock
cycle after a write to this location. The EOI_WR signal is asserted for a single clock cycle after
a latency of two peripheral bus clock cycles when a write is performed to this location.
106
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EMAC Port Registers
5.13 Receive Interrupt Status (Unmasked) Register (RXINTSTATRAW)
Figure 55. Receive Interrupt Status (Unmasked) Register (RXINTSTATRAW)
31
15
16
Reserved
R-0
8
7
6
5
4
3
2
1
0
RX7
RX6
RX5
RX4
RX3
RX2
RX1
RX0
Reserved
R-0
PEND PEND PEND PEND PEND PEND PEND PEND
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
LEGEND: R = Read only; -n = value after reset
Table 49. Receive Interrupt Status (Unmasked) Register (RXINTSTATRAW) Field Descriptions
Bit
31-8
7
Field
Value Description
Reserved
RX7PEND
RX6PEND
RX5PEND
RX4PEND
RX3PEND
RX2PEND
RX1PEND
RX0PEND
0
Reserved
RX7PEND raw interrupt read (before mask)
RX6PEND raw interrupt read (before mask)
RX5PEND raw interrupt read (before mask)
RX4PEND raw interrupt read (before mask)
RX3PEND raw interrupt read (before mask)
RX2PEND raw interrupt read (before mask)
RX1PEND raw interrupt read (before mask)
RX0PEND raw interrupt read (before mask)
6
5
4
3
2
1
0
107
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5.14 Receive Interrupt Status (Masked) Register (RXINTSTATMASKED)
Figure 56. Receive Interrupt Status (Masked) Register (RXINTSTATMASKED)
31
16
0
Reserved
R-0
15
8
7
6
5
4
3
2
1
RX7
RX6
RX5
RX4
RX3
RX2
RX1
RX0
Reserved
R-0
PEND PEND PEND PEND PEND PEND PEND PEND
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
LEGEND: R = Read only; -n = value after reset
Table 50. Receive Interrupt Status (Masked) Register (RXINTSTATMASKED) Field Descriptions
Bit
31-8
7
Field
Value Description
Reserved
RX7PEND
RX6PEND
RX5PEND
RX4PEND
RX3PEND
RX2PEND
RX1PEND
RX0PEND
0
Reserved
RX7PEND masked interrupt read
RX6PEND masked interrupt read
RX5PEND masked interrupt read
RX4PEND masked interrupt read
RX3PEND masked interrupt read
RX2PEND masked interrupt read
RX1PEND masked interrupt read
RX0PEND masked interrupt read
6
5
4
3
2
1
0
108
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EMAC Port Registers
5.15 Receive Interrupt Mask Set Register (RXINTMASKSET)
Figure 57. Receive Interrupt Mask Set Register (RXINTMASKSET)
31
24
16
Reserved
R-0
23
22
21
20
19
18
17
RX7PULSE
MASK
RX6PULSE
MASK
RX5PULSE
MASK
RX4PULSE
MASK
RX3PULSE
MASK
RX2PULSE
MASK
RX1PULSE
MASK
RX0PULSE
MASK
15
8
Reserved
R-0
7
6
5
4
3
2
1
0
RX7PEND
MASK
RX6PEND
MASK
RX5PEND
MASK
RX4PEND
MASK
RX3PEND
MASK
RX2PEND
MASK
RX1PEND
MASK
RX0PEND
MASK
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 51. Receive Interrupt Mask Set Register (RXINTMASKSET) Field Descriptions
Bit
Field
Value Description
31-24 Reserved
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Reserved; read as 0.
23
22
21
20
19
18
17
16
15-8
7
RX7PULSEMASK
Receive channel 7 pulse interrupt mask. Write 1 to enable interrupt.
Receive channel 6 pulse interrupt mask. Write 1 to enable interrupt.
Receive channel 5 pulse interrupt mask. Write 1 to enable interrupt.
Receive channel 4 pulse interrupt mask. Write 1 to enable interrupt.
Receive channel 3 pulse interrupt mask. Write 1 to enable interrupt.
Receive channel 2 pulse interrupt mask. Write 1 to enable interrupt.
Receive channel 1 pulse interrupt mask. Write 1 to enable interrupt.
Receive channel 0 pulse interrupt mask. Write 1 to enable interrupt.
Reserved; read as 0.
RX6PULSEMASK
RX5PULSEMASK
RX4PULSEMASK
RX3PULSEMASK
RX2PULSEMASK
RX1PULSEMASK
RX0PULSEMASK
Reserved
RX7PENDMASK
RX6PENDMASK
RX5PENDMASK
RX4PENDMASK
RX3PENDMASK
RX2PENDMASK
RX1PENDMASK
RX0PENDMASK
Receive channel 7 pending interrupt mask. Write 1 to enable interrupt.
Receive channel 6 pending interrupt mask. Write 1 to enable interrupt.
Receive channel 5 pending interrupt mask. Write 1 to enable interrupt.
Receive channel 4 pending interrupt mask. Write 1 to enable interrupt.
Receive channel 3 pending interrupt mask. Write 1 to enable interrupt.
Receive channel 2 pending interrupt mask. Write 1 to enable interrupt.
Receive channel 1 pending interrupt mask. Write 1 to enable interrupt.
Receive channel 0 pending interrupt mask. Write 1 to enable interrupt.
6
5
4
3
2
1
0
109
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5.16 Receive Interrupt Mask Clear Register (RXINTMASKCLEAR)
Figure 58. Receive Interrupt Mask Clear Register (RXINTMASKCLEAR)
31
24
Reserved
R-0
23
22
21
20
19
18
17
16
RX7PULSE
MASK
RX6PULSE
MASK
RX5PULSE
MASK
RX4PULSE
MASK
RX3PULSE
MASK
RX2PULSE
MASK
RX1PULSE
MASK
RX0PULSE
MASK
15
8
Reserved
R-0
7
6
5
4
3
2
1
0
RX7PEND
MASK
RX6PEND
MASK
RX5PEND
MASK
RX4PEND
MASK
RX3PEND
MASK
RX2PEND
MASK
RX1PEND
MASK
RX0PEND
MASK
LEGEND: R = Read only; R/W = Read/Write; R/WC = Read/Write 1 to clear; -n = value after reset
Table 52. Receive Interrupt Mask Clear Register (RXINTMASKCLEAR) Field Descriptions
Bit
Field
Value Description
31-24 Reserved
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Reserved; read as 0.
23
22
21
20
19
18
17
16
15-8
7
RX7PULSEMASK
Receive channel 7 pulse interrupt mask. Write 1 to disable interrupt.
Receive channel 6 pulse interrupt mask. Write 1 to disable interrupt.
Receive channel 5 pulse interrupt mask. Write 1 to disable interrupt.
Receive channel 4 pulse interrupt mask. Write 1 to disable interrupt.
Receive channel 3 pulse interrupt mask. Write 1 to disable interrupt.
Receive channel 2 pulse interrupt mask. Write 1 to disable interrupt.
Receive channel 1 pulse interrupt mask. Write 1 to disable interrupt.
Receive channel 0 pulse interrupt mask. Write 1 to disable interrupt.
Reserved; read as 0.
RX6PULSEMASK
RX5PULSEMASK
RX4PULSEMASK
RX3PULSEMASK
RX2PULSEMASK
RX1PULSEMASK
RX0PULSEMASK
Reserved
RX7PENDMASK
RX6PENDMASK
RX5PENDMASK
RX4PENDMASK
RX3PENDMASK
RX2PENDMASK
RX1PENDMASK
RX0PENDMASK
Receive channel 7 pending interrupt mask. Write 1 to disable interrupt.
Receive channel 6 pending interrupt mask. Write 1 to disable interrupt.
Receive channel 5 pending interrupt mask. Write 1 to disable interrupt.
Receive channel 4 pending interrupt mask. Write 1 to disable interrupt.
Receive channel 3 pending interrupt mask. Write 1 to disable interrupt.
Receive channel 2 pending interrupt mask. Write 1 to disable interrupt.
Receive channel 1 pending interrupt mask. Write 1 to disable interrupt.
Receive channel 0 pending interrupt mask. Write 1 to disable interrupt.
6
5
4
3
2
1
0
110
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EMAC Port Registers
5.17 MAC Interrupt Status (Unmasked) Register (MACINTSTATRAW)
Figure 59. MAC Interrupt Status (Unmasked) Register (MACINTSTATRAW)
31
15
16
Reserved
R-0
2
1
0
HOST STAT
PEND PEND
Reserved
R-0
R-0
R-0
LEGEND: R = Read only; -n = value after reset
Table 53. MAC Interrupt Status (Unmasked) Register (MACINTSTATRAW) Field Descriptions
Bit
31-2
1
Field
Value Description
Reserved
0
Reserved
HOSTPEND
STATPEND
Host pending interrupt (HOSTPEND); raw interrupt read (before mask)
Statistics pending interrupt (STATPEND); raw interrupt read (before mask)
0
111
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5.18 MAC Interrupt Status (Masked) Register (MACINTSTATMASKED)
Figure 60. MAC Interrupt Status (Masked) Register (MACINTSTATMASKED)
31
15
16
Reserved
R-0
2
1
0
HOST STAT
PEND PEND
Reserved
R-0
R-0
R-0
LEGEND: R/W = R = Read only; -n = value after reset
Table 54. MAC Interrupt Status (Masked) Register (MACINTSTATMASKED) Field Descriptions
Bit
31-2
1
Field
Value Description
Reserved
0
Reserved
HOSTPEND
STATPEND
Host pending interrupt (HOSTPEND); masked interrupt read
Statistics pending interrupt (STATPEND); masked interrupt read
0
112
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EMAC Port Registers
5.19 MAC Interrupt Mask Set Register (MACINTMASKSET)
Figure 61. MAC Interrupt Mask Set Register (MACINTMASKSET)
31
15
16
Reserved
R-0
2
1
0
HOST
MASK
STAT
MASK
Reserved
R-0
R/WS-0
R/WS-0
LEGEND: R = Read only; R/W = Read/Write; R/WS = Read/Write 1 to set; -n = value after reset
Table 55. MAC Interrupt Mask Set Register (MACINTMASKSET) Field Descriptions
Bit
31-2
1
Field
Value Description
Reserved
HOSTMASK
STATMASK
0
Reserved
Host error interrupt mask set bit. Write 1 to enable interrupt, a write of 0 has no effect.
Statistics interrupt mask set bit. Write 1 to enable interrupt, a write of 0 has no effect.
0
113
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5.20 MAC Interrupt Mask Clear Register (MACINTMASKCLEAR)
Figure 62. MAC Interrupt Mask Clear Register (MACINTMASKCLEAR)
31
15
16
Reserved
R-0
2
1
0
HOST
MASK
STAT
MASK
Reserved
R-0
R/WC-0
R/WC-0
LEGEND: R = Read only; R/W = Read/Write; R/WC = Read/Write 1 to clear; -n = value after reset
Table 56. MAC Interrupt Mask Clear Register (MACINTMASKCLEAR) Field Descriptions
Bit
31-2
1
Field
Value Description
Reserved
0
Reserved
HOSTMASK
STATMASK
Host error interrupt mask clear bit. Write 1 to disable interrupt, a write of 0 has no effect.
Statistics interrupt mask clear bit. Write 1 to disable interrupt, a write of 0 has no effect.
0
114
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EMAC Port Registers
5.21 Receive Multicast/Broadcast/Promiscuous Channel Enable Register
(RXMBPENABLE)
The receive multicast/broadcast/promiscuous channel enable register (RXMBPENABLE) is shown in
Figure 63. Receive Multicast/Broadcast/Promiscuous Channel Enable Register (RXMBPENABLE)
31
Reserved
R-0
30
29
28
27
19
11
3
25
24
RXPASSCRC
R/W-0
RXQOSEN
R/W-0
RXNOCHAIN
R/W-0
Reserved
R-0
RXCMFEN
R/W-0
23
22
21
20
18
10
2
16
8
RXCSFEN
R/W-0
RXCEFEN
R/W-0
RXCAFEN
R/W-0
Reserved
RXPROMCH
R/W-0
R-0
15
14
13
12
Reserved
RXBROADEN
R/W-0
Reserved
R-0
RXBROADCH
R/W-0
R-0
7
6
5
4
0
Reserved
R-0
RXMULTEN
R/W-0
Reserved
R-0
RXMULTCH
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 57. Receive Multicast/Broadcast/Promiscuous Channel Enable Register (RXMBPENABLE)
Field Descriptions
Bit
31
30
Field
Value Description
Reserved
RXPASSCRC
0
Reserved
Pass receive CRC enable bit
0
1
Received CRC is discarded for all channels and is not included in the buffer descriptor packet
length field
Received CRC is transferred to memory for all channels and is included in the buffer descriptor
packet length
29
28
RXQOSEN
Receive quality of service enable bit
Receive QOS is disabled
0
1
Receive QOS is enabled
RXNOCHAIN
Receive no buffer chaining bit
Received frames can span multiple buffers
0
1
Receive DMA controller transfers each frame into a single buffer regardless of the frame or buffer
size. All remaining frame data after the first buffer is discarded. The buffer descriptor buffer length
field will contain the entire frame byte count (up to 65535 bytes).
27-25 Reserved
0
Reserved
24
RXCMFEN
Receive copy MAC control frames enable bit. Enables MAC control frames to be transferred to
memory. MAC control frames are normally acted upon (if enabled), but not copied to memory. MAC
control frames that are pause frames will be acted upon if enabled in MACCONTROL, regardless of
the value of RXCMFEN. Frames transferred to memory due to RXCMFEN will have the CONTROL
bit set in their EOP buffer descriptor.
0
1
MAC control frames are filtered (but acted upon if enabled)
MAC control frames are transferred to memory
23
RXCSFEN
Receive copy short frames enable bit. Enables frames or fragments shorter than 64 bytes to be
copied to memory. Frames transferred to memory due to RXCSFEN will have the FRAGMENT or
UNDERSIZE bit set in their EOP buffer descriptor. Fragments are short frames that contain
CRC/align/code errors and undersized are short frames without errors.
0
1
Short frames are filtered
Short frames are transferred to memory
115
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Table 57. Receive Multicast/Broadcast/Promiscuous Channel Enable Register (RXMBPENABLE) Field
Descriptions (continued)
Bit
Field
Value Description
22
RXCEFEN
Receive copy error frames enable bit. Enables frames containing errors to be transferred to
memory. The appropriate error bit will be set in the frame EOP buffer descriptor.
Frames containing errors are filtered
0
1
Frames containing errors are transferred to memory
21
RXCAFEN
Receive copy all frames enable bit. Enables frames that do not address match (includes multicast
frames that do not hash match) to be transferred to the promiscuous channel selected by
RXPROMCH bits. Such frames will be marked with the NOMATCH bit in their EOP buffer
descriptor.
0
1
Frames that do not address match are filtered
Frames that do not address match are transferred to the promiscuous channel selected by
RXPROMCH bits
20-19 Reserved
0
0-3h
0
Reserved
18-16 RXPROMCH
Receive promiscuous channel select
Select channel 0 to receive promiscuous frames
Select channel 1 to receive promiscuous frames
Select channel 2 to receive promiscuous frames
Select channel 3 to receive promiscuous frames
Select channel 4 to receive promiscuous frames
Select channel 5 to receive promiscuous frames
Select channel 6 to receive promiscuous frames
Select channel 7 to receive promiscuous frames
Reserved
1h
2h
3h
4h
5h
6h
7h
0
15-14 Reserved
13
RXBROADEN
Receive broadcast enable. Enable received broadcast frames to be copied to the channel selected
by RXBROADCH bits.
0
1
Broadcast frames are filtered
Broadcast frames are copied to the channel selected by RXBROADCH bits
Reserved
12-11 Reserved
0
10-8
RXBROADCH
0-3h
0
Receive broadcast channel select
Select channel 0 to receive broadcast frames
Select channel 1 to receive broadcast frames
Select channel 2 to receive broadcast frames
Select channel 3 to receive broadcast frames
Select channel 4 to receive broadcast frames
Select channel 5 to receive broadcast frames
Select channel 6 to receive broadcast frames
Select channel 7 to receive broadcast frames
Reserved
1h
2h
3h
4h
5h
6h
7h
0
7-6
5
Reserved
RXMULTEN
RX multicast enable. Enable received hash matching multicast frames to be copied to the channel
selected by RXMULTCH bits.
0
1
0
Multicast frames are filtered
Multicast frames are copied to the channel selected by RXMULTCH bits
Reserved
4-3
Reserved
116
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EMAC Port Registers
Table 57. Receive Multicast/Broadcast/Promiscuous Channel Enable Register (RXMBPENABLE) Field
Descriptions (continued)
Bit
Field
Value Description
2-0
RXMULTCH
0-3h
0
Receive multicast channel select
Select channel 0 to receive multicast frames
Select channel 1 to receive multicast frames
Select channel 2 to receive multicast frames
Select channel 3 to receive multicast frames
Select channel 4 to receive multicast frames
Select channel 5 to receive multicast frames
Select channel 6 to receive multicast frames
Select channel 7 to receive multicast frames
1h
2h
3h
4h
5h
6h
7h
117
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5.22 Receive Unicast Enable Set Register (RXUNICASTSET)
Figure 64. Receive Unicast Enable Set Register (RXUNICASTSET)
31
16
Reserved
R-0
15
8
7
6
5
4
3
2
1
0
Reserved
R-0
RXCH7EN RXCH6EN RXCH5EN RXCH4EN RXCH3EN RXCH2EN RXCH1EN RXCH0EN
R/WS-0 R/WS-0 R/WS-0 R/WS-0 R/WS-0 R/WS-0 R/WS-0 R/WS-0
LEGEND: R = Read only; R/W = Read/Write; R/WS = Read/Write 1 to set; -n = value after reset
Table 58. Receive Unicast Enable Set Register (RXUNICASTSET) Field Descriptions
Bit
31-8
7
Field
Value Description
Reserved
0
Reserved
RXCH7EN
Receive channel 7 unicast enable set bit. Write 1 to set the enable, a write of 0 has no effect. May
be read.
6
5
4
3
2
1
0
RXCH6EN
RXCH5EN
RXCH4EN
RXCH3EN
RXCH2EN
RXCH1EN
RXCH0EN
Receive channel 6 unicast enable set bit. Write 1 to set the enable, a write of 0 has no effect. May
be read.
Receive channel 5 unicast enable set bit. Write 1 to set the enable, a write of 0 has no effect. May
be read.
Receive channel 4 unicast enable set bit. Write 1 to set the enable, a write of 0 has no effect. May
be read.
Receive channel 3 unicast enable set bit. Write 1 to set the enable, a write of 0 has no effect. May
be read.
Receive channel 2 unicast enable set bit. Write 1 to set the enable, a write of 0 has no effect. May
be read.
Receive channel 1 unicast enable set bit. Write 1 to set the enable, a write of 0 has no effect. May
be read.
Receive channel 0 unicast enable set bit. Write 1 to set the enable, a write of 0 has no effect. May
be read.
118
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EMAC Port Registers
5.23 Receive Unicast Clear Register (RXUNICASTCLEAR)
The receive unicast clear register (RXUNICASTCLEAR) is shown in Figure 65 and described in Table 59.
Figure 65. Receive Unicast Clear Register (RXUNICASTCLEAR)
31
16
Reserved
R-0
15
8
7
6
5
4
3
2
1
0
Reserved
R-0
RXCH7EN RXCH6EN RXCH5EN RXCH4EN RXCH3EN RXCH2EN RXCH1EN RXCH0EN
R/WC-0 R/WC-0 R/WC-0 R/WC-0 R/WC-0 R/WC-0 R/WC-0 R/WC-0
LEGEND: R = Read only; R/W = Read/Write; R/WC = Read/Write 1 to clear; -n = value after reset
Table 59. Receive Unicast Clear Register (RXUNICASTCLEAR) Field Descriptions
Bit
31-8
7
Field
Value Description
Reserved
RXCH7EN
RXCH6EN
RXCH5EN
RXCH4EN
RXCH3EN
RXCH2EN
RXCH1EN
RXCH0EN
0
Reserved
Receive channel 7 unicast enable clear bit. Write 1 to clear the enable, a write of 0 has no effect.
Receive channel 6 unicast enable clear bit. Write 1 to clear the enable, a write of 0 has no effect.
Receive channel 5 unicast enable clear bit. Write 1 to clear the enable, a write of 0 has no effect.
Receive channel 4 unicast enable clear bit. Write 1 to clear the enable, a write of 0 has no effect.
Receive channel 3 unicast enable clear bit. Write 1 to clear the enable, a write of 0 has no effect.
Receive channel 2 unicast enable clear bit. Write 1 to clear the enable, a write of 0 has no effect.
Receive channel 1 unicast enable clear bit. Write 1 to clear the enable, a write of 0 has no effect.
Receive channel 0 unicast enable clear bit. Write 1 to clear the enable, a write of 0 has no effect.
6
5
4
3
2
1
0
119
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5.24 Receive Maximum Length Register (RXMAXLEN)
Figure 66. Receive Maximum Length Register (RXMAXLEN)
31
15
16
0
Reserved
R-0
RXMAXLEN
R/W-1518
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 60. Receive Maximum Length Register (RXMAXLEN) Field Descriptions
Bit
31-16 Reserved
15-0 RXMAXLEN
Field
Value Description
Reserved
0
Receive maximum frame length. These bits determine the maximum length of a received frame.
The reset value is 5EEh (1518). Frames with byte counts greater than RXMAXLEN are long
frames. Long frames with no errors are oversized frames. Long frames with CRC, code, or
alignment errors are jabber frames.
120
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EMAC Port Registers
5.25 Receive Buffer Offset Register (RXBUFFEROFFSET)
The receive buffer offset register (RXBUFFEROFFSET) is shown in Figure 67 and described in Table 61.
Figure 67. Receive Buffer Offset Register (RXBUFFEROFFSET)
31
15
16
Reserved
R-0
0
RXBUFFEROFFSET
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 61. Receive Buffer Offset Register (RXBUFFEROFFSET) Field Descriptions
Bit
31-16 Reserved
15-0 RXBUFFEROFFSET
Field
Value Description
Reserved
0
Receive buffer offset value. These bits are written by the EMAC into each frame SOP
buffer descriptor Buffer Offset field. The frame data begins after the RXBUFFEROFFSET
value of bytes. A value of 0 indicates that there are no unused bytes at the beginning of
the data and that valid data begins on the first byte of the buffer. A value of Fh (15)
indicates that the first 15 bytes of the buffer are to be ignored by the EMAC and that valid
buffer data starts on byte 16 of the buffer. This value is used for all channels.
121
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5.26 Receive Filter Low Priority Frame Threshold Register (RXFILTERLOWTHRESH)
The receive filter low priority frame threshold register (RXFILTERLOWTHRESH) is shown in Figure 68
Figure 68. Receive Filter Low Priority Frame Threshold Register (RXFILTERLOWTHRESH)
31
15
16
Reserved
R-0
8
7
0
Reserved
R-0
RXFILTERTHRESH
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 62. Receive Filter Low Priority Frame Threshold Register (RXFILTERLOWTHRESH) Field
Descriptions
Bit
31-8
7-0
Field
Value Description
Reserved
0
Reserved
RXFILTERTHRESH
Receive filter low threshold. These bits contain the free buffer count threshold value for
filtering low priority incoming frames. This field should remain 0 if no filtering is desired.
122
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EMAC Port Registers
5.27 Receive Channel 0-7 Flow Control Threshold Register (RXnFLOWTHRESH)
Figure 69. Receive Channel n Flow Control Threshold Register (RXnFLOWTHRESH)
31
15
16
Reserved
R-0
8
7
0
Reserved
R-0
RXnFLOWTHRESH
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 63. Receive Channel n Flow Control Threshold Register (RXnFLOWTHRESH) Field
Descriptions
Bit
31-8
7-0
Field
Value Description
Reserved
0
Reserved
RXnFLOWTHRESH
Receive flow threshold. These bits contain the threshold value for issuing flow control on
incoming frames for channel n (when enabled).
123
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5.28 Receive Channel 0-7 Free Buffer Count Register (RXnFREEBUFFER)
Figure 70. Receive Channel n Free Buffer Count Register (RXnFREEBUFFER)
31
15
16
0
Reserved
R-0
RXnFREEBUF
WI-0
tLEGEND: R = Read only; R/W = Read/Write; WI = Write to increment; -n = value after reset
Table 64. Receive Channel n Free Buffer Count Register (RXnFREEBUFFER) Field Descriptions
Bit
31-16 Reserved
15-0 RXnFREEBUF
Field
Value Description
0
Reserved
Receive free buffer count. These bits contain the count of free buffers available. The
RXFILTERTHRESH value is compared with this field to determine if low priority frames should be
filtered. The RXnFLOWTHRESH value is compared with this field to determine if receive flow
control should be issued against incoming packets (if enabled). This is a write-to-increment field.
This field rolls over to zero on overflow. If hardware flow control or QOS is used, the host must
initialize this field to the number of available buffers (one register per channel). The EMAC
decrements (by the number of buffers in the received frame) the associated channel register for
each received frame. The host must write this field with the number of buffers that have been freed
due to host processing.
124
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EMAC Port Registers
5.29 MAC Control Register (MACCONTROL)
Figure 71. MAC Control Register (MACCONTROL)
31
23
15
24
Reserved
R-0
19
18
17
16
Reserved
R-0
RGMIIEN
GIGFORCE
RMIIDUPLEXMODE
R/W-0
R/W-0
R/W-0
14
13
12
11
10
9
8
RXFIFO
FLOWEN
RMIISPEED RXOFFLENBLOCK RXOWNERSHIP
CMDIDLE
Reserved
TXPTYPE
Reserved
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R-0
R/W-0
R-0
7
6
5
4
3
2
1
0
GIG
TXPACE
R/W-0
GMIIEN
R/W-0
TXFLOWEN
R/W-0
RXBUFFERFLOWEN
R/W-0
Reserved
R-0
LOOPBACK
R/W-0
FULLDUPLEX
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 65. MAC Control Register (MACCONTROL) Field Descriptions
Bit
Field
Value Description
31-19 Reserved
0
Reserved
18
RGMIIEN
RGMII enable bit. Enables the fullduplex and gigabit mode to be selected from the
RGMIIFULLDUPLEX and RGMIIGIG input signals and not from the FULLDUPLEX and GIG
bits contained in this register. This bit is directly connected to the RXINBAND input on the
RGMII module.
0
1
The RGMII interface is in forced link mode. The duplexity is determined by the FULLDUPLEX
bit, and the speed is determined by the GIG bit. The speed is either 1 Gbps or 100 Mbps; 10
Mbps is not supported in forced link mode.
The RGMII interface requires and uses the in-band signals coming in on its receive.
17
16
GIGFORCE
Gigabit force mode. This bit is used to force the EMAC into gigabit mode if the input MTCLK
signal has been stopped by the PHY.
RMIIDUPLEXMODE
Duplex mode for the RMII interface.
0
1
The RMII operates in half-duplex mode. This mode is not supported in the TCI6486/C6472
devices.
The RMII operates in full-duplex mode.
15
14
RMIISPEED
Operating speed for the RMII interface
0
1
The RMII operates at 2.5 MHz (10Mbps mode)
The RMII operates at 25 MHz (100 Mbps mode)
Receive offset / length word write block
RXOFFLENBLOCK
0
1
Do not block the DMA writes to the receive buffer descriptor offset/buffer length word
Block all EMAC DMA controller writes to the receive buffer descriptor offset/buffer length
words during packet processing. When this bit is set, the EMAC will never write the third word
to any receive buffer descriptor.
13
RXOWNERSHIP
Receive ownership write bit value
0
1
The EMAC writes the Receive ownership bit to zero at the end-of-packet processing
The EMAC writes the Receive ownership bit to one at the end-of-packet processing. If you do
not use the ownership mechanism, you can set this mode to preclude the necessity of
software having to set this bit each time the buffer descriptor is used.
125
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Table 65. MAC Control Register (MACCONTROL) Field Descriptions (continued)
Bit
Field
Value Description
Receive FIFO flow control enable
Receive flow control disabled. For full-duplex mode, no outgoing pause frames are sent.
12
RXFIFOFLOWEN
0
1
Receive flow control enabled. For full-duplex mode, outgoing pause frames are sent when
receive FIFO flow control is triggered.
11
CMDIDLE
Command Idle bit
0
1
0
Idle not commanded
Idle commanded (read IDLE in the MACSTATUS register)
Reserved
10
9
Reserved
TXPTYPE
Transmit queue priority type
0
1
The queue uses a round-robin scheme to select the next channel for transmission
The queue uses a fixed-priority (channel 7 highest priority) scheme to select the next channel
for transmission
8
7
Reserved
GIG
0
Reserved
Gigabit mode
0
1
Gigabit mode is disabled; 10/100 mode is in operation
Gigabit mode is enabled (full-duplex only)
Transmit pacing enable bit
6
5
4
TXPACE
GMIIEN
0
1
Transmit pacing is disabled
Transmit pacing is enabled
GMII enable bit
0
1
GMII RX and TX are held in reset
GMII RX and TX are enabled for receive and transmit
TXFLOWEN
Transmit flow control enable bit. This bit determines if incoming pause frames are acted upon
in full-duplex mode. Incoming pause frames are not acted upon in half-duplex mode,
regardless of this bit setting. The RXMBPENABLE bits determine whether or not received
pause frames are transferred to memory.
0
1
Transmit flow control is disabled. Full-duplex mode: incoming pause frames are not acted
upon.
Transmit flow control is enabled. Full-duplex mode: incoming pause frames are acted upon.
Receive buffer flow control enable bit
3
RXBUFFERFLOWEN
0
1
Receive flow control is disabled. Half-duplex mode: no flow control generated collisions are
sent. Full-duplex mode: no outgoing pause frames are sent.
Receive flow control is enabled. Half-duplex mode: collisions are initiated when receive buffer
flow control is triggered. Full-duplex mode: outgoing pause frames are sent when receive flow
control is triggered.
2
1
Reserved
0
Reserved
LOOPBACK
Loopback mode. The loopback mode forces internal full-duplex mode regardless of the
FULLDUPLEX bit. The loopback bit should be changed only when the GMIIEN bit is
de-asserted.
0
1
Loopback mode is disabled
Loopback mode is enabled
0
FULLDUPLEX
Full duplex mode. The gigabit mode forces full duplex mode regardless of whether the
FULLDUPLEX bit is set or not.
0
1
Half-duplex mode is enabled
Full-duplex mode is enabled
126
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EMAC Port Registers
5.30 MAC Status Register (MACSTATUS)
Figure 72. MAC Status Register (MACSTATUS)
31
30
24
16
8
IDLE
Reserved
R-0
R-0
23
20
19
18
TXERRCODE
Reserved
R-0
TXERRCH
R-0
R-0
15
7
12
11
10
RXERRCODE
R-0
Reserved
RXERRCH
R-0
R-0
5
4
3
2
1
0
Reserved
RDMIIGIG
RGMIIFULLDUPLEX
RXQOSACT
RXFLOWACT
TXFLOWACT
R-0
R-x
R-x
R-0
R-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 66. MAC Status Register (MACSTATUS) Field Descriptions
Bit
Field
Value Description
31
IDLE
EMAC idle bit. This bit is set to 0 at reset; one clock after reset it goes to 1.
0
1
0
The EMAC is not idle
The EMAC is in the idle state
Reserved
30-24 Reserved
23-20 TXERRCODE
Transmit host error code. These bits indicate that EMAC detected transmit DMA related host
errors. The host should read this field after a host error interrupt (HOSTPEND) to determine
the error. Host error interrupts require a hardware reset in order to recover. A zero packet
length is an error, but it is not detected.
0
1h
2h
3h
4h
5h
6h
0
No error
SOP error; the buffer is the first buffer in a packet, but the SOP bit is not set in software.
Ownership bit not set in SOP buffer
Zero next buffer descriptor pointer without EOP
Zero buffer pointer
Zero buffer length
Packet length error (sum of buffers < packet length)
Reserved
19
Reserved
18-16 TXERRCH
0-3h
Transmit host error channel. These bits indicate on which transmit channel the host error
occurred. This field is cleared to 0 on a host read.
0
The host error occurred on transmit channel 0.
The host error occurred on transmit channel 1.
The host error occurred on transmit channel 2.
The host error occurred on transmit channel 3.
The host error occurred on transmit channel 4.
The host error occurred on transmit channel 5.
The host error occurred on transmit channel 6.
The host error occurred on transmit channel 7.
1h
2h
3h
4h
5h
6h
7h
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Table 66. MAC Status Register (MACSTATUS) Field Descriptions (continued)
Bit
Field
Value Description
15-12 RXERRCODE
Receive host error code. These bits indicate that EMAC detected receive DMA related host
errors. The host should read this field after a host error interrupt (HOSTPEND) to determine
the error. Host error interrupts require a hardware reset in order to recover.
0
2h
4h
0
No error
Ownership bit not set in SOP buffer.
Zero buffer pointer
Reserved
11
Reserved
10-8
RXERRCH
0-3h
Receive host error channel. These bits indicate on which receive channel the host error
occurred. This field is cleared to 0 on a host read.
0
The host error occurred on receive channel 0.
The host error occurred on receive channel 1.
The host error occurred on receive channel 2.
The host error occurred on receive channel 3.
The host error occurred on receive channel 4.
The host error occurred on receive channel 5.
The host error occurred on receive channel 6.
The host error occurred on receive channel 7.
Reserved
1h
2h
3h
4h
5h
6h
7h
0
7-5
4
Reserved
RGMIIGIG
RGMII gigabit. This is the value of RGMIIGIG input.
RGMII full-duplex. This is the value of RGMIIFULLDUPLEX input.
3
RGMIIFULLDUPLEX
RXQOSACT
2
Receive Quality of Service (QOS) active bit. When asserted, indicates that receive quality of
service is enabled and that at least one channel freebuffer count (RXnFREEBUFFER) is less
than or equal to the RXFILTERLOWTHRESH value.
0
1
Receive quality of service is disabled.
Receive quality of service is enabled.
1
0
RXFLOWACT
TXFLOWACT
Receive flow control active bit. When asserted, indicates that at least one channel freebuffer
count (RXnFREEBUFFER) is less than or equal to the channel's corresponding
RXnFILTERTHRESH value.
0
1
Receive flow control is inactive
Receive flow control is active
Transmit flow control active bit. When asserted, this bit indicates that the pause time period is
being observed for a received pause frame. No new transmissions will begin while this bit is
asserted except for the transmission of pause frames. Any transmission in progress when this
bit is asserted will complete.
0
1
Transmit flow control is inactive
Transmit flow control is active
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EMAC Port Registers
5.31 Emulation Control Register (EMCONTROL)
Figure 73. Emulation Control Register (EMCONTROL)
31
15
16
Reserved
R-0
2
1
0
Reserved
R-0
SOFT FREE
R/W-0 R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 67. Emulation Control Register (EMCONTROL) Field Descriptions
Bit
31-2
1
Field
Value Description
Reserved
SOFT
0
Reserved
Emulation soft bit
Emulation free bit
0
FREE
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5.32 FIFO Control Register (FIFOCONTROL)
Figure 74. FIFO Control Register (FIFOCONTROL)
31
15
23
22
16
0
Reserved
R-0
RXFIFOFLOWTHRESH
R/W-2
5
4
Reserved
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
TXCELLTHRESH
R/W-24
Table 68. FIFO Control Register (FIFOCONTROL) Field Descriptions
Bit
Field
Value Description
31-23 Reserved
0
Reserved
22-16 RXFIFOFLOWTHRESH
Receive FIFO flow control threshold. Occupancy of the receive FIFO when Receive FIFO
flow control is triggered (if enabled). The default value is 0x2, which means that receive
FIFO flow control is triggered when the occupancy of the FIFO reaches two cells.
15-5
4-0
Reserved
0
Reserved
TXCELLTHRESH
Transmit FIFO cell threshold. Indicates the number of 64-byte packet cells required to be
in the transmit FIFO before the packet transfer is initiated. Packets with fewer cells are
initiated when the complete packet is contained in the FIFO. This value must be greater
then or equal to 2 and less than or equal to 24.
130
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EMAC Port Registers
5.33 MAC Configuration Register (MACCONFIG)
Figure 75. MAC Configuration Register (MACCONFIG)
31
15
24
23
16
0
TXCELLDEPTH
R-24
RXCELLDEPTH
R-68
8
7
ADDRESSTYPE
R-2
MACCFIG
R-3
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 69. MAC Configuration Register (MACCONFIG) Field Descriptions
Bit
Field
Value Description
31-24 TXCELLDEPTH
23-16 RXCELLDEPTH
Transmit cell depth. These bits indicate the number of cells in the transmit FIFO.
Receive cell depth. These bits indicate the number of cells in the receive FIFO.
Address type
15-8
7-0
ADDRESSTYPE
MACCFIG
MAC configuration value
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5.34 Soft Reset Register (SOFTRESET)
Figure 76. Soft Reset Register (SOFTRESET)
31
16
Reserved
R-0
15
1
0
Reserved
SOFTRESET
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 70. Soft Reset Register (SOFTRESET) Field Descriptions
Bit
31-1
0
Field
Value Description
Reserved
SOFTRESET
0
Reserved
Software reset. Writing a one to this bit causes the EMAC logic to be reset. Software reset occurs
when the receive and transmit DMA controllers are in an idle state to avoid locking up the
Configuration bus. After writing a one to this bit, it may be polled to determine if the reset has
occurred. If a one is read, the reset has not yet occurred. If a zero is read, then reset has occurred.
0
1
A software reset has not occurred
A software reset has occurred
132
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EMAC Port Registers
5.35 MAC Source Address Low Bytes Register (MACSRCADDRLO)
Figure 77. MAC Source Address Low Bytes Register (MACSRCADDRLO)
31
15
16
Reserved
R-0
8
7
0
MACSRCADDR0
R/W-0
MACSRCADDR1
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 71. MAC Source Address Low Bytes Register (MACSRCADDRLO) Field Descriptions
Bit
Field
Value Description
31-16 Reserved
0
Reserved
15-8
7-0
MACSRCADDR0
MACSRCADDR1
MAC source address lower 8 bits (byte 0)
MAC source address bits 15-8 (byte 1)
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5.36 MAC Source Address High Bytes Register (MACSRCADDRHI)
Figure 78. MAC Source Address High Bytes Register (MACSRCADDRHI)
31
15
24
23
16
0
MACSRCADDR2
R/W-0
MACSRCADDR3
R/W-0
8
7
MACSRCADDR4
R/W-0
MACSRCADDR5
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 72. MAC Source Address High Bytes Register (MACSRCADDRHI) Field Descriptions
Bit
Field
Value Description
MAC source address bits 23-16 (byte 2)
31-24 MACSRCADDR2
23-16 MACSRCADDR3
MAC source address bits 31-24 (byte 3)
MAC source address bits 39-32 (byte 4)
MAC source address bits 47-40 (byte 5)
15-8
7-0
MACSRCADDR4
MACSRCADDR5
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EMAC Port Registers
5.37 MAC Hash Address Register 1 (MACHASH1)
The MAC hash registers allow group addressed frames to be accepted on the basis of a hash function of
the address. The hash function creates a 6-bit data value (hash_fun) from the 48-bit destination address
(DA) as follows:
Hash_fun(0)=DA(0) XOR DA(6) XOR DA(12) XOR DA(18) XOR DA(24) XOR DA(30) XOR DA(36) XOR DA(42);
Hash_fun(1)=DA(1) XOR DA(7) XOR DA(13) XOR DA(19) XOR DA(25) XOR DA(31) XOR DA(37) XOR DA(43);
Hash_fun(2)=DA(2) XOR DA(8) XOR DA(14) XOR DA(20) XOR DA(26) XOR DA(32) XOR DA(38) XOR DA(44);
Hash_fun(3)=DA(3) XOR DA(9) XOR DA(15) XOR DA(21) XOR DA(27) XOR DA(33) XOR DA(39) XOR DA(45);
Hash_fun(4)=DA(4) XOR DA(10) XOR DA(16) XOR DA(22) XOR DA(28) XOR DA(34) XOR DA(40) XOR DA(46);
Hash_fun(5)=DA(5) XOR DA(11) XOR DA(17) XOR DA(23) XOR DA(29) XOR DA(35) XOR DA(41) XOR DA(47);
This function is used as an offset into a 64-bit hash table stored in MACHASH1 and MACHASH2 that
indicates whether a particular address should be accepted or not.
Figure 79. MAC Hash Address Register 1 (MACHASH1)
31
15
16
MACHASH1
R/W-0
0
MACHASH1
R/W-0
LEGEND: R/W = Read/Write; -n = value after reset
Table 73. MAC Hash Address Register 1 (MACHASH1) Field Descriptions
Bit
Field
Value Description
31-0
MACHASH1
Least-significant 32 bits of the hash table corresponding to hash values 0 to 31. If a hash table bit is
set, then a group address that hashes to that bit index is accepted.
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5.38 MAC Hash Address Register 2 (MACHASH2)
Figure 80. MAC Hash Address Register 2 (MACHASH2)
31
15
16
0
MACHASH2
R/W-0
MACHASH2
R/W-0
LEGEND: R/W = Read/Write; -n = value after reset
Table 74. MAC Hash Address Register 2 (MACHASH2) Field Descriptions
Bit
Field
Value Description
31-0
MACHASH2
Most-significant 32 bits of the hash table corresponding to hash values 32 to 63. If a hash table bit
is set, then a group address that hashes to that bit index is accepted.
136
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EMAC Port Registers
5.39 Back Off Test Register (BOFFTEST)
Figure 81. Back Off Test Register (BOFFTEST)
31
15
26
25
16
0
Reserved
R-0
RNDNUM
R-0
12
11
10
9
COLLCOUNT
R-0
LEGEND: R = Read only; -n = value after reset
Reserved
TXBACKOFF
R-0
R-0
Table 75. Back Off Test Register (BOFFTEST) Field Descriptions
Bit
Field
Value Description
31-26 Reserved
25-16 RNDNUM
0
Reserved
Back off random number generator. This field allows the Back off Random Number Generator to be
read. Reading this field returns the generator's current value. The value is reset to zero and begins
counting on the clock after the de-assertion of reset.
15-12 COLLCOUNT
11-10 Reserved
Collision count. These bits indicate the number of collisions the current frame has experienced.
Reserved
0
9-0
TXBACKOFF
Back off count. This field allows the current value of the back off counter to be observed for test
purposes. This field is loaded automatically according to the back off algorithm, and is decremented
by one for each slot time after the collision.
137
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5.40 Transmit Pacing Algorithm Test Register (TPACETEST)
Figure 82. Transmit Pacing Algorithm Test Register (TPACETEST)
31
15
16
0
Reserved
R-0
5
4
Reserved
R-0
PACEVAL
R-0
LEGEND: R = Read only; -n = value after reset
Table 76. Transmit Pacing Algorithm Test Register (TPACETEST) Field Descriptions
Bit
31-5
4-0
Field
Value Description
Reserved
PACEVAL
0
Reserved
Pacing register current value. A nonzero value in this field indicates that transmit pacing is active. A
transmit frame collision or deferral causes PACEVAL to be loaded with 1Fh (31); good frame
transmissions (with no collisions or deferrals) cause PACEVAL to be decremented down to 0.
When PACEVAL is nonzero, the transmitter delays four Inter Packet Gaps between new frame
transmissions after each successfully transmitted frame that had no deferrals or collisions. If a
transmit frame is deferred or suffers a collision, the IPG time is not stretched to four times the
normal value. Transmit pacing helps reduce capture effects, which improves overall network
bandwidth.
138
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EMAC Port Registers
5.41 Receive Pause Timer Register (RXPAUSE)
Figure 83. Receive Pause Timer Register (RXPAUSE)
31
15
16
0
Reserved
R-0
PAUSETIMER
R-0
LEGEND: R = Read only; -n = value after reset
Table 77. Receive Pause Timer Register (RXPAUSE) Field Descriptions
Bit
31-16 Reserved
15-0 PAUSETIMER
Field
Value Description
Reserved
Receive pause timer value. These bits allow the contents of the receive pause timer to be
0
observed. The receive pause timer is loaded with FF00h when the EMAC sends an outgoing pause
frame (with pause time of FFFFh). The receive pause timer is decremented at slot time intervals. If
the receive pause timer decrements to 0, then another outgoing pause frame is sent and the
load/decrement process is repeated.
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5.42 Transmit Pause Timer Register (TXPAUSE)
Figure 84. Transmit Pause Timer Register (TXPAUSE)
31
16
0
Reserved
R-0
15
PAUSETIMER
R-0
LEGEND: R = Read only; -n = value after reset
Table 78. Transmit Pause Timer Register (TXPAUSE) Field Descriptions
Bit
31-16 Reserved
15-0 PAUSETIMER
Field
Value Description
0
Reserved
Transmit pause timer value. These bits allow the contents of the transmit pause timer to be
observed. The transmit pause timer is loaded by a received (incoming) pause frame, and then
decremented at slot time intervals down to 0 at which time EMAC transmit frames are again
enabled.
140
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EMAC Port Registers
5.43 MAC Address Low Bytes Register (MACADDRLO)
Figure 85. MAC Address Low Bytes Register (MACADDRLO)
31
15
21
20
19
18
16
0
MATCH
FILT
Reserved
R-0
VALID
R/W-x
CHANNEL
R/W-x
R/W-x
8
7
MACADDR0
R/W-0
MACADDR1
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 79. MAC Address Low Bytes Register (MACADDRLO) Field Descriptions
Bit
Field
Value Description
31-21 Reserved
0
Reserved
20
19
VALID
Address valid bit. This bit should be cleared to zero for unused address RAM locations.
0
1
Address location is not valid and will not be used in determining whether or not an incoming packet
matches or is filtered
Address location is valid and will be used in determining whether or not an incoming packet
matches or is filtered
MATCHFILT
Match or filter bit
0
1
The address will be used (if VALID is set) to determine if the incoming packet address should be
filtered
The address will be used (if VALID is set) to determine if the incoming packet address is a match
18-16 CHANNEL
Channel bit; determines which receive channel a valid address match will be transferred to. The
channel is a don't care if the MATCHFILT bit is cleared to zero.
15-8
7-0
MACADDR0
MACADDR1
MAC address lower 8 bits (byte 0)
MAC address bits 15-8 (byte 1)
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5.44 MAC Address High Bytes Register (MACADDRHI)
Figure 86. MAC Address High Bytes Register (MACADDRHI)
31
15
24
23
16
0
MACADDR2
R/W-0
MACADDR3
R/W-0
8
7
MACADDR4
R/W-0
MACADDR5
R/W-0
LEGEND: R/W = Read/Write; -n = value after reset
Table 80. MAC Address High Bytes Register (MACADDRHI) Field Descriptions
Bit
Field
Value Description
31-24 MACADDR2
23-16 MACADDR3
MAC source address bits 23-16 (byte 2)
MAC source address bits 31-24 (byte 3)
15-8
7-0
MACADDR4
MAC source address bits 39-32 (byte 4)
MAC source address bits 47-40 (byte 5)
MACADDR5
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5.45 MAC Index Register (MACINDEX)
Figure 87. MAC Index Register (MACINDEX)
31
16
0
Reserved
R-0
15
5
4
Reserved
R-0
MACINDEX
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 81. MAC Index Register (MACINDEX) Field Descriptions
Bit
31-5
4-0
Field
Value Description
Reserved
MACINDEX
0
Reserved
MAC address index. The host must write the index into the RX ADDR RAM in the MACINDEX field,
followed by the upper 32-bits of address, followed by the lower 16-bits of address (with control bits).
The 53-bit indexed ram location is written when the low location is written. All 32 address RAM
locations must be initialized prior to enabling packet reception.
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5.46 Transmit Channel 0-7 DMA Head Descriptor Pointer Register (TXnHDP)
Figure 88. Transmit Channel n DMA Head Descriptor Pointer Register (TXnHDP)
31
15
16
0
TXnHDP
R/W-x
TXnHDP
R/W-x
LEGEND: R/W = Read/Write; -n = value after reset
Table 82. Transmit Channel n DMA Head Descriptor Pointer Register (TXnHDP) Field Descriptions
Bit
Field
Value Description
Transmit channel n DMA Head Descriptor pointer. Writing a transmit DMA buffer descriptor address
31-0
TXnHDP
to a head pointer location initiates transmit DMA operations in the queue for the selected channel.
Writing to these locations when they are nonzero is an error (except at reset). Host software must
initialize these locations to zero on reset.
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5.47 Receive Channel 0-7 DMA Head Descriptor Pointer Register (RXnHDP)
Figure 89. Receive Channel n DMA Head Descriptor Pointer Register (RXnHDP)
31
15
16
0
RXnHDP
R/W-x
RXnHDP
R/W-x
LEGEND: R/W = Read/Write; -n = value after reset
Table 83. Receive Channel n DMA Head Descriptor Pointer Register (RXnHDP) Field Descriptions
Bit
Field
Value Description
Receive channel n DMA Head Descriptor pointer. Writing a receive DMA buffer descriptor address
31-0
RXnHDP
to this location allows receive DMA operations in the selected channel when a channel frame is
received. Writing to these locations when they are nonzero is an error (except at reset). Host
software must initialize these locations to zero on reset.
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5.48 Transmit Channel 0-7 Completion Pointer Register (TXnCP)
Figure 90. Transmit Channel n Completion Pointer Register (TXnCP)
31
15
16
0
TXnCP
R/W-x
TXnCP
R/W-x
LEGEND: R/W = Read/Write; -n = value after reset
Table 84. Transmit Channel n Completion Pointer Register (TXnCP) Field Descriptions
Bit
Field
Value Description
Transmit channel n completion pointer register is written by the host with the buffer descriptor
31-0
TXnCP
address for the last buffer processed by the host during interrupt processing. The EMAC uses the
value written to determine if the interrupt should be de-asserted.
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5.49 Receive Channel 0-7 Completion Pointer Register (RXnCP)
Figure 91. Receive Channel n Completion Pointer Register (RXnCP)
31
15
16
0
RXnCP
R/W-x
RXnCP
R/W-x
LEGEND: R/W = Read/Write; -n = value after reset
Table 85. Receive Channel n Completion Pointer Register (RXnCP) Field Descriptions
Bit
Field
Value Description
Receive channel n completion pointer register is written by the host with the buffer descriptor
31-0
RXnCP
address for the last buffer processed by the host during interrupt processing. The EMAC uses the
value written to determine if the interrupt should be de-asserted.
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5.50 Network Statistics Registers
The EMAC has a set of statistics that record events associated with frame traffic. The statistics values are
cleared to zero 38 clocks after the rising edge of reset. When the GMIIEN bit in the MACCONTROL
register is set, all statistics registers are write-to-decrement. The value written is subtracted from the
register value with the result stored in the register. If a value greater than the statistics value is written,
then zero is written to the register (writing FFFF FFFFh clears a statistics location). When the GMIIEN bit
is cleared, all statistics registers are read/write (normal write direct, so writing 0000 0000h clears a
statistics location). All write accesses must be 32-bit accesses.
The statistics interrupt (STATPEND) is issued, if enabled, when any statistics value is greater than or
equal to 8000 0000h. The statistics interrupt is removed by writing to decrement any statistics value
greater than 8000 0000h. The statistics are mapped into internal memory space and are 32-bits wide. All
statistics roll over from FFFF FFFFh to 0000 0000h.
Figure 92. Statistics Register
31
15
16
COUNT
R/W-0
0
COUNT
R/W-0
LEGEND: R/W = Read/Write; -n = value after reset
Table 86. Statistics Register Field Descriptions
Bit
Field
Value Description
Count
31-0
COUNT
5.50.1 Good Receive Frames Register (RXGOODFRAMES)
The total number of good frames received on the EMAC. A good frame is defined as having all of the
following:
•
Any data or MAC control frame that matched a unicast, broadcast, or multicast address, or matched
due to promiscuous mode
•
•
Was of length 64 to RXMAXLEN bytes inclusive
Had no CRC error, alignment error, or code error
See Section 2.5.5 for definitions of alignment, code, and CRC errors. Overruns have no effect on this
statistic.
5.50.2 Broadcast Receive Frames Register (RXBCASTFRAMES)
The total number of good broadcast frames received on the EMAC. A good broadcast frame is defined as
having all of the following:
•
•
•
Any data or MAC control frame that was destined for address FF-FF-FF-FF-FF-FFh only
Was of length 64 to RXMAXLEN bytes inclusive
Had no CRC error, alignment error, or code error
See Section 2.5.5 for definitions of alignment, code, and CRC errors. Overruns have no effect on this
statistic.
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5.50.3 Multicast Receive Frames Register (RXMCASTFRAMES)
The total number of good multicast frames received on the EMAC. A good multicast frame is defined as
having all of the following:
•
Any data or MAC control frame that was destined for any multicast address other than
FF-FF-FF-FF-FF-FFh
•
•
Was of length 64 to RXMAXLEN bytes inclusive
Had no CRC error, alignment error, or code error
See Section 2.5.5 for alignment/code/CRC error definitions. Overruns have no effect on this statistic.
5.50.4 Pause Receive Frames Register (RXPAUSEFRAMES)
The total number of IEEE 802.3X pause frames received by the EMAC (whether acted upon or not). A
pause frame is defined as having all of the following:
•
•
•
•
•
Contained any unicast, broadcast, or multicast address
Contained the length/type field value 88.08h and the opcode 0001h
Was of length 64 to RXMAXLEN bytes inclusive
Had no CRC error, alignment error, or code error
Pause-frames had been enabled on the EMAC (TXFLOWEN bit is set in MACCONTROL).
alignment/code/CRC error definitions. Overruns have no effect on this statistic.
5.50.5 Receive CRC Errors Register (RXCRCERRORS)
The total number of frames received on the EMAC that experienced a CRC error. A frame with CRC
errors is defined as having all of the following:
•
Was any data or MAC control frame that matched a unicast, broadcast, or multicast address, or
matched due to promiscuous mode
•
•
•
Was of length 64 to RXMAXLEN bytes inclusive
Had no alignment or code error
Had a CRC error. A CRC error is defined as having all of the following:
–
–
A frame containing an even number of nibbles
Fails the frame check sequence test
See Section 2.5.5 for definitions of alignment and code errors. Overruns have no effect on this statistic.
5.50.6 Receive Alignment/Code Errors Register (RXALIGNCODEERRORS)
The total number of frames received on the EMAC that experienced an alignment error or code error.
Such a frame is defined as having all of the following:
•
Was any data or MAC control frame that matched a unicast, broadcast, or multicast address, or
matched due to promiscuous mode
•
•
Was of length 64 to RXMAXLEN bytes inclusive
Had either an alignment error or a code error
–
An alignment error is defined as having all of the following:
•
•
A frame containing an odd number of nibbles
Fails the frame check sequence test, if the final nibble is ignored
–
A code error is defined as a frame that has been discarded because the EMACs MRXER pin is
driven with a one for at least one bit-time's duration at any point during the frame's reception.
Overruns have no effect on this statistic.
CRC alignment or code errors can be calculated by summing receive alignment errors, receive code
errors, and receive CRC errors.
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5.50.7 Receive Oversized Frames Register (RXOVERSIZED)
The total number of oversized frames received on the EMAC. An oversized frame is defined as having all
of the following:
•
Was any data or MAC control frame that matched a unicast, broadcast, or multicast address, or
matched due to promiscuous mode
•
•
Was greater than RXMAXLEN in bytes
Had no CRC error, alignment error, or code error
See Section 2.5.5 for definitions of alignment, code/CRC errors. Overruns have no effect on this statistic.
5.50.8 Receive Jabber Frames Register (RXJABBER)
The total number of jabber frames received on the EMAC. A jabber frame is defined as having all of the
following:
•
Was any data or MAC control frame that matched a unicast, broadcast, or multicast address, or
matched due to promiscuous mode
•
•
Was greater than RXMAXLEN bytes long
Had a CRC error, alignment error, or code error
See Section 2.5.5 for definitions of alignment, code, and CRC errors. Overruns have no effect on this
statistic.
5.50.9 Receive Undersized Frames Register (RXUNDERSIZED)
The total number of undersized frames received on the EMAC. An undersized frame is defined as having
all of the following:
•
Was any data frame that matched a unicast, broadcast, or multicast address, or matched due to
promiscuous mode
•
•
Was less than 64 bytes long
Had no CRC error, alignment error, or code error
See Section 2.5.5 for definitions of alignment, code, and CRC errors. Overruns have no effect on this
statistic.
5.50.10 Receive Frame Fragments Register (RXFRAGMENTS)
The total number of frame fragments received on the EMAC. A frame fragment is defined as having all of
the following:
•
•
•
•
Any data frame (address matching does not matter)
Was less than 64 bytes long
Had a CRC error, alignment error, or code error
Was not the result of a collision caused by half duplex, collision based flow control
See Section 2.5.5 for definitions of alignment, code, and CRC errors. Overruns have no effect on this
statistic.
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5.50.11 Filtered Receive Frames Register (RXFILTERED)
The total number of frames received on the EMAC that the EMAC address matching process indicated
should be discarded. Such a frame is defined as having all of the following:
•
•
•
Was any data frame (not MAC control frame) destined for any unicast, broadcast, or multicast address
Did not experience any CRC error, alignment error, code error
The address matching process decided that the frame should be discarded (filtered) because it did not
match the unicast, broadcast, or multicast address, and it did not match due to promiscuous mode.
To determine the number of receive frames discarded by the EMAC for any reason, sum the following
statistics (promiscuous mode disabled):
•
•
•
•
•
•
•
Receive fragments
Receive undersized frames
Receive CRC errors
Receive alignment/code errors
Receive jabbers
Receive overruns
Receive filtered frames
This may not be an exact count because the receive overruns statistic is independent of the other
statistics, so if an overrun occurs at the same time as one of the other discard reasons, then the above
sum double-counts that frame.
5.50.12 Receive QOS Filtered Frames Register (RXQOSFILTERED)
The total number of frames received on the EMAC that were filtered due to receive quality of service
(QOS) filtering. Such a frame is defined as having all of the following:
•
Any data or MAC control frame that matched a unicast, broadcast, or multicast address, or matched
due to promiscuous mode
•
The frame destination channel flow control threshold register (RXnFLOWTHRESH) value was greater
than or equal to the channel's corresponding free buffer register (RXnFREEBUFFER) value
•
•
•
Was of length 64 to RXMAXLEN
RXQOSEN bit is set in RXMBPENABLE
Had no CRC error, alignment error, or code error
See Section 2.5.5 for definitions of alignment, code, and CRC errors. Overruns have no effect on this
statistic.
5.50.13 Receive Octet Frames Register (RXOCTETS)
The total number of bytes in all good frames received on the EMAC. A good frame is defined as having all
of the following:
•
Any data or MAC control frame that matched a unicast, broadcast, or multicast address, or matched
due to promiscuous mode
•
•
Was of length 64 to RXMAXLEN bytes inclusive
Had no CRC error, alignment error, or code error
See Section 2.5.5 for definitions of alignment, code, and CRC errors. Overruns have no effect on this
statistic.
5.50.14 Good Transmit Frames Register (TXGOODFRAMES)
The total number of good frames transmitted on the EMAC. A good frame is defined as having all of the
following:
•
•
•
Any data or MAC control frame that was destined for any unicast, broadcast, or multicast address
Was any length
Had no late or excessive collisions, no carrier loss, and no underrun
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5.50.15 Broadcast Transmit Frames Register (TXBCASTFRAMES)
The total number of good broadcast frames transmitted on the EMAC. A good broadcast frame is defined
as having all of the following:
•
•
•
Any data or MAC control frame destined for address FF-FF-FF-FF-FF-FFh only
Was of any length
Had no late or excessive collisions, no carrier loss, and no underrun
5.50.16 Multicast Transmit Frames Register (TXMCASTFRAMES)
The total number of good multicast frames transmitted on the EMAC. A good multicast frame is defined as
having all of the following:
•
•
•
Any data or MAC control frame destined for any multicast address other than FF-FF-FF-FF-FF-FFh
Was of any length
Had no late or excessive collisions, no carrier loss, and no underrun
5.50.17 Pause Transmit Frames Register (TXPAUSEFRAMES)
The total number of IEEE 802.3X pause frames transmitted by the EMAC. Pause frames cannot underrun
or contain a CRC error because they are created in the transmitting MAC, so these error conditions have
no effect on this statistic. Pause frames sent by software are not included in this count. Since pause
frames are only transmitted in full-duplex mode, carrier loss and collisions have no effect on this statistic.
Transmitted pause frames are always 64-byte multicast frames, so appear in the multicast transmit frames
register and 64 octect frames register statistics.
5.50.18 Deferred Transmit Frames Register (TXDEFERRED)
The total number of frames transmitted on the EMAC that first experienced deferment. Such a frame is
defined as having all of the following:
•
•
•
•
•
Was any data or MAC control frame destined for any unicast, broadcast, or multicast address
Was any size
Had no carrier loss and no underrun
Experienced no collisions before being successfully transmitted
Found the medium busy when transmission was first attempted, so had to wait.
CRC errors have no effect on this statistic.
5.50.19 Transmit Collision Frames Register (TXCOLLISION)
The total number of times that the EMAC experienced a collision. Collisions occur under two
circumstances:
•
When a transmit data or MAC control frame has all of the following:
–
–
–
–
Was destined for any unicast, broadcast, or multicast address
Was any size
Had no carrier loss and no underrun
Experienced a collision. A jam sequence is sent for every non-late collision, so this statistic
increments on each occasion if a frame experiences multiple collisions (and increments on late
collisions).
CRC errors have no effect on this statistic.
•
When the EMAC is in half-duplex mode, flow control is active, and a frame reception begins.
5.50.20 Transmit Single Collision Frames Register (TXSINGLECOLL)
The total number of frames transmitted on the EMAC that experienced exactly one collision. Such a frame
is defined as having all of the following:
•
Was any data or MAC control frame destined for any unicast, broadcast, or multicast address
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•
•
•
Was any size
Had no carrier loss and no underrun
Experienced one collision before successful transmission. The collision was not late.
CRC errors have no effect on this statistic.
5.50.21 Transmit Multiple Collision Frames Register (TXMULTICOLL)
The total number of frames transmitted on the EMAC that experienced multiple collisions. Such a frame is
defined as having all of the following:
•
•
•
•
Was any data or MAC control frame destined for any unicast, broadcast, or multicast address
Was any size
Had no carrier loss and no underrun
Experienced 2 to 15 collisions before being successfully transmitted. None of the collisions were late.
CRC errors have no effect on this statistic.
5.50.22 Transmit Excessive Collision Frames Register (TXEXCESSIVECOLL)
The total number of frames when transmission was abandoned due to excessive collisions. Such a frame
is defined as having all of the following:
•
•
•
•
Was any data or MAC control frame destined for any unicast, broadcast, or multicast address
Was any size
Had no carrier loss and no underrun
Experienced 16 collisions before abandoning all attempts at transmitting the frame. None of the
collisions were late.
CRC errors have no effect on this statistic.
5.50.23 Transmit Late Collision Frames Register (TXLATECOLL)
The total number of frames when transmission was abandoned due to a late collision. Such a frame is
defined as having all of the following:
•
•
•
•
Was any data or MAC control frame destined for any unicast, broadcast, or multicast address
Was any size
Had no carrier loss and no underrun
Experienced a collision later than 512 bit-times into the transmission. There may have been up to 15
previous (non-late) collisions that had previously required the transmission to be re-attempted. The late
collisions statistic dominates over the single, multiple, and excessive collisions statistics. If a late
collision occurs, the frame is not counted in any of these other three statistics.
CRC errors, carrier loss, and underrun have no effect on this statistic.
5.50.24 Transmit Underrun Error Register (TXUNDERRUN)
The number of frames sent by the EMAC that experienced FIFO underrun. Late collisions, CRC errors,
carrier loss, and underrun have no effect on this statistic.
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5.50.25 Transmit Carrier Sense Errors Register (TXCARRIERSENSE)
The total number of frames on the EMAC that experienced carrier loss. Such a frame is defined as having
all of the following:
•
•
•
Was any data or MAC control frame destined for any unicast, broadcast, or multicast address
Was any size
The carrier sense condition was lost or never asserted when transmitting the frame (the frame is not
re-transmitted)
CRC errors and underrun have no effect on this statistic.
5.50.26 Transmit Octet Frames Register (TXOCTETS)
The total number of bytes in all good frames transmitted on the EMAC. A good frame is defined as having
all of the following:
•
•
•
Any data or MAC control frame that was destined for any unicast, broadcast, or multicast address
Was any length
Had no late or excessive collisions, no carrier loss, and no underrun
5.50.27 Transmit and Receive 64 Octet Frames Register (FRAME64)
The total number of 64-byte frames received and transmitted on the EMAC. Such a frame is defined as
having all of the following:
•
•
•
Any data or MAC control frame that was destined for any unicast, broadcast, or multicast address
Did not experience late collisions, excessive collisions, underrun, or carrier sense error
Was exactly 64-bytes long. (If the frame was being transmitted and experienced carrier loss that
resulted in a frame of this size being transmitted, then the frame is recorded in this statistic.)
CRC errors, alignment/code errors, and overruns do not affect the recording of frames in this statistic.
5.50.28 Transmit and Receive 65 to 127 Octet Frames Register (FRAME65T127)
The total number of 65-byte to 127-byte frames received and transmitted on the EMAC. Such a frame is
defined as having all of the following:
•
•
•
Any data or MAC control frame that was destined for any unicast, broadcast, or multicast address
Did not experience late collisions, excessive collisions, underrun, or carrier sense error
Was 65-bytes to 127-bytes long
CRC errors, alignment/code errors, underruns, and overruns do not affect the recording of frames in this
statistic.
5.50.29 Transmit and Receive 128 to 255 Octet Frames Register (FRAME128T255)
The total number of 128-byte to 255-byte frames received and transmitted on the EMAC. Such a frame is
defined as having all of the following:
•
•
•
Any data or MAC control frame that was destined for any unicast, broadcast, or multicast address
Did not experience late collisions, excessive collisions, underrun, or carrier sense error
Was 128-bytes to 255-bytes long
CRC errors, alignment/code errors, underruns, and overruns do not affect the recording of frames in this
statistic.
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5.50.30 Transmit and Receive 256 to 511 Octet Frames Register (FRAME256T511)
The total number of 256-byte to 511-byte frames received and transmitted on the EMAC. Such a frame is
defined as having all of the following:
•
•
•
Any data or MAC control frame that was destined for any unicast, broadcast, or multicast address
Did not experience late collisions, excessive collisions, underrun, or carrier sense error
Was 256-bytes to 511-bytes long
CRC errors, alignment/code errors, underruns, and overruns do not affect the recording of frames in this
statistic.
5.50.31 Transmit and Receive 512 to 1023 Octet Frames Register (FRAME512T1023)
The total number of 512-byte to 1023-byte frames received and transmitted on the EMAC. Such a frame is
defined as having all of the following:
•
•
•
Any data or MAC control frame that was destined for any unicast, broadcast, or multicast address
Did not experience late collisions, excessive collisions, underrun, or carrier sense error
Was 512-bytes to 1023-bytes long
CRC errors, alignment/code errors, and overruns do not affect the recording of frames in this statistic.
5.50.32 Transmit and Receive 1024 to RXMAXLEN Octet Frames Register (FRAME1024TUP)
The total number of 1024-byte to RXMAXLEN-byte frames received and transmitted on the EMAC. Such a
frame is defined as having all of the following:
•
•
•
Any data or MAC control frame that was destined for any unicast, broadcast, or multicast address
Did not experience late collisions, excessive collisions, underrun, or carrier sense error
Was 1024-bytes to RXMAXLEN-bytes long
CRC/alignment/code errors, underruns, and overruns do not affect frame recording in this statistic.
5.50.33 Network Octet Frames Register (NETOCTETS)
The total number of bytes of frame data received and transmitted on the EMAC. Each frame counted has
all of the following:
•
Was any data or MAC control frame destined for any unicast, broadcast, or multicast address (address
match does not matter)
•
Was of any size (including less than 64-byte and greater than RXMAXLEN-byte frames)
Also counted in this statistic is:
•
•
•
Every byte transmitted before a carrier-loss was experienced
Every byte transmitted before each collision was experienced (multiple retries are counted each time)
Every byte received if the EMAC is in half-duplex mode until a jam sequence was transmitted to initiate
flow control. (The jam sequence is not counted to prevent double-counting).
Error conditions such as alignment errors, CRC errors, code errors, overruns, and underruns do not affect
the recording of bytes in this statistic. The objective of this statistic is to give a reasonable indication of
Ethernet utilization.
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5.50.34 Receive FIFO or DMA Start-of-Frame Overruns Register (RXSOFOVERRUNS)
The total number of frames received on the EMAC that had either a FIFO or DMA start-of-frame (SOF)
overrun. An SOF overrun frame is defined as having all of the following:
•
Was any data or MAC control frame that matched a unicast, broadcast, or multicast address, or
matched due to promiscuous mode
•
•
Was of any size (including less than 64-byte and greater than RXMAXLEN-byte frames)
The EMAC was unable to receive it because it did not have the resources to receive it (cell FIFO full or
no DMA buffer available at the start of the frame).
CRC errors, alignment errors, and code errors have no effect on this statistic.
5.50.35 Receive FIFO or DMA Middle-of-Frame Overruns Register (RXMOFOVERRUNS)
The total number of frames received on the EMAC that had either a FIFO or DMA middle-of-frame (MOF)
overrun. An MOF overrun frame is defined as having all of the following:
•
Was any data or MAC control frame that matched a unicast, broadcast, or multicast address, or
matched due to promiscuous mode
•
•
Was of any size (including less than 64-byte and greater than RXMAXLEN-byte frames)
The EMAC was unable to receive it because it did not have the resources to receive it (cell FIFO full or
no DMA buffer available after the frame was successfully started, no SOF overrun)
CRC errors, alignment errors, and code errors have no effect on this statistic.
5.50.36 Receive DMA Start-of-Frame and Middle-of-Frame Overruns Register (RXDMAOVERRUNS)
The total number of frames received on the EMAC that had either a DMA start-of-frame (SOF) overrun or
a DMA middle-of-frame (MOF) overrun. A receive DMA overrun frame is defined as having all of the
following:
•
Was any data or MAC control frame that matched a unicast, broadcast, or multicast address, or
matched due to promiscuous mode
•
•
Was of any size (including less than 64-byte and greater than RXMAXLEN-byte frames)
The EMAC was unable to receive it because it did not have the DMA buffer resources to receive it
(zero head descriptor pointer at the start or during the middle of the frame reception).
CRC errors, alignment errors, and code errors have no effect on this statistic.
156
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Appendix A Glossary
Broadcast MAC Address— A special Ethernet MAC address used to send data to all Ethernet devices
on the local network. The broadcast address is FFh-FFh-FFh-FFh-FFh-FFh. The LSB of the first
byte is odd, qualifying it as a group address; however, its value is reserved for broadcast. It is
classified separately by the EMAC.
Descriptor (Packet Buffer Descriptor)— A small memory structure that describes a larger block of
memory in terms of size, location, and state. Descriptors are used by the EMAC and application to
describe the memory buffers that hold Ethernet data.
Device — In this document, device refers to the TMS320TCI6486/TMS320C6472 digital signal processor.
Ethernet MAC Address (MAC Address)— A unique 6-byte address that identifies an Ethernet device on
the network. In an Ethernet packet, a MAC address is used twice, first to identify the packet's
destination, and second to identify the packet's sender or source. An Ethernet MAC address is
normally specified in hexadecimal, using dashes to separate bytes. For example:
08h-00h-28h-32h-17h-42h.
The first three bytes normally designate the manufacturer of the device. However, when the first
byte of the address is odd (LSB is 1), the address is a group address (broadcast or multicast). The
second bit specifies whether the address is globally or locally administrated (not considered in this
document).
Ethernet Packet (Packet)— An Ethernet packet is the collection of bytes that represents the data portion
of a single Ethernet frame on the wire.
Full Duplex— Full duplex operation allows simultaneous communication between a pair of stations using
point-to-point media (dedicated channel). Full duplex operation does not require that transmitters
defer, nor do they monitor or react to receive activity, as there is no contention for a shared medium
in this mode. Full duplex mode can only be used when all of the following are true:
•
The physical medium is capable of supporting simultaneous transmission and reception without
interference.
•
There are exactly two stations connected with a full duplex point-to-point link. As there is no
contention for use of a shared medium, the multiple access (i.e., CSMA/CD) algorithms are
unnecessary.
•
Both stations on the LAN are capable of, and have been configured to use, full duplex
operation.
The most common configuration envisioned for full duplex operation consists of a central bridge
(also known as a switch) with a dedicated LAN connecting each bridge port to a single device.
Full duplex operation constitutes a proper subset of the MAC functionality required for half duplex
operation.
Half Duplex— In half duplex mode, the CSMA/CD media access method is the means by which two or
more stations share a common transmission medium. To transmit, a station waits (defers) for a
quiet period on the medium; that is, no other station is transmitting. It then sends the intended
message in bit-serial form. If, after initiating a transmission, the message collides with that of
another station, then each transmitting station intentionally transmits for an additional predefined
period to ensure propagation of the collision throughout the system. The station remains silent for a
random amount of time (back off) before attempting to transmit again.
Host— The host is an intelligent system resource that configures and manages each communications
control module. The host is responsible for allocating memory, initializing all data structures, and
responding to port (EMAC) interrupts. In this document, host refers to the
TMS320TCI6486/TMS320C6472 device.
Jabber— A condition wherein a station transmits for a period of time longer than the maximum
permissible packet length, usually due to a fault condition.
157
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Jumbo Packets— Jumbo frames are defined as those packets whose length exceeds the standard
Ethernet MTU, which is 1500 kbytes. For the C64x+ devices, it is recommended not to use packets
exceeding 35K in length. The PHY that you use can place additional limits on to the length of the
packets that you can transfer in a system.
Link— The transmission path between any two instances of generic cabling.
Multicast MAC Address— A class of MAC address that sends a packet to potentially more than one
recipient. A group address is specified by setting the LSB of the first MAC address byte. Thus,
01h-02h-03h-04h-05h-06h is a valid multicast address. Typically, an Ethernet MAC looks for only
certain multicast addresses on a network to reduce traffic load. The multicast address list of
acceptable packets is specified by the application.
Physical Layer and Media Notation— To identify different Ethernet technologies, a simple, three-field,
type notation is used. The Physical Layer type used by the Ethernet is specified by these fields:
<data rate in Mb/s><medium type><maximum segment length (×100m)>
The definitions for the technologies mentioned in this guide are as follows:
Term
Definition
10Base-T
IEEE 802.3 Physical Layer specification for a 10 Mb/s CSMA/CD local area
network over two pairs of twisted-pair telephone wire.
100Base-T
IEEE 802.3 Physical Layer specification for a 100 Mb/s CSMA/CD local
area network over two pairs of Category 5 unshielded twisted-pair (UTP) or
shielded twisted-pair (STP) wire.
1000Base-T
Twisted pair
IEEE 802.3 Physical Layer specification for a 1000 Mb/s CSMA/CD LAN
using four pairs of Category 5 balanced copper cabling.
A cable element that consists of two insulated conductors twisted together
in a regular fashion to form a balanced transmission line.
Port— Ethernet device.
Promiscuous Mode— EMAC receives frames that do not match its address.
158
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Appendix B Revision History
This revision history highlights the technical changes made to the document in this revision.
Table 87. EMAC/MDIO Revision History
See
Additions/Modifications/Deletions
Modified TXINTMASKCLEAR register figure
Modified TXINTMASKCLEAR register table
Modified RXINTMASKSET register figure
Modified RXINTMASKSET register table
Modified RXINTMASKCLEAR register figure
Modified RXINTMASKCLEAR register table
159
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Revision History
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