Intel Network Card 82540EP EM User Manual
PCI/PCI-X Family of Gigabit Ethernet  
Controllers Software Developer’s  
Manual  
82540EP/EM, 82541xx, 82544GC/EI, 82545GM/EM, 82546GB/EB, and  
82547xx  
317453006EN.PDF  
Revision 4.0  
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Revision History  
Date  
Version  
Comments  
Mar 2009  
4.0  
Updated Section 5 (added Table 5-15 “LED Configuration Defaults).  
Oct 2008  
3.9  
Updated section 8.7.4 “Discard PAUSE Frames and Pass MAC Control  
Frames”.  
June 2008  
June 2008  
3.8  
3.7  
Updated EEPROM Word 21h bit descriptions (section 5.6.18).  
Updated Sections 13.4.30 and 13.4.31 (added text stating to use the  
Interrupt Throttling Register (ITR) instead of registers RDTR and RADV for  
applications requiring an interrupt moderation mechanism).  
Jan 2007  
Sept 2007  
May 2007  
Dec 2006  
3.6  
3.5  
3.4  
3.3  
Added a note to sections 13.4.20 and 13.4.21 for the 82547Gi/EI.  
Updated section 13.4.16.  
Updated section 6.4.1. Changed acronym “WCR” to “WUC”.  
Updated Table 13-87. Changed bit 24 settings to:  
0b = Cache line granularity.  
1b = Descriptor granularity.  
June 2006  
April 2006  
3.2  
3.1  
Updated Table 13.47. Changed the default setting of reserved bit 3 from 0b  
to 1b.  
Added bit definitions (bits 9:8) to PHY register PSCON (16d).  
Updated Figure 3.2 (added Receive Queue artwork).  
Changed 81541ER-C0 to 82541ER-CO in Table 5-1.  
Nov 2005  
July 2005  
3.0  
2.5  
Updated Device Control/Status, EEPROM Flash Control & Data, Extended  
Device Control, and TCTL register bit assignments.  
Updated PHY register 00d - 03d, 07d, 09d, 17d - 21d, and 23d bit assign-  
ments.  
Initial Public Release.  
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Note:  
This page is intentionally left blank.  
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Contents  
1
Introduction..................................................................................................................1  
1.1  
1.2  
1.3  
Scope ....................................................................................................................1  
Overview ...............................................................................................................1  
Ethernet Controller Features.................................................................................2  
1.3.1  
1.3.2  
1.3.3  
1.3.4  
1.3.5  
1.3.6  
PCI Features ........................................................................................2  
CSA Features (82547GI/EI Only).........................................................2  
Network Side Features.........................................................................2  
Host Offloading Features .....................................................................3  
Additional Performance Features.........................................................4  
Manageability Features (Not Applicable to the 82544GC/EI or  
82541ER)5  
1.3.7  
1.3.8  
Additional Ethernet Controller Features ...............................................5  
Technology Features............................................................................5  
1.4  
Conventions ..........................................................................................................6  
1.4.1  
1.4.2  
Register and Bit References ................................................................6  
Byte and Bit Designations ....................................................................6  
1.5  
1.6  
Related Documents...............................................................................................6  
Memory Alignment Terminology............................................................................6  
2
Architectural Overview ............................................................................................7  
2.1  
2.2  
2.3  
Introduction............................................................................................................7  
External Architecture.............................................................................................8  
Microarchitecture.................................................................................................10  
2.3.1  
2.3.2  
2.3.3  
2.3.4  
2.3.5  
2.3.6  
2.3.7  
2.3.8  
PCI/PCI-X Core Interface...................................................................10  
82547GI/EI CSA Interface..................................................................11  
DMA Engine and Data FIFO ..............................................................11  
10/100/1000 Mb/s Receive and Transmit MAC Blocks......................12  
MII/GMII/TBI/Internal SerDes Interface Block ....................................12  
10/100/1000 Ethernet Transceiver (PHY) ..........................................13  
EEPROM Interface.............................................................................13  
FLASH Memory Interface...................................................................14  
2.4  
2.5  
2.6  
2.7  
DMA Addressing .................................................................................................14  
Ethernet Addressing............................................................................................15  
Interrupts .............................................................................................................16  
Hardware Acceleration Capability .......................................................................17  
2.7.1  
2.7.2  
Checksum Offloading.........................................................................17  
TCP Segmentation.............................................................................17  
2.8  
Buffer and Descriptor Structure...........................................................................17  
3
Receive and Transmit Description....................................................................19  
3.1  
3.2  
Introduction..........................................................................................................19  
Packet Reception ................................................................................................19  
3.2.1  
3.2.2  
3.2.3  
3.2.4  
Packet Address Filtering ....................................................................19  
Receive Data Storage ........................................................................20  
Receive Descriptor Format.................................................................20  
Receive Descriptor Fetching ..............................................................25  
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Contents  
3.2.5  
3.2.6  
3.2.7  
3.2.8  
3.2.9  
Receive Descriptor Write-Back ..........................................................26  
Receive Descriptor Queue Structure..................................................26  
Receive Interrupts ..............................................................................28  
82544GC/EI Receive Interrupts .........................................................31  
Receive Packet Checksum Offloading...............................................31  
3.3  
Packet Transmission...........................................................................................34  
3.3.1  
3.3.2  
3.3.3  
3.3.4  
3.3.5  
3.3.6  
3.3.7  
Transmit Data Storage .......................................................................35  
Transmit Descriptors ..........................................................................35  
Legacy Transmit Descriptor Format...................................................36  
Transmit Descriptor Special Field Format..........................................40  
TCP/IP Context Transmit Descriptor Format......................................41  
TCP/IP Context Descriptor Layout .....................................................42  
TCP/IP Data Descriptor Format .........................................................46  
3.4  
3.5  
Transmit Descriptor Ring Structure.....................................................................51  
3.4.1  
3.4.2  
3.4.3  
Transmit Descriptor Fetching .............................................................53  
Transmit Descriptor Write-back..........................................................53  
Transmit Interrupts .............................................................................54  
TCP Segmentation..............................................................................................55  
3.5.1  
3.5.2  
3.5.3  
3.5.4  
3.5.5  
3.5.6  
3.5.7  
3.5.8  
3.5.9  
Assumptions.......................................................................................56  
Transmission Process........................................................................56  
TCP Segmentation Performance .......................................................57  
Packet Format....................................................................................57  
TCP Segmentation Indication.............................................................58  
TCP Segmentation Use of Multiple Data Descriptors ........................59  
IP and TCP/UDP Headers..................................................................60  
Transmit Checksum Offloading with TCP Segmentation ...................64  
IP/TCP/UDP Header Updating...........................................................65  
3.6  
IP/TCP/UDP Transmit Checksum Offloading......................................................68  
4
PCI Local Bus Interface.........................................................................................71  
4.1  
PCI Configuration................................................................................................71  
4.1.1  
4.1.2  
4.1.3  
PCI-X Configuration Registers ...........................................................79  
Reserved and Undefined Addresses..................................................82  
Message Signaled Interrupts..............................................................83  
4.2  
4.3  
Commands..........................................................................................................85  
PCI/PCI-X Command Usage...............................................................................87  
4.3.1  
4.3.2  
Memory Write Operations ..................................................................87  
Memory Read Operations ..................................................................89  
4.4  
Cache Line Information.......................................................................................90  
4.4.1 Target Transaction Termination .........................................................91  
4.5  
4.6  
4.7  
Interrupt Assignment (82547GI/EI Only).............................................................91  
LAN Disable ........................................................................................................91  
CardBus Application (82541PI/GI/EI Only) .........................................................92  
5
EEPROM Interface ...................................................................................................93  
5.1  
5.2  
5.3  
General Overview ...............................................................................................93  
Component Identification Via Programming Interface.........................................94  
EEPROM Device and Interface...........................................................................95  
5.3.1  
Software Access.................................................................................96  
5.4  
Signature and CRC Fields ..................................................................................96  
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5.5  
5.6  
EEUPDATE Utility ...............................................................................................97  
5.5.1  
Command Line Parameters ...............................................................97  
EEPROM Address Map.......................................................................................98  
5.6.1  
5.6.2  
5.6.3  
5.6.4  
5.6.5  
5.6.6  
5.6.7  
5.6.8  
Ethernet Address (Words 00h-02h)..................................................103  
Software Compatibility Word (Word 03h).........................................103  
SerDes Configuration (Word 04h)....................................................104  
EEPROM Image Version (Word 05h)...............................................104  
Compatibility Fields (Word 05h - 07h)..............................................104  
PBA Number (Word 08h, 09h) .........................................................104  
Initialization Control Word 1 (Word 0Ah)..........................................105  
Subsystem ID (Word 0Bh)................................................................106  
Subsystem Vendor ID (Word 0Ch)...................................................106  
Device ID (Word 0Dh, 11h) ..............................................................107  
Vendor ID (Word 0Eh)......................................................................107  
Initialization Control Word 2 (Word 0Fh) ..........................................107  
PHY Register Address Data (Words 10h, 11h, and 13h - 1Eh) .......109  
OEM Reserved Words (Words 10h, 11h, 13h - 1Fh) .......................109  
EEPROM Size (Word 12h)...............................................................109  
Common Power (Word 12h).............................................................109  
Software Defined Pins Control (Word 10h, 20h) ..............................109  
CSA Port Configuration 2 (Word 21h)..............................................111  
Circuit Control (Word 21h)................................................................112  
D0 Power (Word 22h high byte).......................................................112  
D3 Power (Word 22h low byte) ........................................................112  
Reserved Words (23h - 2Eh)............................................................112  
Reserved Words (23h - 2Fh)............................................................112  
Management Control (Word 13h, 23h).............................................113  
SMBus Slave Address (Word 14h low byte, 24h low byte) ..............114  
Initialization Control 3 (Word 14h high byte, 24h high byte).............115  
IPv4 Address (Words 15h - 16h and 25h - 26h)...............................116  
5.6.9  
5.6.10  
5.6.11  
5.6.12  
5.6.13  
5.6.14  
5.6.15  
5.6.16  
5.6.17  
5.6.18  
5.6.19  
5.6.20  
5.6.21  
5.6.22  
5.6.23  
5.6.24  
5.6.25  
5.6.26  
5.6.27  
5.6.28  
5.6.29  
5.6.30  
5.6.31  
5.6.32  
5.6.33  
5.6.34  
5.6.35  
5.6.36  
1
IPv6 Address (words 17h - 1Eh and 27h - 2Eh) .............................116  
LED Configuration Defaults (Word 2Fh)...........................................117  
Boot Agent Main Setup Options (Word 30h)....................................117  
Boot Agent Configuration Customization Options (Word 31h).........119  
Boot Agent Configuration Customization Options (Word 32h).........121  
IBA Capabilities (Word 33h).............................................................122  
IBA Secondary Port Configuration (Words 34h-35h) .......................122  
Checksum Word Calculation (Word 3Fh).........................................123  
82546GB/EB Dual-Channel Fiber Wake on LAN (WOL) Mode and  
Functionality (Word 0Ah, 20h)123  
5.6.37  
EEPROM Images.............................................................................123  
5.7  
Parallel FLASH Memory....................................................................................124  
7
FLASH Memory Interface....................................................................................127  
7.1  
7.2  
FLASH Interface Operation...............................................................................127  
FLASH Control and Accesses...........................................................................127  
7.2.1  
7.2.2  
Read Accesses ................................................................................128  
Write Accesses.................................................................................128  
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Contents  
6
Power Management...............................................................................................131  
6.1  
6.2  
6.3  
Introduction to Power Management ..................................................................131  
Assumptions......................................................................................................131  
D3cold support..................................................................................................132  
6.3.1  
6.3.2  
6.3.3  
Power States....................................................................................132  
Timing...............................................................................................134  
PCI Power Management Registers..................................................139  
6.4  
Wakeup.............................................................................................................143  
6.4.1  
6.4.2  
6.4.3  
Advanced Power Management Wakeup..........................................143  
ACPI Power Management Wakeup..................................................144  
Wakeup Packets ..............................................................................145  
8
Ethernet Interface ..................................................................................................155  
8.1  
8.2  
Introduction .......................................................................................................155  
Link Interfaces Overview...................................................................................155  
8.2.1  
8.2.2  
8.2.3  
Internal SerDes Interface/TBI Mode– 1Gb/s ....................................156  
GMII – 1 Gb/s...................................................................................157  
MII – 10/100 Mb/s.............................................................................158  
8.3  
8.4  
Internal Interface ...............................................................................................158  
Duplex Operation ..............................................................................................158  
8.4.1  
8.4.2  
Full Duplex .......................................................................................159  
Half Duplex.......................................................................................159  
8.5  
8.6  
Auto-Negotiation and Link Setup ......................................................................161  
Auto-Negotiation and Link Setup ......................................................................161  
8.6.1  
8.6.2  
8.6.3  
8.6.4  
8.6.5  
Link Configuration in Internal Serdes/TBI Mode...............................162  
Internal GMII/MII Mode.....................................................................165  
Internal SerDes Mode Control Bit Resolution...................................168  
Internal PHY Mode Control Bit Resolution .......................................169  
Loss of Signal/Link Status Indication................................................171  
8.7  
10/100 Mb/s Specific Performance Enhancements ..........................................172  
8.7.1  
8.7.2  
8.7.3  
8.7.4  
8.7.5  
8.7.6  
8.7.7  
Adaptive IFS.....................................................................................172  
Flow Control .....................................................................................173  
MAC Control Frames & Reception of Flow Control Packets............173  
Discard PAUSE Frames and Pass MAC Control Frames................175  
Transmission of PAUSE Frames......................................................176  
Software Initiated PAUSE Frame Transmission...............................176  
External Control of Flow Control Operation......................................176  
9
802.1q VLAN Support...........................................................................................179  
9.1  
802.1q VLAN Packet Format ............................................................................179  
9.1.1 802.1q Tagged Frames....................................................................179  
Transmitting and Receiving 802.1q Packets.....................................................180  
9.2  
9.2.1  
9.2.2  
Adding 802.1q Tags on Transmits ...................................................180  
Stripping 802.1q Tags on Receives .................................................180  
9.3  
802.1q VLAN Packet Filtering...........................................................................180  
10  
Configurable LED Outputs.................................................................................183  
10.1 Configurable LED Outputs ................................................................................183  
10.1.1  
10.1.2  
Selecting an LED Output Source .....................................................183  
Polarity Inversion..............................................................................184  
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10.1.3  
Blink Control.....................................................................................184  
11  
PHY Functionality and Features ......................................................................187  
11.1  
Auto-Negotiation................................................................................................187  
11.1.1  
11.1.2  
11.1.3  
11.1.4  
Overview ..........................................................................................187  
Next Page Exchanges......................................................................188  
Register Update ...............................................................................188  
Status ...............................................................................................189  
11.2  
MDI/MDI-X Crossover (copper only) .................................................................189  
11.2.1  
11.2.2  
Polarity Correction (copper only)......................................................190  
10/100 Downshift (82540EP/EM Only).............................................190  
11.3  
11.4  
Cable Length Detection (copper only)...............................................................191  
PHY Power Management (copper only)............................................................191  
11.4.1  
11.4.2  
11.4.3  
11.4.4  
Link Down – Energy Detect (copper only)........................................191  
D3 State, No Link Required (copper only)........................................192  
D3 Link-Up, Speed-Management Enabled (copper only).................192  
D3 Link-Up, Speed-Management Disabled (copper only)................192  
11.5  
11.6  
Initialization........................................................................................................193  
11.5.1 MDIO Control Mode .........................................................................193  
Determining Link State......................................................................................194  
11.6.1  
11.6.2  
11.6.3  
11.6.4  
False Link.........................................................................................195  
Forced Operation .............................................................................195  
Auto Negotiation...............................................................................196  
Parallel Detection .............................................................................196  
11.7  
Link Criteria .......................................................................................................196  
11.7.1  
11.7.2  
11.7.3  
1000BASE-T ....................................................................................196  
100BASE-TX....................................................................................196  
10BASE-T ........................................................................................197  
11.8  
11.9  
Link Enhancements...........................................................................................197  
11.8.1  
11.8.2  
SmartSpeed .....................................................................................197  
Flow Control .....................................................................................197  
Management Data Interface..............................................................................198  
11.10 Low Power Operation........................................................................................198  
11.10.1 Powerdown via the PHY Register ....................................................199  
11.10.2 Smart Power-Down ..........................................................................199  
11.11 1000 Mbps Operation........................................................................................199  
11.11.1 Introduction.......................................................................................199  
11.11.2 Transmit Functions...........................................................................201  
11.11.3 Transmit FIFO ..................................................................................201  
11.11.4 Receive Functions............................................................................203  
11.12 100 Mbps Operation..........................................................................................204  
11.13 10 Mbps Operation............................................................................................204  
11.13.1 Link Test...........................................................................................205  
11.13.2 10Base-T Link Failure Criteria and Override....................................205  
11.13.3 Jabber ..............................................................................................205  
11.13.4 Polarity Correction............................................................................205  
11.13.5 Dribble Bits.......................................................................................205  
11.14 PHY Line Length Indication...............................................................................205  
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12  
Dual Port Characteristics....................................................................................207  
12.1  
12.2  
Introduction .......................................................................................................207  
Features of Each MAC......................................................................................207  
12.2.1  
12.2.2  
12.2.3  
PCI/PCI-X interface..........................................................................207  
MAC Configuration Register Space .................................................209  
SDP, LED, INT# output ....................................................................209  
12.3  
Shared EEPROM..............................................................................................210  
12.3.1  
12.3.2  
EEPROM Map..................................................................................210  
EEPROM Arbitration ........................................................................210  
12.4  
12.5  
Shared FLASH..................................................................................................211  
12.4.1 FLASH Access Contention...............................................................211  
LAN Disable ......................................................................................................212  
12.5.1  
12.5.2  
12.5.3  
12.5.4  
12.5.5  
12.5.6  
Overview ..........................................................................................212  
Values Sampled on Reset................................................................212  
Multi-Function Advertisement...........................................................213  
Interrupt Use.....................................................................................213  
Power Reporting...............................................................................213  
Summary..........................................................................................214  
13  
Register Descriptions...........................................................................................215  
13.1  
13.2  
Introduction .......................................................................................................215  
Register Conventions........................................................................................215  
13.2.1  
13.2.2  
Memory and I/O Address Decoding .................................................216  
I/O-Mapped Internal Register, Internal Memory, and Flash .............217  
13.3  
13.4  
PCI-X Register Access Split..............................................................................223  
Main Register Descriptions ...............................................................................224  
13.4.1  
13.4.2  
13.4.3  
13.4.4  
13.4.5  
13.4.6  
13.4.7  
13.4.8  
13.4.9  
Device Control Register ...................................................................224  
Device Status Register.....................................................................229  
EEPROM/Flash Control & Data Register.........................................232  
EEPROM Read Register..................................................................234  
Flash Access....................................................................................236  
Extended Device Control Register ...................................................237  
MDI Control Register........................................................................242  
Flow Control Address Low ...............................................................283  
Flow Control Address High...............................................................283  
13.4.10 Flow Control Type ............................................................................284  
13.4.11 VLAN Ether Type .............................................................................284  
13.4.12 Flow Control Transmit Timer Value..................................................285  
13.4.13 Transmit Configuration Word Register.............................................286  
13.4.14 Receive Configuration Word Register..............................................287  
13.4.15 LED Control......................................................................................289  
13.4.16 Packet Buffer Allocation ...................................................................292  
13.4.17 Interrupt Cause Read Register.........................................................293  
13.4.18 Interrupt Throttling Register..............................................................295  
13.4.19 Interrupt Cause Set Register............................................................296  
13.4.20 Interrupt Mask Set/Read Register....................................................297  
13.4.21 Interrupt Mask Clear Register ..........................................................298  
13.4.22 Receive Control Register .................................................................300  
13.4.23 Flow Control Receive Threshold Low...............................................304  
13.4.24 Flow Control Receive Threshold High..............................................305  
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13.4.25 Receive Descriptor Base Address Low............................................306  
13.4.26 Receive Descriptor Base Address High ...........................................306  
13.4.27 Receive Descriptor Length...............................................................307  
13.4.28 Receive Descriptor Head .................................................................307  
13.4.29 Receive Descriptor Tail ....................................................................308  
13.4.30 Receive Delay Timer Register..........................................................308  
13.4.31 Receive Interrupt Absolute Delay Timer...........................................309  
13.4.32 Receive Small Packet Detect Interrupt.............................................310  
13.4.33 Transmit Control Register ................................................................310  
13.4.34 Transmit IPG Register......................................................................312  
13.4.35 Adaptive IFS Throttle - AIT...............................................................314  
13.4.36 Transmit Descriptor Base Address Low...........................................315  
13.4.37 Transmit Descriptor Base Address High ..........................................316  
13.4.38 Transmit Descriptor Length..............................................................316  
13.4.39 Transmit Descriptor Head ................................................................317  
13.4.40 Transmit Descriptor Tail ...................................................................318  
13.4.41 Transmit Interrupt Delay Value.........................................................318  
13.4.42 TX DMA Control (82544GC/EI only) ................................................319  
13.4.43 Transmit Descriptor Control .............................................................319  
13.4.44 Transmit Absolute Interrupt Delay Value..........................................321  
13.4.45 TCP Segmentation Pad And Minimum Threshold............................322  
13.4.46 Receive Descriptor Control ..............................................................324  
13.4.47 Receive Checksum Control..............................................................325  
Filter Registers ..................................................................................................327  
13.5  
13.6  
13.5.1  
13.5.2  
13.5.3  
13.5.4  
Multicast Table Array........................................................................327  
Receive Address Low.......................................................................329  
Receive Address High......................................................................329  
VLAN Filter Table Array ...................................................................330  
Wakeup Registers.............................................................................................331  
13.6.1  
13.6.2  
13.6.3  
13.6.4  
13.6.5  
13.6.6  
13.6.7  
13.6.8  
13.6.9  
Wakeup Control Register .................................................................331  
Wakeup Filter Control Register ........................................................332  
Wakeup Status Register...................................................................333  
IP Address Valid...............................................................................335  
IPv4 Address Table..........................................................................336  
IPv6 Address Table..........................................................................337  
Wakeup Packet Length ....................................................................338  
Wakeup Packet Memory (128 Bytes)...............................................338  
Flexible Filter Length Table..............................................................338  
13.6.10 Flexible Filter Mask Table ................................................................339  
13.6.11 Flexible Filter Value Table................................................................340  
Statistics Registers............................................................................................340  
13.7  
13.7.1  
13.7.2  
13.7.3  
13.7.4  
13.7.5  
13.7.6  
13.7.7  
13.7.8  
13.7.9  
CRC Error Count..............................................................................341  
Alignment Error Count......................................................................341  
Symbol Error Count..........................................................................342  
RX Error Count.................................................................................342  
Missed Packets Count......................................................................343  
Single Collision Count ......................................................................343  
Excessive Collisions Count ..............................................................344  
Multiple Collision Count....................................................................344  
Late Collisions Count .......................................................................345  
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13.7.10 Collision Count .................................................................................345  
13.7.11 Defer Count......................................................................................346  
13.7.12 Transmit with No CRS......................................................................346  
13.7.13 Sequence Error Count......................................................................347  
13.7.14 Carrier Extension Error Count..........................................................347  
13.7.15 Receive Length Error Count.............................................................348  
13.7.16 XON Received Count.......................................................................348  
13.7.17 XON Transmitted Count...................................................................349  
13.7.18 XOFF Received Count .....................................................................349  
13.7.19 XOFF Transmitted Count .................................................................349  
13.7.20 FC Received Unsupported Count ....................................................350  
13.7.21 Packets Received (64 Bytes) Count.................................................350  
13.7.22 Packets Received (65-127 Bytes) Count .........................................351  
13.7.23 Packets Received (128-255 Bytes) Count .......................................351  
13.7.24 Packets Received (256-511 Bytes) Count .......................................352  
13.7.25 Packets Received (512-1023 Bytes) Count .....................................352  
13.7.26 Packets Received (1024 to Max Bytes) Count.................................353  
13.7.27 Good Packets Received Count ........................................................353  
13.7.28 Broadcast Packets Received Count.................................................354  
13.7.29 Multicast Packets Received Count...................................................354  
13.7.30 Good Packets Transmitted Count ....................................................355  
13.7.31 Good Octets Received Count...........................................................355  
13.7.32 Good Octets Transmitted Count.......................................................356  
13.7.33 Receive No Buffers Count................................................................356  
13.7.34 Receive Undersize Count.................................................................357  
13.7.35 Receive Fragment Count .................................................................357  
13.7.36 Receive Oversize Count...................................................................358  
13.7.37 Receive Jabber Count......................................................................358  
13.7.38 Management Packets Received Count............................................359  
1 ........................................................360  
13.7.39 Management Packets Dropped Count  
13.7.40 Management Pkts Transmitted Count..............................................360  
13.7.41 Total Octets Received......................................................................360  
13.7.42 Total Octets Transmitted..................................................................361  
13.7.43 Total Packets Received....................................................................362  
13.7.44 Total Packets Transmitted................................................................362  
13.7.45 Packets Transmitted (64 Bytes) Count.............................................363  
13.7.46 Packets Transmitted (65-127 Bytes) Count .....................................363  
13.7.47 Packets Transmitted (128-255 Bytes) Count ...................................364  
13.7.48 Packets Transmitted (256-511 Bytes) Count ...................................364  
13.7.49 Packets Transmitted (512-1023 Bytes) Count .................................365  
13.7.50 Packets Transmitted (1024 Bytes or Greater) Count .......................365  
13.7.51 Multicast Packets Transmitted Count...............................................366  
13.7.52 Broadcast Packets Transmitted Count.............................................366  
13.7.53 TCP Segmentation Context Transmitted Count...............................367  
13.7.54 TCP Segmentation Context Transmit Fail Count .............................367  
Diagnostics Registers .......................................................................................368  
13.8  
13.8.1  
13.8.2  
13.8.3  
13.8.4  
Receive Data FIFO Head Register...................................................368  
Receive Data FIFO Tail Register .....................................................368  
Receive Data FIFO Head Saved Register .......................................369  
Receive Data FIFO Tail Saved Register ..........................................369  
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13.8.5  
13.8.6  
13.8.7  
13.8.8  
13.8.9  
Receive Data FIFO Packet Count....................................................370  
Transmit Data FIFO Head Register..................................................370  
Transmit Data FIFO Tail Register ....................................................371  
Transmit Data FIFO Head Saved Register ......................................371  
Transmit Data FIFO Tail Saved Register .........................................372  
13.8.10 Transmit Data FIFO Packet Count...................................................372  
13.8.11 Packet Buffer Memory......................................................................373  
14  
General Initialization and Reset Operation..................................................375  
14.1  
14.2  
14.3  
14.4  
14.5  
Introduction........................................................................................................375  
Power Up State .................................................................................................375  
General Configuration .......................................................................................375  
Receive Initialization..........................................................................................376  
Transmit Initialization.........................................................................................377  
14.5.1  
14.5.2  
14.5.3  
14.5.4  
14.5.5  
Signal Interface ................................................................................380  
GMII/MII Features not Supported.....................................................381  
Avoiding GMII Test Mode(s).............................................................382  
MAC Configuration...........................................................................382  
Link Setup ........................................................................................383  
14.6  
14.7  
14.8  
PHY Initialization (10/100/1000 Mb/s Copper Media) .......................................384  
Reset Operation ................................................................................................385  
Initialization of Statistics ....................................................................................388  
15  
Diagnostics and Testability ...............................................................................389  
15.1  
Diagnostics........................................................................................................389  
15.1.1  
15.1.2  
15.1.3  
FIFO State........................................................................................389  
FIFO Data.........................................................................................389  
Loopback..........................................................................................389  
15.2  
Testability ..........................................................................................................390  
15.2.1  
15.2.2  
15.2.3  
15.2.4  
EXTEST Instruction..........................................................................391  
SAMPLE/PRELOAD Instruction.......................................................391  
IDCODE Instruction..........................................................................391  
BYPASS Instruction .........................................................................391  
A
B
Appendix (Changes From 82544EI/82544GC) ............................................393  
Appendix (82540EP/EM and 82545GM/EM Differences).........................395  
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Introduction  
1
1.1  
Scope  
This document serves as a software developer’s manual for 82546GB/EB, 82545GM/EM,  
82544GC/EI, 82541(PI/GI/EI), 82541ER, 82547GI/EI, and 82540EP/EM Gigabit Ethernet  
Controllers. Throughout this manual references are made to the PCI/PCI-X Family of Gigabit  
Ethernet Controllers or Ethernet controllers. Unless specifically noted, these references apply to all  
the Ethernet controllers listed above.  
1.2  
Overview  
The PCI/PCI-X Family of Gigabit Ethernet Controllers are highly integrated, high-performance  
Ethernet LAN devices for 1000 Mb/s, 100 Mb/s and 10 Mb/s data rates. They are optimized for  
LAN on Motherboard (LOM) designs, enterprise networking, and Internet appliances that use the  
Peripheral Component Interconnect (PCI) and PCI-X bus.  
Note: The 82541xx and 82540EP/EM do not support the PCI-X bus.  
The 82547GI(EI) connects to the motherboard chipset through a Communications Streaming  
Architecture (CSA) port. CSA is designed for low memory latency and higher performance than a  
comparable PCI interface.  
The remaining Ethernet controllers provide a 32-/64-bit, 33/66 MHz direct interface to the PCI  
Local Bus Specification (revision 2.2 or 2.3), as well as the emerging PCI-X extension to the PCI  
Local Bus (revision 1.0a).  
The Ethernet controllers provide an interface to the host processor by using on-chip command and  
status registers and a shared host memory area, set up mainly during initialization. The controllers  
provide a highly optimized architecture to deliver high performance and PCI/CSA/PCI-X bus  
efficiency. By implementing hardware acceleration capabilities, the controllers enable offloading  
various tasks such as TCP/UDP/IP checksum calculations from the host processor. They also  
minimize I/O accesses and interrupts required to manage the Ethernet controllers and provide a  
highly configurable design that can be used effectively in various environments.  
The PCI/PCI-X Family of Gigabit Ethernet Controllers handle all IEEE 802.3 receive and transmit  
MAC functions. They contain fully integrated physical-layer circuitry for 1000 Base-T, 100 Base-  
TX, and 10 Base-T applications (IEEE 802.3, 802.3u, and 802.3ab) as well as on-chip Serializer/  
Deserializer (SerDes)1 functionality that fully complies with IEEE 802.3z PCS.  
1. The 82541xx, 82547GI/EI, and 82540EP/EM do not support any SerDes functionality.  
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Introduction  
For the 82544GC/EI, when connected to an appropriate SerDes, it can alternatively provide an  
Ethernet interface for 1000 Base-SX or LX applications (IEEE 802.3z).  
Note: The 82546EB/82545EM is SerDes PICMG 2.16 compliant. The 82546GB/82545GM is SerDes  
PICMG 3.1 compliant.  
82546GB/EB Ethernet controllers also provide features in an integrated dual-port solution  
comprised of two distinct MAC/PHY instances. As a result, they appear as multi-function PCI  
devices containing two identically-functioning Ethernet controllers. See Section 12 for details.  
1.3  
Ethernet Controller Features  
This section describes the features of the PCI/PCI-X Family of Gigabit Ethernet Controllers.  
1.3.1  
PCI Features  
• 32/64-bit 33/66 MHz, PCI Rev 2.3 and PCI-X 1.0a compliant Host interface (82546GB/  
82545GM)  
• 32/64-bit 33/66 MHz, PCI Rev 2.2 and PCI-X 1.0a compliant Host interface (82546EB,  
82545EM, and 82544GC/EI)  
• 32/64-bit 33/66 MHz, PCI Rev 2.3 compliant Host interface (82541xx)  
• 32/64-bit 33/66 MHz, PCI Rev 2.2 compliant Host interface (82540EP/EM)  
• 64-bit addressing for systems with more than 4 GB of physical memory  
• Efficient PCI bus master operation  
• Command usage optimization for advanced PCI commands  
1.3.2  
1.3.3  
CSA Features (82547GI/EI Only)  
• Uses dedicated port for client LAN controller directly on an MCH device  
• High-speed interface with twice the peak bandwidth of a 32-bit 33 MHz PCI bus  
• PCI power management registers recognized by the MCH  
• Interface only uses 13 signals  
Network Side Features  
• Auto-Negotiation and Link Setup  
— Automatic link configuration including speed, duplex and flow control under IEEE  
802.3ab for copper media  
— For GMII/MII mode, the driver complies with the IEEE 802.3ab standard requirements  
for speed, duplex, and flow control Auto-Negotiation capabilities  
• Supports half and full duplex operation at 10 Mb/s and 100 Mb/s speeds while working with  
the internal PHY  
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• IEEE 802.3x compliant flow control support  
— Enables control of the transmission of Pause packets through software or hardware  
triggering  
— Provides indications of receive FIFO status  
• State-of-the-art internal transceiver (PHY) with DSP architecture implementation  
— Digital adaptive equalization and crosstalk  
— Echo and crosstalk cancellation  
— Automatic MDI/MDI-X crossover at all speeds and compensation for cable length  
— Media Independent Interfaces (MII) IEEE 802.3e for supporting 10/10BASE-T  
transceivers  
• Integrated dual-port solution comprised of two distinct MAC/PHY instances (82546GB/EB)  
• Provides on-chip IEEE 802.3z PCS SerDes functionality (82546GB/EB and 82545GM/EM)  
1.3.4  
Host Offloading Features  
• Receive and transmit IP and TCP/UDP checksum offloading capabilities  
• Transmit TCP Segmentation (operating system support required)  
• Packet filtering based on checksum errors  
• Support for various address filtering modes:  
— 16 exact matches (unicast, or multicast)  
— 4096-bit hash filter for multicast frames  
— Promiscuous, unicast and promiscuous multicast transfer modes  
• IEEE 802.1q VLAN support1  
— Ability to add and strip IEEE 802.1q VLAN tags  
— Packet filtering based on VLAN tagging, supporting 4096 tags  
• SNMP and RMON statistic counters  
• Support for IPv6 including (not applicable to the 82544GC/EI):  
— IP/TCP and IP/UDP receive checksum offload  
— Wake up filters  
— TCP segmentation  
1. Not applicable to the 82541ER.  
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Introduction  
1.3.5  
Additional Performance Features  
• Provides adaptive Inter Frame Spacing (IFS) capability, enabling collision reduction in half  
duplex networks (82544GC/EI)  
• Programmable host memory receive buffers (256 B to 16 KB)  
• Programmable cache line size from 16 B to 128 B for efficient usage of PCI bandwidth  
• Implements a total of 64 KB (40 KB for the 82547GI/EI) of configurable receive and transmit  
data FIFOs. Default allocation is 48 KB for the receive data FIFO and 16 KB for the transmit  
data FIFO  
• Descriptor ring management hardware for transmit and receive. Optimized descriptor fetching  
and write-back mechanisms for efficient system memory and PCI bandwidth usage  
• Provides interrupt coalescing to reduce the number of interrupts generated by receive and  
transmit operations (82544GC/EI)  
• Supports reception and transmission of packets with length up to 16 KB  
• New intelligent interrupt generation features to enhance driver performance (not applicable to  
the 82544GC/EI):  
— Packet interrupt coalescing timers (packet timers) and absolute-delay interrupt timers for  
both transmit and receive operation  
— Short packet detection interrupt for improved response time to TCP acknowledges  
— Transmit Descriptor Ring “Low” signaling  
— Interrupt throttling control to limit maximum interrupt rate and improve CPU utilization  
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Introduction  
1.3.6  
1.3.7  
Manageability Features (Not Applicable to the 82544GC/EI or  
82541ER)  
• Manageability support for ASF 1.0 and AoL 2.0 by way of SMBus 2.0 interface and either:  
— TCO mode SMBus-based management packet transmit / receive support  
— Internal ASF-compliant TCO controller  
Additional Ethernet Controller Features  
• Implements ACPI1 register set and power down functionality supporting D0 and D3 states  
• Supports Wake on LAN (WoL)1  
• Provides four wire serial EEPROM interface for loading product configuration information  
— Allows use of either 3.3 V dc or 5 V dc powered EEPROM  
• Provides external parallel interface for up to 512 KB of FLASH memory for support of Pre-  
Boot Execution Environment (PXE)  
• Provides seven general purpose user mode pins  
• Provides Activity and Link LED indications  
• Supports little-endian byte ordering for 32- and 64-bit systems  
• Provides loopback capabilities under TBI (82544GC/EI)2 (internal SerDes for the 82546GB/  
EB and 82545GM/EM) and GMII/MII modes of operation  
• Provides IEEE JTAG boundary scan support  
• Four programmable LED outputs (Not applicable to the 82544GC/EI).  
— For the 82546GB/EB, four programmable LED outputs for each port  
• Detection and improved power-management with LAN cable unconnected (82546GB/EB)  
1.3.8  
Technology Features  
• Implemented in 0.15CMOS process (0.13for the 82541xx and 82547GI/EI)  
• Packaged in 364 PBGA.  
— For the 82544EI, packaged in 416 PBGA.  
— For the 82540EP/EM, 82541xx, and 82547GI/EI, packaged in 196 PBGA.  
• Implemented in low power (3.3 V dc or 5 V dc compatible PCI signaling) CMOS process  
1. Not applicable to the 82541ER.  
2. Not applicable to the 82541xx, 82547GI/EI or 82540EP/EM.  
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Introduction  
1.4  
Conventions  
This document uses notes that call attention to important comments:  
Note: Indicates details about the hardware’s operations that are not immediately obvious. Read these  
notes to get information about exceptions, unusual situations, and additional explanations of some  
PCI/PCI-X Family of Gigabit Ethernet Controller features.  
1.4.1  
1.4.2  
Register and Bit References  
This document refers to Ethernet controller register names using all capital letters. To refer to a  
specific bit in a register the convention REGISTER.BIT is used. For example, CTRL.ASDE refers  
to the Auto-Speed Detection Enable bit in the Device Control Register (CTRL).  
Byte and Bit Designations  
This document uses “B” to abbreviate quantities of bytes. For example, a 4 KB represents 4096  
bytes. Similarly, “b” is used to represent quantities of bits. For example, 100 Mb/s represents 100  
Megabits per second.  
1.5  
1.6  
Related Documents  
• IEEE Std. 802.3, 2000 Edition. Incorporates various IEEE standards previously published  
separately.  
• PCI Local Bus Specification, Revision 2.2 and 2.3, PCI Local Bus Special Interest Group.  
Memory Alignment Terminology  
Some PCI/PCI-X Family of Gigabit Ethernet Controller data structures have special memory  
alignment requirements. This implies that the starting physical address of a data structure must be  
aligned as specified in this manual. The following terms are used for this purpose:  
• BYTE alignment: Implies that the physical addresses can be odd or even. Examples:  
0FECBD9A1h, 02345ADC6h.  
• WORD alignment: Implies that physical addresses must be aligned on even boundaries. For  
example, the last nibble of the address can only end in 0, 2, 4, 6, 8, Ah, Ch, or Eh  
(0FECBD9A2h).  
• DWORD (Double-Word) alignment: Implies that the physical addresses can only be aligned  
on 4-byte boundaries. For example, the last nibble of the address can only end in 0, 4, 8, or Ch  
(0FECBD9A8h).  
• QWORD (Quad-Word) alignment: Implies that the physical addresses can only be aligned on  
8-byte boundaries. For example, the last nibble of the address can only end in 0 or 8  
(0FECBD9A8h).  
• PARAGRAPH alignment: Implies that the physical addresses can only be aligned on 16-byte  
boundaries. For example, the last nibble must be a 0 (02345ADC0h).  
6
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Architectural Overview  
2
2.1  
Introduction  
This section provides an overview of the PCI/PCI-X Family of Gigabit Ethernet Controllers. The  
following sections give detailed information about the Ethernet controller’s functionality, register  
description, and initialization sequence. All major interfaces of the Ethernet controllers are  
described in detail.  
The following principles shaped the design of the PCI/PCI-X Family of Gigabit Ethernet  
Controllers:  
1. Provide an Ethernet interface containing a 10/100/1000 Mb/s PHY that also supports 1000  
Base-X implementations.  
2. Provide the highest performance solution possible, based on the following:  
— Provide direct access to all memory without using mapping registers  
— Minimize the PCI target accesses required to manage the Ethernet controller  
— Minimize the interrupts required to manage the Ethernet controller  
— Off-load the host processor from simple tasks such as TCP checksum calculations  
— Maximize PCI efficiency and performance  
— Use mixed signal processing to assure physical layer characteristics surpass specifications  
for UTP copper media  
3. Provide a simple software interface for basic operations.  
4. Provide a highly configurable design that can be used effectively in different environments.  
The PCI/PCI-X Family of Gigabit Ethernet Controllers architecture is a derivative of the 82542  
and 82543 designs. They take the MAC functionality and integrated copper PHY from their  
predecessors and adds SMBus-based manageability and integrated ASF controller functionality to  
1
the MAC . In addition, the 82546GB/EB features this architecture in an integrated dual-port  
solution comprised of two distinct MAC/PHY instances.  
1. Not applicable to the 82544GC/EI or 82541ER.  
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Architectural Overview  
2.2  
External Architecture  
Figure 2-1 shows the external interfaces to the 82546GB/EB.  
MDI  
Interface A  
MDI  
Interface B  
1000Base-T PHY Interfaces  
Design for  
Test Interface  
10/100/1000  
PHY  
10/100/1000  
PHY  
SMBus  
Interface  
External  
TBI Interface  
GMII/  
MII  
GMII/  
MII  
MDIO  
MDIO  
EEPROM  
Interface  
Device  
Flash Interface  
Device  
Function 0  
MAC/Controller  
(LAN A)  
Function 1  
MAC/Controller  
(LAN B)  
LEDs  
LEDs  
Software  
Defined Pins  
Software  
Defined Pins  
PCI (64-bit, 33/66 MHz)/PCI-X (133 MHz)  
Figure 2-1. 82546GB/EB External Interface  
Figure 2-2 shows the external interfaces to the 82545GM/EM, 82544GC/EI, 82540EP/EM, and  
82541xx.  
MDI  
Interface  
1000Base-T PHY Interface  
Design for  
10/100/1000  
Test Interface  
PHY  
SMBus  
Interface  
External  
TBI Interface  
GMII/  
MII  
MDIO  
EEPROM  
Interface  
(82545GM/EM only)  
Flash Interface  
Device  
Function 0  
MAC/Controller  
LEDs  
Software  
Defined Pins  
PCI (64-bit, 33/66 MHz)/PCI-X (133 MHz)  
Note: 82540EP/EM and 82541xx do not support PCI-X; 82544GC/EI and 82541ER do not support SMBus interface  
Figure 2-2. 82545GM/EM, 82544GC/EI, 82540EP/EM, and 82541xx External Interface  
8
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Architectural Overview  
Figure 2-3 shows the external interfaces to the 82547GI/EI.  
CSA Port  
PCI Core  
EEPROM  
FLASH  
Slave  
Access  
Logic  
DMA Function  
Descriptor Management  
40KB  
Packet  
RAM  
RX Filters  
(Perfect,  
Multicast,  
VLAN)  
Control  
Status  
Logic  
TX/RX MAC  
CSMA/CD  
VLA  
N
Statistics  
8 bits  
8 bits  
Management  
Interface  
Trellis Viterbi  
Encoder/Decoder  
Side-stream  
Scrambler/  
Descrambler  
PHY  
Control  
4 bits  
4 bits  
ECHO, NEXT,  
FEXT  
Cancellers  
4DPAM5  
Encoder  
AGC, A/D  
Timing  
Recovery  
Pulse Shaper,  
DAC, Filter  
Hybrid  
Line Driver  
Media Dependent Interface  
Figure 2-3. 82547GI(EI) External Interface  
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Architectural Overview  
2.3  
Microarchitecture  
Compared to its predecessors, the PCI/PCI-X Family of Gigabit Ethernet Controller’s MAC adds  
improved receive-packet filtering to support SMBus-based manageability, as well as the ability to  
transmit SMBus-based manageability packets. In addition, an ASF-compliant TCO controller is  
integrated into the controller’s MAC for reduced-cost basic ASF manageability.  
Note: The 82544GC/EI and 82541ER do not support SMBus-based manageability.  
For the 82546GB/EB, this new functionality is packaged in an integrated dual-port combination.  
The architecture includes two instances of both the MAC and PHY along with a single PCI/PCI-X  
interface. As a result, each of the logical LAN devices appear as a distinct PCI/PCI-X bus device.  
The following sections describe the hardware building blocks. Figure 2-4 shows the internal  
microarchitecture.  
2.3.1  
PCI/PCI-X Core Interface  
The PCI/PCI-X core provides a complete glueless interface to a 33/66 MHz, 32/64-bit PCI bus or a  
33/66/133 MHz, 32/64 bit PCI-X bus. It is compliant with the PCI Bus Specification Rev 2.2 or 2.3  
and the PCI-X Specification Rev. 1.0a. The Ethernet controllers provide 32 or 64 bits of addressing  
and data, and the complete control interface to operate on a 32-bit or 64-bit PCI or PCI-X bus. In  
systems with a dedicated bus for the Ethernet controller, this provides sufficient bandwidth to  
support sustained 1000 Mb/s full-duplex transfer rates. Systems with a shared bus (especially the  
32-bit wide interface) might not be able to maintain 1000 Mb/s, but can sustain multiple hundreds  
of Mbps.  
Host Arbiter  
TX MAC  
TX  
(10/100/  
Link I/F  
Switch  
1000 Mb)  
GMII/  
MII  
DMA  
Engine  
RX MAC  
(10/100/  
1000 Mb)  
PCI/  
PCI-X  
Core  
PCI Interface  
Packet/  
Manageability  
Filter  
MDIO  
Packet  
Buffer  
ASF  
Manageability  
MDIO  
RMON  
Statistics  
SM Bus  
EEPROM  
Flash  
Figure 2-4. Internal Architecture Block Diagram  
10  
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Architectural Overview  
When the Ethernet controller serves as a PCI target, it follows the PCI configuration specification,  
which allows all accesses to it to be automatically mapped into free memory and I/O space at  
initialization of the PCI system.  
When processing transmit and receive frames, the Ethernet controller operates as master on the PCI  
bus. As a master, transaction burst length on the PCI bus is determined by several factors, including  
the PCI latency timer expiration, the type of bus transfer being made, the size of the data transfer,  
and whether the data transfer is initiated by receive or transmit logic.  
The PCI/PCI-X bus interfaces to the DMA engine.  
2.3.2  
2.3.3  
82547GI/EI CSA Interface  
CSA is derived from the Intel® Hub Architecture. The 82547EI Controller CSA port consists of 11  
data and control signals, two strobes, a 66 MHz clock, and driver compensation resistor connec-  
tions. The operating details of these signals and the packet data protocol that accompanies them are  
proprietary. The CSA port has a theoretical bandwidth of 266 MB/s — approximately twice the  
peak bandwidth of a 32-bit 33 MHz PCI bus.  
The CSA port architecture is invisible to both system software and the operating system, allowing  
conventional PCI-like configuration.  
DMA Engine and Data FIFO  
The DMA engine handles the receive and transmit data and descriptor transfers between the host  
memory and the on-chip memory.  
In the receive path, the DMA engine transfers the data stored in the receive data FIFO buffer to the  
receive buffer in the host memory, specified by the address in the descriptor. It also fetches and  
writes back updated receive descriptors to host memory.  
In the transmit path, the DMA engine transfers data stored in the host memory buffers to the  
transmit data FIFO buffer. It also fetches and writes back updated transmit descriptors.  
The Ethernet controller data FIFO block consists of a 64 KB (40 KB for the 82547GI/EI) on-chip  
buffer for receive and transmit operation. The receive and transmit FIFO size can be allocated  
based on the system requirements. The FIFO provides a temporary buffer storage area for frames  
as they are received or transmitted by the Ethernet controller.  
The DMA engine and the large data FIFOs are optimized to maximize the PCI bus efficiency and  
reduce processor utilization by:  
• Mitigating instantaneous receive bandwidth demands and eliminating transmit underruns by  
buffering the entire out-going packet prior to transmission  
• Queuing transmit frames within the transmit FIFO, allowing back-to-back transmission with  
the minimum interframe spacing  
• Allowing the Ethernet controller to withstand long PCI bus latencies without losing incoming  
data or corrupting outgoing data  
• Allowing the transmit start threshold to be tuned by the transmit FIFO threshold. This  
adjustment to system performance is based on the available PCI bandwidth, wire speed, and  
latency considerations  
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Architectural Overview  
• Offloading the receiving and transmitting IP and TCP/UDP checksums  
• Directly retransmitting from the transmit FIFO any transmissions resulting in errors (collision  
detection, data underrun), thus eliminating the need to re-access this data from host memory  
2.3.4  
10/100/1000 Mb/s Receive and Transmit MAC Blocks  
The controller’s CSMA/CD unit handles all the IEEE 802.3 receive and transmit MAC functions  
while interfacing between the DMA and TBI/internal SerDes/MII/GMII interface block. The  
CSMA/CD unit supports IEEE 802.3 for 10 Mb/s, IEEE 802.3u for 100 Mb/s and IEEE 802.3z and  
IEEE 802.3ab for 1000 Mb/s.  
The Ethernet controller supports half-duplex 10/100 Mb/s MII or 1000 Mb/s GMII mode and all  
aspects of the above specifications in full-duplex operation. In half-duplex mode, the Ethernet  
controller supports operation as specified in IEEE 802.3z specification. In the receive path, the  
Ethernet controller supports carrier extended packets and packets generated during packet bursting  
operation. The 82554GC/EI, in the transmit path, also supports carrier extended packets and can  
be configured to transmit in packet burst mode.  
The Ethernet controller offers various filtering capabilities that provide better performance and  
lower processor utilization as follows:  
• Provides up to 16 addresses for exact match unicast/multicast address filtering.  
• Provides multicast address filtering based on 4096 bit vectors. Promiscuous unicast and  
promiscuous multicast filtering are supported as well.  
• The Ethernet controller strips IEEE 802.1q VLAN tag and filter packets based on their VLAN  
1
ID. Up to 4096 VLAN tags are supported .  
In the transmit path, the Ethernet controller supports insertion of VLAN tag information, on a  
packet-by-packet basis.  
The Ethernet controller implements the flow control function as defined in IEEE 802.3x, as well as  
specific operation of asymmetrical flow control as defined by IEEE 802.3z. The Ethernet controller  
also provides external pins for controlling the flow control function through external logic.  
2.3.5  
MII/GMII/TBI/Internal SerDes Interface Block  
The Ethernet controller provides the following serial interfaces:  
• A GMII/MII interface to the internal PHY.  
2
2
• Internal SerDes interface (82546GB/EB and 82545GM/EM)/Ten Bit Interface (TBI) for the  
82544GC/EI: The Ethernet controller implements the 802.3z PCS function, the Auto-  
Negotiation function and 10-bit data path interface (TBI) for both receive and transmit  
operations. It is used for 1000BASE-SX, -LX, and -CX configurations, operating only at 1000  
Mb/s full-duplex. The on-chip PCS circuitry is only used when the link interface is configured  
for TBI mode and it is bypassed in internal PHY modes.  
1. Not applicable to the 82541ER.  
2. Not applicable to the 82544GC/EI, 82540EP/EM, 82541xx, and 82547GI/EI.  
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Architectural Overview  
Note: Refer to the Extended Device Control Register (bits 23:22) for mode selection (see Section 13.4.6).  
The link can be configured by several methods. Software can force the link setting to Auto-  
Negotiation by setting either the MAC in TBI mode (internal SerDes for the 82546GB/EB and  
82545GM/EM), or the PHY in internal PHY mode.  
The speed of the link in internal PHY mode can be determined by several methods:  
• Auto speed detection based on the receive clock signal generated by the PHY.  
• Detection of the PHY link speed indication.  
• Software forcing the configuration of link speed.  
2.3.6  
10/100/1000 Ethernet Transceiver (PHY)  
The Ethernet controller provides a full high-performance, integrated transceiver for 10/100/  
1000 Mb/s data communication. The physical layer (PHY) blocks are 802.3 compliant and capable  
of operating in half-duplex or full-duplex modes.  
Highlights of the PHY blocks are as follows:  
• Data stream serializers and encoders. Encoding techniques include Manchester, 4B/5B and  
4D/PAM5. These blocks also perform data scrambling for 100/1000 Mb/s transmission as a  
technique to minimize radiated Electromagnetic Interference (EMI).  
• A multi-mode transmit digital to analog converter, which produces filtered waveforms  
appropriate for the 10BASE-T, 100BASE-TX or 1000BASE-T Ethernet standards.  
• Receiver Analog-to-Digital Converter (ADC). The ADC uses a 125 MHz sampling rate.  
• Receiver decoders. These blocks perform the inverse operations of serializers, encoders and  
scramblers.  
• Active hybrid and echo canceller blocks. The active hybrid and echo canceller blocks reduce  
the echo effect of transmitting and receiving simultaneously on the same analog pairs.  
• NEXT canceller. This unit removes high frequency Near End Crosstalk induced among  
adjacent signal pairs.  
• Additional wave shaping and slew rate control circuitry to reduce EMI.  
Because the Ethernet controller is IEEE-compliant, the PHY blocks communicate with the MAC  
blocks through an internal GMII/MII bus operating at clock speeds of 2.5 MHz up to 125 MHz.  
The Ethernet controller also uses an IEEE-compliant internal Management Data interface to  
communicate control and status information to the PHY.  
2.3.7  
EEPROM Interface  
The PCI/PCI-X Family of Gigabit Ethernet Controllers provide a four-wire direct interface to a  
serial EEPROM device such as the 93C46 or compatible for storing product configuration  
information. Several words of the data stored in the EEPROM are automatically accessed by the  
Ethernet controller, after reset, to provide pre-boot configuration data to the Ethernet controller  
before it is accessible by the host software. The remainder of the stored information is accessed by  
various software modules to report product configuration, serial number and other parameters.  
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Architectural Overview  
2.3.8  
FLASH Memory Interface  
The Ethernet controller provides an external parallel interface to a FLASH device. Accesses to the  
FLASH are controlled by the Ethernet controller and are accessible to software as normal PCI  
reads or writes to the FLASH memory mapping area. The Ethernet controller supports FLASH  
devices with up to 512 KB of memory.  
Note: The 82540EP/EM provides an external interface to a serial FLASH or Boot EEPROM device. See  
Appendix B for more information.  
2.4  
DMA Addressing  
In appropriate systems, all addresses mastered by the Ethernet controller are 64 bits in order to  
support systems that have larger than 32-bit physical addressing. Providing 64-bit addresses  
eliminates the need for special segment registers.  
Note: The PCI 2.2 or 2.3 Specification requires that any 64-bit address whose upper 32 bits are all 0b  
appear as a 32-bit address cycle. The Ethernet controller complies with the PCI 2.2 or 2.3  
Specification.  
PCI is little-endian; however, not all processors in systems using PCI treat memory as little-endian.  
Network data is fundamentally a byte stream. As a result, it is important that the processor and  
Ethernet controller agree about the representation of memory data. The default is little-endian  
mode.  
Descriptor accesses are not byte swapped.  
The following example illustrates data-byte ordering for little endian. Bytes for a receive packet  
arrive in the order shown from left to right.  
01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e  
Example 2-1. Byte Ordering  
There are no alignment restrictions on packet-buffer addresses. The byte address for the major  
words is shown on the left. The byte numbers and bit numbers for the PCI bus are shown across the  
top.  
Table 2-1. Little Endian Data Ordering  
63  
0
7
6
5
4
3
2
1
0
0
8
08  
10  
18  
20  
07  
0f  
06  
0e  
16  
1e  
05  
0d  
15  
1d  
04  
0c  
14  
1c  
03  
0b  
13  
1b  
02  
0a  
12  
1a  
01  
09  
11  
19  
Byte  
Address  
10  
18  
17  
1f  
14  
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2.5  
Ethernet Addressing  
Several registers store Ethernet addresses in the Ethernet controller. Two 32-bit registers make up  
the address: one is called “high”, and the other is called “low”. For example, the Receive Address  
Register is comprised of Receive Address High (RAH) and Receive Address Low (RAL). The least  
significant bit of the least significant byte of the address stored in the register (for example, bit 0 of  
RAL) is the multicast bit. The LS byte is the first byte to appear on the wire. This notation applies  
to all address registers, including the flow control registers.  
Figure 2-5 shows the bit/byte addressing order comparison between what is on the wire and the  
values in the unique receive address registers.  
Preamble & SFD  
Destination Address  
Source Address  
...XXX  
...55  
D5  
00  
AA  
00  
11  
22  
33  
Bit 0 of this byte is first on the wire  
dest_addr[0]  
33  
22  
22  
11  
11  
00  
00  
AA  
AA  
00  
00  
Destination address stored  
internally as shown here  
Multicast bit  
...  
33  
Figure 2-5. Example of Address Byte Ordering  
The address byte order numbering shown in Figure 2-5 maps to Table 2-2. Byte #1 is first on the  
wire.  
Table 2-2. Intel® Architecture Byte Ordering  
IA Byte #  
1 (LSB)  
2
3
4
5
6 (MSB)  
Byte Value (Hex)  
00  
AA  
00  
11  
22  
33  
Note: The notation in this manual follows the convention shown in Table 2-2. For example, the address in  
Table 2-2 indicates 00_AA_00_11_22_33h, where the first byte (00h_) is the first byte on the wire,  
with bit 0 of that byte transmitted first.  
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2.6  
Interrupts  
The Ethernet controller provides a complete set of interrupts that allow for efficient software  
management. The interrupt structure is designed to accomplish the following:  
• Make accesses “thread-safe” by using ‘set’ and ‘clear-on-read’ rather than ‘read-modify-write’  
operations.  
• Minimize the number of interrupts needed relative to work accomplished.  
• Minimize the processing overhead associated with each interrupt.  
Intel accomplished the first goal by an interrupt logic consisting of four interrupt registers. More  
detail about these registers is given in sections 13.4.17 through 13.4.21.  
• Interrupt Cause ‘Set’ and ‘Read’ Registers  
The Read register records the cause of the interrupt. All bits set at the time of the read are auto-  
cleared. The cause bit is set for each bit written as a 1b in the Set register. If there is a race  
between hardware setting a cause and software clearing an interrupt, the bit remains set. No  
race condition exists on writing the Set register. A ‘set’ provides for software posting of an  
interrupt. A ‘read’ is auto-cleared to avoid expensive write operations. Most systems have  
write buffering, which minimizes overhead, but typically requires a read operation to  
guarantee that the write operation has been flushed from the posted buffers. Without auto-  
clear, the cost of clearing an interrupt can be as high as two reads and one write.  
• Interrupt Mask ‘Set’ (Read) and ‘Clear’ Registers  
Interrupts appear on PCI only if the interrupt cause bit is a 1b, and the corresponding interrupt  
mask bit is a 1b. Software can block assertion of the interrupt wire by clearing the bit in the  
mask register. The cause bit stores the interrupt event regardless of the state of the mask bit.  
The Clear and Set operations make this register more “thread-safe” by avoiding a ‘read-  
modify-write’ operation on the mask register. The mask bit is set to a 1b for each bit written in  
the Set register, and cleared for each bit written in the Clear register. Reading the Set register  
returns the current value.  
Intel accomplished the second goal (minimizing interrupts) by three actions:  
• Reducing the frequency of all interrupts (see Section 13.4.17). Not applicable to the  
82544GC/EI.  
• Accepting multiple receive packets before signaling an interrupt (see Section 3.2.3)  
• Eliminating (or at least reducing) the need for interrupts on transmit (see Section 3.2.7)  
The third goal is accomplished by having one interrupt register consolidate all interrupt  
information. This eliminates the need for multiple accesses.  
Note that the Ethernet controller also supports Message Signaled Interrupts as defined in the PCI  
2.2, 2.3, and PCI-X specifications. See Section 4.1.3.1 for details.  
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Architectural Overview  
2.7  
Hardware Acceleration Capability  
The Ethernet controller provides the ability to offload IP, TCP, and UDP checksum for transmit.  
The functionality provided by these features can significantly reduce processor utilization by  
shifting the burden of the functions from the driver to the hardware.  
The checksum offloading feature is briefly outlined in the following sections. More detail about all  
of the hardware acceleration capabilities is provided in Section 3.2.9.  
2.7.1  
Checksum Offloading  
The Ethernet controller provides the ability to offload the IP, TCP, and UDP checksum require-  
ments from the software device driver. For common frame types, the hardware automatically  
calculates, inserts, and checks the appropriate checksum values normally handled by software.  
For transmits, every Ethernet packet might have two checksums calculated and inserted by the  
Ethernet controller. Typically, these would be the IP checksum, and either the TCP or UDP  
checksum. The software device driver specifies which portions of the packet are included in the  
checksum calculations, and where the calculated values are inserted via descriptors (refer to  
Section 3.3.5 for details).  
For receives, the hardware recognizes the packet type and performs the checksum calculations and  
error checking automatically. Checksum and error information is provided to software through the  
receive descriptors (refer to Section 3.2.9 for details).  
2.7.2  
TCP Segmentation  
The Ethernet controller implements a TCP segmentation capability for transmits that allows the  
software device driver to offload packet segmentation and encapsulation to the hardware. The  
software device driver can send the Ethernet controller the entire IP, TCP or UDP message sent  
down by the Network Operating System (NOS) for transmission. The Ethernet controller segments  
the packet into legal Ethernet frames and transmit them on the wire. By handling the segmentation  
tasks, the hardware alleviates the software from handling some of the framing responsibilities. This  
reduces the overhead on the CPU for the transmission process thus reducing overall CPU  
utilization. See Section 3.5 for details.  
2.8  
Buffer and Descriptor Structure  
Software allocates the transmit and receive buffers, and also forms the descriptors that contain  
pointers to, and the status of, those buffers. A conceptual ownership boundary exists between the  
driver software and the hardware of the buffers and descriptors. The software gives the hardware  
ownership of a queue of buffers for receives. These receive buffers store data that the software then  
owns once a valid packet arrives.  
For transmits, the software maintains a queue of buffers. The driver software owns a buffer until it  
is ready to transmit. The software then commits the buffer to the hardware; the hardware then owns  
the buffer until the data is loaded or transmitted in the transmit FIFO.  
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Descriptors store the following information about the buffers:  
• The physical address  
• The length  
• Status and command information about the referenced buffer  
Descriptors contain an end-of-packet field that indicates the last buffer for a packet. Descriptors  
also contain packet-specific information indicating the type of packet, and specific operations to  
perform in the context of transmitting a packet, such as those for VLAN or checksum offload.  
Section 3 provides detailed information about descriptor structure and operation in the context of  
packet transmission and reception.  
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Receive and Transmit Description 3  
3.1  
Introduction  
This section describes the packet reception, packet transmission, transmit descriptor ring structure,  
TCP segmentation, and transmit checksum offloading for the PCI/PCI-X Family of Gigabit  
Ethernet Controllers.  
Note: The 82544GC/EI does not support IPv6.  
3.2  
Packet Reception  
In the general case, packet reception consists of recognizing the presence of a packet on the wire,  
performing address filtering, storing the packet in the receive data FIFO, transferring the data to a  
receive buffer in host memory, and updating the state of a receive descriptor.  
3.2.1  
Packet Address Filtering  
Hardware stores incoming packets in host memory subject to the following filter modes. If there is  
insufficient space in the receive FIFO, hardware drops them and indicates the missed packet in the  
appropriate statistics registers.  
The following filter modes are supported:  
• Exact Unicast/Multicast — The destination address must exactly match one of 16 stored  
addresses. These addresses can be unicast or multicast.  
• Promiscuous Unicast — Receive all unicasts.  
• Multicast — The upper bits of the incoming packet’s destination address index a bit vector  
that indicates whether to accept the packet; if the bit in the vector is one, accept the packet,  
otherwise, reject it. The controller provides a 4096 bit vector. Software provides four choices  
of which bits are used for indexing. These are [47:36], [46:35], [45:34], or [43:32] of the  
internally stored representation of the destination address.  
• Promiscuous Multicast — Receive all multicast packets.  
• VLAN — Receive all VLAN1 packets that are for this station and have the appropriate bit set  
in the VLAN filter table. A detailed discussion and explanation of VLAN packet filtering is  
contained in Section 9.3.  
Normally, only good packets are received. These are defined as those packets with no CRC error,  
symbol error, sequence error, length error, alignment error, or where carrier extension or receive  
errors are detected. However, if the store–bad–packet bit is set in the Device Control register  
(RCTL.SBP), then bad packets that pass the filter function are stored in host memory. Packet errors  
are indicated by error bits in the receive descriptor (RDESC.ERRORS). It is possible to receive all  
packets, regardless of whether they are bad, by setting the promiscuous enables (RCTL.UPE/MPE)  
and the store–bad–packet bit (RCTL.SBP).  
1. Not applicable to the 82541ER.  
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Receive and Transmit Description  
If manageability is enabled and if RCMCP is enabled then ARP request packets can be directed  
over the SMBus or processed internally by the ASF controller rather than delivered to host memory  
(not applicable to the 82544GC/EI or 82541ER.  
3.2.2  
Receive Data Storage  
Memory buffers pointed to by descriptors store packet data. Hardware supports seven receive  
buffer sizes:  
• 256 B  
• 512 B  
• 1024 B  
• 2048 B  
• 4096 B  
• 8192 B  
• 16384 B  
Buffer size is selected by bit settings in the Receive Control register (RCTL.BSIZE &  
RCTL.BSEX). See Section 13.4.22 for details.  
The Ethernet controller places no alignment restrictions on packet buffer addresses. This is  
desirable in situations where the receive buffer was allocated by higher layers in the networking  
software stack, as these higher layers may have no knowledge of a specific Ethernet controller’s  
buffer alignment requirements.  
Although alignment is completely unrestricted, it is highly recommended that software allocate  
receive buffers on at least cache-line boundaries whenever possible.  
3.2.3  
Receive Descriptor Format  
A receive descriptor is a data structure that contains the receive data buffer address and fields for  
hardware to store packet information. Table 3-1 lists where the shaded areas indicate fields that are  
modified by hardware upon packet reception.  
Table 3-1. Receive Descriptor (RDESC) Layout  
63  
48 47  
40 39  
32 31  
16 15  
0
0
8
Buffer Address [63:0]  
Packet Checksum  
(See Note)  
Special  
Errors  
Status  
Length  
82544GC/EI only  
63  
48 47  
40 39  
Buffer Address [63:0]  
Status Reserved  
32 31  
16 15  
0
0
8
Reserved  
Errors  
Length  
Note: The checksum indicated here is the unadjusted “16 bit ones complement” of the packet. A software  
assist may be required to back out appropriate information prior to sending it to upper software  
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Receive and Transmit Description  
layers. The packet checksum is always reported in the first descriptor (even in the case of multi-  
descriptor packets).  
Upon receipt of a packet for Ethernet controllers, hardware stores the packet data into the indicated  
buffer and writes the length, Packet Checksum, status, errors, and status fields. Length covers the  
data written to a receive buffer including CRC bytes (if any). Software must read multiple  
descriptors to determine the complete length for packets that span multiple receive buffers.  
For standard 802.3 packets (non-VLAN) the Packet Checksum is by default computed over the  
entire packet from the first byte of the DA through the last byte of the CRC, including the Ethernet  
and IP headers. Software may modify the starting offset for the packet checksum calculation by  
means of the Receive Control Register. This register is described in Section 13.4.22. To verify the  
TCP checksum using the Packet Checksum, software must adjust the Packet Checksum value to  
back out the bytes that are not part of the true TCP Checksum.  
3.2.3.1  
Receive Descriptor Status Field  
Status information indicates whether the descriptor has been used and whether the referenced  
buffer is the last one for the packet. Refer to Table 3-2 for the layout of the status field. Error status  
information is shown in Table 3-3.  
For multi-descriptor packets, packet status is provided in the final descriptor of the packet (EOP  
set). If EOP is not set for a descriptor, only the Address, Length, and DD bits are valid.  
Table 3-2. Receive Status (RDESC.STATUS) Layout  
7
6
5
4
3
2
1
0
PIF  
IPCS  
TCPCS  
RSV  
VP  
IXSM  
EOP  
DD  
Receive  
Descriptor Status  
Bits  
Description  
Passed in-exact filter  
Hardware supplies the PIF field to expedite software processing of packets.  
Software must examine any packet with PIF set to determine whether to accept  
the packet. If PIF is clear, then the packet is known to be for this station, so  
software need not look at the packet contents. Packets passing only the  
Multicast Vector has PIF set.  
PIF (bit 7)  
IP Checksum Calculated on Packet  
When Ignore Checksum Indication is deasserted (IXSM = 0b), IPCS bit indicates  
whether the hardware performed the IP checksum on the received packet.  
0b = Do not perform IP checksum  
1b = Perform IP checksum  
IPCS (bit 6)  
Pass/Fail information regarding the checksum is indicated in the error bit (IPE) of  
the descriptor receive errors (RDESC.ERRORS)  
IPv6 packets do not have the IPCS bit set.  
Reads as 0b.  
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Receive and Transmit Description  
Receive  
Descriptor Status  
Bits  
Description  
TCP Checksum Calculated on Packet  
When Ignore Checksum Indication is deasserted (IXSM = 0b), TCPCS bit  
indicates whether the hardware performed the TCP/UDP checksum on the  
received packet.  
0b = Do not perform TCP/UDP checksum; 1b = Perform TCP/UDP checksum  
TCPCS (bit 5)  
Pass/Fail information regarding the checksum is indicated in the error bit (TCPE)  
of the descriptor receive errors (RDESC.ERRORS).  
IPv6 packets may have this bit set if the TCP/UDP packet was recognized.  
Reads as 0b.  
Reserved  
RSV (bit 4)  
VP (bit 3)  
Reads as 0b.  
Packet is 802.1Q (matched VET)  
Indicates whether the incoming packet’s type matches VET (i.e., if the packet is  
a VLAN (802.1q) type). It is set if the packet type matches VET and CTRL.VME  
is set. For a further description of 802.1q VLANs, see Chapter 9.  
Reads as 0b.  
Ignore Checksum Indication  
When IXSM = 1b, the checksum indication results (IPCS, TCPCS bits) should be  
ignored.  
When IXSM = 0b the IPCS and TCPCS bits indicate whether the hardware  
performed the IP or TCP/UDP checksum(s) on the received packet. Pass/Fail  
information regarding the checksum is indicated in the status bits as described  
below for IPE and TCPE.  
IXSM (bit 2)  
Reads as 1b.  
End of Packet  
EOP (bit 1)  
DD (bit 0)  
EOP indicates whether this is the last descriptor for an incoming packet.  
Descriptor Done  
Indicates whether hardware is done with the descriptor. When set along with  
EOP, the received packet is complete in main memory.  
Note: See Table 3-5 for a description of supported packet types for receive checksum offloading.  
Unsupported packet types either have the IXSM bit set, or they don’t have the TCPCS bit set.  
3.2.3.2  
Receive Descriptor Errors Field  
Most error information appears only when the Store Bad Packets bit (RCTL.SBP) is set and a bad  
packet is received. Refer to Table 3-3 for a definition of the possible errors and their bit positions.  
The error bits are valid only when the EOP and DD bits are set in the descriptor status field  
(RDESC.STATUS)  
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Receive and Transmit Description  
Table 3-3. Receive Errors (RDESC.ERRORS) Layout  
7
6
5
4
3
2
1
0
RSV  
CXEa  
SEQ  
SE  
RXE  
IPE  
TCPE  
RSV  
CE  
RSVb RSVb  
a. 82544GC/EI only.  
b. 82541xx, 82547GI/EI, and 82540EP/EM only.  
Receive  
Descriptor Error  
bits  
Description  
RX Data Error  
Indicates that a data error occurred during the packet reception. A data error in TBIa  
mode (82544GC/EI)/internal SerDes (82546GB/EB and 82545GM/EM) refers to the  
reception of a /V/ code (see Section 8.2.1.3). In GMII or MII mode, the assertion of  
I_RX_ER during data reception indicates a data error. This bit is valid only when the  
EOP and DD bits are set; it is not set in descriptors unless RCTL.SBP (Store Bad  
Packets) control bit is set.  
RXE (bit 7)  
IP Checksum Error  
When set, indicates that IP checksum error is detected in the received packet. Valid  
only when the IP checksum is performed on the receive packet as indicated via the  
IPCS bit in the RDESC.STATUS field.  
IPE (bit 6)  
If receive IP checksum offloading is disabled (RXCSUM.IPOFL), the IPE bit is set to  
0b. It has no effect on the packet filtering mechanism.  
Reads as 0b.  
TCP/UDP Checksum Error  
When set, indicates that TCP/UDP checksum error is detected in the received  
packet.  
Valid only when the TCP/UDP checksum is performed on the receive packet as  
indicated via TCPCS bit in RDESC.STATUS field.  
TCPE (bit 5)  
If receive TCP/UDP checksum offloading is disabled (RXCSUM.TUOFL), the TCPE  
bit is set to 0b.  
It has no effect on the packet filtering mechanism.  
Reads as 0b.  
Carrier Extension Error  
When set, indicates a packet was received in which the carrier extension error was  
signaled across the GMII interface. A carrier extension error is signaled by the PHY  
by the encoding of 1Fh on the receive data inputs while I_RX_ER is asserted.  
CXE  
RSV (bit 4)  
Valid only while working in 1000 Mb/s half-duplex mode of operation.  
This bit is reserved for all Ethernet controllers except the 82544GC/EI.  
Reserved  
RSV (Bit 3)  
Reads as 0b.  
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Receive and Transmit Description  
Receive  
Descriptor Error  
bits  
Description  
Sequence Error  
When set, indicates a received packet with a bad delimiter sequence (in TBI mode/  
internal SerDes). In other 802.3 implementations, this would be classified as a  
framing error.  
SEQ (bit 2)  
A valid delimiter sequence consists of:  
idle start-of-frame (SOF) data, pad (optional) end-of-frame (EOF) fill  
(optional) idle.  
Symbol Error  
SE (bit 1)  
CE (bit 0)  
When set, indicates a packet received with bad symbol. Applicable only in TBI mode/  
internal SerDes.  
CRC Error or Alignment Error  
CRC errors and alignment errors are both indicated via the CE bit. Software may  
distinguish between these errors by monitoring the respective statistics registers.  
a. Not applicable to the 82540EP/EM, 82541xx, or 82547GI/EI.  
3.2.3.3  
Receive Descriptor Special Field  
Hardware stores additional information in the receive descriptor for 802.1q packets. If the packet  
type is 802.1q, determined when a packet type field matches the VLAN1 Ethernet Register (VET)  
and RCTL.VME = 1b, then the special field records the VLAN information and the four byte  
VLAN information is stripped from the packet data storage. The Ethernet controller stores the Tag  
Control Information (TCI) of the 802.1q tag in the Special field. Otherwise, the special field  
contains 0000h.  
Table 3-4. Special Descriptor Field Layout  
802.1q Packets  
15  
13  
12  
11  
0
PRI  
CFI  
VLAN  
All Other Packets  
15  
8 7  
0
00  
00  
Receive  
Descriptor  
Special Field  
Description  
VLAN Identifier  
VLAN  
CFI  
12 bits that records the packet VLAN ID number  
Canonical Form Indicator  
1 bit that records the packet’s CFI VLAN field  
User Priority  
PRI  
3 bits that records the packet’s user priority field.  
1. Not applicable to the 82541ER.  
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Receive and Transmit Description  
3.2.4  
Receive Descriptor Fetching  
The descriptor fetching strategy is designed to support large bursts across the PCI bus. This is made  
possible by using 64 on-chip receive descriptors and an optimized fetching algorithm. The fetching  
algorithm attempts to make the best use of PCI bandwidth by fetching a cache line (or more)  
descriptors with each burst. The following paragraphs briefly describe the descriptor fetch  
algorithm and the software control provided.  
When the on-chip buffer is empty, a fetch happens as soon as any descriptors are made available  
(software writes to the tail pointer). When the on-chip buffer is nearly empty  
(RXDCTL.PTHRESH), a prefetch is performed whenever enough valid descriptors  
(RXDCTL.HTHRESH) are available in host memory and no other PCI activity of greater priority  
is pending (descriptor fetches and write-backs or packet data transfers).  
When the number of descriptors in host memory is greater than the available on-chip descriptor  
storage, the chip may elect to perform a fetch which is not a multiple of cache line size. The  
hardware performs this non-aligned fetch if doing so results in the next descriptor fetch being  
aligned on a cache line boundary. This mechanism provides the highest efficiency in cases where  
fetches fall behind software.  
Note: The Ethernet controller never fetches descriptors beyond the descriptor TAIL pointer.  
No  
No  
On-chip  
descriptor cache  
is empty  
Yes  
No  
On-chip  
Yes  
descriptor cache  
<
RDXCTL.PTHRESH  
Valid descriptors  
in host memory >  
RXDCTL.HTHRESH  
Descriptors  
are available in  
host memory  
Yes  
Yes  
Pre-fetch (based  
on PCI priority)  
Fetch  
Figure 3-1. Receive Descriptor Fetching Algorithm  
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Receive and Transmit Description  
3.2.5  
Receive Descriptor Write-Back  
Processors have cache line sizes that are larger than the receive descriptor size (16 bytes).  
Consequently, writing back descriptor information for each received packet would cause expensive  
partial cache line updates. Two mechanisms minimize the occurrence of partial line write backs:  
• Receive descriptor packing  
• Null descriptor padding  
The following sections explain these mechanisms.  
3.2.5.1  
Receive Descriptor Packing  
To maximize memory efficiency, receive descriptors are “packed” together and written as a cache  
line whenever possible. Descriptors accumulate and are written out in one of three conditions:  
• RXDCTL.WTHRESH descriptors have been used (the specified max threshold of unwritten  
used descriptors has been reached)  
• The receive timer expires (RADV or RDTR)  
• Explicit software flush (RDTR.FPD)  
For the first condition, if the number of descriptors specified by RXDCTL.WTHRESH are used,  
they are written back, regardless of cacheline alignment. It is therefore recommended that  
WTHRESH be a multiple of cacheline sizes.  
In the second condition, a timer (RDTR or RADV) expiration causes all used descriptors to be  
written back prior to initiating an interrupt.  
In the second condition for the 82544GC/EI, a timer (RDTR) is included to force timely write–  
back of descriptors. The first packet after timer initialization starts the timer. Timer expiration  
flushes any accumulated descriptors and sets an interrupt event (receiver timer interrupt). In  
general, the arrival rate is sufficiently fast enough that packing is the common case under load.  
For the final condition, software may explicitly flush accumulated descriptors by writing the timer  
register with the high order bit set.  
3.2.5.2  
3.2.6  
Null Descriptor Padding  
Hardware stores no data in descriptors with a null data address. Software can make use of this  
property to cause the first condition under receive descriptor packing to occur early. Hardware  
writes back null descriptors with the DD bit set in the status byte and all other bits unchanged.  
Receive Descriptor Queue Structure  
Figure 3-2 shows the structure of the receive descriptor ring. Hardware maintains a circular ring of  
descriptors and writes back used descriptors just prior to advancing the head pointer. Head and tail  
pointers wrap back to base when “size” descriptors have been processed.  
Software adds receive descriptors by writing the tail pointer with the index of the entry beyond the  
last valid descriptor. As packets arrive, they are stored in memory and the head pointer is  
incremented by hardware. When the head pointer is equal to the tail pointer, the ring is empty.  
Hardware stops storing packets in system memory until software advances the tail pointer, making  
more receive buffers available.  
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Receive and Transmit Description  
The receive descriptor head and tail pointers reference 16-byte blocks of memory. Shaded boxes in  
the figure represent descriptors that have stored incoming packets but have not yet been recognized  
by software. Software can determine if a receive buffer is valid by reading descriptors in memory  
rather than by I/O reads. Any descriptor with a non-zero status byte has been processed by the  
hardware, and is ready to be handled by the software.  
Circular Buffer Queues  
Base  
Head  
Owned By  
Hardware  
Receive  
Queue  
Tail  
Base + Size  
Figure 3-2. Receive Descriptor Ring Structure  
Note: The head pointer points to the next descriptor that is written back. At the completion of the  
descriptor write-back operation, this pointer is incremented by the number of descriptors written  
back. HARDWARE OWNS ALL DESCRIPTORS BETWEEN [HEAD AND TAIL]. Any  
descriptor not in this range is owned by software.  
The receive descriptor ring is described by the following registers:  
• Receive Descriptor Base Address registers (RDBAL and RDBAH)  
These registers indicate the start of the descriptor ring buffer. This 64-bit address is aligned on  
a 16-byte boundary and is stored in two consecutive 32-bit registers. RDBAL contains the  
lower 32-bits; RDBAH contains the upper 32 bits. Hardware ignores the lower 4 bits in  
RDBAL.  
• Receive Descriptor Length register (RDLEN)  
This register determines the number of bytes allocated to the circular buffer. This value must  
be a multiple of 128 (the maximum cache line size). Since each descriptor is 16 bytes in  
length, the total number of receive descriptors is always a multiple of 8.  
• Receive Descriptor Head register (RDH)  
This register holds a value that is an offset from the base, and indicates the in–progress  
descriptor. There can be up to 64K descriptors in the circular buffer. Hardware maintains a  
shadow copy that includes those descriptors completed but not yet stored in memory.  
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Receive and Transmit Description  
• Receive Descriptor Tail register (RDT)  
This register holds a value that is an offset from the base, and identifies the location beyond the  
last descriptor hardware can process. Note that tail should still point to an area in the descriptor  
ring (somewhere between RDBA and RDBA + RDLEN). This is because tail points to the  
location where software writes the first new descriptor.  
If software statically allocates buffers, and uses memory read to check for completed descriptors, it  
simply has to zero the status byte in the descriptor to make it ready for reuse by hardware. This is  
not a hardware requirement (moving the hardware tail pointer is), but is necessary for performing  
an in–memory scan.  
3.2.7  
Receive Interrupts  
The Ethernet controller can generate four receive-related interrupts:  
• Receiver Timer Interrupt (ICR.RXT0)  
• Small Receive Packet Detect (ICR.SRPD)  
• Receive Descriptor Minimum Threshold (ICR.RXDMT0)  
• Receiver FIFO Overrun (ICR.RX0)  
3.2.7.1  
Receive Timer Interrupt  
The Receive Timer Interrupt is used to signal most packet reception events (the Small Receive  
Packet Detect interrupt is also used in some cases as described later in this section). In order to  
minimize the interrupts per work accomplished, the Ethernet controller provides two timers to  
control how often interrupts are generated.  
3.2.7.1.1 Receive Interrupt Delay Timer / Packet Timer (RDTR)  
The Packet Timer minimizes the number of interrupts generated when many packets are received  
in a short period of time. The packet timer is started once a packet is received and transferred to  
host memory (specifically, after the last packet data byte is written to memory) and is reinitialized  
(to the value defined in RDTR) and started EACH TIME a new packet is received and transferred  
to the host memory. When the Packet Timer expires (e.g. no new packets have been received and  
transferred to host memory for the amount of time defined in RDTR) the Receive Timer Interrupt is  
generated.  
Setting the Packet Timer to 0b disables both the Packet Timer and the Absolute Timer (described  
below) and causes the Receive Timer Interrupt to be generated whenever a new packet has been  
stored in memory.  
Writing to RDTR with its high order bit (FPD) set forces an explicit writeback of consumed  
descriptors (potentially a partial cache lines amount of descriptors), causes an immediate expiration  
of the Packet Timer and generates a Receive Timer Interrupt.  
The Packet Timer is reinitialized (but not started) when the Receive Timer Interrupt is generated  
due to an Absolute timer expiration or Small Receive Packet Detect Interrupt.  
See section Section 13.4.30 for more details on the Packet Timer.  
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Receive and Transmit Description  
Initial State  
Packet received &  
transferred to host  
memory  
Idle  
Restart Count  
Other receive  
timer interrupt  
Restart Count  
Running  
Packet received &  
transferred to host  
memory  
Generate  
Int  
Timer expires  
Figure 3-3. Packet Delay Timer Operation (State Diagram)  
3.2.7.1.2 Receive Interrupt Absolute Delay Timer (RADV)  
The Absolute Timer ensures that a receive interrupt is generated at some predefined interval after  
the first packet is received. The absolute timer is started once a packet is received and transferred to  
host memory (specifically, after the last packet data byte is written to memory) but is NOT  
reinitialized / restarted each time a new packet is received. When the Absolute Timer expires (no  
receive interrupt has been generated for the amount of time defined in RADV) the Receive Timer  
Interrupt is generated.  
Setting RADV to 0b or RDTR to 0b disables the Absolute Timer. To disable the Packet Timer only,  
RDTR should be set to RADV + 1b.  
The Absolute Timer is reinitialized (but not started) when the Receive Timer Interrupt is generated  
due to a Packet Timer expiration or Small Receive Packet Detect Interrupt.  
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Receive and Transmit Description  
The diagrams below show how the Packet Timer and Absolute Timer can be used together:  
Case A: Using only an absolute timer  
A bsolute Timer Value  
Interrupt generated due to PKT #1  
PKT #1  
PKT #2  
PKT #3  
PKT #4  
Case B: Using an absolute time in conjunction with the Packet timer  
A bsolute Timer Value  
A bsolute Timer Value  
PKT #1  
PKT #2  
PKT #3  
PKT #4  
PKT #5  
PKT #6  
...  
...  
...  
1) Packet timer expires  
2) Interrupt generated  
3) Absolute timer reset  
Interrupt generalted (due to PKT #4)  
as absolute timer expires.  
Packet delay timer disabled untill  
next packet is received and  
transferred to host memory.  
Case C: Packet timer expiring while a packet is transferred to host memory.  
Illustrates that packet timer is re-started only after a packet is transferred to host memory.  
A bsolute Timer Value  
A bsolute Timer Value  
PKT #1  
PKT #2  
PKT #3  
PKT #4  
PKT #5  
PKT #6  
...  
...  
...  
1) Packet timer expires  
2) Interrupt generated  
3) Absolute timer reset  
Interrupt generalted (due to PKT #4)  
as absolute timer expires.  
Packet delay timer disabled untill  
next packet is received and  
transferred to host memory.  
3.2.7.2  
Small Receive Packet Detect  
A Small Receive Packet Detect interrupt (ICR.SRPD) is asserted when small-packet detection is  
enabled (RSRPD is set with a non-zero value) and a packet of (size RSRPD.SIZE) has been  
transferred into the host memory. When comparing the size the headers and CRC are included (if  
CRC stripping is not enabled). CRC and VLAN headers are not included if they have been  
stripped. A receive timer interrupt cause (ICR.RXT0) is also noted when the Small Packet Detect  
interrupt occurs.  
For the 82541xx and 82547GI/EI, receiving a small packet does not clear the absolute or packet  
delay timers, so one packet might generate two interrupts, one due to small packet reception and  
one due to timer expiration.  
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Receive and Transmit Description  
3.2.7.3  
3.2.7.4  
Receive Descriptor Minimum Threshold (ICR.RXDMT)  
The minimum descriptor threshold helps avoid descriptor under-run by generating an interrupt  
when the number of free descriptors becomes equal to the minimum amount defined in  
RCTL.RDMTS (measured as a fraction of the receive descriptor ring size).  
Receiver FIFO Overrun  
FIFO overrun occurs when hardware attempts to write a byte to a full FIFO. An overrun could  
indicate that software has not updated the tail pointer to provide enough descriptors/buffers, or that  
the PCI bus is too slow draining the receive FIFO. Incoming packets that overrun the FIFO are  
dropped and do not affect future packet reception.  
3.2.8  
82544GC/EI Receive Interrupts  
The presence of new packets is indicated by the following:  
• Absolute timer (RDTR) — A predetermined amount of time has elapsed since the first packet  
received after the hardware timer was written (specifically, after the last packet data byte was  
written to memory); this also flushes any accumulated descriptors to memory. Software can set  
the timer value to 0b if it wants to be notified each time a new packet has been stored in  
memory.  
Writing the absolute timer with its high order bit 1 forces an explicit flush of any partial cache  
lines. Hardware writes all used descriptors to memory and updates the globally visible value of  
the head pointer.  
In addition, hardware provides the following interrupts:  
• Receive Descriptor Minimum Threshold (ICR.RXDMT)  
The minimum descriptor threshold helps avoid descriptor underrun by generating an interrupt  
when the number of free descriptors becomes equal to the minimum. It is measured as a  
fraction of the receive descriptor ring size.  
• Receiver FIFO Overrun (ICR.RXO)  
FIFO overrun occurs when hardware attempts to write a byte to a full FIFO. An overrun could  
indicate that software has not updated the tail pointer to provide enough descriptors/buffers, or  
that the PCI bus is too slow draining the receive FIFO. Incoming packets that overrun the  
FIFO are dropped and do not affect future packet reception.  
3.2.9  
Receive Packet Checksum Offloading  
The Ethernet controller supports the offloading of three receive checksum calculations: the Packet  
Checksum, the IP Header Checksum, and the TCP/UDP Checksum.  
Note: IPv6 packets do not have IP checksums.  
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Receive and Transmit Description  
The Packet checksum is the one’s complement over the receive packet, starting from the byte  
indicated by RXCSUM.PCSS (0b corresponds to the first byte of the packet), after stripping. For  
example, for an Ethernet II frame encapsulated as an 802.3ac VLAN packet and with  
RXCSUM.PCSS set to 14 decimal, the Packet Checksum would include the entire encapsulated  
frame, excluding the 14-byte Ethernet header (DA,SA,Type/Length) and the 4-byte q-tag. The  
Packet checksum does not include the Ethernet CRC if the RCTL.SECRC bit is set.  
Software must make the required offsetting computation (to back out the bytes that should not have  
been included and to include the pseudo-header) prior to comparing the Packet Checksum against  
the TCP checksum stored in the packet.  
For supported packet/frame types, the entire checksum calculation may be offloaded to the  
Ethernet controller. If RXCSUM.IPOFLD is set to 1b, the controller calculates the IP checksum  
and indicates a pass/fail condition to software by means of the IP Checksum Error bit  
(RDESC.IPE) in the ERROR field of the receive descriptor. Similarly, if the RXCSUM.TUOFLD  
is set to 1b, the Ethernet controller calculates the TCP or UDP checksum and indicates a pass/fail  
condition to software by means of the TCP/UDP Checksum Error bit (RDESC.TCPE). These error  
bits are valid when the respective status bits indicate the checksum was calculated for the packet  
(RDESC.IPCS and RDESC.TCPCS).  
If neither RXCSUM.IPOFLD nor RXCSUM.TUOFLD is set, the Checksum Error bits (IPE and  
TCPE) is 0b for all packets.  
Supported Frame Types include:  
• Ethernet II  
• Ethernet SNAP  
Note: See Table 3-6 for the 82544GC/EI supported receive checksum capabilities.  
Table 3-5. Supported Receive Checksum Capabilities  
HW IP Checksum  
Calculation  
HW TCP/UDP Checksum  
Calculation  
Packet Type  
IPv4 packets  
IPv6 packets  
Yes  
Yes  
Yes  
No (n/a)  
IPv6 packet with next header options:  
Hop-by-Hop options  
Destinations options  
Routing  
No (n/a)  
No (n/a)  
No (n/a)  
No (n/a)  
Yes  
Yes  
Yes  
No  
Fragment  
IPv4 tunnels:  
IPv4 packet in an IPv4 tunnel  
IPv6 packet in an IPv4 tunnel  
No  
No  
Yesa  
Yes (IPv4)  
IPv6 tunnels:  
IPv4 packet in an IPv6 tunnel  
IPv6 packet in an IPv6 tunnel  
No  
No  
No  
No  
Packet is an IPv4 fragment  
Yes  
Yes  
Yes  
No  
Packet is greater than 1552 bytes;  
(LPE=1b)b  
Yes  
Yes  
Packet has 802.3ac tag  
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Receive and Transmit Description  
Table 3-5. Supported Receive Checksum Capabilities  
HW IP Checksum  
Calculation  
HW TCP/UDP Checksum  
Calculation  
Packet Type  
IPv4 Packet has IP options  
Yes  
Yes  
Yes  
Yes  
Yes  
No  
(IP header is longer than 20 bytes)  
Packet has TCP or UDP options  
IP header’s protocol field contains a  
protocol # other than TCP or UDP.  
a. The IPv6 header portion can include supported extension headers as described in the IPv6 Filter  
section.  
b.For the 82541xx and 82547GI/EI, frame sizes greater than 2 KB require full-duplex operation.  
Table 3-6. 82544GC/EI Supported Receive Checksum Capabilities  
HW IP Checksum  
Calculation  
HW TCP/UDP  
Checksum Calculation  
Packet Type  
IP v4 packets  
IP v6 packets  
Yes  
No  
Yes  
No  
(no IP checksum in IPv6)  
Packet is an IP fragment  
Yes  
Yes  
Yes  
No  
Yes  
Yes  
Packet is greater than 1552 bytes; (LPE=1)  
Packet has 802.3ac tag  
Packet has IP options  
Yes  
Yes  
Yes  
Yes  
Yes  
No  
(IP header is longer than 20 bytes)  
Packet has TCP or UDP options  
IP header’s protocol field contains a protocol  
other than TCP or UDP.  
Table 3-5 lists the general details about what packets are processed. In more detail, the packets are  
passed through a series of filters (Section 3.2.9.1 through Section 3.2.9.5) to determine if a receive  
checksum is calculated.  
Note: (Section 3.2.9.1 through Section 3.2.9.5) does not apply to the 82544GC/EI.  
3.2.9.1  
MAC Address Filter  
This filter checks the MAC destination address to be sure it is valid (IA match, broadcast,  
multicast, etc.). The receive configuration settings determine which MAC addresses are accepted.  
See the various receive control configuration registers such as RCTL (RTCL.UPE, RCTL.MPE,  
RCTL.BAM), MTA, RAL, and RAH.  
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Receive and Transmit Description  
3.2.9.2  
SNAP/VLAN Filter  
This filter checks the next headers looking for an IP header. It is capable of decoding Ethernet II,  
Ethernet SNAP, and IEEE 802.3ac headers. It skips past any of these intermediate headers and  
looks for the IP header. The receive configuration settings determine which next headers are  
accepted. See the various receive control configuration registers such as RCTL (RCTL.VFE), VET,  
and VFTA.  
3.2.9.3  
3.2.9.4  
IPv4 Filter  
This filter checks for valid IPv4 headers. The version field is checked for a correct value (4). IPv4  
headers are accepted if they are any size greater than or equal to 5 (dwords). If the IPv4 header is  
properly decoded, the IP checksum is checked for validity. The RXCSUM.IPOFL bit must be set  
for this filter to pass.  
IPv6 Filter  
This filter checks for valid IPv6 headers, which are a fixed size and have no checksum. The IPv6  
extension headers accepted are: Hop-by-Hop, Destination Options, and Routing. The maximum  
size next header accepted is 16 dwords (64 bytes).  
All of the IPv6 extension headers supported by the Ethernet controller have the same header  
structure:  
Byte 0  
Byte 1  
Byte 2  
Byte 3  
Next Header  
Hdr Ext Len  
• NEXT HEADER is a value that identifies the header type. The supported IPv6 next headers  
values are:  
— Hop-by-Hop = 00h  
— Destination Options = 3Ch  
— Routing = 2Bh  
• HDR EXT LEN is the 8 byte count of the header length, not including the first 8 bytes. For  
example, a value of 3 means that the total header size including the NEXT HEADER and  
HDR EXT LEN fields is 32 bytes (8 + 3*8).  
— The RXCSUM.IPV6OFL bit must be set for this filter to pass.  
3.2.9.5  
UDP/TCP Filter  
This filter checks for a valid UDP or TCP header. The prototype next header values are 11h and  
06h, respectively. The RXCSUM.TUOFL bit must be set for this filter to pass.  
3.3  
Packet Transmission  
The transmission process for regular (non-TCP Segmentation packets) involves:  
• The protocol stack receives from an application a block of data that is to be transmitted.  
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Receive and Transmit Description  
• The protocol stack calculates the number of packets required to transmit this block based on  
the MTU size of the media and required packet headers.  
• For each packet of the data block:  
— Ethernet, IP and TCP/UDP headers are prepared by the stack.  
— The stack interfaces with the software device driver and commands the driver to send the  
individual packet.  
— The driver gets the frame and interfaces with the hardware.  
— The hardware reads the packet from host memory (via DMA transfers).  
— The driver returns ownership of the packet to the Network Operating System (NOS) when  
the hardware has completed the DMA transfer of the frame (indicated by an interrupt).  
Output packets are made up of pointer–length pairs constituting a descriptor chain (so called  
descriptor based transmission). Software forms transmit packets by assembling the list of pointer–  
length pairs, storing this information in the transmit descriptor, and then updating the on–chip  
transmit tail pointer to the descriptor. The transmit descriptor and buffers are stored in host  
memory. Hardware typically transmits the packet only after it has completely fetched all packet  
data from host memory and deposited it into the on-chip transmit FIFO. This permits TCP or UDP  
checksum computation, and avoids problems with PCI underruns.  
3.3.1  
3.3.2  
Transmit Data Storage  
Data are stored in buffers pointed to by the descriptors. Alignment of data is on an arbitrary byte  
boundary with the maximum size per descriptor limited only to the maximum allowed packet size  
(16288 bytes). A packet typically consists of two (or more) descriptors, one (or more) for the  
header and one for the actual data. Some software implementations copy the header(s) and packet  
data into one buffer and use only one descriptor per transmitted packet.  
Transmit Descriptors  
The Ethernet controller provides three types of transmit descriptor formats.  
The original descriptor is referred to as the “legacy” descriptor format. The two other descriptor  
types are collectively referred to as extended descriptors. One of them is similar to the legacy  
descriptor in that it points to a block of packet data. This descriptor type is called the TCP/IP Data  
Descriptor and is a replacement for the legacy descriptor since it offers access to new offloading  
capabilities. The other descriptor type is fundamentally different as it does not point to packet data.  
It merely contains control information which is loaded into registers of the controller and affect the  
processing of future packets. The following sections describe the three descriptor formats.  
The extended descriptor types are accessed by setting the TDESC.DEXT bit to 1b. If this bit is set,  
the TDESC.DTYP field is examined to control the interpretation of the remaining bits of the  
descriptor. Table 3-7 shows the generic layout for all extended descriptors. Fields marked as NR  
are not reserved for any particular function and are defined on a per-descriptor type basis. Notice  
that the DEXT and DTYP fields are non-contiguous in order to accommodate legacy mode  
operation. For legacy mode operation, bit 29 is set to 0b and the descriptor is defined in Section  
3.3.3.  
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Receive and Transmit Description  
Table 3-7. Transmit Descriptor (TDESC) Layout  
63  
30 29 28  
Buffer Address [63:0]  
DEXT NR  
24 23 20 19  
0
0
8
NR  
DTYP  
NR  
3.3.3  
Legacy Transmit Descriptor Format  
To select legacy mode operation, bit 29 (TDESC.DEXT) should be set to 0b. In this case, the  
descriptor format is defined as shown in Table 3-8. The address and length must be supplied by  
software. Bits in the command byte are optional, as are the Checksum Offset (CSO), and  
Checksum Start (CSS) fields.  
Table 3-8. Transmit Descriptor (TDESC) Layout – Legacy Mode  
63  
48 47  
40 39 36 35 32 31 24 23  
Buffer Address [63:0]  
16 15  
0
0
8
Special  
CSS  
RSV STA CMD  
CSO  
Length  
Table 3-9. Transmit Descriptor Legacy Descriptions  
Transmit Descriptor  
Description  
Legacy  
Buffer Address  
Address of the transmit descriptor in the host memory. Descriptors with a  
null address transfer no data. If they have the RS bit in the command byte  
set (TDESC.CMD), then the DD field in the status word (TDESC.STATUS) is  
written when the hardware processes them.  
Buffer Address  
Length is per segment.  
The maximum length associated with any single legacy descriptor is 16288  
bytes. Although a buffer as short as one byte is allowed, the total length of  
the packet, before padding and CRC insertion must be at least 48 bytes.  
Length can be up to a default value of 16288 bytes per descriptor, and  
16288 bytes total. In other words, the length of the buffer pointed to by one  
descriptor, or the sum of the lengths of the buffers pointed to by the  
descriptors can be as large as the maximum allowed transmit packet.  
Length  
Descriptors with zero length transfer no data. If they have the RS bit in the  
command byte set (TDESC.CMD), then the DD field in the status word  
(TDESC.STATUS) is written when the hardware processes them.  
Checksum Offset  
The Checksum offset field indicates where, relative to the start of the packet,  
to insert a TCP checksum if this mode is enabled. (Insert Checksum bit (IC)  
is set in TDESC.CMD). Hardware ignores CSO unless EOP is set in  
TDESC.CMD. CSO is provided in unit of bytes and must be in the range of  
the data provided to the Ethernet controller in the descriptor. (CSO < length -  
1).  
CSO  
Should be written with 0b for future compatibility.  
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Receive and Transmit Description  
Transmit Descriptor  
Legacy  
Description  
Command field  
CMD  
See Section 3.3.3.1 for a detailed field description.  
Status field  
STA  
See Section 3.3.3.2 for a detailed field description.  
Reserved  
RSV  
Should be written with 0b for future compatibility.  
Checksum Start Field  
The Checksum start field (TDESC.CSS) indicates where to begin computing  
the checksum. The software must compute this offset to back out the bytes  
that should not be included in the TCP checksum. CSS is provided in units  
of bytes and must be in the range of data provided to the Ethernet controller  
in the descriptor (CSS < length). For short packets that ar padded by the  
software, CSS must be in the range of the unpadded data length. A value of  
0b corresponds to the first byte in the packet.  
CSS  
CSS must be set in the first descriptor of the packet.  
Special Field  
Special  
See the notes that follow this table for a detailed field description.  
Notes:  
1. Even though CSO and CSS are in units of bytes, the checksum calculation typically works on  
16-bit words. Hardware does not enforce even byte alignment.  
2. Hardware does not add the 802.1Q EtherType or the VLAN field following the 802.1Q  
EtherType to the checksum. So for VLAN packets, software can compute the values to back  
out only on the encapsulated packet rather than on the added fields.  
3. Although the Ethernet controller can be programmed to calculate and insert TCP checksum  
using the legacy descriptor format as described above, it is recommended that software use the  
newer TCP/IP Context Transmit Descriptor Format. This newer descriptor format allows the  
hardware to calculate both the IP and TCP checksums for outgoing packets. See Section 3.3.5  
for more information about how the new descriptor format can be used to accomplish this task.  
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Receive and Transmit Description  
3.3.3.1  
Transmit Descriptor Command Field Format  
The CMD byte stores the applicable command and has fields shown in Table 3-10.  
Table 3-10. Transmit Command (TDESC.CMD) Layout  
7
6
5
4
3
2
1
0
RSV  
RPSa  
IDE  
VLE  
DEXT  
RS  
IC  
IFCS EOP  
a. 82544GC/EI only.  
TDESC.CMD  
Description  
Interrupt Delay Enable  
When set, activates the transmit interrupt delay timer. The Ethernet controller loads  
a countdown register when it writes back a transmit descriptor that has RS and IDE  
set. The value loaded comes from the IDV field of the Interrupt Delay (TIDV)  
register. When the count reaches 0, a transmit interrupt occurs if transmit descriptor  
write-back interrupts (IMS.TXDW) are enabled. Hardware always loads the transmit  
interrupt counter whenever it processes a descriptor with IDE set even if it is  
already counting down due to a previous descriptor. If hardware encounters a  
descriptor that has RS set, but not IDE, it generates an interrupt immediately after  
writing back the descriptor. The interrupt delay timer is cleared.  
IDE (bit 7)  
VLAN Packet Enable  
When set, indicates that the packet is a VLAN packet and the Ethernet controller  
should add the VLAN Ethertype and an 802.1q VLAN tag to the packet. The  
Ethertype field comes from the VET register and the VLAN tag comes from the  
special field of the TX descriptor. The hardware inserts the FCS/CRC field in that  
case.  
VLE (bit 6)  
When cleared, the Ethernet controller sends a generic Ethernet packet. The IFCS  
controls the insertion of the FCS field in that case.  
In order to have this capability CTRL.VME bit should also be set, otherwise VLE  
capability is ignored. VLE is valid only when EOP is set.  
Extension (0b for legacy mode).  
DEXT (bit 5)  
Should be written with 0b for future compatibility.  
Report Packet Sent  
When set, the 82544GC/EI defers writing the DD bit in the status byte  
(DESC.STATUS) until the packet has been sent, or transmission results in an error  
such as excessive collisions. It is used is cases where the software must know that  
the packet has been sent, and not just loaded to the transmit FIFO. The 82544GC/  
EI might continue to prefetch data from descriptors logically after the one with RPS  
set, but does not advance the descriptor head pointer or write back any other  
descriptor until it sent the packet with the RPS set. RPS is valid only when EOP is  
set.  
RPS  
RSV (bit 4)  
This bit is reserved and should be programmed to 0b for all Ethernet controllers  
except the 82544GC/EI.  
Report Status  
When set, the Ethernet controller needs to report the status information. This ability  
may be used by software that does in-memory checks of the transmit descriptors to  
determine which ones are done and packets have been buffered in the transmit  
FIFO. Software does it by looking at the descriptor status byte and checking the  
Descriptor Done (DD) bit.  
RS (bit 3)  
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Receive and Transmit Description  
TDESC.CMD  
Description  
Insert Checksum  
When set, the Ethernet controller needs to insert a checksum at the offset indicated  
by the CSO field. The checksum calculations are performed for the entire packet  
starting at the byte indicated by the CCS field. IC is ignored if CSO and CCS are out  
of the packet range. This occurs when (CSS length) OR (CSO length - 1). IC is  
valid only when EOP is set.  
IC (bit 2)  
Insert FCS  
IFCS (bit 1)  
EOP (bit 0)  
Controls the insertion of the FCS/CRC field in normal Ethernet packets. IFCS is  
valid only when EOP is set.  
End Of Packet  
When set, indicates the last descriptor making up the packet. One or many  
descriptors can be used to form a packet.  
Notes:  
1. VLE, IFCS, and IC are qualified by EOP. That is, hardware interprets these bits ONLY when  
EOP is set.  
2. Hardware only sets the DD bit for descriptors with RS set.  
3. Descriptors with the null address (0b) or zero length transfer no data. If they have the RS bit  
set then the DD field in the status word is written when hardware processes them.  
4. Although the transmit interrupt may be delayed, the descriptor write-back requested by setting  
the RS bit is performed without delay unless descriptor write-back bursting is enabled.  
3.3.3.2  
Transmit Descriptor Status Field Format  
The STATUS field stores the applicable transmit descriptor status and has the fields shown in Table  
3-11.  
The transmit descriptor status field is only present in cases where RS (or RPS for the 82544GC/EI  
only) is set in the command field.  
Table 3-11. Transmit Status Layout  
3
2
1
0
RSV  
TUa  
LC  
EC  
DD  
a. 82544GC/EI only.  
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Receive and Transmit Description  
TDESC.STATUS  
Description  
Transmit Underrun  
Indicates a transmit underrun event occurred. Transmit Underrun might occur if Early  
Transmits are enabled (based on ETT.Txthreshold value) and the 82544GC/EI was  
not able to complete the early transmission of the packet due to lack of data in the  
packet buffer. This does not necessarily mean the packet failed to be eventually  
transmitted. The packet is successfully re-transmitted if the TCTL.NRTU bit is  
cleared (and excessive collisions do not occur).  
TU  
RSV (bit 3)  
This bit is reserved and should be programmed to 0b for all Ethernet controllers  
except the 82544GC/EI.  
Late Collision  
Indicates that late collision occurred while working in half-duplex mode. It has no  
meaning while working in full-duplex mode. Note that the collision window is speed  
dependent: 64 bytes for 10/100 Mb/s and 512 bytes for 1000 Mb/s operation.  
LC (bit 2)  
EC (bit 1)  
DD (bit 0)  
Excess Collisions  
Indicates that the packet has experienced more than the maximum excessive  
collisions as defined by TCTL.CT control field and was not transmitted. It has no  
meaning while working in full-duplex mode.  
Descriptor Done  
Indicates that the descriptor is finished and is written back either after the descriptor  
has been processed (with RS set) or for the 82544GC/EI, after the packet has been  
transmitted on the wire (with RPS set).  
Note: The DD bit reflects status of all descriptors up to and including the one with the RS bit set (or RPS  
for the 82544GC/EI).  
3.3.4  
Transmit Descriptor Special Field Format  
The SPECIAL field is used to provide the 802.1q/802.1ac tagging information.  
When CTRL.VME is set to 1b, all packets transmitted from the Ethernet controller that have VLE  
set in the TDESC.CMD are sent with an 802.1Q header added to the packet. The contents of the  
header come from the transmit descriptor special field and from the VLAN type register. The  
special field is ignored if the VLE bit in the transmit descriptor command field is 0b. The special  
field is valid only for descriptors with EOP set to 1b in TDESC.CMD.  
Table 3-12. Special Field (TDESC.SPECIAL) Layout  
15  
13  
12  
11  
0
PRI  
CFI  
VLAN  
TDESC.SPECIAL  
Description  
User Priority  
PRI  
3 bits that provide the VLAN user priority field to be inserted in the 802.1Q tag.  
CFI  
Canonical Form Indicator.  
VLAN Identifier  
VLAN  
12 bits that provide the VLAN identifier field to be inserted in the 802.1Q tag.  
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Receive and Transmit Description  
3.3.5  
TCP/IP Context Transmit Descriptor Format  
The TCP/IP context transmit descriptor provides access to the enhanced checksum offload facility  
available in the Ethernet controller. This feature allows TCP and UDP packet types to be handled  
more efficiently by performing additional work in hardware, thus reducing the software overhead  
associated with preparing these packets for transmission.  
The TCP/IP context transmit descriptor does not point to packet data as a data descriptor does.  
Instead, this descriptor provides access to an on-chip context that supports the transmit checksum  
offloading feature of the controller. A “context” refers to a set of registers loaded or unloaded as a  
group to provide a particular function.  
The context is explicit and directly accessible via the TCP/IP context transmit descriptor. The  
context is used to control the checksum offloading feature for normal packet transmission.  
The Ethernet controller automatically selects the appropriate legacy or normal context to use based  
on the current packet transmission.  
While the architecture supports arbitrary ordering rules for the various descriptors, there are  
restrictions including:  
• Context descriptors should not occur in the middle of a packet.  
• Data descriptors of different packet types (legacy or normal) should not be intermingled  
except at the packet level.  
All contexts control calculation and insertion of up to two checksums. This portion of the context is  
referred to as the checksum context.  
In addition to checksum context, the segmentation context adds information specific to the  
segmentation capability. This additional information includes the total payload for the message  
(TDESC.PAYLEN), the total size of the header (TDESC.HDRLEN), the amount of payload data  
that should be included in each packet (TDESC.MSS), and information about what type of protocol  
(TCP, IPv4, IPv6, etc.) is used. This information is specific to the segmentation capability and is  
therefore ignored for context descriptors that do not have the TSE bit set.  
Because there are dedicated resources on-chip for the normal context, the context remains constant  
until it is modified by another context descriptor. This means that a context can be used for multiple  
packets (or multiple segmentation blocks) unless a new context is loaded prior to each new packet.  
Depending on the environment, it may be completely unnecessary to load a new context for each  
packet. For example, if most traffic generated from a given node is standard TCP frames, this  
context could be set up once and used for many frames. Only when some other frame type is  
required would a new context need to be loaded by software. After the “non-standard” frame is  
transmitted, the “standard” context would be setup once more by software. This method avoids the  
“extra descriptor per packet” penalty for most frames. The penalty can be eliminated altogether if  
software elects to use TCP/IP checksum offloading only for a single frame type, and thus performs  
those operations in software for other frame types.  
This same logic can also be applied to the segmentation context, though the environment is a more  
restrictive one. In this scenario, the host is commonly asked to send a message of the same type,  
TCP/IP for instance, and these messages also have the same total length and same maximum  
segment size (MSS). In this instance, the same segmentation context could be used for multiple  
TCP messages that require hardware segmentation. The limitations of this scenario and the  
relatively small performance advantage make this approach unlikely; however, it is useful in  
understanding the underlying mechanism.  
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Receive and Transmit Description  
3.3.6  
TCP/IP Context Descriptor Layout  
The following section describes the layout of the TCP/IP context transmit descriptor.  
To select this descriptor format, bit 29 (TDESC.DEXT) must be set to 1b and TDESC.DTYP must  
be set to 0000b. In this case, the descriptor format is defined as shown in Table 3-13.  
Note that the TCP/IP context descriptor does not transfer any packet data. It merely prepares the  
checksum hardware for the TCP/IP Data descriptors that follow.  
Table 3-13. Transmit Descriptor (TDESC) Layout – (Type = 0000b)  
63  
48 47  
TUCSO  
HDRLEN RSV STA  
48 47  
40 39  
32 31  
16 15  
IPCSO  
PAYLEN  
8 7  
0
0
8
TUCSE  
MSS  
TUCSS  
IPCSE  
IPCSS  
TUCMD DTYP  
63  
40 39 36 35 32 31  
24 23 20 19  
0
Note: The first quadword of this descriptor type contains parameters used to calculate the two checksums  
which may be offloaded.  
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Receive and Transmit Description  
Table 3-14. Transmit Descriptor (TDESC) Layout  
Transmit  
Descriptor Offload  
Description  
TCP/UDP Checksum Ending  
Defines the ending byte for the TCP/UDP checksum offload feature.  
TUCSE  
Setting TUCSE field to 0b indicates that the checksum covers from TUCCS to the  
end of the packet.  
TCP/UDP Checksum Offset  
Defines the offset where to insert the TCP/UDP checksum field in the packet data  
buffer. This is used in situations where the software needs to calculate partial  
checksums (TCP pseudo-header, for example) to include bytes which are not  
contained within the range of start and end.  
TUCSO  
TUCSS  
If no partial checksum is required, software must write a value of 0b.  
TCP/UDP Checksum Start  
Defines the starting byte for the TCP/UDP checksum offload feature.  
It must be defined even if checksum insertion is not desired for some reason.  
When setting the TCP segmentation context, TUCSS is used to indicate the start  
of the TCP header.  
IP Checksum Ending  
Defines the ending byte for the IP checksum offload feature.  
It specifies where the checksum should stop. A 16-bit value supports checksum  
offloading of packets as large as 64KB.  
IPCSE  
IPCSO  
Setting IPCSE field to 0b indicates that the checksum covers from IPCCS to the  
end of the packet. In this way, the length of the packet does not need to be  
calculated.  
IP Checksum Offset  
The IPCSO field specifies where the resulting IP checksum should be placed. It is  
limited to the first 256 bytes of the packet and must be less than or equal to the  
total length of a given packet. If this is not the case, the checksum is not inserted.  
IP Checksum Start  
IPCSS specifies the byte offset from the start of the transferred data to the first  
byte in be included in the checksum. Setting this value to 0b means the first byte of  
the data would be included in the checksum.  
Note that the maximum value for this field is 255. This is adequate for typical  
applications.  
IPCSS  
The IPCSS value needs to be less than the total transferred length of the packet. If  
this is not the case, the results are unpredictable.  
IPCSS must be defined even if checksum insertion is not desired for some reason.  
When setting the TCP segmentation context, IPCSS is used to indicate the start of  
the IP header.  
Maximum Segment Size  
Controls the Maximum Segment Size. This specifies the maximum TCP or UDP  
payload “segment” sent per frame, not including any header. The total length of  
each frame (or “section”) sent by the TCP Segmentation mechanism (excluding  
802.3ac tagging and Ethernet CRC) is MSS bytes + HRDLEN. The one exception  
is the last packet of a TCP segmentation context which is (typically) shorter than  
“MSS+HDRLEN”. This field is ignored if TDESC.TSE is not set.  
MSS  
Header Length  
Specifies the length (in bytes) of the header to be used for each frame (or  
“section”) of a TCP Segmentation operation. The first HDRLEN bytes fetched from  
data descriptor(s) are stored internally and used as a prototype header for each  
section, and are pre-pended to each payload segment to form individual frames.  
For UDP packets this is normally equal to “UDP checksum offset + 2”. For TCP  
packets it is normally equal to “TCP checksum offset + 4 + TCP header option  
bytes”. This field is ignored if TDESC.TSE is not set.  
HDRLEN  
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Receive and Transmit Description  
Transmit  
Descriptor Offload  
Description  
Reserved  
RSV  
STA  
Should be programmed to 0b for future compatibility.  
TCP/UDP Status field  
Provides transmit status indication.  
Section 3.3.6.2 provides the bit definition for the TDESC.STA field.  
TCP/UDP command field  
The command field provides options that control the checksum offloading, along  
with some of the generic descriptor processing functions.  
TUCMD  
DTYP  
Section 3.3.6.1 provides the bit definitions for the TDESC.TUCMD field.  
Descriptor Type  
Set to 0000b for TCP/IP context transmit descriptor type.  
The packet length field (TDESC.PAYLEN) is the total number of payload bytes for  
this TCP Segmentation offload context (i.e., the total number of payload bytes that  
could be distributed across multiply frames after TCP segmentation is performed).  
Following the fetch of the prototype header, PAYLEN specifies the length of data  
that is fetched next from data descriptor(s). This field is also used to determine  
when “last-frame” processing needs to be performed. Typically, a new data  
descriptor is used to denote the start of the payload data buffer(s), but this is not  
required. PAYLEN specification should not include any header bytes. There is no  
restriction on the overall PAYLEN specification with respect to the transmit FIFO  
size, once the MSS and HDRLEN specifications are legal. This field is ignored if  
TDESC.TSE is not set. Refer to Section 3.5 for details on the TCP Segmentation  
off-loading feature.  
PAYLEN  
Notes:  
1. A number of the fields are ignored if the TCP Segmentation enable bit (TDESC.TSE) is  
cleared, denoting that the descriptor does not refer to the TCP segmentation context.  
2. Maximum limits for the HDRLEN and MSS fields are dictated by the lengths variables. How-  
ever, there is a further restriction that for any TCP Segmentation operation, the hardware must  
be capable of storing a complete section (completely-built frame) in the transmit FIFO prior to  
transmission. Therefore, the sum of MSS + HDRLEN must be at least 80 bytes less than the  
allocated size of the transmit FIFO.  
3.3.6.1  
TCP/UDP Offload Transmit Descriptor Command Field  
The command field (TDESC.TUCMD) provides options to control the TCP segmentation, along  
with some of the generic descriptor processing functions.  
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Receive and Transmit Description  
Table 3-15. Command Field (TDESC.TUCMD) Layout  
7
6
5
4
3
2
1
0
IDE  
RSV  
DEXT  
RSV  
RS  
TSE  
IP  
TCP  
TDESC.TUCMD  
Description  
Interrupt Delay Enable  
IDE activates the transmit interrupt delay timer. Hardware loads a countdown  
register when it writes back a transmit descriptor that has the RS bit and the IDE bit  
set. The value loaded comes from the IDV field of the Interrupt Delay (TIDV) register.  
When the count reaches 0, a transmit interrupt occurs. Hardware always loads the  
transmit interrupt counter whenever it processes a descriptor with IDE set even if it is  
already counting down due to a previous descriptor. If hardware encounters a  
descriptor that has RS set, but not IDE, it generates an interrupt immediately after  
writing back the descriptor. The interrupt delay timer is cleared.  
IDE (bit 7)  
RSV (Bit 6)  
DEXT(Bit 5)  
RSV (Bit 4)  
Reserved. Set to 0b for future compatibility.  
Descriptor Extension  
Must be 1b for this descriptor type.  
Reserved. Set to 0b for future compatibility.  
Report Status  
RS tells the hardware to report the status information for this descriptor. Because this  
descriptor does not transmit data, only the DD bit in the status word is valid. Refer to  
Section 3.3.6.2 for the layout of the status field.  
RS (Bit 3)  
TCP Segmentation Enable  
TSE indicates that this descriptor is setting the TCP segmentation context. If this bit  
is not set, the checksum offloading context for normal (non-”TCP Segmentation”)  
packets is written. When a descriptor of this type is processed the Ethernet controller  
immediately updates the context in question (TCP Segmentation or checksum  
offloading) with values from the descriptor. This means that if any normal packets or  
TCP Segmentation packets are in progress (a descriptor with EOP set has not been  
received for the given context), the results are likely to be undesirable.  
TSE (Bit 2)  
Packet Type (IPv4 = 1b, IPv6 = 0b)  
Identifies what type of IP packet is used in the segmentation process. This is  
necessary for hardware to know where the IP Payload Length field is located. This  
does not override the checksum insertion bit, IXSM.  
IP (Bit 1)  
IP (Bit 1)  
Packet Type (IP = 1b)  
Identifies the packet as an IP packet. The purpose of this bit is to enable/disable the  
82544GC/EI only updating of the IP header during the segmentation process. This does not override  
the checksum insertion bit, IXSM.  
Packet Type (TCP = 1b)  
TCP (bit 0)  
Identifies the packet as either TCP or UDP (non-TCP). This affects the processing of  
the header information.  
Note:  
1. The IDE, DEXT, and RS bits are valid regardless of the state of TSE. All other bits are ignored  
if TSE = 0b.  
2. The TCP Segmentation feature also provides access to a generic block send function and may  
be useful for performing “segmentation offload” in which the header information is constant.  
By clearing both the TCP and IP bits, a block of data may be broken down into frames of a  
given size, a constant, arbitrary length header may be pre-pended to each frame, and two  
checksums optionally added.  
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Receive and Transmit Description  
3.3.6.2  
TCP/UDP Offload Transmit Descriptor Status Field  
Four bits are reserved to provide transmit status, although only one is currently assigned for this  
specific descriptor type. The status word is only written back to host memory in cases where the RS  
is set in the command.  
Table 3-16. Transmit Status Layout  
3
2
1
0
RSV  
DD  
TDESC.STA  
Description  
Reserved  
RSV  
Reserved for future use. Reads as 0b.  
Descriptor Done  
DD (bit 0)  
Indicates that the descriptor is finished and is written back after the descriptor has  
been processed.  
3.3.7  
TCP/IP Data Descriptor Format  
The TCP/IP data descriptor is the companion to the TCP/IP context transmit descriptor described  
in the previous section. This descriptor type provides similar functionality to the legacy mode  
descriptor but also integrates the checksum offloading and TCP Segmentation feature.  
To select this descriptor format, bit 29 in the command field (TDESC.DEXT) must be set to 1b and  
TDESC.DTYP must be set to 0001b. In this case, the descriptor format is defined as shown in  
Table 3-17.  
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Receive and Transmit Description  
Table 3-17. Transmit Descriptor (TDESC) Layout – (Type = 0001b)  
0
8
0
Address [63:0]  
RSV STA  
Special  
POPTS  
DCMD  
DTYP  
DTALEN  
63  
48 47  
40 39 36 35 32 31  
24 23 20 19  
0
Transmit Descriptor  
Description  
Data buffer address  
Address  
Address of the data buffer in the host memory which contains a portion of the  
transmit packet.  
Data Length Field  
Total length of the data pointed to by this descriptor, in bytes.  
For data descriptors not associated with a TCP Segmentation operation  
DTALEN  
(TDESC.TSE not set), the descriptor lengths are subject to the same restrictions  
specified for legacy descriptors (the sum of the lengths of the data descriptors  
comprising a single packet must be at least 80 bytes less than the allocated size  
of the transmit FIFO.)  
Data Type  
DTYP  
Set to 0001b to identify this descriptor as a TCP/IP data descriptor.  
Descriptor Command Field  
DCMD  
Provides options that control some of the generic descriptor processing  
features. Refer to Section 3.3.7.1 for bit definitions of the DCMD field.  
TCP/IP Status field  
STA  
Provides transmit status indication.  
Section 3.3.7.2 provides the bit definition for the TDESC.STA field.  
Reserved  
RSV  
Set to 0b for future compatibility.  
Packet Option Field  
Provides a number of options which control the handling of this packet. This field  
is ignored except on the first data descriptor of a packet.  
POPTS  
Special  
Section 3.3.7.3 provides the bit definition for the TDESC.POPTS field.  
Special field  
The Special field is used to provide 802.1q tagging information.  
This field is only valid in the last descriptor of the given packet (qualified by the  
EOP bit).  
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Receive and Transmit Description  
3.3.7.1  
TCP/IP Data Descriptor Command Field  
The Command field provides options that control checksum offloading and TCP segmentation  
features along with some of the generic descriptor processing features.  
Table 3-18. Command Field (TDESC.DCMD) Layout  
7
6
5
4
3
2
1
0
RSV  
RPSa  
IDE  
VLE  
DEXT  
RS  
TSE  
IFCS  
EOP  
a. 82544GC/EI only.  
TDESC.DCMD  
Description  
Interrupt Delay Enable  
When set, activates the transmit interrupt delay timer. Hardware loads a countdown  
register when it writes back a transmit descriptor that has RS and IDE set. The value  
loaded comes from the IDV field of the Interrupt Delay (TIDV) register. When the  
count reaches 0, a transmit interrupt occurs if enabled. Hardware always loads the  
transmit interrupt counter whenever it processes a descriptor with IDE set even if it is  
already counting down due to a previous descriptor. If hardware encounters a  
descriptor that has RS set, but not IDE, it generates an interrupt immediately after  
writing back the descriptor. The interrupt delay timer is cleared.  
IDE (bit 7)  
VLAN Enable  
When set, indicates that the packet is a VLAN packet and the hardware should add  
the VLAN Ethertype and an 802.1q VLAN tag to the packet. The Ethertype should  
come from the VET register and the VLAN data comes from the special field of the TX  
descriptor. The hardware in that case appends the FCS/CRC.  
VLE (bit 6)  
Note that the CTRL.VME bit should also be set. If the CTRL.VME bit is not set, the  
Ethernet controller does not insert VLAN tags on outgoing packets and it sends  
generic Ethernet packets. The IFCS controls the insertion of the FCS/CRC in that  
case.  
VLE is only valid in the last descriptor of the given packet (qualified by the EOP bit).  
Descriptor Extension  
DEXT (Bit 5)  
Must be 1b for this descriptor type  
Report Packet Sent  
RPS is used in cases where software must know that a packet has been sent on the  
wire, not just that it has been loaded into the 82544GC/EI controller’s internal packet  
buffer.  
When set, hardware defers writing the DD bit in the status byte until the packet has  
been sent, or transmission results in an error such as excess collisions. Hardware  
can continue to pre-fetch data from descriptors logically after the one with RPS set,  
but does not advance the head pointer or write back any other descriptors until it has  
sent the packet with RPS set.  
RPS  
RSV (bit 4)  
For a TCP Segmentation context, the RPS bit indicates to the 82544GC/EI that the  
descriptor status should only be written back once all packets that make up the given  
TCP Segmentation context had been sent.  
This bit is reserved and should be programmed to 0b for all Ethernet controllers  
except the 82544GC/EI.  
Report Status  
When set, tells the hardware to report the status information for this descriptor as  
soon as the corresponding data buffer has been fetched and stored in the controller’s  
internal packet buffer.  
RS (bit 3)  
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Receive and Transmit Description  
TDESC.DCMD  
Description  
TCP Segmentation Enable  
TSE (bit 2)  
TSE indicates that this descriptor is part of the current TCP Segmentation context. If  
this bit is not set, the descriptor is part of the “normal” context.  
Insert IFCS  
IFCS (Bit 1)  
EOP (Bit 0)  
Controls the insertion of the FCS/CRC field in normal Ethernet packets.  
IFCS is only valid in the last descriptor of the given packet (qualified by the EOP bit).  
End Of Packet  
The EOP bit indicates that the buffer associated with this descriptor contains the last  
data for the packet or for the given TCP Segmentation context. In the case of a TCP  
Segmentation context, the DTALEN length of this descriptor should match the  
amount remaining of the original PAYLEN. If it does not, the TCP Segmentation  
context is terminated but the end of packet processing may be incorrectly performed.  
These abnormal termination events are counted in the TSCTFC statistics register.  
Note: The VLE, IFCS, and VLAN fields are only valid in certain descriptors. If TSE is enabled, the VLE,  
IFCS, and VLAN fields are only valid in the first data descriptor of the TCP segmentation context.  
If TSE is not enabled, then these fields are only valid in the last descriptor of the given packet  
(qualified by the EOP bit).  
3.3.7.2  
TCP/IP Data Descriptor Status Field  
Four bits are reserved to provide transmit status, although only the DD is valid1. The status word is  
only written back to host memory in cases where the RS bit is set in the command field. The DD bit  
indicates that the descriptor is finished and is written back after the descriptor has been processed.  
Table 3-19. Transmit Status Layout  
3
2
1
0
RSV  
TUa  
LC  
EC  
DD  
a. 82544GC/EI only.  
TDESC.STA  
Description  
Reserved  
Reserved  
1. Unless the RPS bit is set in the descriptor (82544GC/EI only).  
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Receive and Transmit Description  
TDESC.STA  
Description  
Late Collision  
Indicates that late collision occurred while working in half-duplex mode.  
It has no meaning while working in full-duplex mode.  
LC (bit2)  
Note that the collision window is speed dependent: 64 bytes for 10/100 Mb/s and  
512 bytes for 1000 Mb/s operation.  
Excess Collision  
Indicates that the packet has experienced more than the maximum excessive  
collisions as defined by TCTL.CT control field and was not transmitted.  
EC (bit 1)  
DD (bit 0)  
Is has no meaning while working in full-duplex mode.  
Descriptor Done  
Indicates that the descriptor is done and is written back either after the descriptor  
has been processed (with RS set), or for the 82554GC/EI only, after the packet has  
been transmitted on the wire (with RPS set).  
3.3.7.3  
TCP/IP Data Descriptor Option Field  
The POPTS field provides a number of options which control the handling of this packet. This field  
is ignored except on the first data descriptor of a packet.  
Table 3-20. Packet Options Field (TDESC.POPTS) Layout  
7
6
5
4
3
2
1
0
RSV  
RSV  
RSV  
RSV  
RSV  
RSV  
TXSM  
IXSM  
TDESC.POPTS  
Description  
Reserved  
RSV (bit 2-7)  
Should be written with 0b for future compatibility.  
Insert TCP/UDP Checksum  
Controls the insertion of the TCP/UDP checksum.  
If not set, the value placed into the checksum field of the packet data is not modified,  
and is placed on the wire. When set, TCP/UDP checksum field is modified by the  
hardware.  
TXSM (bit1)  
IXSM (bit 0)  
Valid only in the first data descriptor for a given packet or TCP Segmentation context.  
Insert IP Checksum  
Controls the insertion of the IP checksum.  
If not set, the value placed into the checksum field of the packet data is not modified  
and is placed on the wire. When set, the IP checksum field is modified by the  
hardware.  
Valid only in the first data descriptor for a given packet or TCP Segmentation context.  
3.3.7.4  
TCP/IP Data Descriptor Special Field  
The SPECIAL field is used to provide the 802.1q/802.3ac tagging information.  
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Receive and Transmit Description  
When CTRL.VME is set to 1b, all packets transmitted from the Ethernet controller that has VLE  
set in the DCMD field is sent with an 802.1Q header added to the packet. The contents of the  
header come from the transmit descriptor special field and from the VLAN type register. The  
special field is ignored if the VLE bit in the transmit descriptor command field is 0b. The special  
field is valid only when EOP is set.  
Table 3-21. Special Field (TDESC.SPECIAL) Layout  
15  
13  
12  
11  
0
PRI  
CFI  
VLAN  
TDESC.SPECIAL  
Description  
User Priority  
PRI  
Three bits that provide the VLAN user priority field to be inserted in the 802.1Q tag.  
CFI  
Canonical Form Indicator  
VLAN Identifier  
VLAN  
12 bits that provide the VLAN identifier field to be inserted in the 802.1Q tag.  
3.4  
Transmit Descriptor Ring Structure  
The transmit descriptor ring structure is shown in Figure 3-4. A pair of hardware registers  
maintains the transmit queue. New descriptors are added to the ring by writing descriptors into the  
circular buffer memory region and moving the ring’s tail pointer. The tail pointer points one entry  
beyond the last hardware owned descriptor (but at a point still within the descriptor ring).  
Transmission continues up to the descriptor where head equals tail at which point the queue is  
empty.  
Descriptors passed to hardware should not be manipulated by software until the head pointer has  
advanced past them.  
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Receive and Transmit Description  
Circular Buffer  
Base  
Head  
Owned By  
Hardware  
Transmit  
Queue  
Tail  
Base + Size  
Figure 3-4. Transmit Descriptor Ring Structure  
Shaded boxes in Figure 3-4 represent descriptors that have been transmitted but not yet reclaimed  
by software. Reclaiming involves freeing up buffers associated with the descriptors.  
The transmit descriptor ring is described by the following registers:  
• Transmit Descriptor Base Address registers (TDBAL and TDBAH)  
These registers indicate the start of the descriptor ring buffer. This 64-bit address is aligned on  
a 16-byte boundary and is stored in two consecutive 32-bit registers. TDBAL contains the  
lower 32-bits; TDBAH contains the upper 32 bits. Hardware ignores the lower 4 bits in  
TDBAL.  
• Transmit Descriptor Length register (TDLEN)  
This register determines the number of bytes allocated to the circular buffer. This value must  
be 128 byte aligned.  
• Transmit Descriptor Head register (TDH)  
This register holds a value which is an offset from the base, and indicates the in–progress  
descriptor. There can be up to 64K descriptors in the circular buffer. Reading this register  
returns the value of “head” corresponding to descriptors already loaded in the output FIFO.  
• Transmit Descriptor Tail register (TDT)  
This register holds a value which is an offset from the base, and indicates the location beyond  
the last descriptor hardware can process. This is the location where software writes the first  
new descriptor.  
The base register indicates the start of the circular descriptor queue and the length register indicates  
the maximum size of the descriptor ring. The lower seven bits of length are hard–wired to 0b. Byte  
addresses within the descriptor buffer are computed as follows:  
address = base + (ptr * 16), where ptr is the value in the hardware head or tail register.  
The size chosen for the head and tail registers permit a maximum of 64 K descriptors, or  
approximately 16 K packets for the transmit queue given an average of four descriptors per packet.  
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Receive and Transmit Description  
Once activated, hardware fetches the descriptor indicated by the hardware head register. The  
hardware tail register points one beyond the last valid descriptor.  
Software can determine if a packet has been sent by setting the RS bit (or the RPS bit for the  
82544GC/EI only) in the transmit descriptor command field. Checking the transmit descriptor DD  
bit in memory eliminates a potential race condition. All descriptor data is written to the IO bus  
prior to incrementing the head register, but a read of the head register could “pass” the data write in  
systems performing IO write buffering. Updates to transmit descriptors use the same IO write path  
and follow all data writes. Consequently, they are not subject to the race condition. Other potential  
conditions also prohibit software reading the head pointer.  
In general, hardware prefetches packet data prior to transmission. Hardware typically updates the  
value of the head pointer after storing data in the transmit FIFO1.  
The process of checking for completed packets consists of one of the following:  
• Scan memory for descriptor status write-backs.  
• Take an interrupt. An interrupt condition can be generated whenever a transmit queue goes  
empty (ICR.TXQE). Interrupts can also be triggered in other ways.  
3.4.1  
Transmit Descriptor Fetching  
The descriptor processing strategy for transmit descriptors is essentially the same as for receive  
descriptors except that a different set of thresholds are used. As for receives, the number of on-chip  
transmit descriptors buffer space is 64 descriptors.  
When the on-chip buffer is empty, a fetch happens as soon as any descriptors are made available  
(software writes to the tail pointer). When the on-chip buffer is nearly empty  
(TXDCTL.PTHRESH), a prefetch is performed whenever enough valid descriptors  
(TXDCTL.HTHRESH) are available in host memory and no other DMA activity of greater priority  
is pending (descriptor fetches and write-backs or packet data transfers).  
The descriptor prefetch policy is aggressive to maximize performance. If descriptors reside in an  
external cache, the system must ensure cache coherency before changing the tail pointer.  
When the number of descriptors in host memory is greater than the available on-chip descriptor  
storage, the chip may elect to perform a fetch which is not a multiple of cache line size. The  
hardware performs this non-aligned fetch if doing so results in the next descriptor fetch being  
aligned on a cache line boundary. This allows the descriptor fetch mechanism to be most efficient  
in the cases where it has fallen behind software.  
3.4.2  
Transmit Descriptor Write-back  
The descriptor write-back policy for transmit descriptors is similar to that for receive descriptors  
with a few additional factors. First, since transmit descriptor write-backs are optional (controlled  
by RS2 in the transmit descriptor), only descriptors which have one (or both) of these bits set starts  
the accumulation of write-back descriptors. Secondly, to preserve backward compatibility with the  
82542, if the TXDCTL.WTHRESH value is 0b, the Ethernet controller writes back a single byte of  
the descriptor (TDESCR.STA) and all other bytes of the descriptor are left unchanged.  
1. With the RPS bit set, the head is not advanced until after the packet is transmitted or rejected due to excess collisions (82544GC/EI only).  
2. And RPS for the 82544GC/EI only.  
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Receive and Transmit Description  
Since the benefit of delaying and then bursting transmit descriptor write-backs is small at best, it is  
likely that the threshold are left at the default value (0b) to force immediate write-back of transmit  
descriptors and to preserve backward compatibility.  
Descriptors are written back in one of three conditions:  
• TXDCTL.WTHRESH = 0b and a descriptor which has RS1 set is ready to be written back  
• Transmit Interrupt Delay timer expires  
• TXDCTL.WTHRESH > 0b and TXDCTL.WTHRESH descriptors have accumulated  
For the first condition, write-backs are immediate. This is the default operation and is backward  
compatible. For this case, the Transmit Interrupt delay function works as described in Section  
3.4.3.1.  
The other two conditions are only valid if descriptor bursting is enabled (see Section 13.4.44). In  
the second condition, the Transmit Interrupt Delay timer (TIDV) is used to force timely write–back  
of descriptors. The first packet after timer initialization starts the timer. Timer expiration flushes  
any accumulated descriptors and sets an interrupt event (TXDW).  
For the final condition, if TXDCTL.WTHRESH descriptors are ready for write-back, the write-  
back is performed.  
3.4.3  
Transmit Interrupts  
Hardware supplies three transmit interrupts. These interrupts are initiated through the following  
conditions:  
• Transmit queue empty (TXQE) — All descriptors have been processed. The head pointer is  
equal to the tail pointer.  
• Descriptor done [Transmit Descriptor Write-back (TXDW)] — Set when hardware writes  
back a descriptor with RS1 set. This is only expected to be used in cases where, for example,  
the streams interface has run out of descriptors and wants to be interrupted whenever progress  
is made.  
• Transmit Delayed Interrupt (TXDW) — In conjunction with IDE (Interrupt Delay Enable), the  
TXDW indication is delayed by a specific time per the TIDV register. This interrupt is set  
when the transmit interrupt countdown register expires. The countdown register is loaded with  
the value of the IDV field of the TIDV register, when a transmit descriptor with its RS1 bit and  
the IDE bit are set, is written back. When a Transmit Delayed Interrupt occurs, the TXDW  
interrupt cause bit is set (just as when a Transmit Descriptor Write-back interrupt occurs). This  
interrupt may be masked in the same manner as the TXDW interrupt. This interrupt is used  
frequently by software that performs dynamic transmit chaining, by adding packets one at a  
time to the transmit chain.  
Note: The transmit delay interrupt is indicated with the same interrupt bit as the transmit write-back  
interrupt, TXDW. The transmit delay interrupt is only delayed in time as discussed above.  
1. Or RPS for the 82544GC/EI only.  
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Receive and Transmit Description  
• Link status change (LSC) - Set when the link status changes. When using the internal PHY,  
link status changes are determined and indicated by the PHY via a change in its LINK  
indication.  
When using an external TBI device (82544GC/EI only), the device might indicate a link  
status change using its LOS (loss of sync) indication. In this TBI mode, if HW Auto-  
Negotiation is enabled, the MAC can also detect and signal a link status change if the  
Configuration Base Page register is received (0b), or if either the LRST or ANE bits are  
changed by software.  
• Transmit Descriptor Ring Low Threshold Hit (TXD_LOW) (not applicable to the 82544GC/  
EI) - Set when the total number of transmit descriptors available (as measured by the  
difference between the Tx descriptor ring Head and Tail pointer) hits the low threshold  
specified in the TXDCTL.LWTHRESH field.  
3.4.3.1  
Delayed Transmit Interrupts  
This mechanism allows software the flexibility of delaying transmit interrupts until no more  
descriptors are added to a transmit chain for a certain amount of time, rather than when the Ethernet  
controller’s head pointer catches the tail pointer. This occurs if the Ethernet controller is processing  
packets slightly faster than the software, a likely scenario for gigabit operations.  
A software driver usually has no knowledge of when it is going to be asked to send another frame.  
For performance reasons, it is best to generate only one transmit interrupt after a burst of packets  
have been sent.  
Refer to Section 3.3.3.1 for specific details.  
3.5  
TCP Segmentation  
Hardware TCP Segmentation is one of the off-loading options of most modern TCP/IP stacks. This  
is often referred to as “Large Send” offloading. This feature enables the TCP/IP stack to pass to the  
Ethernet controller software driver a message to be transmitted that is bigger than the Maximum  
Transmission Unit (MTU) of the medium. It is then the responsibility of the software driver and  
hardware to carve the TCP message into MTU size frames that have appropriate layer 2 (Ethernet),  
3 (IP), and 4 (TCP) headers. These headers must include sequence number, checksum fields,  
options and flag values as required. Note that some of these values (such as the checksum values)  
are unique for each packet of the TCP message, and other fields such as the source IP address is  
constant for all packets associated with the TCP message.  
The offloading of these processes from the software driver to the Ethernet controller saves  
significant CPU cycles. The software driver shares the additional tasks to support these options  
with the Ethernet controller.  
Although the Ethernet controller’s TCP segmentation offload implementation was specifically  
designed to take advantage of new “TCP Segmentation offload” features, the hardware  
implementation was made generic enough so that it could also be used to “segment” traffic from  
other protocols. For instance this feature could be used any time it is desirable for hardware to  
segment a large block of data for transmission into multiple packets that contain the same generic  
header.  
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Receive and Transmit Description  
3.5.1  
Assumptions  
The following assumption applies to the TCP Segmentation implementation in the Ethernet  
controller:  
• The RS bit operation is not changed. Interrupts are set after data in buffers pointed to by  
individual descriptors is transferred to hardware.  
• Checksums are not accurate above a 12 K frame size.  
• The function of the RPS1 bit in the Transmit Descriptor is applicable to all of the packets that  
make up the “TCP Segmentation” context, not the individual packets segmented by hardware.  
3.5.2  
Transmission Process  
The transmission process for regular (non-TCP Segmentation packets) involves:  
• The protocol stack receives from an application a block of data that is to be transmitted.  
• The protocol stack calculates the number of packets required to transmit this block based on  
the MTU size of the media and required packet headers.  
• For each packet of the data block:  
• Ethernet, IP and TCP/UDP headers are prepared by the stack.  
• The stack interfaces with the software device driver and commands the driver to send the  
individual packet.  
• The driver gets the frame and interfaces with the hardware.  
• The hardware reads the packet from host memory (via DMA transfers).  
• The driver returns ownership of the packet to the operating system when the hardware has  
completed the DMA transfer of the frame (indicated by an interrupt).  
The transmission process for the Ethernet controller TCP segmentation offload implementation  
involves:  
• The protocol stack receives from an application a block of data that is to be transmitted.  
• The stack interfaces to the software device driver and passes the block down with the  
appropriate header information.  
• The software device driver sets up the interface to the hardware (via descriptors) for the TCP  
Segmentation context.  
• The hardware transfers the packet data and performs the Ethernet packet segmentation and  
transmission based on offset and payload length parameters in the TCP/IP context descriptor  
including:  
— Packet encapsulation  
— Header generation & field updates including IP and TCP/UDP checksum generation  
— The driver returns ownership of the block of data to the operating system when the  
hardware has completed the DMA transfer of the entire data block (indicated by an  
interrupt).  
1. 82544GC/EI only.  
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Receive and Transmit Description  
3.5.2.1  
TCP Segmentation Data Fetch Control  
To perform TCP Segmentation in the Ethernet controller, the DMA unit must ensure that the entire  
payload of the segmented packet fits into the available space in the on-chip Packet Buffer. The  
segmentation process is performed without interruption. The DMA performs various comparisons  
between the payload and the Packet Buffer to ensure that no interruptions occur. The TCP  
Segmentation Pad & Minimum Threshold (TSPMT) register is used to allow software to program  
the minimum threshold required for a TCP Segmentation payload. Consideration should be made  
for the MTU value when writing this field. The TSPMT register is also used to program the  
threshold padding overhead. This padding is necessary due to the indeterminate nature of the MTU  
and the associated headers.  
3.5.3  
TCP Segmentation Performance  
Performance improvements for a hardware implementation of TCP Segmentation offload mean:  
• The operating system stack does not need to partition the block to fit the MTU size, saving  
CPU cycles.  
• The operating system stack only computes one Ethernet, IP, and TCP header per segment,  
saving CPU cycles.  
• The operating system stack interfaces with the software device driver only once per block  
transfer, instead of once per frame.  
• Larger PCI bursts are used which improves bus efficiency.  
• Interrupts are easily reduced to one per TCP message instead of one per packet.  
• Fewer I/O accesses are required to command the hardware.  
3.5.4  
Packet Format  
Typical TCP/IP transmit window size is 8760 bytes (about 6 full size frames). A TCP message can  
be as large as 64 KB and is generally fragmented across multiple pages in host memory. The  
Ethernet controller partitions the data packet into standard Ethernet frames prior to transmission.  
The Ethernet controller supports calculating the Ethernet, IP, TCP, and even UDP headers,  
including checksum, on a frame by frame basis.  
Ethernet  
IPv4  
TCP/UDP  
DATA  
FCS  
Figure 3-5. TCP/IP Packet Format  
Frame formats supported by the Ethernet controller’s TCP segmentation include:  
• Ethernet 802.3  
• IEEE 802.1q VLAN (Ethernet 802.3ac)  
• Ethernet Type 2  
• Ethernet SNAP  
• IPv4 headers with options  
• IPv6 headers with IP option next headers  
• IPv6 packet tunneled in IPv4  
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Receive and Transmit Description  
• TCP with options  
• UDP with limitations.  
UDP (unlike TCP) is not a “reliable protocol”, and fragmentation is not supported at the UDP  
level. UDP messages that are larger than the MTU size of the given network medium are normally  
fragmented at the IP layer. This is different from TCP, where large TCP messages can be  
fragmented at either the IP or TCP layers depending on the software implementation. The Ethernet  
controller has the ability to segment UDP traffic (in addition to TCP traffic). This process has  
limited usefulness.  
IP tunneled packets are not supported for TCP Segmentation operation1.  
3.5.5  
TCP Segmentation Indication  
Software indicates a TCP Segmentation transmission context to the hardware by setting up a TCP/  
IP Context Transmit Descriptor. The purpose of this descriptor is to provide information to the  
hardware to be used during the TCP segmentation offload process. The layout of this descriptor is  
reproduced in Section 3.3.6.  
63  
63  
48 47  
40 39  
32 31  
16 15  
IPCS0  
8
7
0
0
TUCSE  
MSS  
TUCS0  
HDRLEN  
TUCSS  
RSV STA  
IPCSE  
TUCMD DTYP  
IPCSS  
8
PAYLEN  
48 47  
40 3936 35 32 31  
24 23 20 19  
0
7
6
5
4
3
2
TSE  
1
0
IDE  
RSV  
DEXT  
RSV  
RS  
IP  
TCP  
Figure 3-6. TCP/IP Context Transmit Descriptor & Command Layout  
Setting the TSE bit in the Command field to 1b indicates that this descriptor refers to the TCP  
Segmentation context (as opposed to the normal checksum offloading context). This causes the  
checksum offloading, packet length, header length, and maximum segment size parameters to be  
loaded from the descriptor into the Ethernet controller.  
The TCP Segmentation prototype header is taken from the packet data itself. Software must  
identity the type of packet that is being sent (IP/TCP, IP/UDP, other), calculate appropriate  
checksum offloading values for the desired checksums, and calculate the length of the header  
which is pre-pended. The header may be up to 240 bytes in length.  
Once the TCP Segmentation context has been set, the next descriptor provides the initial data to  
transfer. This first descriptor(s) must point to a packet of the type indicated. Furthermore, the data it  
points to may need to be modified by software as it serves as the prototype header for all packets  
within the TCP Segmentation context. The following sections describe the supported packet types  
and the various updates which are performed by hardware. This should be used as a guide to  
determine what must be modified in the original packet header to make it a suitable prototype  
header.  
The following summarizes the fields considered by the driver for modification in constructing the  
prototype header:  
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Receive and Transmit Description  
• IPv4 Header  
— Length should be set to zero  
— Identification Field should be set as appropriate for first packet of send (if not already)  
— Header Checksum should be zeroed out unless some adjustment is needed by the driver  
• IPv6 Header  
— Length should be set to zero  
• TCP Header  
— Sequence Number should be set as appropriate for first packet of send (if not already)  
— PSH, and FIN flags should be set as appropriate for last packet of send  
— TCP Checksum should be set to the partial pseudo-header checksum as follows:  
IP Source Address  
IP Destination Address  
Zero  
Zero  
Next Header  
Zeroa  
Layer 4  
Zeroa  
a. 82544GC/EI only  
Protocola  
Figure 3-7. TCP Partial Pseudo-Header Checksum  
• UDP Header  
— Checksum should be set as in TCP header, above  
The Ethernet controller’s DMA function fetches the ethernet, IP, and TCP/UDP prototype header  
information from the initial descriptor(s) and save them on-chip for individual packet header gen-  
eration. The following sections describe the updating process performed by the hardware for each  
frame sent using the TCP Segmentation capability.  
3.5.6  
TCP Segmentation Use of Multiple Data Descriptors  
TCP Segmentation enables a packet to be segmented to describe more than one data descriptor. A  
large packet contained in a single virtual-address buffer is better described as a series of data  
descriptors, each referencing a single physical address page.  
The only requirement for this use is if multiple data descriptors for TCP segmentation follows this  
guideline:  
• If multiple data descriptors are used to describe the IP/TCP/UDP header section, each  
descriptor must describe one or more complete headers; descriptors referencing only parts of  
headers are not supported.  
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Receive and Transmit Description  
Note: It is recommended that the entire header section, as described by the TCP Context Descriptor  
HDRLEN field, be coalesced into a single buffer and described using a single data descriptor.  
3.5.7  
IP and TCP/UDP Headers  
This section outlines the format and content for the IP, TCP and UDP headers. The Ethernet  
controller requires baseline information from the software device driver in order to construct the  
appropriate header information during the segmentation process.  
Header fields that are modified by the Ethernet controller are highlighted in the figures that follow.  
The IPv4 header is first shown in the traditional (RFC 791) representation, and because byte and bit  
ordering is confusing in that representation, the IP header is also shown in little-endian format. The  
actual data is fetched from memory in little-endian format.  
1
0
2
0
3
0
0
1
2
3
4
5
6
7
8
9
1 2  
3
4
5
6
7
8
9
1
2
3 4  
5
6 7  
8
9
1
IP Hdr  
Length  
Version  
TYPE of service  
Total length  
Identification  
Layer 4 Protocol ID  
Flags  
Fragment Offset  
Header Checksum  
Time to Live  
Source Address  
Destination Address  
Options  
Figure 3-8. IPv4 Header (Traditional Representation)  
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Receive and Transmit Description  
Byte 3  
Byte 2  
Byte 1  
Byte 0  
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
IP Hdr  
Length  
LSB  
Total length  
MSB  
TYPE of service  
Version  
R
E
S
N
F
M
F
Fragment  
Offset High  
Fragment Offset Low  
LSB  
Identification  
MSB  
Header Checksum  
Layer 4 Protocol ID  
Time to Live  
Source Address  
Destination Address  
Options  
Figure 3-9. IPv4 Header (Little-Endian Order)  
Flags Field Definition:  
The Flags field is defined below. Note that hardware does not evaluate or change these bits.  
• MF  
More Fragments  
No Fragments  
• NF  
• Reserved  
Note: The IPv6 header is first shown in the traditional (RFC 2460), big-endian representation. The actual  
data is fetched from memory in little-endian format.  
1
2
3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
Version  
Traffic Class  
Payload Length  
Flow Label  
Next Header  
Source Address  
Destination Address  
Hop Limit  
Figure 3-10. IPv6 TCP Header (Traditional Representation)  
A TCP or UDP frame uses a 16 bit wide one’s complement checksum. The checksum word is  
computed on the outgoing TCP or UDP header and payload, and on the Pseudo Header. Details on  
checksum computations are provided in Section 3.5. TCP requires the use of checksum, where it is  
optional for UDP.  
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Receive and Transmit Description  
The TCP header is first shown in the traditional (RFC 793) representation. Because byte and bit  
ordering is confusing in that representation, the TCP header is also shown in little-endian format.  
The actual data is fetched from memory in little-endian format.  
1
0
2
0
3
0
0
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6 7  
8
9
1
Source Port  
Destination Port  
Sequence Number  
Acknowledgement Number  
U
R
G K  
A
C
P
S
H
R
S
T
S
Y
N
F
I
N
TCP Header  
Length  
Reserved  
Window  
Checksum  
Urgent Pointer  
Options  
Figure 3-11. TCP Header (Traditional Representation)  
Byte3  
Byte2  
Byte1  
Byte0  
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7 6  
5
4
3
2
1
0
7
6
5
4
3
2
1
0
Destination Port  
Source Port  
LSB  
Sequence Number  
MSB  
Acknowledgement Number  
FI  
TCP  
Reserved  
U
R
G
A
C
K
P
S
H
R
S
T
S
Y
N
RE  
S
Window  
N
Header  
Length  
Urgent Pointer  
Checksum  
Options  
Figure 3-12. TCP Header (Little-Endian)  
The TCP header is always a multiple of 32 bit words. TCP options may occupy space at the end of  
the TCP header and are a multiple of 8 bits in length. All options are included in the checksum.  
The checksum also covers a 96-bit pseudo header conceptually prefixed to the TCP Header (see  
Figure 3-13 and Figure 3-14). The IPv4 pseudo header contains the IPv4 Source Address, the IPv4  
Destination Address, the IPv4 Protocol field, and TCP Length. The IPv6 pseudo header contains  
the IPv6 Source Address, the IPv6 Destination Address, the IPv6 Payload Length, and the IPv6  
Next Header field. Software pre-calculates the partial pseudo header sum, which includes IPv4 SA,  
DA and protocol types, but not the TCP length, and stores this value into the TCP checksum field  
of the packet.  
The Protocol ID field should always be added the least significant byte (LSB) of the 16 bit pseudo  
header sum, where the most significant byte (MSB) of the 16 bit sum is the byte that corresponds to  
the first checksum byte out on the wire.  
The TCP Length field is the TCP Header Length including option fields plus the data length in  
bytes, which is calculated by hardware on a frame by frame basis. The TCP Length does not count  
the 12 bytes of the pseudo header. The TCP length of the packet is determined by hardware as:  
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Receive and Transmit Description  
TCP Length = Payload + HDRLEN - TUCSS  
“Payload” is normally MSS except for the last packet where it represents the remainder of the  
payload.  
0
31  
IP Source Address  
IP Destination Address  
Layer 4 Protocol  
ID  
Zero  
TCP Length  
Figure 3-13. TCP Pseudo Header Content (Traditional Representation)  
IP Source Address  
IP Destination Address  
Upper Layer Packet Length  
Zero  
Next Header  
Figure 3-14. TCP PseudoHeader Content for IPv6  
Note: The IP Destination address is the final destination of the packet. Therefore, if a routing header is  
used, the last address in the route list is used in this calculation. The upper-layer packet length is  
the length of the TCP header and the TCP payload.  
The UDP header is always 8 bytes in size with no options.  
1
2
3
0
1
2
3
4
5
6
7
8
9
0
1 2  
3
4
5
6
7
8
9
0
1
2
3
4
5
6 7  
8
9
0
1
Source Port  
Length  
Destination Port  
Checksum  
Figure 3-15. UDP Header (Traditional Representation)  
Byte3  
Byte2  
Byte1  
Byte0  
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Destination Port  
Checksum  
Source Port  
Length  
Figure 3-16. UDP Header (Little-Endian Order)  
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Receive and Transmit Description  
UDP pseudo header has the same format as the TCP pseudo header. The IPv4 pseudo header  
conceptually prefixed to the UDP header contains the IPv4 source address, the IPv4 destination  
address, the IPv4 protocol field, and the UDP length (same as the TCP Length discussed above).  
The IPv6 pseudo header for UDP is the same as the IPv6 pseudo header for TCP. This checksum  
procedure is the same as is used in TCP.  
IP Source Address  
IP Destination Address  
Layer 4  
Zero  
UDP Length  
Protocol ID  
Figure 3-17. UDP Pseudo Header Diagram for IPv4  
IP Source Address  
IP Destination Address  
Upper Layer Packet Length  
Zero  
Next Header  
Figure 3-18. UDP PseudoHeader Diagram for IPv6  
Note: The IP Destination Address is the final destination of the packet. Therefore, if a routing header is  
used, the last address in the route list is used in this calculation. The upper-layer packet length is  
the length of the UDP header and UDP payload.  
Unlike the TCP checksum, the UDP checksum is optional. Software must set the TXSM bit in the  
TCP/IP Context Transmit Descriptor to indicate that a UDP checksum should be inserted.  
Hardware does not overwrite the UDP checksum unless the TXSM bit is set.  
3.5.8  
Transmit Checksum Offloading with TCP Segmentation  
The Ethernet controller supports checksum off-loading as a component of the TCP Segmentation  
offload feature and as a standalone capability. Section 3.5.8 describes the interface for controlling  
the checksum off-loading feature. This section describes the feature as it relates to TCP  
Segmentation.  
The Ethernet controller supports IP and TCP/UDP header options in the checksum computation for  
packets that are derived from the TCP Segmentation feature. The Ethernet controller is capable of  
computing one level of IP header checksum and one TCP/UDP header and payload checksum. In  
case of multiple IP headers, the driver has to compute all but one IP header checksum. The  
Ethernet controller calculates checksums on the fly on a frame by frame basis and inserts the result  
in the IP/TCP/UDP headers of each frame. TCP and UDP checksum are a result of performing the  
checksum on all bytes of the payload and the pseudo header.  
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Receive and Transmit Description  
Three specific types of checksum are supported by the hardware in the context of the TCP  
Segmentation offload feature:  
• IPv4 checksum (IPv6 does not have a checksum)  
• TCP checksum  
• UDP checksum  
Each packet that is sent via the TCP segmentation offload feature optionally includes the IPv4  
checksum and either the TCP or UDP checksum.  
All checksum calculations use a 16-bit wide one’s complement checksum. The checksum word is  
calculated on the outgoing data. The checksum field is written with the 16 bit one’s complement of  
the one’s complement sum of all 16-bit words in the range of CSS to CSE, including the checksum  
field itself.  
3.5.9  
IP/TCP/UDP Header Updating  
IP/TCP/UDP header is updated for each outgoing frame based on the IP/TCP header prototype  
which hardware transfers from the first descriptor(s) and stores on chip. The IP/TCP/UDP headers  
are fetched from host memory into an on-chip 240 byte header buffer once for each TCP  
segmentation context (for performance reasons, this header is not fetched again for each additional  
packet that is derived from the TCP segmentation process). The checksum fields and other header  
information are later updated on a frame by frame basis. The updating process is performed  
concurrently with the packet data fetch.  
The following sections define which fields are modified by hardware during the TCP Segmentation  
process by the Ethernet controller. Figure 3-19 illustrates the overall data flow.  
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Receive and Transmit Description  
PCI FIFO  
IP/TCP Header  
Packet Data  
Packet Data  
Header  
Update  
Checksum  
Calculation  
TX Packet FIFO  
Packet Data  
HOST Memory  
IP/TCP Header Buffer  
TCP Segmentation Data Flow  
Header processing  
Header processing  
Data Fetch Pause  
Packet Data Fetch Checksum Header  
Insertion  
Data Fetch Pause  
Checksum Header  
Insertion  
IP/TCP Header  
Prototy pe f etch  
Data Fetch  
resume  
Descriptors fetch  
Checksum  
Calculations  
Checksum  
Calculations  
Time  
Events Scheduling  
Figure 3-19. Overall Data Flow  
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Receive and Transmit Description  
3.5.9.1  
TCP/IP/UDP Header for the First Frame  
The hardware makes the following changes to the headers of the first packet that is derived from  
each TCP segmentation context.  
• IPv4 Header  
— IP Total Length = MSS + HDRLEN – IPCSS  
— IP Checksum  
— IPv6 Header  
— Payload Length = MSS + HDRLEN - IPCSS  
• TCP Header  
— Sequence Number: The value is the Sequence Number of the first TCP byte in this frame.  
— If FIN flag = 1b, it is cleared in the first frame.  
— If PSH flag =1b, it is cleared in the first frame.  
— TCP Checksum  
• UDP Header  
— UDP length: MSS + HDRLEN - TUCSS  
— UDP Checksum  
3.5.9.2  
TCP/IP/UDP Header for the Subsequent Frames  
The hardware makes the following changes to the headers for subsequent packets that are derived  
as part of a TCP segmentation context:  
Note: Number of bytes left for transmission = PAYLEN – (N * MSS). Where N is the number of frames  
that have been transmitted.  
• IPv4 Header  
— IP Identification: incremented from last value (wrap around)  
— IP Total Length = MSS + HDRLEN – IPCSS  
— IP Checksum  
• IPv6 Header  
• Payload Length = MSS + HRDLEN - IPCSS  
• TCP Header  
— Sequence Number update: Add previous TCP payload size to the previous sequence  
number value. This is equivalent to adding the MSS to the previous sequence number.  
— If FIN flag = 1b, it is cleared in these frames.  
— If PSH flag =1b, it is cleared in these frames.  
— TCP Checksum  
• UDP Header  
— UDP Length: MSS + HDRLEN – TUCSS  
— UDP Checksum  
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Receive and Transmit Description  
3.5.9.3  
TCP/IP/UDP Header for the Last Frame  
The controller makes the following changes to the headers for the last frame of a TCP  
segmentation context:  
Note: Last frame payload bytes = PAYLEN – (N * MSS)  
• IPv4 Header  
— IP Total Length = (last frame payload bytes + HDRLEN) – IPCSS  
— IP Identification: incremented from last value (wrap around)  
— IP Checksum  
• IPv6 Header  
• Payload Length = MSS + HDRLEN - IPCSS  
• TCP Header  
— Sequence Number update: Add previous TCP payload size to the previous sequence  
number value. This is equivalent to adding the MSS to the previous sequence number.  
— If FIN flag = 1b, set it in this last frame  
— If PSH flag =1b, set it in this last frame  
— TCP Checksum  
• UDP Header  
— UDP length: (last frame payload bytes + HDRLEN) - TUCSS  
— UDP Checksum  
3.6  
IP/TCP/UDP Transmit Checksum Offloading  
The previous section on TCP Segmentation offload describes the IP/TCP/UDP checksum  
offloading mechanism used in conjunction with TCP Segmentation. The same underlying  
mechanism can also be applied as a standalone feature. The main difference in normal packet mode  
(non-TCP Segmentation) is that only the checksum fields in the IP/TCP/UDP headers need to be  
updated.  
Before taking advantage of the Ethernet controller’s enhanced checksum offload capability, a  
checksum context must be initialized. For the normal transmit checksum offload feature, this task  
is performed by providing the Ethernet controller with a TCP/IP Context Descriptor with TSE = 0b  
to denote a non-segmentation context. For additional details on contexts, refer to Section 3.3.5.  
Enabling the checksum offloading capability without first initializing the appropriate checksum  
context leads to unpredictable results. Once the checksum context has been set, that context, is used  
for all normal packet transmissions until a new context is loaded. Also, since checksum insertion is  
controlled on a per packet basis, there is no need to clear/reset the context.  
The Ethernet controller is capable of performing two transmit checksum calculations. Typically,  
these would be used for TCP/IP and UDP/IP packet types, however, the mechanism is general  
enough to support other checksums as well. Each checksum operates independently and provides  
identical functionality. Only the IP checksum case is discussed as follows.  
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Receive and Transmit Description  
Three fields in the TCP/IP Context Descriptor set the context of the IP checksum offloading  
feature:  
• IPCSS  
This field specifies the byte offset form the start of the transferred data to the first byte to be  
included in the checksum. Setting this value to 0b means that the first byte of the data is  
included in the checksum. The maximum value for this field is 255. This is adequate for  
typical applications.  
Note: The IPCSS value needs to be less than the total DMA length to a packet. If this is not the case, the  
result will be unpredictable.  
• IPCSO  
This field specifies where the resulting checksum should be placed. Again, this is limited to  
the first 256 bytes of the packet and must be less than or equal to the total length of a given  
packet. If this is not the case, the checksum is not inserted.  
• IPCSE  
This field specifies where the checksum should stop. A 16-bit value supports checksum  
offloading of packets as large as 64KB. Setting the IPCSE field to all zeros means End-of-  
Packet. In this way, the length of the packet does not need to be calculated.  
As mentioned above, it is not necessary to set a new context for each new packet. In many cases,  
the same checksum context can be used for a majority of the packet stream. In this case, some of  
the offload feature only for a particular traffic type, thereby avoiding all context descriptors except  
for the initial one.  
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Receive and Transmit Description  
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PCI Local Bus Interface  
4
The PCI/PCI-X Family of Gigabit Ethernet Controllers are PCI 2.2 or 2.3 compliant devices and  
implement the PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0.  
Note: The 82540EP/EM, 82541xx, and 82547GI/EI do not support PCI-X mode.  
4.1  
PCI Configuration  
The PCI Specification requires implementation of PCI Configuration registers. After a system  
reset, these registers are initially configured by the BIOS, and/or a “Plug and Play” aware  
Operating System (OS). Device drivers read these registers to determine what resources (interrupt  
number, memory mapping location, etc.) the BIOS and/or OS assigned to the Ethernet controller.  
The 82547GI/EI uses a dedicated CSA port for its system bus connection. Logically, it still follows  
PCI configuration. However, some configuration parameters, such as cache line, are irrelevant.  
Additionally, the 82547GI/EI requires special interrupt configuration in the BIOS (see Section  
4.5).  
Note: The 82547GI/EI does not support 64-bit addressing.  
Four different regions of the PCI configuration space are used.  
Address  
00h-3Ch  
Item  
Description  
Section 2.3.1  
PCI  
DCh-E0h  
E4h-E8h  
F0h-FCh  
PCI Power Management  
PCI-X  
Section 6.3.3  
Section 4.1.1  
Section 4.1.3.1  
Message Signaled Interrupta  
a.  
Not applicable to the 82541xx and 82547GI/EI.  
These spaces are linked into a linked list using the Capabilities Pointer field (Cap_Ptr) in the PCI  
Configuration section.  
The implementation of the PCI registers for the PCI/PCI-X Family of Gigabit Ethernet Controllers  
are listed in Table 4-1:  
Table 4-1. Mandatory PCI Registers  
Byte Offset  
Byte 3  
Device ID  
Status Register  
Class Code (020000h)  
Byte 2  
Byte 1  
Vendor ID  
Command Register  
Revision ID  
Byte 0  
0h  
4h  
8h  
Header Type  
(00h)  
Latency  
Timer  
Cache Line  
Size  
Ch  
BIST (00h)  
10h  
4h  
Base Address 0a  
Base Address 1  
Base Address 2  
18h  
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PCI Local Bus Interface  
1Ch  
20h  
2h4  
28h  
2Ch  
30h  
34h  
38h  
Base Address 3 (unused)  
Base Address 4 (unused)  
Base Address 5 (unused)  
Cardbus CIS Pointer (not used)  
Subsystem ID  
Subsystem Vendor ID  
Expansion ROM Base Address  
Reserved  
Cap_Ptr  
Reserved  
Max_Latency  
(00h)  
Min_Grant  
(FFh)  
Interrupt Pin  
(01h)  
3Ch  
Interrupt Line  
a.  
Refer to Table 4-2.  
The following list provides explanations of the various PCI registers and their bit fields:  
Vendor ID  
Device ID  
This uniquely identifies all Intel PCI products. This field may be auto-loaded  
from the EEPROM at power on or upon the assertion of PCI_RST#. A value of  
8086h is the default for this field upon power up if the EEPROM does not  
respond or is not programmed.  
This uniquely identifies the Ethernet controller. This field may be autoloaded  
from the EEPROM at power on or upon the assertion of RST#. The default value  
for this field is used upon power up if the EEPROM does not respond or is not  
programmed.  
Command Reg. The layout is listed in Table 4-3. Shaded bits are not used by this implementation  
and are hard wired to 0b.  
Status Register The layout is listed in Table 4-4. Shaded bits are not used by this implementation  
and are hard wired to 0b.  
Revision  
Sequential stepping number starting with 00h for the A0 revision of the Ethernet  
controller. Refer to the PCI/PCI-X Family of Gigabit Ethernet Controllers  
Specification Update for the latest stepping information.  
Class Code  
The class code, 020000h identifies the Ethernet controller as an Ethernet adapter.  
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PCI Local Bus Interface  
1
Cache Line Size Used to store the cache line size. The value is in units of 4 bytes. A system with a  
cache line size of 64 bytes sets the value of this register to 10h. The only sizes  
that are supported are 16, 32, 64, and 128 bytes. All other sizes are treated as 0b.  
See the information about exceptions in Section 4.4.  
Unsupported values affect PCI cache line support. All writes default to using the  
memory write (MW) command, and memory read command determination uses  
a cache line size of 32 bytes.  
Latency Timer The lower two bits are not implemented and return 0b. The upper six bits are  
Read/Write.  
Header Type  
BIST  
This is for a normal single function Ethernet controller and reads 00h.  
Built in Self-test is not implemented as supportable from PCI configuration  
space in this version of the Ethernet controller.  
Base Address Registers  
The Base Address Registers (or BARs) are used to map the Ethernet con-  
troller’s register space and flash to system memory space. In PCI-X mode  
or in PCI mode when the BAR32 bit of the EEPROM is 0b, two registers  
are used for each of the register space and the flash memory in order to  
map 64-bit addresses. In PCI mode, if the BAR32 bit in the EEPROM is  
1b, one register is used for each to map 32-bit addresses.  
64-bit BARs  
PCI-X mode with BAR32 bit in the EEPROM set to 0b.  
Table 4-2. Base Address Registers  
BAR Addr.  
31 4  
3
2
1
0
Memory Register Base Address (bits  
31:4)  
pref.  
type  
mem  
0
1
2
10h  
14h  
18h  
Memory Register Base Address (bits 63:32)  
Memory Flash Base Address (bits  
31:4)  
pref.  
type  
0b  
mem  
mem  
3
4
5
1Ch  
20h  
24h  
Memory Flash Base Address (bits 63:32)  
IO Register Base Address (bits 31:2)  
Reserved (read as all 0b’s)  
32-bit BARs  
Conventional PCI mode with BAR32 bit in the EEPROM set to 1b  
BAR Addr.  
31  
4
3
2
1
0
0
1
2
3
4
5
10h  
14h  
18h  
1Ch  
20h  
24h  
Memory Register Base Address  
Memory Flash Base Address  
pref.  
pref.  
type  
mem  
mem  
mem  
type  
0b  
IO Register Base Address (bits 31:2)  
Reserved (read as all 0b’s)  
Reserved (read as all 0b’s)  
Reserved (read as all 0b’s)  
1. Not applicable to the 82547GI/EI.  
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PCI Local Bus Interface  
All base address registers have the following fields:  
Read/  
Write  
Initial  
Value  
Field  
Bit(s)  
Description  
0b for  
mem  
0b indicates memory space. 1b indicates I/O.  
Mem  
0
R
1b for I/O  
00b for 32-  
bit  
Indicates the address space size.  
00b = 32-bit  
Type  
2:1  
3
R
R
10b for 64-  
bit  
10b = 64-bit  
0b = non-prefetchable space  
1b = prefetchable space  
Prefetch  
0b  
Ethernet controller implements non-prefetchable space  
since it has read side-effects.  
The lower bits of the address are hard-wired to 0b. The  
upper bits can be written by the system software to set  
the base address of the register or flash address space.  
The memory register space is 128K bytes. The  
Memory Register BAR has:  
•
•
Bits 16:4 are hard-wired to 0b.  
Bits 63:17 or 31:17 are read/write.  
The size of the flash space can very between 64 KB and  
512 KB depending on the FLASH size read from the  
EEPROM. The Memory Flash BAR has these  
characteristics:  
Address  
31:0  
R/W  
0b  
Flash Size Valid Bits Zero Bits  
(R/W) (RO)  
•
•
•
•
64 KB 63/31:16 15:4  
128 KB 63/31:17 16:4  
256 KB 63/31:18 17:4  
512 KB 63/31:19 18:4  
The size of the IO register space is 8 bytes. The I/O  
Register BAR has:  
•
•
Bit 2 hard-wired to 0b  
Bits 31:3 as read/write  
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PCI Local Bus Interface  
Expansion ROM Base Address  
This register is used to define the address and size information for boot-  
time access to the optional Flash memory.  
31  
11  
10  
1
0
Expansion Rom Base Address  
Reserved  
En  
Read/  
Write  
Initial  
Value  
Field  
Bit(s)  
Description  
1b = Enables expansion ROM access.  
0b = Disables expansion ROM access.  
En  
Reserved  
0
R/W  
R
0b  
0b  
10:1  
Always read as 0b. Writes are ignored.  
The lower bits of the address are hard-wired to 0b.  
The upper bits can be written by the system software  
to set the base address of the register or flash  
address space.  
Since the flash is used as the expansion ROM, the  
size of the expansion ROM can very between 64 KB  
and 512 KB, depending on the FLASH size read  
from the EEPROM.  
Address  
31:11  
R/W  
0b  
Flash Size Valid Bits Zero Bits:  
•
•
•
•
64 KB 63/31:16 15:11  
128 KB 63/31:17 16:11  
256 KB 63/31:18 17:11  
512 KB 63/31:19 18:11  
CardBus CIS Pointer (82541PI/GI/EI and 82540EP Only)  
When the Enable CLK_RUN# bit of the EEPROM’s Initialization Control  
Word 2 and the 64/32 BAR bit of the EEPROM Initialization Control  
Word 1 (indicating a 32-bit BAR) are both set to 1b, the Cardbus CIS  
Pointer contains a value of 00000022h. Otherwise, it contains a value of  
00000000h.  
31  
3
2
0
Offset  
Space  
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Read/  
Write  
Initial  
Value  
Field  
Bit(s)  
Description  
Indicates the address space where the CIS is  
located.  
0 = Configuration Space  
1 = BAR0  
2 = BAR1  
Space  
2:0  
R/W  
0 or 2  
3 = BAR2  
4 = BAR3  
5 = BAR4  
6 = BAR5  
7 = Expansion ROM  
Offset within the specified address space,  
multiplied by eight. When enabled, the value  
indicates that the CIS (Card Information  
Structure) is at an offset of 4*8, or 32 bytes into  
the Flash memory.  
Offset  
31:3  
R
0 or 4  
Subsystem ID  
This value can be loaded automatically from the EEPROM upon power-up or  
PCI reset. A value of 1008h is the default for this field upon power-up if the  
EEPROM does not respond or is not programmed.  
Subsystem Vendor ID  
This value can be loaded automatically from the EEPROM upon power-up or  
PCI reset. A value of 8086h is the default for this field upon power-up if the  
EEPROM does not respond or is not programmed.  
Cap_Ptr  
The Capabilities Pointer field (Cap_Ptr) is an 8-bit field that provides an offset in  
the Ethernet controller’s PCI Configuration Space for the location of the first  
item in the Capabilities Linked List. The Ethernet controller sets this bit and then  
implements a capabilities list to indicate that it supports PCI Power  
1
Management, PCI-X, and Message Signaled Interrupts . Its value is DCh which  
2
is the address of the first entry: ACPI Power Management.  
Address  
DCh-E0h  
Item  
Next Pointer  
E4h  
ACPI Power Management  
PCI-X  
E4h-E8h  
F0h-FCh  
F0h  
00h  
Message Signaled Interrupt  
Figure 4-1. Capabilities Linked List  
In conventional PCI mode, Message Signaled interrupts can be disabled in the  
EEPROM. If disabled, the message signaled interrupts won’t appear on the  
linked list and PCI-X’s “Next Pointer” is 0b.  
1. Not applicable to the 82541xx or 82547GI/EI.  
2. Not applicable to the 82541ER.  
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PCI Local Bus Interface  
1
Max_Lat/Min_Gnt  
The Ethernet controller places a very high load on the PCI bus during peak  
transmit and receive traffic. In full duplex mode, it has a peak throughput  
demand of 250 MB/sec. The peak delivered bandwidth on a 64-bit PCI bus at 33  
MHz is 264 MB/sec, so the bus is fully saturated when transmit and receive are  
operating simultaneously. In half duplex operation, the Ethernet controller has a  
peak throughput demand of 125 MB/sec, which still puts an enormous load on  
the PCI bus. Consequently, the Max_Lat should be small and is set to 00h, and  
Min_Gnt is set to FFh indicating that the Ethernet controller requires a very high  
priority and time slice.  
Interrupt Pin  
Read only register indicating which interrupt line (INTA# vs. INTB#) the  
82546GB/EB uses. A value of 1b indicates that the 82546GB/EB uses INTA#  
(as with all single-port Ethernet controllers). A value of 10b indicates that the  
82546GB/EB uses INTB#.  
For each separate device/function within the Ethernet controller, the value  
reported here is based on the EEPROM Initialization Control Word 3 associated  
with this controller, as well as whether both device/functions are enabled.  
Provided both functions are enabled, then the value reported for each specific  
function is based on the Interrupt Pin field of each Ethernet controller’s  
Initialization Control Word 3.  
If only a single internal device/function is enabled, then the value reported here  
is 1b regardless of EEPROM configuration.  
Interrupt Line  
Read write register programmed by software to indicate which of the system  
interrupt request lines this Ethernet controller’s interrupt pin is bound to. See the  
PCI definition for more details.  
Table 4-3. Command Register Layout  
15  
10 9  
0
Reserved  
Command Bits  
Bit(s)  
Initial Value  
Description  
0
1
0b  
0b  
I/O Access Enable.  
Memory Access Enable.  
Enable Mastering. Ethernet controller in PCI-X  
mode is permitted to initiate a split completion  
transaction regardless of the state of this bit.  
2
3
0b  
0b  
Special Cycle Monitoring.  
1. This bit is a don’t care for the 82547GI/EI.  
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Bit(s)  
Initial Value  
Description  
Memory Write and Invalidate Enable (not  
applicable to the 82547GI/EI).  
4
5
6
0b  
0b  
0b  
Palette Snoop Enable.  
Parity Error Response (not applicable to the  
82547GI/EI).  
7
8
0b  
0b  
0b  
0b  
Wait Cycle Enable.  
SERR# Enable (not applicable to the 82547GI/EI).  
Fast Back-to-Back Enable.  
9
10a  
Interrupt Disable (INTA# or CSA signaled).  
15:10  
15:11a  
0b  
Reserved.  
a.  
82541xx and 82547GI/EI only.  
Table 4-4. Status Register Layout  
15  
4 3  
0
Status Bits  
Reserved  
Bit(s)  
Initial Value  
Description  
3:0  
2:0a  
0b  
0b  
Reserved.  
Interrupt Status. This bit is 1b when the Ethernet  
controller is generating an interrupt internally.  
When Interrupt Disable in the Command Register  
is also cleared, the Ethernet controller asserts  
INTA# or signal an interrupt over CSA.  
3a  
New Capabilities: Indicates that an Ethernet  
controller implements Extended Capabilities. The  
Ethernet controller sets this bit and implements a  
capabilities list to indicate that it supports PCI  
Power Management, PCI-X Bus, and message  
signaled interrupts.  
4
1b  
5
6
1b  
0b  
66 MHz Capable (don’t care for the 82547GI/EI).  
UDF Supported. Hardwired to 0b for PCI 2.3a.  
Fast Back-to-Back CapableThis bit must be  
cleared to 0b in PCI-X mode (not applicable to the  
82547GI/EI).  
7
0b  
8
0b  
01b  
0b  
Data Parity Reported.  
DEVSEL Timing (indicates medium device). Not  
applicable to the 82547GI/EI.  
10:9  
11  
Signaled Target Abort.  
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PCI Local Bus Interface  
Bit(s)  
12  
Initial Value  
Description  
Received Target Abort.  
0b  
0b  
13  
Received Master Abort.  
Signaled System Error (not applicable to the  
82547GI/EI).  
14  
15  
0b  
0b  
Detected Parity Error (not applicable to the  
82547GI/EI).  
a.  
82541xx and 82547GI/EI only.  
4.1.1  
PCI-X Configuration Registers  
The Ethernet controller supports additional configuration registers that are specific to PCI-X.  
These registers are visible in conventional PCI and PCI-X modes, although they only affect the  
operation of PCI-X mode. The PCI-X registers are linked into the Capabilities linked list.  
Note: The 82540EP/EM, 82541xx, and 82547GI/EI do not support PCI-X mode.  
Byte Offset  
Byte 3  
Byte 2  
Byte 1  
Byte 0  
E4h  
E8h  
PCI-X Command  
Next Capability  
PCI-X Capability ID  
PCI-X Status  
Figure 4-2. PCI-X Capability Registers  
PCI-X Capability ID  
4.1.1.1  
4.1.1.2  
Read/  
Write  
Initial  
Value  
Bits  
Description  
Capability ID - Identifies the PCI-X register set in the capabilities  
linked list.  
7:0  
R
7
Next Capability  
Read/  
Write  
Initial  
Value  
Bits  
Description  
Next Capability – points to the next capability in the capabilities  
linked list.  
7:0  
R
F0a  
a.  
In conventional PCI mode, Message Signaled Interrupts can also be disabled in the EEPROM. If disabled, the Message  
Signaled Interrupt registers are not visible, and PCI-X’s “Next Capability” pointer is 0b.  
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PCI Local Bus Interface  
4.1.1.3  
PCI-X Command  
15  
7
6
4
3
2
1
0
Max. Split Trans-  
actions  
Read  
Count  
Reserved  
RO  
DP  
Read  
Write  
Initial  
Value  
Bits  
Description  
Data Parity Error Recovery Enable. If this bit is 1b, the Ethernet  
controller attempts to recover from Parity errors. If this bit is 0b, the  
Ethernet controller asserts SERR# (if enabled) whenever the Master  
Data Parity Error bit (Status Register, bit 8) is set.  
0
1
RW  
0b  
1b  
Enable Relaxed Ordering. If this bit is set, the Ethernet controller sets  
the Relaxed Ordering attribute bit in some transactions.  
RW  
Maximum Memory Read Byte Count. This register sets the  
maximum byte count the Ethernet controller uses for a Memory Read  
Sequence. The allowable values are:  
Register  
Maximum Byte Count  
3:2  
RW  
0b  
0
1
2
3
512  
1024  
2048  
4096  
Maximum Outstanding Split Transactions. This register sets the  
maximum number of outstanding split transactions that the Ethernet  
controller uses. The Ethernet controller is only allowed to have one  
outstanding split transaction at any time.  
Register  
Maximum Outstanding Transactions  
0
1
2
3
4
5
6
7
1
2
6:4  
RW  
0b  
3
4
8
12  
16  
32  
15:7  
R
0b  
Reserved. Reads as 0b  
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4.1.1.4  
PCI-X Status  
31 29 28 26 25 23 22 21  
20  
19  
18  
17  
16 15  
8
7
3
2
0
Read Max.  
Size Split  
Rd  
Byte  
Device  
Number  
Func.  
Num.  
Res.  
Cplx USC SCD 133 64b  
Bus Number  
Read/  
Write  
Intial  
Value  
Bits  
Description  
Function Number. This number forms part of the Requester and  
Completer IDs for PCI-X transactions.  
2:0  
R
R
0b  
Device Number. The system assigns a device number (other than 0b) to  
the Ethernet controller. It forms part of the Requester and Completer IDs  
for PCI-X transactions. The Ethernet controller updates this register with  
the contents of AD[15:11] on any Type 0 Configuration Write cycle.  
7:3  
1Fh  
Bus Number. This indicates the bus the Ethernet controller is placed on. It  
forms part of the Requester and Completer IDs for PCI-X transactions. The  
Ethernet controller updates this register with the contents of AD[7:0] on any  
Type 0 Configuration Write cycle.  
15:8  
16  
R
R
R
FFh  
1ba  
1ba  
0b  
64-bit Device. This indicates the Ethernet controller is a 64-bit device. It  
does not indicate the current bus width. It is loaded from the EEPROM  
Initialization Control Word 2 (see Section 5.6.12).  
133 MHz Capable. A 1b indicates that the Ethernet controller is capable of  
operating at 133 MHz in PCI-X mode. A 0b indicates 66 MHz capability.  
This bit is loaded from the EEPROM Initialization Control Word 2 (see  
Section 5.6.12).  
17  
Split Completion Discarded. (Write 1b to clear) This bit is set if the  
Ethernet controller discards a Split Completion because the requester  
would not accept it.  
read, write 1b  
to clear  
18  
Unexpected Split Completion. (Write 1b to clear) This bit indicates  
whether the Ethernet controller received an unexpected Split Completion  
with its requestor ID.  
read, write 1b  
to clear  
19  
20  
0b  
0b  
Device Complexity. A 0b indicates the Ethernet controller is a simple  
device. A 1b indicates that the Ethernet controller is a bridge.  
R
Designed Maximum Memory Read Byte Count. Indicates the maximum  
memory read byte count the Ethernet controller is designed to generate.  
Register  
Maximum Byte Count  
0
1
2
3
512  
1024  
2048  
4096  
22:21  
R
2ba  
The value of this register depends on the Max_Read bit in the EEPROM’s  
Initialization Control Word 2 (see Section 5.6.12).  
Max_Read = 0b then value = 2 (2 KB)  
Max_Read = 1b then value = 3 (4 KB)  
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Read/  
Write  
Intial  
Value  
Bits  
Description  
Designed Maximum Outstanding Split Transactions. A 0b indicates that  
the Ethernet controller is designed to have at the most one outstanding  
transaction.  
Register  
Maximum Outstanding Transactions  
0
1
2
3
4
5
6
7
1
2
25:23  
R
0b  
3
4
8
12  
16  
32  
Designed Maximum Cumulative Read Size. Indicates a number that is  
greater or equal maximum cumulative outstanding bytes to be read at one  
time.  
Register  
Maximum Outstanding Bytes  
0
1
2
3
4
5
6
7
1 KB  
2 KB  
4 KB  
8 KB  
16 KB  
32 KB  
64KB  
128 KB  
28:26  
R
The value of this register depends on the DMCR_Map and Max_Read bits  
in the EEPROM’s Initialization Control Word 2 (see Section 5.6.12).  
•
DMCR_Map = 0b:  
The value of this register reflects the number of bytes programmed in the  
Maximum Memory Read Byte Count (MMRBC) field of the PCI-X  
Command Register as follows:  
•
•
•
•
•
•
MMRBC = 0 (512) - DMCRS = 0 (1KB)  
MMRBC = 1 (1K) - DMCRS = 0 (1KB)  
MMRBC = 2 (2K) - DMCRS = 1 (2KB)  
MMRBC = 3 (4K) - DMCRS = 2 (4KB)  
DMCR_Map = 1b and Max_Read = 0b: DMCRS = 1 (2KB)  
DMCR_Map = 1b and Max_Read = 1b: DMCRS = 2 (4KB)  
Received Split Completion Error Message. This bit is set if the Ethernet  
controller receives a Split Completion Message with the Split Completion  
Error attribute bit set.  
Read, write 1b  
to clear  
29  
0b  
0b  
31:30  
R
Reserved. Reads as 0b  
a. Loaded from EEPROM.  
4.1.2  
Reserved and Undefined Addresses  
Any PCI or PCI-X register address space not explicitly declared in this specification should be  
considered to be reserved, and should not be written. Writing to reserved or undefined  
configuration register addresses can cause indeterminate behavior. Reads from reserved or  
undefined configuration register addresses can return indeterminate values.  
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PCI Local Bus Interface  
1
4.1.3  
Message Signaled Interrupts  
Message Signaled Interrupt (MSI) capability is optional for PCI 2.2 or 2.3, but required for PCI-X.  
When Message Signaled Interrupts are enabled, instead of asserting an interrupt pin, the Ethernet  
controller generates an interrupt using a memory write command. The address and most of the data  
of the command are determined by the system and programmed in configuration registers. This  
permits the system to program a different message for each function so it can speed up interrupt  
delivery.  
To enable Message Signaled Interrupts, the system software writes to the “MSI Enable” bit in the  
MSI “Message Control” register. When Message Signaled Interrupts are enabled, the Ethernet  
controller no longer asserts its INTA# pin to signal interrupts.  
MSI systems allow a function to request up to 32 messages, but does not guarantee that all of them  
are allocated. The Ethernet controller supports only a single message. When Message Signaled  
Interrupts are enabled, the Ethernet controller generates a message when any of the unmasked bits  
in the Interrupt Cause Read register (ICR) are set to 1b. The Ethernet controller does not generate  
the message again until the ICR is read and a subsequent interrupt event occurs.  
In conventional PCI mode, Message Signaled Interrupts can also be disabled in the EEPROM. If  
MSI is disabled, the Message Signaled Interrupt registers is not visible.  
4.1.3.1  
Message Signaled Interrupt Configuration Registers  
Byte Offset  
Byte 3  
Byte 2  
Byte 1  
Byte 0  
MSI  
Capability ID  
F0h  
Message Control  
Next Capability  
F4h  
F8h  
FCh  
Message Address  
Message Upper Address  
Reserved  
Message Data  
Figure 4-3. Message Signaled Interrupt Configuration Registers  
MSI Capability ID  
4.1.3.1.1  
Read/  
Write  
Initial  
Value  
Bits  
Description  
Capability ID - Identifies the Message Signaled Interrupt register set in  
the capabilities linked list.  
7:0  
R
05h  
4.1.3.1.2  
Next Capability  
Read/  
Write  
Initial  
Value  
Bits  
Description  
Next Capability – points to the next capability in the capabilities  
linked list. Its value is 0b since the Message Signaled Interrupt is the  
last item in the list.  
7:0  
R
00h  
1. Not applicable to the 82541xx or 82547GI/EI.  
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4.1.3.1.3  
Message Control  
15  
8
7
6
4
3
1
0
Multiple  
Enable  
Multiple  
Capable  
Reserved  
64b  
En  
Read/  
Write  
Initial  
Value  
Bits  
Description  
MSI Enable. If 1b, Message Signaled Interruptsa are enabled and the  
Ethernet controller generates Message Signaled Interrupts instead of  
asserting INTA#.  
0
R
0b  
Multiple Message Capable. Indicates the number of messages  
requested. The Ethernet controller only requests one message.  
Register  
Number of messages  
0
1
2
3
4
5
6
7
1
2
4
8
3:1  
R
0b  
16  
32  
Reserved  
Reserved  
Multiple Message Enable. Written by the system to indicate the  
number of messages allocated. Since the Ethernet controller only  
supports one message, the system should never write a value other  
than 0b.  
6:4  
RW  
0b  
64-bit capable. A value of 1b indicates that the Ethernet controller is  
capable of generating 64-bit message addresses.  
7
R
R
1b  
0b  
15:8  
Reserved. Reads as 0b.  
a.  
Not applicable to the 82541xx or 82547GI/EI.  
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4.1.3.1.4  
Message Address  
Read/  
Write  
Initial  
Value  
Bits  
Bits  
Bits  
Description  
Message Address – Written by the system to indicate the lower 32-  
bits of the address to use for the MSI memory write transaction. The  
lower two bits are always written as 0b.  
31:0  
RW  
0b  
4.1.3.1.5  
Message Upper Address  
Read/  
Write  
Initial  
Value  
Description  
Message Upper Address – Written by the system to indicate the  
upper 32-bits of the address to use for the MSI memory write  
transaction.  
31:0  
RW  
0b  
4.1.3.1.6  
Message Data  
Read/  
Write  
Initial  
Value  
Description  
Message Data – Written by the system to indicate the lower 16 bits of  
the data written in the MSI memory write DWORD transaction. The  
upper 16 bits of the transaction are written as 0b.  
15:0  
RW  
0b  
4.2  
Commands  
The Ethernet controller is capable of decoding and encoding commands for both PCI and PCI-X  
modes. The difference between PCI and PCI-X commands is noted in Table 4-5.  
Table 4-5. PCI and PCI-X Encoding Difference  
C/BE  
PCI Commands  
Encoding  
Abr.  
PCI-X Commands  
Abr.  
0h  
1h  
2h  
3h  
4h  
5h  
6h  
7h  
8h  
9h  
Ah  
Bh  
Ch  
Interrupt Acknowledge  
Special Cycle  
I/O Read  
Interrupt Acknowledge  
Special Cycle  
I/O Read  
IOR  
IOR  
I/O Write  
IOW  
I/O Write  
IOW  
Reserved  
Reserved  
Reserved  
Reserved  
Memory Read  
Memory Write  
Reserved  
MR  
Memory Read DWORD  
MRD  
MW  
Alias to MRB  
AMR  
AMW  
CFR  
CFW  
SC  
Reserved  
Alias to MWB  
Configuration Read  
Configuration Write  
Memory Read Multiple  
CFR  
CFW  
MRM  
Configuration Read  
Configuration Write  
Split Completion  
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PCI Local Bus Interface  
Table 4-5. PCI and PCI-X Encoding Difference  
C/BE  
PCI Commands  
Encoding  
Abr.  
DAC  
PCI-X Commands  
Dual Address Cycle  
Abr.  
DAC  
Dh  
Eh  
Fh  
Dual Address Cycle  
Memory Read Line  
MRL  
MWI  
Memory Read Block  
Memory Write Block  
MRB  
MWB  
Memory Write & Invalidate  
As a target, the Ethernet controller only accepts transactions that address its BARs or a  
configuration transaction in which its IDSEL input is asserted. In PCI-X mode, the Ethernet  
controller also accepts split completion for an outstanding memory read command that it has  
requested. The Ethernet controller does not respond to Interrupt Acknowledge or Special Cycle in  
either mode.  
Table 4-6. Accepted PCI/PCI-X Command as a Target  
Transaction Target  
PCI Commands  
PCI-X Commands  
Register or Flash Read  
Register or Flash Write  
Configuration Read  
MR,MRL,MRM,IOR  
MRD, MRB, AMR,IOR  
MW, MWI,IOW  
CFR  
MW, MWB, AMW,IOW  
CFR  
CFW  
SC  
Configuration Write  
CFW  
Memory Read Completion  
N/A  
As a master, the Ethernet controller generates Read and Write commands for different causes as  
listed in Table 4-7. The addresses of these transactions are programmed either by system software  
or the software driver. The Ethernet controller always expects that they are claimed by one of the  
devices on the bus segment. The Ethernet controller never generates Interrupt Acknowledge,  
Special Cycle, I/O commands, or Configuration Commands.  
Table 4-7. Generated PCI/PCI-X as a Master  
Transaction Cause  
PCI Commands  
PCI-X Commands  
CMD  
RO  
Tx Descriptor Read  
Tx Descriptor Write back  
Tx Data Read  
MR,MRL,MRM  
MW,MWI  
MRB  
MWB  
MRB  
MRB  
MWB  
MWB  
MWB  
SC  
1
0
MR, MRL,MRM  
MR,MRL,MRM  
MW,MWI  
1
Rx Descriptor Read  
Rx Descriptor Write back  
Rx Data Write  
1
0
MW,MWI  
1
Message Signaled Interrupta  
MW  
0
Split Completion  
N/A  
N/A  
a.  
Not applicable to the 82541xx or 82547GI/EI.  
Transaction burst length on PCI is determined by several factors, including the PCI latency timer  
expiration, the type of bus transfer (descriptor read/write or data read/write) made, the size of the  
data transfer (for data transfers), and whether the cycle is initiated by the receive or transmit logic.  
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Following are a few specific rules:  
• For descriptor fetches, the burst length is always equal to the multiple of cache line sizes set by  
the transmit and receive descriptor fetch threshold fields. (See Section 3.2.4 and Section 3.4.1)  
For descriptor writes, the transfer size ranges from 8 bytes to N cache line's worth of data.  
Cache line sizes are: 16, 32, 64, and 128 bytes.  
• For transmit data fetches, the burst length is generally equal to the block of data being fetched,  
in other words, a descriptor's worth of data.  
• For receive data writes, the burst size is typically equal to the packet length (rounded up to the  
next 8 bytes) or the buffer size, whichever is smaller.  
4.3  
PCI/PCI-X Command Usage  
The Ethernet controller optimizes the use of PCI/PCI-X bus cycles to maximize throughput. The  
following sections describe this behavior.  
4.3.1  
Memory Write Operations  
Memory write command usage has been implemented in the Ethernet controller to improve PCI  
performance. As noted below, cache line size has a significant impact on the usage of memory  
write commands. Specifically, cache line size entries which are unsupported causes hardware to  
default to the Memory Write (MW) command for all master write transactions. Also, all writes  
default to MW if the Memory Write and Invalidate (MWI) enable bit in the PCI configuration  
command register is 0b. MWI is the preferred write command and is used when the circumstances  
allow it.  
Figure 4-4 depicts a behavioral state-machine representation of the command usage algorithm for  
master write operations.  
Upon EACH master write access, the hardware evaluates the address alignment and the amount of  
data to be transferred. The following guidelines are used for command determination:  
• If the address is cache line aligned and there is at least one cache line of data, then hardware  
uses the MWI command.  
• If the address is aligned but there is not at least one cache line of data, or the address is not  
aligned, or if the MWI enable bit is set to 0b, then hardware uses the MW command.  
During the burst, regardless of which command was originally issued, the hardware evaluates the  
remaining amount of data each time the write burst comes to a cache line boundary, or when the  
transaction is terminated due to a target disconnect or latency timer expiration.  
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IDLE  
Wr_Req || (Cnt_Rmn != 0)  
Write Command  
Determination  
!Aligned || (Aligned && (Count < CLS)) || !MWI_Enable  
Aligned && (Count >= CLS)  
MWI  
Burst*  
MW  
Burst  
Cnt_Rmn = 0  
Cnt_Rmn = 0  
Terminate  
Transaction  
Boundary || Terminate  
MWI_Enable &&  
d && Cnt_Rmn >= CLS)  
Terminate  
!MWI_Enable ||  
(!Aligned || Cnt_Rmn < CLS)  
MWI  
Boundary  
Evaluation  
Count = Amount of data for XFR  
Cnt_Rmn = Remaining data for XFR  
Wr_Req = Initial request for master write  
CLS = Cache line size  
Boundary = At cache line boundary?  
Aligned = Address aligned to cache line boundary  
Terminate = Target disconnect or latency timer ex  
* Either the initiation or continuation of the MWI Burst  
Figure 4-4. Master Write Command Usage Algorithm  
4.3.1.1  
MWI Bursts  
• If there is at least one cache line of data remaining, then the Ethernet controller continues the  
MWI burst.  
• If there is not at least one cache line of data remaining, then the Ethernet controller terminates  
the transaction on the boundary, re-acquires the bus, and issues a MW command for the  
remainder of data.  
• If the transaction is terminated prematurely due to a target disconnect or latency time-out, the  
Ethernet controller re-evaluates command usage based on the new start address and the  
amount of remaining data.  
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4.3.1.2  
MW Bursts  
• The Ethernet controller always continues the burst until the end. If the system is concerned  
about MWI usage, it disconnects at the cache line boundary. The Ethernet controller then  
restarts the transaction and re-evaluates command usage.  
Note: The algorithm described above defaults to the MW case when the MWI enable bit in the  
Configuration Register is set to 0b.  
4.3.2  
Memory Read Operations  
For all read commands, the hardware evaluates the amount of data to be read with respect to the  
cache line size register and the read address alignment for command determination. The following  
rules apply:  
Table 4-8. Rules for Memory Read Operations  
Amount of  
Number of Cache Line  
Command  
Data Requested  
Boundaries Crossed  
Used by Hardware  
> 2 Cache Lines  
>= 1 Cache Line  
<= 1 Cache Line  
< 1 Cache Line  
n/a  
>= 2  
0 or 1  
0
MRM  
MRM  
MRL  
MR  
In other words, read command usage depends on the number of cache lines from which the data  
must be read from the target device.  
As mentioned above, unsupported values in the cache line size field default to a size of 32 bytes for  
the memory read command usage algorithm.  
Note: MRL should be used for a single cache line of data that is cache line aligned.  
4.3.2.1  
PCI-X Command Usage  
In PCI-X mode, the Ethernet controller takes advantage of split transaction protocol to minimize  
retries and eliminate delayed read transactions.  
Target Split Responses  
When the Ethernet controller responds to a Memory Read or I/O Read command it determines if  
the data can be returned within 16 clock cycles. If not, it signals a split response and returns data  
later through the split completion protocol. If the Ethernet controller already has a command in its  
completion register it retries the requested read until the register is empty. Target posted writes and  
split completion are still accepted during that period. The internal register reads that cause splits  
are:  
• General Registers: CTRL, STATUS, EECD, CTRL_EXT, FCAL, FCAH, FCT, VET, FCTTV,  
TXCW, RXCW, PBA,  
• Interrupt Registers: ICR, ICS, IMS, IMC  
• Transmit Registers: TCTL  
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Outstanding Memory Read  
When the Ethernet controller masters a memory read and is responded to with a split response it  
waits for the completion of the data as a target. The Ethernet controller allows one outstanding  
memory read command at any time. The Ethernet controller continues to master posted memory  
writes and split completions if there are any.  
Relaxed Ordering  
• The Ethernet controller takes advantage of the relaxed ordering rules in PCI-X. By setting the  
RO bit for some of its master transactions, the Ethernet controller allows the system to  
optimize performance in the following cases:  
— Relaxed ordering for descriptor and data reads: When the Ethernet controller masters a  
read transaction its split completion has no relationship with the writes from the CPUs  
(same direction). It should be allowed to bypass the writes from the CPUs.  
— Relaxed ordering for receiving data writes: When the Ethernet controller masters receive  
data writes it also allows them to bypass each other in the path to system memory because  
the software does not process this data until their associated descriptor writes are done.  
• The Ethernet controller cannot relax ordering for descriptor writes or an MSI write.  
No Snoop Setting  
The Ethernet controller always clears this bit in all of its master transactions because it cannot  
guarantee that the memory locations between transaction addresses are not cached in the system.  
1
4.4  
Cache Line Information  
The cache line size PCI configuration register is programmed by the BIOS and/or OS after a  
system reset. The value in the cache line size register corresponds to the cache line size that the  
system supports.  
The value programmed into the cache line size register affects the DMA operations of the Ethernet  
controller. In general, the hardware attempts to fetch descriptors on a cache line basis. It also  
attempts to write back descriptors when a cache line of descriptors has been filled.  
The size of the cache line register also has an effect on the Ethernet controller’s usage of the MWI  
PCI command, because the use of this command requires that at least a whole cache line of data is  
written. The memory read commands are also affected as discussed in Section 4.3.2.  
In PCI-X mode, the cache line size does not affect the commands used. However it does affect the  
descriptor transfer. If an unsupported cache line size larger than 128 bytes is programmed, the  
Ethernet controller acts as if a cache line size of 128 bytes was programmed.  
1. Not applicable to the 82547GI/EI.  
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4.4.1  
Target Transaction Termination  
When the Ethernet controller accepts a transaction as a target it always disconnects the transaction  
after a single data phase by following the “Master Completion Termination” in PCI 2.2, 2.3, or  
“Single data phase disconnect termination” in PCI-X. The “memory” in the Ethernet controller is  
actually a set of registers and is marked as “non-prefetchable”. This is also the case for FLASH  
memory.  
4.5  
Interrupt Assignment (82547GI/EI Only)  
During a Power-On Self-Test (POST), the system BIOS must assign an Interrupt Request (IRQ) for  
the 82547GI(EI). The 82547GI(EI) generates an interrupt by sending a hub interface message  
through the CSA port.  
In a typical system, the 82547GI(EI) component is Device 1 on the bus behind the CSA bridge  
component. When the GMCH component receives an interrupt message, it forwards the interrupt  
through a PIRQ programmed into the CSA Interface Interrupt Control Register (CSAINTC). Use  
the following information to program this register:  
Address Offset - 48h  
Default Value - 04h  
Access - R/W  
Size - 8 bits  
Bit Field - [2:1]  
Description - PCI Interrupt type for CSA generated Interrupt - R/W  
00 - Reserved  
01 - INT#B  
10 - INT#C (default)  
11 - INT#D  
Interrupts are communicated with a special CSA bus cycle that causes the MCH to issue an  
interrupt to the interrupt controller in the ICH.  
4.6  
LAN Disable  
For LAN designs, it is often desirable to program the BIOS setup to selectively enable or disable  
LOM devices. This capability gives the end user more control over system resource management  
and avoids conflicts with add-in boards.  
Device presence or absence must be established early during BIOS execution to ensure that  
resource allocation (interrupts and memory) is performed correctly. This task is frequently  
accomplished using a BIOS CVDR (Configuration Values Driven on Reset) mechanism.  
The 82541xx and 82547GI/EI LAN disable function resides on the FLSH_SO pin. This pin should  
be driven by a port on the system Super IO device so that BIOS can control it dependably.  
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4.7  
CardBus Application (82541PI/GI/EI Only)  
The 82541PI/GI/EI has some features to facilitate its use in a CardBus application, following  
revision 7 of the PC Card specification.  
To use the 82541PI/GI/EI on CardBus, an external flash memory is required. Configure the Base  
Address Registers to 32-bit (required for CardBus) and enable CLKRUN in EEPROM. Setting  
these bits also enables the CardBus Information Space (CIS) pointer in the PCI Configuration  
Space. When enabled, the CIS pointer starts the first tuple of the CIS chain at byte address 20h in  
the Flash device. The PC Card specification requires that this tuple be a CISTPL_LINKTARGET  
tuple. The tuple chain can then continue within the memory.  
When operating as a CardBus card, the 82541PI/GI/EI supports full functionality with the  
exception of wake up.  
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EEPROM Interface  
5
5.1  
General Overview  
The PCI/PCI-X Family of Gigabit Ethernet Controllers uses an EEPROM device for storing  
product configuration information. The EEPROM is divided into four general regions:  
• Hardware accessed – loaded by the Ethernet controller after power-up, PCI Reset  
deassertion, D3->D0 transition, or software commanded EEPROM reset  
(CTRL_EXT.EE_RST).  
• ASF accessed – loaded by the Ethernet controller in ASF mode after power-up, ASF Soft  
Reset (ASF FRC_RST), or software commanded ASF EEPROM read (ASF FRC_EELD).  
• Software accessed – used by software only. The meaning of these registers as listed here is a  
convention for the software only and is ignored by the Ethernet controller.  
• External BMC (TCO) accessed – loaded by an external BMC (TCO) from the SMBus after  
power up.  
Note: The 82544GC/EI and 82541ER do not support ASF, SMBus, or an external BMC (TCO).  
Several words of the EEPROM are accessed automatically by the Ethernet controller after reset to  
provide pre-boot configuration data before it is accessed by host software. The remainder of the  
stored information is available to software for storing the MAC address, serial numbers, and  
additional configuration information.  
Intel has a software utility called EEUPDATE, which can be used to program EEPROM images in  
development or production line environments. To obtain a copy of this program, contact your Intel  
representative.  
Note: Since the 82546GB/EB is a dual port device, there are portions of the EEPROM and Flash that  
control one or both ports. Special considerations due to this feature are noted in this section.  
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5.2  
Component Identification Via Programming  
Interface  
Ethernet controller stepping is identified by the following register contents.  
Table 5-1. Component Identification  
Stepping  
82547EI-A0  
Vendor ID  
8086h  
Device ID  
1019h  
Description  
Copper  
82547EI-A1  
82547EI-B0  
82547EI-B0  
82547GI-B0  
8086h  
8086h  
8086h  
8086h  
1019h  
1019h  
101Ah  
1019h  
Copper  
Copper  
Mobile  
Copper  
Copper; Dual Port  
MAC Default  
82546EB-A1  
8086h  
1010h  
82546EB-A1  
82546EB-A1  
82546GB-B0  
82546GB-B0  
82546GB-B0  
82545EM-A  
82545EM-A  
8086h  
8086h  
8086h  
8086h  
8086h  
8086h  
8086h  
1012h  
101Dh  
1079h  
107Ah  
107Bh  
100Fh  
1011h  
Fiber; Dual Port  
Copper; Quad Port  
Copper; Dual Port  
Fiber; Dual Port  
SerDes; Dual Port  
Copper  
Fiber  
Copper  
82545GM-B  
8086h  
1026h  
MAC Default  
82545GM-B  
82545GM-B  
8086h  
8086h  
1027h  
1028h  
Fiber  
SerDes  
Copper  
82544EI-A4  
82544GC-A4  
82541EI-A0  
82541EI-A0  
8086h  
8086h  
8086h  
8086h  
1107h  
1112h  
1013h  
1013h  
MAC Default  
Copper  
MAC Default  
Cooper  
MAC Default  
Cooper  
MAC Default  
Cooper  
82541EI-B0  
82541EI-B0  
8086h  
8086h  
1013h  
1018h  
MAC Default  
Mobile  
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Table 5-1. Component Identification  
Stepping  
82541GI-B1  
Vendor ID  
8086h  
Device ID  
1076h  
Description  
Cooper  
82541GI-B1  
82541PI-C0  
82541ER-C0  
82540EP-A  
82540EP-A  
82540EM-A  
82540EM-A  
8086h  
8086h  
8086h  
8086h  
8086h  
8086h  
8086h  
1077h  
1076h  
1078h  
1017  
Mobile  
Cooper  
Cooper  
Desktop  
Mobile  
1016  
100E  
1015  
Desktop  
Mobile  
Note: These Ethernet controllers also provide identification data through the Test Access Port (TAP).  
5.3  
EEPROM Device and Interface  
The EEPROM access algorithm, programmed into the Ethernet controller, is compatible with most,  
but not all, commerically available 3.3 V dc Microwire* interfaces and serial EEPROM devices  
with a 1 MHz speed rating. Ethernet controllers are compatible with two sizes of 4-wire serial  
1
EEPROM devices . If ASF mode functionality is desired, a 4096-bit serial NM93C66 compatible  
EEPROM can be used. Otherwise, a 1024-bit serial NM93C46 compatible EEPROM can be used.  
Both EEPROMs are accessed in 16-bit words; the larger has 256 words while the smaller has 64  
words. Refer to the appropriate Ethernet controller’s design guide for recommended EEPROM  
manufacturers.  
An Ethernet controller automatically determines which EEPROM it is connected to and sets the  
EEPROM SIZE field of the EEPROM/FLASH Control and Data Register (EEC.EE_SIZE) field  
appropriately. Software can use this field to determine how to access the EEPROM using direct  
access. Note that different EEPROM sizes have different numbers of address bits and therefore  
must be accessed with a slightly different serial protocol. Software must be aware of this if it  
accesses the EEPROM using direct access.  
1. The 82544GC/EI only supports one size of EEPROM. Refer to the 82544GC Gigabit Ethernet Controller Datasheet and Hardware Design  
Guide (AP-427) for more information.  
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The EEPROM interface trace routing is not critical because the interface runs at a very slow speed.  
Note: For the 82544GC/EI, 82540EP/EM, 82541xx, and 82547GI/EI, the EEPROM access algorithm  
drives extra pulses on the shift clock at the beginnings and ends of read and write cycles. the extra  
pulses might violate the timing specifications of some EEPROM devices. In selecting a serial  
EEPROM, choose a device that specifies “don’t care” shift clock states between accesses.  
5.3.1  
Software Access  
The Ethernet controller provides two different methods for software access to the EEPROM.  
Software can either use the built-in controller to read the EEPROM, or access the EEPROM  
directly using the EEPROM’s 4-wire interface.  
Software can use the EEPROM Read register (EERD) to cause the Ethernet controller to read a  
word from the EEPROM that the software can then use. To do this, software writes the address to  
read the Read Address (EERD.ADDR) field and then simultaneously writes a 1b to the Start Read  
bit (EERD.START). The Ethernet controller then reads the word from the EEPROM, sets the Read  
Done bit (EERD.DONE), and puts the data in the Read Data field (EERD.DATA). Software can  
poll the EEPROM Read register until it sees the EERD.DONE bit set, then use the data from the  
EERD.DATA field. Any words read this way are not written to hardware’s internal registers.  
Software can also directly access the EEPROM’s 4-wire interface through the EEPROM/FLASH  
Control Register (EEC). It can use this for reads, writes, or other EEPROM operations.  
To directly access the EEPROM, software should follow these steps:  
1. Write a 1b to the EEPROM Request bit (EEC.EE_REQ).  
2. Read the EEPROM Grant bit (EEC.EE_GNT) until it becomes 1b. It remains 0b as long as the  
hardware is accessing the EEPROM.  
3. Write or read the EEPROM using the direct access to the 4-wire interface as defined in the  
EEPROM/FLASH Control & Data Register (EEC). The exact protocol used depends on the  
EEPROM placed on the board and can be found in the appropriate data sheet.  
4. Write a 0b to the EEPROM Request bit (EEC.EE_REQ).  
Software can cause the Ethernet controller to re-read the hardware accessed fields of the EEPROM  
(setting hardware’s internal registers appropriately) by writing a 1b to the EEPROM Reset bit of  
the Extended Device Control Register (CTRL_EXT.EE_RST). This action will also cause a reset.  
5.4  
Signature and CRC Fields  
The Ethernet controller uses the Signature and CRC fields to determine if an EEPROM is present  
by attempting to read the EEPROM. The Ethernet controller first reads the Initialization Control  
Word 1 at address 0Ah and then checks the received value for bits 15 and 14. If bit 15 is 0b and bit  
14 is 1b, the Ethernet controller considers the EEPROM to be present and valid. It then reads the  
additional EEPROM words and programs its internal registers based on the values read. Otherwise,  
it ignores the values it read from the Initialization Control Word 1 and does not read any other  
words.  
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1
In ASF Mode , the Ethernet controller's ASF function reads the ASF CRC word to determine if the  
EEPROM is valid. If the CRC is not valid, the ASF Configuration registers retain their default  
value. This CRC does not affect any of the remaining Ethernet controller's configuration, including  
the Management Control Register.  
5.5  
EEUPDATE Utility  
The EEUPDATE utility meets the two basic requirements for an in-circuit programming utility.  
First, the utility can be used to update EEPROM images as part of an end-of-line production tool.  
Secondly, it can be used as a standalone development tool. The tool uses the two basic data files  
outlined in the following section (static data file and IA address file). To obtain a copy of this  
program, contact your Intel representative.  
The EEUPDATE utility is flexible and can be used to update the entire EEPROM image or update  
only the IA address of the Ethernet controller.  
5.5.1  
Command Line Parameters  
The DOS command format is a follows:  
EEUPDATE Parameter_1 Parameter_2  
where:  
Parameter_1 = filename or /D  
Parameter_2 = filename or /A  
Parameter 1, above, is file1.eep, which contains the complete EEPROM image in a  
specific format that is used to update the complete EEPROM. All comments in the .eepfile must  
be preceded by a semicolon (;).  
Parameter 1can also be a switch /D. the switch /D implies: do not update the complete  
EEPROM image.  
Parameter 2, above, is file2.dat, which contains a list of IA addresses. the EEUPDATE  
utility picks up the first unused address from this file and uses it to update the EEPROM. An  
address is marked as used by following the address with a date stamp. When the utility uses a  
specific address, it updates that address as used in a log file called eelog.dat. This file should then  
be used as the .datfile for the next update.  
Note: Refer to the appropriate Ethernet controller’s EEPROM map and programming information for  
sample EEPROM images.  
1. The 82544GC/EI and 82541ER do not support ASF.  
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1
5.6  
EEPROM Address Map  
Table 5-2 lists the EEPROM address map for the Ethernet controllers. Each word listed is  
described in the sections that follow.  
Note: The “LAN A/B” column in Table 5-2 is only applicable to the 82546GB/EB.  
Table 5-2. Ethernet Controller Address Map  
Used  
By  
Bit  
15 - 8  
Bit  
7 - 0  
Image  
Value  
LAN  
A/B  
Word  
00h  
01h  
02h  
HW  
Ethernet Address Byte 2  
Ethernet Address Byte 4  
Ethernet Address Byte 6a  
Ethernet Address Byte 1  
Ethernet Address Byte 3  
Ethernet Address Byte 5  
IA(2,1)  
LAN  
A/B  
(both)  
HW  
HW  
IA(4,3)  
IA(6,5)  
03h  
04h  
Compatibility High  
Compatibility Low  
0000h  
FFFFh  
both  
both  
SerDes Configuration  
SW  
SW  
Note: Not applicable to the 82540EP/EM, 82541xx, and  
82547GI/EI  
EEPROM Image Version  
05h  
0000h  
N/A  
Note: Applicable to the 82541xx and 82547GI/EI only  
Compatibility High  
Compatibility Low  
05h  
06h  
07h  
0000h  
0000h  
0000h  
(Words 06h and 07h reserved  
for the 82541xx and 82547GI/  
EI)  
(Words 06h and 07h reserved  
for the 82541xx and 82547GI/  
EI)  
both  
08h  
09h  
PBA, byte 1  
PBA, byte 3  
PBA, byte 2  
PBA, byte 4  
4408h  
640Ah for  
the  
0Ah  
HW  
Init Control 1  
both  
82541xx  
and  
82547GI/EI  
see Table  
5-1 for  
0Bh  
0Ch  
HW  
HW  
Subsystem ID (Vendor)  
Subsystem Vendor ID  
specific  
image  
values  
both  
both  
8086h  
1. Refer to Table 5-3 for the 82544GC/EI and 82541ER EEPROM address map.  
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Table 5-2. Ethernet Controller Address Map  
Used  
By  
Bit  
15 - 8  
Bit  
7 - 0  
Image  
Value  
LAN  
A/B  
Word  
see Table  
5-1 for  
0Dh  
0Eh  
HW  
Device ID  
Vendor ID  
specific  
image  
values  
LAN A  
both  
HW  
8086h  
3040h for  
the  
82545GM/  
EM and  
82540EP/  
EM  
0Fh  
HW  
Init Control 2  
both  
B080h for  
the  
82541xx  
and  
82547GI/EI  
10h  
11h  
PHY Registers  
00BAh  
0000h  
SW  
HW  
N/A  
82541xx and 82547GI/EI only  
Software Defined Pins Control (82546GB/EB only)  
10h  
11h  
XXXXh  
LAN B  
Note: Words 10h, 11h, and 13h through 1Fh are reserved for the  
82545GM/EM and 82540EP/EM  
see Table  
5-1 for  
specific  
image  
Device ID  
HW  
LAN B  
82546GB/EB only  
values  
EEPROM Size  
12h  
12h  
HW  
HW  
SW  
N/A  
both  
N/A  
82541xx and 82547GI/EI only  
Common Power  
13h  
1Eh  
PHY Registers  
00BAh  
0000h  
82541xx and 82547GI/EI only  
13h  
14h  
HW  
HW  
Management Control  
LAN B  
LAN B  
Init Control 3  
SMBus Addressb  
XXXXh  
15h  
16h  
IPv4 Address Byte 2  
IPv4 Address Byte 4  
IPv4 Address Byte 1  
IPv4 Address Byte 3  
IP(2,1)  
IP(4,3)  
HW  
LAN B  
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Table 5-2. Ethernet Controller Address Map  
Used  
By  
Bit  
15 - 8  
Bit  
7 - 0  
Image  
Value  
LAN  
A/B  
Word  
17h  
18h  
19h  
1Ah  
1Bh  
1Ch  
1Dh  
1Eh  
IPv6 Address Byte 2  
IPv6 Address Byte 4  
IPv6 Address Byte 6  
IPv6 Address Byte 8  
IPv6 Address Byte 10  
IPv6 Address Byte 12  
IPv6 Address Byte 14  
IPv6 Address Byte 16  
IPv6 Address Byte 1  
IPv6 Address Byte 3  
IPv6 Address Byte 5  
IPv6 Address Byte 7  
IPv6 Address Byte 9  
IPv6 Address Byte 11  
IPv6 Address Byte 13  
IPv6 Address Byte 15  
IP(2,1)  
IP(4,3)  
IP(6,5)  
IP(8,7)  
HW  
LAN B  
IP(10,9)  
IP(12,11)  
IP(14,13)  
IP(16,15)  
CSA Port Config 1 (82547GI/EI only)  
1Fh  
0000h  
N/A  
Note: This word is reserved for all remaining Ethernet controllers  
XXXXh  
000Ch for  
the  
82541xx  
and  
20h  
HW  
Software Defined Pins Control  
LAN A  
82547GI/EI  
21h  
21h  
HW  
HW  
CSA Port Config 2 (82547GI/EI only)  
0002h  
7863h  
N/A  
7061h for  
the  
Circuit Control  
both  
82540EP/  
EM  
280Ch  
280Bh for  
the  
82541xx  
and  
22h  
23h  
HW  
HW  
D0 Power  
D3 Power  
both  
82547GI/EI  
XXC8h  
XXXXh for  
the  
82541xx  
and  
Management Control  
LAN A  
82547GI/EI  
XXXXh  
XXC8h for  
the  
82545GM/  
EM and  
82540EP/  
EM  
24h  
HW  
Init Control 3  
SMBus Addressb  
LAN A  
001Ch for  
the  
82541xx  
and  
82547GI/EI  
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Table 5-2. Ethernet Controller Address Map  
Used  
By  
Bit  
15 - 8  
Bit  
7 - 0  
Image  
Value  
LAN  
A/B  
Word  
25h  
26h  
IPv4 Address Byte 2  
IPv4 Address Byte 4  
IPv4 Address Byte 1  
IPv4 Address Byte 3  
IP(2,1)  
HW  
LAN A  
IP(4,3)  
27h  
28h  
29h  
2Ah  
2Bh  
2Ch  
2Dh  
2Eh  
IPv6 Address Byte 2  
IPv6 Address Byte 4  
IPv6 Address Byte 6  
IPv6 Address Byte 8  
IPv6 Address Byte 10  
IPv6 Address Byte 12  
IPv6 Address Byte 14  
IPv6 Address Byte 16  
IPv6 Address Byte 1  
IPv6 Address Byte 3  
IPv6 Address Byte 5  
IPv6 Address Byte 7  
IPv6 Address Byte 9  
IPv6 Address Byte 11  
IPv6 Address Byte 13  
IPv6 Address Byte 15  
IP(2,1)  
IP(4,3)  
IP(6,5)  
IP(8,7)  
HW  
HW  
LAN A  
both  
IP(10,9)  
IP(12,11)  
IP(14,13)  
IP(16,15)  
2Fh  
LEDCTL Default  
Intel Boot Agent Configuration  
0602h  
30h  
31h  
32h  
33h  
34h  
...  
Firm-  
ware  
…
Note: Words 34h and 35h are not applicable to the 82545GM/EM  
and 82540EP/EM  
3Eh  
3Fh  
Software Checksum, words 00h through 3Fh  
Controlled by the ASF Agent  
40h  
...  
ASF  
F7h  
F8h  
...  
Free for Software  
FFh  
a. The lower bit of the last byte is complemented for LAN B.  
b. The SMBus Address is a 7-bit value that is found in bits 7 through 1 of this byte. Bit 0 should be 0b.  
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Table 5-3. 82544GC/EI and 82541ER EEPROM Address Map  
Default  
Image Value  
(hex)  
Word  
Address  
Description  
(Hi Byte)  
Description  
(Low Byte)  
HW Access  
00h  
Yes  
IA Byte 2  
IA Byte 1  
IA(2,1)  
01h  
02h  
03h  
04h  
Yes  
Yes  
No  
IA Byte 4  
IA Byte 3  
IA(4,3)  
IA(6,5)  
0000h  
0000h  
IA Byte 6  
IA Byte 5  
Compatibility high  
Compatibility low  
No  
Reserved  
EEPROM Image Version  
05h  
No  
0000h  
0000h  
Note: Word 05h is reserved for the 82544GC/EI  
06h  
07h  
No  
No  
Reserved  
08h  
PBA, byte 1  
PBA, byte 2  
09h  
0Ah  
No  
PBA, byte 3  
PBA, byte 4  
Yes  
Init Control 1, high byte  
Init Control 1, low byte  
See Text  
1005h  
Subsystem_ID,  
high byte  
Subsystem_ID,  
low byte  
0Bh  
0Ch  
Yes  
Yes  
Subsystem_Vendor,  
high byte  
Subsystem_Vendor,  
low byte  
8086h  
0Dh  
Yes  
Yes  
Yes  
No  
Device ID, high  
Device ID, low  
1008h  
0Eh  
Vendor ID, high  
Vendor ID, low  
8086h  
0Fh  
Init Control 2, high byte  
OEM Reserved  
Init Control 2, low byte  
OEM Reserved  
See Text  
0000h  
10h - 1Fh  
Software Defined Pins  
Control, high byte  
Software Defined Pins  
Control, low byte  
20h  
Yes  
See Text  
21h  
Yes  
Yes  
No  
Circuit Control, high  
D0 Power  
Circuit Control, low  
D3 Power  
0021h  
22h  
See Text  
0000h  
23h - 2Eh  
Reserved  
Reserved  
LEDCTRL Default  
2Fh  
Yes  
0602h  
Note: Word 2Fh is reserved for the 82544GC/EI  
Intel Boot Agent  
30h - 33h  
Firmware  
0000h  
0000h  
Note: Words 30 - 33h are reserved for the 82541ER  
34h - 3Eh  
3Fh  
Fixed  
No  
Reserved  
Reserved  
Checksum of  
words 00h - 3Eh  
Checksum, high byte  
Checksum, low byte  
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5.6.1  
Ethernet Address (Words 00h-02h)  
The Ethernet Individual Address (IA) is a six-byte field that must be unique for each Ethernet port  
(and unique for each copy of the EEPROM image). The first three bytes are vendor specific. The  
value from this field is loaded into the Receive Address Register 0 (RAL0/RAH0). For a MAC  
address of 12-34-56-78-90-AB, words 2:0 load as follows (note that these words are byte-  
swapped):  
Word 0 = 3412  
Word 1 = 7856  
Word 2 - AB90  
Note: Since the 82546GB/EB is a dual-port device, the Ethernet Address in these words are assigned to  
LAN A. The Ethernet Address for LAN B is the Ethernet Address for LAN A with its least  
significant bit inverted.  
5.6.2  
Software Compatibility Word (Word 03h)  
This is the third word read by the Ethernet controller and contains additional initialization values  
that:  
• Sets defaults for some internal registers  
• Enables/disables specific features  
Note: For the 82544GC/EI, typical values are 0000h for a fiber-based design and 0400h for a copper-  
based design.  
Table 5-4. Software Compatibility Word (Word 03h)  
Bit  
Name  
Reserved  
Description  
15:12  
Reserved for future use.  
LAN on Motherboard (LOM#). Set this bit to 1b (default) to enable LOM#;  
set to 0b to disable LOM#.  
11  
10  
LOM  
SRV  
Server card. Set this bit to 1b (default) to enable server card; set to 0b to  
disable server card.  
0b is the default setting for the 82541xx and 82547GI/EI.  
Client card. Set this bit to 0b (default) to disable client card; set to 1b to  
enable client card.  
9
CLI  
1b is the default setting for the 82541xx and 82547GI/EI.  
OEM card. Set this bit to 1b (default) to enable OEM card; set to 0b to  
disable OEM card.  
8
OEM  
7:6  
Reserved  
Reserved for future use. Set these bits to 0b.  
Reserved for future use.  
5
4
Reserved  
SMBa  
Set this bit to 1b.  
Set this bit to 0b for the 82540EP/EM, 82541xx and 82547GI/EI.  
SMBus. Set this bit to 1b (default) to enable SMBus; set to 0b to disable  
SMBus.  
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Table 5-4. Software Compatibility Word (Word 03h)  
3
Reserved  
Reserved for future use. Set this bit to 0b.  
PCI bridge. Set this bit to 0b (default) to disable PCI bridge; set to 1b to  
enable PCI bridge.  
2
BOB  
1b is the default setting for the 82540EP/EM.  
1:0  
Reserved  
Reserved for future use. Set these bits to 0b.  
a.  
Not applicable to the 82544GC/EI or 82541ER.  
5.6.3  
5.6.4  
SerDes Configuration (Word 04h)  
If this word has a value of other than FFFFh, software programs its value into the Extended PHY  
Specific Control Register 2, located at address 26d in the PHY register space (see Table 13-47).  
Note: SerDes Configuration (Word 04h) is a reserved area for the 82544GC/EI, 82540EP/EM, 82541xx,  
and 82547GI/EI.  
EEPROM Image Version (Word 05h)  
Word 05h determines the EEPROM image version for the 82541xx and the 82547GI/EI.  
Bits  
Name  
EEPROM major version.  
Value  
15:12  
11:8  
7:0  
0000h  
EEPROM minor version.  
EEPROM fix.  
0000h  
00000000h  
5.6.5  
5.6.6  
Compatibility Fields (Word 05h - 07h)  
These areas are reserved for compatibility information and are used by software drivers.  
PBA Number (Word 08h, 09h)  
A nine-digit Printed Board Assembly (PBA) number, used for Intel manufactured adapter cards,  
are stored in a four-byte field. Other hardware manufacturers can use these fields as they wish.  
Software device drivers should not rely on this field to identify the product or its capabilities.  
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5.6.7  
Initialization Control Word 1 (Word 0Ah)  
The first word read by the Ethernet controller contains initialization values that:  
• Sets defaults for some internal registers  
• Enables/disables specific features  
• Determines which PCI configuration space values are loaded from the EEPROM  
Table 5-5. Initialization Control Word 1 (Word 0Ah)  
Bit  
Name  
Description  
The Signature field represents a signature of 01b (default), indicating to the  
Ethernet controller that there is a valid EEPROM present.  
15:14  
Signature  
If the Signature field is not 01b, the other bits in this word are ignored, no  
further EEPROM read is performed, and default values are used for the  
configuration space IDs.  
When set to 0b (default), enables 64-bit memory mapping.  
When set to 1b, disables 64-bit memory mapping  
Note: Set to 1b for the 82540EP/EM.  
13  
12  
64/32 BAR  
IPS0  
When set to 0b (default), does not invert the Power State Output bit 0  
(CTRL_EXT[14]).  
When set to 1b, inverts the Power State Output invert bit 0  
(CTRL_EXT[14]).  
Note: Reserved bit for the 82541xx and 82547GI/EI (set to 0b).  
Force Speed bit in the Device Control register (CTRL[11]).  
When set to 0b (default), does not force speed.  
When set to 1b, forces speed (default for the 82540EP/EM).  
11  
10  
FRCSPD  
For 10/100/1000 Mb/s systems using TBI mode (82544GC/EI)/internal  
SerDes (82546GB/EB and 82545GM/EM)a, set this bit to 0b.  
Note: Reserved bit for the 82541xx and 82547GI/EI (set to 0b).  
Full Duplex (mapped to CTRL[0] and TXCW[5]).  
When set to 1b (default), enables full duplex (TBI mode/internal SerDes  
only).  
FD  
When set to 0b, disables full duplex (TBI mode only/internal SerDes).  
Note: Reserved bit for the 82541PI/GI/EI and 82547GI/EI (set to 1b).  
Note: Reserved bit for the 82541ER (set to 0b).  
Link Reset (mapped to CTRL[3]).  
When set to 0b, enables Auto-Negotiation at power up or when asserting  
RST# without driver intervention.  
9
8
LRST  
IPS1  
When set to 1b, disables Auto-Negotiation at power up or when asserting  
RST# without driver intervention.  
Note: Reserved bit for the 82541xx and 82547GI/EI (set to 0b).  
When set to 0b (default), does not invert the Power State Output bit 1  
(CTRL_EXT[16]).  
When set to 1b, inverts the Power State Output invert bit 1  
(CTRL_EXT[16]).  
Note: Reserved bit for the 82541xx and 82547GI/EI (set to 0b).  
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Table 5-5. Initialization Control Word 1 (Word 0Ah)  
82541xx and 82547GI/EI Only  
This bit is used to define the usage of the internal 1.2 V dc and 1.8 V dc  
regulators to supply power.  
Internal VREG Power  
Down Control  
7
0b = Yes (default).  
1b = No (external regulators used).  
Note: Reserved bit for all other Ethernet controllers.  
Bit  
Name  
Description  
6:5  
4
Reserved  
Reserved  
Reserved for future use. Set these bits to 0b.  
Reserved for copper PHY. Set this bit to 0b.  
When set to 1b (default), enables full support for power management.  
When set to 0b, the Power Management Registers set is read only. The  
Ethernet controller does not execute a hardware transition to D3.  
3
Power Management  
Note: Reserved bit for the 82541PI/GI/EI and 82547GI/EI (set to 1b).  
Note: Reserved bit for the 82541ER (set to 0b).  
When set to 0b (default), indicates that the PCICLK is not required for  
PME# output.  
2
1
PME Clock  
When set to 1b, indicates that the PCICLK is required for PME# output.  
Note: Reserved bit for the 82541xx and 82547GI/EI (set to 0b).  
When set to 1b (default), indicates that the Ethernet controller is to load its  
PCI Subsystem ID and Subsystem Vendor ID from the EEPROM (words  
0Bh, 0Ch).  
Load Subsystem IDs  
When set to 0b, indicates that the Ethernet controller is to load the default  
PCI Subsystem ID and Subsystem Vendor ID.  
When set to 0b (default), indicates that the Ethernet controller is to load the  
default values for PCI Vendor and Device IDs.  
Load Vendor/Device  
IDs  
0
When set to 1b (default for the 82541xx and 82547GI/EI only), indicates  
that the Ethernet controller is to load its PCI Vendor and Device IDs from  
the EEPROM (words 0Dh, 0Eh).  
a.  
Not applicable to the 82541xx, 82547GI/EI or 82540EP/EM.  
5.6.8  
5.6.9  
Subsystem ID (Word 0Bh)  
If the signature bits (15:14) and bit 1 (Load Subsystem IDs) of word 0Ah are valid, this word is  
read in to initialize the Subsystem ID.  
Subsystem Vendor ID (Word 0Ch)  
If the signature bits (15:14) and bit 1 (Load Subsystem IDs) of word 0Ah are valid, this word is  
read in to initialize the Subsystem Vendor ID.  
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5.6.10  
Device ID (Word 0Dh, 11h1)  
If the signature bits (15:14) and bit 1 (Load Subsystem IDs) of word 0Ah are valid, this word is  
read in to initialize the Subsystem ID.  
For the 82546GB, the Device ID must be forced to 107Bh for SerDes-SerDes interface operation.  
For the 82545GM, the Device ID should be 1028h. This ensures proper functionality with Intel  
drivers and boot agent.  
Note: Since the 82546GB/EB is a dual-port device, the Device ID in 0Dh corresponds to LAN A and the  
Device ID in 11h corresponds to LAN B.  
5.6.11  
Vendor ID (Word 0Eh)  
If the signature bits (15:14) and bit 1 (Load Subsystem IDs) of word 0Ah are valid, this word is  
read in to initialize the Subsystem ID.  
5.6.12  
Initialization Control Word 2 (Word 0Fh)  
This is the second word read by the Ethernet controller and contains additional initialization values  
that:  
• Sets defaults for some internal registers  
• Enables/disables specific features  
Table 5-6. Initialization Control Word 2 (Word 0Fh)  
Bit  
Name  
Description  
Initial value of the Assert PME On APM Wakeup bit in the Wakeup Control  
Register (WUC.APMPME).  
15  
APM PME# Enable  
When set to 0b (default), deasserts PME# on wakeup.  
Set this bit to 1b for Intel LAN controller cards.  
When set to 0b (default), indicates the initial value of the Auto-Speed  
Detection Enable (ASDE) bit of the Device Control Register (CTRL).  
14  
ASDE  
When set to 1b, enables 10/100/1000 Mb/s systems.  
Pause Capability - Mapped to TXCW[8:7].  
When set to 1b (default), enables desired PAUSE capability for an  
advertised configuration base page.  
13:12  
PAUSE Capability  
ANE  
When set to 0b, disables desired PAUSE capability for an advertised  
configuration base page.  
Auto-Negotiation Enable. Mapped to TXCW[31].  
Reserved bit for the  
82541xx and  
82547GI/EI (set to  
0b).  
Set this bit to 1b to automatically enable Auto-Negotiation.  
Set this bit to 0b (default) to automatically disable Auto-Negotiation.  
Note: Fiber implementations do not support this function.  
11  
Indicates FLASH size. 00b = 64 KB (default); 01b = 128 KB; 10b = 256 KB;  
11b = 512 KB.  
10:9  
FLASH Size Indication  
These bits also impact the requested memory space for the FLASH and  
Expansion ROM BARs in PCI configuration space.  
1. Word 11h only applicable to the 82546GB/EB.  
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Table 5-6. Initialization Control Word 2 (Word 0Fh)  
Bit  
Name  
Description  
82541PI/GI Only.  
0b = MAC runs at full speed.  
8
7
MAC Clock Speed  
1b = MAC runs at 1/4 speed on any drop from 1000 Mb/s.  
Note: Reserved bit for all other Ethernet controllers (set to 0b). Formally  
FLASH Disable, now located in Initialization Control Word 3, bit 3.  
When set to 0b (default), enables Message Signalled Interrupts (MSI) in  
standard PCI mode.  
MSI Disable  
When set to 1b, disables Message Signalled Interrupts (MSI) in standard  
PCI mode.  
Note: Reserved bit for the 82541xx and 82547GI/EI (set to 1b).  
When set to 1b (default), maps the 133 MHz Capable bit of the PCI-X  
Status Register (PCIXS).  
When set to 0b, does not map the 133 MHz Capable bit of the PCI-X Status  
Register (PCIXS).  
6
5
133 MHz Capable  
Note: Reserved bit for the 82541xx, 82547GI/EI, and 82540EP/EM (set to  
0b).  
Indicates how the Designed Maximum Cumulative Read size bits in the  
PCI-X Status register are mapped.  
When set to 1b (default), the DMCR value reflects the hard-coded design  
capability as indicated by the Max_Read bit (bit 4).  
DMCR_Map  
When set to 0b, the DMCR is mapped directly to the Maximum Memory  
Read Byte Count indicated in the PCI-X Command register.  
Note: Reserved bit for the 82541xx, 82547GI/EI, and 82540EP/EM (set to  
0b).  
Indicates the maximum read value as advertised in the Designed Maximum  
Memory Read Byte Count field in the PCI-X Status Register.  
When set to 0b (default), or if there is no EEPROM, the advertised  
maximum read is 2 KB.  
4
Max_Read  
When set to 1b, the advertised maximum read is 4 KB. Note that it is not  
recommended to set Max_Read to 1b because transmit FIFO overruns are  
possible under specific operating conditions.  
Note: Reserved bit for the 82541xx, 82547GI/EI, and 82540EP/EM (set to  
0b).  
When set to 1b (default), loads the 64-bit Device field of the PCI-X Status  
Register.  
When set to 0b, does not load the 64-bit Device field of the PCI-X Status  
Register.  
3
2
64-bit  
Note: Reserved bit for the 82541xx, 82547GI/EI, and 82540EP/EM (set to  
0b).  
Reserved for future use (set to 0b). Formerly APM Enable, now located in  
Initialization Control Word 3, bit 2.  
Reserved  
Note: Set to 1b for the 82541xx and 82547GI/EI.  
When set to 0b (default), certain critical registers are decoded for non-split  
access.  
1
0
Force CSR Read Split When set to 1b, forces all Ethernet controller control/status register-reads  
to be split when operating in a PCI-X environment.  
Note: Reserved bit for the 82541xx and 82547GI/EI (set to 0b).  
Reserved  
Reserved for future use (set to 0b).  
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5.6.13  
PHY Register Address Data (Words 10h, 11h, and 13h - 1Eh)  
These settings are specific to individual platform configurations for the 82541xx and 82547GI/EI  
and should not be altered from the reference design unless instructed to do so. Future Intel Ethernet  
controllers might use this space differently.  
5.6.14  
5.6.15  
OEM Reserved Words (Words 10h, 11h, 13h - 1Fh)  
Words 10h, 11h, and 13h through 1Fh of the EEPROM are reserved areas for general OEM use for  
all Ethernet controllers except the 82546GB/EB.  
EEPROM Size (Word 12h)  
This word is only applicable to 82541xx and 82547GI/EI Ethernet controllers that use SPI  
EEPROMs. Unused bits are reserved and should be programmed to 0b. Bits 15:13 and 8:0 are  
reserved (see Table 5-7).  
Table 5-7. SPI EEPROM Sizes  
Bits 12:10  
000  
Bit 9  
EEPROM Size (Bits)  
EEPROM Size (Bytes)  
128 Bytes  
0
1
1
1
1
1
1
1
1 Kb  
001  
010  
011  
100  
101  
110  
111  
4 Kb  
512 Bytes  
1 KB  
8 Kb  
16 Kb  
32 Kb  
64 Kb  
2 KB  
4 KB  
8 KB  
128 Kb  
16 KB  
Reserved  
Reserved  
5.6.16  
5.6.17  
Common Power (Word 12h)  
For all Ethernet controllers except the 82541xx and 82547GI/EI, if the signature bits are valid and  
Power Management is not disabled, the value in this field is used in the PCI Power Management  
Data Register when the Data_Select field of the Power Management Control/Status Register  
(PMCSR) is set to 8. This setting indicates the power usage and heat dissipation of the common  
logic that is shared by both functions in tenths of a watt.  
Software Defined Pins Control (Word 10h1, 20h)  
This field contains initial settings for the Software Defined Pins (SPD). The default value for the  
upper byte (bits 15:8) is DFh; the default value for the lower byte (bits 7:0) is DEh.  
1. Applicable to the 82546GB/EB only.  
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Table 5-8. Software Defined Pins Control (Word 10h, 20h)  
Bit  
Name  
Description  
SDP7(3) Pin - Initial Direction.  
Set this bit to 0b (default) to configure the initial hardware value of  
the SDP7(3)_IODIR bit in the Extended Device Control Register  
(CTRL_EXT) following power up.  
SDPDIR[7]  
15  
SDPDIR[3] for the 82541xx  
and 82547GI/EI  
Set this bit to 1b if not connected on a board or if used as an  
output.  
SDP6(2) Pin - Initial Direction.  
Set this bit to 0b (default) to configure the initial hardware value of  
the SDP6(2)_IODIR bit in the Extended Device Control Register  
(CTRL_EXT) following power up.  
SDPDIR[6]  
14  
SDPDIR[2] for the 82541xx  
and 82547GI/EI  
Set this bit to 1b if not connected on a board or if used as an  
output.  
13:10  
9
Reserved  
Set these bits to 0b.  
SDP1 Pin - Initial Direction.  
Set this bit to 0b (default) to configure the initial hardware value of  
the SDP1_IODIR bit in the Extended Device Control Register  
(CTRL_EXT) following power up.  
SDPDIR[1]  
Set this bit to 1b if not connected on a board or if used as an  
output.  
SDP0 Pin - Initial Direction.  
Set this bit to 0b (default) to configure the initial hardware value of  
the SDP0_IODIR bit in the Extended Device Control Register  
(CTRL_EXT) following power up.  
8
7
SDPDIR[0]  
SDPVAL[7]  
Set this bit to 1b if not connected on a board or if used as an  
output.  
SDP7(3) Pin - Initial Output Value.  
Set this bit to 0b (default) to configure the initial power-on value  
output on SDP7(3) (when configured as an output) by configuring  
the initial hardware value of the SDP7(3)_DATA bit in the Extended  
Device Control Register (CTRL_EXT) after power up.  
SDPVAL[3] for the 82541xx  
and 82547GI/EI  
Set this bit to 1b if used as an output.  
SDP6(2) Pin - Initial Output Value.  
Set this bit to 0b (default) to configure the initial power-on value  
output on SDP6(2) (when configured as an output) by configuring  
the initial hardware value of the SDP6(2)_DATA bit in the Extended  
Device Control Register (CTRL_EXT) after power up.  
SDPVAL[6]  
6
SDPVAL[2] for the 82541xx  
and 82547GI/EI  
Set this bit to 1b if used as an output.  
Set these bits to 0b.  
5:4  
Reserved  
Set this bit to 1b (default) to configure the initial hardware default  
value of this bit in the Device Control Register (CTRL) following  
power up.  
3
EN_PHY_PWR_MGMT  
Set this bit to 0b to not configure the initial hardware default value  
of this bit in the Device Control Register (CTRL) following power  
up.  
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Table 5-8. Software Defined Pins Control (Word 10h, 20h)  
Bit  
Name  
Description  
Set this bit to 1b (default) to configure the initial hardware default  
value of the ADVD3WUC bit in the Device Control Register (CTRL)  
following power up.  
2
1
D3COLD_WAKEUP_ADV_EN  
Set this bit to 0b to not configure the initial hardware default value  
of the ADVD3WUC bit in the Device Control Register (CTRL)  
following power up.  
SDP1 Pin - Initial Output Value.  
Set this bit to 0b (default) to configure the initial power-on value  
output on SDP1 (when configured as an output) by configuring the  
initial hardware value of the SDP1_DATA bit in the Extended  
Device Control Register (CTRL_EXT) after power up.  
SDPVAL[1]  
SDPVAL[0]  
Set this bit to 1b if used as an output.  
SDP0 Pin - Initial Output Value.  
Set this bit to 0b (default) to configure the initial power-on value  
output on SDP0 (when configured as an output) by configuring the  
initial hardware value of the SDP0_DATA bit in the Extended  
Device Control Register (CTRL_EXT) after power up.  
0
Set this bit to 1b if used as an output.  
Note: Since the 82546GB/EB is a dual-port device, the SDP control in 10h corresponds to LAN B, and  
the SDP control in 20h corresponds to LAN A.  
5.6.18  
CSA Port Configuration 2 (Word 21h)  
For the 82547GI/EI only, this word controls the CSA port configuration and must be programmed  
to 93A7h for regular operation (see Table 5-9).  
Table 5-9. CSA Port Configuration 2 (Word 21h)  
Bit  
Description  
Default  
15:13  
12  
Reserved.  
Reserved.  
Reserved.  
Set to 100b.  
Set to 1b.  
11:2  
Set to 0011101001b.  
1b = Indicates Docked (default).  
0b = Indicates Undocked.  
1
0
Dock/Undock Polarity.  
Reserved.  
Set to 1b.  
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5.6.19  
Circuit Control (Word 21h)  
This word is loaded into the Circuit Control Register (CIRC) for setting PCI-X driver strength. See  
Table 5-2 and Table 5-3 for suggested values.  
Note: PCI-X is not applicable to the 82540EP/EM, 82541xx, and 82547GI/EI.  
5.6.20  
D0 Power (Word 22h high byte)  
If the signature bits are valid and Power Management is not disabled, the value in this field is used  
in the PCI Power Management Data Register when the Data_Select field of the Power  
Management Control/Status Register (PMCSR) is set to 0 or 4. This indicates the power usage and  
heat dissipation of the networking function (including the Ethernet controller and any other devices  
managed by the Ethernet controller) in tenths of a watt. For example:  
If word22h = 290E, POWER CONSUMPTION (in 1/10W, hex), then:  
bits 15:8 = 29h Power in D0a, 29h = 4.1W  
bits 7:0 = 0Eh Power in D3h, 0Eh = 1.4W  
5.6.21  
D3 Power (Word 22h low byte)  
If the signature bits are valid and Power Management is not disabled, the value in this field is used  
in the PCI Power Management Data Register when the Data_Select field of the Power  
Management Control/Status Register (PMCSR) is set to 3 or 7. This indicates the power usage and  
heat dissipation of the networking function (including the Ethernet controller and any other devices  
managed by the Ethernet controller) in tenths of a watt as described in Section 5.6.20.  
5.6.22  
5.6.23  
Reserved Words (23h - 2Eh)  
Words 23h through 2Eh of the EEPROM are reserved areas for the 82541ER.  
Reserved Words (23h - 2Fh)  
Words 23h through 2Fh of the EEPROM are reserved areas for the 82544GC/EI.  
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5.6.24  
Management Control (Word 13h1, 23h2)  
The following table lists the initial settings for the Management Control Register as well as valid  
bits for the IPv4 Address and the IPv6 Address.  
Table 5-10. Initial Management Control Register Settings  
Bit  
Name  
Description  
This bit controls the initial value of the MANC.RSP_EN bit.  
Enable ARP Response  
Filtering  
0b: ARP response packets are delivered to host memory.  
15  
1b: ARP response packets are delivered to the Ethernet controller  
for automatic ARP reply or forwarded to the BMC.  
14  
Reserved  
Reserved. Set this bit to 0b.  
This bit controls the initial value of the MANC.ARP_EN bit.  
0b: ARP request packets are delivered to host memory.  
13  
Enable ARP Request Filtering  
Reserved  
1b: ARP request packets are delivered to the Ethernet controller for  
automatic ARP reply or forwarded to the BMC.  
12:10  
Set these bits to 0b.  
This bit is controlled by the ASF agent. Manually set this bit for  
TCO mode.  
Set this bit to 0b (default) to control the initial value of the  
9
8
Enable RMCP 0298h Filtering MANC.0298_EN bit, which enables classifying UDP packets of port  
0298h as Management Packets for delivery to the SMBus or ASF  
controller.  
Set this bit to 0b if the SMBus is disabled.  
This bit is controlled by the ASF agent. Manually set this bit for  
TCO mode.  
Set this bit to 1b (default) to control the initial value of the  
Enable RMCP 026F Filtering  
MANC.0298_EN bit, which enables classifying UDP packets of port  
026Fh as Management Packets for delivery to the SMBus or ASF  
controller.  
Set this bit to 0b if the SMBus is disabled.  
IPv6 Address in the IP Address EEPROM register is valid. This is  
written to bit 16 of the IP Address Valid (IPAV[16]) register.  
7
6
IPv6 Address Valid  
IPv4 Address Valid  
IPv4 Address in the IP Address EEPROM register is valid. This is  
written to bit 0b of the IP Address Valid (IPAV[0]) register.  
82541PI/GI/EI and 82547GI/EI Only.  
This bit enables the flexible filter loaded from the EEPROM.  
0b = Disable flex filter.  
5
Flex Filter Enable  
1b = Enable flex filter.  
Note: Reserved bit for all other Ethernet controllers (set to 0b).  
4:3  
Reserved  
Set these bits to 0b.  
1. Applicable to the 82546GB/EB only.  
2. Not applicable to the 82544GC/EI or 82541ER.  
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Table 5-10. Initial Management Control Register Settings  
Bit  
Name  
Description  
This bit is controlled by the ASF agent. Manually set this bit for  
TCO mode.  
Reset the Ethernet controller on a ForceTCO SMBus Command  
with the “Force” bit set to 1b (default) in TCO mode, or on various  
conditions in ASF mode.  
2
Reset on Force TCO  
Set this bit to 0b if the SMBus is disabled.  
This bit is controlled by the ASF agent.  
Set this bit to 1b to enable ASF mode.  
1
0
ASF Mode  
Set this bit to 0b (default) for TCO mode and Intel’s ASF Agent  
implementation.  
This bit is controlled by the ASF agent. Manually set this bit for  
TCO mode.  
SMBus Enable  
Set this bit to 1b (default) to enable SMBus functionality.  
Set this bit to 0b to enable ASF mode if its being routed by LAN A  
and if LAN A is the active interface for ASF to the BIOS.  
Note: Since the 82546GB/EB is a dual-port device, the Management Control in 13h corresponds to LAN  
B, and the Management Control in 23h corresponds to LAN A.  
5.6.25  
SMBus Slave Address (Word 14h1 low byte, 24h low byte)  
The following table lists the SMBus slave address for TCO mode.  
Table 5-11. SMBus Slave Address  
Bit  
Name  
SMBus Slave Address  
Reserved  
Description  
These bits are controlled by the ASF agent. Manually set these bits for  
TCO mode.  
7:1  
Contains the SMBus slave address for TCO mode. This address must  
be 1100b 100b for ASF mode.  
0
Set this bit to 0b.  
Note: This byte must be C8h for ASF mode. For example, to program an address of 0011_001b, the byte  
should be set to 0011_0010b. When this address is used on the SMBus, the address byte is  
0011_0010b for writes and 0011_0011b for reads.  
Note: Since the 82546GB/EB is a dual-port device, the SMBus Slave Address in 14h corresponds to  
LAN B, and the SMBus Slave Address in 24h corresponds to LAN A.  
1. Applicable to the 82546GB/EB only.  
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5.6.26  
Initialization Control 3 (Word 14h1 high byte, 24h high byte)  
This word controls the general initialization values.  
Table 5-12. Initialization Control 3  
Bit  
7:5  
Name  
Description  
Reserved. Set these bits to 0b.  
Reserved  
Controls the value advertised in the Interrupt Pin field of the PCI  
Configuration header for this device/function.  
A value of 0b (default), reflected in the Interrupt Pin field, indicates that  
the 82546GB/EB uses INTA#; a value of 1b indicates that the  
82546GB/EB uses INTB#.  
4
Interrupt Pin  
If only a single device/function of the Ethernet controller is enabled, this  
value is ignored and the Interrupt Pin field of the enabled device reports  
INTA# usage.  
Set this bit to 0b (default) to enable the FLASH logic.  
Set this bit to 1b to disable the FLASH logic. Note that the Expansion  
ROM & secondary FLASH access BARs in PCI configuration space are  
also disabled.  
3
2
FLASH Disable  
APM Enable  
Initial value of Advanced Power Management Wakeup Enable in the  
Wakeup Control Register (WUC.APME).  
The default for this bit is 0b.  
Initial value of Link Mode bits of the Extended Device Control Register  
(CTRL_EXT.LINK_MODE), specifying which link interface and protocol  
is used by the MAC.  
For Address 24h (High Byte) / LAN A  
00b = MAC operates in GMII/MII mode with internal copper PHYa  
01b = External GMII/MII mode  
10b = Internal SerDes mode (not applicable to the 82540EP/EM)  
11b = MAC operates in TBI mode using external TBI interface  
For Address 14h (High Byte) / LAN B  
1:0  
Link Mode  
00b = MAC operates in GMII/MII mode with internal copper PHY  
01b = Reserved  
10b = Internal SerDes mode (not applicable to the 82540EP/EM)  
11b = MAC operates in TBI mode using external TBI interface  
a.  
For the 82540EP/EM, 82541PI/GI/EI, and 82547GI/EI to properly communicate with the internal copper PHY, this value  
must be set to 00b.  
Note: Since the 82546GB/EB is a dual-port device, the Initialization Control Word 3 bit assignments are  
port specific.  
1. Applicable to the 82546GB/EB only.  
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5.6.27  
IPv4 Address (Words 15h - 16h1 and 25h - 26h)  
The following table lists the initial values for the IPv4 addresses.  
Table 5-13. IPv4 Addresses  
Bit  
Name  
Description  
The initial value of IPv4 Address Table entry 0. (IP4AT[0]).  
31:0  
IPv4 Address  
Refer to the EEPROM Address Map listed in Table 5-2 for an indication  
of how the bytes are stored.  
Note: Since the 82546GB/EB is a dual-port device, the IPv4 Address in 15h-16h corresponds to LAN B,  
and the IPv4 Address in 25h-26h corresponds to LAN A.  
5.6.28  
IPv6 Address (words 17h - 1Eh1 and 27h - 2Eh)  
The following table lists the initial values for the IPv6 addresses.  
Table 5-14. IPv6 Address  
Bit  
Name  
Description  
The initial value of IPv6 Address Table entry 0. (IP6AT[0])  
127:0  
IPv6 Address  
Refer to the EEPROM Address Map listed in Table 5-2 for an indication  
of how the bytes are stored.  
Note: Since the 82546GB/EB is a dual-port device, the IPv6 Address in 17h-1Eh corresponds to LAN B,  
and the IPv6 Address in 27h-2Eh corresponds to LAN A.  
1. Applicable to the 82546GB/EB only.  
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5.6.29  
LED Configuration Defaults (Word 2Fh)1  
This EEPROM word specifies the hardware defaults for the LEDCTL register fields controlling the  
LED0/(LINK_UP#) and LED2/LINK100 output behaviors. Refer to Table 13-60 for the LED  
Control bit descriptions and Table 13-61 for the Mode Encodings.  
Note: A value of 0602h is used to configure default hardware LED behavior equivalent to 82544-based  
Copper adapters (LED0/LINK_UP#, LED1/ACTIVITY# (blinking), LED2/LINK100#, and  
LED3/LINK1000#).  
Table 5-15. LED Configuration Defaults  
Bit  
Name  
Description  
Initial value of the LED0_MODE field specifying what event/state/  
pattern will be displayed on LED0 (LINK_UP) output. A value of  
0010 (0x2) causes this to indicate LINK_UP state.  
3:0  
LED0 Mode  
Reserved.  
Set as 0b.  
5:4  
6
Reserved  
Initial value of LED0_IVRT field.  
0b = Active-low output.  
LED0 Invert  
LED0 Blink  
Initial value of LED0_BLINK field.  
0b = Non-blinking.  
7
Initial value of the LED2_MODE field specifying what event/state/  
pattern will be displayed on LED2 (LINK_100) output. A value of  
0110b (0x6) causes this to indicate 100 Mb/s operation.  
11:8  
LED2 Mode  
13:12  
14  
Reserved  
Reserved. Set as 0b.  
Initial value of LED2_IVRT field.  
0b = Active-low output.  
LED2 Invert  
Initial value of.LED2_BLINK field.  
0b = Non-blinking  
15  
LED2 Blink  
5.6.30  
Boot Agent Main Setup Options (Word 30h)  
The boot agent software configuration is controlled by the EEPROM with the main setup options  
stored in word 30h. These options are those that can be changed by using the Control-S setup menu  
or by using the IBA Intel Boot Agent utility.  
Note: The 82541ER does not support the Intel Boot Agent functionality.  
1. Not applicable to the 82544GC/EI.  
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Table 5-16. Boot Agent Main Setup Options  
Bit  
Name  
Description  
PXE Presence.  
Setting this bit to 0b Indicates that the image in the FLASH contains a  
PXE image.  
Setting this bit to 1b indicates that no PXE image is contained.  
15  
PPB  
The default for this bit is 0b in order to be backwards compatible with  
existing systems already in the field.  
If this bit is set to 0b, EEPROM word 32h (PXE Version) is valid. When  
EPB is set to 1b and this bit is set to 0b, indicates that both images are  
present in the FLASH.  
EFI Presence.  
Setting this bit to 1b Indicates that the image in the FLASH contains an  
EFI image.  
Setting this bit to 0b indicates that no EFI image is contained.  
14  
EPB  
The default for this bit is 0b in order to be backwards compatible with  
existing systems already in the field.  
If this bit is set to 1b, EEPROM word 33h (EFI Version) is valid. When  
PPB is set to 0b and this bit is set to 1b, indicates that both images  
(PXE and EFI) are present in the FLASH.  
13  
12  
Reserved  
FDP  
Reserved for future use. Set this bit to 0b.  
Force Full Duplex.  
Set this bit to 0b for half duplex; set to 1b for full duplex.  
Note that this bit is a don’t care unless bits 10 and 11 are set.  
These bits determine speed. 01b = 10 Mbs, 10b = 100 Mbs, 11b = Not  
allowed.  
11:10  
FSP  
All zeros indicate Auto-negotiate (the current bit state).  
Note that bit 12 is a don’t care unless these bits are set.  
9
8
Reserved  
DSM  
Reserved for future use. Set this bit to 0b.  
Display Setup Message.  
If this bit is set to 1b, the "Press Control-S" message appears after the  
title message.  
The default for this bit is 1b.  
Prompt Time. These bits control how long the "Press Control-S" setup  
prompt message appears, if enabled by DIM.  
00b = 2 seconds (default)  
01b = 3 seconds  
7:6  
PT  
10b = 5 seconds  
11b = 0 seconds  
Note that the Ctrl-S message does not appear if 0 seconds prompt time  
is selected.  
Local Boot Selection (OBSOLETE). In previous versions of the agent,  
this bit enables or disables local boot, if the DBS bit selects it.  
5
LBS  
The default for this bit is 1b; enable local booting. The boot agent, at  
runtime, no longer uses this bit.  
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Table 5-16. Boot Agent Main Setup Options  
Bit  
Name  
Description  
Default Boot Selection. These bits select which device is the default  
boot device. These bits are only used if the agent detects that the BIOS  
does not support boot order selection or if the MODE field of word 31h  
is set to MODE_LEGACY.  
4:3  
DBS  
00b = Network boot, then local boot  
01b = Local boot, then network boot  
10b = Network boot only  
11b = Local boot only  
BIOS Boot Specification (OBSOLETE). In previous versions of the  
agent, this bit enables or disables use of the BBS to determine boot  
order. If set to 1b, the BIOS boot order is used, and the DBS bits are  
ignored. The boot agent at runtime no longer uses this bit. The runtime  
checks for BBS/PnP and the setting in the MODE field of word 31h are  
used instead.  
2
BBS  
PS  
Protocol Select. These bits select the boot protocol.  
00b = PXE (default value)  
1:0  
01b = RPL protocol  
Other values are undefined.  
5.6.31  
Boot Agent Configuration Customization Options (Word  
31h)  
Word 31h contains settings that can be programmed by an OEM or network administrator to  
customize the operation of the software. These settings cannot be changed from within the Control-  
S setup menu or the IBA Intel Boot Agent utility. The lower byte contains settings that would  
typically be configured by a network administrator using the Intel Boot Agent utility; these settings  
generally control which setup menu options are changeable. The upper byte are generally settings  
that would be used by an OEM to control the operation of the agent in a LOM environment,  
although there is nothing in the agent to prevent their use on a NIC implementation  
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.
Table 5-17. Boot Agent Configuration Customization Options (Word 31h)  
Bit  
15:14  
13:11  
Name  
Description  
Signature. These bits must be set to 1b to indicate that this word has  
been programmed by the agent or other configuration software.  
SIG  
Reserved  
Reserved for future use. Set these bits to 0b.  
Selects the agent's boot order setup mode. This field changes the  
agent's default behavior in order to make it compatible with systems  
that do not completely support the BBS and PnP Expansion ROM  
standards. Valid values and their meanings are:  
000b - Normal behavior. The agent attempts to detect BBS and PnP  
Expansion ROM support as it normally does.  
001b - Force Legacy mode. The agent does not attempt to detect BBS  
or PnP Expansion ROM supports in the BIOS and assumes the BIOS is  
not compliant. The BIOS boot order can be changed in the Setup  
Menu.  
010b - Force BBS mode. The agent assumes the BIOS is BBS-  
compliant, even though it may not be detected as such by the agent's  
detection code. The BIOS boot order CANNOT be changed in the  
Setup Menu.  
10:8  
MODE  
011b - Force PnP Int18 mode. The agent assumes the BIOS allows  
boot order setup for PnP Expansion ROMs and hooks interrupt 18h (to  
inform the BIOS that the agent is a bootable device) in addition to  
registering as a BBS IPL device. The BIOS boot order CANNOT be  
changed in the Setup Menu.  
100b - Force PnP Int19 mode. The agent assumes the BIOS allows  
boot order setup for PnP Expansion ROMs and hooks interrupt 19h (to  
inform the BIOS that the agent is a bootable device) in addition to  
registering as a BBS IPL device. The BIOS boot order CANNOT be  
changed in the Setup Menu.  
101b - Reserved for future use. If specified, treated as value 000b.  
110b - Reserved for future use. If specified, treated as value 000b.  
111b - Reserved for future use. If specified, treated as value 000b.  
7:6  
5
Reserved  
DFU  
Reserved for future use. Set these bits to 0b.  
Disable FLASH Update.  
If set to 1b, no updates to the FLASH image using PROSet is allowed.  
The default for this bit is 0b; allow FLASH image updates using  
PROSet.  
Disable Legacy Wakeup Support.  
If set to 1b, no changes to the Legacy OS Wakeup Support menu  
option is allowed.  
4
3
DLWS  
DBS  
The default for this bit is 0b; allow Legacy OS Wakeup Support menu  
option changes.  
Disable Boot Selection.  
If set to 1b, no changes to the boot order menu option is allowed.  
The default for this bit 0b; allow boot order menu option changes.  
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Table 5-17. Boot Agent Configuration Customization Options (Word 31h)  
Bit  
Name  
Description  
Disable Protocol Select.  
2
1
DPS  
DTM  
If set to 1b, no changes to the boot protocol is allowed.  
The default for this bit is 0b; allow changes to the boot protocol.  
Disable Title Message.  
If set to 1b, the title message displaying the version of the boot agent is  
suppressed; the Control-S message is also suppressed. This is for  
OEMs who do not wish the boot agent to display any messages at  
system boot.  
The default for this bit is 0b; allow the title message that displays the  
version of the boot agent and the Control-S message.  
Disable Setup Menu.  
If set to 1b, no invoking the setup menu by pressing Control-S is  
allowed. In this case, the EEPROM can only be changed via an  
external program.  
0
DSM  
The default for this bit is 0b; allow invoking the setup menu by pressing  
Control-S.  
5.6.32  
Boot Agent Configuration Customization Options (Word  
32h)  
Word 32h is used to store the version of the boot agent that is stored in the FLASH image. When  
the Boot Agent loads, it can check this value to determine if any first-time configuration needs to  
be performed. The agent then updates this word with its version. Some diagnostic tools to report  
the version of the Boot Agent in the FLASH also read this word. This word is only valid if the PPB  
is set to 0b. Otherwise the contents might be undefined.  
Table 5-18. Boot Agent Configuration Customization Options (Word 32h)  
Bit  
15:12  
11:8  
Name  
Description  
MAJOR  
MINOR  
BUILD  
PXE boot agent major version. The default for these bits is 0b.  
PXE boot agent minor version. The default for these bits is 0b.  
PXE boot agent build number. The default for these bits is 0b.  
7:0  
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5.6.33  
IBA Capabilities (Word 33h)  
Word 33h is used to enumerate the boot technologies that have been programmed into the FLASH.  
It is updated by IBA configuration tools and is not updated or read by IBA.  
Table 5-19. IBA Capabilities  
Bit  
15:14  
13:5  
Name  
Description  
Signature. These bits must be set to 1b to indicate that this word has  
been programmed by the agent or other configuration software.  
SIG  
Reserved  
Reserved for future use. Set these bits to 0b.  
SAN capability is present in FLASH.  
4
3
2
1
0
SAN  
EFI  
0b = The SAN capability is not present (default).  
1b = The SAN capability is present.  
EFI UNDI capability is present in FLASH.  
0b = The RPL code is not present (default).  
1b = The RPL code is present.  
RPL capability is present in FLASH.  
1b = The RPL code is present (default).  
0b = The RPL code is not present.  
RPL  
UNDI  
BC  
PXE/UNDI capability is present in FLASH.  
1b = The PXE base code is present (default).  
0b = The PXE base code is not present.  
PXE base code is present in FLASH.  
0b = The PXE base code is present (default).  
1b = The PXE base code is not present.  
5.6.34  
IBA Secondary Port Configuration (Words 34h-35h)  
These words provide a unique configuration for the second port of the 82546GB/EB. The format is  
the same as that used in words 30h and 31h for LAN A.  
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5.6.35  
Checksum Word Calculation (Word 3Fh)  
The Checksum word (3Fh) should be calculated such that after adding all the words (00h-3Fh),  
including the Checksum word itself, the sum should be BABAh. The initial value in the 16-bit  
summing register should be 0000h and the carry bit should be ignored after each addition. This  
checksum is not accessed by the Ethernet controller. If CRC checking is required, it must be  
performed by software.  
Note: Hardware does not calculate checksum word 3Fh during EEPROM write; it must be calculated by  
software independently and included in the EEPROM write data. Hardware does not compute a  
checksum over words 00h-0Fh during EEPROM reads in order to determine the validity of the  
EEPROM image; this field is provided strictly for software verification of EEPROM validity. All  
hardware configuration based on word 00h-0Fh content is based on the validity of the Signature  
field of EEPROM Initialization Control Word 1. Signature must be 01b.  
5.6.36  
82546GB/EB Dual-Channel Fiber Wake on LAN (WOL) Mode  
and Functionality (Word 0Ah, 20h)  
Four bits and two words determine dual-channel fiber WOL mode and functionality. In addition to  
the power management bits, one of the SDP’s must be set in order for the “A” laser to remain on  
when the system goes into D3. Three states are defined for the EEPROM image:  
• Never - The Ethernet controller has WOL disabled and cannot be put into WOL mode.  
• Possible - The Ethernet controller can be WOL enabled, but currently has the feature turned  
off. This is the normal shipping configuration for WOL-capable server adapter cards.  
• On - The Ethernet controller is set with WOL functionality enabled.  
Table 5-20. WOL Mode and Functionality (Word 0Ah)  
State  
Never  
Bit 2  
Bit 7  
Resulting Word  
4C03  
0
1
1
0
0
1
Possible  
On  
4C0B  
4C2B  
Table 5-21. WOL Mode and Functionality (Word 20h)  
State  
Never  
Bit 2  
Bit 7  
Resulting Word  
C109  
0
1
1
0
0
1
Possible  
On  
C10D  
C18D  
5.6.37  
EEPROM Images  
Refer to the appropriate Ethernet controller’s EEPROM map and programming information for  
sample EEPROM images.  
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EEPROM Interface  
5.7  
Parallel FLASH Memory  
All Ethernet controllers except the 82540EP/EM provide an external parallel interface to an  
optional FLASH or boot EEPROM device. Accesses to the FLASH memory are controlled by the  
Ethernet controllers, but are accessible to host software as normal PCI reads or writes to the  
FLASH memory mapping range. Software developers can also map FLASH memory to I/O space.  
The Ethernet controllers support 8-bit wide parallel FLASH memory up to 4 Mb (512 KB); an  
appropriate size for typical applications would be 1 Mb (128 KB). The size of the FLASH  
implemented in the design can be encoded into bits in the EEPROM. FLASH and expansion ROM  
base address registers are reconfigured based on these EEPROM settings.  
Representative FLASH memory devices that have been found to work satisfactorily with the  
Ethernet controllers are listed in Table 5-22:  
Table 5-22. FLASH Memory Manufacturers  
Manufacturer’s Part  
Manufacturer  
Number  
AT49LV010  
Atmel  
AT49BV002AN-70J1  
SST39V512  
Silicon Storage  
39VF020-90-4I-NH  
Technology  
39VF020-70-4C-NH  
The FLASH memory interface trace routing is not critical because the interface runs at a very slow  
speed. In a tightly space-constrained design, the FLASH memory device is a good choice for  
placement in relative isolation from the Ethernet controllers.  
Note: The 82540EP/EM provides an external interface to a serial FLASH or Boot EEPROM device. See  
Appendix B for more information.  
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FLASH Memory Interface  
7
All Ethernet controllers (except the 82540EP/EM) provide an external parallel interface to a  
1
FLASH, or boot ROM, device such as the Atmel AT49LV010 . All accesses to this device are  
managed by the Ethernet controller and are accessible to software as normal PCI reads or writes to  
the FLASH memory mapping range. The Ethernet controller supports parallel FLASH devices  
with up to 4 Mb (512 KB) of memory. The size of the FLASH implemented with the Ethernet  
controller can be encoded into bits in the EEPROM. The FLASH and Expansion ROM Base  
Address Registers are reconfigured based on these EEPROM settings.  
Note: Though the Ethernet controller supports devices with up to 512 KB of memory, smaller devices can  
also be used. Accesses to memory beyond the FLASH device size results in access wrapping as  
only the lower address bits are utilized by the FLASH.  
7.1  
FLASH Interface Operation  
The FLASH is read from, or written to, each time the host processor performs a read or a write  
operation to a memory location that is within the FLASH address mapping or upon boot through  
accesses in the space indicated by the Expansion ROM Base Address Register (see Section 4.1).  
All accesses to the FLASH, except read accesses, require the appropriate command sequence for  
the device used. Refer to the specific FLASH data sheet for more details on reading from or writing  
to FLASH. Accesses to the FLASH are based on a direct decode of processor accesses to a memory  
window defined in either the Ethernet controller's FLASH Base Address Register (PCI Control  
Register at offset 14h or 18h) or the Expansion ROM Base Address Register (PCI Control Register  
at offset 30h).  
FLASH accesses must always be assembled or disassembled by the Ethernet controller to or from  
the FLASH whenever the access is greater than a byte-wide access. Due to slow access times to a  
typical FLASH, word (32-bit) accesses are not recommended for any cycles that occur after system  
initialization in order to avoid violating PCI hold specifications. Boot ROM shadowing is an  
exception to the 16 clock rule and can incur in excess of 25 wait states. The Ethernet controller byte  
reads to the FLASH take approximately of 256 ns. The Ethernet controller issues retry accesses  
during this time.  
7.2  
FLASH Control and Accesses  
Write control of the FLASH is controlled by the FWE bits in the EEPROM/FLASH Control and  
Data Register (EECD.FWE). See Section 13.4.3 for details.  
Processor accesses to the FLASH are very slow. The Ethernet controller always issues a target-  
disconnect at the first data cycle. The Ethernet controller asserts the STOP# signal to indicate the  
target-disconnect. Section 7.2.1 and Figure 7.2.2 show read and write accesses to the FLASH. Note  
that burst accesses to the FLASH address space are not allowed.  
1. The 82540EP/EM provides an external interface to a serial FLASH or Boot EEPROM device. See Appendix B for more information.  
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FLASH Memory Interface  
7.2.1  
Read Accesses  
Upon reads to the FLASH address space, the Ethernet controller uses the TRDY# signal to insert  
target wait states until valid data can be read from the FLASH device and presented on the data  
lines. When TRDY# is asserted, the Ethernet controller drives valid data on the data lines. The  
processor master can then complete normal data read cycle by asserting IRDY# when it is ready.  
CLK  
1
2
3
4
5
6
7
8
9
FRAME#  
AD  
ADDRESS  
MEM-RD  
DATA  
CBE#  
IRDY#  
BE#s  
TRDY#  
DEVSEL#  
STOP#  
Figure 7-1. FLASH Buffer Read Cycles  
7.2.2  
Write Accesses  
The processor, as the initiator, drives the address lines AD[63:0], the command and byte enable  
lines [7:0]#, and the control lines IRDY# and FRAME#. It also provides the Ethernet controller  
with valid data immediately after asserting TRDY#. The Ethernet controller controls the TRDY#  
signal and deasserts it for a certain number of clocks until valid data is written to the FLASH  
buffer. By asserting TRDY#, the Ethernet controller signals the processor that the current data  
phase has completed.  
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CLK  
FRAME#  
AD  
1
2
3
7
8
9
10  
11  
12  
13  
14  
ADDRESS  
MEM-WR  
DATA  
BE#s  
CBE#  
IRDY#  
TRDY#  
DEVSEL#  
STOP#  
Figure 7-2. FLASH Buffer Write Cycle  
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Power Management  
6
6.1  
Introduction to Power Management  
The PCI/PCI-X Family of Gigabit Ethernet Controllers support the Advanced Configuration and  
Power Interface (ACPI) specification as well as Advanced Power Management (APM). This  
section describes how Power Management is implemented in the Ethernet controllers.  
Note: The 82541ER does not support ACPI or APM wakeup.  
Power Management can be disabled via bits in the Initialization Control Word 2 which is loaded  
from the EEPROM during power-up reset. See the EEPROM description in Section 5.6.12 for  
further details. Even when disabled, the Power Management register set is still present.  
The Ethernet controller supports the following Power Management related features:  
• Power states of D0 & D3 with optional D3  
support  
hot  
cold  
• Power(D3) < Power(D0)  
• Wakeup  
6.2  
Assumptions  
The following assumptions apply to the implementation of Power Management for the Ethernet  
controller.  
• Any time LAN_PWR_GOOD is asserted all power supplies are stable, RST# is stable, and the  
clock is stable.  
• Prior to transition from D0 to the D3 state, the operating system ensures that the software  
device driver is disabled and all pending bus transactions are complete or cleanly terminated.  
• The driver sets up the filters prior to the system transitioning the Ethernet controller to the D3  
state.  
1
• The system never deactivates the PCI clock in 66 MHz PCI mode or any PCI-X mode without  
asserting RST#.  
• No wakeup capability, except APM Wakeup if enabled in the EEPROM, is required after the  
system asserts, then de-asserts RST#.  
• No wakeup capability, except APM Wakeup if enabled in the EEPROM, is required after the  
system puts the Ethernet controller in the D3 state and then returns it to D0.  
• If the APMPME bit (bit 3) in the Wakeup Control Register (WUC.APMPME) is set to 1b, it is  
permissible to assert PME# even when PME_En is 0b.  
• The deassertion (rising) edge of RST# puts the Ethernet controller in the D0u state.  
1. The 82540EP/EM, 82541xx, and 82547GI/EI do not support PCI-X mode.  
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6.3  
D3  
support  
cold  
If the AUX pin is connected to logic 1b, the Ethernet controller advertises D3  
Wakeup support.  
cold  
The amount of power required for this function (which includes the entire Ethernet port circuitry)  
is advertised in the Power Management Data Register which is loaded from the EEPROM.  
If D3  
is supported, the PME_En and PME_Status bits of the Power Management Control/Status  
cold  
Register (PMCSR), as well as their shadow bits in the Wakeup Control Register (WUC) are not  
reset by RST#. If D3 Wakeup is not supported, PMCSR and WUC is reset on the deassertion  
cold  
(rising edge) of RST#.  
The only effect of setting AUX to 1b is advertising D3  
Wakeup support and changing the reset  
cold  
function of PME_En and PME_Status. The 82541PI/GI can enter a fully-disabled low-power state  
in D3 if an enable bit is set in the EEPROM. All remaining Ethernet controllers do nothing  
cold  
different in D3  
compared to D3 . AUX_POWER is level sensitive, and any changes are  
hot  
cold  
immediately reflected in the D3  
reset function.  
Wakeup advertisements and the PME_En and PME_Status  
cold  
6.3.1  
Power States  
The Ethernet controller supports D0 and D3 power states defined in the PCI Power Management  
Specification. D0 is divided into two sub-states: D0u, and D0a. In addition, it supports a Dr state  
that is entered when RST# is asserted. Dr behaves the same as D3 except that the PCI bus is  
isolated. Figure 6-1 illustrates the power states and the conditions that cause transitions from state  
to state.  
LAN_POWER_GOOD  
assertion  
RST#  
deassertion  
Dr*  
D0u  
RST# assertion  
RST#  
assertion  
Enable Memory  
Access  
Write 00b  
to Power  
State  
RST#  
assertion  
D3  
D0a  
Write 11b to  
Power State  
*equivalent to D3 except PCI pins are floated  
Figure 6-1. Power State Transitions  
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6.3.1.1  
Dr State  
At initial boot-up, once LAN_PWR_GOOD is asserted, the Ethernet controller reads the  
EEPROM. If the APM Mode bit in the EEPROM’s Initialization Control Word 2 is set then APM  
Wakeup is enabled.  
The system may maintain RST# asserted for an arbitrary time. During this time, and for up to 1 ms  
afterwards, the Ethernet controller does not assert any PCI signals except PME#.  
During operation, the system may assert RST# at any time. In particular, if the system wishes an  
Ethernet controller to enter the D3cold state it must assert RST# before dropping main power. Any  
time RST# is asserted, the Ethernet controller transitions to the Dr state. It also floats all PCI  
signals except PME# and remains in the “reset” state until no more than 1 ms after the deassertion  
of RST#.  
Internally, the Ethernet controller treats the reset state equivalently to D3. Any Wakeups enabled  
before entering reset is maintained. For power savings, the Ethernet controller shuts down some  
internal clocks and registers and deasserts PWR_STATE1. If Wakeup is not enabled, the Ethernet  
controller also deasserts PWR_STATE0. As a result, the Ethernet controller won’t transmit any  
frames in Dr state or send idles in TBI mode (82544GC/EI)/internal SerDes (82546GB/EB and  
1
82545GM/EM) .  
The deassertion (rising edge) of RST# causes a transition to D0u.  
6.3.1.2  
D0u State  
The D0u state is a low-power state used after RST# is deasserted, or when coming out of D3, but  
before the Ethernet controller is initialized.  
When entering D0u, the Ethernet controller disables Wakeups, resets the PHY, and then re-reads  
the EEPROM. If the APM Mode bit in the EEPROM’s Initialization Control Word 2 is set, then  
APM Wakeup is enabled.  
Internally, D0u is treated like D3 and some internal clocks and registers are shut down. The D0u  
state is exited when the system enables memory space access to the Ethernet controller by writing a  
1b to the Memory Access Enable bit of the PCI Command Register.  
Note: In order for hardware to transition from D3 to the D0 state properly, BIOS should not alter the  
Memory Access Enable or the I/O Access Enable bit of the PCI Command Register. Also, the PCI  
configuration space must be programmed when hardware transitions out of D3 to D0.  
1. Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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Power Management  
6.3.1.3  
D0a (D0 active)  
Once memory space is enabled, all internal clocks are activated, the Ethernet controller enters an  
active state, and can then transmit and receive packets if properly configured by the software  
driver. The controller also signals the PHY (if using the internal PHY) to indicate full speed/  
1
power . If APM Wakeup was activated it remains active. The software driver can deactivate APM  
Wakeup by writing to the Wakeup Control Register (WUC), or activate other Wakeup Filters by  
writing to the Wakeup Registers.  
6.3.1.4  
D3  
Prior to transition from D0 to the D3 state, the software driver must ensure the Ethernet controller  
transmit and receive functions have been disabled and all pending bus transactions are complete or  
cleanly terminated. If Wakeup capability is needed, the software driver needs to set up the  
appropriate Wakeup registers and the system needs to write a 1b to the PME_En bit of the Power  
Management Control / Status Register (PMCSR) prior to the transition to D3.  
When the system writes a 11b to the PowerState field of the Power Management Control/Status  
Register (PMCSR) the Ethernet controller transitions to D3. Any Wakeups that are enabled remain  
enabled. Upon transitioning to D3 the Ethernet controller clears the Memory Access Enable or the  
I/O Access Enable bit of the PCI Command Register, which disables memory access decode. In  
D3, the Ethernet controller only responds to PCI configuration accesses. It won’t generate master  
2
cycles, transmit any frames on the TBI/internal SerDes /internal PHY interface, or transmit idles in  
TBI mode/internal SerDes if Wakeup is enabled.  
For power savings the Ethernet controller shuts down some internal clocks and registers.  
To transition back to D0u, the system writes a 00b to the Power State field of the Power  
Management Control/Status Register (PMCSR).  
6.3.2  
Timing  
The following sections give detailed timing for the state transitions. In the diagrams the dotted  
connecting lines represent the Ethernet controller’s requirements, while the solid connecting lines  
represent the Ethernet controller’s guarantees.  
Note: The following timing diagrams are not to scale. The clocks edges are shown to indicate running  
clocks only and are not used to indicate the actual number of cycles for any operation.  
If CLK_RUN# functionality is enabled in the EEPROM, then the 82541PI/GI/EI and 82540EP  
Ethernet controllers assert the CLK_RUN# pin when it requires the PCI clock. Otherwise, the  
clock is not required and the system might shut the PCI clock off.  
1. Not applicable to the 82541xx or 82547GI/EI.  
2. Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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6.3.2.1  
Power Up (Off to Dr to D0u to D0a)  
Power  
1
LAN_POWER_GOOD  
CLK#  
RST#  
5
4
8
9
Memory Access  
2
Reading EEPROM  
Read EEPROM  
Read EEPROM  
7
PCI Pins  
Running  
Wakeup Enabled  
APM Wakeup  
APM Wakeup  
3
6
PWR_STATE[1:0]  
82544GC/EI Only  
00b  
00b if wakeup is disabled, 10b if wakeup is enabled  
Dr  
11b  
DState  
D0u  
D0a  
Figure 6-2. Startup Timing  
Diagram #  
Notes  
1
2
3
4
LAN_PWR_GOOD must not be asserted until all power supplies are good and the clock is stable.  
An EEPROM read starts on the rising edge of LAN_PWR_GOOD and RST#.  
APM Wakeup mode can be enabled based on what is read from the EEPROM.  
The system can delay an arbitrary time before deasserting RST#.  
The PCI 2.2 or 2.3 specification requires the clock to be active 100 µs before deasserting RST#. (Tclk-rst  
parameter)  
5
6
7
8
The deassertion edge of RST# causes the EEPROM to be re-read and Wakeup disabled.  
Synchronizing the clock generators and circuit adjustments require up to 512 PCI clocks before the Ethernet  
controller drives PCI signals and responds to PCI transactions.  
The system can delay an arbitrary time before enabling Memory Access.  
Writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command Register transitions the  
Ethernet controller from D0u to D0 state.  
9
For the 82544GC/EI, writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command  
Register transitions the Ethernet controller from D0u to D0 state and asserts both PWR_STATE outputs.  
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6.3.2.2  
Transition From D0a to D3 and Back Without PCI Reset  
I_PCI_CLK  
RST#  
D0 Write  
3
6
2
7
Memory Access Enable  
Reading EEPROM  
Read EEPROM  
D3 write  
1
PCI Pins  
Running  
Wakeup Enabled  
4
Any mode  
APM only  
D0u  
5
PWR_STATE[1:0]  
82544GC/EI Only  
11b  
00b if wakeup is disabled, 01b if wakeup is enabled  
D3  
00b/01b  
11b  
DState D0a  
D0  
Figure 6-3. Transition from D0a to D3 and Back Without PCI Reset  
Diagram # Notes  
Writing a 11b to the Power State field of the Power Management Control/Status Register (PMCSR) transitions  
the Ethernet controller to D3.  
1
2
3
The system can keep the Ethernet controller in D3 state for an arbitrary amount of time.  
To exit D3 state the system writes 00b to the Power State field of the Power Management Control/Status  
Register (PMCSR).  
4
5
6
APM Wakeup mode can be enabled based on what is read in the EEPROM.  
For the 82544GC/EI, PWR_STATE[1:0] is set to 01b if APM Wakeup is enabled, 00b otherwise.  
The system can delay an arbitrary time before enabling memory access.  
Writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command Register transitions  
the Ethernet controller from D0u to D0 state.  
7
For the 82544GC/EI, writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command  
Register transitions the Ethernet controller from D0u to D0 state and asserts both PWR_STATE outputs.  
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6.3.2.3  
Transition From D0a to D3 and Back with PCI Reset  
CLK#  
5
3
RST#  
9
6
10  
2
4
Memory Access Enable  
Reading EEPROM  
Read EEPROM  
D3 write  
1
7
8
PCI Pins  
Running  
Wakeup Enabled  
Any mode  
APM Wakeup  
PWR_STATE[1:0]  
11b  
00b if wakeup is disabled, 01b if wakeup is enabled  
Dr  
00b/01b  
11b  
82544GC/EI Only  
DState  
D3  
D0u  
D0a  
D0a  
Figure 6-4. Transition From D0a to D3 and Back with PCI Reset  
Diagram #  
Notes  
Writing a 11b to the Power State field of the Power Management Control/Status Register (PMCSR) transitions  
the Ethernet controller to D3.  
1
2
The system can delay an arbitrary amount of time between setting D3 mode and asserting RST#.  
In 66 MHz or PCI-Xa modes the system must assert RST# before stopping the PCI clock. It may assert RST#  
without stopping the clock.  
3
For the 82541PI/GI/EI and 82540EP, If CLK_RUN# is enabled, then they do not require a continuous clock  
during this time, but does require that the system drive the clock in response to CLK_RUN# assertion.  
4
5
Upon assertion of RST# the Ethernet controller floats all PCI pins except PME# and goes to “Dr” state.  
In 66 MHz or PCI-X modes, the PCI 2.2 and 2.3 specification requires the system to start the PCI clock 100 µs  
before deassertion of RST#. In 33 MHz systems the PCI clock can start and stop at any time independent of  
RST#.  
6
7
The deassertion edge of RST# causes the EEPROM to be re-read and Wakeup disabled.  
Synchronizing the clock circuits and circuit adjustments require up to 512 PCI clocks before the Ethernet  
controller drives PCI signals and responds to PCI transactions.  
8
9
For the 82544GC/EI, O_PWR_STATE is set to 01b if APM Wakeup is enabled, 00b otherwise.  
The system can delay an arbitrary time before enabling memory access.  
Writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command Register transitions  
the Ethernet controller from D0u to D0 state.  
10  
For the 82544GC/EI, writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command  
Register transitions the Ethernet controller from D0u to D0 state and asserts both PWR_STATE outputs.  
a.  
Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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6.3.2.4  
PCI Reset Without Transition to D3  
CLK#  
RST#  
3
1
2
7
4
8
Memory Access Enable  
Reading EEPROM  
Read EEPROM  
5
6
PCI Pins  
Running  
Running  
Wakeup Enabled  
Any mode  
APM Wakeup  
PWR_STATE[1:0]  
11b  
00b if wakeup is disabled, 01b if wakeup is enabled  
Dr  
00b/01b  
D0u  
11b  
82544GC/EI Only  
DState  
D0a  
D0a  
Figure 6-5. PCI Reset Sequence  
Diagram #  
Notes  
In 66 MHz or PCI-Xa modes, the system must assert RST# before stopping the PCI clock. It may assert RST#  
without stopping the clock.  
1
2
Upon assertion of RST# the Ethernet controller floats all PCI pins except PME# and goes to “Dr” state.  
In 66 MHz or PCI-X modes the system must assert RST# before stopping the PCI clock. It may assert RST#  
without stopping the clock.  
3
For the 82541PI/GI/EI and 82540EP, If CLK_RUN# is enabled, then they do not require a continuous clock  
during this time, but does require that the system drive the clock in response to CLK_RUN# assertion.  
4
5
The deassertion edge of RST# caused the EEPROM to be re-read and Wakeup disabled.  
Synchronizing the clock circuits and circuit adjustments require up to 512 PCI clocks before the Ethernet  
controller drives PCI signals and responds to PCI transactions.  
6
7
For the 82544GC/EI, PWR_STATE[1:0] is set to 01b if APM Wakeup is enabled, 00b otherwise.  
The system can delay an arbitrary time before enabling memory access.  
Writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command Register transitions  
the Ethernet controller from D0u to D0 state.  
8
For the 82544GC/EI, writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI  
Command Register transitions the Ethernet controller from D0u to D0 state and asserts both PWR_STATE  
outputs.  
a.  
Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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Power Management  
6.3.3  
PCI Power Management Registers  
Power Management registers are part of the capabilities linked list pointed to by the Capabilities  
Pointer (Cap_Ptr) in the PCI configuration space. Refer to Section 4.1.  
All fields are reset by LAN_PWR_GOOD. All of the fields except PME_En and PME_Status are  
reset by the deassertion (rising edge) of RST#. If AUX_POWER = 0b, the PME_En and  
PME_Status fields also reset by the deassertion (rising edge) of RST#.  
The following table lists the organization of the PCI Power Management Register Block:  
Byte Offset  
Byte 3  
Byte 2  
Byte 1  
Byte 0  
Power Management Capabilities  
(PMC)  
DCh  
Next Item Ptr  
Capability ID  
PMCSR_BSE  
Bridge Support  
Extensions  
Power Management Control / Status  
Register (PMCSR)  
E0h  
Data  
The following sections describe the register definitions, whether they are required or optional for  
compliance, and how they are implemented in the Ethernet controller. Complete details can be  
found in the PCI Power Management Interface specification.  
Note: The offset indicated is the byte-offset from the position indicated by Cap_Ptr in the Configuration  
Space Header.  
6.3.3.1  
Capability ID  
1 Byte Offset = 0 (RO)  
Bits  
Default  
01h  
R/W  
Description  
Read  
Only  
ID – The Ethernet controller returns a value of 01h for this field, indicating  
the linked list item as being the PCI Power Management Registers.  
07:00  
6.3.3.2  
Next Item Pointer  
1 Byte Offset = 1 (RO)  
Bits  
Default  
R/W  
Description  
Next Item Pointer - This field provides an offset into the function’s PCI  
Configuration Space pointing to the location of next item in the function’s  
capability list. Its value of E4h points to the PCI-Xa capability.  
Read  
Only  
07:00  
E4h  
a.  
Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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6.3.3.3  
Power Management Capabilities - (PMC)  
2 Bytes Offset = 2 (RO)  
Bits  
Default  
R/W  
Description  
PME_Support – This 5-bit field indicates the power states in which the  
function may assert PME#a. A value of 0b for any bit indicates that the  
function is not capable of asserting the PME# signal while in that power  
state.  
bit (11) (XXXX1)b – PME# can be asserted from D0  
bit (12) (XXX1X)b – PME# can be asserted from D1  
bit (13) (XX1XX)b – PME# can be asserted from D2  
bit (14) (X1XXX)b – PME# can be asserted from D3hot  
bit (15) (1XXXX)b – PME# can be asserted from D3cold  
Read  
Only  
15:11  
See text  
If Power Management is not disabled in the EEPROM, the Ethernet  
controller supports PME# generation from D0 and D3hot states. If Power  
Management is not disabled and AUX_POWER = 1b, the Ethernet  
controller also supports the D3cold state.  
Condition  
00000b  
Value  
Power Management disabled in EEPROM  
AUX_POWER = 01001b Power Management enabled,  
AUX_POWER = 11001b Power Management enabled,  
D2_Support - If this bit is set to 1b, supports the D2 Power Management  
State.  
Read  
Only  
10  
0b  
The Ethernet controller returns a value of 0b for this bit indicating that it  
does not support D2 and cannot handle the PCI clock stopping in PCI  
66 MHz mode (or PCI-Xb mode) without RST# being asserted.  
D1_Support - If this bit is set to 1b, supports the D1 Power Management  
State. The Ethernet controller returns a value of 0b for this bit indicating  
that it does not support D1.  
Read  
Only  
09  
0b  
Read  
Only  
AUX Current – Specifies the auxiliary power current required for PME#  
generation from D3cold if the Data Register is not implemented.  
08:06  
000b  
DSI – The Device Specific Initialization bit indicates whether special  
initialization of this function is required (beyond the standard PCI  
configuration header) before the generic class device driver is able to use  
it. The Ethernet controller returns a value of 1b for this bit indicating that  
it’s device driver must be executed following transition to the D0  
uninitialized state.  
Read  
Only  
05  
1b  
0b  
Read  
Only  
04  
Reserved  
Loaded  
from  
EEPROM  
PME_Clock - When this bit is a 1b it indicates that the function relies on  
the presence of the PCI clock for PME# operation. The controller loads  
this bit from the EEPROM. Otherwise, it returns a 0b.  
Read  
Only  
03  
Read  
Only  
Version - A value of 010b indicates that this function complies with the  
Revision 1.1 of the PCI Power Management Interface Specification.  
02:00  
010b  
a.  
b.  
Not applicable to the 82541ER.  
Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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6.3.3.4  
Power Management Control / Status Register - (PMCSR)  
2 Bytes Offset = 4 (RO)  
Bits  
Default  
R/W  
Description  
PME_Status – This bit is set when the function would normally assert the  
PME# signal independent of the state of the PME_En bit. The Ethernet  
controller returns a value of 1b for this bit if a Wakeup condition has been  
detected.  
Read/  
Write 1b  
to clear  
0b (see  
description)  
15  
Writing a 1b clears this bit and deasserts PME#a.  
If the AUX_POWER input is 1b, the PME_Status field is only reset by  
LAN_PWR_GOOD. If AUX_POWER is 0b, PME_Status is also reset on the  
deassertion (rising edge) of RST#.  
00b  
Data_Scale - This 2- bit read-only field indicates the scaling factor to be  
used when interpreting the value of the Data register. This field outputs 01b  
(to indicate units of 0.1 watt) when Manageability is enabled in the  
EEPROM and the Data_Select field is set to 0, 3, 4, or 7, and 00b  
otherwise.  
01b if  
Manageability is  
enabled  
Read  
Only  
14:13  
12:09  
(see description)  
Data_Select - This 4-bit field is used to select which data is to be reported  
through the Data register and Data_Scale field. These bits are only writable  
when Power Management is enabled via EEPROM.  
Read/  
Write  
0000b  
PME_En – If Power Management is not disabled in the EEPROM, writing a  
1b to this register enables Wakeup and causes the Ethernet controller to  
assert PME# when it receives a Wakeup event enabled in the Wakeup Filter  
Control Register (WUFC).  
Note: This bit cannot be set for the 82541ER.  
0b on Power-On Read/  
If Power Management is disabled in the EEPROM, writing a 1b to this bit  
has no affect, and does not set the bit to 1b.  
08  
reset  
Write  
If the AUX_POWER input is 1b, the PME_En field is only reset by  
LAN_PWR_GOOD. If AUX_POWER is 0b, it is also reset on the  
deassertion (rising edge) of RST#.  
Note: If APM Wakeup is enabled, the PME# pin can be asserted even if  
PME_En is 0b. See Section 6.4.1 for details.  
Read  
Only  
07:02  
000000b  
Reserved - The Ethernet controller returns a value of 000000b for this field.  
PowerState - This 2-bit field is used both to determine the current power  
state of a function and to set the function into a new power state. The  
definition of the field values is as follows:  
00b - D0  
01b - D1 (ignored if written with this value)  
10b - D2 (ignored if written with this value)  
11b - D3  
Read/  
Write  
01:00  
00b  
If software attempts to write an unsupported state to this field, 00b or 10b, or  
if Power Management is disabled in the EEPROM, then the Ethernet  
controller completes the write operation normally on the bus, however the  
data is discarded and no state change occurs.  
These bits are cleared and the power state is returned to D0 after the trailing  
edge of RST#.  
a.  
Not applicable to the 82541ER.  
This register is used to control and monitor power management events in the Ethernet controller. If  
auxiliary power is present, as indicated by AUX_POWER = 1b, a PCI reset does not clear  
PME_En and PME_Status.  
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6.3.3.5  
6.3.3.6  
PMCSR_BSE Bridge Support Extensions  
1 Byte Offset = 6 (RO)  
This register indicates support for PCI bridge specific functions. Note that these functions are not  
implemented in the Ethernet controller and the values are set to 00h.  
Data Register  
1 Byte Offset = 7 (RO)  
Bits  
Default  
R/W  
Description  
00h (loaded  
from  
EEPROM)  
Data returned.  
Read  
Only  
07:00  
See the following explanation.  
This register is used to report power consumption and heat dissipation. Its value and meaning is  
determined by the value programmed in the Data_Select field of the Power Management Control/  
Status Register (PMCSR).  
Data Select  
Meaning  
0
1
2
3
4
5
6
7
8
D0 Power Consumed  
D1 Power Consumed  
D2 Power Consumed  
D3 Power Consumed  
D0 Power Dissipated  
D1 Power Dissipated  
D2 Power Dissipated  
D3 Power Dissipated  
Common power consumption of multi-function devices  
Reserved  
9-15  
The units are defined by the Data_Scale field of the Power Management Control/Status Register.  
Data Select  
Meaning  
0
1
Unknown (used for unsupported states)  
0.1 Watts (used by Ethernet controller for supported  
states)  
2
3
0.01 Watts  
0.001 Watts  
If power management is disabled in the EEPROM, then the data register always reads 0b.  
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If power management is not disabled and when the Data_Select field is programmed to 0 or 4, the  
Ethernet controller sets the Data Register to the D0 Power value in the EEPROM. When the  
Data_Select field is programmed to 3 or 7, the Ethernet controller sets the Data Register to the D3  
Power value in the EEPROM. Otherwise it returns 0b.  
6.4  
Wakeup  
The Ethernet controller supports two types of wakeup mechanisms:  
• Advanced Power Management (APM) Wakeup  
• ACPI Power Management Wakeup  
Note: The 82541ER contains power management logic, but is not spec-compliant, because it does not  
assert PME# for Magic Packets, Network Wakeup Packets, or link change status.  
The ACPI Power Management Wakeup uses the PME# pin to wake up the system. The Advanced  
Power Management Wakeup uses the PME# pin.  
6.4.1  
Advanced Power Management Wakeup  
“Advanced Power Management Wakeup”, or “APM Wakeup”, was previously known as “Wake on  
LAN”. The basic premise is to receive a broadcast or unicast packet with an explicit data pattern,  
and then to assert a signal to wake up the system. In the earlier generations of the Ethernet  
controller, this was accomplished by using special signal. The Ethernet controller would assert the  
signal for approximately 50 ms to signal a wakeup. The 82544GC/EI uses the APM_WAKEUP  
pin for this function. For the remaining Ethernet controllers, the PCI PME# signal has been used to  
wake up the system.  
On power-up, the Ethernet controller reads the APM Enable bits from the EEPROM Initialization  
Control Word 2 into the APM Enable (APME) bits of the Wakeup Control Register (WUC). These  
bits control enabling of APM Wakeup.  
When APM Wakeup is enabled, the Ethernet controller checks all incoming packets for “Magic  
Packets”. See Section 6.4.3.1.4 for a definition of “Magic Packets*”.  
Once the Ethernet controller receives a matching magic packet, it:  
• Sets the PME_Status bit in the Power Management Control / Status Register (PMCSR) and  
asserts PME#. If the Assert PME On APM Wakeup (APMPME) bit is set in the Wakeup  
Control Register (WUCR).  
• Stores the first 128 bytes of the packet in the Wakeup Packet Memory (WUPM).  
• Sets the Magic Packet Received bit in the Wakeup Status Register (WUS).  
• Sets the packet length in the Wakeup Packet Length Register (WUPL).  
• Asserts PME# until the driver clears the Magic Packet Received AMAG bit in the Wakeup  
Status Register (WUS), the driver clears the Assert PME On APM Wakeup (APMPME) bit in  
the Wakeup Control Register (WUC), or the driver disables APM Wakeup.  
• For the 82544GC/EI only, asserts APM_WAKEUP for 50 ms. For purposes of  
APM_WAKEUP assertion, the 82544GC/EI ignores any additional magic packets received  
during that 50 ms. If the 82544GC/EI receives another magic packet afterwards, it reasserts  
APM_WAKEUP for another 50 ms.  
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• Maintains the first magic packet received in the Wakeup Packet Memory (WPM) until the  
driver writes a 0b to the Magic Packet Received MAG bit in the Wakeup Status Register  
(WUS).  
“APM Wakeup” is supported in all power states and only disabled if a subsequent EEPROM read  
results in the APM Wakeup bit being cleared or software explicitly writes a 0b to the APM Wakeup  
(APM) bit of the WUC register.  
6.4.2  
ACPI Power Management Wakeup  
The Ethernet controller supports ACPI Power Management based wakeups. It generates system  
wakeup events from three sources:  
• Reception of a “Magic Packet”.  
• Reception of a Network Wakeup Packet.  
• Detection of a link change of state.  
Note: The 82541ER does not support ACPI wakeup events.  
Activating ACPI Power Management Wakeup requires:  
• The software driver to program the Wakeup Filter Control Register (WUFC). This indicates  
the packets the driver wishes to wake up and supplies the necessary data to the IP Address  
Table (IPAT) and the Flexible Filter Mask Table (FFMT), Flexible Filter Length Table (FFLT),  
and the Flexible Filter Value Table (FFVT). The driver can also set the Link Status Change  
Wakeup Enable (LNKC) bit in the Wakeup Filter Control Register (WUFC) to cause wakeup  
when the link changes state.  
• The OS to write a 1b to the Pme_En bit of the Power Management Control / Status Register  
(PMCSR).  
Normally, after enabling wakeup, the OS sets the Ethernet controller to D3 (low-power mode).  
Once wakeup is enabled, the Ethernet controller monitors incoming packets, first filtering them  
according to its standard address filtering method, then filtering them with all of the enabled  
wakeup filters. If a packet passes both the standard address filtering and at least one of the enabled  
wakeup filters, the Ethernet controller:  
• Sets the PME_Status bit in the Power Management Control / Status Register (PMCSR)  
• Assert PME#. If the PME_En bit in the Power Management Control / Status Register  
(PMCSR) is set.  
• Stores the first 128 bytes of the packet in the Wakeup Packet Memory.  
• Sets one or more of the “Received” bits in the Wakeup Status Register (WUS). Note that the  
Ethernet controller sets more than one bit if a packet matches more than one filter.  
• Sets the packet length in the Wakeup Packet Length Register (WUPL).  
If enabled, a link state change wakeup causes similar results. For example, setting PME_Status,  
asserting PME#, and setting the Link Status Changed (LNKC) bit in the Wakeup Status Register  
(WUSR) when the link goes up or down.  
PME# remains asserted until the OS either writes a 1b to the PME_Status bit of the PMCSR  
register or writes a 0b to the Pme_En bit.  
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After receiving a wakeup packet, the Ethernet controller ignores any subsequent wakeup packets  
until the driver clears all of the “Received” bits in the Wakeup Status Register (WUS). It also  
ignores link change events until the driver clears the Link Status Changed (LNKC) bit in the  
Wakeup Status Register (WUSR).  
6.4.3  
Wakeup Packets  
The Ethernet controller supports various wakeup packets using two types of filters:  
• Pre-defined Filters  
• Flexible Filters  
Each of these filters are enabled if the corresponding bit in the Wakeup Filter Control Register  
(WUFC) is set to 1b.  
6.4.3.1  
Pre-Defined Filters  
The following packets are supported by the Ethernet controller’s pre-defined filters:  
• Directed Packet (including exact, multicast indexed, and broadcast)  
• Magic Packet* (not applicable to the 82541ER)  
• ARP/IPv4 Request Packet (ARP Request Packet for the 82544GC/EI)  
• Directed IPv4 Packet (Directed IP Packet for the 82544GC/EI)  
1
• Directed IPv6 Packet  
Each of these filters are enabled if the corresponding bit in the Wakeup Filter Control Register  
(WUFC) is set to 1b.  
The following explanation of each filter includes a table listing which bytes at which offsets are  
2
compared to determine if the packet passes the filter. Note that both VLAN frames and LLC/Snap  
can increase the given offsets if they are present (see Section 9.3 for details).  
For the 82541PI/GI/EI and 82547GI/EI, various tables can also include a reference to a possible  
VLAN Tag and LLC/SNAP Header. These Ethernet controllers detect VLAN and LLC/Snap  
frames by checking the initial size/type field. They first check for a VLAN header by comparing  
the size/type field to the value programmed in the VLAN EtherType register. If the field matches,  
the Ethernet controllers consider the frame a VLAN frame. They then check the VLAN ID against  
the values programmed in the VLAN Filter Table Array. If the ID matches the packet, processing  
continues. If the ID doesn’t match, or the CTRL.VME bit is 0b, and the VLAN Tag is listed as  
compare in the table, the packet is not considered a wakeup packet.  
After processing a possible VLAN Tag, the 82541PI/GI/EI and 82547GI/EI Ethernet controllers  
check for an LLC/SNAP Header. If the size/type field is less than or equal to 1500 bytes, they  
check the following 6 bytes for the pattern of AAAA03000000h. If the pattern matches, then the  
packet processing continues. If the pattern doesn’t match, and the LLC/SNAP Header is listed as  
compare or check in the table, the packet is not considered a wakeup packet.  
6.4.3.1.1  
Directed Exact Packet  
1. Not applicable to the 82544GC/EI.  
2. Not applicable to the 82541ER.  
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Power Management  
The Ethernet controller generates a wakeup event after receiving any packet whose destination  
address matches one of the 16 valid programmed Receive Addresses if the Directed Exact Wakeup  
Enable bit is set in the Wakeup Filter Control Register (WUFC.EX).  
# of  
bytes  
Offset  
Field  
Value  
Action  
Comment  
Match any pre-  
programmed address  
0
6
Destination Address  
Compare  
6.4.3.1.2  
Directed Multicast Packet  
For multicast packets, the upper bits of the incoming packet’s destination address indexes a bit  
vector (Multicast Table Array) that indicates whether to accept the packet. If the Directed Multicast  
Wakeup Enable bit set in the Wakeup Filter Control Register (WUFC.MC) and the indexed bit in  
the vector is one then the Ethernet controller generates a wakeup event. The exact bits used in the  
comparison are programmed by software in the Multicast Offset field of the Receive Control  
Register (RCTL.MO).  
# of  
Bytes  
Offset  
Field  
Value  
Action  
Comment  
0
6
Destination Address  
Compare  
See Section 6.4.3.1.2.  
6.4.3.1.3  
Broadcast  
If the Broadcast Wakeup Enable bit in the Wakeup Filter Control Register (WUFC.BC) is set, the  
Ethernet controller generates a wakeup event when it receives a broadcast packet.  
# of  
bytes  
Offset  
Field  
Value  
Action  
Comment  
0
6
Destination Address  
FF*6  
Compare  
1
6.4.3.1.4  
Magic Packet*  
Magic Packet* technology is defined at: http://www.amd.com/products/npd/overview/20212.html.  
The Ethernet controller expects the destination address to:  
1. Be the broadcast address (FF.FF.FF.FF.FF.FF)  
2. Match the value in Receive Address Register 0 (RAH0, RAL0). This is initially loaded from  
the EEPROM but can be changed by the software driver.  
3. Match any other address filtering enabled by the software driver.  
The Ethernet controller searches for the contents of Receive Address Register 0 (RAH0, RAL0) as  
the embedded IEEE address. It considers any non FF byte after a series of at least 6 FFs to be the  
start of the address for comparison purposes (for example, it catches the case of 7 FFs followed by  
the address). As soon as one of the first 96 bytes after a string of FFs doesn’t match, it continues to  
search for anther set of at least 6 FFs followed by the 16 copies of the IEEE address later in the  
packet. Note that this definition precludes the first byte of the destination address from being FF.  
1. Not applicable to the 82541ER.  
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# of  
bytes  
Offset  
Field  
Value  
Action  
Compare  
Comment  
0
6
6
6
Destination Address  
Source Address  
MAC Header –  
processed by main  
address filter  
Skip  
12a  
12a  
12a  
any  
8
4
4
6
Possible LLC/SNAP Header  
Possible VLAN Tag  
Type  
Skip  
Skip  
Skip  
Synchronizing Stream  
FF*6+  
A*16  
Compare  
Compared to Receive  
Address Register 0  
(RAH0, RAL0)  
any+6  
96  
16 copies of Node Address  
Compare  
a.  
Not applicable to the 82541PI/GI/EI and 82547GI/EI.  
A Magic Packet’s destination address must match the address filtering enabled in the configuration  
registers with the exception that broadcast packets are considered to match even if the Broadcast  
Accept bit of the Receive Control Register (RCTL.BAM) is 0b. If APM Wakeup is enabled in the  
EEPROM, Ethernet controller starts up with the Receive Address Register 0 (RAH0, RAL0)  
loaded from the EEPROM. This is enables it to accept packets with the matching IEEE address  
before the driver comes up.  
Note: Accepting broadcast magic packets for wakeup purposes when the Broadcast Accept bit of the  
Receive Control Register (RCTL.BAM) is 0b is a change from the 82544GC/EI Ethernet  
controller, which initialized RCTL.BAM to 1b if APM was enabled in the EEPROM, but then  
required that bit to be 1b to accept broadcast Magic Packets, unless broadcast packets passed  
another perfect or multicast filter.  
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6.4.3.1.5  
ARP/IPv4 Request Packet1  
The Ethernet controller supports receiving ARP Request packets for wakeup if the ARP bit is set in  
the Wakeup Filter Control Register (WUFC). Four IPv4 addresses are supported which are  
2
programmed in the IPv4 Address Table (IPv4AT) . A successfully matched packet must contain a  
broadcast MAC address, a Protocol Type of 0806h, an ARP OPCODE of 01h, and one of the four  
programmed IPv4 addresses. The Ethernet controller also handles ARP Request packets that have  
VLAN tagging on both Ethernet II and Ethernet SNAP types.  
# of  
bytes  
Offset  
Field  
Value  
Action  
Compare  
Comment  
0
6
6
Destination Address  
Source Address  
6
8
Skip  
MAC Header –  
processed by main  
address filter  
Skip  
Checka  
12  
Type<= 1500 and  
Possible LLC/SNAP Header  
Possible VLAN Tag  
Type  
12 + Sa  
AAAA_0300_0000ha  
D = (0/8)a  
4
Skip  
Checka  
12  
8100h and check IDa  
S = (0/4)a  
12  
2
2
2
1
1
2
0806h  
0001h  
0800h  
06h  
Compare  
Compare  
Compare  
Compare  
Compare  
Compare  
ARP  
12 + D + Sa  
14  
HW Type  
14 + D + Sa  
16  
Protocol Type  
16 + D + Sa  
18  
Hardware Size  
Protocol Address Length  
Operation  
18 + D + Sa  
19  
04h  
19 + D + Sa  
20  
0001h  
20 + D + Sa  
22  
6
4
Sender HW Address  
Sender IP Address  
-
-
Ignore  
Ignore  
22 + D + Sa  
28  
28 + D + Sa  
32  
6
4
Target HW Address  
Target IP Address  
-
Ignore  
32 + D + Sa  
38  
May match any of 4  
values in IPv4ATb  
IPv4ATb  
Compare  
38 + D + Sa  
a.  
b.  
82541PI/GI/EI and 82547GI/EI only.  
IPAT for the 82544GC/EI.  
1. ARP Request Packet for the 82544GC/EI.  
2. Four IP addresses are supported which are programmed in the IP Address Table (IPAT) for the 82544GC/EI.  
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6.4.3.1.6  
Directed IPv4 Packet1  
2
The Ethernet controller supports receiving Directed IPv4 packets for wakeup if the IPv4 bit is set  
in the WakeUp Filter Control Register (WUFC). Four IPv4 addresses are supported which are  
programmed in the IPv4 Address Table (IPv4AT). A successfully matched packet must contain the  
station’s MAC address, a Protocol Type of 0800h, and one of the four programmed IPv4 addresses.  
The Ethernet controller also handles Directed IPv4 packets that have VLAN tagging on both  
Ethernet II and Ethernet SNAP types.  
Offset  
# of bytes  
Field  
Value  
Action  
Compare  
Comment  
0
6
6
6
Destination Address  
Skip  
Ignorea  
Source Address  
MAC Header –  
processed by main  
address filter  
Type<= 1500  
and  
8
Skip  
Checka  
12  
Possible LLC/SNAP Header  
12 + Sa  
AAAA_0300_  
D = (0/8)a  
0000ha  
4
Skip  
Checka  
8100h and  
check IDa  
12  
Possible VLAN Tag  
Type  
S = (0/4)a  
12  
2
1
1
2
2
2
1
1
2
4
4
0800h  
Compare  
Compare  
Ignore  
IP  
12 + D + Sa  
14  
Check IPv4b and  
header length  
Version/HDR length  
Type of Service  
Packet Length  
Identification  
4Xh  
14 + D + Sa  
15  
-
15 + D + Sa  
16  
-
Ignore  
16 + D + Sa  
18  
-
Ignore  
18 + D + Sa  
20  
Fragment Info  
Time to live  
-
Ignore  
20 + D + Sa  
22  
-
Ignore  
22 + D + Sa  
23  
Protocol  
-
Ignore  
23 + D + Sa  
24  
Header Checksum  
Source IP Address  
Destination IP Address  
-
Ignore  
24 + D + Sa  
26  
-
Ignore  
26 + D + Sa  
30  
May match any of four  
values in IPv4ATb  
IPv4ATb  
Compare  
30 + D + Sa  
a.  
b.  
82541PI/GI/EI and 82547GI/EI only.  
IP instead of IPv4 for the 82544GC/EI.  
1. Directed IP Packet for the 82544GC/EI.  
2. IP instead of IPv4 for the 82544GC/EI.  
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6.4.3.2  
Directed IPv6 Packet1  
The Ethernet controller supports receiving Directed IPv6 packets for wakeup if the IPv6 bit is set in  
the Wakeup Filter Control Register (WUFC). One IPv6 address is supported and it is programmed  
in the IPv6 Address Table (IPv6AT). A successfully matched packet must contain the station’s  
MAC address, a Protocol Type of 0800h, and the programmed IPv6 address. The Ethernet  
controller also handles Directed IPv6 packets that have VLAN tagging on both Ethernet II and  
Ethernet SNAP types.  
.
Offset  
# of bytes  
Field  
Value  
Action  
Compare  
Comment  
0
6
6
6
Destination Address  
Skip  
Ignorea  
Source Address  
MAC Header –  
processed by main  
address filter  
Type<=  
8
Skip  
Checka  
12  
1500 and  
AAAA_030  
0_0000ha  
Possible LLC/SNAP Header  
12 + Sa  
D = (0/8)a  
4
Skip  
Checka  
8100h and  
check IDa  
12  
Possible VLAN Tag  
Type  
S = (0/4)a  
0800h  
86DDa  
IP  
IPv6a  
12  
2
1
Compare  
Compare  
12 + D + Sa  
Version/ Priority  
Version/Traffic Classa  
14  
6Xh  
-
Check IPv6  
14 + D + Sa  
15  
3
2
Traffic Classa/Flow Label  
Payload Length  
Ignore  
Ignore  
15 + D + Sa  
18  
-
-
18 + D + Sa  
20  
IPv6 Next  
Header  
Typesa  
1
Next Header  
Ignore  
20 + D + Sa  
21  
1
Hop Limit  
-
Ignore  
21 + D + Sa  
22  
16  
16  
Source IP Address  
Destination IP Address  
-
Ignore  
22 + D + Sa  
38  
IPv6AT  
Compare  
Match value in IPv6AT  
38 + D + Sa  
a.  
82541PI/GI/EI and 82547GI/EI only.  
1. Not applicable to the 82544GC/EI.  
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6.4.3.3  
Flexible Filter  
The Ethernet controller supports a total of four flexible filters. Each filter is configured to  
recognize any arbitrary pattern within the first 128 bytes of the packet. To configure the flexible  
filter, the software driver must mask values into the Flexible Filter Mask Table (FFMT), the  
required values into the Flexible Filter Value Table (FFVT), and the minimum packet length into  
the Flexible Filter Length Table (FFLT). These contain separate values for each filter. The software  
driver must also enable the filter in the Wakeup Filter Control Register (WUFC) as well as the  
overall wakeup functionality by setting PME_En in the Power Management Control Status  
Register or the Wakeup Control Register.  
Once enabled, the flexible filters scan incoming packets for a match. If the filter encounters any  
byte in the packet where the mask bit is 1b and the byte doesn’t match the byte programmed in the  
Flexible Filter Value Table (FFVT), then the filter failed that packet. If the filter reaches the  
required length without failing the packet, it passes the packet and generates a wakeup event. It  
ignores any mask bits set to 1b beyond the required length. (the wakeup packet is stored, see  
Section 6.4.3.5).  
For the 82541xx and 82547GI/EI, the flexible filter does not have any way to automatically skip  
VLAN or LLC/SNAP headers. If such headers are included, the offsets of the subsequent fields  
must be adjusted accordingly.  
Note: This following flexible packet filters are listed for reference only.  
6.4.3.3.1  
IPX Diagnostic Responder Request Packet Example1  
Offset  
# of bytes  
Field  
Destination Address  
Source Address  
Value  
Action  
Compare  
Skip  
Comment  
0
6
6
6
MAC Header –  
processed by  
main address filter  
Compare or  
Skip  
12  
S = (0/4)  
Possible VLAN Tag  
Compare or  
Skip  
12 + S  
D = (0/8)  
2
Possible LLC/SNAP Header  
12 + D + S  
Type  
8137h  
Compare  
Ignore  
IPX  
14 + D + S 16  
30 + D + S  
Some IPX Stuff  
IPX Diagnostic Socket  
-
2
0456h  
Compare  
1. 82541xx and 82547GI/EI only.  
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6.4.3.3.2  
Directed IPX Packet Example  
A valid Directed IPX Packet contains the station’s MAC address, a Protocol Type of 8137h, and an  
IPX Node Address that equals to the station’s MAC address. It can include LLC/SNAP Headers  
and VLAN Tags. Since filtering this packet relies on the flexible filters, which use offsets specified  
by the OS directly, the OS must account for the extra offset LLC/SNAP Headers and VLAN tags.  
# of  
bytes  
Offset  
Field  
Value  
Action  
Comment  
0
6
6
6
Destination Address  
Source Address  
Compare  
MAC Header –  
processed by main  
address filter  
Skip  
Skip  
8
12  
Possible LLC/SNAP Header  
Possible VLAN Tag  
12 + Sa  
12  
Compare or  
Skipa  
D = (0/8)a  
Skip  
4
Compare or  
Skipa  
S = (0/4)a  
12  
2
Type  
8137h  
Compare  
Ignore  
IPX  
12 + D + Sa  
14  
10  
6
Some IPX Stuff  
IPX Node Address  
-
14 + D + Sa  
24  
Receive  
Address 0  
Must match Receive  
Address 0  
Compare  
24 + D + Sa  
a.  
82541PI/GI/EI and 82547GI/EI.  
6.4.3.4  
IPv6 Neighbor Discovery Filter1  
In IPv6, a Neighbor Discovery packet is used for address resolution. A flexible filter can be used to  
check for a “Neighborhood Discovery Packet”.  
82541xx and 82547GI/EI Only  
# of  
Bytes  
Offset  
Field  
Value  
Action  
Comment  
0
6
6
Destination Address  
Source Address  
Compare  
Skip  
6
4
MAC Header –  
processed by main  
address filter, or  
broadcast  
Compare or  
Skip  
12  
12  
Possible VLAN Tag  
Compare or  
Skip  
8
Possible LLC/SNAP Header  
12+D+S  
14+D+S  
15+D+S  
2
1
3
Type  
86DDh  
Compare  
Compare  
Ignore  
IP  
Version/ Traffic Class  
Traffic Class/Flow Label  
6Xh  
-
Check IPv6  
1. Not applicable to the 82544GC/EI.  
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# of  
Bytes  
Offset  
18+D+S  
Field  
Payload Length  
Value  
Action  
Ignore  
Comment  
2
-
ICMP, or IPv6 next  
headers:  
+ routing (2Bh)  
+ dest options (3Ch)  
+ hop-by-hop (00h)  
3Ah, 00h,  
2Bh, or  
3Ch  
20+D+S  
1
Next Header  
Check  
21+D+S  
22+D+S  
38+D+S  
1
Hop Limit  
FFh  
-
Check  
Ignore  
Ignore  
16  
16  
Source IP Address  
Destination IP Address  
Process headers to  
get next header.  
Header type must be  
routing, destination  
options, or hop-by-  
hop.  
54+D+S  
N
Possible IPv6 Next Headers  
-
Check  
54+D+S+N  
55+D+S+N  
56+D+S+N  
58+D+S+N  
62+D+S+N  
1
Type  
87h  
Check  
Check  
Ignore  
Ignore  
Check  
Neighbor Solicitation  
1
Code  
00h  
2
ICMP Header Checksum  
Reserved  
-
-
-
4
16  
Target Address  
Match IPV6AT[0]  
Possible source link-layer  
address  
78+D+S+N  
N
-
Ignore  
...  
any  
4
-
-
-
Ignore  
Packet data  
last 4  
CRC  
Compare  
Validate correct  
6.4.3.5  
Wakeup Packet Storage  
The Ethernet controller saves the first 128 bytes of the wakeup packet in its internal buffer, which  
can be read through the Wakeup Packet Memory (WUPM) after system wakeup.  
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Ethernet Interface  
8
8.1  
Introduction  
The PCI/PCI-X Family of Gigabit Ethernet Controllers provide a complete CSMA/CD function  
supporting IEEE 802.3 (10Mb/s), 802.3u (100Mb/s), 802.3z and 802.3ab (1000Mb/s)  
implementations. They perform all of the functions required for transmission, reception and  
collision handling called out in the standards.  
The internal Gigabit Media Independent Interface/Media Independent Interface (GMII/MII)  
supports the onboard 10/100/1000 BASE-T transceivers full duplex operation and supports the  
onboard 10/100 BASE-T transceivers in full or half duplex operation.  
Note: The 82541xx, 82547GI/EI, and 82540EP/EM do support SerDes functionality.  
8.2  
Link Interfaces Overview  
82546GB/EB and 82545GM/EM Ethernet controllers contain an internal 10-bit Fibre Channel  
Interface (TBI), as specified in IEEE 802.3z, for full-duplex operation with a SerDes transceiver.  
This configuration is applicable to 1000BASE-SX, -LX, or –CX links. When in internal SerDes  
mode, they provide the full Physical Coding Sub-layer implementation including Auto-Negotiation  
as called out in IEEE 802.3z.  
82544GC/EI Ethernet controllers support a 10-bit TBI, as specified in IEEE 802.3z, for full-  
duplex operation with a SerDes transceiver. This configuration is applicable to 1000BASE-SX, -  
LX, or –CX links. When in TBI mode, they provide the full Physical Coding Sub-layer  
implementation including Auto-Negotiation as called out in IEEE 802.3z.  
Selection between the various configurations is programmable via each MAC’s Extended Device  
Control Register (CTRL_EXT.LINK_MODE bits) and defaulted via EEPROM settings. Note that  
the external TBI interface is a single resource that can only be associated with a single MAC.  
The GMII/MII mode used to communicate between the MAC and the internal PHY supports 10/  
100/1000 Mbps operation, with both half- and full-duplex operation at 10/100 Mbps, and full-  
duplex operation at 1000 Mbps.  
Note: The Ethernet controllers are optimized for full-duplex operation in 1000 Mbps mode. Half-duplex  
1000 Mbps operation is NOT supported and is not recommended.  
The internal copper PHY features 10/100/1000-BaseT signalling and is capable of performing  
intelligent power-management based on both the system power-state and LAN energy-detection  
(detection of unplugged cables). Power management includes ability to shut-down to extremely  
low (powered-down) state when not needed, as well as ability to auto-negotiate to lower-speed  
(and less power-hungry) 10/100 Mbps operation when the system is in low power-states.  
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8.2.1  
Internal SerDes Interface/TBI Mode– 1Gb/s1  
The 82546GB/EB and 82545GM/EM Ethernet controllers contain one or two internal SerDes  
devices (depending whether or not they support one or two ports). The MAC communicates with  
the SerDes over a TBI interface. Normally, this interface is not exposed externally.  
For the 82554GC/EI, TBI mode is selectable via an external pin TBI-MODE. Software cannot  
override this pin. This interface has 125 Mb/s 10-bit data paths for both receive and transmit. The  
clock at the transmit interface operates at 125 MHz; the receive interface has two clocks running at  
62.5 MHz that are 180 degrees out of phase as follows:  
• RX_DATA: 10-bit receive data bus  
• TX_DATA: 10-bit transmit data bus  
• RBC0/I_RBC1: Receive clocks (62.5 MHz; 180 degree phase shift between I_RBC0 and  
I_RBCI)  
• GTX_CLK: Transmit clock (125 MHz)  
2
8.2.1.1  
8.2.1.2  
Gigabit Physical Coding Sub-Layer (PCS) for the Internal SerDes  
The Ethernet controller integrates the 802.3z PCS function on-chip. The on-chip PCS circuitry is  
used when the link interface is configured for internal SerDes mode and is bypassed in internal  
PHY mode.  
The packet encapsulation is based on the Fibre Channel physical layer (FC0/FC1) and uses the  
same coding scheme to maintain transition density and DC balance. The physical layer device is a  
SerDes and is used for 1000BASE-SX, -LX, or -CX configurations.  
8B10B Encoding/Decoding  
The Gigabit PCS circuitry uses the same transmission coding scheme used in the Fibre Channel  
physical layer specification. The 8B10B coding scheme was chosen by the IEEE standards  
committee in order to provide a balanced, continuous stream with sufficient transition density to  
allow for clock recovery at the receiving station. There is a 25 percent overhead for this  
transmission code which accounts for the data signaling rate of 1250 Mb/s with 1000 Mb/s of  
actual data.  
1. TBI (10-Bit Interface) - 1GB/s for the 82554GC/EI.  
2. Gigabit Physical Coding Sub-Layer (PCS) for TBI (82554GC/EI).  
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8.2.1.3  
Code Groups and Ordered Sets  
Code group and ordered set definitions are defined in clause 36 of the IEEE 802.3z standard. These  
represent special symbols used in the encapsulation of Gigabit Ethernet packets. Table 8-1 lists a  
brief description of defined ordered sets for informational purposes only.  
Table 8-1. Code Group and Ordered Set Usage  
# of Code  
Groups  
Code  
Ordered_Set  
Usage  
General reference to configuration ordered sets, either  
/C1/ or /C2/, which is used during Auto Negotiation to  
advertise & negotiate link operation information between  
link partners. Last two code groups contain config base  
and next page registers.  
/C/  
Configuration  
4
See /C/. Differs from /C2/ in second code group for  
maintaining proper signaling disparity.  
/C1/  
/C2/  
Configuration 1  
Configuration 2  
4
4
See /C/. Differs from /C1/ in second code group for  
maintaining proper signaling disparity.  
General reference to IDLE ordered sets. IDLE characters  
are continually transmitted by the end stations and are  
replaced by encapsulated packet data. The transitions in  
the IDLE stream allow the SerDes to maintain clock and  
symbol synchronization between to link partners.  
/I/  
IDLE  
2
See /I/. Differs from /I2/ in second code group for  
maintaining proper signaling disparity.  
/I1/  
/I2/  
IDLE 1  
IDLE 2  
2
2
See /I/. Differs from /I1/ in second code group for  
maintaining proper signaling disparity.  
This ordered set is used to indicate carrier extension to  
the receiving PCS. It is also used as part of the  
end_of_packet encapsulation delimiter as well as IPG for  
packets in a burst of packets.  
/R/  
/S/  
Carrier_Extend  
Start_of_Packet  
1
1
The SPD (start_of_packet delimiter) ordered set is used to  
indicate the starting boundary of a packet transmission.  
This symbol replaces the last byte of the preamble  
received from the MAC layer.  
The EPD (end_of_packet delimiter) is comprised of three  
ordered sets. The /T/ symbol is always the first of these  
and indicates the ending boundary of a packet.  
/T/  
/V/  
End_of_Packet  
1
1
The /V/ ordered set is used by the PCS to indicate error  
propagation between stations. This is normally intended to  
be used by repeaters to indicate collisions.  
Error_Propagation  
8.2.2  
GMII – 1 Gb/s  
The internal Gigabit Media Independent Interface (GMII) is similar to the 10/100 Mb/s Media  
Independent Interface (MII). The GMII uses the MII management interface and registers. These  
common elements of operation allow the Ethernet controller to determine PHY capabilities for any  
supported speed of operation and configuration of the hardware based on those capabilities.  
Most of the MII and GMII signals use the same names, but the width of the RX and TX data busses  
and the semantics of the associated control signals differ between MII and GMII operation. The  
GMII transmit path clocking also differs significantly from MII clocking.  
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8.2.3  
MII – 10/100 Mb/s  
The internal MII implementation for the Ethernet controller provides full IEEE 802.3 and IEEE  
802.3u compliant operation for 10Mb/s and 100Mb/s operation in conjunction with the onboard  
MII compliant PHY.  
The MII uses a clocked, nibble-wide (4-bit) data path in each direction. The clock rate for Fast  
Ethernet operation is 25 MHz with data transfer speed of 4 bits x 25 MHz = 100 Mb/s. For  
10 Mb/s operation the clock rate is 2.5 MHz and also uses the nibble-wide data path.  
1
8.3  
Internal Interface  
The Ethernet controller supports the IEEE 802.3 MII Management Interface also known as the  
Management Data Input/Output (MDI/O) Interface. This interface allows upper-layer devices to  
monitor and control the state of the PHY.  
For the 82546GB/EB, 82545GM/EM, 82541xx, 82540EP/EM, and 82547GI/EI, the MDI/O  
interface consists of an internal connection, a special protocol that runs across the connection, and  
an internal set of addressable registers. For the 82541xx and 82547GI/EI, the physical interface  
between the MAC and PHY is not available externally.  
For the 82544GC/EI, the MDI/O interface consists of a physical connection, a special protocol that  
runs across the connection, and an internal set of addressable registers. The physical interface  
consists of a (B_MDIO) data line and a clock line (O_MDC).  
• O_MDC:  
Management Data Clock, used by the PHY as a clock timing reference for information transfer  
on the B_MDI/O signal. The O_MDC is not a continuous signal and can be frozen by the  
Ethernet controller when no management data is transferred. The O_MDC signal has a  
maximum operating frequency of 2.5 MHz.  
• B_MDO:  
Management Data I/O, a bidirectional data signal used to transfer control information and  
status between the Ethernet controller and the PHY (read and write PHY management  
registers). The B_MDO signal is sampled by the rising edge of the O_MDC signal.  
Software can use MDI/O to read and write registers in a internal PHY by accessing the Ethernet  
controller’s MDIC register.  
8.4  
Duplex Operation  
The 82546GB/EB and 82545GM/EM supports half-duplex and full-duplex 10/100 Mb/s mode.  
Half-duplex in 1000 Mb/s mode using either the Internal SerDes or GMII interface is NOT  
supported.  
The 82544GC/EI, 82540EP/EM, 82541xx, and 82547GI/EI, support half-duplex and full-duplex  
10/100 Mb/s mode or 1000 MB/s mode. However, only full-duplex mode is supported when the  
82544GC/EI TBI interface option is used.  
1. MDIO/MDC Interface for the 82544GC/EI, 82540EP/EM, 82541xx, and 82547GI/EI.  
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Configuration of the duplex operation of the Ethernet controller can be forced or determined via  
the Auto-Negotiation process. See Section 8.6 for details on link configuration setup and  
resolution.  
8.4.1  
Full Duplex  
All aspects of the IEEE 802.3, 802.3u, 802.3z, and 802.3ab specifications are supported in full  
duplex operation. Full duplex operation is enabled by several mechanisms depending on the speed  
configuration of the Ethernet controller and the specific capabilities of the PHY used in the  
application. During full duplex operation, the Ethernet controller may transmit and receive packets  
simultaneously across the link interface.  
In Internal Serdes mode for the 82546GB/EB and 82545GM/EM (TBI mode for the 82544GC/  
EI), the transmission and reception of packets is indicated by symbols embedded in the data  
stream. These symbols delineate the packet encapsulation and the protocol does not rely on other  
control signals. See Section 8.2.1.3 for details.  
8.4.2  
Half Duplex  
Note: The Ethernet controller operates in half duplex mode only when configured for internal PHY  
mode. For the 82546GB/EB and 82545GM/EM, internal SerDes mode does not support half  
duplex operation.  
In half duplex mode, the Ethernet controller attempts to avoid contention with other traffic on the  
wire, by monitoring the carrier sense signal provided by the internal PHY, and deferring to passing  
traffic. When the Internal Carrier Sense signal is deasserted or after sufficient InterPacket Gap  
(IPG) has elapsed after a transmission, frame transmission can begin.  
In the case of a collision, the internal PHY asserts a collision signal. Transmission of the frame  
stops within four clock times and then the Ethernet controller sends a JAM sequence onto the link.  
After the end of a collided transmission, the Ethernet controller backs off and attempts to  
retransmit per the standard CSMA/CD method. Note that the retransmission is done from the data  
stored internally in the Ethernet controller transmit packet buffer. The Ethernet controller does not  
access data in host memory again.  
In the case of a successful transmission, the Ethernet controller is ready to transmit any other  
frames queued in its transmit FIFO within the minimum Inter Frame Spacing (IFS) of the link.  
The internal carrier sense signal is expected to be asserted before one slot time has elapsed;  
however, the transmission completes successfully even if internal carrier sense is not asserted. If  
internal carrier sense is not asserted within the slot time window, the PHY is not behaving properly  
and can either be configured incorrectly or be in a link down situation. Note that this event is  
counted in the Transmit Without CRS statistic register (see Section 13.7.12).  
Half duplex reception is as indicated for full duplex in Section 8.4.1 except for 1000 Mb/s specific  
operation, as described in Section 8.4.2.1 and Section 8.4.2.2.  
The Ethernet controller does not provide support for half-duplex operation as specified in the IEEE  
802.3z specification when operating at 1000 Mb/s in internal PHY mode.  
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For receives, the Ethernet controller supports carrier extended packets and packets generated  
during packet bursting operations (see Section 8.4.2.1 and Section 8.4.2.2). The Ethernet controller  
can be configured to transmit in packet burst mode via the TCTL.PBE bit in the Transmit Control  
register (see Section 13.4.46).  
Carrier extension is only defined in the IEEE 802.3z standard for half-duplex operation for  
operation frequencies above 100 Mb/s (Gigabit Ethernet).  
8.4.2.1  
Carrier Extension (1000 Mb/s Only)  
One of the objectives of the IEEE 802.3z standard development was to support a maximum  
collision domain of 200 m and retain the IEEE 802.3 Ethernet frame format. The scaling of the line  
transfer rate by 10x to 1 Gb/s reduced the bit time by 10 and effectively reduced the theoretical  
collision domain to an unusable size with the minimum packet size of 64 bytes. To overcome this,  
the 802.3z specification development added the notion of carrier extension to the standard.  
Carrier extension provides a method to increase the duration of the carrier event to a minimum  
usable duration in order to meet the collision domain objective. Packets that are signaled from the  
CSMA/CD layer that do not meet the minimum slot time of 512 bytes have extension bytes  
appended to them in order to meet this minimum slot time requirement. The extension bytes are  
defined within the context of the frame encapsulation discussion of the 802.3z standard and are  
recognized by 802.3z compliant devices (see Figure 8-1).  
Preamble  
SFD  
DA  
SA  
T/L  
Data/Pad  
FCS  
Extension  
Minimum Frame Size  
Slot Time  
f Carrier Eve  
Duration o  
nt  
Figure 8-1. Carrier Extended Frame Format  
The Ethernet controller supports the reception and transmission of carrier extended packets. Carrier  
extension is implemented via specifying the collision distance parameter, COLD, in the Transmit  
Control register (TCTL). Note that this field is evaluated whether in full- or half- duplex operation.  
8.4.2.2  
Packet Bursting  
In an attempt to recover some of the lost overhead encountered with short duration packets using  
carrier extension, the IEEE 802.3z standard incorporates the implementation of packet bursting.  
Packet bursting is a mechanism that allows a transmitting device to “own-the-wire” for a longer  
duration and “pack” extra packets in a burst without relinquishing ownership of the medium. A  
burst length timer is implemented which allows the Ethernet controller to continue to send packets  
until the timer expires (if packets are available for transmission).  
In the case where a transmitting station has more than one packet to send, it can transmit the first  
packet (extending to 512 bytes if necessary) and then begin the transmission of subsequent packets.  
Packet transmission can continue until either there are no more packets ready for transmission, or  
the burst timer has expired. The burst timer limit is specified as 8 KB.  
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The normal rules for IPG are followed during packet bursting after the first packet has met the  
minimum slot time requirements, with the exception that the Inter Frame Content (IFC) is  
extension symbols rather than IDLEs. Under some circumstances, it might be desirable to extend  
this IPG time during a burst. This can be done via the AIFS field in the AIT register. See Section  
13.4.35.  
1
8.5  
Auto-Negotiation and Link Setup  
Configuration of the link can be accomplished by several methods ranging from software forcing  
the link settings to Auto-Negotiation by the internal PHY. Section 8.6.1 describes the process of  
bringing the link up including configuration of the MAC and PHY, as well as the various methods  
of determining duplex and speed configuration.  
The PHY performs Auto-Negotiation per 802.3ab clause 40 and extensions to clause 28. Link  
resolution is obtained from the PHY after the link has been established via the MDIO interface, by  
the controller via specific input signals from the PHY or by the controller’s specific auto detection  
functions.  
Upon power up, or device reset via the RST# input, the controller initiates Auto-Negotiation based  
on the default settings in the Device Control and Transmit Configuration Word registers, as well as  
settings read from the EEPROM. If enabled in the EEPROM, the Ethernet controller will immedi-  
ately perform Auto-Negotiation.  
2
8.6  
Auto-Negotiation and Link Setup  
Configuration of the link can be accomplished by several methods ranging from software forcing  
the link settings to Auto-Negotiation by either the MAC (Internal Serdes mode) or the internal  
PHY (GMII/MII mode). The following sections describe the process of bringing the link up  
including configuration of the MAC and PHY, as well as the various methods of determining  
duplex and speed configuration.  
The process of determining link configuration differs slightly depending on the Ethernet controller  
type and version. In Internal Serdes mode, the MAC performs Auto-Negotiation per clause 37 of  
the 802.3z standard. The transceiver used in this mode (the SerDes) does not participate in the  
Auto-Negotiation process as all aspects of Auto-Negotiation are controlled by the MAC.  
For internal PHY mode, the PHY performs Auto-Negotiation per 802.3ab clause 40 and extensions  
to clause 28. Link resolution is obtained from the PHY after the link has been established via the  
MDI/O interface, by the Ethernet controller via specific input signals from the PHY, or by the  
Ethernet controller’s specific auto detection functions.  
The method for configuring the link between two link partners is highly dependent on the mode of  
operation as well as the functionality provided by the specific physical layer device (PHY or  
SerDes). For Internal Serdes mode, the Ethernet controller provides the complete 802.3z PCS  
function on-chip. For GMII/MII mode, the PCS and Auto-Negotiation functions are maintained  
within the PHY.  
1. 82541xx, 82547GI/EI, and 82540EP/EM only.  
2. Applicable to the 82546GB/EB, 82545GM/EM, and 82544GC/EI only.  
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The following section describes the link configuration process in the Internal Serdes for the  
82546GB/EB and 82545GM/EM (TBI mode for the 82544GC/EI) and internal PHY modes.  
8.6.1  
Link Configuration in Internal Serdes/TBI Mode1  
Internal Serdes for the 82546GB/EB and 82545GM/EM (TBI for the 82544GC/EI) Mode link  
configuration can be performed via the on-chip PCS function in the Ethernet controller. The  
hardware supports both hardware and software Auto-Negotiation methods for determining the link  
configuration, as well as allowing for manual configuration to force the link.  
Hardware Auto-Negotiation is the preferred method.  
8.6.1.1  
Link Speed  
Internal Serdes for the 82546GB/EB and 82545GM/EM (TBI for the 82544GC/EI) Mode is only  
defined for 1000 Mb/s operation. Other link speeds are not supported.  
When the 82546GB/EB and 82545GM/EM is in internal Serdes mode, the speed determination  
function is disabled and the Device Status register bits (STATUS.SPEED) bits indicate a value of  
10b for 1000 Mb/s.  
For the 82544GC/EI, when the TBI_MODE input is asserted for TBI mode, the speed  
determination function is disabled and the Device Status register bits (STATUS.SPEED) bits  
indicate a value of 10b for 1000 Mb/s.  
8.6.1.2  
Auto-Negotiation  
At power up, or Ethernet controller reset via the RST# input, it initiates Auto-Negotiation based on  
the default settings in the Device Control and Transmit Configuration Word registers, as well as  
settings read from the EEPROM. If enabled in the EEPROM, the Ethernet controller immediately  
performs Auto-Negotiation.  
TBI Mode Auto-Negotiation, as defined in clause 37 of the IEEE 802.3z standard, provides a  
protocol for two Ethernet controllers to advertise and negotiate a common operational mode across  
a Gigabit Ethernet link. The Ethernet controller fully supports the IEEE 802.3z Auto-Negotiation  
function when using the internal Serdes mode for the 82546GB/EB and 82545GM/EM or when  
using the TBI and on-chip PCS for the 82544GC/EI.  
TBI Mode Auto-Negotiation is used to determine the following information:  
• Duplex resolution  
• Flow control configuration  
Speed for Internal Serdes mode (TBI mode for the 82544GC/EI) is fixed at 1000 Mb/s, so speed  
settings in the Device Control register are unaffected by the Auto-Negotiation process.  
There are two implementations accessible in the design:  
1. A full hardware Auto-Negotiation implementation that does not require software intervention  
in order to successfully reach a negotiated link configuration.  
2. Software driven negotiation.  
1. TBI mode for the 82544GC/EI.  
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A set of registers is provided to facilitate either hardware or software Auto-Negotiation.  
The hardware supports both hardware and software Auto-Negotiation methods for determining  
link configuration as well as allowing for manual configuration to force the link. The IEEE 802.3z  
specification defines a set of resources that software can use to control a hardware implementation  
of Auto-Negotiation, but this definition is sub-optimal for Internal Serdes mode (TBI mode for the  
82544GC/EI) and hardware Auto-Negotiation is the preferred method.  
In addition, it specifies optional resources that exist only to support the exchange of “Next Pages”,  
something that is not required for the Ethernet controller. The hardware defined in this  
specification accepts and exchanges next pages in Internal Serdes mode (TBI mode for the  
82544GC/EI), but does so by dropping all incoming next pages and sending only null next pages.  
The Ethernet controller can only send null next pages when in hardware Auto-Negotiation. A full  
next page exchange can take place if software performs Auto-Negotiation.  
The Ethernet controller fully complies with IEEE 802.3z with respect to next page exchange in that  
both link partners must request next page exchange in order to do so.  
8.6.1.3  
Hardware Auto-Negotiation  
Hardware supports negotiation of the link configuration per clause 37 of the 802.3z standard. This  
is accomplished by the exchange of /C/ ordered sets that contain the txConfigWord register values  
from TXCW in the third and fourth symbols of the ordered sets.  
Bits FD and LU of the Device Status register (STATUS), and ANC of the RXCW register provide  
status information regarding the negotiated link.  
Auto-Negotiation can be initiated by the following:  
• LRST transition from 1b to 0b in CTRL register  
• ANE transition from 0b to 1b in TXCW register  
• Receipt of /C/ ordered set during normal operation  
• Receipt of different value of the /C/ ordered set during the negotiation process  
• Transition from loss of synchronization to synchronized state (if ANE is enabled)  
Resolution of the negotiated link determines device operation with respect to flow control  
capability and duplex settings. These negotiated capabilities override advertised and S/W  
controlled device configuration.  
Software must configure the TXCW.txConfigWord field to the desired advertised base page. The  
bits in the Device Control register are not mapped to the txConfigWord field in hardware until after  
Auto-Negotiation completes. The Figure 8-2 and Figure 8-3 show txConfigWord and the mapping  
to the Config_reg Base Page encoding per clause 37 of the standard. Table 8-2 lists the bit contents.  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
4
3
2
1
0
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
Np  
AS  
PS  
Hd  
Fd  
Figure 8-2. TXCW.txConfigWord  
15  
14  
13  
12  
11  
10  
9
8
7
6
5
4
3
2
1
0
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
RS  
V
Np  
Ack  
Rf2  
Rf1  
Ps2 Ps1  
Hd  
Fd  
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Figure 8-3. 802.3z Advertised Base Page Mapping  
Table 8-2. Bits Content in TXCW.txConfigWord  
Bit  
Description  
Next Page Indication  
Np  
When set indicates a request for next page exchange  
Asymmetric Pause Connection is Desired  
When set, results in independent enabling/disabling of the flow control  
receive and transmit. When cleared, results in symmetric enabling/disabling  
of the flow control receive and transmit  
AS  
Pause Function  
When set, indicates that the Ethernet controller is capable and intends to  
stop upon reception of 802.3x flow control Pause packets.  
When cleared, indicates that the Ethernet controller is not capable, or does  
not intend to stop upon reception of flow control Pause packets.  
PS  
HD  
Half-Duplex Ability  
When set, indicates that the Ethernet controller is capable of working in  
half-duplex mode of operation  
Full Duplex Ability  
FD  
When set, indicates that the Ethernet controller is capable of working in full-  
duplex mode of operation  
Reserved  
Should be written as 0b  
RSV  
The reserved bits should be written as zero. The remote fault bits [13:12] can be set by software to  
indicate remote fault type to the link partner if desired. The AS and PS bits are used for  
advertisement of PAUSE frame operation. Refer to clause 37 of the 802.3z specification for details.  
8.6.1.4  
Software Auto-Negotiation  
Auto-Negotiation can also be performed by software with TXCW.ANE set to 0b. Data stored in the  
txConfigWord field is transmitted during the configuration process. Software should not (in  
general) read back the contents of this register.  
If hardware loses receive synchronization, the contents of the TXCW register changes and during  
the time of the change, the value read back can be inconsistent. In the absence of loss of  
synchronization, the value read back is stable and equal to the last written value.  
Software controls the negotiation process by writing the appropriate values to the txConfigWord  
and transmitting /C/ ordered sets by setting txConfig (in TXCW) to 1b. Software must monitor the  
RXCW register for status of the negotiation process and respond via writes to the TXCW register  
appropriately.  
The software algorithm must follow the state machine implementation of sub-clause 37.3.1.5 of  
IEEE 802.3z, Figure 37-6. The link timer specification is 10 ms (+10 ms/-0 ms). In some systems,  
response time for the S/W implementation can make it difficult to meet this requirement if system  
utilization is high due to latencies on the PCI bus.  
For more information, refer to the register definitions for TXCW and RXCW in Sections 13.4.13  
and 13.4.14, respectively.  
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8.6.1.5  
Forcing Link  
In cases where the Ethernet controller is connected to a non-Auto-Negotiating link partner, the  
hardware allows for manual configuration of the link via the Device Control register (CTRL).  
Forcing link can be accomplished by software writing a 1b to CTRL.SLU which forces the TBI  
PCS logic into a link up state if the LOS input is not asserted. Setting the SLU bit enables the MAC  
to communicate with the internal SerDes and allows recognition of the LOS signal. If auto-  
negotiation is enabled (TXCW.ANE = 1b) Set Link Up is ignored. The LINK UP# output, as well  
as internal status logic, indicates link status.  
The TXCW.ANE bit must be set to logic 0b to allow for forcing link. When link is forced via the  
CTRL.SLU bit, the link cannot come up unless the LOS input is deasserted, implying there is a  
valid signal being received by the optics or the SerDes.  
An interrupt bit, RXCFG, flags software that the hardware is receiving configuration symbols (/C/  
codes). Software should mask (enable) this interrupt when forcing link. When the link is forced, the  
link partner can begin to Auto-Negotiate based due to a reset or enabling of Auto-Negotiation. The  
reception of /C/ codes causes an interrupt to software and the proper hardware configuration can be  
set.  
8.6.2  
Internal GMII/MII Mode  
Link configuration in GMII/MII mode is generally determined by the PHY via Auto-Negotiation.  
The software driver must intervene in cases where a successful link is not negotiated or a  
programmer desires to manually configure the link. The following sections discuss the methods of  
link configuration for internal PHY mode.  
8.6.2.1  
Auto-Negotiation  
In GMII/MII mode, the PHY performs the Auto-Negotiation function. The operational details of  
this function are described in the IEEE P802.3ab draft standard.  
Auto-Negotiation provides a method for two link partners to exchange information in a systematic  
manner in order to establish a link configuration providing the highest common level of  
functionality supported by both partners. Once configured, the link partners exchange  
configuration information to resolve link settings such as:  
• Speed: 10/100/1000 Mb/s  
• Duplex: Full- or Half-  
• Flow Control Operation  
PHY specific information required for establishing the link is also exchanged, but is not relevant to  
the operation of the Ethernet controller.  
If flow control is enabled in the MAC, the settings for the desired flow control behavior must also  
be made by software in the PHY and Auto-Negotiation must be restarted. After Auto-Negotiation  
completes, the software driver must read the MII registers in the PHY to determine the resolved  
flow control behavior of the link and reflect these parameters in the Ethernet controller register  
(CTRL.TFCE and CTRL.RFCE).  
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Once PHY Auto-Negotiation is complete, the PHY asserts the link indication signal. Software  
MUST set the “set link up” bit in the Device Control Register (CTRL.SLU) before the Ethernet  
controller recognizes the link. Setting the SLU bit permits the MAC to recognize the LINK signal  
from the PHY, which indicates the PHY has gotten the link up, and to receive and transmit data.  
8.6.2.2  
Link Speed  
The speed of the link in GMII/MII mode can be determined by several methods with the Ethernet  
controller. These include:  
• Software forced configuration of link speed  
• Automatically detecting the Auto-Negotiated speed from the PHY  
• Direct indication of speed configuration from the PHY  
These methods are discussed in the following sections.  
8.6.2.2.1  
Forcing Speed  
There can be circumstances when the software driver must force the link speed of the Ethernet  
controller. This can occur when the link is manually configured.  
The software driver can force speed in the MAC by setting the CTRL.FRCSPD (force-speed) bit to  
1b, and then setting the speed bits in the Device Control register (CTRL.SPEED) to the desired  
speed setting. See Section 13.4.1 for details.  
When forcing the Ethernet controller to a specific speed configuration, the driver must also ensure  
the PHY is configured to a speed setting consistent with the MAC. This statement implies that  
software accesses to the PHY either force the speed, or read the MII management status register  
bits that indicate link speed within the PHY itself.  
Forcing the speed setting with CTRL.SPEED also can be accomplished by setting the  
CTRL_EXT.SPD_BYPS bit. This bit bypasses the internal clock switching logic, and gives  
complete control to the driver when the speed setting takes place. The CTRL.FRCSPD bit uses the  
internal clock switching logic, which delays the effect of the speed change.  
8.6.2.2.2  
Using Auto-Speed Detection (ASD)  
The Ethernet controller provides a method in hardware for automatically sensing the speed of the  
link by observing the receive clock signal generated by the PHY once the link is established. The  
Auto-Speed Detection (ASD) function is enabled via the ASDE bit in the Device Control register  
(CTRL.ASDE). ASD provides a method of determining the link speed without the need for  
software accesses to the MII management registers. ASD is not supported in Internal Serdes mode  
for the 82546GB/EB and 82545GM/EM or TBI mode for the 82544GC/EI.  
In internal PHY mode, the internal receive clock input operates at the byte rate of the link interface.  
By sensing this clock, the Ethernet controller makes a determination of the link speed and sets the  
proper configuration in the control registers without software intervention.  
The ASD function is initiated upon the assertion of a valid link by the PHY via an internal signal  
input. After the speed is detected, the Device Control and Device Status register bits are set and  
reflect the speed of the link. As described earlier, software must set the CTRL.SLU bit to allow the  
speed selection to take effect.  
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STATUS.ASDV [9:8], provides the results of speed status indication for diagnostics purposes  
regardless of whether the Auto-Speed Detection feature is enabled. This function is initiated with a  
write to the CTRL_EXT.ASDCHK bit. See Section 13.4.6 for details.  
8.6.2.2.3  
Automatic Detection of Link Speed using SPD-IND  
With the CTRL register configure as CTRL.FRCSPD = 0, the speed is reconfigured automatically  
each time a new linkup event is detected. This configuration is recommended why the PHY is  
configured for Auto-Negotiation.  
8.6.2.3  
Duplex  
The duplex configuration of the link is also resolved during the Auto-Negotiation process. As  
previously mentioned, the Ethernet controller supports both full- and half-duplex operation in  
internal PHY mode. When the PHY asserts its link signal to the MAC, it also communicates the  
duplex setting.  
Software can override the duplex setting via the CTRL.FD bit when the CTRL.FRCDPLX (force  
duplex) bit is set. If CTRL.FRCDPLX is 0b, the CTRL.FD bit is ignored.  
8.6.2.4  
MII Management Registers  
The software driver is required under some circumstances to read from, or write to, the MII  
management registers in the PHY. These accesses are performed via the MDIC registers. The MII  
registers allow the software driver to have direct control over the PHY’s operation, which includes:  
• Resetting the PHY  
• Setting preferred link configuration for advertisement during the Auto-Negotiation process  
• Restarting the Auto-Negotiation process  
• Reading Auto-Negotiation status from the PHY  
• Forcing the PHY to a specific link configuration  
• Extended capabilities  
The standard set of PHY management registers can be found in the IEEE P802.3ab standard.  
8.6.2.5  
Comments Regarding Forcing Link  
Forcing link in GMII/MII mode requires the software driver to configure both the MAC and the  
PHY in a consistent manner with respect to each other as well as the link partner. After  
initialization, the software driver configures the desired modes in the MAC, then accesses the PHY  
MII registers to set the PHY to the same configuration.  
In internal PHY mode, setting the CTRL.SLU bit forces a link up condition in the MAC. The  
duplex setting at this point should be forced by software on the CTRL.FD bit.  
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8.6.3  
Internal SerDes Mode1 Control Bit Resolution  
2
Tables 8-3, 8-4, and 8-5 list how on-chip Auto-Negotiation affects control bits in the Ethernet  
controller. Table 8-5 lists the case where software Auto-Negotiation is not performed and link is  
forced.  
1
Table 8-3. Internal Serdes Mode – Hardware Enabled  
TXCW.ANE = 1b  
Control Bit  
CTRL.FD  
Effect on Control Bits  
Ignored; duplex is set by priority resolution of TXCW and RXCW  
Ignored; it is not possible to force link configuration (ANE takes precedence)  
Set by priority resolution (read only)  
CTRL.SLU  
CTRL.RFCE  
CTRL.TFCE  
CTRL.SPEED  
STATUS.FD  
STATUS.LU  
STATUS.SPEED  
Set by priority resolution (read only)  
No impact; speed always 1000 Mb/s in Internal Serdesa mode  
Set by priority resolution  
Duplicate of RXCW.ANC (Auto-Negotiation complete)  
Internal SerDesa Mode is always 1000 Mb/s; fixed at 10b  
a.  
TBI for the 82544GC/EI.  
1
Table 8-4. Internal Serdes Mode – Software Enabled  
TXCW.ANE = 0b  
Control Bit  
CTRL.FD  
Effect on Control Bits  
Duplex is set by software priority resolution  
CTRL.SLU  
Set by software when Auto-Negotiation is complete.  
Set by software as a result of software priority resolution  
Set by software as a result of software priority resolution  
No impact; speed always 1000 Mb/s in Internal SerDesa mode  
Reflects the value of CTRL.FD  
CTRL.RFCE  
CTRL.TFCE  
CTRL.SPEED  
STATUS.FD  
STATUS.LU  
Reflects CTRL.SLU and internal link indication  
STATUS.SPEED Internal Serdesa Mode is always 1000 Mb/s; fixed at 10b  
a.  
TBI for the 82544GC/EI.  
1. TBI Mode for the 82544GC/EI.  
2. Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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1
Table 8-5. Internal Serdes Mode – Auto-Negotiation Skipped  
TXCW.ANE = 0b  
Control Bit  
CTRL.FD  
Effect on Control Bits  
Duplex is set by software for the desired mode of operation  
Set by software  
CTRL.SLU  
CTRL.RFCE  
CTRL.TFCE  
CTRL.SPEED  
STATUS.FD  
STATUS.LU  
STATUS.SPEED  
Set by software for the desired mode of operation  
Set by software for the desired mode of operation  
No impact; speed always 1000 Mb/s in Internal SerDesa mode  
Reflects the value of CTRL.FD  
Reflects CTRL.SLU and internal link indication  
Internal SerDesa Mode is always 1000 Mb/s; fixed at 10b  
a.  
TBI for the 82544GC/EI.  
8.6.4  
Internal PHY Mode Control Bit Resolution  
Tables 8-6, 8-7, 8-8, and 8-9 list how Auto-Negotiation affects control bits in the Ethernet  
Controller.  
Refer to IEEE 802.3z, clause 37 for information related duplex and flow control link resolution per  
the 802.3z Auto-Negotiation method. The Ethernet controller fully complies to the specified  
resolution functions.  
Table 8-6. GMII/MII Mode – PHY Speed Indication  
CTRL.FRCSPD = CTRL.ASDE = CTRL.FRCDPLX = 0b  
Control Bit  
CTRL.FD  
Effect on Control Bits  
Duplex is set per internal signal after link up assertion by PHY.  
Software should set to allow PHY to control.  
CTRL.SLU  
Must be set by software after reading flow control resolution from MII  
registers.  
CTRL.RFCE  
Must be set by software after reading flow control resolution from MII  
registers.  
CTRL.TFCE  
CTRL.SPEED  
STATUS.FD  
STATUS.LU  
Ignored; no impact on speed.  
Reflects the value of CTRL.FD as above.  
Reflects link status and SLU set.  
Speed status bits reflect speed resolved from speed indication inputs from  
PHY.  
STATUS.SPEED  
1. TBI for the 82544GC/EI.  
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Table 8-7. GMII/MII Mode – Auto-Speed Detection  
CTRL.FRCSPD = CTRL.FRCDPLX = 0b; CTRL.ASDE = 1b  
Control Bit  
CTRL.FD  
Effect on Control Bits  
Duplex is set per internal duplex indication after link up assertion by PHY.  
Software should set to allow PHY to control.  
CTRL.SLU  
Must be set by software after reading flow control resolution from MII  
registers.  
CTRL.RFCE  
Must be set by software after reading flow control resolution from MII  
registers.  
CTRL.TFCE  
CTRL.SPEED  
STATUS.FD  
Ignored; no impact on speed.  
Reflects the value of CTRL.FD as above.  
Reflects internal link status  
STATUS.LU  
STATUS.SPEED  
Speed status bits reflect speed resolved from ASD function.  
Table 8-8. GMII/MII Mode – Force Speed  
CTRL.FRCSPD = 1b; CTRL.FRCDPLX = 0b; CTRL.ASDE = X  
Control Bit  
CTRL.FD  
Effect on Control Bits  
Duplex is set per internal duplex indicates input after link up assertion by PHY.  
Software should set to allow PHY to control.  
CTRL.SLU  
Must be set by software after reading flow control resolution from MII  
registers.  
CTRL.RFCE  
CTRL.TFCE  
Must be set by software after reading flow control resolution from MII  
registers.  
CTRL.SPEED  
STATUS.FD  
Set by software to set speed of the MAC; must match PHY speed settings.  
Reflects the value of CTRL.FD.  
STATUS.LU  
Reflects internal link status.  
STATUS.SPEED  
Speed status bits reflect speed forced by CTRL.SPEED.  
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Table 8-9. GMII/MII Mode – Force Link  
CTRL.FRCSPD = CTRL.FRCDPLX = CTRL.SLU = 1b  
Control Bit  
CTRL.FD  
Effect on Control Bits  
Set by software.  
CTRL.SLU  
Set by software, and assumed PHY is also forced to assert link.  
Set by software for the desired mode of operation.  
Set by software for the desired mode of operation.  
Set by software.  
CTRL.RFCE  
CTRL.TFCE  
CTRL.SPEED  
STATUS.FD  
STATUS.LU  
STATUS.SPEED  
Reflects the value of CTRL.FD.  
Reflects CTRL.SLU set and internal link status.  
Reflects CTRL.SPEED.  
8.6.5  
Loss of Signal/Link Status Indication  
For the 82546GB/EB and 82545GM/EM, the internal LOS signal allows for indication of physical  
link status to the Ethernet controller’s MAC.  
For the 82544GC/EI, the LOS input is provided to allow for indication of physical link status to  
the Ethernet controller. When the 82544GC/EI is configured in TBI mode, the input is typically  
connected to the loss-of-signal connection from the optics while in internal PHY mode.  
If the LSC (Link Status Change) interrupt is enabled, the hardware posts an interrupt to be serviced  
by the software driver when the link goes up or down. See Section 3.4.3 for more details.  
1
8.6.5.1  
8.6.5.2  
Internal Serdes Mode  
When asserted, LOS indicates there is no activity on the fiber due to either an unplugged cable or a  
defective optical device. An assertion on LOS implies the link is not available and the hardware is  
disabled. This is true whether the link is forced by the Set Link Up bit (CTRL.SLU) or if the  
Ethernet controller is configured to perform Auto-Negotiation. When Auto-Negotiation is enabled,  
the Ethernet controller is forced to restart Auto-Negotiation but does not complete the negotiation  
process until the LOS is deasserted.  
Internal PHY Mode  
While in internal PHY mode, an internal signal provides status of the physical link as indicated by  
the PHY. Indication that the link is not up disables MAC operation. Upon determination of a valid  
link, the assertion of the internal link signal asserts the LSC interrupt (if enabled) to indicate to the  
software driver to check the link status.  
1. TBI mode for the 82544GC/EI.  
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8.7  
10/100 Mb/s Specific Performance Enhancements  
8.7.1  
Adaptive IFS1  
The Ethernet controller supports back-to-back transmit Inter-Frame-Spacing (IFS) of 960 ns in 100  
Mb/s operation and 9.6 s in 10 Mb/s operation. Although back-to-back transmission is normally  
desirable, sometimes it can actually hurt performance in half-duplex environments due to excessive  
collisions. Excessive collisions are likely to occur in environments where one station is attempting  
to send large frames back-to-back, while another station is attempting to send acknowledge (ACK)  
packets.  
The Ethernet controller contains an Adaptive IFS Throttle - AIT register (see Section 13.4.35) that  
enables the implementation of a driver-based adaptive IFS algorithm for collision reduction.  
Adaptive IFS throttles back-to-back transmissions in the transmit MAC and delays their transfer to  
the CSMA/CD transmit function. Normally, this register should be set to zero. However, if  
additional delay is desired between back-to-back transmits, then this register can be set with a  
value greater than zero. By setting this register with a higher value, collisions can be reduced in  
certain half-duplex environments, because the adapter is less aggressive in acquiring the wire, and  
therefore less likely to collide with another adapter that attempts to transmit after minimum IFS.  
Note: IFS and IPG (inter-packet gap) are equivalent terms and may be used interchangeably in this  
manual.  
The AIFS field provides a similar function to the IGPT field in the TIPG register (see Section  
13.4.34). However this Adaptive IFS throttle register counts in units of transmit clocks (which are  
8 ns, 80 ns, 800 ns for 10, 100, 1000 Mb/s mode respectively), and is 16 bits wide, thus providing a  
greater maximum delay value.  
Using values lower than a certain minimum (determined by the ratio of transmit clock to link  
speed), has no effect on back-to-back transmission. This is because the Ethernet controller does not  
start transmission until the minimum IEEE IFS (9.6 us at 10 Mb, 960 ns at 100 Mb, and 96 ns at 1  
Gb) has been met regardless of the value of Adaptive IFS. For example, if the Ethernet controller is  
configured for 100 Mb/s operation, the minimum IEEE IFS at 100 Mb/s is 960 ns. Setting AIFS to  
a value of 10 (decimal) would not affect back-to-back transmission time on the wire, because the  
800 ns delay introduced (10 * 80n s = 800 ns) is less than the minimum IEEE IFS delay of 960 ns.  
However, setting this register with a value of 20 (decimal), which corresponds to 1600 ns for the  
above example, would delay back-to-back transmits because the ensuing 1600 ns delay is greater  
than the minimum IFS time of 960 ns.  
It is important to note that this register has no effect on transmissions that occur immediately after  
receives or on transmissions that are not back-to-back (unlike the IPGR1 and IPGR2 values in the  
TIPG register described in Section 13.4.34). In addition, Adaptive IFS also has no effect on re-  
transmission timing (re-transmissions occur after collisions). Therefore, AIFS is only enabled in  
back-to-back transmission. The AIFS value is NOT additive to the TIPG.IPGT value; instead, the  
actual IPG equals the larger of AIFS and TIPG.IPGT.  
1. Not applicable to the 82541xx or 82547GI/EI.  
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8.7.2  
Flow Control  
Flow control as defined in IEEE specification 802.3x, as well as the specific operation of  
asymmetrical flow control defined by 802.3z, are supported. The following registers are defined  
for the implementation of flow control:  
Table 8-10. Flow Control Registers  
Register Name  
Description  
Flow Control Address Low, High (FCAL/H)  
6-byte flow control multicast address  
13-bit high water mark indicating receive  
buffer fullness  
Flow Control Receive Thresh Hi (FCRTH)  
16 bit timer value to include in transmitted  
PAUSE frame  
Flow Control Transmit Timer Value (FCTTV)  
Flow Control Type (FCT)  
16-bit field to indicate flow control type  
13-bit low water mark indicating receive  
buffer emptiness  
Flow Control Receive Thresh Lo (FCRTL)  
Flow control is implemented as a means of reducing the possibility of receive buffer overflows  
which result in the dropping of received packets, and allows for local control of network  
congestion levels. This can be accomplished by sending an indication to a transmitting station of a  
nearly-full receive buffer condition at a receiving station.  
The implementation of asymmetric flow control allows for one link partner to send flow control  
packets while being allowed to ignore their reception. For example, not required to respond to  
PAUSE frames.  
For the 82541xx and 82547GI/EI, there are two forms of flow control that can be established via  
auto-negotiation: symmetric and asymmetric. Symmetric flow control is for point-to-point links;  
asymmetric for hub-to-end-node connections. Symmetric flow control allows either node to flow-  
control the other. Asymmetric flow control allows a repeater or switch to flow-control a DTE, but  
not vice versa  
8.7.3  
MAC Control Frames & Reception of Flow Control Packets  
Three comparisons are used to determine the validity of a flow control frame:  
1. A match on the 6-byte multicast address for MAC Control Frames or to the station address of  
the device (Receive Address Register 0).  
2. A match on the type field.  
3. A comparison of the MAC Control Opcode field.  
Standard 802.3x defines the MAC Control Frame multicast address as 01_80_C2_00_00_01h. This  
address must be loaded into the Flow Control Address Low/High registers (FCAL/H).  
The Flow Control Type register (FCT) contains a 16-bit field that is compared against the flow  
control packet’s type field to determine if it is a valid flow control packet: XON or XOFF. 802.3x  
reserves this value as 8808h. This number must be loaded into the Flow Control Type (FCT)  
register.  
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The final check for a valid PAUSE frame is the MAC Control Opcode. At this time only the  
PAUSE control frame opcode is defined. It has a value of 0001h.  
Frame based flow control differentiates XOFF from XON based on the value of the PAUSE timer  
field. Non-zero values constitute XOFF frames while a value of zero constitutes an XON frame.  
Values in the timer field are in units of slot time. A “slot time” is hard wired to 64 byte times, or  
512 ns.  
Note: “S” is the Start-of-Packet delimiter and “T” is the first part of the End-of-  
Packet delimiters for 802.3z encapsulation.  
Figure 8-4. 802.3x MAC Control Frame Format  
The receiver is enabled to receive flow control frames if flow control is enabled through the RFCE  
bit in the Device Control register (CTRL). Software sets this bit consistently with the advertised  
capability in the Transmit Configuration Word Register (TXCW).  
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Flow control capability must be negotiated between link partners via the Auto-Negotiation process.  
The Auto-Negotiation process can modify the value of these bits based on the resolved capability  
between the local device and the link partner.  
Once the receiver has validated the reception of an XOFF, or PAUSE frame, the Ethernet controller  
performs the following:  
• Increment the appropriate statistics register(s)  
• Set the TXOFF bit in the Device Status Register (STATUS)  
• Initialize the pause timer based on the packet’s PAUSE timer field  
• Disable packet transmission or schedule the disabling of transmission after the current packet  
completes.  
Resumption of transmission can occur under the following conditions:  
• Expiration of the PAUSE timer  
• Reception of on XON frame (a frame with its PAUSE timer set to 0b)  
Either condition clears the STATUS.TXOFF bit and transmission can resume. Hardware records  
the number of received XON frames in the XONRXC counter.  
8.7.4  
Discard PAUSE Frames and Pass MAC Control Frames  
Note: When receive flow control is enabled (CTRL.RFCE) is 1b, the following special filtering is  
performed on PAUSE and MAC Control frames. When receive flow control is disabled, these  
frames are filtered like any other frames and the rest of this section can be ignored.  
Two bits in the Receive Control register (RCTL) are implemented specifically for control over  
receipt of PAUSE and MAC control frames. These bits are Discard PAUSE Frames (DPF) and Pass  
MAC Control Frames (PMCF). See Section 13.4.22 for DPF and PMCF bit definitions.  
The DPF bit forces the discarding of any valid PAUSE frame addressed to the Ethernet controller’s  
station address. If the packet is a valid PAUSE frame and is addressed to the station address  
(receive address [0]), the Ethernet controller does not pass the packet to host memory if the DPF bit  
is set to logic high. The DPF bit does not affect pause frames that are addressed to the MAC control  
frame multicast address (01-80-C2-00-00-01). These frames are DMA’ed if they pass standard  
address filtering, including receive address 1 to 15, multicast hash filtering, or the Multicast  
Promiscuous bit is enabled. TheDPF has no affect on PAUSE operation, only the DMA function.  
The PMCF bit allows for the passing of any valid MAC control frames to the system which do not  
have a valid PAUSE opcode. In other words, the frame can have the correct MAC control frame  
multicast address (or the MAC station address) as well as the correct type field match with the FCT  
register, but does not have the defined PAUSE opcode of 0001h. Frames of this type are transferred  
to host memory when PMCF is logic high. The results of this filter are logically ORed into the  
standard filters, so even if PMCF is 0b, any MAC control frame that isn't a PAUSE frame that  
passes standard address filtering is DMA’ed  
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8.7.5  
Transmission of PAUSE Frames  
Transmitting PAUSE frames is enabled by software writing a 1b to the CTRL.TFCE bit. This bit is  
mapped to bit 8 of the TXCW txConfigWord field. (ASM_DIR bit).  
Similar to the reception flow control packets described earlier, XOFF packets can be transmitted  
only if this configuration has been negotiated between the link partners via the Auto-Negotiation  
process. In other words, the setting of this bit indicates the desired configuration. The resolution of  
the Auto Negotiation process is discussed in Sections 8.6.3 and 8.6.4.  
The contents of the Flow Control Receive Threshold High register (FCRTH) determine at what  
point hardware transmits a PAUSE frame. Hardware monitors the fullness of the receive FIFO and  
compares it with the contents of FCRTH. When the threshold is reached, hardware sends a PAUSE  
frame with its pause time field equal to FCTTV. Once the receive buffer fullness reaches the low  
water mark, hardware sends an XON message (a PAUSE frame with a timer value of 0b). Software  
enables this capability with the XONE field of the FCRTL.  
Hardware sends one more PAUSE frames if it has previously sent one and the FIFO overflows (so  
the threshold must not be set greater than the FIFO size). This function is intended to minimize the  
number of packets dropped if the first PAUSE frame does not reach its target.  
Transmitting Flow Control frames should only be enabled in full duplex mode per the IEEE 802.3  
standard. Software should ensure that the transmission of flow control packets is disabled when the  
Ethernet controller is operating in half-duplex mode.  
8.7.6  
Software Initiated PAUSE Frame Transmission  
The Ethernet controller has the added capability to transmit an XOFF frame through software. This  
function is accomplished by software writing a 1b to the SWXOFF bit of the Transmit Control  
register (TCTL). Once this bit is set, hardware initiates the transmission of a PAUSE frame in a  
manner similar to that automatically generated by hardware.  
The SWXOFF bit is self clearing after the PAUSE frame has been transmitted.  
The state of the CTRL.TFCE bit or the negotiated flow control configuration does not affect  
software generated PAUSE frame transmission.  
Software sends an XON frame by programming a zero in the PAUSE timer field of the FCTTV  
register.  
Caution: Use of SWXOFF is not recommended due to security concerns.  
8.7.7  
External Control of Flow Control Operation1  
Transmitting XOFF and XON frames can be triggered by external pins. When enabled through  
FCRTH.XFCE, the XOFF and XON inputs can be used to provide external effective threshold  
information that initiate XOFF and XON transmission, respectively.  
1. 82544GC/EI only.  
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When the XOFF signal is asserted high, the device transmits a single XOFF frame. The assertion of  
I_XON (after deassertion of XOFF) initiates an XON frame transmission if enabled by  
FCRTL.XONE. The assertion/deassertion of XON is required between assertions of XOFF in order  
to send another XOFF frame, providing a built-in hysteresis mechanism.  
Output signals are also provided from the 82544GC/EI to indicate the device is either above the  
programmed flow control high threshold or below the flow control low threshold (ABV_HI and  
BLW_LOW respectively).  
Flow control transmission must also be enabled through CTRL.TFCE.  
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802.1q VLAN Support  
9
The PCI/PCI-X Family of Gigabit Ethernet Controllers provide several specific mechanisms to  
support 802.1q VLANs:  
• Optional adding (for transmits) and stripping (for receives) of IEEE 802.1q VLAN tags  
• Optional ability to filter packets belonging to certain 802.1q VLANs  
Note: The 82541ER Ethernet controller does not support VLAN tags.  
9.1  
802.1q VLAN Packet Format  
Table 9-1 compares the format of an untagged 802.3 Ethernet packet with an 802.1q VLAN tagged  
packet. The CRC for the 802.1q tagged frame is re-computed, so that it covers the entire tagged  
frame including the 802.1q tag header.  
Table 9-1. VLAN Packet Format Comparison  
802.1q VLAN  
802.3 Packet  
#Octets  
#Octets  
Packet  
DA  
SA  
6
DA  
SA  
6
6
6
Type/Length  
Data  
2
46-1500  
4
8021.q Tag  
Type/Length  
Data  
4
2
46-1500  
4
CRC  
CRC*  
Maximum frame size for a standard 803.3ac (802.1q VLAN and/or 802.1p priority) packet is 1522  
octets as opposed to 1518 octets for a normal 802.3 Ethernet packet. If jumbo frames are used,  
enabling 802.3ac adds 4 bytes to the packet to accommodate the q-tag. If multiple descriptors are  
required for a transmit, the q-tag information for the packet is extracted from only the last  
descriptor of the packet. VLAN tagging is supported independently of packet size.  
9.1.1  
802.1q Tagged Frames  
For 802.1q, the Tag Header field consists of four octets containing the Tag Protocol Identifier  
(TPID) and Tag Control Information (TCI), each utilizing 2 octets. The first 16 bits of the tag  
header make up the TPID. It contains the “protocol type” which identifies the packet as a valid  
802.1q tagged packet.  
The two octets making up the TCI contain three fields (see Table 9-2 for details):  
• User Priority (UP)  
• Canonical Form Indicator (CFI). The CFI should be 0b for transmits. For receives, the  
Ethernet controller has the capability to filter out packets that have this bit set. See the CFIEN  
and CFI bits in the RCTL as described in Section 13.4.22.  
• VLAN Identifier (VID)  
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Table 9-2. 802.1q Tagged Frames  
Octet 1  
UP  
Octet 2  
CFI  
VID  
9.2  
Transmitting and Receiving 802.1q Packets  
Since the 802.1q tag is only four bytes, adding and stripping of tags can done completely in  
software. (For transmits, software inserts the tag into packet data before it builds the transmit  
descriptor list, and for receives, software strips the four byte tag from the packet data before  
delivering the packet to upper layer software.)  
However, because adding and stripping of tags in software results in more overhead for the host,  
the Ethernet controller has additional capabilities to add and strip tags in hardware, as discussed in  
the following two sections.  
9.2.1  
9.2.2  
Adding 802.1q Tags on Transmits  
Software can command the Ethernet controller to insert an 802.1q VLAN tag on a per packet basis.  
If CTRL.VME is set to 1b, and the VLE bit in the transmit descriptor is set to 1b, then the Ethernet  
controller inserts a VLAN tag into the packet that it transmits over the wire. The Tag Protocol  
Identifier (TPID) field of the 802.1q tag comes from the VLAN Ether Type (VET) register, and the  
Tag Control Information (TCI) of the 802.1q tag comes from the special field of the transmit  
descriptor (TDESC.SPECIAL).  
Stripping 802.1q Tags on Receives  
Software can instruct the Ethernet controller to strip 802.1q VLAN tags from received packets. If  
the CTRL.VME bit is set to 1b, and the incoming packet is an 802.1q VLAN packet (its Ethernet  
Type field matched the VET register), then the Ethernet controller strips the 4-byte VLAN tag from  
the packet, and stores the TCI in the Special field of the receive descriptor.  
The Ethernet controller also sets the VP bit in the receive descriptor to indicate that the packet had  
a VLAN tag that was stripped. If the CTRL.VME bit is not set, the 802.1q packets can still be  
received if they pass the receive filter. In this case, the VLAN tag is not stripped and the VP bit is  
not set. Refer to Table 9-3 for more information regarding receive packet filtering.  
9.3  
802.1q VLAN Packet Filtering  
VLAN filtering is enabled by setting the RCTL.VFE bit to 1b. If enabled, hardware compares the  
type field of the incoming packet to a 16-bit field in the VLAN EtherType (VET) register. If the  
VLAN type field in the incoming packet matches the VET register, the 802.1q VLAN packet is  
then compared against the VLAN Filter Table Array (VFTA) for acceptance.  
The Virtual LAN ID field indexes a 4096 bit vector. If the indexed bit in the vector is 1b, there is a  
Virtual LAN match. Software can set the entire bit vector to 1b’s if the node does not implement  
802.1q filtering.  
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802.1q VLAN Support  
In summary, the 4096 bit vector is composed of 128 32-bit registers. Matching to this bit vector  
follows the same algorithm as indicated in Section 13.5.1 for Multicast Address filtering. The  
VLAN Identifier (VID) field consists of 12 bits. The upper 7 bits of this field are decoded to  
determine the 32-bit register in the VLAN Filter Table Array to address and the lower 5 bits  
determine which of the 32 bits in the register to evaluate for matching.  
Two other bits in the Receive Control register (see Section 13.4.22), CFIEN and CFI, are also used  
in conjunction with 802.1q VLAN filtering operations. CFIEN enables the comparison of the value  
of the CFI bit in the 802.1q packet to the Receive Control register CFI bit as an acceptance criteria  
for the packet.  
Note: The VFE bit does not affect whether the VLAN tag is stripped. It only affects whether the VLAN  
packet passes the receive filter.  
Table 9-3 lists reception actions according to control bit settings.  
Table 9-3. Packet Reception Decision Table  
Is  
packet  
802.1q?  
CTRL.  
VME  
RCTL.  
VFE  
ACTION  
No  
X
0
X
0
Normal packet reception.  
Receive a VLAN packet if it passes the standard filters (only). Leave the  
packet as received in the data buffer. Clear the VP bit in the receive  
descriptor.  
Yes  
Receive a VLAN packet if it passes the standard filters and the VLAN  
filter table. Leave the packet as received in the data buffer (the VLAN  
tag is not stripped). Clear the VP bit in the receive descriptor.  
Yes  
Yes  
0
1
1
0
Receive a VLAN packet if it passes the standard filters (only). Strip off  
the VLAN information (four bytes) from the incoming packet and store in  
the descriptor. Set the VP bit in the receive descriptor.  
Receive a VLAN packet if it passes the standard filters and the VLAN  
filter table. Strip off the VLAN information (four bytes) from the incoming  
packet and store in the descriptor. Set the VP bit in the receive  
descriptor.  
Yes  
1
1
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Configurable LED Outputs  
10  
1
10.1  
Configurable LED Outputs  
The PCI/PCI-X Family of Gigabit Ethernet Controller’s MAC implements four output drivers  
intended for driving external LED circuits. Each MAC’s four LED outputs can be individually  
configured to select the particular event, state, or activity that is indicated on that output. In  
addition, each LED can be individually configured for output polarity as well as for blinking vs.  
non-blinking (steady-state) indication.  
The configuration for LED outputs is specified via the LEDCTL register. In addition, the  
hardware-default configuration for two of the LED outputs, LED0/LINK_UP# and LED2/  
LINK100# can be specified via EEPROM fields, thereby supporting LED displays configurable to  
a particular OEM preference.  
10.1.1  
Selecting an LED Output Source  
Each of the four LED indications can be independently configured. The LEDCTL register MODE  
field corresponding to each LED selects the expression generating the LED output. The LED  
outputs are, by default, active low; it is assumed they are connected to the negative side (cathode)  
of an external LED. They will, by default, output a low value upon the assertion of the event (such  
as COLLISION) or state (such as LINK1000#) selected. Note that the active sense of the LED  
outputs can be inverted). See Section 10.1.2 for details.  
LINK_UP  
ACTIVITY  
COLLISION  
EXTERNAL  
LED  
(OPTIONAL)  
BLINK  
CONTROL  
CIRCUIT  
LED  
OUTPUT  
DRIVER  
(OPTIONAL)  
POLARITY  
INVERSION  
VCC/LED_OFF  
GND/LED_ON  
Figure 10-1. Selecting an LED Output Source  
1. Section 10 does not apply to the 82544GC/EI.  
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Configurable LED Outputs  
LED outputs can be based on the following expressions:  
• LINK_UP is asserted while link of any speed is maintained  
• LINK_10 indicates link at 10 Mbps  
• LINK_100 indicates link at 100 Mbps  
• LINK_1000 indicates link at 1000 Mbps  
• LINK_100/1000 indicates link at either 100 or 1000 Mbps  
• LINK_10/1000 indicates link at either 10 or 1000 Mbps  
• ACTIVITY is asserted when link is established and packets are being transmitted or received  
• LINK/ACTIVITY is asserted when link is established but there is NO transmit or receive  
activity  
• COLLISION is asserted each time a collision is observed  
• PAUSED is asserted while the Ethernet controller’s transmitter is paused due to flow control  
• PCIX_MODE is asserted when the Ethernet controller is in PCI-X mode (versus PCI mode)  
• FULL_DUPLEX is asserted when the link is configured for full duplex operation  
• BUS_SPEED is asserted in PCI 66 MHz or PCI-X 133 MHz configurations (high-speed  
operation)  
• BUS_SIZE is asserted in 64-bit PCI or PCI-X configurations  
• LED_ON is always asserted (low); LED_OFF is always deasserted (high)  
10.1.2  
Polarity Inversion  
The LEDCTL.IVRT field enables the selected LED source to be optionally inverted. This can be  
used to drive external circuitry where an active high indication of one of the selectable states/  
events is required (such as multi-color LED circuits).  
Note: Polarity inversion (LEDCTL.IVRT = 1b) and blinking (LEDCTL.BLINK = 1b) at the same time  
for a given LED is not recommended. Introducing additional polarity inversion on a selected state/  
event while blink-control is also enabled can produce nonsensical LED behavior (such as blinking  
LED’s during periods of NO activity or when link is down).  
10.1.3  
Blink Control  
Each LED’s output circuitry also includes a blink-control circuit that can additionally be enabled.  
The blink control circuitry turns its output sequentially on (low) for 200 ms, then off for another  
200 ms, each time its input is active/asserted. The LEDCTL.BLINK field controls whether a blink  
circuit is enabled for an LED output.  
The blink control is especially useful for ensuring that certain brief events, such as momentary  
ACTIVITY or COLLISION events, cause LED transitions which are sufficiently visible to a  
human eye. The circuit re-evaluates after each on/off blink cycle, ensuring a continuous blink  
pattern throughout periods of continuous event/state assertion (such as heavy ACTIVITY periods  
or long PAUSED times).  
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Note: It is especially important to note with respect to the blink-control circuit that:  
• the blink circuit, when enabled, exists as the LAST stage of the LED circuitry, after any  
(optional) signal inversion  
• the blink sequence occurs when the circuit input is asserted low  
As a result, it is possible to select combinations of IVRT and BLINK which do not make sense or  
produce unexpected results, such as examples previously noted. It is recommended that BLINK  
only be selected for indicating ACTIVITY, COLLISION, PAUSED, or the combination LINK/  
ACTIVITY signal. events/states, and that IVRT = 0b when blink is selected.  
Note: Selecting the LEDCTL.MODE = LINK/ACTIVITY with BLINK = 1b selects a unique LED  
output expression (this configuration is meaningful ONLY when IVRT inversion is disabled). In  
this configuration, the LED is off (output high) if there is no LINK, on if there is LINK but no  
ACTIVITY, and blinking if there is LINK with ACTIVITY.  
LINK_UP  
(LINK & NO ACTIVITY)  
TOGGLING DURING ACTIVITY  
ACTIVITY  
EXTERNAL  
LED  
LED  
OUTPUT  
DRIVER  
BLINK  
CONTROL  
CIRCUIT  
Figure 10-2. Blink Control  
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PHY Functionality and Features 11  
11.1  
Auto-Negotiation  
Auto-Negotiation between the PCI/PCI-X Family of Gigabit Ethernet Controllers and its link  
partner is performed by the PHY. Under normal, expected operating conditions, the MAC  
automatically establishes common speed and duplex settings via the PHY. This section details PHY  
configuration features involved in the auto-negotiation process.  
11.1.1  
Overview  
Auto-Negotiation by the PHY is initiated upon any of the following conditions:  
• Power-up reset (copper and fiber)  
• PHY detects loss of link (copper and fiber)  
• PHY detects re-appearance of energy on the link (copper and fiber)  
• MAC control of PHY power-management is enabled (CTRL.EN_PHY_PWR_MGMT = 1b  
and MAC transitions to low power state (D3) where continued PHY operation required for  
wakeup/manageability (copper and fiber)  
• PHY hardware reset asserted using the MAC CTRL.PHY_RST bit (copper only)  
• PHY soft-reset initiated via the PHY Control Register (bit 15, copper only)  
• Explicit Auto-Negotiation Re-Start initiated via the PHY Control Register (bit 9, copper only)  
• Explicit transition of PHY from internal IEEE power-down to normal mode via the PHY  
Control Register (bit 11, copper only)  
• Explicit transition of PHY from internal IEEE power-down to normal mode via the PHY  
Control Register by setting CTRL.LRST = 1 and TXCW.ANE = 1 (fiber only)  
Hardware defaults for the PHY configurations enable the PHY to advertise its full 1000BASE-T  
1
and 1000BASE-X capability, and to auto-negotiate to the best possible operation without any  
software intervention required. If the remote device does not have Auto-Negotiation capability, the  
Ethernet controller PHY uses the parallel detect function to determine the speed of the remote  
device for 100BASE-TX and 10BASE-T modes. Under certain circumstances, it might be  
desirable to configure auto-negotiation options to restrict certain behavior. For example, operate in  
2
half-duplex mode only.  
Note: Any PHY auto-negotiation options configured by software are only persistent while the LAN  
power (indicated by LAN_PWR_GOOD) remains available. Following a complete loss of power,  
the PHY reverts to auto-negotiation using its hardware-defaults.  
1. 1000 half-duplex not supported.  
2. TXCW and RXCW registers are used for fiber auto-negotiation advertising. For fiber, the MAC can be forced to 1000 full-duplex when  
connected to a non-auto-negotiating fiber switch.  
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11.1.2  
Next Page Exchanges  
If 1000BASE-T mode is advertised, then the Ethernet controller PHY automatically sends the  
appropriate next pages to advertise the capability and negotiate master/slave mode of operation. If  
a developer does not want to transmit additional next pages, the next page bit (PCI-Config Register  
bit 15) can be set to 0b and the software need take no further action.  
If next pages in addition to the ones required for 1000BASE-T are needed, then the software can  
set Auto-Negotiation Expansion Register bit 15 to 1b, and send and receive additional next pages  
via the Next Page Transmit Register (NPT) and Link Partner Next Page Register (LPN),  
respectively. The PHY stores the previous results from the Link Partner Next Page Register (LPN)  
in internal registers so that new next pages can overwrite the Link Partner Next Page Register  
(LPN).  
Note: 1000BASE-T next page exchanges are automatically handled without any software intervention,  
regardless of whether or not additional next pages are sent.  
11.1.3  
Register Update  
Changes to PHY Control Register bits 6, 8, 12, and 13, and PHY Specific Control Register bits 3,  
4, 6:5, 9:8 and 11, do not take effect unless one of the following takes place (copper only):  
• PHY soft reset (PHY Control Register bit 15)  
• Restart Auto-Negotiation (PHY Control Register bit 9)  
• Transition of PHY from IEEE power-down to normal operation (PHY Control Register bit 11)  
• The link goes down  
To enable or disable Auto-Negotiation, PHY Control Register bit 12 should be changed  
simultaneously with either PHY Control Register bits 15 or 9. For example, to disable Auto-  
Negotiation and force 10BASE-T half-duplex mode, the PHY Control Register should be written  
with 8000h.  
To disable Auto-Negotiation (fiber only), set TXCW.ANE = 0.  
The Auto-Negotiation Expansion Register and the 1000BASE-T Control Register are internally  
latched once every time the Auto-Negotiation enters the Ability Detect state in the arbitration state  
machine. As a result, a write to the Auto-Negotiation Expansion Register or the 1000BASE-T  
Control Register has no effect once the PHY begins to transmit Fast Link Pulses (FLPs). This  
guarantees that sequences of FLPs transmitted are consistent with one another.  
The Next Page Transmit Register is treated similarly to the Auto-Negotiation Expansion Register  
and the 1000BASE-T Control Register during additional next page exchanges.  
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11.1.4  
Status  
Once the PHY completes auto-negotiation, it updates the various statuses in the PHY Status  
Register, Link Partner Ability Register (Base Page), Auto-Negotiation Expansion Register, and  
1000BASE-T Status Register. For 1000BASE-T operation, the Auto-Negotiation Expansion  
Register and the Link Partner Ability Register (Base Page) are updated. Speed, duplex, page  
received, and Auto-Negotiation completion statuses are also available in the PHY Specific Status  
Register (PSTATUS) and the PHY Interrupt Status Register (PINTS).  
For fiber, the CTRL.STATUS register will reflect link status.  
Assuming normal MAC configuration, the MAC status register STATUS reports bits SPEED, FD  
(duplex/half indication), and LU (link up status) shortly after the PHY (or MAC, for fiber)  
completes auto-negotiation.  
11.2  
MDI/MDI-X Crossover (copper only)  
The Ethernet controller PHY automatically determines whether or not it needs to cross over  
between pairs as shown in the following table so that an external crossover cable is not required. If  
the PHY interoperates with a device that cannot automatically correct for crossover, the Ethernet  
controller PHY makes the necessary adjustment prior to commencing Auto-Negotiation. If the  
PHY operates with a device that implements MDI/MDI-X crossover, a random algorithm as  
described in IEEE 802.3 clause 40.4.4 determines which device performs the crossover.  
When the Ethernet controller PHY interoperates with legacy 10BASE-T devices that do not  
implement Auto-Negotiation, the PHY follows the same algorithm as described above since link  
pulses are present. However, when interoperating with legacy 100BASE-TX devices that do not  
implement Auto-Negotiation (link pulses are not present), the Ethernet controller PHY uses signal-  
detection to determine whether to crossover.  
Auto MDI/MDI-X crossover is the default hardware configuration, but can be disabled via the  
PHY Specific Control Register bits 6:5 (PSCON).  
The pin mapping in MDI/MDI-X modes are as follows:  
Pin  
MDI  
MDIX  
1000BASE-T 100BASE-TX  
10BASE-T  
TX +/-  
1000BASE-T 100BASE-TX  
10BASE-T  
RX +/-  
MDI[0]+/-  
MDI[1]+/-  
MDI[2]+/-  
MDI[3]+/-  
BI_DA +/-  
BI_DB +/-  
BI_DC +/-  
BI_DD +/-  
TX +/-  
BI_DB +/-  
BI_DA +/-  
BI_DD +/-  
BI_DC +/-  
RX +/-  
TX +/-  
RX +/-  
unused  
unused  
RX +/-  
TX +/-  
unused  
unused  
unused  
unused  
unused  
unused  
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11.2.1  
Polarity Correction (copper only)  
The Ethernet controller PHY automatically corrects for polarity errors on the receive pairs in  
1000BASE-T and 10BASE-T modes. In 100BASE-TX mode, the polarity does not matter.  
In 1000BASE-T mode, receive polarity errors are automatically corrected based on the sequence of  
the symbols. Once the descrambler is locked, the polarity is also locked on all pairs. The polarity  
becomes unlocked only when the receiver loses lock.  
11.2.2  
10/100 Downshift (82540EP/EM Only)  
Gigabit speed operation requires a 4-pair cable to operate. Some existing cables have only two  
pairs. Other cables might have 4 pairs, but one might be broken, leaving three working pairs. Over  
two or three pairs, two gigabit link partners might be able to successfully auto-negotiate 1000  
Mbps speed, but then be unable to achieve link.  
The downshift feature enables the 82540EP/EM PHY to auto-negotiate with another gigabit link  
partner using a two or three pair cable and downshift to link at 100 Mbps or 10 Mbps, whichever is  
the highest speed below gigabit that the link partner is capable of.  
By default, downshift is turned on. Refer to Table 13-39 to disable the downshift feature.  
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11.3  
Cable Length Detection (copper only)  
In 100/1000 Mbps operation, the Ethernet controller PHY attempts to indicate the approximate  
length of the CAT 5 cable attached. The estimated cable length is reported as one of the following  
ranges:  
• <= 50 m  
• 50 – 80 m  
• 80 – 110 m  
• 110 – 140 m  
• >= 140 m  
The estimated cable length can be obtained by reading the PHY Specific Status Register bits 9:7.  
11.4  
PHY Power Management (copper only)  
The Ethernet controller PHY supports power-management based on either link status, MAC  
power-state, or both. During link-down states, the PHY utilizes its energy-detection capabilities to  
consume the least amount of power while still being capable of resuming link-up automatically. the  
Ethernet controller can be configured to automatically reduce PHY power during certain MAC D3  
states by re-negotiating a low-speed link (the default behavior, but this can be disabled).  
11.4.1  
Link Down – Energy Detect (copper only)  
When the link is operational and the Ethernet controller PHY detects loss of link, it initiates an  
Auto-Negotiation session. Failing to re-establish link via auto-negotiation, the PHY reverts to an  
Energy Detect power-down state. Following link loss, the PHY monitors receive energy on the  
wire. If the PHY detects energy on the wire, it starts to initiate Auto-Negotiation sending FLPs for  
five seconds. If at the end of five seconds the Auto-Negotiation has not completed, then the PHY  
stops sending FLPs and returns to monitoring receive energy. While monitoring receive energy, the  
PHY sends out a single 10 Mbps NLP (Normal Link Pulse) every one second in an attempt to wake  
up a connected device.  
The above behavior is considered to be an advanced Energy-Detect (Energy Detect+) mode of  
PHY operation. The PHY can also be configured for a regular Energy Detect mode, which behaves  
similarly, except does not send out NLPs while monitoring receive energy. In this configuration,  
the Ethernet controller PHY can be woken by a connected device, but does not wake up the  
connected device itself.  
The PHY Specific Control Register bits 9 and 8 described in Section 13.4.7.1.13 are used to  
configure the specific Energy-Detect mode of behavior for the PHY.  
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11.4.2  
11.4.3  
11.4.4  
D3 State, No Link Required (copper only)  
Each time the MAC transitions to a D3 or D0u power-state with no link required (wakeup disabled  
and no manageability enabled), the PHY enters its IEEE power-down mode, consuming the least  
amount of power possible. When powered-down, the PHY does not perform any form of Energy  
Detection, and does not generate any energy (NLPs) on the wire itself.  
MAC transitions back to D0 power-states, either through explicit system/software mechanisms or  
by hardware reset operations, return the PHY back to a functional power-state. This will also re-  
initiate an auto-negotiation attempt advertising all speeds possible (10/100/1000 Mbps) , reverting  
1
to an Energy Detect state if unsuccessful in establishing link-up.  
D3 Link-Up, Speed-Management Enabled (copper only)  
If the MAC is configured for PHY power management (CTRL.EN_PHY_PWR_MGMT = 1b) and  
the PHY is linked at 1000 Mbps, then upon MAC transitions to D3 or D0u power-states where link  
IS required (either wakeup or manageability are enabled), the PHY re-initiates an Auto-  
Negotiation operation, advertising only 10/100 Mbps capability. This results in D3 operation at a  
lower-speed link and a reduced power level.  
If a wakeup, management operation, or other system event causes the MAC to revert to fully-  
operational D0 state, the PHY initiates another Auto-Negotiation operation, advertising all 10/100/  
1000 Mbps speed capability, in order to return to maximum-speed operation.  
D3 Link-Up, Speed-Management Disabled (copper only)  
If the MAC is configured for no PHY power management (CTRL.EN_PHY_PWR_MGMT = 0b),  
and the MAC transitions to D3 power-states where link is required for either wakeup or  
manageability, then the PHY simply remains operational at its current line speed, without initiating  
a new Auto-Negotiation operation. This configuration is not recommended, since D3 power  
consumption at 1000 Mbps exceeds 20 mA Vaux.  
1. Half duplex not supported.  
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11.5  
Initialization  
Note: Section 11.5 through Section 11.14 apply only to the 82541xx and 82547GI/EI Ethernet  
controllers.  
At power-up or reset, the PHY core performs the initialization as shown in Figure 11-1. The  
software driver has access to the PHY register 0d, bits 15 and 11 for PHY reset and PHY Power  
Down control, respectively.  
Power-up  
or  
Reset  
Read H/W  
Control  
Interface  
Initialize  
MDIO  
Registers  
Pass control  
to  
MDIO Interface  
Figure 11-1. PHY Initialization Sequence  
11.5.1  
MDIO Control Mode  
In the MDIO Control mode, the PHY uses the Hardware Control Interface to set up initial (default)  
values of the MDIO registers. Once initial values are set, bit control reverts to the MDIO interface.  
The PHY can perform some low level initializations such as DSP configuration based upon  
EEPROM settings. The details of those initializations are reserved.  
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11.6  
Determining Link State  
The PHY and its link partner determine the type of link established through one of three methods:  
• Auto-Negotiation  
• Parallel Detection  
• Forced Operation  
Auto-Negotiation is the only method allowed by the 802.3ab standard for establishing a  
1000BASE-T link, although forced operation could be used for test purposes. For 10/100 links, any  
of the three methods can be used. The sections that follow discuss each in greater detail.  
Figure 11-2 provides an overview of link establishment. First the PHY checks if Auto-Negotiation  
is enabled. By default, the PHY supports Auto-Negotiation (PHY register 0, bit 12). If not, the  
PHY forces operation as directed. If Auto-Negotiation is enabled, the PHY begins transmitting  
Fast Link Pulses (FLPs) and receiving FLPs from its link partner. If FLPs are received by the PHY,  
Auto-Negotiation proceeds. It also can receive 100BASE-TX MLT3 and 10BASE-T Normal Link  
Pulses (NLPs). If either MLT3 or NLPs are received, it aborts FLP transmission and immediately  
brings up the corresponding half-duplex link.  
Power-Up, Reset,  
Link Failure  
Start  
Yes  
A/N  
Enabled  
?
Send FLP  
No  
Speed  
0 = 10M  
0.13  
?
1 = 100M  
Yes  
No  
Detect  
FLP  
Send IDLES  
Send NLP  
Auto  
Negotiate  
Parallel  
Detect  
100M  
Half-Duplex  
Link  
Detect  
10Mbps  
?
Detect  
10Mbps  
?
Detect  
IDLES  
Yes  
No  
No  
Yes  
Yes  
No  
Take  
Link  
Down  
Take  
Link  
Up  
Link  
Down  
Link  
Up  
10M  
Half-Duplex  
Link  
Detect  
NLP  
Yes  
Figure 11-2. Overview of Link Establishment  
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11.6.1  
False Link  
When the PHY is first powered on, reset, or encounters a link down state, it must determine the line  
speed and operating conditions to use for the network link.  
The PHY first checks the MDIO registers (initialized via the Hardware Control Interface or written  
by software) for operating instructions. Using these mechanisms, programmers can command the  
PHY to do one of the following:  
• Force twisted-pair link operation to:  
— 1000T Full Duplex  
— 1000T Half Duplex  
— 100TX, Full Duplex  
— 100TX, Half Duplex  
— 10BASE-T, Full Duplex  
— 10BASET, Half Duplex  
• Allow Auto-Negotiation/parallel-detection.  
In the first six cases (forced operation), the PHY immediately begins operating the network  
interface as commanded. In the last case, the PHY begins the Auto-Negotiation/parallel-detection  
process.  
11.6.2  
Forced Operation  
Forced operation can be used to establish 10 and 100 links, and 1000 links for test purposes. In this  
method, Auto-Negotiation is disabled completely and the link state of the PHY is determined by  
PHY register 0d.  
Note: When speed is forced, the MDI/MDI-X crossover feature is not functional.  
In forced operation, the programmer sets the link speed (10, 100, or 1000) and duplex state (full or  
half). For Gigabit (1000) links, the programmer must explicitly designate one side as the Master  
and the other as the Slave. Table 10-1 summarizes link establishment procedures.  
Table 10-1. Determining Duplex State Via Parallel Detection  
Configuration  
Both sides set for Auto-Negotiate.  
Both sides set for forced operation.  
Result  
Link is established via Auto-Negotiation.  
No problem as long as duplex settings match.  
One side set for Auto-Negotiation and the other for  
forced, half-duplex.  
Link is established via parallel detect.  
Link is established; however, sides disagree, resulting  
in transmission problems. Forced side is full-duplex,  
Auto-Negotiation side is half-duplex.  
One side set for Auto-Negotiation and the other for  
forced full-duplex.  
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11.6.3  
11.6.4  
Auto Negotiation  
The PHY supports the IEEE 802.3u Auto-Negotiation scheme with next page capability. Next Page  
exchange uses PHY register 7d to send information and PHY register 8d to receive them. Next  
Page exchange can only occur if both ends of the link advertise their ability to exchange Next  
Pages.  
Parallel Detection  
Parallel detection can only be used to establish 10 and 100 links. It occurs when the PHY tries to  
negotiate (transmit FLPs to its link partner), but instead of sensing FLPs from the link partner, it  
senses 100BASE-TX MLT3 code or 10BASE-T Normal Link Pulses (NLPs) instead. In this case,  
the PHY immediately stops Auto-Negotiation (terminates transmission of FLPs) and immediately  
brings up whatever link corresponds to what it has sensed (MLT3 or NLPs). If the PHY senses both  
of the technologies together, a parallel detection fault is detected and the PHY continues sending  
FLPs  
With parallel detection, it is impossible to determine the true duplex state of the link partner, and  
the IEEE standard requires the PHY to assume a half-duplex link. Parallel detection also does not  
allow exchange of flow-control ability (PAUSE and ASM_DIR) or Master/Slave relationship  
required by 1000BASE-T. For this reason, parallel detection cannot be used to establish Gigabit  
Ethernet links.  
11.7  
Link Criteria  
Once the link state is determined—via Auto-Negotiation, parallel detection or forced operation—  
the PHY and its link partner bring up the link.  
11.7.1  
1000BASE-T  
For 1000BASE-T links, the PHY and its link partner enter a training phase. They exchange idle  
symbols and use the information gained to set their adaptive filter coefficients.  
Either side indicates completion of the training phase to its link partner by changing the encoding  
of the idle symbols it transmits. When both sides so indicate, the link is up. Each side continues  
sending idle symbols whenever it has no data to transmit. The link is maintained as long as valid  
idle, data, or carrier extension symbols are received.  
11.7.2  
100BASE-TX  
For 100BASE-TX links, the PHY and its link partner immediately begin transmitting idle symbols.  
Each side continues sending idle symbols whenever it has no data to transmit. The link is  
maintained as long as valid idle symbols or data is received.  
In 100Mbps mode, the PHY establishes a link whenever the scrambler becomes locked and  
remains locked. Link will remain up unless the descrambler receives idles at less than a specified  
rate.  
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11.7.3  
10BASE-T  
For 10BASE-T links, the PHY and its link partner begin exchanging Normal Link Pulses (NLPs).  
The PHY transmits an NLP every 16 ms, and expects to receive one every 10 to 20 ms. The link is  
maintained as long as normal link pulses are received.  
11.8  
Link Enhancements  
The PHY offers two enhanced link functions, each of which are discussed in the sections that  
follow:  
• SmartSpeed  
• Flow Control  
11.8.1  
SmartSpeed  
SmartSpeed is an enhancement to Auto-Negotiation that enables the PHY to react intelligently to  
network conditions that prohibit establishment of a 1000BASE-T link, such as cable problems.  
Such problems might enable Auto-Negotiation to complete, but then inhibit completion of the  
training phase. Normally, if a 1000BASE-T link fails, the PHY returns to the Auto-Negotiation  
state with the same speed settings indefinitely. With SmartSpeed enabled, after five failed attempts,  
the PHY automatically downgrades the highest ability it advertises to the next lower speed: from  
1000 to 100 to 10. Once a link is established, and if it is later broken, the PHY automatically  
upgrades the capabilities advertised to the original setting.  
11.8.1.1  
Using SmartSpeed  
SmartSpeed is enabled by setting PHY register 16d, bit 7 to 1b. When SmartSpeed downgrades the  
PHY advertised capabilities, it sets bit 5 of PHY register 19. When link is established, its speed is  
indicated in PHY register 17, bits 15:14. SmartSpeed automatically resets the highest-level Auto-  
Negotiation abilities advertised, if link is established and then lost for more than two seconds.  
11.8.2  
Flow Control  
Flow control enables congested nodes to pause traffic. MACs indicate their ability to implement  
flow control during Auto-Negotiation.  
The PHY transparently supports MAC-to-MAC advertisement of flow control through its Auto-  
Negotiation process. Prior to Auto-Negotiation, the MAC indicates its flow control capabilities via  
PHY register 4d, bit 10 (Pause) and PHY register 4d, bit 11 (ASM_DIR). After Auto-Negotiation,  
the link partner’s flow control capabilities are indicated in PHY register 5d, bits 11:10.  
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Table 10-2 lists the intended operation for the various settings of ASM_DIR and Pause. This  
information is provided for reference only; it is the responsibility of the MAC to implement the  
correct function. The PHY merely enables the two MACs to communicate their abilities to each  
other.  
Table 10-2. Pause And Asymmetric Pause Settings  
ASM_DIR Settings  
Pause Setting -  
Local (PHY  
Register 4d, Bit  
9)  
Pause Setting -  
Remote (PHY  
Register 5d, Bit  
9)  
Local  
(PHY Register 4d, Bit  
10) and Remote (PHY  
Register 5d, Bit 10)  
Result  
Symmetric - Either side can flow control  
the other  
1b  
1b  
Asymmetric - Remote can flow control  
local only  
1b  
0b  
1b  
0b  
1b  
Both ASM_DIR = 1b  
Asymmetric - Local can flow control  
remote  
0b  
0b  
No flow control  
Symmetric - Either side can flow control  
the other  
1b  
Either or both  
ASM_DIR = 0b  
Either or both = 0b  
No flow control  
11.9  
Management Data Interface  
The PHY supports the IEEE 802.3 MII Management Interface also known as the Management  
Data Input/Output (MDIO) Interface. The MDIO interface consists of a physical connection to the  
MAC, a specific protocol which runs across the connection, and a 16-bit MDIO register set.  
PHY Registers 0d through 10d and 15d are required and their functions are specified by the IEEE  
802.3 specification. Additional registers are included for expanded functionality.  
11.10  
Low Power Operation  
The Ethernet controller can be get into a low-power state according to MAC control (Power  
Management controls) or via PHY register 0d. In either power down mode, the Ethernet controller  
is not capable of receiving or transmitting packets.  
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11.10.1 Powerdown via the PHY Register  
The PHY can be powered down using the control bit found in PHY register 0d, bit 11. This bit  
powers down a significant portion of the port but clocks to the register section remain active. This  
enables the PHY management interface to remain active during power-down. The power-down bit  
is active high. When the PHY exits software power-down (PHY register 0d, bit 11 = 1b), it re-  
initializes all analog functions, but retains its previous configuration settings.  
11.10.2 Smart Power-Down  
Smart Power-Down (SPD) is a link-disconnect capability applicable to all power management  
states, and is intended for mobile applications. Smart powerdown combines a power saving  
mechanism with the fact that link might disappear and resume.  
SPD is enabled by PHY register 20d, bit 5 or by the SPD Enable bit in the EEPROM, and is  
entered when the PHY detects link lost. Auto-Negotiation must also be enabled. While in the SPD  
state, the PHY powers down circuits and clocks that are not required for detection of link activity.  
The PHY is still able to detect link pulses (including parallel detect) and wake up to engage in link  
negotiation. The PHY does not send link pulses (NLP) while in the SPD state. Register accesses  
are still possible.  
Connecting a member of the family to another system with the SPD feature can lead to link failures  
if both ports are allowed to enter the SPD state.  
11.11  
1000 Mbps Operation  
11.11.1 Introduction  
This section provides an overview of 1000BASE-T functions, followed by discussion and review  
of the internal functional blocks shown in Figure 11-3.  
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MAC Interface  
8
8
Side-stream  
Scrambler /  
Descrambler  
Trellis Viterbi  
Encoder/ Decoder  
4
DSP  
4
ECHO, NEXT,  
FEXT Cancellers  
4DPAM5  
Encoder  
AGC, A/D,  
Timing Recovery  
Pulse Shaper,  
DAC, Filter  
Hybrid  
Line Driver  
Line  
Interface  
Figure 11-3. 1000 Base-T PHY Functions Overview  
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11.11.2 Transmit Functions  
This section describes functions used when the Media Access Controller (MAC) transmits data  
through the PHY and out onto the twisted-pair connection.  
11.11.2.1 Scrambler  
The scrambler randomizes the transmitted data. The purpose of scrambling is two fold:  
1. Scrambling eliminates repeating data patterns from the 4DPAM5 waveform to reduce EMI.  
2. Each channel (A, B, C, D) gets a unique signature that the receiver uses for identification.  
The scrambler is driven by a Linear Feedback Shift Register (LFSR), which is randomly loaded at  
power-up. The LFSR function used by the Master differs from that used by the Slave, giving each  
direction its own unique signature. The LFSR, in turn, generates uncorrelated outputs. These  
outputs randomize the inputs to the 4DPAM5 and Trellis encoders and randomize the sign of the  
4DPAM5 outputs.  
11.11.3 Transmit FIFO  
The transmit FIFO re-synchronizes data transmitted by the MAC to the transmit reference used by  
the PHY.  
11.11.3.1 Transmit Phase-Locked Loop PLL  
This function generates the 125 MHz timing reference used by the PHY to transmit 4DPAM5  
symbols. When the PHY is the Master side of the link, the crystal input is the reference for the  
transmit PLL. When the PHY is the Slave side of the link, the recovered receive clock is the  
reference for the transmit PLL.  
11.11.3.2 Trellis Encoder  
The Trellis Encoder uses the two high-order bits of data and its previous output to generate a ninth  
bit, which determines if the next 4DPAM5 pattern should be even or odd. This function provides  
forward error correction and enhances the signal-to-noise (SNR) ratio by a factor of 6 dB.  
11.11.3.3 4DPAM5 Encoder  
The 4DPAM5 encoder translates 8B codes transmitted by the MAC into 4DPAM5 symbols. The  
encoder operates at 125 Mhz, which is both the frequency of the MAC interface and the baud rate  
used by 1000BASE-T.  
Each 8B code represents one of 256 data patterns. Each 4DPAM5 symbol consists of one of five  
4
signal levels (-2,-1,0,1,2) on each of the four twisted pair (A,B,C,D) representing 5 or 625  
possible patterns per baud period. Of these, 113 patterns are reserved for control codes, leaving 512  
patterns for data. These data patterns are divided into two groups of 256 even and 256 odd data  
patterns. As a result, each 8B octet has two possible 4DPAM5 representations—one even and one  
odd pattern.  
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11.11.3.4 Spectral Shaper  
This function causes the 4DPAM5 waveform to have a spectral signature that is very close to that  
of the MLT3 waveform used by 100BASE-TX. This enables 1000BASE-T to take advantage of  
infrastructure (cables, magnetics) designed for 100BASE-TX.  
The shaper works by transmitting 75% of a 4DPAM5 code in the current baud period, and adding  
the remaining 25% into the next baud period.  
11.11.3.5 Low-Pass Filter  
To aid with EMI, this filter attenuates signal components more than 180 Mhz. In 1000BASE-T, the  
fundamental symbol rate is 125 Mhz.  
11.11.3.6 Line Driver  
The line driver drives the 4DPAM5 waveforms onto the four twisted-pair channels (A, B, C, D),  
adding them onto the waveforms that are simultaneously being received from the link partner.  
11.11.3.7 Transmit/Receive Flow  
D0  
D1  
D2  
D3  
D4  
D5  
D6  
D7  
PAM-5  
Encoded Output  
to 4-Pair UPT Line  
8
9
Trellis  
Encoder  
4D  
PAM-5  
Scrambler  
Scrambler Polynomials:  
13  
33  
1 + x + x (Master PHY Mode)  
20  
33  
1 + x + x (Slave PHY Mode)  
Figure 11-4. 1000BASE-T Transmit Flow And Line Coding Scheme  
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D0  
D1  
D2  
D3  
D4  
D5  
D6  
D7  
Polynomial  
8 bits  
8 bits  
Descrambler  
DSP  
Receiver  
PAM-5  
Encoded Input  
from 4-Pair UTP Line  
GMII  
Figure 11-5. 1000BASE-T Receive Flow  
11.11.4 Receive Functions  
This section describes function blocks that are used when the PHY receives data from the twisted  
pair interface and passes it back to the MAC.  
11.11.4.1 Hybrid  
The hybrid subtracts the transmitted signal from the input signal, allowing the use of simple  
100BASE-TX compatible magnetics.  
11.11.4.2 Automatic Gain Control  
The Automatic Gain Control (AGC) normalizes the amplitude of the received signal, adjusting for  
the attenuation produced by the cable.  
11.11.4.3 Timing Recovery  
This function re-generates a receive clock from the incoming data stream which is used to sample  
the data. On the Slave side of the link, this clock is also used to drive the transmitter.  
11.11.4.4 Analog-to-Digital Converter  
The Analog-to-Digital (ADC) function converts the incoming data stream from an analog  
waveform to digitized samples for processing by the DSP core.  
11.11.4.5 Digital Signal Processor  
The Digital Signal Processor (DSP) provides per-channel adaptive filtering, which eliminates  
various signal impairments including:  
• Inter-symbol interference (equalization).  
• Echo caused by impedance mismatch of the cable.  
• Near-end crosstalk (NEXT) between adjacent channels (A, B, C, D).  
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• Far-end crosstalk (FEXT)  
• Propagation delay variations between channels of up to 120 ns.  
• Extraneous tones that have been coupled into the receive path.  
The adaptive filter coefficients are initially set during the training phase. They are continuously  
adjusted (adaptive equalization) during operation through the decision-feedback loop.  
11.11.4.6 Descrambler  
The descrambler identifies each channel by its characteristic signature, removing the signature and  
re-routing the channel internally. In this way, the receiver can correct for channel swaps and  
polarity reversals. The descrambler uses the same base LFSR used by the transmitter on the other  
side of the link.  
The descrambler requires approximately 15 s. to lock, normally accomplished during the training  
phase.  
11.11.4.7 Viterbi Decoder/Decision Feedback Equalizer (DFE)  
The Viterbi decoder generates clean 4DPAM5 symbols from the output of the DSP. The decoder  
includes a Trellis encoder identical to the one used by the transmitter. The Viterbi decoder simulta-  
neously looks at the received data over several baud periods. For each baud period, it predicts  
whether the symbol received should be even or odd, and compares that to the actual symbol  
received. The 4DPAM5 code is organized in such a way that a single level error on any channel  
changes an even code to an odd one and vice versa. In this way, the Viterbi decoder can detect  
single-level coding errors, effectively improving the Signal-To-Noise (SNR). When an error  
occurs, this information is quickly fed back into the equalizer to prevent future errors.  
11.11.4.8 4DPAM5 Decoder  
The 4DPAM5 decoder generates 8B data from the output of the Viterbi decoder.  
11.12  
11.13  
100 Mbps Operation  
The MAC passes data to the PHY over the MII. The PHY encodes and scrambles the data, then  
transmits it using MLT-3 for 100TX over copper. The PHY descrambles and decodes MLT-3 data  
received from the network. When the MAC is not actively transmitting data, the PHY sends out  
idle symbols on the line.  
10 Mbps Operation  
The PHY operates as a standard 10 Mbps transceiver. Data transmitted by the MAC as 4-bit nibbles  
is serialized, Manchester-encoded, and transmitted on the MDI[0]+/- outputs. Received data is  
decoded, de-serialized into 4-bit nibbles and passed to the MAC across the internal MII. The PHY  
supports all the standard 10 Mbps functions.  
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11.13.1 Link Test  
In 10 Mbps mode, the PHY always transmits link pulses. If the Link Test Function is enabled, it  
monitors the connection for link pulses. Once it detects 2 to 7 link pulses, data transmission is  
enabled and remains enabled as long as the link pulses or data reception continues. If the link  
pulses stop, the data transmission is disabled.  
If the Link Test function is disabled, the PHY might transmit packets regardless of detected link  
pulses. Setting PHY register 16d, bit 14 can disable the Link Test function.  
11.13.2 10Base-T Link Failure Criteria and Override  
Link failure occurs if Link Test is enabled and link pulses stop being received. If this condition  
occurs, the PHY returns to the Auto-Negotiation phase if Auto-Negotiation is enabled. Setting  
PHY register 16d, bit 14 disables the Link Integrity Test function, then the PHY transmits packets,  
regardless of link status.  
11.13.3 Jabber  
If the MAC begins a transmission that exceeds the jabber timer, the PHY disables the Transmit and  
loopback functions and asserts collision indication to the MAC. The PHY automatically exits  
jabber mode after 250-750 ms. This function can be disabled by setting PHY register 16d, bit 10 to  
1b.  
11.13.4 Polarity Correction  
The PHY automatically detects and corrects for the condition where the receive signal  
(MDI_PLUS[0]/MDI_MINUS[0]) is inverted. Reversed polarity is detected if eight inverted link  
pulses, or four inverted end-of-frame markers, are received consecutively. If link pulses or data are  
not received for 96-130 ms, the polarity state is reset to a non-inverted state.  
11.13.5 Dribble Bits  
The PHY device handles dribble bits for all of its modes. If between one to four dribble bits are  
received, the nibble is passed across the interface. The data passed across is padded with 1b’s if  
necessary. If between five to seven dribble bits are received, the second nibble is not sent onto the  
internal MII bus to the MAC. This ensures that dribble bits between 1-7 do not cause the MAC to  
discard the frame due to a CRC error.  
11.14  
PHY Line Length Indication  
The PHY has a mechanism to deliver coefficient data for use in measuring cable length. If this  
capability is required, please contact your Intel representative for details.  
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12  
1
12.1  
Introduction  
The 82546GB/EB architecture includes two instances of both the MAC and PHY (see Figure 2-1).  
With both MAC/PHY pairs operating, the Ethernet controller appears as a multi-function PCI  
device containing two identically-functioning devices. To avoid confusion, each MAC (when  
combined with either an internal PHY or an internal TBI transceiver/SerDes) is referred to as  
“LANx”, where x = “A” or x = “B” to refer to each logical LAN device (LAN A or LAN B).  
This section details specific features common to each MAC or PHY, resources/interfaces for which  
dedicated independent hardware/software interfaces exists for each LAN, as well as resources  
which are shared by both LAN devices.  
The Ethernet controller normally appears to the system as a single, multi-function PCI device. It  
provides the ability to selectively disable one of the internal LAN functions, thereby allowing it to  
appear to the system as a single-function, single-LAN device. The mechanisms for controlling this  
behavior and the resulting appearance to the system are described in Section 12.5 entitled, “LAN  
Disable”.  
12.2  
Features of Each MAC  
The Ethernet controller is designed to have the capability to appear as two independent instances of  
a gigabit controller. The following section details major features that can be considered to be  
distinct features available to each Ethernet controller MAC independently.  
12.2.1  
PCI/PCI-X interface  
The Ethernet controller contains a single physical PCI/PCI-X interface. The Ethernet controller is  
designed so that each of the logical LAN devices (LAN A and LAN B) appear as a distinct PCI/  
PCI-X bus device implementing, along with other registers, the following PCI device header space:  
Byte Offset  
Byte 0  
Byte 1  
Byte 2  
Byte 3  
0h  
4h  
Device ID  
Vendor ID  
Command Register  
Revision ID 00h  
Latency Timer Cache Line Size  
Status Register  
8h  
Class Code 020000h  
Header Type 00h  
Ch  
BIST 00h  
10h  
14h  
1h8  
1Ch  
20h  
Base Address 0  
Base Address 1  
Base Address 2  
Base Address 3  
Base Address 4  
1. Section 12 only applies to the 82546GB/EB.  
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Byte Offset  
Byte 0  
Byte 1  
Byte 2  
Byte 3  
24h  
28h  
2Ch  
30h  
34h  
38h  
Base Address 5  
Cardbus CIS Pointer (not used)  
Subsystem Vendor ID  
Subsystem ID  
Expansion ROM Base Address  
Reserved  
Cap_Ptr  
Reserved  
Interrupt Line  
00h  
Min_Grant  
FFh  
Interrupt Pin  
01h or 00h)  
3Ch  
Max_Latency 00h  
Many of the fields of the PCI header space contain hardware default values that are either fixed or  
can be overridden using EEPROM, but cannot be independently specified for each logical LAN  
device. The following fields are considered to be common to both LAN devices:  
The Vendor ID of the Ethernet controller can be specified via EEPROM, but  
Vendor ID  
Revision  
only a single value can be specified. The value is reflected identically for both  
LAN devices.  
The revision number of the Ethernet controller is reflected identically for both  
LAN devices.  
This field indicates if a device is single function or multifunction. The value  
reflected in this field is reflected identically for both LAN devices, but the actual  
value reflected depends on LAN Disable configuration.  
When both Ethernet controller LAN ports are enabled, both PCI headers return  
80h in this field, acknowledging being part of a multi-function device. LAN A  
exists as device “function 0”, while LAN B exists as device “function 1”.  
Header Type  
If one of the LAN ports is disabled, then only a single-function device is  
indicated (this field returns a value of 00h), and the LAN exists as device  
“function 0”.  
The Subsystem ID of the Ethernet controller can be specified via EEPROM,  
but only a single value can be specified. The value is reflected identically for  
both LAN devices.  
Subsystem ID  
The Subsystem Vendor ID of the Ethernet controller can be specified via  
EEPROM, but only a single value can be specified. The value is reflected  
identically for both LAN devices.  
Subsystem Vendor ID  
Class Code,  
Cap_Ptr,  
Max Latency,  
Min Grant  
These fields reflect fixed values that are constant values reflected for both LAN  
devices.  
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The following fields are implemented unique to each LAN device:  
The Device ID reflected for each LAN device can be independently specified  
via EEPROM.  
Device ID  
Command,  
Status  
Each LAN device implements its own command/status registers.  
Each LAN device implements these registers uniquely. The system should  
program these fields identically for each LAN to ensure consistent behavior  
and performance of each device.  
Latency Timer,  
Cache Line Size  
Memory BAR,  
Flash BAR,  
Each LAN device implements its own Base Address registers, allowing each  
device to claim its own address region(s).  
IO BAR,  
Expansion ROM BAR  
Each LAN device independently indicates which interrupt pin (INTA# or INTB#)  
is used by that Ethernet controller’s MAC to signal system interrupts. The  
value for each LAN device can be independently specified via EEPROM, but  
only if both LAN devices are enabled.  
Interrupt Pin  
12.2.2  
MAC Configuration Register Space  
All device control/status registers detailed in Section 13.4, Main Register Descriptions, are  
implemented per-LAN device. Each LAN device can be accessed using memory or I/O cycles,  
depending on the specific BAR setting(s) established for that LAN device.  
Register accesses to each MAC instance are independent. In PCI bus operation, a register access to  
one LAN which is retried as a delayed-read requires subsequent accesses to that LAN to retry the  
read identically until complete. An outstanding delayed-read for one LAN device does not impact  
the Ethernet controller’s ability to accept a register access to the other LAN. Similarly, in PCI-X  
bus operation, and register access resulting in a split & split-completion by one LAN device in no  
way prevents the other LAN device from accepting and servicing (or splitting) an access to its  
register space.  
12.2.3  
SDP, LED, INT# output  
Each LAN device provides an independent set of LED outputs and software-programmable I/O  
pins (SDP). Four LED outputs and four SDP pins are provided per LAN device. These pins and  
their function are bound to a specific LAN device (eight SDP pins cannot be associated with a  
single LAN device, for example).  
Each LAN device can use a dedicated pin for signalling interrupts to the system. Two pins, INTA#  
and INTB#, exist on the Ethernet controller to signal interrupts by the different LAN devices. The  
specific pin used by each LAN is configurable when both LAN devices are enabled.  
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12.3  
Shared EEPROM  
The Ethernet controller uses a single EEPROM device to configure hardware default parameters  
for both LAN devices, including Ethernet Individual Addresses (IA), LED behaviors, receive  
packet-filters for manageability and wakeup capability, etc. Certain EEPROM words are used to  
specify hardware parameters which are LAN device-independent (such as those that affect circuits  
behavior). Other EEPROM words are associated with a specific LAN device. LAN A and LAN B  
accesses the EEPROM to obtain their respective configuration settings.  
12.3.1  
EEPROM Map  
The EEPROM map identifies those words configuring both LAN devices or the entire Ethernet  
controller component as “LAN A/B Shared”. Those words configuring a specific LAN device  
parameters are identified as either “LAN A” or “LAN B”.  
The following EEPROM words warrant additional notes specifically related to dual-LAN support:  
The EEPROM specifies the IA associated with the LAN A device and used as  
the hardware default of the Receive Address Registers for that device. The  
hardware-default IA for the LAN B device is automatically determined by the  
same EEPROM word, and is set to the value of {Ethernet IA LAN A with its  
Ethernet Address (IA)  
(LAN A/B shared)  
least significant bit inverted}.  
These EEPROM words specify hardware-default values for parameters that  
apply a single value to both LAN devices, such as link configuration  
parameters required for auto-negotiation, wakeup settings, PCI/PCI-X bus  
advertised capabilities, etc.  
Initialization Control 1,  
Initialization Control 2  
(LAN A/B shared)  
This EEPROM word configures default values associated with each LAN  
device’s hardware connections, including which link mode (internal PHY,  
external TBI SerDes) is used with this LAN device. Because a separate  
EEPROM word configures the defaults for each LAN, extra care must be taken  
to ensure that the EEPROM image does not specify a resource conflict. For  
example, multiple LAN devices both attempting to utilize the external TBI  
transceiver interface at once.  
Initialization Control 3  
(LAN A, LAN B unique)  
This EEPROM word configures manageability parameters. Note that this word  
controls whether an internal ASF controller is enabled/disabled for this LAN,  
and whether the SMBus is enabled/disabled for this LAN. Extra care must be  
taken to ensure that the EEPROM image does not specify a resource conflict –  
if an internal ASF controller is being used, it can only be enabled for a single  
LAN device. The SMBus can only be enabled for a single LAN device.  
Management Control  
12.3.2  
EEPROM Arbitration  
The Ethernet controller uses a single EEPROM to store hardware configuration words for both  
LAN devices. The words used by each specific LAN device are noted in the EEPROM map. Each  
LAN device obtains its EEPROM configuration parameters by performing its own independent  
EEPROM read. Each LAN device reads the entire EEPROM image, verifying the EEPROM  
signature, and applying the word(s) appropriate for the specific LAN device. The Ethernet  
controller internally arbitrates between EEPROM access by the two LAN devices, to ensure that  
each device is able to perform a complete, uninterrupted EEPROM read sequence.  
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The result of multiple LAN devices’ reading EEPROM is that power-on and reset-initiated  
EEPROM read sequences might appear slightly differently from the sequences illustrated during  
the discussion of power-state transitions (Section 6.3.2). Those illustrations indicate EEPROM  
read periods without distinguishing between reads by LAN A versus LAN B devices. At initial  
power-on, both LAN devices always execute an EEPROM read sequence. However, since the  
enabling/disabling of a particular LAN device occurs on the deassertion of PCI reset, the post-reset  
EEPROM read sequence(s) are only performed by LAN device(s) that are enabled. The following  
illustration more clearly illustrates the EEPROM read sequence for a scenario where a single LAN  
device is enabled:  
Power  
t
ppg  
1
LAN_PWR_GOOD  
125 MHz XTAL IN  
t
txpg  
CLK  
t
pgrst  
6
t
clkpr  
5
t
pgee  
RST#  
t
tee  
pree  
3
tee  
2
3
EEPROM read,  
LAN B device  
EEPROM read,  
LAN A device  
EEPROM read,  
LAN A device  
Reading EEPROM  
PCI Pins  
t
eepci  
9
Running  
12.4  
Shared FLASH  
The Ethernet controller provides an interface to an external FLASH/ROM memory device, as  
described in Section 7. This FLASH/ROM device can be mapped into memory and/or I/O address  
space for each LAN device through the use of PCI Base Address Registers (BARs). Bit 3 of the  
EEPROM Initialization Control Word 3 associated with each LAN device selectively disables/  
enables whether the FLASH can be mapped for each LAN device by controlling the BAR register  
advertisement and writeability.  
12.4.1  
FLASH Access Contention  
Unlike the shared EEPROM implementation, the Ethernet controller does NOT implement any  
internal arbitration between FLASH accesses initiated through the LAN A device and those  
initiated through the LAN B device. If accesses from both LAN devices are initiated during the  
same approximate time window, access contention can occur. If contention occurs, the external  
FLASH addresses can be corrupted or unstable throughout the access. During writes to FLASH,  
contention can result in corrupt or unstable data values; contention during reads can result in  
erroneous read data being returned.  
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Note: Access contention to FLASH by both LAN devices is more than likely to result in indeterminate  
data results (during read transactions), corrupted FLASH (during write transactions), or other  
unpredictable behavior.  
To avoid this contention, accesses from both LAN devices MUST be synchronized using external  
software synchronization of the memory or I/O transactions responsible for the access. It might be  
possible to ensure contention-avoidance simply by nature of software sequentially.  
12.5  
LAN Disable  
For a LOM design, it might be desirable for the system to provide BIOS-setup capability for  
selectively enabling or disabling LOM devices. This might allow an end-user more control over  
system resource-management, avoid conflicts with add-in NIC solutions, etc. The Ethernet  
controller provides support for selectively enabling or disabling one or both LAN device(s) in the  
system.  
12.5.1  
Overview  
Device presence (or non-presence) must be established early during BIOS execution in order to  
ensure that BIOS resource-allocation (of interrupts, of memory or IO regions) is done according to  
devices that are present only. This is frequently accomplished using a BIOS CVDR (Configuration  
Values Driven on Reset) mechanism. The Ethernet controller LAN-disable mechanism is  
implemented in order to be compatible with such a solution. The Ethernet controller samples two  
pins (FLASH data pins, bits 1 and 0) on reset to determine the LAN-enable configuration.  
When a particular LAN is disabled, all internal clocks to that LAN are disabled, the device is held  
in reset, and the internal PHY for that LAN is powered-down. The device does not respond to PCI  
configuration cycles. Effectively, the LAN device becomes invisible to the system from both a  
configuration and power-consumption standpoint.  
Note: Since the LAN-disable mechanisms is implemented using the FLASH data pins, this mechanism  
can only be used when no FLASH device is present (FLASH disabled). An Ethernet controller-  
based NIC built with support for a FLASH device always enables both LAN devices.  
12.5.2  
Values Sampled on Reset  
The Ethernet controller samples values from the pins FLSH_DATA[1] and FLSH_DATA[0] on the  
rising edge of LAN_PWR_GOOD and RST#. Based on the values sampled, the LAN devices are  
enabled/disabled according to the following table:  
Pin sampled  
LAN device controlled  
Enable/Disable  
Vcc/logic 1b = enabled  
Vss/logic 0b = disabled  
FLSH_DATA[0]  
FLSH_DATA[1]  
LAN A device  
LAN B device  
???  
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12.5.3  
12.5.4  
Multi-Function Advertisement  
If one of the LAN devices is disabled, the Ethernet controller no longer is a multi-function device.  
It normally reports a 01h in the PCI Configuration Header field Header Type, indicating multi-  
function capability. However, if a LAN id disabled, it reports a 0h in this filed to signify single-  
function capability.  
Interrupt Use  
When both LAN devices are enabled, the Ethernet controller uses both the INTA# and INTB# pins  
for interrupt-reporting. The EEPROM Initialization Control Word 3 (bit 4) associated with each  
LAN device controls which of these two pins is used for each LAN device. The specific interrupt  
pin used is reported in the PCI Configuration Header Interrupt Pin field associated with each LAN  
device.  
However, if either LAN device is disabled, then the INTA# be used for the remaining LAN device,  
regardless of the EEPROM configuration. Under these circumstances, the Interrupt Pin field of the  
PCI Header always reports a value of 1h, indicating INTA# usage.  
12.5.5  
Power Reporting  
When both LAN devices are enabled, the PCI Power Management Register Block has the  
capability of reporting a Common Power value. The Common Power value is reflected in the data  
field of the PCI Power Management registers. The value reported as Common Power is specified  
via EEPROM, and is reflected in the data field each time the Data_Select field has a value of 8h  
(8h = Common Power Value Select).  
When either LAN is disabled and the Ethernet controller appears as a single-function device, the  
Common Power value, if selected, reports 0h (undefined value), as Common Power is undefined  
for a single-function device.  
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12.5.6  
Summary  
The following table lists the various LAN enabled/disabled configurations possible:  
LAN  
Enabled/  
PCI  
function  
CVDR values sampled-on-reset  
FLSH_DATA[1] FLSH_DATA[0]  
Interrupt Line Used  
device Disabled  
INTA# or INTB# (specified by LAN A  
1
1
A
B
0
(enabled)  
EEPROM InitCtrl3 value)  
INTA# or INTB# (specified by LAN B  
1
0
(enabled)  
EEPROM InitCtrl3 value)  
0
1
A
B
÷
INTA#  
n/a  
X
n/a  
(disabled)  
1
0
0
0
A
B
A
B
C
X
X
X
n/a  
0
n/a  
INTA#  
n/a  
n/a  
n/a  
n/a  
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Register Descriptions  
13  
13.1  
Introduction  
This section details the state inside the PCI/PCI-X Family of Gigabit Ethernet Controllers that are  
visible to the programmer. In some cases, it describes hardware structures invisible to software in  
order to clarify a concept.  
The address space within the Ethernet controller is divided up into eight main categories:  
• PCI  
• General Configuration and Wakeup  
• Interrupt  
• MAC Receive  
• MAC Transmit  
• PHY Receive, Transmit and Special Function  
• Statistics  
• Diagnostic State (not used in normal operation)  
The Ethernet controller’s address space is mapped into four regions with PCI Base Address  
Registers described in Table 13-2. These regions are shown as follows.  
Internal registers and memories (including PHY)  
Flash (optional)  
Memory  
Memory  
Memory  
I/O  
128 KB  
64 - 512 KB  
64 - 512 KB  
8 Bytes  
Expansion ROM (optional)  
Internal registers and memories, Flash (optional)  
Both the Flash an Expansion ROM Base Address Registers map the same Flash memory. The  
internal registers and memories and Flash can be access through I/O space by doing a level of  
indirection, as explained later.  
Note: The PHY registers are accessed indirectly through the MDI/O interface described in Section 8.2.  
13.2  
Register Conventions  
All registers in the Ethernet controller are defined to be 32 bits, should be accessed as 32-bit double  
words, and are aligned on a 64-bit boundary. There are exceptions to this rule:  
• PCI configuration registers  
• I/O space registers (IOADDR and IODATA) are aligned on 32-bit boundaries  
• Register pairs where two 32-bit registers make up a larger logical size  
• Accesses to Flash memory (through Expansion ROM space or secondary Base Address  
Register space) can be byte, word, double word or quadword accesses.  
• Reserved bit positions. Some registers contain certain bits that are marked as “reserved.”  
These bits should never be set to a value of 1b by software. Reads from registers containing  
reserved bits can return indeterminate values in the reserved bit positions unless read values  
are explicitly stated. When read, these reserved bits should be ignored by software.  
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Register Descriptions  
• Reserved and/or undefined addresses. Any register not explicitly declared in this  
specification should be considered to be reserved and should not be written. Writing to  
reserved or undefined register addresses can cause indeterminate behavior. Reads from  
reserved or undefined configuration register addresses can return indeterminate values unless  
read values are explicitly stated for specific addresses.  
• Initial values. Most registers define the initial hardware values prior to being programmed. In  
some cases, hardware initial values are undefined and are listed as such via the text  
“undefined,” “unknown,” or “X.” Some such values might need setting through EEPROM  
configuration or software in order for proper operation to occur; this need is dependent on the  
function of the bit. Other registers might cite a hardware default that is overridden by a higher  
precedence operation. Operations that might supersede hardware defaults can include a valid  
EEPORM load, completion of a hardware operation (such as hardware Auto-Negotiation), or  
writing of a different register whose value is then reflected in another bit.  
For registers that should be accessed as 32-bit double words, partial writes (less than a 32-bit  
double word) is ignored. Partial reads return all 32 bits of data regardless of the byte enables.  
Partial reads to read-on-clear registers (for example, ICR) can have unexpected results since all 32  
bits are actually read regardless of the byte enables. Partial reads should not be performed.  
All statistics registers are implemented as 32-bit registers. 64-bit accesses to these registers must  
have the upper byte enables deasserted. 32-bit registers with addresses not on a quadword  
boundary cannot be accessed through a 64-bit access.  
Note: The PHY registers are accessed indirectly through the MDI/O interface.  
13.2.1  
Memory and I/O Address Decoding  
13.2.1.1  
13.2.1.2  
Memory-Mapped Access to Internal Registers and Memories  
The internal registers and memories can be accessed as direct memory-mapped offsets from the  
base address register (BAR0 or BAR0/BAR1, see Section 4.1). Refer to Table 13-2 for the  
appropriate offset for each specific internal register.  
Memory-Mapped Access to FLASH  
The external Flash can be accessed using direct memory-mapped offsets from the Flash base  
address register (BAR1 or BAR2/BAR3, see Section 4.1). The Flash is only accessible if enabled  
through the EEPROM Initialization Control Word, and if the Flash Base Address register contains  
a valid (non-zero) base memory address. For accesses, the offset from the Flash BAR corresponds  
to the offset into the flash actual physical memory space.  
13.2.1.3  
Memory-Mapped Access to Expansion ROM  
The external Flash can also be accessed as a memory-mapped expansion ROM. Accesses to offsets  
starting from the Expansion ROM Base address (see Section 4.1) reference the Flash provided that  
access is enabled through the EEPROM Initialization Control Word, and if the Expansion ROM  
Base Address register contains a valid (non-zero) base memory address.  
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Register Descriptions  
13.2.2  
I/O-Mapped Internal Register, Internal Memory, and Flash1  
To support pre-boot operation (prior to the allocation of physical memory base addresses), all  
internal registers, memories, and Flash can be accessed using I/O operations. I/O accesses are  
supported only if an I/O Base Address is allocated and mapped (BAR2 or BAR4, see Section 4.1),  
the BAR contains a valid (non-zero value), and I/O address decoding is enabled in the PCI/PCIX  
configuration.  
When an I/O BAR is mapped, the I/O address range allocated opens a 32-byte window in the  
system I/O address map. Within this window, two I/O addressable registers are implemented:  
IOADDR and IODATA. The IOADDR register is used to specify a reference to an internal register,  
memory, or Flash, and then the IODATA register is used as a window to the register, memory or  
Flash address specified by IOADDR:  
Offset  
Abbreviation  
Name  
RW  
Size  
Internal Register, Internal Memory, or Flash Location  
Address  
00000h - 1FFFFh — Internal Registers and Memories  
20000h - 7FFFFh — Undefined  
80000h - FFFFFh — Flash  
00000000h  
IOADDR  
RW 4 bytes  
Data field for reads or writes to the Internal Register Internal  
00000004h  
IODATA  
Memory, or Flash location as identified by the current value RW 4 bytes  
in IOADDR. All 32 bits of this register are read/write-able.  
13.2.2.1  
IOADDR  
The IOADDR register must always be written as a DWORD access (for example, the C/BE#[3:0]  
byte enables must all be enabled). Writes that are less than 32 bits are ignored. Reads of any size  
return a DWORD of data. However, the chipset or CPU can only return a subset of that DWORD.  
For Intel architecture programmers, the IN and OUT instructions must be used to cause I/O cycles  
to be used on the PCI bus. Since writes must be to a 32-bit quantity, the source register of the OUT  
instruction must be EAX (the only 32-bit register supported by the OUT command). For reads, the  
IN instruction can have any size target register, but it is recommended that the 32-bit EAX register  
be used.  
Since only a particular range is addressable, the upper bits of this register are hard coded to 0b. Bits  
31 through 20 are not write-able and always read back as 0b.  
At hardware reset (LAN_PWR_GOOD) or PCI Reset, this register value resets to 00h. Once  
written, the value is retained until the next write or reset.  
13.2.2.2  
IODATA  
The IODATA register must always be written as a DWORD access when the IOADDR register  
contains a value for the Internal Register and Memories (00000h - 1FFFCh). In this case, writes  
less than 32 bits are ignored.  
1. Not applicable to the 82547GI/EI.  
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Register Descriptions  
The IODATA register can be written as a byte, word, or Dword access when the IOADDR register  
contains a value for the Flash (80000h - FFFFFh). In this case, the value in IOADDR must be  
properly aligned to the data value. Additionally, the lower 2 bits of the IODATA PCI-X access must  
correspond to the byte, word, or Dword access.Table 13-1 lists the supported configurations:  
Table 13-1. IODATA Register Configurations  
Ethernet Controller  
IOADDR Register Bits  
[1:0]  
PCI-X1 IODATA Access  
AD[1:0] Bits in Address  
Phase  
PCI-X IODATA Access  
AD C/BE#[3:0] Bits in  
Data Phase  
Access Type  
BYTE (8 bits)  
00b  
01b  
10b  
11b  
00b  
10b  
00b  
00b  
01b  
10b  
11b  
00b  
10b  
00b  
1110b  
1101b  
1011b  
0111b  
1100b  
0011b  
0000b  
WORD (16 bits)  
DWORD (32 bits)  
1.  
The 82540EP/EM does not support PCI-X.  
Software might need to implement special code to access the Flash memory at a byte or word at a  
time. Example code that reads a Flash byte is shown here to illustrate the impact of Table 13-1:  
char *IOADDR;  
char *IODATA;  
IOADDR = IOBASE + 0;  
IODATA = IOBASE + 4;  
*(IOADDR) = Flash_Byte_Address;  
Read_Data = *(IODATA + (Flash_Byte_Address % 4));  
Reads to IODATA of any size returns a Dword of data. However, the chipset or CPU can only  
return a subset of that Dword.  
For Intel architecture programmers, the IN and OUT instructions must be used to cause I/O cycles  
to be used on the PCI bus. Where 32-bit quantities are required on writes, the source register of the  
OUT instruction must be EAX (the only 32-bit register supported by the OUT command).  
Writes and reads to IODATA when the IOADDR register value is in an undefined range (20000h -  
7FFFCh) should not be performed. Results are indeterminate.  
There are no special software timing requirements on accesses to IOADDR or IODATA. All  
accesses are immediate except when data is not readily available or acceptable. In this case, the  
Ethernet controller delays the results through normal bus methods.  
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Register Descriptions  
Table 13-2. Ethernet Controller Register Summary  
Category  
General  
General  
General  
Offset  
00000h  
Abbreviation  
CTRL  
Name  
R/W  
R/W  
Page  
224  
Device Control  
Device Status  
00008h  
00010h  
STATUS  
EECD  
R
229  
EEPROM/Flash Control/Data  
R/W  
232  
EEPROM Read (not applicable to the  
82544GC/EI)  
General  
General  
00014h  
0001Ch  
EERD  
FLA  
R/W  
R/W  
234  
236  
Flash Access (applicable to the 82541xx and  
82547GI/EI only)  
General  
General  
General  
General  
General  
General  
General  
00018h  
00020h  
00028h  
0002Ch  
00030h  
00038h  
00170h  
CTRL_EXT  
MDIC  
Extended Device Control  
MDI Control  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
237  
242  
283  
283  
284  
284  
285  
FCAL  
Flow Control Address Low  
Flow Control Address High  
Flow Control Type  
FCAH  
FCT  
VET  
VLAN EtherType  
FCTTV  
Flow Control Transmit Timer Value  
Transmit Configuration Word (not applicable to  
the 82540EP/EM, 82541xx and 82547GI/EI)  
General  
General  
General  
00178h  
00180h  
00E00h  
TXCW  
R/W  
R
286  
287  
289  
Receive Configuration Word (not applicable to  
the 82540EP/EM, 82541xx and 82547GI/EI)  
RXCW  
LEDCTL  
LED Control (not applicable to the 82544GC/  
EI)  
R/W  
DMA  
01000h  
000C0h  
PBA  
ICR  
Packet Buffer Allocation  
Interrupt Cause Read  
R/W  
R
292  
293  
Interrupt  
Interrupt Throttling (not applicable to the  
82544GC/EI)  
Interrupt  
000C4h  
ITR  
R/W  
295  
Interrupt  
Interrupt  
Interrupt  
Receive  
Receive  
Receive  
Receive  
Receive  
Receive  
Receive  
Receive  
Receive  
000C8h  
000D0h  
000D8h  
00100h  
02160h  
02168h  
02800h  
02804h  
02808h  
02810h  
02818h  
02820h  
ICS  
Interrupt Cause Set  
W
296  
297  
298  
300  
304  
305  
306  
306  
307  
307  
308  
308  
IMS  
Interrupt Mask Set/Read  
Interrupt Mask Clear  
R/W  
W
IMC  
RCTL  
FCRTL  
FCRTH  
RDBAL  
RDBAH  
RDLEN  
RDH  
Receive Control  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
Flow Control Receive Threshold Low  
Flow Control Receive Threshold High  
Receive Descriptor Base Low  
Receive Descriptor Base High  
Receive Descriptor Length  
Receive Descriptor Head  
Receive Descriptor Tail  
RDT  
RDTR  
Receive Delay Timer  
Receive Interrupt Absolute Delay Timer (not  
applicable to the 82544GC/EI)  
Receive  
Receive  
0282Ch  
02C00h  
RADV  
R/W  
R/W  
309  
310  
Receive Small Packet Detect Interrupt (not  
applicable to the 82544GC/EI)  
RSRPD  
Transmit  
Transmit  
Transmit  
Transmit  
Transmit  
Transmit  
Transmit  
Transmit  
Transmit  
00400h  
00410h  
00458h  
03800h  
03804h  
03808h  
03810h  
03818h  
03820h  
TCTL  
TIPG  
Transmit Control  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
310  
312  
314  
315  
316  
316  
317  
318  
318  
Transmit IPG  
AIFS  
Adaptive IFS Throttle - AIT  
Transmit Descriptor Base Low  
Transmit Descriptor Base High  
Transmit Descriptor Length  
Transmit Descriptor Head  
Transmit Descriptor Tail  
Transmit Interrupt Delay Value  
TDBAL  
TDBAH  
TDLEN  
TDH  
TDT  
TIDV  
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Register Descriptions  
Category  
TX DMA  
TX DMA  
TX DMA  
Offset  
03000h  
Abbreviation  
TXDMAC  
TXDCTL  
Name  
R/W  
R/W  
Page  
319  
TX DMA Control (applicable to the 82544GC/  
EI only)  
03828h  
0282Ch  
Transmit Descriptor Control  
R/W  
R/W  
319  
Transmit Absolute Interrupt Delay Timer (not  
applicable to the 82544GC/EI)  
TADV  
321  
TX DMA  
RX DMA  
RX DMA  
03830h  
02828h  
05000h  
TSPMT  
TCP Segmentation Pad and Threshold  
Receive Descriptor Control  
R/W  
R/W  
R/W  
322  
324  
325  
RXDCTL  
RXCSUM  
Receive Checksum Control  
05200h-  
053FCh  
Receive  
Receive  
Receive  
Receive  
MTA[127:0]  
RAL(8n)  
Multicast Table Array (n)  
Receive Address Low (n)  
Receive Address High (n)  
R/W  
R/W  
R/W  
R/W  
327  
329  
329  
330  
05400h-  
05478h  
05404h-  
0547Ch  
RAH(8n)  
VFTA[127:0]  
VLAN Filter Table Array (n)  
Not applicable to the 82541ER  
05600h-  
057FCh  
Wakeup  
Wakeup  
Wakeup  
Wakeup  
05800h  
05808h  
05810h  
05838h  
WUC  
WUFC  
WUS  
IPAV  
Wakeup Control  
Wakeup Filter Control  
Wakeup Status  
R/W  
R/W  
R
331  
332  
333  
335  
IP Address Valid  
R/W  
IP4AT  
IPAT (82544GC/  
EI)  
IPv4 Address Table  
IP Address Table (82544GC/EI)  
05840h-  
05858h  
Wakeup  
R/W  
336  
05880h-  
0588Ch  
IPv6 Address Table (not applicable to the  
82544GC/EI)  
Wakeup  
Wakeup  
Wakeup  
IP6AT  
WUPL  
WUPM  
R/W  
R/W  
R/W  
337  
338  
338  
05900h  
Wakeup Packet Length  
05A00h-  
05A7Ch  
Wakeup Packet Memory  
05F00h-  
05F18h  
Wakeup  
Wakeup  
Wakeup  
FFLT  
FFMT  
FFVT  
Flexible Filter Length Table  
Flexible Filter Mask Table  
Flexible Filter Value Table  
R/W  
R/W  
R/W  
338  
339  
340  
09000h-  
093F8h  
09800h-  
09BF8h  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
04000h  
04004h  
04008h  
0400Ch  
04010h  
04014h  
04018h  
0401Ch  
04020h  
04028h  
04030h  
04034h  
04038h  
0403Ch  
04040h  
04048h  
0404Ch  
04050h  
CRCERRS  
ALGNERRC  
SYMERRS  
RXERRC  
MPC  
CRC Error Count  
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
341  
341  
342  
342  
343  
343  
344  
344  
345  
345  
346  
346  
347  
347  
348  
348  
349  
349  
Alignment Error Count  
Symbol Error Count  
RX Error Count  
Missed Packets Count  
Single Collision Count  
Excessive Collisions Count  
Multiple Collision Count  
Late Collisions Count  
Collision Count  
SCC  
ECOL  
MCC  
LATECOL  
COLC  
DC  
Defer Count  
TNCRS  
SEC  
Transmit - No CRS  
Sequence Error Count  
Carrier Extension Error Count  
Receive Length Error Count  
XON Received Count  
XON Transmitted Count  
XOFF Received Count  
CEXTERR  
RLEC  
XONRXC  
XONTXC  
XOFFRXC  
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Category  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Offset  
04054h  
Abbreviation  
XOFFTXC  
FCRUC  
PRC64  
PRC127  
PRC255  
PRC511  
PRC1023  
PRC1522  
GPRC  
Name  
R/W  
Page  
349  
350  
350  
351  
351  
352  
352  
353  
353  
354  
354  
355  
355  
355  
356  
356  
356  
357  
357  
358  
358  
XOFF Transmitted Count  
R
04058h  
0405Ch  
04060h  
04064h  
04068h  
0406Ch  
04070h  
04074h  
04078h  
0407Ch  
04080h  
04088h  
0408Ch  
04090h  
04094h  
040A0h  
040A4h  
040A8h  
040ACh  
040B0h  
FC Received Unsupported Count  
Packets Received (64 Bytes) Count  
Packets Received (65-127 Bytes) Count  
Packets Received (128-255 Bytes) Count  
Packets Received (256-511 Bytes) Count  
Packets Received (512-1023 Bytes) Count  
Packets Received (1024-Max Bytes)  
Good Packets Received Count  
Broadcast Packets Received Count  
Multicast Packets Received Count  
Good Packets Transmitted Count  
Good Octets Received Count (Low)  
Good Octets Received Count (Hi)  
Good Octets Transmitted Count (Low)  
Good Octets Transmitted Count (Hi)  
Receive No Buffers Count  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R
BPRC  
R
MPRC  
R
GPTC  
R
GORCL  
GORCH  
GOTCL  
GOTCH  
RNBC  
R
R
R
R
R
RUC  
Receive Undersize Count  
R
RFC  
Receive Fragment Count  
R
ROC  
Receive Oversize Count  
R
RJC  
Receive Jabber Count  
R
Management Packets Received Count (not  
applicable to the 82544GC/EI or 82541ER)  
Statistics  
Statistics  
Statistics  
040B4h  
040B8h  
040BCh  
MGTPRC  
MGTPDC  
MGTPTC  
R
R
R
359  
360  
360  
Management Packets Dropped Count (not  
applicable to the 82544GC/EI or 82541ER)  
Management Pkts Transmitted Count (not  
applicable to the 82544GC/EI or 82541ER)  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
Statistics  
040C0h  
040C4h  
040C8h  
040CCh  
040D0h  
040D4h  
040D8h  
040DCh  
040E0h  
040E4h  
040E8h  
TORL  
Total Octets Received (Lo)  
R
R
R
R
R
R
R
R
R
R
R
360  
360  
361  
361  
362  
362  
363  
363  
364  
364  
365  
TORH  
TOTL  
Total Octets Received (Hi)  
Total Octets Transmitted (Lo)  
TOTH  
Total Octets Transmitted (Hi)  
TPR  
Total Packets Received  
TPT  
Total Packets Transmitted  
PTC64  
PTC127  
PTC255  
PTC511  
PTC1023  
Packets Transmitted (64 Bytes) Count  
Packets Transmitted (65-127 Bytes) Count  
Packets Transmitted (128-255 Bytes) Count  
Packets Transmitted (256-511 Bytes) Count  
Packets Transmitted (512-1023 Bytes) Count  
Packets Transmitted (1024 Bytes or Greater)  
Count  
Statistics  
040ECh  
PTC1522  
R
365  
Statistics  
Statistics  
Statistics  
Statistics  
040F0h  
040F4h  
040F8h  
040FCh  
MPTC  
BPTC  
Multicast Packets Transmitted Count  
Broadcast Packets Transmitted Count  
R
R
366  
366  
367  
367  
368  
368  
369  
369  
370  
370  
TSCTC  
TSCTFC  
RDFH  
TCP Segmentation Context Transmitted Count R  
TCP Segmentation Context Tx Fail Count  
Receive Data FIFO Head  
R
Diagnostic 02410h  
Diagnostic 02418h  
Diagnostic 02420h  
Diagnostic 02428h  
Diagnostic 02430h  
Diagnostic 03410h  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
RDFT  
Receive Data FIFO Tail  
RDFHS  
RDFTS  
RDFPC  
TDFH  
Receive Data FIFO Head Saved Register  
Receive Data FIFO Tail Saved Register  
Receive Data FIFO Packet Count  
Transmit Data FIFO Head  
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Register Descriptions  
Category  
Offset  
Abbreviation  
TDFT  
Name  
Transmit Data FIFO Tail  
R/W  
R/W  
Page  
371  
Diagnostic 03418h  
Diagnostic 03420h  
Diagnostic 03428h  
Diagnostic 03430h  
TDFHS  
Transmit Data FIFO Head Saved Register  
Transmit Data FIFO Tail Saved Register  
Transmit Data FIFO Packet Count  
R/W  
R/W  
R/W  
371  
TDFTS  
372  
TDFPC  
372  
10000h-  
Diagnostic  
PBM  
Packet Buffer Memory (n)  
R/W  
373  
1FFFCh  
Note: The PHY registers are accessed indirectly through the MDI/O interface described in Section 8.2.  
MDI  
Register  
Category  
PHY  
Abbreviation  
PCTRL  
Name  
PHY Control Register  
R/W  
R/W  
Page  
00d  
245  
248  
250  
250  
251  
255  
258  
259  
260  
261  
262  
263  
264  
267  
270  
272  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
PHY  
01d  
02d  
03d  
04d  
05d  
06d  
07d  
08d  
09d  
10d  
15d  
16d  
17d  
18d  
19d  
PSTATUS  
PID  
PHY Status Register  
R
PHY Identifier (LSB)  
R
EPID  
Extended PHY Identifier (MSB)  
Auto-Negotiation Advertisement Register  
Link Partner Ability Register (Base Page)  
Auto-Negotiation Expansion Register  
Next Page Transmit Register  
Link Partner Next Page Register  
1000BASE-T Control Register  
1000BASE-T Status Register  
Extended PHY Status Register  
PHY Specific Control Register  
PHY Specific Status Register  
PHY Interrupt Enable  
R
ANA  
R/W  
R
LPA  
ANE  
R
NPT  
R/W  
R
LPN  
GCON  
GSTATUS  
EPSTATUS  
PSCON  
PSSTAT  
PINTE  
PINTS  
R/W  
R
R
R/W  
R
R/W  
R
PHY Interrupt Status  
EPSCON1  
EPSCON (82544GC/  
EI)  
PHY  
20d  
Extended PHY Specific Control 1  
PHY Receive Error Counter  
R/W  
275  
PHY  
PHY  
21d  
PREC  
R
R
277  
279  
PHY Global Status  
23d1  
PGSTAT  
SPEED_TEN_LED and LINK_ACT_LED2  
PHY LED Control  
PHY  
PHY  
24d1  
PLED  
R/W  
280  
281  
SPEED_100_LED and  
SPEED_1000_LED2  
Extended PHY Specific Status (not  
26d  
EPSCON2  
applicable to the 82540EP/EM or 82544GC/ R/W  
EI)  
PHY  
PHY  
27d3  
29d  
EPSSTAT  
R30PS  
Extended PHY Specific Status  
R/W  
281  
281  
Register 30 Page Select (not applicable to  
the 82544GC/EI, 82541xx, or 82547GI/EI)  
W
Register 30 Access Window (not applicable  
PHY  
PHY  
30d  
31d  
R30AW  
PPAGE  
to the 82544GC/EI, 82541xx, or 82547GI/ R/W  
EI)  
282  
283  
Page Select (82541xx and 82547GI/EI  
R/W  
only)  
1.  
2.  
3.  
Applicable to the 82544GC/EI, 82541xx, and 82547GI/EI only.  
Applicable to the 82541xx, and 82547GI/EI only.  
Applicable to the 82544GC/EI only.  
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1
13.3  
PCI-X Register Access Split  
The PCI-X specification states that accesses to internal device memory spaces must complete  
within a specific target initial latency, or else the device should signal that it completes the  
transaction later using a split-completion operation. Due to internal access latencies, read accesses  
to most device registers in the Ethernet controller exceeds target initial-access latencies, and  
therefore are split.  
Once a register read operation has been split, the device may, as part of normal operation, initiate a  
large inbound or outbound transmit or receive data burst transaction. The split completion for the  
pending register read might be forced to wait until the data burst completes. Therefore, the read  
access-delay for most registers can be indeterminate (although is generally bounded by the nature  
or normal burst transactions).  
A small subset of the internal register space has been identified as most critical for high-perfor-  
mance driver execution. The variable completion delay for access to some registers could  
potentially limit the performance of such critical routines as Interrupt Service Routines (ISRs). To  
help minimize potential critical routine performance, read accesses to a small subset of internal  
register space will instead complete without being split. These registers are listed as follows:  
Category  
General  
General  
General  
General  
General  
General  
General  
General  
General  
General  
General  
General  
General  
Interrupt  
Interrupt  
Offset  
00000h  
Abbreviation  
CTRL  
Name  
Device Control Register  
Device Status Register  
00008h  
00010h  
00018h  
00020h  
00028h  
0002Ch  
00030h  
00038h  
00170h  
00178h  
00180h  
01000h  
000C0h  
000C8h  
STATUS  
EECD  
CTRL_EXT  
MDIC  
EEPROM/Flash Control/Data Register  
Extended Device Control Register  
MDI Control Register  
FCAL  
Flow Control Address Low  
Flow Control Address High  
Flow Control Type  
FCAH  
FCT  
VET  
VLAN Ether Type  
FCTTV  
TXCW  
RXCW  
PBA  
Flow Control Transmit Timer Value  
Transmit Configuration Word  
Receive Configuration Word  
Packet Buffer Allocation  
Interrupt Cause Read  
ICR  
ICS  
Interrupt Cause Set  
1. Not applicable to the 82540EP/EM, 82541xx, or 82547GI/EI.  
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Register Descriptions  
Category  
Interrupt  
Interrupt  
Transmit  
Offset  
000D0h  
000D8h  
00400h  
Abbreviation  
IMS  
Name  
Interrupt Mask Set/Read  
IMC  
Interrupt Mask Clear  
Transmit Control  
TCTL  
The EEPROM configuration bit “Force CSR Read Split” (Initialization Control Word 2, word 0Fh)  
provides the ability to configure the device to split all internal register accesses, rather than  
providing non-split behavior for the registers listed.  
13.4  
Main Register Descriptions  
This section contains detailed register descriptions for general purpose, DMA, interrupt, receive,  
and transmit registers. These registers correspond to the main functions of the Ethernet controller.  
13.4.1  
Device Control Register  
CTRL (00000h; R/W)  
This register and the Extended Device Control register (CTRL_EXT) control the major operational  
modes for the Ethernet controller.  
While software writes to this register to control device settings, several bits (such as FD and  
SPEED) can be overridden depending on other bit settings and the resultant link configuration  
determined by the PHY’s Auto-Negotiation resolution.  
Note: TBI Mode is used only by the 82544GC/EI Ethernet controller. Internal SerDes mode is used only  
by the 82546GB/EB and 82545GM/EM Ethernet controllers.  
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Register Descriptions  
Table 13-3. CTRL Register Bit Description  
31  
0
Device Control Bits  
Initial  
Value  
Field  
Bit(s)  
Description  
Full-Duplex  
Enables software to override the hardware Auto-Negotiation  
function. The FD sets the duplex mode only if CTRL.FRCDPLX  
is set.  
When cleared, the Ethernet controller operates in half-duplex;  
when set, the Ethernet controller operates in full-duplex.  
When the Ethernet controller operates in TBI mode/internal  
SerDes mode, and the AN Hardware is enabled, this bit is  
ignored. When the Ethernet controller operates in TBI mode/  
internal SerDes, and the AN Hardware is disabled, or the link is  
forced, this bit should be set by software.  
1b  
0b1  
FD  
0
When the Ethernet controller operates in internal PHY mode,  
the FD bit is set by software based on AN and data rate  
resolution.  
Configurable through the EEPROM.  
Reserved  
2:1  
0b  
1b  
These bits are reserved and should be set to 00b.  
Link Reset (not applicable to the 82540EP/EM, 82541xx, or  
82547GI/EI)  
0b = Normal; 1b = Link Reset  
Applicable only in TBI mode/internal SerDes of operation. Used  
to reset the link control logic and restart the Auto-Negotiation  
process, when TXCW.ANE is set and TBI mode/internal SerDes  
is enabled.  
LRST  
3
When set, transmission and reception are halted regardless of  
TBI mode/internal SerDes setting. A transition to 0b initiates the  
Auto-Negotiation function. Configurable from the EEPROM,  
allowing initiation of Auto-Negotiation function at power up.  
Reserved  
Reserved  
ASDE  
4
5
0b  
0b  
Factory use only. Should be written with 0b.  
Auto-Speed Detection Enable.  
When set, the Ethernet controller automatically detects the  
resolved speed of the link by sampling the link in internal PHY  
mode and self-configures the appropriate status and control  
bits. Software must also set the SLU bit for this operation. This  
function is ignored in TBI mode/internal Serdes. The ASD  
feature provides a method of determining the link speed without  
the need for software accesses to the MII management  
registers.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Set Link Up  
In TBI mode/internal SerDes, provides manual link  
configuration. When set, the Link Up signal is forced high once  
receiver synchronization is achieved (LOS not asserted) using  
CTRL.FD to determine the duplex mode. This operation  
bypasses the link configuration process. If Auto-Negotiation is  
enabled (TXCW.ANE equals 1b), then Set Link Up is ignored.  
In internal PHY mode, this bit must be set to 1b to permit the  
Ethernet controller to recognize the I_LOS/I_LIND link signal  
from the PHY.  
SLU  
6
0b  
The "Set Link Up" is normally initialized to 0b. However, if either  
the APM Enable or SMBus Enable bits are set in the EEPROM  
then it is initialized to 1b, ensuring MAC/PHY communication  
during preboot states (for example, the 82547EI and 82541EI).  
Driver software sets this bit when the driver software initializes,  
therefore LED indications (link, activity, speed) are not active  
until the software driver loads even though the PHY has auto-  
negotiated and established link with a partner on the Ethernet.  
See Section 8.6 for more information about Auto-Negotiation  
and link configuration in the various modes.  
Configurable through the EEPROM.  
Invert Loss-of-Signal (LOS).  
0b = do not invert (active high input signal); 1b = invert signal  
(active low input signal).  
If using the internal PHY, this bit should be set to 0b to ensure  
proper communication with the MAC. If using an external TBI  
device, this bit can be set if the Ethernet controller provides a  
link loss indication with negative polarity.  
ILOS  
7
0b  
Note: This is a reserved bit for the 82541xx and 82547GI/EI.  
Speed selection.  
These bits determine the speed configuration and are written by  
software after reading the PHY configuration through the MDI/O  
interface. These signals are ignored in TBI mode/internal  
Serdes or when Auto-Speed Detection (CTRL.ASDE) is  
enabled. See Section 8.6 for details.  
00b 10 Mb/s  
01b 100 Mb/s  
10b 1000 Mb/s  
11b not used  
SPEED  
9:8  
10  
10b  
Reserved  
Reserved  
0b  
Should be written with 0b to ensure future compatibility.  
Force Speed  
When set, the Ethernet controller speed is configured by  
CTRL.SPEED bits. The PHY device must resolve to the same  
speed configuration or software must manually set it to the  
same speed as the Ethernet controller.  
FRCSPD  
11  
1b  
When cleared, this allows the PHY device or ASD function  
(CTRL.ASDE is set) to set the Ethernet controller speed.  
This bit is superseded by the CTRL_EXT.SPD_BYPS bit, which  
has a similar function.  
Applicable only in internal PHY mode of operation and is  
configurable through EEPROM.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Force Duplex  
When set, software can override the duplex indication from the  
PHY which is in internal PHY mode. When set the CTRL.FD bit  
sets duplex. When cleared, the CTRL.FD is ignored.  
FRCDPLX  
12  
0b  
0b  
Reserved  
Reserved  
17:13  
18  
Should be written with 0b to ensure future compatibility.  
Read as 0b  
SDP0 Data Value. Used to read (write) value of software-  
controllable IO pin SDP0. If SDP0 is configured as an output  
(SDP0_IODIR=1b), this bit controls the value driven on the pin  
(initial value EEPROM-configurable). If SDP0 is configured as  
an input, reads return the current value of the pin.  
SDP0_DATA  
0b2  
SDP1 Data Value. Used to read (write) value of software-  
controllable IO pin SDP1. If SDP1 is configured as an output  
(SDP1_IODIR=1b), this bit controls the value driven on the pin  
(initial value EEPROM-configurable). If SDP1 is configured as  
an input, reads return the current value of the pin.  
SDP1_DATA  
ADVD3WUC  
19  
20  
0b2  
D3Cold Wakeup Capability Advertisement Enable. When set,  
D3Cold wakeup capability is advertised based on whether the  
AUX_PWR pin advertises presence of auxiliary power (yes if  
AUX_PWR is indicated, no otherwise). When 0b, however,  
D3Cold wakeup capability is not advertised even if AUX_PWR  
presence is indicated. Formerly used as SDP2 pin data value,  
initial value is EEPROM-configurable.  
0b2  
Note: Not applicable to the 82541ER.  
PHY Power-Management Enable. When set, the PHY is  
informed of power-state transitions and attempts to auto-  
negotiate advertising lower line speeds only (10 or 100 Mb/sec)  
when entering D3 or D0u power states with wakeup or  
manageability enabled. It again re-negotiates, advertising full  
speed capabilities (10/100/1000 Mbps) when transitioning back  
to full D0 operational state. If this bit is clear, the PHY automatic  
speed/power management capability is disabled, and the PHY  
remains operational at its current line speed through power-  
state transitions. Formerly used as SDP3 pin data value, initial  
value is EEPROM-configurable.  
0b2  
1b1  
EN_PHY_  
PWR_MGMT  
21  
SDP0 Pin Directionality. Controls whether software-controllable  
pin SDP0 is configured as an input or output (0b = input, 1b =  
output). Initial value is EEPROM-configurable. This bit is not  
affected by software or system reset, only by initial power-on or  
direct software writes.  
SDP0_IODIR  
22  
0b2  
SDP1 Pin Directionality. Controls whether software-controllable  
pin SDP1 is configured as an input or output (0b = input, 1b =  
output). Initial value is EEPROM-configurable. This bit is not  
affected by software or system reset, only by initial power-on or  
direct software writes.  
SDP1_IODIR  
Reserved  
23  
0b2  
0b  
Reserved. Formerly used as SDP2and SDP3 pin input/output  
direction control.  
25:24  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Device Reset  
0b = normal; 1b = reset. Self clearing.  
When set, it globally resets the entire Ethernet controller with  
the exception of the PCI configuration registers. All registers  
(receive, transmit, interrupt, statistics, etc.), and state machines  
are set to their power-on reset values. This reset is equivalent to  
a PCI reset, with the one exception being that the PCI  
configuration registers are not reset.  
RST  
26  
0b  
To ensure that global device reset has fully completed and that  
the Ethernet controller responds to subsequent access, wait  
approximately 1 s after setting and before attempting to check  
to see if the bit has cleared or to access any other device  
register.  
Receive Flow Control Enable.  
When set, indicates that the Ethernet controller responds to the  
reception of flow control packets. Reception and responding to  
flow control packets requires matching the content of the  
Ethernet controller’s FCAL/H and FCT registers. If Auto-  
Negotiation is enabled, this bit is set to the negotiated flow  
control value. See Section 8.6 for more information about Auto-  
Negotiation.  
RFCE  
27  
0b  
Transmit Flow Control Enable.  
When set, indicates that the Ethernet controller transmits flow  
control packets (XON and XOFF frames) based on the receive  
FIFO fullness, or when triggered to do so based on external  
control pins (XOFF XON pins when FCTRH.XFCE is set). If  
Auto-Negotiation is enabled, this bit is set to the negotiated flow  
control value. See Auto-Negotiation for more information.  
TFCE  
28  
29  
0b  
0b  
Reserved.  
Reserved  
Should be written with 0b to ensure future compatibility. Read as  
0b.  
VLAN Mode Enable  
When set to 1b, all packets transmitted from the Ethernet  
controller that have VLE bit set in their descriptor is sent with an  
802.1Q header added to the packet. The contents of the header  
come from the transmit descriptor and from the VLAN type  
register. On receive, VLAN information is stripped from 802.1Q  
packets and is loaded to the packet’s descriptor. See Section  
9.2 for more details.  
VME  
30  
0b  
Reserved. Should be written with 0b to ensure future  
compatibility.  
Note: Not applicable to the 82541ER.  
PHY Reset  
0b = Normal.  
1b = Assert hardware reset to the internal PHY.  
The technique is to set the bit, wait approximately 3 s, then  
clear the bit. For the 82547GI/82541GI (B1 stepping), this  
register must be used instead of a PHY register.  
Note: For the 82546GB, when resetting the PHY through the  
MAC, the PHY should be held in reset for a minimum of 10 ms  
before releasing the reset signal.  
PHY_RST  
31  
0b  
1.  
2.  
82541xx and 82547GI/EI only.  
If the signature bits of the EEPROM’s Initialization Control Word 1 match (01b), these bits are read from the EEPROM.  
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Register Descriptions  
The ADVD3WUC bit (Advertise D3Cold Wakeup Capability Enable control) allows the  
AUX_PWR pin to determine whether D3Cold support is advertised. If full 1 Gb/s operation in D3  
state is desired but the system’s power requirements in this mode would exceed the D3Cold  
Wakeup-Enabled specification limit (375 mA at 3.3 V dc), this bit can be used to prevent the  
capability from being advertised to the system.  
EEPROM settings allow the default PHY behavior to re-negotiate a lower functional link speed in  
D3 and D0u states, when PHY operation is still needed for manageability or wakeup capability.  
The EN_PHY_PWR_MGMT bit allows this capability to be disabled, in case full 1Gb/s speed is  
desired in these states. The PHY is always powered-down in D3 states when unneeded for either  
manageability or wakeup support.  
Table 13-4. Little-Endian Data Ordering  
BEM = 0 (64-bit mode; Little-Endian)  
63  
0
08  
10  
07  
0f  
06  
0e  
05  
0d  
04  
0c  
03  
0b  
02  
0a  
01  
09  
13.4.2  
Device Status Register  
STATUS (00008h; R)  
This register provides software status indication about the Ethernet controller’s settings and modes  
of operation.  
Note: TBI Mode is used only by the 82544GC/EI Ethernet controller. Internal SerDes mode is used only  
by the 82546GB/EB and 82545GM/EM Ethernet controllers.  
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Register Descriptions  
Table 13-5. Status Register Bit Description  
31  
13 12  
0
Reserved  
Status  
Initial  
Value  
Field  
Bit(s)  
Description  
Link Full Duplex configuration Indication  
When cleared, the Ethernet controller operates in half-duplex;  
when set, the Ethernet controller operates in Full duplex.  
The FD provides the duplex setting status of the Ethernet  
controller as set by either Hardware Auto-Negotiation function,  
or by software.  
FD  
LU  
0
X
X
Link Up Indication  
0b = no link config; 1b = link config.  
For TBI mode/internal SerDes operation: If Auto-Negotiation is  
enabled, this bit is set if a valid link is negotiated. If link is forced  
through CTRL.SLU, it reflects the status of this control bit.  
For internal PHY mode of operation: Reflects the status of the  
internal link signal indicating a transition to a Link Up.  
See Section 8.6 for more information about Auto-Negotiation.  
1
Function ID.  
Provides software a mechanism to determine the Ethernet  
controller function number (LAN identifier) for this MAC. Read  
as: [0b,0b] LAN A, [0b,1b] LAN B.  
Function ID  
3:2  
0b  
Note: These settings are only applicable to the 82546GB/EB.  
For all other Ethernet controllers, set these bits to 0b.  
Transmission Paused  
When set, Indicates the transmit function is in Pause state due  
to reception of an XOFF pause frame when symmetrical flow  
control is enabled. It is cleared upon expiration of the pause  
timer, or receipt of an XON frame. Applicable only while working  
in full-duplex flow-control mode of operation.  
TXOFF  
4
X
TBI Mode/internal SerDes Indication  
When set, the Ethernet controller is configured to work in TBI  
mode/internal SerDes of operation.  
When clear, the Ethernet controller is configured to work in  
internal PHY mode.  
TBIMODE  
5
X
Note: For the 82544GC/EI, reflects the status of the TBI_MODE  
input pin.  
For all other Ethernet controllers, set this bit to 0b.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Link speed setting  
Indicates the configured speed of the link.  
These bits are either forced by software when forcing the link  
speed through the CTRL.SPEED control bits, automatically set  
by hardware when Auto-Speed Detection is enabled or reflect  
the internal indication inputs from the PHY.  
When Auto-Speed Detection is enabled, the Ethernet  
controller’s speed is configured only once after the internal link  
is asserted.  
SPEED  
7:6  
X
Speed indication is mapped as follows:  
00b = 10 Mb/s  
01b = 100 Mb/s  
10b = 1000 Mb/s  
11b = 1000 Mb/s  
These bits are not valid in TBI mode/internal SerDes.  
Auto Speed Detection Value  
Indicates the speed sensed by the Ethernet controller from the  
internal PHY. The ASDV status bits are provided for diagnostics  
purposes. The ASD function can be initiated by software writing  
a logic 1b to the CTRL_EXT.ASDCHK bit. The resultant speed  
detection is reflected in these bits. See Section 13.4.6 for  
details.  
ASDV  
9:8  
X
Reserved  
Reads as 0b.  
Reserved  
PCI66  
10  
11  
X
X
PCI Bus speed indication  
When set, indicates that the PCI bus is running at 66 MHz.  
Reflects the M66EN input pin.  
Note: Not applicable to the 82547GI/EI.  
PCI Bus Width indication  
When set, indicates that the Ethernet controller is sitting on a  
64-bit PCI/PCI-X bus. BUS64 is determined by REQ64#  
assertion.  
BUS641  
12  
13  
X
X
PCIX_MODE1  
PCI-X Mode indication  
When set to 1b, the Ethernet controller is operating in PCI-X  
Mode; otherwise, the Ethernet controller is operating in  
conventional PCI Mode.  
PCIXSPD1  
15:14  
X
PCI-X Bus Speed Indication  
Attempts to indicate the speed of the bus when operating in a  
PCI-X bus. Only valid when STATUS.PCIX_Mode = 1b.  
00b = 50-66 MHz  
01b = 66-100 MHz  
10b = 100-133 MHz  
11b = Reserved  
Reserved  
31:16  
0b  
Reserved  
Reads as 0b.  
1.  
Not applicable to the 82540EP/EM, 82541xx, or 82547GI/EI.  
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Register Descriptions  
13.4.3  
EEPROM/Flash Control & Data Register  
EECD (00010h; R/W)  
This register provides a simplified interface for software accesses to the EEPROM. Software  
controls the EEPROM by successive writes to this register.  
Data and address information is clocked into the EEPROM by software toggling the EECD.SK bit  
(2) of this register with EECD.CS set to 1b.  
Data output from the EEPROM is latched into bit 3 of this register and can be accessed by software  
through reads of this register.  
See Section 5 for more detailed EEPROM information.  
Table 13-6. EECD Register Bit Description  
31 - 10  
9
8
7
6
5
4
3
2
1
0
D
O
Reserved  
SIZE  
PRES  
GNT  
REQ  
FWE  
DI CS SK  
82544GC/EI Only  
31  
6 5  
4
3
2
1
0
Reserved  
FWE  
DO DI CS SK  
Initial  
Value  
Field  
Bit  
Description  
Clock input to the EEPROM  
The EESK output signal is mapped to this bit and provides the  
serial clock input to the EEPROM. Software clocks the EEPROM  
by means of toggling this bit with successive writes to EECD.  
SK  
0
0b  
Chip select input to the EEPROM  
The EECS output signal is mapped to the chip select of the  
EEPROM device. Software enables the EEPROM by writing a 1b  
to this bit.  
CS  
DI  
1
2
3
0b  
0b  
X
Data input to the EEPROM  
The EEDI output signal is mapped directly to this bit. Software  
provides data input to the EEPROM through writes to this bit.  
Data output bit from the EEPROM  
The EEDO input signal is mapped directly to this bit in the register  
and contains the EEPROM data output. This bit is read-only from  
the software perspective – writes to this bit have no effect.  
DO  
Flash Write Enable Control  
These two bits, control whether writes to Flash memory are  
allowed.  
00b = Not allowed  
FWE  
5:4  
01b  
01b = Flash writes disabled  
10b = Flash writes enabled  
11b = Not allowed  
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Register Descriptions  
Initial  
Value  
Field  
Bit  
Description  
Request EEPROM Access  
The software must write a 1b to this bit to get direct EEPROM  
access. It has access when EE_GNT is 1b. When the software  
completes the access it must write a 0b.  
EE_REQ  
61  
71  
81  
0b  
Grant EEPROM Access  
When this bit is 1b the software can access the EEPROM using the  
SK, CS, DI, and DO bits.  
EE_GNT  
0b  
EEPROM Present  
1b  
This bit indicates that an EEPROM is present by monitoring the  
EEDO input for a active-low acknowledge by the serial EEPROM  
during initial EEPROM scan. 1b = EEPROM present.  
EE_PRES  
0b2  
EEPROM Size  
0b = 1024-bit (64 word) NM93C46 compatible EEPROM  
1b = 4096-bit (256 word) NM93C66 compatible EEPROM  
This bit indicates the EEPROM size, based on acknowledges seen  
during EEPROM scans of different addresses. This bit is read-only.  
Note: This is a reserved bit for the 82541xx and 82547GI/EI.  
EE_SIZE  
EE_SIZE  
91  
0b  
0b  
EEPROM Size (82541xx and 82547GI/EI)  
For Microwire EEPROMs:  
0b = 6-bit addressable (64 words).  
1b = 8-bit addressable (256 words).  
For SPI EEPROMs:  
101  
0b = 8-bit addressable.  
1b = 16-bit addressable.  
Reserved  
Reserved  
EE_TYPE  
Reserved  
12:11  
131  
00b  
1b  
Should be written with 0b to ensure future compatibility. Reads as  
0b.  
EEPROM Type: Reflects the EE_MODE pin. (82541xx and  
82547GI/EI)  
0b = Microwire.  
1b = SPI.  
Reserved  
31:14  
0b  
Should be written with 0b to ensure future compatibility. Reads as  
0b.  
1.  
2.  
Not applicable to the 82544GC/EI.  
82541xx and 82547GI/EI only.  
This register provides software direct access to the EEPROM. Software can control the EEPROM  
by successive writes to this register. Data & address information is clocked into the EEPROM by  
software toggling the EESK bit (2) of this register with EECS set to 1b. Data output from the  
EEPROM is latched into bit 3 of this register via the internal 62.5 MHz clock and can be accessed  
by software via reads of this register.  
Note: Attempts to write to the FLASH device when writes are disabled (FEW = 01b) should not be  
attempted. Behavior after such an operation is undefined, and can result in component and/or  
system hangs.  
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Register Descriptions  
13.4.4  
EEPROM Read Register1  
EERD (00014h; RW)  
Table 13-7. EEPROM Read Register Bit Description  
31  
16  
15  
8
7
5
4
3
1
0
Data  
Address  
RSV.  
DONE  
RSV.  
START  
Initial  
Value  
Field  
Bit(s)  
Description  
Start Read  
Writing a 1b to this bit causes the EEPROM to read a (16-bit) word at  
the address stored in the EE_ADDR field and then storing the result in  
the EE_DATA field. This bit is self-clearing.  
START  
0
0b  
Reserved  
DONE  
3:1  
4
0b  
0b  
Reserved. Reads as 0b.  
Read Done  
Set to 1b when the EEPROM read completes.  
Set to 0b when the EEPROM read is in progress.  
Writes by software are ignored.  
Reserved  
ADDR  
7:5  
0b  
X
Reserved. Reads as 0b.  
Read Address  
15:8  
31:16  
This field is written by software along with Start Read to indicate the  
word to read.  
DATA  
X
Read Data. Data returned from the EEPROM read.  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
Table 13-8. EEPROM Read Register Bit Description (82541xx and 82547GI/EI)  
31  
16  
15  
2
1
0
Data  
Address  
DONE  
START  
Initial  
Value  
Field  
Bit(s)  
Description  
Start Read  
Writing a 1b to this bit causes the EEPROM to read a (16-bit) word at  
the address stored in the EE_ADDR field and then storing the result in  
the EE_DATA field. This bit is self-clearing.  
START  
0
1
0b  
Read Done  
Set to 1b when the EEPROM read completes.  
Set to 0b when the EEPROM read is in progress.  
Writes by software are ignored.  
DONE  
0b  
Read Address  
ADDR  
DATA  
15:2  
X
X
This field is written by software along with Start Read to indicate the  
word to read.  
31:16  
Read Data. Data returned from the EEPROM read.  
This register is used by software to cause the Ethernet controller to read individual words in the  
EEPROM. To read a word, software writes the address to the Read Address field and simultane-  
ously writes a 1b to the Start Read field. The Ethernet controller reads the word from the EEPROM  
and places it in the Read Data field, setting the Read Done filed to 1b. Software can poll this  
register, looking for a 1b in the Read Done filed, and then using the value in the Read Data field.  
When this register is used to read a word from the EEPROM, that word is not written to any of  
Ethernet controller’s internal registers even if it is normally a hardware accessed word.  
Note: If software has requested direct pin control of the EEPROM using the EEC register, an access  
through the EERD register mechanism can stall until the EEC control has been released. Software  
should ensure that EEC.EE_REQ = 0b and that EEC.EE_GNT = 0b as well before attempting to  
use EERD to access the EEPROM.  
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Register Descriptions  
13.4.5  
Flash Access1  
FLA (0001Ch; R/W)  
This register provides software direct access to the Flash memory. Software can control the Flash  
device by successive writes to this register. Data and address information is clocked into the Flash  
memory by software toggling the FL_SCK bit (0) of this register with FL_CE set to 1b. Data  
output from the Flash memory is latched into bit three of this register via the internal 125 MHz  
clock and is accessed by software via reads of this register.  
Table 13-9. Flash Access – FLA  
31  
30  
29 - 6  
5
4
3
2
1
0
FL  
ER  
FL  
BS  
FL  
FL  
FL  
SO  
FL  
SI  
FL  
CS  
FL  
SCK  
Reserved  
GNT REQ  
Initial  
Value  
Field  
Bit(s)  
Description  
Clock Input to the FLASH.  
When FL_GNT is 1b, the FL_SCK out signal is mapped to this bit and  
provides the serial clock input to the Flash device. Software clocks the  
Flash memory via toggling this bit with successive writes.  
FL_SCK  
0
0b  
Chip FL Input to the FLASH.  
When FL_GNT is 1b, the FL_CS output signal is mapped to the chip  
select of the device. Software enables the FLASH by writing a 0b to this  
bit.  
FL_CE  
FL_SI  
1
2
3
0b  
0b  
X
Data Input to the FLASH.  
When FL_GNT is 1b, the FL_DI output signal is mapped directly to this  
bit. Software provides data input to the FLASH via writes to this bit.  
Data Output Bit from the FLASH.  
The FL_SO input signal is mapped directly to this bit in the register and  
contains the Flash memory serial data output. This bit is read only from  
the software perspective — writes to this bit have no effect.  
FL_SO  
Request FLASH Access.  
The software must write a 1b to this bit to get direct Flash memory  
access. It has access when FL_GNT is 1b. When the software  
completes the access it must write a 0b.  
FL_REQ  
4
5
0b  
Grant FLASH Access.  
When this bit is 1b, the software can access the Flash memory using  
the FL_SCK, FL_CE, FL_SI, and FL_SO bits.  
FL_GNT  
0
0
Reserved.  
Reads as 0b.  
Reserved  
29:6  
Flash Busy.  
This bit is set to 1b while a write or an erase to the Flash memory is in  
progress. While this bit is clear (read as 0b) software can access to  
write a new byte to the Flash device.  
FL_BUSY  
FL_ER  
30  
31  
0
0
Flash Erase Command.  
This command will be sent to the Flash component only if bits 5:4 are  
also set. This bit is automatically cleared and read as 0b.  
1. Applicable to the 82541xx and 82547GI/EI only.  
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Register Descriptions  
13.4.6  
Extended Device Control Register  
CTRL_EXT (00018h, R/W)  
This register and the Device Control register (CTRL) controls the major operational modes for the  
Ethernet controller. CTRL_EXT provides extended control of the Ethernet controller functionality  
over the Device Control register (CTRL).  
Note: See Table 13-12 and Table 13-13 for the 82544GC/EI.  
Table 13-10. CTRL_EXT Register Bit Description  
31 - 24  
23 - 16 15  
Extended Device Control Bits  
0
Reserved  
Initial  
Value  
Field  
Bit(s)  
Description  
Reserved bits for the 82541xx and 82547GI/EI. Should be written  
as 0b to ensure future compatibility.  
Reserved  
1:0  
0b  
General Purpose Interrupt Enables  
These bits determine whether the upper three software definable  
pins SDP[7:6] and SDP[4] are mapped to the ICR.GPI interrupt  
bits. These mappings are enabled only when the SDP[7:6] and  
SDP[4] pins are configured as inputs through  
CTRL_EXT.SWDPIOHI. Refer to Table 13-11 for SDP to ICR.GPI  
bit mapping.  
GPI_EN  
GPI_EN  
3:0  
3:2  
0b  
0b  
General Purpose Interrupt Enables for the 82541xx and 82547GI/  
EI.  
These bits determine whether the upper software definable pins  
SDP[3:2] are mapped to the ICR.GPI interrupt bits. These  
mappings are enabled only when the SDP[3:2] pins are configured  
as inputs through CTRL_EXT.SWDPIOHI. Refer to Table 13-11 for  
SDP to ICR.GPI bit mapping.  
Reserved  
PHYINT  
4
5
0b  
0b  
Reserved. Formally used as SDP4 pin data value. Reads as 0b.  
PHY Interrupt Value. When read, returns the current value of the  
PHY internal interrupt status PHYINT.  
Note: This is a reserved bit for the 82541xx and 82547GI/EI.  
SDP6_DATA  
SDP6[2] Data Value. Used to read (write) value of software-  
controllable IO pin SDP6[2]. If SDP6[2] is configured as an output  
(SDP6[2]_IODIR = 1b), this bit controls the value driven on the pin  
(initial value EEPROM-configurable). If SDP6[2] is configured as  
an input, reads return the current value of the pin.  
6
0b1  
SDP2_DATA  
(82541xx and  
82547GI/EI)  
SDP7_DATA  
SDP7[3] Data Value. Used to read (write) value of software-  
controllable IO pin SDP7[3]. If SDP7[3] is configured as an output  
(SDP7[3]_IODIR = 1b), this bit controls the value driven on the pin  
(initial value EEPROM-configurable). If SDP7[3] is configured as  
an input, reads return the current value of the pin.  
7
0b1  
01b  
SDP3_DATA  
(82541xx and  
82547GI/EI)  
Reserved  
Reserved  
9:8  
Should be written as 01b to ensure future compatibility.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
SDP6_IODIR  
SDP6[2] Pin Directionality. Controls whether software-controllable  
pin SDP6[2] is configured as an input or output (0b = input, 1b =  
output). Initial value is EEPROM-configurable. This bit is not  
affected by software or system reset, only by initial power-on or  
direct software writes.  
10  
0b1  
SDP2_IODIR  
(82541xx and  
82547GI/EI)  
SDP7_IODIR  
SDP7[2] Pin Directionality. Controls whether software-controllable  
pin SDP7[2] is configured as an input or output (0b = input, 1b =  
output). Initial value is EEPROM-configurable. This bit is not  
affected by software or system reset, only by initial power-on or  
direct software writes.  
11  
12  
0b1  
SDP2_IODIR  
(82541xx and  
82547GI/EI)  
ASD Check  
Initiate an Auto-Speed-Detection (ASD) sequence to sense the  
frequency of the PHY receive clock. The results are reflected in  
STATUS.ASDV. This bit is self-clearing.  
ASDCHK  
0b  
This functionality is provided for diagnostic purposes, regardless of  
whether the Auto Speed Detection feature is enabled. This bit is  
applicable only for internal PHY mode of operation.  
EEPROM Reset  
When set, initiates a reset-like event to the EEPROM function. This  
causes the EEPROM to be read as if a RST# assertion had  
occurred. All device functions should be disabled prior to setting  
this bit. This bit is self-clearing.  
EE_RST  
Reserved  
13  
14  
0b  
0b1  
Reserved. Should be set to 0b.  
Speed Select Bypass  
When set to 1b, all speed detection mechanisms are bypassed,  
and the Ethernet controller is immediately set to the speed  
indicated by CTRL.SPEED. This can be used to override the  
hardware clock switching circuitry and give full control to software.  
SPD_BYPS differs from the CTRL.FRCSPD function in that  
FRCSPD uses the internal clock switching circuitry rather than an  
immediate forcing function of the speed settings, as does  
SPD_BYPS.  
SPD_BYPS  
15  
0b  
Reserved  
RO-DIS  
16  
17  
0b1  
Reserved. Should be set to 0b.  
Relaxed Ordering Disabled  
When set to 1b, the Ethernet controller does not request any  
relaxed ordering transactions in PCI-X mode regardless of the  
state of bit 1 in the PCI-X command register. When this bit is clear  
and bit 1 of the PCI-X command register is set, the Ethernet  
controller requests relaxed ordering transactions.  
Note: This is a reserved bit for the 82540EP/EM, 82541xx, and  
82547GI/EI. Set to 0b.  
0b  
Reserved  
Reserved  
20:18  
0b  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Voltage Regulator Power Down (82541xx and 82547GI/EI only)  
0b = Normal operation.  
VREG POWER  
DOWN  
1b = Voltage regulators power down.  
This bit is initialized from the EEPROM.  
Note: This is a reserved bit for all remaining Ethernet controllers.  
Set to 0b.  
21  
0b  
Link Mode. This controls which interface is used to talk to the link.  
00b = Direct copper (1000Base-T) interface (GMII/MII internal PHY  
mode)  
01b = Reserved  
10b = Direct Fiber interface (using internal SerDes)  
11b = external TBI interface  
Note: These are reserved bits for the 82540EP/EM, 82541xx, and  
82547GI/EI. Set to 00b  
LINK_MODE  
Reserved  
23:22  
31:24  
0b  
0b  
Reserved  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
1.  
These bits are read from the EEPROM  
The Ethernet controller allows for up to two externally controlled interrupts. The upper two  
software-definable pins, SDP[7:6] (SDP[3:2] for the 82541xx and 82547GI/EI), can be mapped  
for use as GPI interrupt bits. These mappings are enabled by the SDPx_GPIEN bits only when  
these signals are also configured as inputs via SDPx_IODIR. When configured to function as  
external interrupt pins, a GPI interrupt is generated when the corresponding pin is sampled in an  
active-high state.  
The bit mappings are shown in Table 13-11 for clarity.  
Table 13-11. GPI to SDP Bit Mappings  
SDP pin to be used as  
GPI  
Resulting ICR bit  
(GPI)  
CTRL_EXT field settings  
Enable as GPI interrupt  
Directionality  
SDP7_IODIR  
SDP2_IODIR1  
SDP6_IODIR  
SDP3_IODIR1  
7
SDP7_GPIEN  
SDP2_GPIEN1  
SDP6_GPIEN  
SDP3_GPIEN1  
14  
13  
21  
6
31  
1.  
82541xx and 82547GI/EI only  
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Register Descriptions  
Table 13-12. 82544GC/EI CTRL_EXT Register Bit Description  
31  
16 15  
0
Reserved  
Extended Device Control Bits  
Initial  
Value  
Field  
Bit(s)  
Description  
General Purpose Interrupt Enables  
These bits determine whether the upper three software  
definable pins SDP[7:6] and SDP[4] are mapped to the ICR.GPI  
interrupt bits. These mappings are enabled only when the  
SDP[7:6] and SDP[4] pins are configured as inputs through  
CTRL_EXT.SWDPIOHI. Refer to Table 13-13 for SDP to  
ICR.GPI bit mapping.  
GPI_EN  
3:0  
0
0
Software Defined Pins – high nibble  
These three bits allow direct control of SDP[7:6] and SDP[4].  
These pins can be either input pins or output pins as  
determined by the SWDPIOHI bits. The initial direction of the  
software defined pins is read out of the EEPROM.  
Note: SDP[5] and its associated bit is not used. It should be  
programmed to 0b for future compatibility.  
SWDPINSHI  
7:6, 4  
Software Defined Pins Input or Output  
These three bits control whether each of the high nibble  
software defined pins SDP[7:6] and SDP[4] is used as an input  
or an output.  
0b = inputs; 1b = outputs.  
This field is not affected by assertion of software reset  
(CTRL.RST).  
SWDPIOHI  
11:10, 8  
0
Configurable through EEPROM.  
Note: SDP[5] and its associated bit is not used. It should be  
programmed to 0b for future compatibility.  
ASD Check  
Initiate an Auto-Speed-Detection (ASD) sequence to sense the  
frequency of the PHY receive clock. The results are reflected in  
STATUS.ASDV. This bit is self-clearing.  
This functionality is provided for diagnostic purposes,  
regardless of whether the Auto Speed Detection feature is  
enabled. This bit is applicable only for internal PHY mode of  
operation.  
ASDCHK  
12  
0
EEPROM Reset  
When set, initiates a “reset-like” event to the EEPROM function.  
This causes the EEPROM to be read as if a RST# assertion had  
occurred. All Ethernet controller functions should be disabled  
prior to setting this bit. This bit is self-clearing.  
EE_RST  
13  
14  
0
0
Invert Power State Bit 0  
When set to 1b, inverts the assertion polarity of the  
PWR_STATE bit 0 output. When cleared to 0b, PWR_STATE is  
logic high in normal operation.  
IPS  
Configurable through EEPROM.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Speed Select Bypass  
When set to 1b, all speed detection mechanisms are bypassed,  
and the Ethernet controller is immediately set to the speed  
indicated by CTRL.SPEED. This might be used to override the  
hardware clock switching circuitry and give full control to  
software. SPD_BYPS differs from the CTRL.FRCSPD function  
in that FRCSPD uses the internal clock switching circuitry rather  
than an immediate forcing function of the speed settings, as  
does SPD_BYPS.  
SPD_BYPS  
15  
0
0
Invert Power State Bit 1  
Inverts the polarity of bit 1 of the PWR_STATE signal when set  
to 1b.  
IPS1  
16  
Configurable through the EEPROM.  
Relaxed Ordering Disabled  
When set to 1b, the Ethernet controller does not request any  
relaxed ordering transactions in PCI-X mode regardless of the  
state of bit 1 in the PCI-X command register. When this bit is  
clear and bit 1 of the PCI-X command register is set, the  
Ethernet controller requests relaxed ordering transactions as  
described.  
RO-DIS  
17  
0
0
Reserved  
Reserved  
31:18  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
Table 13-13. 82544GC/EI GPI to SDP Bit Mapping  
CTRL_EXT  
(SWDPINHI)  
CTRL_EXT  
(GPI_EN)  
ICR  
(GPI)  
B_SDP  
7
6
5
4
7
3
14  
13  
6
Reserved  
4
2
Reserved  
0
Reserved  
11  
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Register Descriptions  
13.4.7  
MDI Control Register  
MDIC (00020h; R/W)  
Software uses this register to read or write Management Data Interface (MDI) registers in the  
internal PHY.  
To read a location in the PHY, first perform an MDI write cycle with the following bit settings:  
• Ready = 0b  
• Interrupt Enable programmed to 1b or 0b  
• Opcode = 10b (read)  
• PHYADD = PHY address from the MDI register  
• REGADD = Register address within the PHY to be read  
When the serial data transfer from PHY to MAC is complete, the Ethernet controller issues an  
interrupt if the MDI interrupt is enabled. The Ethernet controller also sets the Ready bit. This  
indication tells the system that the read data is available from the 16-bit data field in the MDI  
Control register. Perform a second read operation to the register at this time to recover the data.  
To write a location in the PHY, perform an MDI write cycle with the following bit settings:  
• Ready = 0b  
• Interrupt Enable programmed to 1b or 0b  
• Opcode = 01b (write)  
• PHYADD = PHY address from the MDI register  
• REGADD = Register address within the PHY to be written  
• Data = Specific data for PHY operation  
If enabled, the Ethernet controller issues an interrupt when the write completes. The Ethernet  
controller also sets the Ready bit, denoting that a subsequent operation can be carried out.  
Note: The internal PHY register bit descriptions follow Table 13-14.  
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Register Descriptions  
Table 13-14. MDI Control Register Bit Description  
31  
30  
29  
28  
27 26 25 21 20 16 15  
OP PHY REG  
0
RSV  
E
I
R
DATA  
Initial  
Value  
Field  
Bit(s)  
Description  
Data  
In a Write command, software places the data bits and the  
Ethernet controller shifts them out to the PHY. In a Read  
command, the Ethernet controller reads these bits serially from  
the PHY and software can read them from this location.  
DATA  
15:0  
X
REGADD  
PHYADD  
20:16  
25:21  
0b  
0b  
PHY Register Address: Reg. 0, 1, 2, ...31  
PHY Address  
The Internal PHY’s MDI address for each MAC is 0001b  
Opcode  
01b = MDI Write  
10b = MDI Read  
All other values are reserved.  
OP  
27:26  
0b  
Ready Bit  
Set to 1b by the Ethernet controller at the end of the MDI  
transaction (for example, indication of a Read or Write  
completion). It should be reset to 0b by software at the same  
time the command is written.  
R
I
28  
29  
0b  
0b  
Interrupt Enable  
When set to 1b by software, it causes an Interrupt to be  
asserted to indicate the end of an MDI cycle.  
Error  
This bit is set to 1b by hardware when it fails to complete an  
MDI read. Software should make sure this bit is clear (0b)  
before issuing an MDI read or write command.  
E
30  
31  
0b  
0b  
Reserved  
Reads as 0b.  
Reserved  
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Register Descriptions  
13.4.7.1  
PHY Registers  
This document uses a special nomenclature to define the read/write mode of individual bits in each  
register. See Table 13-15.  
For all binary equations appearing in the register map, the symbol “|” is equivalent to a binary OR  
operation.  
Table 13-15. PHY Register Bit Mode Definitions  
Register Mode  
LH  
Description  
Latched High. Event is latched and erased when read.  
Latched Low. Event is latched and erased when read. For  
example, Link Loss is latched when the PHY Control  
Register bit 2 = 0b. After read, if the link is good, the PHY  
Control Register bit 2 is set to 1b.  
LL  
RO  
Read Only.  
R/W  
Read and Write.  
Self-Clear. The bit is set, automatically executed, and then  
reset to normal operation.  
SC  
Clear after Read. For example, 1000BASE-T Status  
Register bits 7:0 (Idle Error Counter).  
CR  
Value written to the register bit does not take effect until  
software PHY reset is executed.  
Update  
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Register Descriptions  
13.4.7.1.1  
PHY Control Register  
PCTRL (00d; R/W)  
Table 13-16. PHY Control Register Bit Description  
Field  
Reserved  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
RO  
These bits are reserved and should be  
set to 000000b.  
Always  
000000b  
5:0  
RW1  
Speed Selection is determined by bits 6  
(MSB) and 13 (LSB) as follows.  
11b = Reserved  
10b = 1000 Mbps  
01b = 100 Mbps  
00b = 10 Mbps  
A write to these bits do not take effect  
until a software reset is asserted,  
Restart Auto-Negotiation is asserted, or  
Power Down transitions from power  
down to normal operation.  
Speed Selection  
(MSB)  
6
R/W  
1b  
Update  
82544GC/EI only:  
The Speed Selection bits take on the  
values set by external pins ANEG[3:0]  
on hardware reset only.  
ANEG[3:2]  
MODE[3:0]  
Bit 6: ANEG[3] | ANEG[2] | (MODE[3:0]  
is one of xx01b, 1x00b, 001xb, 0111b).  
Bit 13: (ANEG[3:1] = 001b) and  
(MODE[3:0] is not any of xx01b, 1x00b,  
001xb, 0111b).  
1b = Enable COL signal test.  
0b = Disable COL signal test.  
Collision Test  
Duplex Mode  
7
8
R/W  
R/W  
0b  
1b  
0b  
1b = Full Duplex.  
0b = Half Duplex.  
82544GC/EI only:  
The Duplex bit takes on the value set by  
external pins ANEG[3:2, 0] on hardware  
reset only.  
Bit 8: ANEG[3:2,0] = 001 | ANEG[3].  
A write to this bit does not take effect  
until a software reset is asserted,  
Restart Auto-Negotiation is asserted, or  
Power Down transitions from power  
down to normal power.  
Update  
ANEG[3:2,  
0]  
1b = Restart Auto-Negotiation Process.  
0b = Normal operation.  
Restart Auto-  
Negotiation  
R/W,  
SC  
Self  
Clear  
Auto-Negotiation automatically restarts  
after hardware or software reset  
regardless of whether or not the restart  
bit is set.  
9
0b  
0b  
1b = Isolate.  
0b = Normal operation.  
Isolate  
10  
R/W  
0b  
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Register Descriptions  
Table 13-16. PHY Control Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Power down.  
0b = Normal operation.  
Power down shuts down the Ethernet  
controller except for the MAC interface if  
the MAC interface power down bit is set  
to 1b. If it equals 0b, then the MAC  
interface also shuts down. For the  
82544GC/EI, power down has no effect  
on the 125CLK output if the Disable  
125CLK bit is set to 0b.  
NOTE: Setting this bit to 1b will prevent  
wakeup by detecting circuitry  
on the CAT5 cable. To enable  
wakeup, this bit must be written  
back to 0b.  
Power Down  
11  
R/W  
0b  
0b  
82544GC/EI only:  
If bit 12 is set to 0b and speed is  
manually forced to 1000 Mb/s in bits 13  
and 6, then Auto-Negotiation is still  
enabled and only 1000BASE-T full  
duplex is advertised if bit 8 is set to 1b.  
1000BASE-T half duplex is advertised if  
bit 8 is cleared (0b). Duplex settings in  
other registers are ignored. Auto-  
Negotiation is required by IEEE for  
proper operation in 1000BASE-T.  
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Register Descriptions  
Table 13-16. PHY Control Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Enable Auto-Negotiation Process.  
0b = Disable Auto-Negotiation Process.  
A write to this bit does not take effect  
until a software reset is asserted,  
Restart Auto-Negotiation is asserted, or  
Power Down transitions from power  
down to normal operation.  
When the port is switched from power  
down to normal operation, software  
reset and restart Auto-Negotiation are  
performed even if bits Reset and Restart  
Auto-Negotiation are not set by the  
programmer.  
R/W  
Update  
1b  
If bit 12 is set to 0b and speed is  
manually forced to 1000 Mbps in bits 13  
and 6, then Auto-Negotiation is still  
enabled and only 1000BASE-T full  
duplex is advertised if bit 8 is set to 1b.  
1000BASE-T half duplex is advertised if  
bit 8 is cleared (0b). Duplex settings in  
other registers are ignored. Auto-  
Negotiation is required by IEEE for  
proper operation in 1000BASE-T.  
82544GC/EI only:  
Auto-Negotiation  
Enable  
12  
R/W  
Update  
ANEG[3:2]  
ENA_XC  
Auto-Negotiation enable takes on the  
value set by external pins ANEG[3:0] on  
hardware reset only.  
Bit 12: ANEG[3:2] = 11b.  
If MODE[3:0] equals 001xb or 0111b,  
where x equals either 0b or 1b, then the  
ANE bit determines whether  
1000BASE-X Auto-Negotiation is on or  
off. Otherwise ANE determines whether  
10/100/1000BASE-T Auto-Negotiation  
is on or off.  
R/W  
R/W  
0b  
Update  
0b  
Speed Selection  
(LSB)  
13  
See Speed Selection (MSB), bit 6.  
ANEG[3:1]2  
MODE[3:0]  
1b = Enable loopback.  
0b = Disable loopback.  
Loopback  
Reset  
14  
15  
0b  
0b  
1b = PHY reset.  
0b = Normal operation.  
R/W,  
SC  
Self  
Clear  
1.  
2.  
82541xx and 82547GI/EI only.  
82544GC/EI only.  
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Register Descriptions  
13.4.7.1.2  
PHY Status Register  
PSTATUS (01d; R)  
Table 13-17. PHY Status Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Extended Capability  
0
1b = Extended register capabilities.  
RO  
Always 1b  
1b = Jabber condition detected.  
0b = Jabber condition not detected.  
RO,L  
H
Jabber Detect  
Link Status  
1
2
0b  
0b  
0b  
1b = Link is up.  
0b = Link is down.  
This register indicates whether link was  
lost after the last read. For the current  
link status, either read this register  
back-to-back or read the Link Real Time  
bit 17 in the PHY Specific Status  
Register.  
RO,  
LL  
0b  
Auto-Negotiation  
Ability  
1b = PHY able to perform Auto-  
Negotiation.  
3
4
RO  
Always 1b  
0b  
1b = Remote fault condition detected.  
0b = Remote fault condition not  
detected.  
RO,L  
H
Remote Fault  
0b  
0b  
1b = Auto-Negotiation process  
complete.  
0b = Auto-Negotiation process not  
complete.  
Auto-Negotiation  
Complete  
5
6
RO  
RO  
0b  
Always 1b  
MF Preamble  
Suppression  
1b = PHY accepts management frames  
with preamble suppressed.  
(0b for the 82541xx  
and 82547GI/EI)  
Reserved  
7
8
Reserved. Should be set to 0b  
RO  
RO  
Always 0b  
Always 1b  
1b = Extended status information in the  
Extended PHY Status Register (15d).  
Extended Status  
100BASE-T2 Half  
Duplex  
0b = PHY not able to perform half  
duplex 100BASE-T2.  
9
RO  
RO  
Always 0b  
Always 0b  
100BASE-T2 Full  
Duplex  
0b = PHY not able to perform full duplex  
100BASE-T2.  
10  
1b = PHY able to perform half duplex  
10BASE-T.  
RO  
RO  
1b  
0b = PHY not able to perform half  
duplex 10BASE-T.  
82544GC/EI only:  
Bit 14 = Bit 13 = Bit 12 = Bit 11 =  
(MODE[3:0] is not any of xx01b, 1x00b,  
001xb, 0111b).  
10 Mb/s Half Duplex  
11  
MODE[3:0]  
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Register Descriptions  
Table 13-17. PHY Status Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = PHY able to perform full duplex  
10BASE-T.  
RO  
RO  
1b  
0b = PHY not able to perform full duplex  
10BASE-T.  
82544GC/EI only:  
Bit 14 = Bit 13 = Bit 12 = Bit 11 =  
(MODE[3:0] is not any of xx01b, 1x00b,  
001xb, 0111b).  
10 Mb/s Full Duplex  
12  
MODE[3:0]  
1b = PHY able to perform half duplex  
100BASE-X.  
RO  
RO  
1b  
0b = PHY able to perform half duplex  
100BASE-X.  
82544GC/EI only:  
Bit 14 = Bit 13 = Bit 12 = Bit 11 =  
(MODE[3:0] is not any of xx01b, 1x00b,  
001xb, 0111b).  
100BASE-X Half  
Duplex  
13  
MODE[3:0]  
1b = PHY able to perform full duplex  
100BASE-X.  
RO  
RO  
1b  
0b = PHY not able to perform full duplex  
100BASE-X.  
82544GC/EI only:  
Bit 14 = Bit 13 = Bit 12 = Bit 11 =  
(MODE[3:0] is not any of xx01b, 1x00b,  
001xb, 0111b).  
100BASE-X Full  
Duplex  
14  
15  
MODE[3:0]  
0b = PHY not able to perform 100BASE-  
T4.  
100BASE-T4  
RO  
Always 0b  
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Register Descriptions  
13.4.7.1.3  
PHY Identifier Register (LSB)  
PID (02d; R)  
Table 13-18. PHY Identifier Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
0000_0001_0100_0001b  
OUI is 005043h.  
Always 0141h  
Organizationally  
Unique Identifier Bit  
18:31  
15:0  
RO  
The PHY identifier composed of bits 3  
through 18 of the OUI (Organizationally  
Unique Identifier)2  
Always 02A8h2  
1.  
2.  
PHY ID number for the 82541xx and 82547GI/EI only.  
82541xx and 82547GI/EI only.  
13.4.7.1.4  
Extended PHY Identifier Register (MSB)  
EPID (03d; R)  
Table 13-19. Extended PHY Identifier Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
Always static  
00h1  
SW Rst  
Contains the current revision number.  
Revision Number  
3:0  
RO  
4 bits containing the manufacturer’s  
revision number.1  
Always 000010b  
000010b = 10/100/1000 Copper PHY.  
82544GC/EI only:  
82544GC/EI only:  
Model Number  
9:4  
RO  
RO  
Always 000011b  
000011b = 10/100/1000 Copper PHY.  
Always 111000b1  
6 bits containing the manufacturer’s part  
number1  
Organizationally  
Unique Identifier Bit  
19:24  
(PHY ID Number for  
the 82541xx and  
82547GI/EI)  
Always 000011b  
0h1  
000011b.  
15:10  
The PHY identifier composed of bits 19  
through 24 of the OUI1  
1.  
82541xx and 82547GI/EI only.  
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Register Descriptions  
13.4.7.1.5  
Auto-Negotiation Advertisement Register  
ANA (04d; R/W)  
Table 13-20. Auto-Negotiation Advertisement Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
00001b = 802.3  
For the 82541xx and 82547GI/EI:  
Other combinations are reserved.  
RO  
Always 00001b  
Unspecified or reserved combinations  
should not be transmitted.  
Selector Field  
4:0  
Note: Setting this field to a value other  
than 00001b can cause auto  
negotiation to fail.  
1b = Advertise.  
1b  
0b = Not advertised.  
Values programmed in the Auto-  
Negotiation Advertisement Register  
have no effect unless Auto-  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
10BASE-TX Half  
Duplex  
This bit can be overridden by the PHY R/W  
Control Register.  
Retain  
5
82544GC/EI only:  
10Base-T (82541xx  
and 82547GI/EI)  
ANEG[3:1]  
MODE[3:0]  
Bit 5: (ANEG[3:0] = 0000b |  
ANEG[3:2] = 11b) and (MODE[3:0] is  
not any of xx01b, 1x00b, 001xb,  
0111b).  
82541xx and 82547GI/EI only:  
1b = DTE is 10BASE-T capable.  
0b = DTE is not 10BASE-T capable.  
1b  
1b  
1b = Advertise.  
0b = Not advertised.  
Values programmed in the Auto-  
Negotiation advertisement register  
have no effect unless Auto-  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
10BASE-TX Full  
Duplex  
This bit can be overridden by the PHY  
Control Register.  
R/W  
Retain  
6
82544GC/EI only:  
10Base-T Full Duplex  
(82541xx and  
82547GI/EI)  
Bit 5: (ANEG[3:0] = 0001b |  
ANEG[3:2] = 11b) and (MODE[3:0] is  
not any of xx01b, 1x00b, 001xb,  
0111b).  
ANEG[3:0]  
MODE[3:0]  
82541xx and 82547GI/EI only:  
1b  
1b = DTE is 10BASE-T full duplex  
capable.  
0b = DTE is not 10BASE-T full duplex  
capable.  
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Register Descriptions  
Table 13-20. Auto-Negotiation Advertisement Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Advertise.  
1b  
0b = Not advertised.  
Values programmed in the Auto-  
Negotiation advertisement register  
have no effect unless Auto-  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
100BASE-TX Half  
Duplex  
This bit can be overridden by the PHY  
Control Register.  
R/W  
Retain  
7
82544GC/EI only:  
100Base-TX  
(82541xx and  
82547GI/EI)  
Bit 5: (ANEG[3:0] = 0010b |  
ANEG[3:2] = 11b) and (MODE[3:0] is  
not any of xx01b, 1x00b, 001xb,  
0111b).  
ANEG[3:1]  
MODE[3:0]  
82541xx and 82547GI/EI only1:  
1b  
1b = DTE is 100BASE-TX capable.  
0b = DTE is not 100BASE-TX  
capable.  
1b = Advertise.  
1b  
0b = Not advertised.  
Values programmed in the Auto-  
Negotiation advertisement register  
have no effect unless Auto-  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
This bit can be overridden by the PHY  
Control Register.  
R/W  
Retain  
100BASE-TX Full  
Duplex  
8
82544GC/EI only:  
ANEG[3:0]  
MODE[3:0]  
Bit 8: (ANEG[3:0] = 0011b |  
ANEG[3:2] = 11b) and (MODE[3:0] is  
not any of xx01b, 1x00b, 001xb,  
0111b).  
82541xx and 82547GI/EI only:1  
1b  
1b = DTE is 100BASE-TX full duplex  
capable.  
0b = DTE is not 100BASE-TX full  
duplex capable.  
100BASE-T4  
9
0b = Not capable of 100BASE-T4.  
RO  
Always 0b  
0b  
1b = MAC PAUSE implemented.  
0b = MAC PAUSE not implemented.  
Values programmed in the Auto-  
Negotiation advertisement register  
have no effect unless Auto-  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
1b for the  
(82541xx  
and  
PAUSE  
10  
R/W  
Retain  
82541xx and 82547GI/EI only:  
82547GI/  
EI)  
Advertise to Partner that Pause  
operation (as defined in 802.3x) is  
desired.  
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Register Descriptions  
Table 13-20. Auto-Negotiation Advertisement Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Asymmetric Pause.  
0b = No asymmetric Pause.  
0b  
Values programmed in the Auto-  
Negotiation advertisement register  
have no effect unless Auto-  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
Asymmetric Pause  
1b for the  
(82541xx  
and  
11  
R/W  
Retain  
ASM_DIR for the  
(82541xx and  
82547GI/EI)  
82541xx and 82547GI/EI only:  
82547GI/  
EI)  
Advertise Asymmetric Pause direction  
bit. This bit is used in conjunction with  
PAUSE.  
This bit is reserved and equals 0b.  
Values programmed in the Auto-  
Negotiation advertisement register  
have no effect unless Auto-  
Reserved  
12  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
R/W  
0b  
Retain  
Reserved bit is R/W to allow for  
forward compatibility with future IEEE  
standards.  
1b = Set Remote Fault bit.  
0b = Do not set Remote Fault bit.  
Values programmed in the Auto-  
Negotiation advertisement register  
have no effect unless Auto-  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
Remote Fault  
Reserved  
13  
14  
R/W  
RO  
0b  
Retain  
Reserved. Should be set to 0b.  
Always 0b  
1b = Advertise.  
0b = Not advertised.  
Values programmed in the Auto-  
Negotiation advertisement register  
have no effect unless Auto-  
Negotiation is restarted (PHY Control  
Register) or link goes down.  
If 1000BASE-T is advertised then the  
Next Page  
15  
required next pages are automatically R/W  
transmitted. The Next Page bit should  
equal 0 if no additional next pages are  
needed.  
0b  
Retain  
82541xx and 82547GI/EI only:  
1b = Manual control of Next Page  
(Software).  
0b = Ethernet controller control of Next  
Page (Auto).  
1.  
For the 82541xx and 82547GI/EI, if EEPROM bit ADV10LU is asserted, then the default is set to 0b. Otherwise, the default  
is 1b.  
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Register Descriptions  
82544GC/EI Only:  
Table 13-21. Auto-Negotiation Advertisement Register Bit Description  
(MODE[3:0] is one of 001xb, 0111b)  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
restarted (PHY Control Register) or the  
link goes down.  
Reserved  
4:0  
R/W  
00000b  
Retain  
Reserved bit is R/W to allow forward  
compatibility with future IEEE standards.  
1b = Advertise  
0b = Not advertised  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
restarted (PHY Control Register) or the  
link goes down.  
1000BASE-X Full  
Duplex  
5
6
R/W  
R/W  
ANEG[3]  
ANEG[2]  
Retain  
Retain  
Bit 5: ANEG[3] = 1b  
1b = Advertise  
0b= Not advertised  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
restarted (PHY Control Register) or the  
link goes down.  
1000BASE-X Half  
Duplex  
Bit 6: ANEG[2] = 1b  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
restarted (PHY Control Register) or the  
link goes down.  
Pause  
7
8
R/W  
R/W  
0b  
Retain  
Retain  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
restarted (PHY Control Register) or the  
link goes down.  
Asymmetric Pause  
000b  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
restarted (PHY Control Register) or the  
link goes down.  
Reserved bit is R/W to allow forward  
compatibility with future IEEE standards.  
Reserved  
11:9  
R/W  
R/W  
0b  
0b  
Retain  
Retain  
Retain  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
restarted (PHY Control Register) or the  
link goes down.  
Ethernet controller has no ability to  
detect remote fault.  
RF1  
12  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
restarted (PHY Control Register) or the  
link goes down.  
Ethernet controller has no ability to  
detect remote fault.  
RF2  
13  
14  
R/W  
RO  
0b  
Reserved  
Reserved. Should be set to 0b.  
Always 0b  
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Register Descriptions  
Table 13-21. Auto-Negotiation Advertisement Register Bit Description  
(MODE[3:0] is one of 001xb, 0111b)  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
0b = Not advertised  
Values programmed in this register have  
no effect unless Auto-Negotiation is  
Next Page  
15  
restarted (PHY Control Register) or the RO  
link goes down.  
Always 0b  
Next Page is not supported in  
1000BASE-X mode.  
13.4.7.1.6  
Link Partner Ability Register (Base Page)  
LPA (05d; R)  
Table 13-22. Link Partner Ability Register (Base Page) Bit  
1
Description  
Field  
Bit(s)  
4:0  
Description  
Mode  
HW Rst  
00000b  
SW Rst  
Selector Field  
Received Code Word Bit 4:0.  
RO  
00000b  
Technology Ability  
Field  
12:5  
Received Code Word Bit 12:5.  
RO  
00h  
00h  
Remote Fault  
Acknowledge  
Next Page  
13  
14  
15  
Received Code Word Bit 13.  
Received Code Word Bit 14.  
Received Code Word Bit 15.  
RO  
RO  
RO  
0b  
0b  
0b  
0b  
0b  
0b  
1.  
(MODE[3:0] is one of xx00b, 1x01b, 101xb, 1111b) for the 82544GC/EI only.  
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Register Descriptions  
82544GC/EI Only:  
Table 13-23. Link Partner Ability Register (Base Page) Bit  
1
Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
00000b  
SW Rst  
Reserved  
4:0  
Reserved. Should be set to 00000b.  
RO  
00000b  
1b = 10 Base-TX half duplex is  
available.  
0b = 10 Base-TX half duplex is not  
available.  
10BASE-TX Half  
Duplex  
5
6
RO  
RO  
RO  
0b  
0b  
0b  
0b  
0b  
0b  
1b = 10 Base-TX full duplex is available.  
0b = 10 Base-TX full duplex is not  
available.  
10BASE-TX Full  
Duplex  
1b = 100 Base-TX half duplex is  
available.  
0b = 100 Base-TX half duplex is not  
available.  
100BASE-TX Half  
Duplex  
7
8
1b = 100 Base-TX full duplex is  
available.  
0b = 100 Base-TX full duplex is not  
available.  
100BASE-TX Full  
Duplex  
RO  
0b  
0b  
100BASE-T4  
Pause  
9
0b = Not capable of 100BASE-T4.  
RO  
RO  
Always 0b  
1b = Pause operation is available.  
0b = Pause operation is not available.  
10  
0b  
0b  
0b  
0b  
1b = Asymmetric Pause operation is  
available.  
0b = Asymmetric Pause operation is not  
available.  
Asymmetric Pause  
11  
RO  
Reserved  
12  
13  
14  
Reserved. Should be set to 0b.  
Indicates a remote fault.  
RO  
RO  
RO  
0b  
0b  
0b  
0b  
0b  
Remote Fault  
Reserved  
Reserved. Should be set to 0b.  
0b  
0b  
1b = Link partner is Next Pagable.  
0b = Link partner is not Next Pagable.  
Next Page  
15  
RO  
0b  
1.  
(MODE[3:0] is one of 001xb, 0111b).  
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Register Descriptions  
82541xx and 82547GI/EI Only:  
1
Table 13-24. PHY Link Page Ability Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
<00001> = IEEE 802.3  
Other combinations are reserved.  
Unspecified or reserved combinations  
shall not be transmitted.  
Selector Field [4:0]  
4:0  
RO  
N/A  
If field does not match PHY Register 4,  
bits 4:0, the AN process does not  
complete and no HCD is selected.  
1b = Link Partner is 10BASE-T capable.  
0b = Link Partner is not 10BASE-T  
capable.  
10BASE-T  
5
6
RO  
RO  
N/A  
N/A  
1b = Link Partner is 10BASE-T full  
duplex capable.  
0b = Link Partner is not 10BASE-T full  
duplex capable.  
10BASE-T Full  
Duplex  
1b = Link Partner is 100BASE-TX  
capable.  
0b = Link Partner is not 100BASE-TX  
capable.  
100BASE-TX  
7
8
RO  
RO  
N/A  
N/A  
1b = Link Partner is 100BASE-TX full  
duplex capable.  
0b = Link Partner is not 100BASE-TX  
full duplex capable.  
100BASE-TX Full  
Duplex  
1b = Link Partner is 100BASE-T4  
capable.  
0b = Link Partner is not 100BASE-T4  
capable.  
100BASE-T4  
LP Pause  
9
RO  
RO  
N/A  
N/A  
Link Partner uses Pause Operation as  
defined in 802.3x.  
10  
Asymmetric Pause Direction Bit  
1b = Link Partner is capable of  
asymmetric pause.  
LP ASM_DIR  
11  
RO  
N/A  
0b = Link Partner is not capable of  
asymmetric pause.  
Reserved  
12  
13  
Reserved. Should be set to 0b.  
RO  
RO  
0b  
1b = Remote fault.  
0b = No remote fault.  
Remote Fault  
N/A  
1b = Link Partner has received Link  
Code Word from the PHY.  
0b = Link Partner has not received Link  
Code Word from the PHY.  
Acknowledge  
Next Page  
14  
15  
RO  
RO  
N/A  
N/A  
1b = Link Partner has ability to send  
multiple pages.  
0b = Link Partner has no ability to send  
multiple pages.  
1.  
PHY register 8d stores the Auto-Negotiation Link Partner Received Next Pages. PHY register 5d is not used to store Next  
Pages. It contains the information from the last Base Page correctly received.  
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Register Descriptions  
13.4.7.1.7  
Auto-Negotiation Expansion Register  
ANE (06d; R)  
Table 13-25. Auto-Negotiation Expansion Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Link Partner is Auto-Negotiation  
able.  
0b = Link Partner is not Auto-  
Negotiation able.  
Link Partner Auto-  
Negotiation Able  
0
RO  
0b  
0b  
1b = A New Page has been received.  
0b = A New Page has not been  
received.  
RO/  
LH1  
82541xx and 82547GI/EI only:  
If PHY register 16, bit 1 (Alternate NP  
Feature) is set, the Page Received bit  
also clears when mr_page_rx = false or  
transmit_disable = true.  
Page Received  
1
0b  
0b  
0b  
Local Next Page Able  
2
3
4
1b = Local Device is Next Pageable.  
RO  
RO  
1b (82541xx and  
82547GI/EI)  
1b = Link Partner is Next Page able.  
0b = Link Partner is not Next Page able.  
82544GC/EI only:  
Bit 2 = 1 if MODE[3:0] is not 001xb or  
0111b.  
0b  
0b  
Link Partner Next  
Page Able  
MODE  
[3:0]  
MODE[3:0]  
1b = A fault has been detected via the  
Parallel Detection function.  
0b = A fault has not been detected via  
the Parallel Detection function.  
Parallel Detection  
Fault  
RO/  
LH1  
0b  
0b  
82541xx and 82547GI/EI only:  
This bit indicates the status of the Auto-  
Negotiation variable, base page. If flags  
synchronization with the Auto-  
Negotiation state diagram enabling  
detection of interrupted links. This bit is  
only used if PHY register 16, bit 1  
(Alternate NP Feature) is set.  
1b = base_page = true.  
0b = base_page = false.  
Note: This is a reserved bit for all  
remaining Ethernet controllers.  
RO/  
LH1  
Base Page  
Reserved  
5
0b  
0b  
15:6  
0000000000b  
RO  
Always 000h  
1.  
82541xx and 82547GI/EI only.  
NOTE: The ANE Register is not valid until the Auto-Negotiation complete bit in the PHY Status Register  
indicates completion of the Auto-Negotiation process.  
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Register Descriptions  
13.4.7.1.8  
Next Page Transmit Register  
NPT (07d; R/W)  
Table 13-26. Next Page Transmit Register Bit Description  
Field  
Message/  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Transmit Code Word Bit 10:0.  
82541xx and 82547GI/EI only:  
11-bit message code field.  
10:0  
R/W  
001h  
001h  
Unformatted Field  
Transmit Code Word Bit 11.  
82541xx and 82547GI/EI only:  
1b = Previous value of the transmitted  
Link Code Word = logical 0.  
0b = Previous value of the transmitted  
Link Code Word = logical 1.  
Toggle  
11  
RO  
0b  
0b  
0b  
0b  
Transmit Code Word Bit 12.  
82541xx and 82547GI/EI only:  
1b = Complies with message.  
0b = Cannot comply with message.  
Acknowledge 2  
Message Page  
Reserved  
12  
13  
14  
R/W  
R/W  
RO  
Transmit Code Word Bit 13.  
82541xx and 82547GI/EI only:  
1b = Message page.  
1b  
1b  
0b1  
0b1  
0b = Unformatted page.  
Transmit Code Word Bit 14.  
82541xx and 82547GI/EI only:  
Always read as 0b. Write to 0b for  
normal operation.  
0b  
0b  
0b  
0b  
Transmit Code Word Bit 15.  
A write to the NPT Register implicitly  
sets a variable in the Auto-Negotiation  
state machine.  
Next Page  
15  
R/W  
82541xx and 82547GI/EI only:  
1b = Additional next pages follow.  
0b = Last page.  
1.  
82541xx and 82547GI/EI only.  
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Register Descriptions  
13.4.7.1.9  
Link Partner Next Page Register  
LPN (08d; R)  
Table 13-27. Link Partner Next Page Register Bit Description  
Bit(s)  
Field  
Description  
Mode  
HW Rst  
SW Rst  
Received Code Word Bit 10:0.  
82541xx and 82547GI/EI only:  
11-bit message code field.  
Message/  
Unformatted Field  
10:0  
RO  
000h  
000h  
Received Code Word Bit 11.  
82541xx and 82547GI/EI only:  
1b = Previous value of the transmitted  
Link Code Word = a logic 0.  
0b = Previous value of the transmitted  
Link Code Word = a logic 1.  
11  
Toggle  
RO  
RO  
RO  
RO  
RO  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
Received Code Word Bit 12.  
82541xx and 82547GI/EI only:  
1b = Link Partner complies with the  
message.  
0b = Link Partner cannot comply with  
the message.  
12  
13  
14  
15  
Acknowledge 2  
Message Page  
Acknowledge  
Next Page  
Received Code Word Bit 13.  
82541xx and 82547GI/EI only:  
1b = Page sent by the Link Partner is a  
Message Page.  
0b = Page sent by the Link Partner is an  
Unformatted Page.  
Received Code Word Bit 14.  
82541xx and 82547GI/EI only:  
1b = Link Partner has received Link  
Code Word from the PHY.  
0b = Link Partner has not received Link  
Code Word from the PHY.  
Received Code Word Bit 15.  
82541xx and 82547GI/EI only:  
1b = Link Partner has additional next  
pages to send.  
0b = Link Partner has no additional next  
pages to send.  
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Register Descriptions  
13.4.7.1.10 1000BASE-T Control Register  
GCON (09d; R/W)  
Table 13-28. 1000BASE-T Control Register Bit Description  
Bit(s)  
7:0  
Field  
Reserved  
Description  
Mode  
HW Rst  
0b  
SW Rst  
Reserved. Should be set to 00000000b. R/W  
0b  
1b = Advertise.  
0b = Not advertised.  
82544GC/EI only:  
R/W  
0b  
ANEG[2]  
Retain  
1000BASE-T Half  
Duplex  
Bit 8 = ANEG[2].  
8
82541xx and 82547GI/EI only:  
1b = DTE is 1000BASE-T capable.  
0b = DTE is not 1000BASE-T capable.  
This bit is used by Smart Negotiation.  
1b = Advertise.  
0b = Not advertised.  
82544GC/EI only:  
Bit 9 = ANEG[3].  
R/W  
1b  
ANEG[3]  
Retain  
1000BASE-T Full  
Duplex  
82541xx and 82547GI/EI only:  
1b = DTE is 1000BASE-T full duplex  
capable.  
9
0b = DTE is not 1000BASE-T full duplex  
capable. This bit is used by Smart  
Negotiation (see Note 3).  
1b = Prefer multi-port device  
(MASTER).  
0b = Prefer single port device (SLAVE)1.  
82544GC/EI only:  
R/W  
R/W  
1b2  
ANEG[0]  
Retain  
Retain  
10  
11  
Port Type  
Bit 10 =!ANEG[0].  
Bit 10 is ignored if bit 12 = 1b.  
1b = Manual configure as MASTER3.  
0b = Manual configure as SLAVE3.  
82544GC/EI only:  
MASTER/SLAVE  
Configuration Value  
1b2  
ANEG[0]  
Bit 11 =!ANEG[0].  
Bit 11 is ignored if bit 12 = 0b.  
1b = Manual MASTER/SLAVE  
configuration.  
MASTER/SLAVE  
0b = Automatic MASTER/SLAVE  
R/W  
1b2  
ANEG[1]  
Retain  
12  
Manual Configuration  
Enable  
configuration.  
82544GC/EI only:  
Bit 12 =!ANEG[1].  
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Register Descriptions  
Table 13-28. 1000BASE-T Control Register Bit Description  
Bit(s)  
Field  
Description  
Mode  
HW Rst  
SW Rst  
000b = Normal Mode.  
001b = Test Mode 1 - Transmit  
Waveform Test.  
010b = Test Mode 2 - Transmit Jitter  
Test (MASTER mode).  
15:13  
Test mode  
R/W  
000b  
000b  
011b = Test Mode 3 - Transmit Jitter  
Test (SLAVE mode).  
100b = Test Mode 4 - Transmit  
Distortion Test.  
101b, 110b, 111b = Reserved.  
1.  
2.  
3.  
For the 82541xx and 82547GI/EI, only when PHY register 9, bit 12 is set to a logical 0.  
0b for the 82541xx and 82547GI/EI only  
For the 82541xx and 82547GI/EI, only when PHY register 9, bit 12 is set to a logical 1.  
NOTES:  
1. Values programmed in bits 12:8 of the 1000BASE-T Control Register have no effect unless Auto-Negotiation  
is restarted (PHY Control Register, bit 9) or the link goes down. These bits can also be overridden by the PHY  
Control Register.  
2. The symbol “!” is equivalent to logical “not.”  
3. For the 82541xx and 82547GI/EI, the default for bit 9 is affected by configuration bits in the EEPROM. If  
EEPROM ANI1000DIS is asserted, then the default is set to 0b. If EEPROM ADV10LU is asserted, then the  
default is set to 0b.  
13.4.7.1.11 1000BASE-T Status Register  
GSTATUS (10d; R)  
Table 14-29. 1000BASE-T Status Register Bit Description  
Field  
Idle Error Count  
Reserved  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Idle Error Counter.  
The counter stops at 1111b 1111b and  
does not roll over.  
RO,  
SC  
0000b  
0000b  
0000b  
7:0  
0000b  
00b  
9:8  
10  
Reserved. Should be set to 00b  
RO  
00b  
1b = Link Partner is capable of  
1000BASE-T half duplex.  
0b = Link Partner is not capable of  
1000BASE-T half duplex.  
Values in bits 11:10 are not valid until  
the ANE Register Page Received bit  
equals 1b.  
Link Partner  
1000BASE-T  
Half Duplex  
Capability  
RO  
0b  
0b  
1b = Link Partner is capable of  
1000BASE-T full duplex.  
Link Partner  
1000BASE-T  
Full Duplex Capability  
0b = Link Partner is not capable of  
1000BASE-T full duplex.  
Values in bits 11:10 are not valid until  
the ANE Register Page Received bit  
equals 1b.  
11  
12  
RO  
RO  
0b  
0b  
0b  
0b  
1b = Remote Receiver OK.  
0 b = Remote Receiver Not OK.  
Remote Receiver  
Status  
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Register Descriptions  
Table 14-29. 1000BASE-T Status Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Local Receiver OK.  
0b = Local Receiver Not OK.  
Local Receiver Status 13  
RO  
0b  
0b  
1b = Local PHY configuration resolved  
to MASTER.  
0b = Local PHY configuration resolved  
to SLAVE.  
MASTER/SLAVE  
Configuration  
Resolution  
14  
15  
RO  
0b  
0b  
0b  
0b  
1b = MASTER/SLAVE configuration  
fault detected.  
0b = No MASTER/SLAVE configuration  
fault detected.  
RO,  
LH,  
SC  
MASTER/SLAVE  
Configuration Fault  
13.4.7.1.12 Extended PHY Status Register  
EPSTATUS (15d; R)  
Table 13-30. Extended PHY Status Register Bit Description  
Field  
Reserved  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Reserved. Should be set to  
000000000000b.  
11:0  
RO  
000h  
000h  
1b = 1000BASE-T half duplex capable.  
0b = not 1000BASE-T half duplex  
capable.  
Note: 1000Mb-Half duplex is NOT  
supported.  
1000BASE-T Half  
Duplex  
12  
13  
14  
15  
RO  
RO  
RO  
RO  
1b1  
1b1  
0b1  
0b1  
1b1  
1b1  
0b1  
0b1  
1b = 1000BASE-T full duplex capable.  
0b = Not 1000BASE-T full duplex  
capable.  
1000BASE-T Full  
Duplex  
1b =1000BASE-X half duplex capable.  
0b = Not 1000BASE-X half duplex  
capable.  
Note: 1000Mb-Half Duplex is NOT  
supported.  
1000BASE-X Half  
Duplex  
1b =1000BASE-X full duplex capable.  
0b = Not 1000BASE-X full duplex  
capable.  
1000BASE-X Full  
Duplex  
1.  
MODE[3:0] 82544GC/EI only.  
NOTES:  
1. 1000BASE-X Half Duplex only applicable to the 82544GC/EI.  
2. Bit 12 = bit 13 = 1b if MODE[3:0] does not = 001xb or 0111b.  
3. Bit 14 = bit 15 = 1b if MODE[3:0] = 001xb or 0111b.  
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Register Descriptions  
13.4.7.1.13 PHY Specific Control Register  
PSCON (16d; R/W)  
Table 13-31. PHY Specific Control Register Bit Description  
Description  
1000BASE-T 10/100BASE-T  
Field  
Bit(s)  
Mode  
HW Rst  
SW Rst  
1b = Disable jabber function.  
0b = Enable jabber function.  
Disable Jabber  
0
R/W  
0b  
Retain  
Jabber has effect only in 10BASE-T half  
duplex mode.  
1b = Polarity Reversal Disabled.  
0b = Polarity Reversal Enabled.  
Polarity Reversal  
SQE Test  
1
2
R/W  
R/W  
0b  
0b  
Retain  
Retain  
If polarity is disabled, then the polarity is  
forced to be normal in 10BASE-T.  
1b = SQE test enabled.  
0b = SQE test disabled.  
Jabber has effect only in 10BASE-T half  
duplex mode.  
1b = Always power up.  
0b = Can power down.  
This bit determines whether the MAC  
interface powers down when register  
PHY Control Register bit 11 is used to  
power down the Ethernet controller or  
when the PHY enters the energy detect  
state.  
MAC Interface Power  
Down  
3
4
R/W  
R/W  
1b  
Update  
Update  
1b = 125CLK Low.  
0b = 125CLK Toggling.  
Bit 4 = ENA_XC.  
Disable 125CLK1  
Reserved  
DIS_  
125CLK1  
This bit is reserved for all Ethernet  
controllers except the 82544GC/EI.  
Should be set to 0b.  
0b  
00b = Manual MDI configuration.  
01b = Manual MDI-X configuration.  
10b = Reserved.  
11b = Enable automatic crossover for all  
modes.  
MDI Crossover Mode 6:5  
R/W  
11b  
Update  
82544GC/EI only:  
Bit 6 = DIS_125.  
Bit 5 = ENA_XC.  
1b = Lower 10BASE-T receive  
threshold.  
0b = Normal 10BASE-T receive  
threshold.  
Enable Extended  
Distance  
7
R/W  
0b  
Retain  
When a cable longer than 100 m is  
used, the 10BASE-T receive threshold  
must be lowered in order to detect  
incoming signals.  
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Register Descriptions  
Table 13-31. PHY Specific Control Register Bit Description  
Description  
1000BASE-T 10/100BASE-T  
Field  
Bit(s)  
Mode  
HW Rst  
SW Rst  
Energy Detect.  
0xb = Off.  
Energy Detect  
9:8  
R/W  
0b  
Retain  
10b = Sense only on receive.  
11b = Sense and periodically transmit  
NLP.  
1b = Force link good.  
0 b = Normal operation.  
If link is forced to be good, the link state  
machine is bypassed and the link is  
always up. In 1000BASE-T mode this  
has no effect.  
Force Link Good  
10  
11  
R/W  
R/W  
0b  
0b  
Retain  
Retain  
1b = Assert on transmit.  
Assert CRS on  
Transmit  
0b = Never assert on transmit.  
This bit has no effect in full duplex.  
00b = 16 Bits  
01b = 24 Bits  
10b = 32 Bits  
11b = 40 Bits  
00b = 8 Bits  
01b = 12 Bits  
10b = 16 Bits  
11b = 20 Bits  
Receive FIFO depth  
13:12  
R/W  
R/W  
00b  
00b  
Retain  
Retain  
Receive FIFO is enabled in internal  
SerDes mode2 or serial interface mode.  
00b = 16 Bits  
01b = 24 Bits  
10b = 32 Bits  
11b = 40 Bits  
00 b= 8 Bits  
01b = 12 Bits  
10b = 16 Bits  
11b = 20 Bits  
Transmit FIFO depth 15:14  
Transmit FIFO is enabled in 1000BASE-  
T mode or serial interface mode.  
1.  
2.  
82544GC/EI only.  
TBI Mode for the 82544GC/EI.  
PHY Port Configuration Register (82541xx and 82547GI/EI Only)  
PPCONF (16d; R/W)  
Table 13-32. PHY Port Configuration Register Bit Description  
Field  
Reserved  
Bit(s)  
Description  
Mode  
HW Rst  
0b  
SW Rst  
0
Write to 0b for normal operation.  
R/W  
0b  
1b = Enable alternate Auto-Negotiate  
next page feature.  
0b = Disable alternate Auto-Negotiate  
next page feature.  
Alternate NP Feature  
Reserved  
1
R/W  
R/W  
0b  
0b  
0b  
0b  
If polarity is disabled, then the polarity is  
forced to be normal in 10BASE-T.  
3:2  
Write to 0b for normal operation.  
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Register Descriptions  
Table 13-32. PHY Port Configuration Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Auto_MDIX Parallel Detect Bypass.  
Bypasses the fix to IEEE auto-MDIX  
algorithm for the case where the PHY is  
in forced-speed mode and the link  
partner is auto-negotiating.  
1b = Strict 802.3 Auto-MDIX algorithm.  
Auto MDIX Parallel  
Detect Bypass  
4
R/W  
0b  
0b  
0b = Auto-MDIX algorithm handles  
Auto-Negotiation disabled modes. This  
is accomplished by lengthening the  
auto-MDIX switch timer before  
attempting to swap pairs on the first time  
out.  
Preamble Enable  
0b = Set RX_DV high coincident with  
SFD.  
PRE_EN  
5
R/W  
1b  
1b  
1b = Set RX_DV high and RXD =  
preamble (after CRS is asserted).  
Reserved  
6
7
Write to 0b for normal operation.  
R/W  
R/W  
0b  
0b  
0b  
1b = Smart Speed selection enabled.  
0b = Smart Speed selection disabled.  
Smart Speed  
0b1  
1b = Disable TP loopback during half-  
duplex operation.  
TP Loopback  
(10BASE-T)  
8
R/W  
1b  
1b  
0b = Normal operation.  
Reserved  
9
Write to 0b for normal operation.  
R/W  
R/W  
0b  
0b  
0b  
0b  
1b = Disable jabber.  
0b = Enable jabber.  
Jabber (10BASE-T)  
10  
1b = Bypass4B5B encoder and  
decoder.  
Bypass 4B5B  
(100BASE-TX)  
11  
R/W  
0b  
0b  
0b = Normal operation.  
1b = Bypass scrambler and  
descrambler.  
Bypass Scramble  
(100BASE-TX)  
12  
13  
R/W  
R/W  
0b  
0b  
0b  
0b  
0b = Normal operation.  
1b = Disable twisted-pair transmitter.  
0b = Normal operation.  
Transmit Disable  
1b = Force link pass  
0b = Normal operation  
For 10BASE-T, this bit forces the link  
signals to be active. In 100BASE-T  
mode, setting this bit should force the  
Link Monitor into it’s LINKGOOD state.  
For Gigabit operation, this merely  
bypasses Auto-Negotiation—the link  
signals still correctly indicate the  
appropriate status.  
Link Disable  
Reserved  
14  
R/W  
R/W  
0b  
0b  
0b  
0b  
Always read as 0b. Write 0b for normal  
operation.  
16:15  
1.  
The default for this bit is determined by EEPROM bit SSPEED.  
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Register Descriptions  
13.4.7.1.14 PHY Specific Status Register  
PSSTAT (17d; R)  
Table 13-33. PHY Specific Status Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Jabber.  
0 = No jabber.  
Jabber (real time)  
0
RO  
0b  
Retain  
1b = Reversed.  
0b = Normal.  
Polarity (real time)  
1
2
RO  
RO  
0b  
0b  
0b  
0b  
1b = Receive pause enabled.  
0b = Receive pause disabled.  
The Receive Pause Enable bit is valid  
only after the Speed and Duplex  
Resolved bit (11) is set. This occurs  
when Auto-Negotiation is completed or  
Auto-Negotiation is disabled.  
This is a reflection of the MAC pause  
resolution.  
Receive Pause  
Enable  
1b = Transmit pause enabled.  
0b = Transmit pause disabled.  
The Transmit Pause Enable bit is valid  
only after the Speed and Duplex  
Resolved bit (11) is set. This occurs  
when Auto-Negotiation is completed or  
Auto-Negotiation is disabled.  
Transmit Pause  
Enabled  
3
RO  
0b  
0b  
0b = Active  
1b = Sleep  
Energy Detect Status  
Downshift Status  
4
5
RO  
RO  
0b  
0b  
0b  
0b  
1b = Downshift.  
0b = No Downshift.  
1b = MDI-X.  
0b = MDI.  
The MDI Crossover Status bit is valid  
only after the Speed and Duplex  
Resolved bit (11) is set. This occurs  
when Auto-Negotiation is completed or  
Auto-Negotiation is disabled.  
MDI Crossover  
Status  
6
RO  
0b  
0b  
000b = < 50 m.  
001b = 50 80 m.  
010b = 80 110 m.  
011b = 110 140 m.  
100b = >140 m.  
Cable length measurement is only a  
rough estimate. The actual value  
depends on the attenuation of the cable,  
output levels of the remote transceiver,  
connector impedance, etc.  
Cable Length  
(100/1000 modes  
only)  
9:7  
10  
RO  
RO  
000b  
000b  
1b = Link up.  
0b = Link down.  
Link (real time)  
0b  
0b  
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Register Descriptions  
Table 13-33. PHY Specific Status Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Resolved.  
0b = Not resolved.  
Speed, Duplex, MDI Crossover Status,  
Transmit Pause Enable, and Receive  
Pause Enable bits are valid only after  
the Speed and Duplex Resolved bit (11)  
is set. This occurs when Auto-  
Negotiation is completed or Auto-  
Negotiation is disabled.  
Speed and Duplex  
Resolved  
11  
RO  
0b  
0b  
1b = Page received.  
0b = Page not received.  
RO,  
LH  
Page Received  
Duplex  
12  
13  
0b  
0b  
0b  
1b = Full duplex.  
0b = Half duplex.  
The Duplex bit is valid only after the  
Speed and Duplex Resolved bit (11) is  
set. This occurs when Auto-Negotiation  
is completed or Auto-Negotiation is  
disabled.  
RO  
Retain  
11b = Reserved.  
10b = 1000 Mb/s.  
01b = 100 Mb/s.  
00b = 10 Mb/s.  
Speed  
15:14  
RO  
00b  
Retain  
The Speed bit is valid only after the  
Speed and Duplex Resolved bit (11) is  
set. This occurs when Auto-Negotiation  
is completed or Auto-Negotiation is  
disabled.  
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Register Descriptions  
PHY Port Status 1 Register (82541xx and 82547GI/EI Only)  
PPSTAT (17d; R)  
Table 13-34. PHY Status 1 Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Status bit indicating the Auto-  
Negotiation Link Fail Inhibit Timer has  
expired. This indicates that the Auto-  
Negotiation process completed page  
exchanges but was unable to bring up  
the selected MAU’s link.  
1b = Auto-Negotiation has aborted Link  
establishment following normal page  
exchange.  
0b = Auto-Negotiation has either  
completed normally, or is still in  
progress.  
RO/  
LH/  
SC  
LFIT Indicator  
0
0b  
0b  
This bit is cleared when read or when  
one of the following occurs:  
Link comes up (PHY register 17, bit 10 =  
1b).  
Auto-Negotiation is disabled (PHY  
register 0, bit 12 = 0b).  
Auto-Negotiation is restarted (PHY  
register 0, bit 9 = 1b).  
1b = 10BASE-T polarity is reversed.  
0b = 10BASE-T polarity is normal.  
Polarity Status  
Reserved  
1
RO  
RO  
RO  
0b  
0b  
0b  
0b  
0b  
0b  
8:2  
9
Write to 0b for normal operation.  
1b = Full duplex.  
0b = Half duplex.  
Duplex Mode  
Indicates the current status of the link.  
Differs from PHY register 1, bit 2 in that  
this bit changes anytime the link status  
changes. PHY register 1, bit 2 latches  
low and stays low until read regardless  
of link status.  
Link  
10  
RO  
0b  
0b  
1b = Link is currently up.  
0b = Link is currently down.  
Status indicator of the current MDI/MDI-  
X state of the twisted pair interface. This  
status bit is valid regardless of the MAU  
selected.  
1b = PHY has selected MDI-X (crossed  
over).  
MDI-X Status  
11  
12  
RO  
RO  
0b  
0b  
0b  
0b  
0b = PHY has selected MDI (NOT  
crossed over).  
1b = PHY currently receiving a packet.  
0b = PHY receiver is IDLE.  
Receive Status  
When in loopback, this bit reads as 0b.  
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Register Descriptions  
Table 13-34. PHY Status 1 Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = PHY currently transmitting a  
packet.  
Transmit Status  
13  
RO  
0b  
0b  
0b = PHY transmitter is IDLE.  
When in loopback, this bit reads as 0b.  
00b = Reserved.  
01b = PHY operating in 10BASE-T  
mode.  
Data Rate  
15:14  
RO  
0b  
0b  
10b = PHY operating in 100BASE-TX  
mode.  
11b = PHY operating in 1000BASE-T  
mode.  
13.4.7.1.15 PHY Interrupt Enable Register  
PINTE (18d; R/W)  
Table 13-35. PHY Interrupt Enable Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Interrupt enable.  
0b = Interrupt disable.  
Jabber Interrupt  
Enable  
0
R/W  
0b  
Retain  
Polarity Changed  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
1
R/W  
R/W  
R/W  
0b  
0b  
0b  
Retain  
Retain  
Retain  
Reserved  
3:2  
4
Always write 00b.  
1b = Interrupt enable.  
0b = Interrupt disable.  
Energy Detect  
1b = Interrupt enable.  
0b = Interrupt disable.  
Downshift Interrupt  
Enable  
5
6
R/W  
R/W  
0b  
0b  
Retain  
Retain  
MDI Crossover  
Changed  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
FIFO Over/Underflow  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
7
R/W  
R/W  
R/W  
R/W  
0b  
0b  
0b  
0b  
Retain  
Retain  
Retain  
Retain  
1b = Interrupt enable.  
0 b= Interrupt disable.  
False Carrier  
Interrupt Enable  
8
Symbol Error  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
9
Link Status Changed  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
10  
Auto-Negotiation  
Completed  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
11  
R/W  
0b  
Retain  
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Register Descriptions  
Table 13-35. PHY Interrupt Enable Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
0b  
SW Rst  
Page Received  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
12  
R/W  
Retain  
Duplex Changed  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
13  
14  
R/W  
R/W  
0b  
0b  
Retain  
Retain  
Speed Changed  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
Auto-Negotiation  
Error  
Interrupt Enable  
1b = Interrupt enable.  
0b = Interrupt disable.  
15  
R/W  
0b  
Retain  
PHY Port Control Register (82541xx and 82547GI/EI Only)  
PPCONT (18d; R/W)  
Table 13-36. PHY Port Control Register Bit Description  
Field  
Reserved  
Bit(s)  
3:0  
Description  
Mode  
HW Rst  
0b  
SW Rst  
Always read as 0b. Write to 0b for  
normal operation.  
R/W  
0b  
0b  
TP Loopback  
4
Allow gigabit loopback on twisted pairs. R/W  
0b  
82541EI/82547GI (B0 stepping):  
Reserved, write to 0b.  
82541/GI/ER and 82547GI (B1  
stepping): Fast 1000 Mb to 100 Mb  
downshift enable.  
Fast Downshift  
Enable  
5
R/W  
0b  
0b  
0b = Downshift after 16 seconds.  
1b = Downshift after 10 seconds.  
Always read as 0b. Write to 0b for  
normal operation.  
Reserved  
8:6  
9
R/W  
R/W  
0b  
0b  
0b  
1b = Detect and correct for non-  
compliant scrambler.  
Non-Compliant  
Scrambler  
Compensation  
0b1  
0b = Detect and report non-compliant  
scrambler.  
1b = Extend CRS to cover GMII latency  
and RX_DV.  
TEN_CRS_Select  
Reserved  
10  
11  
R/W  
1b  
1b  
1b  
1b  
0b = Do not extend CRS (RX_DV can  
continue past CRS).  
Always write as 1b for normal operation. R/W  
Auto-MDI-X algorithm enable.  
1b = Enable Auto-MDI-X mode.  
0b = Disable Auto-MDI-X mode (manual  
mode).  
Auto-MDI-X  
12  
R/W  
1b  
1b  
Note: When forcing speed to 10Base-T  
or 100Base-T, use manual mode. Clear  
the bit and set PHY register 18, bit 13  
according to the required MDI-X mode.  
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Register Descriptions  
Table 13-36. PHY Port Control Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Force MDI-X mode. Valid only when  
operating in manual mode. (PHY  
register 18, bit 12 = 0b.  
MDI-X Mode  
Reserved  
13  
R/W  
0b  
0b  
1b = MDI-X (cross over).  
0b = MDI (no cross over).  
Always read as 0b. Write to 0b for  
normal operation.  
14  
R/W  
0b  
0b  
This configuration bit is used to enable  
the Ethernet controller to drive its  
differential transmit clock out through  
the appropriate Analog Test (ATEST+/-)  
output pads. This feature is required in  
order to demonstrate conformance to  
the IEEE Clause 40 jitter specification.  
When high, it sends Jitter Test Clock  
out.  
Jitter Test Clock  
15  
R/W  
0b  
0b  
This bit works in conjunction with  
internal PHY register 18, bit 15. In order  
to have the clock probed out, it is  
required to perform the following write  
sequence:  
PHY register 18, bit15 = 1b  
PHY register 31 = 4000h (page select)  
PHY register 17 = 0080h  
PHY register 31 = 0000h (page select)  
1.  
The default for this bit is determined by EEPROM configuration bits. If EEPROM bit NCSCRAMB is asserted, then the  
default is set to 1b.  
13.4.7.1.16 PHY Interrupt Status Register  
PINTS (19d; R)  
Table 13-37. PHY Interrupt Status Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
0b  
SW Rst  
1b = Jabber.  
RO,  
LH  
Jabber  
0
0b  
0b = No jabber.  
1b = Polarity Changed.  
0b = Polarity not changed.  
RO,  
LH  
Polarity Changed  
Reserved  
1
0b  
0b  
3:2  
4
Reserved. Should be set to 00b.  
RO  
Always 00b  
0b  
1b = Energy Detect state changed  
0b = No state change detected  
RO,  
LH  
Energy Detect  
0b  
0b  
0b  
1b = Downshift detected.  
0b = No down shift.  
RO,  
LH  
Downshift Detected  
5
6
0b  
0b  
1b = Crossover changed.  
0b = Crossover not changed.  
MDI Crossover  
Changed  
RO,  
LH  
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Register Descriptions  
Table 13-37. PHY Interrupt Status Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
0b  
SW Rst  
1b = Over/Underflow Error.  
0b = No FIFO Error.  
RO,  
LH  
FIFO Over/Underflow  
7
0b  
1b = False carrier.  
0b = No false carrier.  
RO,  
LH  
False Carrier  
Symbol Error  
8
9
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
1b = Symbol error.  
0b = No symbol error.  
RO,  
LH  
1b = Link status changed.  
0b = Link status not changed.  
RO,  
LH  
Link Status Changed 10  
Auto-Negotiation  
11  
1b = Auto-Negotiation completed.  
0b = Auto-Negotiation not completed.  
RO,  
LH  
Completed  
1b = Page received.  
0b = Page not received.  
RO,  
LH  
Page Received  
Duplex Changed  
Speed Changed  
12  
13  
14  
1b = Duplex changed.  
0b = Duplex not changed.  
RO,  
LH  
1b = Speed changed.  
0b = Speed not changed.  
RO,  
LH  
1b = Auto-Negotiation Error.  
0b = No Auto-Negotiation Error.  
An error occurs if MASTER/SLAVE  
does not resolve, parallel detect fault,  
no common HCD, or link does not  
validate after negotiation has  
completed.  
Auto-Negotiation  
Error  
RO,  
LH  
15  
0b  
0b  
PHY Link Health Register (82541xx and 82547GI/EI Only)  
PLINK (19d; R)  
Table 13-38. PHY Link Health Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
0b  
SW Rst  
The channel A DSP had converged to  
incoming data.  
Valid Channel A  
0
RO  
0b  
The channel B DSP had converged to  
incoming data.  
Valid Channel B  
Valid Channel C  
Valid Channel D  
1
2
3
RO  
RO  
RO  
0b  
0b  
0b  
0b  
0b  
0b  
The channel C DSP had converged to  
incoming data.  
The channel D DSP had converged to  
incoming data.  
Auto-Negotiation  
Active  
Auto-Negotiate is actively deciding  
HCD.  
4
5
RO  
RO  
0b  
0b  
0b  
0b  
Reserved  
Always read as 0b.  
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Register Descriptions  
Table 13-38. PHY Link Health Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Auto-Negotiate Fault: This is the logical  
OR of PHY register 1, bit 4, PHY  
register 6, bit 4, and PHY register 10, bit  
15.  
Auto-Negotiation  
Fault  
6
RO  
RO  
0b  
0b  
0b  
Reserved  
7
8
Always read as 0b.  
0b  
0b  
Mode:  
10: 10 Mbps polarity error.  
100: Symbol error.  
1000: Gig idle error.  
Data Err[0]  
LH  
0b  
0b  
Mode:  
10: Reserved.  
RO/  
LH  
Data Err[1]  
9
0b  
100: Scrambler unlocked.  
1000: Local receiver not OK.  
RO/  
LH  
Count Overflow  
10  
11  
The idle error counter has overflowed.  
0b  
0b  
0b  
0b  
Gig has detected a remote receiver  
status error. This is a latched high  
version of PHY register 10, bit 12.  
Gigabit Rem Rcvr  
NOK  
RO/  
LH  
Gig has resolved to master. This is a  
duplicate of PHY register 10, bit 14.  
Programmers must read PHY register  
10, bit 14 to clear this bit.  
Gigabit Master  
Resolution  
12  
13  
RO  
RO  
0b  
0b  
0b  
0b  
A fault has occurred with the gig master/  
slave resolution process. This is a copy  
of PHY register 10, bit 15.  
Gigabit Master Fault  
Programmers must read PHY register  
10, bit 15 to clear this bit.  
1b indicates that the PHY has detected  
gigabit connection errors that are most  
likely due to a non-IEEE compliant  
scrambler in the link partner.  
Gigabit Scrambler  
Error  
0b = Normal scrambled data.  
14  
15  
RO  
0b  
0b  
0b  
0b  
Definition is: If an_enable is true and in  
Gigabit mode, on the rising edge of  
internal signal link_fail_inibit  
timer_done, the dsp_lock is true but  
loc_rcvr_OK is false.  
Smart Speed has downgraded the link  
speed from the maximum advertised.  
RO/  
LH  
SS Downgrade  
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Register Descriptions  
1
13.4.7.1.17 Extended PHY Specific Control Register 1  
EPSCON1 (20d; R/W)  
1
Table 13-39. Extended PHY Specific Control 1 Bit Description  
Field  
Reserved  
Bit(s)  
1:0  
Description  
Mode  
R/W  
HW Rst  
00b  
SW Rst  
Retain  
0
00b  
0b  
Reserved  
3
R/W  
0b  
Reserved. Should be set to 0b.  
Changes to this bit are disruptive to the  
normal operation; any change to this  
register must be followed by software  
reset to take effect.  
Reserved  
6:4  
R/W  
R/W  
110b  
Update  
Update  
Reserved. Should be set to 0b.  
Changes to this bit are disruptive to the  
normal operation; any change to this  
register must be followed by software  
reset to take effect.  
Reserved  
7
0b  
00b = disable. (10/100 downshift)  
01b = 1x.  
10b = 2x.  
11b = 3x.  
Slave downshift  
counter  
Changes to this bit are disruptive to the  
normal operation; any change to this  
register must be followed by software  
reset to take effect.  
9:8  
R/W  
01b  
Update  
Bits 11:10 have no effect unless bits 1:0  
are set to their default values.  
00b = 1x.  
01b = 2x.  
10b = 3x.  
11b = 4x.  
Number of times that the PHY attempts  
to achieve gigabit link before  
downshifting to the next speed in Master  
Mode.  
Master downshift  
counter  
11:10  
R/W  
11b  
Update  
Changes to this bit are disruptive to the  
normal operation; any change to this  
register must be followed by software  
reset to take effect.  
Bits 11:10 have no effect unless bits 1:0  
are set to their default values.  
Reserved  
Reserved  
Reserved  
Reserved  
12  
13  
14  
15  
Reserved. Should be set to 0b.  
Reserved. Should be set to 0b.  
Reserved. Should be set to 0b.  
Reserved. Should be set to 0b.  
R/W  
R/W  
R/W  
R/W  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
1. Extended PHY Specific Control Register - EPSCON for the 82544GC/EI only.  
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Register Descriptions  
GMII FIFO Register (82541xx and 82547GI/EI Only)  
PFIFO (20d; R/W)  
Table 13-40. GMII FIFO Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
An unsigned integer that stipulates the  
number of write clocks to delay the read  
controller after internal GMII’s tx_en is  
Buffer Size  
3:0  
first asserted. This “buffer” protects from R/W  
underflow at the expense of latency.  
The maximum value that can be set is  
13d or Dh.  
0101b  
0101b  
When set, the PHY advertises higher  
speed than 10Base-T after reconnect of  
the cable, even if the software  
advertised only 10Base-T speed.  
Enable Speed-Up  
Upon Cable  
Reconnect  
4
R/W  
Note 2  
Note 2  
When set, the PHY optimizes the power  
consumption when the cable is  
Power Down On Link  
Disconnect  
disconnected. The PHY gets back to  
normal operation reconnect of the cable,  
supporting Auto-Negotiation and parallel  
detection.  
5
R/W  
Note 1  
00b  
Note 1  
00b  
Always read as 0b. Write to 0b for  
R/W  
Reserved  
7:6  
normal operation.  
00b, 01b: Enable the output data bus  
from GMII FIFO to transmitters, drives  
zeros on the output loop-back bus from  
GMII FIFO to external application and to  
DSP RX-FIFOs in test mode.  
10b: Drive zeros on output bus from  
GMII FIFO to transmitters, enable data  
on the output loop-back bus from GMII  
FIFO to external application and to DSP  
RX-FIFOs in test mode.  
FIFO Out Steering  
9:8  
R/W  
00b  
00b  
11b: Enable the output data bus from  
GMII FIFO to both transmitters and  
loop-back bus.  
When set, disables the addition of  
Disable Error Out  
Reserved  
10  
under/overflow errors to the output data R/W  
stream on internal GMII’s tx_error.  
0b  
0b  
0b  
0b  
Always read as 0b. Write to 0b for  
R/W  
13:11  
normal operation.  
Status bit set when read clock that is  
faster than internal GMII’s gtx_clk  
empties the FIFO mid packet. Increase  
the buffer size.  
RO/  
LH  
FIFO Overflow  
14  
15  
0b  
0b  
0b  
0b  
Status bit set when read clock that is  
slower than internal GMII’s gtx_clk has  
allowed the FIFO to fill to capacity mid  
packet. Decrease buffer size.  
RO/  
LH  
FIFO Underflow  
NOTES:  
1. The default is determined by EEPROM bit SPD_EN.  
2. The default is determined by EEPROM bit ADV10LU.  
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13.4.7.1.18 PHY Receive Error Counter  
PREC (21d; R)  
Table 13-41. PHY Receive Error Counter Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW RST  
Receive Error Count  
15:0  
Error Count.  
RO,SC 0000h  
0000h  
NOTE: The counter stops at FFFFh and does not roll over.  
PHY Channel Quality Register (82541xx and 82547GI/EI Only)  
PCHAN (21d; R)  
Table 13-42. PHY Channel Quality Register Bit Description  
Field  
Bit(s)  
3:0  
Description  
Mode  
HW Rst  
0b  
SW Rst  
The converged mean square error for  
Channel D.  
MSE D  
MSE C  
MSE B  
RO  
0b  
The converged mean square error for  
Channel C.  
7:4  
RO  
RO  
0b  
0b  
0b  
0b  
The converged mean square error for  
Channel B.  
11:8  
The converged mean square error for  
Channel A. This field is only meaningful  
in gigabit, or in 100BASE-TX if this is  
the receive pair.  
MSE A  
15:12  
RO  
0b  
0b  
Use of this field is complex and needs  
interpretation based on the chosen  
threshold value.  
13.4.7.1.19 SPEED_TEN_LED and LINK_ACT_LED Control (82541xx and 82547GI/EI Only)  
(23d; R/W)  
Table 13-43. SPEED_TEN_LED and LINK_ACT_LED Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
MUX the designated input to  
SPEED_TEN_LED.  
LED Source Select  
3:0  
R/W  
0000b  
0000b  
Disable the SPEED_TEN_LED Blink  
Logic.  
0b = Enable logic.  
1b = Disable logic.  
LED Blink Disable  
4
R/W  
0b  
0b  
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Register Descriptions  
Table 13-43. SPEED_TEN_LED and LINK_ACT_LED Bit Description  
Disable the SPEED_TEN_LED  
Extension Logic.  
0b = Enable logic.  
1b = Disable logic.  
LED Stretch Disable  
5
R/W  
1b  
1b  
Note: Only when both the stretch and  
blink are disabled the input bypasses  
the blink logic and is muxed out with no  
sampling (only combinational logic).  
Mux the designated input to  
LED_ACT_LED.  
LED Source Select  
LED Blink Disable  
9:6  
10  
R/W  
R/W  
0001b  
1b  
0001b  
1b  
Disable the LINK_ACT_LED Blink  
Logic.  
0b = Enable logic.  
1b = Disable logic.  
Disable the LINK_ACT_LED Extension  
Logic.  
0b = Enable logic.  
1b = Disable logic.  
LED Stretch Disable  
11  
R/W  
0b  
0b  
Note: Only when both the stretch and  
blink are disabled the input bypasses  
the blink logic and is muxed out with no  
sampling (only combinational logic).  
When set to 1b, all LED outputs are  
inverted.  
Invert Select  
Reserved  
12  
R/W  
R/W  
0b  
0b  
Always read as 0b. Write to 0b for  
normal operation  
14:13  
00b  
00b  
This bit is used to disable special power  
saving in 10BASE-T mode and parallel  
detection. When set to 1b, power  
reduction features of 10BASE-10 are  
disabled (reserved for customers).  
Disable 10 Power  
Saving  
15  
R/W  
0b  
0b  
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13.4.7.1.20 PHY Global Status (82544GC/EI Only)  
PGSTAT (23d; R)  
Table 13-44. PHY Global Status Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
0b  
SW Rst  
0b = No Interrupt on Port.  
1b = Interrupt on Port.  
Port 0 Interrupt  
0
RO  
0b  
0b = No Interrupt on Port.  
1b = Interrupt on Port.  
Port 1 Interrupt  
Port 2 Interrupt  
1
2
RO  
RO  
0b  
0b  
0b  
0b  
0b = No Interrupt on Port.  
1b = Interrupt on Port.  
0b = No Interrupt on Port.  
1b = Interrupt on Port.  
Port 3 Interrupt  
Reserved  
3
RO  
RO  
0b  
0b  
0b  
0b  
15:4  
Reserved. Should be set to 0b.  
NOTE: Bits 3:0 remain high until the active corresponding interrupt bits are cleared on a read of the PHY  
Interrupt Status Register.  
13.4.7.1.21 SPEED_100_LED and SPEED_1000_LED Control (82541xx and 82547GI/EI Only)  
(24d; R/W)  
Table 13-45. SPEED_100_LED and SPEED_1000_LED Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
MUX the designated input to  
SPEED_100_LED.  
LED Source Select  
3:0  
R/W  
0011b  
0011b  
Disable the SPEED_100_LED Blink  
Logic.  
0b = Enable logic.  
1b = Disable logic.  
LED Blink Disable  
4
5
R/W  
R/W  
0b  
1b  
0b  
1b  
Disable the SPEED_100_LED  
Extension Logic.  
0b = Enable logic.  
1b = Disable logic.  
LED Stretch Disable  
Note: Only when both the stretch and  
blink are disabled the input bypasses  
the blink logic and is muxed out with no  
sampling (only combinational logic).  
Mux the designated input to  
SPEED_1000_LED.  
LED Source Select  
LED Blink Disable  
9:6  
10  
R/W  
R/W  
0100b  
0b  
0100b  
0b  
Disable the SPEED_1000_LED Blink  
Logic.  
0b = Enable logic.  
1b = Disable logic.  
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Register Descriptions  
Table 13-45. SPEED_100_LED and SPEED_1000_LED Bit Description  
Disable the SPEED_1000_LED  
Extension Logic.  
0b = Enable logic.  
1b = Disable logic.  
LED Stretch Disable  
11  
R/W  
R/W  
1b  
1b  
Note: Only when both the stretch and  
blink are disabled the input bypasses  
the blink logic and is muxed out with no  
sampling (only combinational logic).  
Always read as 0b. Write to 0b for  
normal operation  
Reserved  
15:12  
00b  
00b  
13.4.7.1.22 PHY LED Control Register (82544GC/EI Only)  
PLED (24d; R/W)  
Table 13-46. PHY LED Control Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
1b = Activity/Link.  
LED_TX control  
0
R/W  
0b  
Retain  
0b = Transmit activity.  
1b = Receive activity/Link.  
0b = Receive activity.  
LED_RX control  
Reserved  
1
2
R/W  
R/W  
0b  
0b  
Retain  
Retain  
Reserved. Should be set to 0b.  
1xb = Link[2:1], Link.  
01b = Link, Speed[1:0].  
00b = Link[2:0].  
LED_LINK control  
Reserved  
4:3  
7:5  
R/W  
R/W  
00b  
Retain  
Retain  
Reserved. Should be set to 000b.  
000b  
000b = 42 ms.  
001b = 84 ms.  
010b = 170 ms.  
011b = 340 ms.  
100b = 670 ms.  
101b to 111b = Reserved.  
Blink Rate  
10:8  
R/W  
R/W  
001b  
0b  
Retain  
Retain  
0b = Do not force INT# assertion.  
1b = Force INT# assertion.  
Force INT# to Assert 11  
000b = no pulse stretching.  
001b = 21 ms to 42 ms.  
010b = 42 ms to 84 ms.  
01b1 = 84 ms to 170 ms.  
100b = 170 ms to 340 ms.  
101b = 340 ms to 670 ms.  
110b = 670 ms to 1.3 s.  
111b = 1.3s to 2.7 s.  
Pulse stretch duration 14:12  
R/W  
R/W  
100b  
Retain  
Retain  
0b = Enable.  
1b = Disable.  
Disable LED  
15  
0b  
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13.4.7.1.23 Extended PHY Specific Control Register 2  
EPSCON2 (26d; R/W)  
Table 13-47. Extended PHY Specific Control Register 2 Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
111b = 1.2, 100b = 0.9, 001b = 0.6  
110b = 1.1, 011b = 0.8, 000b = 0.5  
101b = 1.0, 010b = 0.7  
Fiber Output  
Amplitude  
2:0  
R/W  
100b  
Retain  
Reserved  
Reserved  
3
4
Reserved. Should be set to 1b.  
Reserved. Should be set to 0b.  
R/W  
R/W  
1b  
0b  
1b  
0b  
1b= 75 ohm.  
0b = 50 ohm.  
Fiber Output  
Impedance  
5
R/W  
0b  
Update  
1b = 75 ohm.  
0b = 50 ohm.  
Fiber Input  
Impedance  
6
R/W  
R/W  
0b  
Update  
000h  
Reserved  
15:7  
Reserved. Should be set to 0b.  
000h  
NOTE: Not applicable to the 82540EP/EM, 82544GC/EI, 82541xx, or 82547GI/EI.  
13.4.7.1.24 Extended PHY Specific Status Register (82544GC/EI Only)  
EPSSTAT (27d; R)  
Table 13-48. Extended PHY Specific Status Bit Description  
Field  
MODE[3:0]  
Reserved  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
27.3:0  
MODE[3:0].  
RO  
MODE[3:0] Retain  
Reserved. Should be set to  
000000000000b.  
27.15:4  
RO  
0b  
0b  
1
13.4.7.1.25 MDI Register 30 Page Select  
R30PS (29d; WO)  
Table 13-49. MDI Register 30 Page Select Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
Register 30 Page  
Select  
Selects the register accessible via the  
“window” at MDI register 30.  
15:0  
R/W  
0000h  
0000h  
1. Not applicable to the 82544GC/EI, 82541xx, or 82547GI/EI.  
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13.4.7.1.26 MDI Register 30 Access Window  
R30AW (30d; R/W)  
Table 13-50. MDI Register 30 Page Select Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
0000h  
Provides read/write capability for  
register selected via MDI register 29.  
Register 30 Access  
15:0  
R/W  
0000h  
1
13.4.7.1.27 Documented MDI Register 30 Operations  
Unless otherwise specified, no reset operations are required in order for the following operations to  
take effect.  
Table 13-51. MDI Register 30 Operations  
To Perform  
Operation  
30_31.15:0 <= x2001h  
30_5.8 <= 0b  
MDI Read/Write Sequence  
•
•
Write MDI register 29 <= 31d  
Write MDI register 30 <= 2001h  
Power down SerDes (optimize  
power for copper PHY operation)1  
•
•
•
•
Write MDI register 29 <= 5d  
Read MDI register 30  
Change bit 8 to 0  
Write result to MDI register 30  
Tune VCO on SerDes Rx for  
optimal Bit Error Ratio (BER)1  
•
•
•
•
Write MDI register 29 <= 4d  
Read MDI register 30  
30_4.11 <= 1b  
Change bit 11 to 1  
Write result to MDI register 30  
Set PHY output drivers into Class A  
mode (Class AB is default after  
reset)  
•
•
Write MDI register 29 = 11d  
Write MDI register 30 = 8004h  
30_11.15:0 = 8004h  
1.  
Not applicable to 82540EP/EM  
NOTE: Any time the PHY is reset it returns to Class AB drive mode.  
1. Not applicable to the 82544GC/EI, 82541xx, or 82547GI/EI.  
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13.4.7.1.28 PHY Page Select Register (82541xx and 82547GI/EI Only)  
PPAGE (31d; R/W)  
Table 13-52. PHY Page Select Register Bit Description  
Field  
Bit(s)  
Description  
Mode  
HW Rst  
SW Rst  
This register is used to swap out the  
Base Page containing the IEEE  
registers for Intel reserved test and  
debug pages residing within the  
Extended Address space.  
PAGE_SEL  
15:0  
WO  
0b  
0b  
13.4.8  
Flow Control Address Low  
FCAL (00028h; R/W)  
Flow control packets are defined by IEEE 802.3x to be either a unique multicast address or the  
station address with the EtherType field indicating PAUSE. The FCAL, FCAH registers provide  
the value hardware compares incoming packets against to determine that it should PAUSE its  
output, and hardware use when transmit PAUSE packets to its remote node when flow control is  
activated.  
The FCAL register contains the lower bits of the internal 48-bit Flow Control Ethernet address. All  
32 bits are valid. Software can access the High and Low registers as a register pair if it can perform  
a 64-bit access to the PCI bus. This register should be programmed with 00_C2_80_01h. The  
complete flow control multicast address is: 01_80_C2_00_00_01h; where 01h is the first byte on  
the wire, 80h is the second, etc.  
Table 13-53. FCAL Register Bit Description  
31  
0
FCAL  
Initial  
Value  
Field  
Bit(s)  
Description  
Flow Control Address Low  
Should be programmed with 00_C2_80_01h  
FCAL  
31:0  
X
13.4.9  
Flow Control Address High  
FCAH (0002Ch; R/W)  
This register contains the upper bits of the 48-bit Flow Control Ethernet address. Only the lower 16  
bits of this register have meaning. The complete Flow Control address is {FCAH, FCAL}. This  
register should be programmed with 01_00h. The complete flow control multicast address is:  
01_80_C2_00_00_01h; where 01h is the first byte on the wire, 80h is the second, etc.  
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Table 13-54. FCAH Register Bit Description  
31  
16 15  
0
Reserved  
FCAH  
Initial  
Value  
Field  
Bit(s)  
Description  
Flow Control Address High  
Should be programmed with 0100h.  
FCAH  
15:0  
X
Reserved  
Reserved  
31:16  
0b  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
13.4.10 Flow Control Type  
FCT (00030h; R/W)  
This register contains the type field that hardware matches to recognize a flow control packet and  
that hardware uses when transmitting a PAUSE packet to its remote node. Only the lower 16 bits of  
this register have meaning. This register should be programmed with 88_08h. The upper byte is  
first on the wire FCT[15:8].  
Table 13-55. FCT Register Bit Description  
31  
16 15  
0
Reserved  
FCT  
Initial  
Value  
Field  
Bit(s)  
Description  
Flow Control Type  
Should be programmed with 88_08h.  
FCT  
15:0  
X
Reserved  
Reserved  
31:16  
0b  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
13.4.11 VLAN Ether Type  
VET (00038h; R/W)  
This register contains the type field hardware matches against to recognize an 802.1Q (VLAN)  
Ethernet packet and uses when add and transmit VLAN Ethernet packets. To be compliant with the  
802.3ac standard, this register should be programmed with the value 8100h. For VLAN  
transmission the upper byte is first on the wire (VET[15:8]).  
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Table 13-56. VET Register Bit Description  
31  
16 15  
0
Reserved  
VET  
Initial  
Value  
Field  
Bit(s)  
Description  
VLAN EtherType  
Should be programmed with 8100h.  
VET  
15:0  
X
Reserved  
Reads as 0b.  
Reserved  
31:16  
0b  
13.4.12 Flow Control Transmit Timer Value  
FCTTV (00170h; R/W)  
Provides the Pause slot time value to be included in the transmitted XOFF Pause packets.  
The slot time value that is used is a fixed slot of 64-byte time.  
Table 13-57. FCTTV Register Bit Description  
31  
16 15  
0
Reserved  
TTV  
Initial  
Value  
Field  
Bit(s)  
Description  
Transmit Timer Value  
Slot time value (Slot time value is 64-byte time) to be inserted into  
the transmitted Pause frame. If software wishes to send XON  
frame, it should set the FCTTV. TTV value to 0b prior to initializing  
the Pause frame.  
TTV  
15:0  
X
Reserved  
Reserved  
31:16  
0b  
Reads as 0b.  
Should be written to 0b for future compatibility.  
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Register Descriptions  
13.4.13 Transmit Configuration Word Register1  
TXCW (00178h; R/W)  
This register is applicable to the TBI mode/internal SerDes mode of operation. For internal PHY  
operation, program the register to 0000h. For example, clear this register in MMI mode.  
This register has two meanings, depending on the state of Auto-Negotiation: one as the “AN  
advertise register” defined by IEEE 802.3z, and the other as a register for software control of the  
Auto-Negotiation process.  
When performing hardware Auto-Negotiation, it fulfills the function defined by sub-clause  
37.3.6.1.3 of IEEE 802.3z.  
Table 13-58. TXCW Register Bit Description  
31  
30  
29  
16 15  
0
A
Tx  
Reserved  
TxConfigWord  
Initial  
Value  
Field  
Bit(s)  
Description  
Data transmitted during Auto-Negotiation process.  
When performing hardware Auto-Negotiation (TXCW.ANE is  
set), the value of TxConfigWord is encoded as two 10-  
bit symbols and sent as the “config_word” field for the /C/  
ordered set. When the Ethernet controller performs software  
Auto-Negotiation, TxConfig and TxConfigWord are used to  
negotiate with the link partner. Data stored in TxConfigWord is  
transmitted during the Auto-Negotiation process. Software  
should not read back the contents of this field as content might  
change during the software Auto-Negotiation process. In the  
absence of loss of synchronization, the value read back is stable  
and equal to the value written.  
The mapping of the TxConfigWord is as follows:  
TxConfigWord  
15:0  
0b  
•
•
•
•
•
•
•
•
TxConfigWord[15] Next page request  
TxConfigWord[14] Reserved (write as 0b; ignore on read)  
TxConfigWord[13:12] Remote fault indication  
TxConfigWord[11:9] Reserved (write as 0b; ignore on read)  
TxConfigWord[8:7] Pause  
TxConfigWord[6] Half-duplex  
TxConfigWord[5] Full-duplex  
TxConfigWord[4:0] Reserved (write as 0b; ignore on read)  
Bits 5,7 & 8 of TxConfigWord are loadable from the EEPROM  
upon power-up, or chip reset.  
Reserved  
Reads as 0b.  
Should be written to 0b for future compatibility.  
Reserved  
29:16  
0b  
1. Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Transmit Config Control bit  
0b = Transmit data/idle  
1b = Transmit /C/ ordered sets  
TxConfig  
30  
0b  
Setting the TxConfig bit causes transmission of /C/ ordered set in  
a software controlled Auto-Negotiation process  
(TXCW.ANE=0b).  
Auto-Negotiation Enable.  
1b = Enable the hardware Auto-Negotiation state machine.  
0b = Disable the hardware Auto-Negotiation state machine.  
This bit has the same function as bit 0.12 defined in sub-clause  
22.2.4.1.4 of the 802.3z standard. Since this bit is a “static”  
value, a pulse is generated by hardware in response to writing  
this bit with a 1b. This pulse is used to restart the Auto-  
Negotiation state machine.  
ANE  
31  
0b  
When ANE is set, a transition from loss of synchronization to  
synchronized state restarts the Auto-Negotiation as well.  
If ANE is cleared, then the Ethernet controller is performing  
software Auto-Negotiation. In that case TxConfig and  
TxConfigWord are used to negotiate with the link partner.  
The ANE is loadable from the EEPROM upon power up or chip  
reset.  
Note: Careful attention to the IEEE 802.3z standard is required in order to meet specified timing  
requirements for timing during a software negotiated link.  
13.4.14 Receive Configuration Word Register1  
RXCW (00180h; R)  
This register has meaning only in TBI/internal SerDes mode of operation. The RXCW register  
records the partner abilities and provides indications about its Auto-Negotiation status.  
The contents of this register depend on the state of TXCW.ANE. If ANE is set, then this register  
records the 16-bit defined in IEEE 802.3z. When performing software Auto-Negotiation, software  
should look for RXCW.ANC. When RXCW.ANC is set, the contents of RXCW.RxConfigWord are  
valid, when RXCW.ANC is cleared, then the content of this register is undefined.  
Note: While in internal SerDes mode (82546GB/EB and 82545GM/EM only), software might be  
required to inspect or monitor the results of RXCW to generate a link up/down indication.  
1. Not applicable to the 82541xx, 82547GI/EI, or 82540EP/EM.  
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Table 13-59. RXCW Register Bit Description  
Initial  
Value  
Field  
Bit(s)  
Description  
Data received during Auto-Negotiation process.  
When performing hardware Auto-Negotiation  
(TXCW.ANE = 1b), the “AN link partner ability base page  
register” is recorded in the RxConfigWord.  
When TXCW.ANE is clear, then this register is used by  
software to perform software based Auto-Negotiation. In  
that capacity, RxConfigWord records the raw values  
returned from the Auto-Negotiation process.  
RxConfigWord  
15:0  
X
Reserved  
Reserved  
25:16  
0b  
Reads as 0b.  
Should be written with 0b for future compatibility.  
Carrier Sense Indication  
0b = Ethernet controller not receiving idle characters  
(Carrier sense is true)  
1b = Ethernet controller receiving idle characters (Carrier  
sense is false)  
Hardware sets RxConfigNoCarrier when it is receiving idle  
characters (and when receiving link configuration  
information or port status).  
RxConfigNoCarrier  
26  
0b  
Software can use this bit to determine that idles have been  
seen prior to exiting the link start-up procedure.  
82544GC/EI only:  
Valid only in software Auto-Negotiation mode  
(TXCW.ANE = 0b).  
Invalid Symbol during configuration process  
0b = Have not received an invalid symbol during Auto-  
Negotiation process.  
1b = Have received an invalid symbol during Auto-  
Negotiation process (bit is LH).  
If the Ethernet controller detects an invalid symbol at any  
time, it sets the RxConfigInvalid bit. The bit is latched high  
until read by software. Software is expected to restart the  
configuration process when the Ethernet controller receives  
an invalid symbol at any time during the Auto-Negotiation  
process.  
RxConfigInvalid  
27  
0b  
82544GC/EI only:  
Valid only in software Auto-Negotiation mode  
(TXCW.ANE = 0b).  
Change to the RxConfigWord indication  
0b = RxConfigWord has changed since last read.  
1b = RxConfig is unchanged since last read (LH)  
Indicates that the Ethernet controller interface has seen a  
change to the RxConfigWord. This bit is latched high until  
read by software.  
RxConfigChange  
28  
0b  
82544GC/EI only:  
Valid only in software Auto-Negotiation mode  
(TXCW.ANE = 0b).  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
/C/ order set reception indication  
0b = Receive idle/data stream.  
1b = Receiving /C/ order sets.  
Provides an indication as to whether the interface is  
receiving /C/ order set, or normal idle/data stream.  
82544GC/EI only:  
RxConfig  
29  
0b  
Valid only in software Auto-Negotiation mode  
(TXCW.ANE = 0b).  
Lost bit synchronization indication  
0b = Lost synchronization.  
1b = Bit synchronization (bit is LL).  
Used to qualify all other bits in the register (when in  
software Auto-Negotiation).  
Each time the Ethernet controller loses bit synchronization,  
this bit becomes ‘0b’ and stays ‘0b’ until read by software.  
82544GC/EI only:  
RxSynchronize  
30  
0b  
Valid only in software Auto-Negotiation mode  
(TXCW.ANE = 0b).  
Auto Negotiation Complete  
0b = The contents of the register are undefined in hardware  
Auto-Negotiation mode (TXCW.ANE = 1b)  
1b = The contents of the register are valid in hardware Auto-  
Negotiation mode.  
Reports the status as required in sub-clause 22.2.4.2.11.  
This bit remains cleared from the time Auto-Negotiation is  
reset until Auto-Negotiation reaches the “LINK_OK” state.  
It remains set until Auto-Negotiation is disabled or restarted.  
This bit has meaning only if TXCW.ANE = 1b. If software  
Auto-Negotiation is used, it always reads 0b and should be  
ignored.  
ANC  
31  
0b  
13.4.15 LED Control1  
LEDCTL (00E00h; RW)  
31 - 24  
23 - 16  
15 - 8  
7 - 0  
LED3 (LINK1000#)  
LED2 (LINK100#)  
LED1 ACTIVITY#)  
LED0 (LINK_UP#)  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
1
Table 13-60. LED Control Bit Description  
Initial  
Value  
Field  
Bit  
Description  
LED0/LINK# Mode. This field specifies the control source for the  
LED0 output. An initial value of 0010b selects LINK_UP# indication.  
LED0_MODE  
Reserved  
3:0  
0010b1  
00b  
5:4  
6
Reserved. Read-only as 0b. Write as 0b for future compatibility.  
LED0/LINK# Invert. This field specifies the polarity/ inversion of the  
LED source prior to output or blink control.  
0b = do not invert LED source.  
LED0_IVRT  
0b1  
1b = invert LED source.  
LED0/LINK# Blink. This field specifies whether to apply blink logic to  
the (possibly inverted) LED control source prior to the LED output.  
0b = do not blink asserted LED output.  
LED0_BLINK  
LED1_MODE  
7
0b1  
1b = blink asserted LED output.  
LED1/ACTIVITY# Mode. This field specifies the control source for the  
LED1 output. An initial value of 0011b selects ACTIVITY# indication.  
11:8  
0011b  
Reserved  
13:12  
14  
00b  
0b  
Reserved. Read-only as 0b. Write as 0b for future compatibility.  
LED1/ACTIVITY# Invert.  
LED1_IVRT  
LED1_BLINK  
15  
1b  
LED1/ACTIVITY# Blink.  
LED2/LINK100# Mode. This field specifies the control source for the  
LED2 output. An initial value of 0011b selects LINK100# indication.  
LED2_MODE  
19:16  
0110b1  
Reserved  
21:20  
22  
00b  
0b1  
0b1  
Reserved. Read-only as 0b. Write as 0b for future compatibility.  
LED2/LINK100# Invert.  
LED2_IVRT  
LED2_BLINK  
23  
LED2/LINK100# Blink.  
LED3/LINK1000# Mode. This field specifies the control source for the  
LED3 output. An initial value of 0111b selects LINK1000# indication.  
LED3_MODE  
27:24  
0111b  
Reserved  
29:28  
30  
00b  
0b  
Reserved. Read-only as 0b. Write as 0b for future compatibility.  
LED3/LINK1000# Invert.  
LED3_IVRT  
LED3_BLINK  
31  
0b  
LED3/LINK1000# Blink.  
1.  
These bits are read from the EEPROM.  
1
13.4.15.1 MODE Encodings for LED Outputs  
The Table 13-61 lists the MODE encodings used to select the desired LED signal source for each  
LED output. Refer to Section 10.1.1 to ensure proper understanding of expression polarity and  
resulting LED output polarity.  
Note: All 16 modes listed are functional.  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
1
Table 13-61. Mode Encodings for LED Outputs  
Mode  
Pneumonic  
State / Event Indicated  
Asserted when either 10 or 1000 Mbps link is  
established and maintained.  
0000b  
LINK_10/1000  
Asserted when either 100 or 1000 Mbps link is  
established and maintained.  
0001b  
0010b  
LINK_100/1000  
LINK_UP  
Asserted when any speed link is established and  
maintained.  
Asserted when link is established and packets are  
being transmitted or receive activity that passes  
filtering.  
0011b  
ACTIVITY  
Asserted when link is established and when there is  
no transmit or receive activity that passes filtering.  
0100b  
0101b  
0110b  
0111b  
1000b  
LINK/ACTIVITY  
LINK_10  
Asserted when a 10 Mbps link is established and  
maintained.  
Asserted when a 100 Mbps link is established and  
maintained.  
LINK_100  
Asserted when a 1000 Mbps link is established and  
maintained.  
LINK_1000  
PCIX_MODE  
Asserted when Ethernet controller is in PCI-X mode  
(deasserted in PCI mode).  
Asserted when the link is configured for full duplex  
operation (deasserted in half-duplex).  
1001b  
1010b  
FULL_DUPLEX  
COLLISION  
Asserted when a collision is observed.  
Asserted when the Ethernet controller is operating  
in a PCI 66 MHz or a PCI-X 133 MHz configuration  
(high-speed PCI operation), deasserted for 33 MHz  
PCI and 66 MHz PCI-X (as determined by pins  
sampled at PCI reset).  
1011b  
BUS_SPEED  
BUS_SIZE  
Reserved for the  
82547GI/EI only)  
Asserted when the Ethernet controller is operating  
as a 64-bit PCI or PCI-X device, deasserted for 32-  
bit configuration.  
1100b  
1101b  
1110b  
Asserted when the Ethernet controller’s transmitter  
is flow controlled.  
PAUSED  
Always high. Assuming no optional inversion  
selected, causes output pin high / LED ON for  
typical LED circuit.  
VCC/LED_ON  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
Mode  
Pneumonic  
State / Event Indicated  
Always low. Assuming no optional inversion  
selected, causes output pin low / LED OFF for  
typical LED circuit.  
1111b  
GND/LED_OFF  
13.4.16 Packet Buffer Allocation  
PBA (01000H; R/W)  
This register sets the on-chip receive and transmit storage allocation ratio. The receive allocation  
value is read/write for the lower seven bits. The receive allocation value must be a multiple of eight  
(multiple of two for the 82547GI/EI B1 stepping). The transmit allocation is read-only and is  
calculated based on PBA.RXA.  
Table 13-62. PBA Register Bit Description  
31  
16 15  
0
TXA  
RXA  
Field  
Bit(s)  
Initial Value  
Description  
Receive Packet Buffer Allocation in KB  
Sets the size of the receive packet buffer.  
The value of this field must be a multiple of eight.  
The upper nine bits are read only as 0b. Default is  
48 KB.  
0030h1  
6:0  
0016h (82547EI A0-B0  
steppings)  
RXA  
15:0 (82541xx  
and 82547GI/EI)  
001Eh (82547GI B1  
stepping)  
For the 82541xx and 82547GI/EI, the upper unused  
bits are read only as 0b. The default is 48 KB for the  
82541xx, 24 KB for the 82547EI, and 20 KB for the  
82547GI.  
Receive Packet Buffer Allocation – Upper Bits  
Provides the upper nine bits of the receive packet  
buffer allocation.  
RXA_R2 15:7  
0b  
Read only bits - Read as 0b.  
Transmit Packet Buffer Allocation  
0010h  
Provides the size of the transmit packet buffer. The  
value is in units of KB. These bits are read only.  
TXA is calculated based on RXA value: TXA = 64 –  
RXA.  
31:16  
TXA  
0012h (82547EI A0-B0  
steppings)  
15:00 (82541xx  
and 82547GI/EI)  
000Ah (82547GI B1  
stepping)  
For the 82547GI/EI, TXA is calculated based on  
RXA value: TXA = 40 – RXA.  
1.  
2.  
Not applicable to the 82547GI/EI.  
Not applicable to the 82541xx or 82547GI/EI.  
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Register Descriptions  
13.4.17 Interrupt Cause Read Register  
ICR (000C0H; R)  
This register contains all interrupt conditions for the Ethernet controller. Each time an interrupt  
causing event occurs, the corresponding interrupt bit is set in this register. A PCI interrupt is  
generated each time one of the bits in this register is set, and the corresponding interrupt is enabled  
through the Interrupt Mask Set/Read IMS Register (see Section 13.4.20).  
All register bits are cleared upon read. As a result, reading this register implicitly acknowledges  
any pending interrupt events. Writing a 1b to any bit in the register also clears that bit. Writing a 0b  
to any bit has no effect on that bit.  
Table 13-63. ICR Register Bit Description  
31 - 17  
16 14  
0
Reserved  
ICR Bits  
Initial  
Value  
Field  
Bit(s)  
Description  
Transmit Descriptor Written Back  
Set when hardware processes a transmit descriptor with the RS  
bit set (and possibly IDE set). If using delayed interrupts (IDE set),  
the interrupt occurs after the timer expires.  
TXDW  
0
1
2
0b  
Transmit Queue Empty  
Set when the last descriptor block for a transmit queue has been  
used.  
TXQE  
LSC  
0b  
0b  
Link Status Change  
This bit is set each time the link status changes (either from up to  
down, or from down to up). This bit is affected by the internal link  
indication when configured for internal PHY mode.  
Receive Sequence Error  
In TBI mode/internal SerDes1, incoming packets with a bad  
delimiter sequence set this bit. In other 802.3 implementations,  
this would be classified as a framing error. A valid sequence  
consists of:  
RXSEQ  
3
0b  
idle SOF data pad (opt) EOF fill (opt) idle.  
This is a reserved bit for the 82541xx, 82547GI/EI, and 82540EP/  
EM. Set to 0b.  
Receive Descriptor Minimum Threshold Reached  
RXDMT0  
Reserved  
4
5
0b  
0b  
Indicates that the minimum number of receive descriptors are  
available and software should load more receive descriptors.  
Reserved  
Reads as 0b.  
Receiver Overrun  
Set on receive data FIFO overrun. Could be caused either  
because there are no available receive buffers or because PCI  
receive bandwidth is inadequate.  
RXO  
6
0b  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Receiver Timer Interrupt  
Set when the receiver timer expires.  
RXT0  
7
0b  
The receiver timer is used for receiver descriptor packing. Timer  
expiration flushes any accumulated descriptors and sets an  
interrupt event when enabled.  
Reserved  
Reads as 0b.  
Reserved  
MDAC  
8
9
0b  
0b  
MDI/O Access Complete  
This bit is set when the MDI/O access is completed.  
Receiving /C/ ordered sets  
Mapped to RXCW.RxConfig.  
Sets when the hardware receives configuration symbols (/C/  
codes). Software should enable this interrupt when forcing link.  
When the link is forced, the link partner can begin to Auto-  
Negotiate based, due to a reset or enabling of Auto-Negotiation.  
The reception of /C/ codes causes an interrupt to software and the  
proper hardware configuration might be set.  
RXCFG  
10  
0b  
See Section 13.4.14 for details. Only valid in internal SerDes  
mode (TBI mode for the 82544GC/EI).  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to 0b.  
Reserved. Set this bit to 0b.  
Not applicable to the 82544GC/EI.  
Reserved  
11  
12  
0b  
0b  
PHY Interrupt (not applicable to the 82544GC/EI)  
Set when the PHY generates an interrupt.  
If bit 1 (PHYINT_EN) of the CTRL_EXT register (00018h) is set,  
then this bit gets set.  
PHYINT  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to 0b.  
GPI_SDP6  
General Purpose Interrupt on SDP6[2]. If GPI interrupt detection is  
enabled on this pin (via CTRL_EXT), this interrupt cause is set  
when the SDP6[2] is sampled high.  
13  
14  
0b  
0b  
GPI_SDP2  
(82541xx and  
82547GI/EI)  
Not applicable to the 82544GC/EI.  
GPI_SDP7  
General Purpose Interrupt on SDP7[3]. If GPI interrupt detection is  
enabled on this pin (via CTRL_EXT), this interrupt cause is set  
when the SDP7[3] is sampled high.  
GPI_SDP3  
(82541xx and  
82547GI/EI)  
Not applicable to the 82544GC/EI.  
General Purpose Interrupts (82544GC/EI only)  
These bits are mapped to the upper three SDP pins when they are  
configured as inputs. Refer to Section 13.4.6.  
14:13,  
11  
GPI  
0b  
0b  
Transmit Descriptor Low Threshold hit.  
Indicates that the descriptor ring has reached the threshold  
specified in the Transmit Descriptor Control register.  
TXD_LOW2  
15  
16  
Small Receive Packet Detected.  
Indicates that a packet of size RSRPD.SIZE register has been  
detected and transferred to host memory. The interrupt is only  
asserted if RSRPD.SIZE register has a non-zero value.  
SRPD2  
0b  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Reserved  
Reads as 0b.  
Reserved  
31:17  
0b  
1.  
2.  
The 82540EP/EM, 82541xx, or 82547GI/EI do not support SerDes functionality.  
Not applicable to the 82544GC/EI.  
Note: The 82547GI/EI signals interrupts over the CSA port, not a dedicated interrupt pin.  
13.4.18 Interrupt Throttling Register1  
ITR (000C4h; R/W)  
31 - 16  
15 - 0  
Reserved  
INTERVAL  
Initial  
Value  
Field  
Bit(s)  
Description  
Minimum inter-interrupt interval. The interval is specified in 256 ns  
increments. Setting this bit to 0b disables interrupt throttling logic.  
INTERVAL  
Reserved  
15:0  
31:16  
0b  
X
Reserved. Should be written with 0b to ensure future compatibility.  
Software can use this register to pace (or even out) the delivery of interrupts to the host CPU. This  
register provides a guaranteed inter-interrupt delay between interrupts asserted by the Ethernet  
controller, regardless of network traffic conditions. To independently validate configuration  
settings, software can use the following algorithm to convert the inter-interrupt interval value to the  
common interrupts/sec performance metric:  
interrupts/second = 25610–9 interval–1  
For example, if the interval is programmed to 500d, the Ethernet controller guarantees the CPU is  
not interrupted by the Ethernet controller for 128 sec from the last interrupt. The maximum  
observable interrupt rate from the Ethernet controller must never exceed 7813 interrupts/sec.  
Inversely, inter-interrupt interval value can be calculated as:  
inter-interrupt interval = 25610–9 interrupts/sec–1  
The optimal performance setting for this register is very system and configuration specific. A  
initial suggested range is 651-5580 (28Bh - 15CCh).  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
13.4.19 Interrupt Cause Set Register  
ICS (000C8h; W)  
Software uses this register to set an interrupt condition. Any bit written with a 1b sets the  
corresponding interrupt. This results in the corresponding bit being set in the Interrupt Cause Read  
Register (see Section 13.4.17). A PCI interrupt is generated if one of the bits in this register is set  
and the corresponding interrupt is enabled through the Interrupt Mask Set/Read Register (see  
Section 13.4.20).  
Bits written with 0b are unchanged.  
Table 13-64. ICS Register Bit Description  
31  
17 16  
0
Reserved  
ICS Bits  
Initial  
Value  
Field  
Bit(s)  
Description  
TXDW  
TXQE  
LSC  
0
1
2
X
X
X
Sets Transmit Descriptor Written Back Interrupt.  
Sets Transmit Queue Empty Interrupt.  
Sets Link Status Change Interrupt.  
Sets Receive Sequence Error Interrupt.  
RXSEQ  
3
X
This is a reserved bit for the 82541xx and 82547GI/EI. Set to  
0b.  
Sets Receive Descriptor Minimum Threshold Reached  
Interrupt.  
RXDMT0  
Reserved  
4
5
X
X
Reserved  
Should be written with 0b to ensure future compatibility.  
RXO  
6
7
X
X
Sets on Receiver FIFO Overrun Interrupt.  
Sets Receiver Timer Interrupt.  
RXT0  
Reserved  
Reserved  
MDAC  
8
9
X
X
Should be written with 0b to ensure future compatibility.  
Sets MDI/O Access Complete Interrupt.  
Sets Receiving /C/ ordered sets Interrupt.  
RXCFG  
Reserved  
PHYINT  
10  
11  
12  
X
X
X
This is a reserved bit for the 82541xx and 82547GI/EI. Set to  
0b.  
Reserved  
Should be written with 0b to ensure future compatibility.  
Not applicable to the 82544GC/EI.  
Sets PHY interrupt. Not applicable to the 82544GC/EI.  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to  
0b.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
GPI  
GPI  
14:11  
14:13  
X
X
Sets General Purpose Interrupts (82544GC/EI only).  
Sets General Purpose Interrupts.  
Transmit Descriptor Low Threshold Hit. Not applicable to the  
82544GC/EI.  
TXD_LOW  
SRPD  
15  
X
X
X
Small Receive Packet Detected and Transferred. Not applicable  
to the 82544GC/EI.  
16  
Reserved  
Reserved  
31:17  
Should be written with 0b to ensure future compatibility.  
13.4.20 Interrupt Mask Set/Read Register  
IMS (000D0h; R/W)  
An interrupt is enabled if its corresponding mask bit is set to 1b, and disabled if its corresponding  
mask bit is set to 0b. A PCI interrupt is generated each time one of the bits in this register is set and  
the corresponding interrupt condition occurs. The occurrence of an interrupt condition is reflected  
by having a bit set in the Interrupt Cause Read Register (see Section 13.4.17).  
A particular interrupt can be enabled by writing a 1b to the corresponding mask bit in this register.  
Any bits written with a 0b are unchanged. As a result, if software desires to disable a particular  
interrupt condition that had been previously enabled, it must write to the Interrupt Mask Clear  
Register (see Section 13.4.21) rather than writing a 0b to a bit in this register.  
Reading this register returns bits that have an interrupt mask set.  
Note: For the 82547GI/EI, programmers need to first write (clear) the IMS and IMC registers due to a  
Hub Link bus being occupied. This results in an interrupt de-assertion message that can’t to be sent  
out. When a future interrupt assertion message is generated, two messages are re-ordered and sent  
out. This signals APIC that the 82547GI/EI is in a de-asserted state when it is actually in an  
asserted state, which causes a system dead lock. To avoid a system dead lock, first clear the IMS  
and IMC registers by writing FFFFh and then re-assert IRQ enable.  
Table 13-65. IMS Register Bit Description  
31  
17 16  
0
Reserved  
IMS Bits  
Initial  
Value  
Field  
Bit(s)  
Description  
TXDW  
TXQE  
LSC  
0
1
2
X
X
X
Sets mask for Transmit Descriptor Written Back.  
Sets mask for Transmit Queue Empty.  
Sets mask for Link Status Change.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Sets mask for Receive Sequence Error.  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to 0b.  
RXSEQ  
3
4
5
X
X
X
RXDMT0  
Reserved  
Sets mask for Receive Descriptor Minimum Threshold hit.  
Reserved  
Should be written with 0b to ensure future compatibility.  
RXO  
6
7
X
X
Sets mask for on Receiver FIFO Overrun.  
Sets mask for Receiver Timer Interrupt.  
RXT0  
Reserved  
Reserved  
MDAC  
8
9
X
X
X
Should be written with 0b to ensure future compatibility.  
Sets mask for MDI/O Access Complete Interrupt.  
Sets mask for Receiving /C/ ordered sets.  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to 0b.  
RXCFG  
10  
11  
12  
Reserved  
Reserved  
PHYINT  
X
X
Should be written with 0b to ensure future compatibility (not  
applicable to the 82544GC/EI).  
Sets mask for PHY Interrupt (not applicable to the 82544GC/EI).  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to 0b.  
GPI  
GPI  
14:11  
14:13  
X
X
Sets mask for General Purpose Interrupts (82544GC/EI only).  
Sets mask for General Purpose Interrupts.  
Sets the mask for Transmit Descriptor Low Threshold hit (not  
applicable to the 82544GC/EI).  
TXD_LOW  
SRPD  
15  
X
X
Sets mask for Small Receive Packet Detection (not applicable to  
the 82544GC/EI).  
16  
Reserved  
Reserved  
31:17  
0b  
Should be written with 0b to ensure future compatibility.  
13.4.21 Interrupt Mask Clear Register  
IMC (000D8h; W)  
Software uses this register to disable an interrupt. Interrupts are presented to the bus interface only  
when the mask bit is set to 1b and the cause bit set to 1b. The status of the mask bit is reflected in  
the Interrupt Mask Set/Read Register (see Section 13.4.20), and the status of the cause bit is  
reflected in the Interrupt Cause Read Register (see Section 13.4.17).  
Software blocks interrupts by clearing the corresponding mask bit. This is accomplished by writing  
a 1b to the corresponding bit in this register. Bits written with 0b are unchanged (their mask status  
does not change).  
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Register Descriptions  
Software should write a 1b to the reserved bits to ensure future compatibility. Since this register  
masks interrupts when 1b is written to the corresponding (defined) bits, then writing 1b to the  
reserved bits ensures that the software is never called to handle an interrupt that the software is not  
aware exists.  
Note: For the 82547GI/EI, programmers need to first write (clear) the IMS and IMC registers due to a  
Hub Link bus being occupied. This results in an interrupt de-assertion message that can’t to be sent  
out. When a future interrupt assertion message is generated, two messages are re-ordered and sent  
out. This signals APIC that the 82547GI/EI is in a de-asserted state when it is actually in an  
asserted state, which causes a system dead lock. To avoid a system dead lock, first clear the IMS  
and IMC registers by writing FFFFh and then re-assert IRQ enable.  
Table 13-66. IMC Register Bit Description  
31  
17 16  
0
Reserved  
IMC Bits  
Initial  
Value  
Field  
Bit(s)  
Description  
TXDW  
TXQE  
LSC  
0
1
2
X
X
X
Clears mask for Transmit Descriptor Written Back.  
Clears mask for Transmit Queue Empty.  
Clears mask for Link Status Change.  
Clears mask for Receive Sequence Error.  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to 0b.  
RXSEQ  
3
4
5
X
X
X
RXDMT0  
Reserved  
Sets mask for Receive Descriptor Minimum Threshold hit.  
Reserved: Should be written with 1b to ensure future  
compatibility.  
RXO  
6
7
X
X
Clears mask for on Receiver FIFO Overrun.  
Clears mask for Receiver Timer Interrupt.  
RXT0  
Reserved: Should be written with 1b to ensure future  
compatibility.  
Reserved  
MDAC  
8
9
X
X
X
Clears mask for MDI/O Access Complete Interrupt.  
Clears mask for Receiving /C/ ordered sets.  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to 0b.  
RXCFG  
10  
11  
12  
Reserved: Should be written with 1b to ensure future  
compatibility (not applicable to the 82544GC/EI).  
Reserved  
PHYINT  
X
X
Clears PHY Interrupts (not applicable to the 82544GC/EI).  
This is a reserved bit for the 82541xx and 82547GI/EI. Set to 0b.  
GPI  
GPI  
14:11  
14:13  
X
X
Clears General Purpose Interrupts (82544GC/EI only).  
Clears General Purpose Interrupts.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Clears the mask for Transmit Descriptor Low Threshold hit (not  
applicable to the 82544GC/EI).  
TXD_LOW  
SRPD  
15  
X
X
X
Clears mask for Small Receive Packet Detect Interrupt (not  
applicable to the 82544GC/EI).  
16  
Reserved  
Reserved  
31:17  
Should be written with 1b to ensure future compatibility.  
13.4.22 Receive Control Register  
RCTL (00100h; R/W)  
This register controls all Ethernet controller receiver functions.  
Table 13-67. RCTL Register Bit Description  
31  
27 26  
0
Reserved  
Receive Control Bits  
Initial  
Value  
Field  
Bit(s)  
Description  
Reserved  
Write to 0b for future compatibility.  
Reserved  
0
0b  
Receiver Enable  
The receiver is enabled when this bit is 1b. Writing this bit to 0b  
stops reception after receipt of any in-progress packets. Data  
remains in the receive FIFO until the device is re–enabled.  
Disabling or re-enabling the receiver does not reinitialize the packet  
filter logic that demarcates packet start and end locations in the  
FIFO; Therefore the receiver must be reset before re-enabling it.  
EN  
1
0b  
0b  
0b  
Store Bad Packets  
0b = do not store.  
1b = store bad packets.  
When set, the Ethernet controller stores bad packets (CRC error,  
symbol error, sequence error, length error, alignment error, short  
packets or where carrier extension or RX_ERR errors) that pass the  
filter function in host memory. When the Ethernet controller is in  
promiscuous mode, and SBP is set, it might possibly store all  
packets.  
SBP  
2
Unicast Promiscuous Enabled  
0b = Disabled.  
1b = Enabled.  
When set, passes without filtering out all received unicast packets.  
Otherwise, the Ethernet controller accepts or rejects unicast  
packets based on the received packet destination address match  
with 1 of the 16 stored addresses.  
UPE  
3
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Multicast Promiscuous Enabled  
0b = Disabled.  
1b = Enabled.  
MPE  
4
0b  
When set, passes without filtering out all received multicast packets.  
Otherwise, the Ethernet controller accepts or rejects a multicast  
packet based on its 4096-bit vector multicast filtering table.  
Long Packet Reception Enable  
0b = Disabled.  
1b = Enabled.  
LPE controls whether long packet reception is permitted. When LPE  
is cleared, the Ethernet controller discards packets longer than  
1522 bytes. When LPE is set, the Ethernet controller discards  
packets that are longer than 16384 bytes.  
For the 82541xx and 82547GI/EI, packets larger than 2 KB require  
full duplex operation.  
LPE  
5
0b  
Loopback mode.  
Controls the loopback mode of the Ethernet controller.  
00b = No loopback.  
01b = Undefined.  
10b = Undefined.  
11b = PHY or external SerDes loopback.  
All loopback modes are only allowed when the Ethernet controller is  
configured for full-duplex operation. Receive data from transmit  
data looped back internally to the SerDes or internal PHY. In TBI  
mode (82544GC/EI), the EWRAP signal is asserted.  
Note: The 82540EP/EM, 82541xx, and 82547GI/EI do not support  
SerDes functionality.  
LBM  
7:6  
0b  
Receive Descriptor Minimum Threshold Size  
The corresponding interrupt ICR.RXDMT0 is set each time the  
fractional number of free descriptors becomes equal to RDMTS.  
The following table lists which fractional values correspond to  
RDMTS values. The size of the total receiver circular descriptor  
buffer is set by RDLEN. See Section 13.4.27 for details regarding  
RDLEN.  
RDMTS  
9:8  
0b  
00b = Free Buffer threshold is set to 1/2 of RDLEN.  
01b = Free Buffer threshold is set to 1/4 of RDLEN.  
10b = Free Buffer threshold is set to 1/8 of RDLEN.  
11b = Reserved.  
Reserved  
Reserved  
11:10  
13:12  
14  
0b  
0b  
0b  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
Multicast Offset  
The Ethernet controller is capable of filtering multicast packets  
based on 4096-bit vector multicast filtering table. The MO  
determines which bits of the incoming multicast address are used in  
looking up the 4096-bit vector.  
00b = bits [47:36] of received destination multicast address.  
01b = bits [46:35] of received destination multicast address.  
10b = bits [45:34] of received destination multicast address.  
11b = bits [43:32] of received destination multicast address.  
MO  
Reserved  
Reserved  
Should be written with 0 to ensure future compatibility  
Reads as 0  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Broadcast Accept Mode.  
0 = ignore broadcast; 1 = accept broadcast packets.  
When set, passes and does not filter out all received broadcast  
packets. Otherwise, the Ethernet controller accepts, or rejects a  
broadcast packet only if it matches through perfect or imperfect  
filters.  
BAM  
15  
0b  
Receive Buffer Size  
Controls the size of the receive buffers, allowing the software to  
trade off between system performance and storage space. Small  
buffers maximize memory efficiency at the cost of multiple  
descriptors for bigger packets.  
RCTL.BSEX = 0b:  
00b = 2048 Bytes.  
01b = 1024 Bytes.  
BSIZE  
17:16  
0b  
10b = 512 Bytes.  
1b1 = 256 Bytes.  
RCTL.BSEX = 1b:  
00b = Reserved; software should not program this value.  
01b = 16384 Bytes.  
10b = 8192 Bytes.  
11b = 4096 Bytes.  
VLAN Filter Enable1  
0b = Disabled (filter table does not decide packet acceptance).  
1b = Enabled (filter table decides packet acceptance for 802.1Q  
packets).  
Three bits control the VLAN filter table. RCTL.VFE determines  
whether the VLAN filter table participates in the packet acceptance  
criteria. RCTL.CFIEN and RCTL.CFI are used to decide whether  
the CFI bit found in the 802.1Q packet’s tag should be used as part  
of the acceptance criteria.  
VFE  
18  
19  
0b  
0b  
Canonical Form Indicator Enable  
0b = Disabled (CFI bit found in received 802.1Q packet’s tag is not  
compared to decide packet acceptance).  
CFIEN  
1b = Enabled (CFI bit found in received 802.1Q packet’s tag must  
match RCTL.CFI to accept 802.1Q type packet.  
Canonical Form Indicator bit value  
CFI  
20  
21  
0b  
0b  
If RCTL.CFIEN is set, then 802.1Q packets with CFI equal to this  
field is accepted; otherwise, the 802.1Q packet is discarded.  
Reserved  
Reserved  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
Discard Pause Frames  
0 = incoming pause frames subject to filter comparison.  
1 = incoming pause frames are filtered out even if they match filter  
registers.  
DPF controls the DMA function of flow control PAUSE packets  
addressed to the station address (RAH/L[0]). If a packet is a valid  
flow control packet and is addressed to the station’s address, it is  
not transferred to host memory if RCTL.DPF = 1b. However, it is  
transferred when DPF is set to 0b.  
DPF  
22  
0b  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Pass MAC Control Frames  
0b = Do not (specially) pass MAC control frames.  
1b = Pass any MAC control frame (type field value of 8808h) that  
does not contain the pause opcode of 0001h.  
PMCF controls the DMA function of MAC control frames (other than  
flow control). A MAC control frame in this context must be  
addressed to either the MAC control frame multicast address or the  
station address, match the type field and NOT match the PAUSE  
opcode of 0001h. If PMCF = 1b then frames meeting this criteria are  
transferred to host memory. Otherwise, they are filtered out.  
PMCF  
23  
0b  
Reserved  
Reserved  
BSEX  
24  
25  
0b  
0b  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
Buffer Size Extension  
When set to one, the original BSIZE values are multiplied by 16.  
Refer to the RCTL.BSIZE bit description.  
Strip Ethernet CRC from incoming packet  
0b = Do not strip CRC field.  
1b = Strip CRC field.  
SECRC  
26  
0b  
Controls whether the hardware strips the Ethernet CRC from the  
received packet. This stripping occurs prior to any checksum  
calculations. The stripped CRC is not transferred to host memory  
and is not included in the length reported in the descriptor.  
Reserved  
Reserved  
31:27  
0b  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
1.  
Not applicable to the 82541ER.  
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Register Descriptions  
13.4.23 Flow Control Receive Threshold Low  
FCRTL (02160h; R/W)  
This register contains the receive threshold used to determine when to send an XON packet. It  
counts in units of bytes. Each time the receive FIFO crosses the receive high threshold  
FCRTH.RTH (filling up), and then crosses the receive low threshold FCRTL.RTL, with  
FCRTL.XONE enabled, hardware transmits an XON frame.  
Flow control reception/transmission are negotiated capabilities by the Auto-Negotiation process.  
When the Ethernet controller is manually configured, flow control operation is determined by the  
CTRL.RFCE and CTRL.TFCE bits.  
Table 13-68. FCRTL Register Bit Description  
31  
30  
16 15  
3 2  
0
XONE1  
Reserved  
RTL  
0
1.  
82544GC/EI, 82541xx, and 82547GI/EI only.  
Initial  
Value  
Field  
Bit(s)  
Description  
Reserved  
Reserved  
2:0  
0b  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
Receive Threshold Low.  
FIFO low water mark for flow control transmission. Each time the  
receive FIFO crosses the receive high threshold FCRTH.RTH and  
later crosses the receive low threshold FCRTL.RTL with  
FCRTL.XONE enabled, hardware transmits an XON frame (a  
PAUSE frame with a timer value of 0b).  
RTL  
15:3  
0b  
RTL is provided in units of 8 bytes.  
Reserved  
Reserved  
XONE  
31:16  
31  
0b  
0b  
Should be written with 0b for future compatibility.  
Reads as 0b.  
XON Enable (82544GC/EI, 82541xx, and 82547GI/EI only)  
0b = Disabled.  
1b = Enabled.  
When set, enables the Ethernet controller to transmit XON packets  
based on receive FIFO crosses FCRTL.RTL threshold value, or  
based on external pins XOFF and XON.  
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Register Descriptions  
13.4.24 Flow Control Receive Threshold High  
FCRTH (02168h; R/W)  
This register contains the receive threshold used to determine when to send an XOFF packet. It  
counts in units of bytes. Each time the receive FIFO reaches the fullness indicated by FCRTH,  
hardware transmits a PAUSE frame if the transmission of flow control frames is enabled  
(CTRL.TFCE).  
Flow control reception/transmission are negotiated capabilities by the Auto-Negotiation process.  
When the Ethernet controller is manually configured, flow control operation is determined by the  
CTRL.RFCE & CTRL.TFCE bits.  
Table 13-69. FCRTH Register Bit Description  
31  
30  
16 15  
3 2  
0
XFCE1  
Reserved  
RTH  
0
1.  
82544GC/EI only.  
Initial  
Value  
Field  
Bit(s)  
Description  
Reserved  
Reserved  
2:0  
0b  
Should be written with 0 for future compatibility  
Reads as 0  
Receive Threshold High.  
FIFO high water mark for flow control transmission.  
Each time the receive FIFO reaches the fullness indicated by RTH,  
the Ethernet controller transmits a Pause packet if enabled to do so.  
RTH  
15:3  
0b  
0b  
Reserved  
Reserved  
31:16  
Should be written with 0b for future compatibility.  
Reads as 0b.  
External Flow Control Enabled (82544GC/EI only)  
0b = Disabled.  
1b = Enabled.  
Allows the Ethernet controller to send XOFF and XON frames based  
on external pins XOFF and XON. The transmission of pause frames  
must be also enabled through the CTRL.TFCE control bit. When the  
XOFF signal is asserted high, the Ethernet controller transmits a  
single XOFF frame. The assertion of XON (after deassertion of  
XOFF) initiates an XON frame transmission, if enabled by  
FCRTL.XONE. The assertion/deassertion of XON is required  
between assertions of XOFF in order to send another XOFF frame.  
This behavior also provides a built-in hysteresis mechanism.  
XFCE  
31  
0
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Register Descriptions  
13.4.25 Receive Descriptor Base Address Low  
RDBAL (02800h;R/W)  
This register contains the lower bits of the 64-bit descriptor base address. The four low-order  
register bits are always ignored. The Receive Descriptor Base Address must point to a 16-byte  
aligned block of data.  
Table 13-70. RDBAL Register Bit Description  
31  
4
3
0
RDBAL  
0
Initial  
Value  
Field  
Bit(s)  
3:0  
31:4  
Description  
0
0b  
Ignored on writes. Returns 0b on reads.  
Receive Descriptor Base Address Low.  
RDBAL  
X
13.4.26 Receive Descriptor Base Address High  
RDBAH (02804h; R/W)  
This register contains the upper 32 bits of the 64-bit Descriptor Base Address.  
Table 13-71. RDBAH Register Bit Description  
31  
0
RDBAH  
Initial  
Value  
Field  
RDBAH  
Bit(s)  
31:0  
Description  
X
Receive Descriptor Base Address [63:32]  
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Register Descriptions  
13.4.27 Receive Descriptor Length  
RDLEN (02808h; R/W)  
This register determines the number of bytes allocated to the circular receive descriptor buffer. This  
value must be 128-byte aligned (the maximum cache line size). Since each descriptor is 16 bytes in  
length, the total number of receive descriptors is always a multiple of eight.  
Table 13-72. RDLEN Register Bit Description  
31  
20 19  
7 6  
0
Reserved  
LEN  
0
Initial  
Value  
Field  
Bit(s)  
6:0  
Description  
Zero value  
Zero  
LEN  
0b  
Ignore on write. Reads back as 0b.  
Receive Descriptor length  
Provides the number of receive descriptors (in a multiple of eight).  
19:7  
0b  
0b  
Reserved  
Reserved  
31:20  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
13.4.28 Receive Descriptor Head  
RDH (02810h; R/W)  
This register contains the head pointer for the receive descriptor buffer. The register points to a 16-  
byte datum. Hardware controls the pointer. The only time that software should write to this register  
is after a reset (RCTL.RST or CTRL.RST) and before enabling the receiver function (RCTL.EN).  
If software were to write to this register while the receive function was enabled, the on-chip  
descriptor buffers can be invalidated and other indeterminate operations might result. Reading the  
descriptor head to determine which buffers are finished is not reliable.  
Table 13-73. RDH Register Bit Description  
31  
16 15  
0
Reserved  
RDH  
Initial  
Value  
Field  
Bit(s)  
Description  
RDH  
15:0  
31:16  
0b  
0b  
Receive Descriptor Head.  
Reserved. Should be written with 0b for future compatibility.  
Reads as 0b.  
Reserved  
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Register Descriptions  
13.4.29 Receive Descriptor Tail  
RDT (02818h;R/W)  
This register contains the tail pointers for the receive descriptor buffer. The register points to a 16-  
byte datum. Software writes the tail register to add receive descriptors to the hardware free list for  
the ring.  
Table 13-74. RDT Register Bit Description  
31  
16 15  
0
Reserved  
RDT  
Initial  
Value  
Field  
Bit(s)  
Description  
RDT  
15:0  
0b  
Receive Descriptor Tail.  
Reserved  
Reserved  
31:16  
0b  
Reads as 0b.  
Should be written with 0b for future compatibility.  
13.4.30 Receive Delay Timer Register  
RDTR (02820h; R/W)  
This register is used to delay interrupt notification for the receive descriptor ring. Delaying  
interrupt notification helps maximize the number of receive packets serviced by a single interrupt.  
Warning: It is strongly recommended that the Delay Timer field of this register not be used. For any  
application requiring an interrupt moderation mechanism, it is recommended that the Interrupt  
Throttling Register (ITR) be used instead. ITR provides a more direct interrupt solution than  
RDTR. In addition, Intel software device drivers use ITR instead of RDTR. Refer to the 82546EB  
Gigabit Ethernet Controller Specification Update or 82546GB Gigabit Ethernet Controller  
Specification Update for additional details.  
Table 13-75. RDTR Register Bit Description  
31 30  
16 15  
0
FPD  
Reserved  
Delay Timer  
Initial  
Value  
Field  
Bit(s)  
15:0  
Description  
Delay Timer  
Reserved  
0b  
Receive delay timer measured in increments of 1.024 s.  
30:16  
31  
0b  
0b  
Reserved. Reads as 0b.  
Flush partial descriptor block when set to 1b; ignore otherwise.  
Reads 0b (self-clearing).  
FPD  
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Register Descriptions  
This feature operates by initiating a countdown timer upon successfully receiving each packet to  
system memory. If a subsequent packet is received BEFORE the timer expires, the timer is re-  
initialized to the programmed value and re-starts its countdown. If the timer expires due to NOT  
having received a subsequent packet within the programmed interval, pending receive descriptor  
writebacks are flushed and a receive timer interrupt is generated.  
Setting the value to 0b represents no delay from a receive packet to the interrupt notification, and  
results in immediate interrupt notification for each received packet.  
Writing this register with FPD set initiates an immediate expiration of the timer, causing a  
writeback of any consumed receive descriptors pending writeback, and results in a receive timer  
interrupt in the ICR.  
Receive interrupts due to a Receive Absolute Timer (RADV) expiration cancels a pending RDTR  
interrupt. The RDTR countdown timer is reloaded but halted, so as to avoid generation of a  
spurious second interrupt after the RADV has been noted, but might be restarted by a subsequent  
received packet.  
13.4.31 Receive Interrupt Absolute Delay Timer1  
RADV (0282Ch; RW)  
Warning: It is strongly recommended that the Delay Timer field of this register not be used. For any  
application requiring an interrupt moderation mechanism, it is recommended that the Interrupt  
Throttling Register (ITR) be used instead. ITR provides a more direct interrupt solution than  
RADV. In addition, Intel software device drivers use ITR instead of RADV. Refer to the 82546EB  
Gigabit Ethernet Controller Specification Update or 82546GB Gigabit Ethernet Controller  
Specification Update for additional details.  
31  
30  
16  
15  
0
Reserved  
Delay Timer  
Initial  
Value  
Field  
Bit(s)  
Description  
Receive absolute delay timer measured in increments of 1.024 s (0b =  
Delay Timer  
Reserved  
15:0  
31:16  
0b  
0b  
disabled).  
Reserved. Reads as 0b.  
If the packet delay timer is used to coalesce receive interrupts, the Ethernet controller ensures that  
when receive traffic abates, an interrupt is generated within a specified interval of no receives.  
During times when receive traffic is continuous, it may be necessary to ensure that no receive  
remains unnoticed for too long an interval. This register can be used to ENSURE that a receive  
interrupt occurs at some predefined interval after the first packet is received.  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
When this timer is enabled, a separate absolute countdown timer is initiated upon successfully  
receiving each packet to system memory. When this absolute timer expires, pending receive  
descriptor writebacks are flushed and a receive timer interrupt is generated.  
Setting this register to 0b disables the absolute timer mechanism (the RDTR register should be  
used with a value of 0b to cause immediate interrupts for all receive packets).  
Receive interrupts due to a Receive Packet Timer (RDTR) expiration cancels a pending RADV  
interrupt. If enabled, the RADV countdown timer is reloaded but halted, so as to avoid generation  
of a spurious second interrupt after the RDTR has been noted.  
13.4.32 Receive Small Packet Detect Interrupt1  
RSRPD (02C00h; R/W)  
31  
12  
11  
SIZE  
0
Reserved  
Initial  
Value  
Field  
Bit(s)  
Description  
If the interrupt is enabled, any receive packet of size SIZE asserts  
an Interrupt. SIZE is specified in bytes and includes the headers and  
the CRC. It does not include the VLAN header in size calculation if it  
is stripped.  
SIZE  
11:0  
0b  
Reserved  
31:12  
X
Reserved. Reads as 0b.  
13.4.33 Transmit Control Register  
TCTL (00400h;R/W)  
This register controls all transmit functions for the Ethernet controller.  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
Table 13-76. TCTL Register Bit Description  
31  
26 25  
22 21  
12 11  
4 3  
0
Reserved  
CNTL Bits  
COLD  
CT  
CNTL Bits  
Initial  
Value  
Field  
Bit(s)  
Description  
Reserved  
Write as 0b for future compatibility.  
Reserved  
EN  
0
1
0b  
Transmit Enable  
The transmitter is enabled when this bit is set to 1b. Writing 0b to  
this bit stops transmission after any in progress packets are sent.  
Data remains in the transmit FIFO until the device is re-enabled.  
Software should combine this operation with reset if the packets in  
the TX FIFO should be flushed.  
0b  
0b  
Reserved  
Reads as 0b.  
Should be written to 0b for future compatibility.  
Reserved  
2
3
Pad Short Packets  
0b = Do not pad.  
1b = Pad short packets.  
Padding makes the packet 64 bytes long. The padding content is  
data.  
When the Pad Short Packet feature is disabled, the minimum  
packet size the Ethernet controller can transfer to the host is 32  
bytes long.  
PSP  
0b  
This feature is not the same as Minimum Collision Distance  
(TCTL.COLD).  
Collision Threshold  
This determines the number of attempts at re-transmission prior to  
giving up on the packet. The Ethernet back–off algorithm is  
implemented and clamps to the maximum value after 16 retries. It  
only has meaning in half-duplex operation. Recommended value –  
0Fh.  
CT  
11:4  
0b  
Collision Distance  
Specifies the minimum number of byte times that must elapse for  
proper CSMA/CD operation. Packets are padded with special  
symbols, not valid data bytes. Hardware checks this value and  
padded packets even in full-duplex operation.  
Recommended value:  
COLD  
21:12  
0b  
Half-Duplex – 512-byte time (200h)  
Full-Duplex – 64-byte time (40h)  
Note: 10/100 half-duplex - 64 - 68 (40h to 44h) byte times for the  
82541xx and 82547GI/EI only.  
Software XOFF Transmission  
When set to 1b, the Ethernet controller schedules the transmission  
of an XOFF (PAUSE) frame using the current value of the PAUSE  
timer (FCTTV.TTV). This bit self-clears upon transmission of the  
XOFF frame. This bit is valid only in Full-Duplex mode of  
operation. Software should not set this bit while the Ethernet  
controller is configured for half-duplex operation.  
SWXOFF  
22  
0b  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Reserved  
Reserved  
23  
0b  
Read as 0b.  
Should be written with 0b for future compatibility.  
Re-transmit on Late Collision  
When set, enables the Ethernet controller to re-transmit on a late  
collision event.  
The collision window is speed dependent. For example, 64 bytes  
for 10/100 Mb/s and 512 bytes for 1000Mb/s operation. If a late  
collision is detected when this bit is disabled, the transmit function  
assumes the packet is successfully transmitted.  
The RTLC bit is ignored in full-duplex mode.  
RTLC  
24  
0b  
No Re-transmit on underrun (82544GC/EI only)  
If this bit is set, the 82544GC/EI does not re-transmit packets that  
initially had an underrun.  
This function is accomplished by waiting for the entire packet to be  
buffered in the transmit FIFO before the controller attempts to re-  
transmit a packet that previously encountered an underrun. This  
operation guarantees only one underrun can occur per packet.  
This is a reserved bit for all other Ethernet controllers and should  
be written with 0b for future compatibility.  
NRTU1  
Reserved  
25  
0b  
0b  
Reserved  
Read as 0.  
Reserved  
31:26  
Should be written with 0b for future compatibility.  
1.  
82544GC/EI only.  
For the 82541xx and 82547GI/EI, carrier extension (through the TCTL  
field) provides a  
COLD  
method to increase the duration of the carrier event to a minimum usable duration in order to meet  
a 200 m collision domain objective, even though half-duplex operation is impractical at Gigabit.  
Packets that are signaled from the CSMA/CD layer that do not meet the minimum slot time of 512  
bytes have extension bytes appended to them in order to meet this minimum slot time requirement.  
The extension bytes are defined within the context of the frame encapsulation discussion of the  
802.3z standard and are recognized by 802.3z compliant devices. Refer to Figure 13-1  
Preamble  
SFD  
DA  
SA  
T/L  
Data/Pad  
FCS  
Extension  
Minimum Frame Size  
Slot Time  
arrier Event  
Duration of C  
Figure 13-1. Carrier Extended Frame Format (82541xx and 82547GI/EI)  
13.4.34 Transmit IPG Register  
TIPG (00410;R/W)  
This register controls the IPG (Inter Packet Gap) timer for the Ethernet controller.  
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Register Descriptions  
Table 13-77. TIPG Register Bit Description  
31  
30 29  
20 19  
10  
9
0
Reserved  
IPGR2  
IPGR1  
IPGT  
Initial  
Value  
Field  
Bit(s)  
Description  
IPG Transmit Time  
Specifies the IPG time for back-to-back packet transmissions  
Measured in increments of the MAC clock:  
•
•
•
8 ns MAC clock when operating @ 1 Gbps.  
80 ns MAC clock when operating @ 100 Mbps.  
800 ns MAC clock when operating @ 10 Mbps.  
To calculate the actual IPG value for TBI applications, a value of  
10 (6 for the 82544GC/EI) should be added to the IPGT value.  
For the IEEE 802.3 standard IPG value of 96-bit time, the value  
that should be programmed into IPGT is 10 (6 for the 82544GC/  
EI).  
IPGT  
9:0  
X
To calculate the IPG value for 10/100/1000BASE-T applications,  
a value of four should be added to the IPGT value as four clocks  
are used by the MAC as internal overhead. The value that  
should be programmed into IPGT is 10 (8 for the 82544GC/EI).  
These values are recommended to assure that the minimum  
IPG gap is met under all synchronization conditions.  
IPG Receive Time 1  
Specifies the length of the first part of the IPG time for non back-  
to-back transmissions. During this time, the internal IPG counter  
restarts if any carrier event occurs. Once the time specified in  
IPGR1 has elapsed, carrier sense does not affect the IPG  
counter.  
According to the IEEE802.3 standard, IPGR1 should be 2/3 of  
IPGR2 value.  
IPGR1  
19:10  
X
Measured in increments of the MAC clock:  
•
8 ns MAC clock when operating @ 1 Gbps (82544GC/EI  
only).  
•
•
80 ns MAC clock when operating @ 100 Mbps  
800 ns MAC clock when operating @ 10 Mbps.  
For IEEE 802.3 minimum IPG value of 96-bit time, the value that  
should be programmed into IPGR1 is eight.  
IPGR1 is significant only in half-duplex mode of operation.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
IPG Receive Time 2  
Specifies the total length of the IPG time for non back-to-back  
transmissions.  
Measured in increments of the MAC clock:  
•
8 ns MAC clock when operating @ 1 Gbps (82544GC/EI  
only).  
•
•
80 ns MAC clock when operating @ 100 Mbps  
800 ns MAC clock when operating @ 10 Mbps.  
IPGR2  
29:20  
X
In order to calculate the actual IPG value, a value of six should  
be added to the IPGR2 value as six MAC clocks are used by the  
MAC for synchronization and internal engines.  
For the IEEE 802.3 standard IPG value of 96-bit time, the value  
that should be programmed into IPGR2 is six (total IPG delay of  
12 MAC clock cycles) According to the IEEE802.3 standard,  
IPGR1 should be 2/3 of IPGR2 value.  
IPGR2 is significant only in half-duplex mode of operation.  
Reserved  
Reserved  
31:30  
X
Read as 0b.  
Should be written with 0b for future compatibility.  
13.4.35 Adaptive IFS Throttle - AIT  
AIFS (00458;R/W)  
This register throttles back-to-back transmissions in the transmit packet buffer and delays their  
transfer to the CSMA/CD transmit function. As a result, it can be used to delay the transmission of  
back-to-back packets on the wire.  
For the 82544GC/EI, this register can be used to increase the IPG value between transmitting  
back-to-back packets on the wire and between frames while in half-duplex mode.  
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Register Descriptions  
Table 13-78. AIFS Register Bit Description  
31  
16 15  
0
Reserved  
Adaptive IFS  
Initial  
Value  
Field  
Bit(s)  
Description  
Adaptive IFS Value (82544GC/EI only)  
Adaptive IFS throttles back-to-back transmissions in the  
transmit packet buffer and delays their transfer to the CSMA/CD  
transmit function. Normally, this register should be set to 0b.  
However, if additional delay is desired between back-to-back  
transmit packets, then this register can be set with a value  
greater than zero (0). This feature can be helpful in high collision  
half-duplex environments.  
In order for AIFS to take effect it should be larger than the  
minimum IFS value defined in IEEE 802.3 standard.  
AIFS has no effect on transmissions that occur immediately  
after receives or transmissions that are not back-to-back. In  
addition, it has no effect on re-transmission timing (re-  
transmission after collisions).  
AIFS  
15:0  
0b  
The AIFS programming value is in units of 8 ns (TX_CLK), and  
is 16 bits wide, thus providing greater flexibility and maximum  
delay value comparing TIPG.IPGT. The AIFS value is additive to  
the TIPG.IPGT value.  
Adaptive IFS Value (all remaining Ethernet controllers)  
This value is in units of 8 ns.  
Reserved  
Should be written with 0b.  
Reserved  
31:16  
0b  
13.4.36 Transmit Descriptor Base Address Low  
TDBAL (03800h; R/W)  
This register contains the lower bits of the 64-bit transmit Descriptor base address. The base  
register indicates the start of the circular transmit descriptor queue. Since each descriptor is 16 bits  
in length, the lower four bits are ignored as the Transmit Descriptor Base Address must point to a  
16-byte aligned block of data.  
Table 13-79. TDBAL Register Bit Description  
31  
4 3  
0
TDBAL  
0
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Zero Value  
ZERO  
3:0  
0b  
This field is ignored on write and reads as 0b.  
Transmit Descriptor Base Address Low [31:4]  
This register indicates lower 32 bits of the start address for the  
transmit descriptor ring buffer.  
TDBAL  
31:4  
X
13.4.37 Transmit Descriptor Base Address High  
TDBAH (03804h; R/W)  
This register contains the upper 32 bits of the 64-bit transmit Descriptor base address.  
Table 13-80. TDBAH Register Bit Description  
31  
0
TDBAH  
Initial  
Value  
Field  
Bit(s)  
Description  
Transmit Descriptor Base Address [63:32]  
This register indicates upper 32 bits of the start address for the  
transmit descriptor ring buffer.  
TDBAH  
31:0  
X
13.4.38 Transmit Descriptor Length  
TDLEN (03808h; R/W)  
This register determines the number of bytes allocated to the transmit descriptor circular buffer.  
This value must be a multiple of 128 bytes (the maximum cache line size). Since each descriptor is  
16 bits in length, the total number of receive descriptors is always a multiple of eight.  
Table 13-81. TDLEN Register Bit Description  
31  
20 19  
7 6  
0
Reserved  
LEN  
0
Initial  
Value  
Field  
ZERO  
Bit(s)  
6:0  
Description  
Ignore on write. Reads back as 0b.  
0b  
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Register Descriptions  
Descriptor Length.  
LEN  
19:7  
0b  
0b  
Number of bytes allocated to the transmit descriptor circular  
buffer.  
Reserved  
Reserved  
31:20  
Reads as 0b. Should be written with 0b for future compatibility.  
13.4.39 Transmit Descriptor Head  
TDH (03810h; R/W)  
This register contains the head pointer for the transmit descriptor ring. It holds a value that is an  
offset from the base, and indicates the in–progress descriptor. It points to a 16-byte datum.  
Hardware controls this pointer. The only time that software should write to this register is after a  
reset (TCTL.RST or CTRL.RST) and before enabling the transmit function (TCTL.EN). If  
software were to write to this register while the transmit function was enabled, the on-chip  
descriptor buffers can be invalidated and indeterminate operation can result. Reading the transmit  
descriptor head to determine which buffers have been used (and can be returned to the memory  
pool) is not reliable.  
Table 13-82. TDH Register Bit Description  
31  
16 15  
0
Reserved  
TDH  
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Register Descriptions  
Initial  
Value  
Field  
TDH  
Bit(s)  
15:0  
31:16  
Description  
0b  
0b  
Transmit Descriptor Head  
Reserved  
Reserved  
Reads as 0b. Should be written with 0b for future compatibility.  
13.4.40 Transmit Descriptor Tail  
TDT (03818h; R/W)  
This register contains the tail pointer for the transmit descriptor ring. It holds a value that is an  
offset from the base, and indicates the location beyond the last descriptor hardware can process.  
This is the location where software writes the first new descriptor. It points to a 16-byte datum.  
Software writes the tail pointer to add more descriptors to the transmit ready queue. Hardware  
attempts to transmit all packets referenced by descriptors between head and tail.  
Table 13-83. TDT Register Bit Description  
31  
16 15  
0
Reserved  
TDT  
Initial  
Value  
Field  
Bit(s)  
Description  
TDT  
15:0  
31:16  
0b  
0b  
Transmit Descriptor Tail  
Reserved  
Reserved  
Reads as 0b. Should be written to 0b for future compatibility.  
13.4.41 Transmit Interrupt Delay Value  
TIDV (03820h; R/W)  
This register contains the transmit interrupt delay value. It determines the amount of time that  
elapses between writing back a descriptor that has Report Status (RS) [or Report Packet Sent (RPS)  
for the 82544GC/EI] and Interrupt Delay Enable (IDE) set in the transmit descriptor and when the  
IMS.TXDW (Transmit Descriptor Written Back) interrupt bit is set. Counts are in units of 1.024  
s. A value of 0b is not allowed. The TIDV value is used to force timely write–back of descriptors  
as well. The first packet after timer initialization starts the timer. Timer expiration flushes any  
accumulated descriptors and sets an interrupt event (TXDW).  
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Register Descriptions  
Table 13-84. TIDV Register Bit Description  
31  
16 15  
0
Reserved  
IDV  
Initial  
Value  
Field  
Bit(s)  
Description  
Interrupt Delay Value  
Counts in units of 1.024 s. A value of 0bis not allowed.  
IDV  
15:0  
X
Reserved  
Reserved  
31:16  
0b  
Reads as 0b. Should be written to 0b for future compatibility.  
13.4.42 TX DMA Control (82544GC/EI only)  
TXDMAC (03000h; R/W)  
This register controls the transmit DMA pre-fetching and preemption abilities.  
Table 11-85. TXDMAC Register Bit Description  
31  
1
0
Reserved  
DPP  
Initial  
Value  
Field  
Bit(s)  
Description  
Disable packet prefetching  
When set, prevents the Ethernet controller from starting a  
transmit descriptor data fetch before it has finished processing  
the previous descriptor. In general, performance increases  
when this bit is set to 0b.  
DPP  
0
1
0
Reserved  
Reserved  
31:1  
Reads as 0b. Should be written to 0b for future compatibility.  
13.4.43 Transmit Descriptor Control  
TXDCTL (03828h; R/W)  
This register controls the fetching and write back of transmit descriptors. The three threshold  
values provided are used to determine when descriptors are read from and written to host memory.  
The values can be in units of cache lines or descriptors (each descriptor is 16 bytes).  
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Register Descriptions  
Table 13-86. TXDCTL Register Bit Description  
31  
LWTHRESH  
RSV1  
25  
24  
23 22 21  
16 15 14 13  
8 7  
6 5  
0
GRAN RSV  
WTHRESH  
RSV  
HTHRESH  
RSV  
PTHRESH  
1.  
82544GC/EI only.  
Initial  
Value  
Field  
Bit(s)  
Description  
Prefetch Threshold  
Used to control when a pre-fetch of descriptors is considered.  
This threshold refers to the number of valid, unprocessed  
transmit descriptors the Ethernet controller has in its on-chip  
buffer. If this number drops below PTHRESH, the algorithm  
considers prefetching descriptors from host memory. This fetch  
does not happen unless there are at least TXDCTL.HTHRESH  
valid descriptors in host memory to fetch. Value of PTHRESH  
can be in either cache line units, or based on number of  
descriptors based on TXDCTL.GRAN.  
PTHRESH  
5:0  
0b  
0b  
0b  
0b  
Reserved  
Reserved  
HTHRESH  
Reserved  
7:6  
Reads as 0b. Should be written as 0b for future compatibility.  
Host Threshold  
Provides the threshold of the valid descriptors in host memory A  
descriptor prefetch is performed each time enough valid  
descriptors (TXDCTL.HTHRESH) are available in host memory,  
no other DMA activity of greater priority is pending (descriptor  
fetches and write backs or packet data transfers) and the number  
of transmit descriptors the Ethernet controller has on its on-chip  
buffers drops below TXDCTL.PTHRESH. The value of  
HTHRESH can be in either cache line units, or based on number  
of descriptors based on TXDCTL.GRAN.  
15:8  
15:14  
Reserved  
Reads as 0b. Should be written as 0b for future compatibility.  
Write Back Threshold  
WTHRESH controls the write back of processed transmit  
descriptors. This threshold refers to the number of transmit  
descriptors in the Ethernet controller’s on-chip buffer which are  
ready to be written back to host memory. In the absence of  
external events (explicit flushes), the write back occurs only after  
more than WTHRESH descriptors are available for write back.  
WTHRESH must contain a non-zero value to take advantage of  
the write back bursting capabilities of the Ethernet controller. A  
value of 0b causes the descriptors to be written back as soon as  
they are processed.  
WTHRESH  
21:16  
0b  
The value of WTHRESH can be in either cache line units, or  
based on number of descriptors based on RXDCTL.GRAN.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Reserved  
Reserved  
23:22  
0b  
Reads as 0b. Should be written as 0b for future compatibility.  
Granularity  
Set the values of PTHRESH, HTHRESH and WTHRESH in units  
of cache lines or descriptors (each descriptor is 16 bytes)  
1b = Descriptor granularity.  
GRAN  
24  
0b  
0b = Cache line granularity.  
Transmit descriptor Low Threshold  
Interrupt asserted when the number of descriptors pending  
service in the transmit descriptor queue (processing distance  
from the TDT) drops below this threshold.  
LWTHRESH1  
31:25  
0h  
1.  
Not applicable to the 82544GC/EI.  
Since write back of transmit descriptors is optional (under the control of RS bit in the descriptor),  
not all processed descriptors are counted with respect to WTHRESH. Descriptors start accumu-  
lating after a descriptor with RS (or RPS for the 82544GC/EI) is set. Furthermore, with transmit  
descriptor bursting enabled, some descriptors are written back that did not have RS (or RPS for the  
82544GC/EI) set in their respective descriptors.  
LWTHRESH (not applicable to the 82544GC/EI) controls the number of pre-fetched transmit  
descriptors at which a transmit descriptor-low interrupt (ICR.TXD_LOW) is reported. This can  
enable software to operate more efficiently by maintaining a continuous addition of transmit work,  
interrupting only when the hardware nears completion of all submitted work. LWTHRESH  
specifies a multiple of eight descriptors. An interrupt is asserted when the number of descriptors  
available transitions from (threshold level=8*LWTHRESH)+1 to (threshold  
level=8*LWTHRESH). Setting this value to 0b causes this interrupt to be generated only when the  
transmit descriptor cache becomes completely empty.  
13.4.44 Transmit Absolute Interrupt Delay Value1  
TADV (0382Ch; RW)  
31  
16  
15  
0
Reserved  
IDV  
Initial  
Value  
Field  
Bit(s)  
Description  
Interrupt Delay Value  
Counts in units of 1.024 s. (0b = disabled)  
IDV  
15:0  
31:16  
0b  
0b  
Reserved  
Reads as 0b. Should be written to 0b for future compatibility.  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
The transmit interrupt delay timer (TIDV) can be used to coalesce transmit interrupts. However, it  
might be necessary to ensure that no completed transmit remains unnoticed for too long an interval  
in order ensure timely release of transmit buffers. This register can be used to ENSURE that a  
transmit interrupt occurs at some predefined interval after a transmit is completed. Like the  
delayed-transmit timer, the absolute transmit timer ONLY applies to transmit descriptor operations  
where (a) interrupt-based reporting is requested (RS set) and (b) the use of the timer function is  
requested (IDE is set).  
This feature operates by initiating a countdown timer upon successfully transmitting the buffer.  
When the timer expires, a transmit-complete interrupt (ICR.TXDW) is generated. The occurrence  
of either an immediate (non-scheduled) or delayed transmit timer (TIDV) expiration interrupt halts  
the TADV timer and eliminates any spurious second interrupts.  
Setting the value to 0b disables the transmit absolute delay function. If an immediate (non-  
scheduled) interrupt is desired for any transmit descriptor, the descriptor IDE should be set to 0b.  
13.4.45  
TCP Segmentation Pad And Minimum Threshold  
TSPMT (03830h; RW)  
This register specifies fields affecting the Ethernet controller behavior during TCP Segmentation  
operations. Values are specified in bytes. For normal (non TCP Segmentation) operations, the  
Ethernet controller’s transmit DMA never begins servicing an individual data descriptor unless the  
transmit Packet Buffer has sufficient room to accept all of the data associated with the descriptor.  
However, for TCP Segmentation operations, it might be desirable to use a data descriptor that  
refers to a larger contiguous buffer in host memory than is actually allocated for the transmit Packet  
Buffer. For TCP segmentation, then, the transmit DMA is able to initiate smaller transfers than the  
entire descriptor’s data length field.  
31  
16  
15  
0
TSPBP  
TSMT  
Initial  
Value  
Field  
Bit(s)  
Description  
TSMT  
15:0  
31:16  
0400h  
0100h  
TCP Segmentation Minimum Transfer  
TSPBP  
TCP Segmentation Packet Buffer Padding  
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Register Descriptions  
When performing TCP segmentation, the packet prototype header initially transferred by DMA is  
stored internally and updated as each packet of the TCP segmentation operation is composed. As  
data for subsequent TCP segments is DMA’d into the Ethernet controller, the frame header for each  
segment is dynamically inserted in front of the frame payload data stream prior to being written to  
the packet buffer. In order to obtain the most efficient use of burst DMA operations, the transmit  
DMA attempts to fetch as much data from a descriptor as possible, rather than limiting itself to  
bursting each data segment individually. However, to do this, sufficient packet buffer space must  
be reserved to account for all headers are inserted into the fetched data stream, as the burst might  
span multiple data segments. The calculation of how much packet buffer space should be reserved  
is dependent on the MSS being used, the maximum-sized data buffer pointed to by a descriptor,  
and the current header size. This calculation is left to software to pre-calculate for the worst-case  
usage. The TSPBP register allows configuration of this buffer space that must be reserved as “pad”  
for worst-case header insertion. To ensure that this value does not prevent descriptors from being  
serviced at all, it is necessary that the transmit packet buffer allocation should be larger than the  
sum of (maximum TCP HDRLEN + maximum MSS + TMPBP + 80 bytes).  
Because the DMA attempts to issue burst fetches for a much data as possible, it is possible for the  
transmit DMA to cause the transmit packet buffer to approach fullness (less the pad specified).  
However, if the packet buffer empties slightly, the transmit DMA could initiate a series of small  
transfers. To further optimize the efficiency of the transmit DMA during TCP segmentation  
operation, the TSMT register allows configuration of the minimum number of bytes that the DMA  
should attempt to transfer in a single burst operation. The transmit DMA uses this value to refrain  
from issuing a burst read until at least TSMT bytes of data from the current data descriptor can be  
stored in the packet buffer. This check is ignored if, after a series of DMA operations, the  
descriptor contains a smaller number of unfetched data bytes. To ensure that this minimum  
threshold does not prevent descriptors from being serviced at all, it is necessary that the transmit  
packet buffer allocation should be larger than the sum of (TSMT + TSPBP + 80 bytes). To ensure  
compliance with PCI-X specifications, this value should not be programmed to exceed 4 KB (the  
largest single-burst transfer allowed by PCI-X).  
The transmit DMA further refrains from initiating service of a new data descriptor unless sufficient  
packet buffer space exists to at least fetch a full data segment or complete a partially-fetched  
segment.  
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Register Descriptions  
13.4.46 Receive Descriptor Control  
RXDCTL (02828h; R/W)  
This register controls the fetching and write-back of receive descriptors. The three threshold values  
are used to determine when descriptors are read from and written to host memory. The values can  
be in units of cache lines or descriptors (each descriptor is 16 bytes) based on the GRAN flag. If  
GRAN = 0b (specifications are in cache-line granularity), the thresholds specified (based on the  
cacheline size specified in the PCI header CLS field) must not represent greater than 31  
descriptors.  
Table 13-87. RXDCTL Register Bit Description  
31  
25  
24  
23 22 21  
16 15 14 13  
8 7  
6 5  
0
Reserved  
GRAN RSV  
WTHRESH  
RSV  
HTHRESH  
RSV  
PTHRESH  
Initial  
Value  
Field  
Bit(s)  
Description  
Prefetch Threshold  
Used to control when a prefetch of descriptors is considered. This  
threshold refers to the number of valid, unprocessed receive  
descriptors the Ethernet controller has in its on-chip buffer. If this  
number drops below PTHRESH, the algorithm considers  
prefetching descriptors from host memory. This fetch does not  
happen unless there are at least RXDCTL.HTHRESH valid  
descriptors in host memory to fetch. Value of PTHRESH can be in  
either cache line units, or based on number of descriptors based  
on RXDCTL.GRAN.  
PTHRESH  
5:0  
0b  
0b  
0b  
0b  
Reserved  
Reads as 0b.  
Should be written as 0b for future compatibility.  
RSV  
7:6  
Host Threshold  
Provides the threshold of the valid descriptors in host memory.  
A descriptors prefetch is performed each time enough valid  
descriptors (TXDCTL.HTHRESH) are available in host memory,  
no other DMA activity of greater priority is pending (descriptor  
fetches and write backs or packet data transfers) and the number  
of receive descriptors the Ethernet controller has on its on-chip  
buffers drops below RXDCTL.PTHRESH. Value of HTHRESH  
can be in either cache line units, or based on number of  
descriptors based on RXDCTL.GRAN.  
HTHRESH  
13:8  
Reserved  
Reads as 0b.  
RSV  
15:14  
Should be written as 0b for future compatibility.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Write Back Threshold  
WTHRESH controls the write back of processed receive  
descriptors. This threshold refers to the number of receive  
descriptors in the Ethernet controller’s on-chip buffer which are  
ready to be written back to host memory. In the absence of  
external events (explicit flushes), the write back occurs only after  
more than WTHRESH descriptors are available for write back.  
WTHRESH must contain a non-zero value to take advantage of  
the write back bursting capabilities of the Ethernet controller.  
A value of 1b causes the descriptors to be written back as soon  
as one cache line is available. A value of WTHRESH can be in  
either cache line units, or based on number of descriptors based  
on RXDCTL.GRAN.  
WTHRESH  
21:16  
1b  
Reserved  
RSV  
23:22  
24  
0b  
1b  
0b  
Reads as 0b.  
Should be written as 0b for future compatibility.  
Granularity  
Set the values of PTHRESH, HTHRESH and WTHRESH in units  
of cache lines or descriptors (each descriptor is 16 bytes)  
0b = Cache line granularity.  
GRAN  
Reserved  
1b = Descriptor granularity.  
Reserved  
Reads as 0b.  
31:25  
Should be written as 0b for future compatibility.  
13.4.47 Receive Checksum Control  
RXCSUM (05000h; R/W)  
The Receive Checksum Control register controls the receive checksum offloading features of the  
Ethernet controller. The Ethernet controller supports the offloading of three receive checksum  
calculations: the Packet Checksum, the IP Header Checksum, and the TCP/UDP Checksum.  
The frame types that are supported:  
• Ethernet II  
• Ethernet SNAP  
Table 13-88. RXCSUM Register Bit Description  
31:11  
10  
9
8
7
0
RSV  
IPV6OFL1  
TUOFLD IPOFLD  
PCSS  
1.  
Not applicable to the 82544GC/EI.  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Packet Checksum Start  
Controls the starting byte for the Packet Checksum  
calculation. The Packet Checksum is the one’s complement  
over the receive packet, starting from the byte indicated by  
RXCSUM.PCSS (0b corresponds to the first byte of the  
packet), after stripping. For example, for an Ethernet II frame  
encapsulated as an 802.3ac VLAN1 packet and with  
RXCSUM.PCSS set to 14, the packet checksum would  
include the entire encapsulated frame, excluding the 14-byte  
Ethernet header (DA,SA,Type/Length) and the 4-byte VLAN  
tag. The Packet Checksum does not include the Ethernet  
CRC if the RCTL.SECRC bit is set. Software must make the  
required offsetting computation (to back out the bytes that  
should not have been included and to include the pseudo-  
header) prior to comparing the Packet Checksum against the  
TCP checksum stored in the packet.  
PCSS  
7:0  
0b  
IP Checksum Off-load Enable  
RXCSUM.IPOFLD is used to enable the IP Checksum  
offloading feature. If RXCSUM.IPOFLD is set to 1b, the  
Ethernet controller calculates the IP checksum and indicates  
a pass/fail indication to software through the Checksum Error  
bit (CSE) in the ERROR field to the receive descriptor. If both  
RXCSUM.IPOFLD and RXCSUM.TUOFLD are set, the  
Checksum Error bit (CSE) is set if either checksum was  
incorrect. If neither RSCSUM.IPOFLD nor  
IPOFLD  
8
0b  
RXCSUM.TUOFLD is set, the Checksum Error bit (CSE) is  
be 0b for all packets.  
TCP/UDP Checksum Off-load Enable  
RXCSUM.TUOFL is used to enable the TCP/UDP Checksum  
off-loading feature. When set to 1b, the Ethernet controller  
calculates the TCP or UDP checksum and indicate a pass/fail  
indication to software through the Checksum Error bit (CSE).  
If both RXCSUM.TUOFLD and RXCSUM.TUOFLD are set,  
the Checksum Error bit (CSE) is set if either checksum was  
incorrect. If neither RXCSUM.IPOFLD nor  
TUOFLD  
9
0b  
RXCSUM.TUOFLD is set, the Checksum Error bit (CSE) is  
0b for all packets.  
IPv6 Checksum Offload Enable  
If IPV6OFL is set to 1b, hardware parses IPv6 headers when  
parsing a receive packet. This applies to checksum offloading  
only.  
IPV6OFL2  
Reserved  
10  
0b  
0b  
Reserved  
31:11  
Reads as 0b. Should be written with 0b for future  
compatibility.  
1.  
2.  
Not applicable to the 82541ER.  
Not applicable to the 82544GC/EI.  
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Register Descriptions  
13.5  
Filter Registers  
This section contains detailed descriptions for those registers associated with the Ethernet  
controller’s address filter capabilities.  
13.5.1  
Multicast Table Array  
MTA[127:0] (05200h-053FCh; R/W)  
The multicast table array is a way to extend address filtering beyond the 16 perfect in the Receive  
Address Register (RAR). Note that the MTA is an imperfect filter that allows you to filter on 4096  
similar addresses using a much smaller data structure than would be required to store all 4096  
addresses in a linear table such as a perfect filter.  
The Ethernet controller provides a 4096-bit vector multicast table array that is used when all the 16  
perfect filters in the Receive Address Registers (RAR) are used. There is one register per 32 bits of  
the Multicast Address Table for a total of 128 registers (thus the MTA[127:0] designation). The  
size of the word array depends on the number of bits implemented in the multicast address table.  
Software must mask to the desired bit on reads and supply a 32-bit word on writes. Accesses to this  
table must be 32-bit.  
Table 13-89. MTA Register Bit Description  
Initial  
Value  
Field  
Bit(s)  
Description  
Multicast bit vector specifying 32 bits in the multicast address filter  
table.  
MC Bit Vector  
31:0  
X
The operating system provides a list of addresses that it would like to respond to. The driver fills in  
the Receive Address Registers (RAR) first, as these are exact matching addresses. If the OS  
provides more than the 16 addresses available in RARs, the overflow is put into the MTA. The  
MTA does not match the exact address, but a subset of the address. Each address filtered on is  
represented by a single bit within the MTA table. Software needs to do the same calculations that  
hardware does when checking against the MTA, so it can program the appropriate bit in the MTA.  
When the hardware receives an address, it goes through the RARs, and if it does not find a match,  
it does the same calculations that are described below on the address that it was given and only  
checks one bit in the MTA. If that bit is set, it allows the packet to pass. If that bit is not set, it drops  
the packet.  
The calculation to find that bit is as follows (using the example of 12:34:56:78:9A:BCh):  
Check the RCTL bits 13:12 to see what they are set to. In this example it is 00h that means that  
we only look at bits 47:36. This corresponds to 0BC9h in the example address (assuming that  
in your example 12 is the least significant byte and 0BCh is the most significant byte). The  
way the address is stored in memory is the same that it would be going out on the wire, which  
is the least significant byte is the first on the wire, so it looks like this:  
BC:9A:78:56:34:12h so that the LSB (12) goes on the wire first. Breaking 0BC9h down into a  
word:  
0BC9h = 0000_1011_1100_1001b  
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Register Descriptions  
Of the 16 bits, look at bits 11:5, starting from zero. These seven bits corresponds to the row  
within the MTA table (the MTA has 128 rows which require seven bits to define). In the  
example, bits 11:5 are 1011110b. This corresponds to row 94.  
Of these 16 bits, count out the first five bits, again starting from bit zero. These first five bits  
correspond to the bit within the row (the MTA is 32 bits wide which require five bits to  
define). In the example this is 01001b. This corresponds to bit nine. This is the offset within  
the row.  
Therefore, software needs to set bit nine of row 94 in the MTA. If the OS removes this address  
from the filter list, software would need to clear this bit. This is the same bit that the hardware  
would check if it received a packet with an address of xx:xx:xx:xx:9x:BCh.  
Destination Address  
47:40 39:32 31:24 23:16 15:8  
7:0  
bank[1:0]  
Multicast Table  
Array 32 x 128  
(4096-bit vector)  
?
word  
pointer[11:5]  
...  
...  
bit  
pointer[4:0]  
Figure 13-2. Multicast Table Array  
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Register Descriptions  
13.5.2  
Receive Address Low  
RAL (05400h + 8*n; R/W)  
16 registers contain the lower bits of the 48-bit Ethernet address. All 32 bits are valid. Software can  
access the High and Low registers as a register pair if it can perform a 64-bit access to the PCI bus.  
The addresses stored in these registers are used for unicast/multicast address filtering.  
The first receive address register (RAL0, RAH0) is also used for exact match PAUSE frame  
checking (Valid PAUSE packet that is addressed to the station’s address). Therefore, RAL0 and  
RAH0 always should be used to store the individual Ethernet MAC address of the Ethernet  
controller.  
Table 13-90. RAL Register Bit Description  
31  
0
RAL  
Initial  
Value  
Field  
Bit(s)  
Description  
Receive address low  
Contains the lower 32-bit of the 48-bit Ethernet address.  
RAL0 should be used to store the lower 32-bit of the Ethernet  
controller’s Ethernet MAC address.  
RAL  
31:0  
X
13.5.3  
Receive Address High  
RAH (05404h + 8n; R/W)  
16 registers contain the upper bits of the 48-bit Ethernet address. The complete address is {RAH,  
RAL}. Software can access the High and Low registers as a register pair if it can perform a 64-bit  
access to the PCI bus. The addresses stored in these registers are used for unicast/multicast address  
filtering.  
The first receive address register (RAL0, RAH0) is also used for exact match Pause frame  
checking (Valid Pause packet that is addressed to the station’s address). Therefore, RAL0 and  
RAH0 always should be used to store the individual Ethernet MAC address of the Ethernet  
controller.  
Note: When writing to this register, always write low-to-high. When clearing this register, always clear  
high-to-low.  
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Register Descriptions  
Table 13-91. RAH Register Bit Description  
31 30  
18 17  
16 15  
0
AV  
Reserved  
AS  
RAH  
Initial  
Value  
Field  
Bit(s)  
Description  
Receive address High  
Contains the upper 16 bits of the 48-bit Ethernet address.  
RAH0 should be used to store the upper 16-bit of the Ethernet  
controller’s Ethernet MAC address.  
RAH  
15:0  
X
X
Address Select  
Selects how the address is to be used in the address filtering.  
00b = Destination address (required for normal mode)  
01b = Source address  
10b = Reserved  
11b = Reserved  
AS  
17:16  
30:18  
Reserved  
Reserved  
0b  
0b  
Should be written with 0b to ensure future compatibility.  
Reads as 0b.  
Address Valid  
Determines whether this address is compared against the  
incoming packet. When set, the address is valid and is  
compared against the incoming packet. When cleared, the  
address is invalid and is not compared against the received  
AV  
31  
packet. AV is only cleared by a PCI reset or software reset. This  
bit is unchanged by rx_reset.  
13.5.4  
VLAN Filter Table Array1  
VFTA[127:0] (05600h – 057FCh; R/W)  
The Ethernet controller provides a 4096-bit vector VLAN Filter table array. There is one register  
per 32 bits of the VLAN Filter Table, for a total of 128 registers (thus the VFTA[127:0]  
designation). The size of the word array depends on the number of bits implemented in the VLAN  
Filter table. Software must mask to the desired bit on reads, and supply a 32-bit word on writes.  
Accesses to this table must be 32-bit.  
The algorithm for VLAN filtering using the VFTA is identical to that used for the Multicast Table  
Array. Refer to Section 13.5.1 for a block diagram of the algorithm. If VLANs are not used, there is  
no need to initialize the VFTA.  
1. Not applicable to the 82541ER.  
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Register Descriptions  
Table 13-92. VFTA[127:0] Bit Description  
31  
0
VLAN Filter Bit Vector  
Initial  
Value  
Field  
Bit(s)  
Description  
Double-word wide bit vector specifying 32 bits in the VLAN  
Filter table.  
Bit Vector  
31:0  
X
13.6  
Wakeup Registers  
13.6.1  
Wakeup Control Register  
WUC (05800h; R/W)  
This register is reset any time LAN_PWR_GOOD is set to 0b. When AUX_POWER equals 0b,  
this register is also reset by de-asserting (rising edge) RST#.  
31  
4
3
2
1
0
Reserved  
APMPME  
PME_S  
PME_EN  
APME  
Initial  
Value  
Field  
Bit(s)  
Description  
Advance Power Management Enable  
If set to 1b, APM Wakeup is enabled.  
Note: Always 0b for the 82541ER.  
APME  
0
1
0b  
0b  
PME_En  
This read/write bit is used by the driver to access the PME_En  
bit of the Power Management Control / Status Register  
(PMCSR) without writing to the PCI configuration space.  
Note: Do not set this bit for the 82541ER.  
PME_En  
PME_Status  
This bit is set when the Ethernet controller receives a wakeup  
event. It is the same as the PME_Status bit in the Power  
Management Control / Status Register (PMCSR). Writing a 1b  
to this bit clears the PME_Status bit in the PMCSR.  
PME_Status  
2
0b  
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Register Descriptions  
Initial  
Value  
Field  
Bit(s)  
Description  
Assert PME On APM Wakeup  
If set to 1b, the Ethernet controller sets the PME_Status bit in  
the Power Management Control / Status Register (PMCSR)  
and asserts PME# when APM Wakeup is enabled and the  
Ethernet controller receives a matching Magic Packet. This  
field value is loaded from the EEPROM.  
APMPME  
Reserved  
3
0b  
Note: Not applicable to the 82541ER.  
Reserved  
Reads as 0b.  
27:4  
28  
0b  
0b  
Dynamic Powerdown Mode  
When programmed to 1b, enables dynamic powerdown  
operation.  
Dynamic  
Powerdown1  
Automatic Frequency Select  
Determines automatic reduction of MAC frequency in 82541xx  
only. Reserved for the 82547GI/EI.  
Bit 29 controls MAC speed at 1000 MB. When cleared,  
enables the MAC to run at full speed. When set and PCI is  
configured for 33 MHz (82541xx), allows the MAC to run at  
half speed.  
Auto Freq  
Select1  
30:29  
0b2  
Bit 30 controls MAC speed at other Ethernet rates. When  
cleared, allows the MAC to run at full speed. When set, it  
allows the MAC to run at quarter speed.  
If both bits are cleared, the MAC frequency select bits control  
MAC frequency.  
Smart Powerdown MAC  
When programmed to 0b, the MAC operates normally. When  
programmed to 1b, the MAC enters smart powerdown mode.  
SPM1  
31  
0b  
0b  
Reserved  
Reads as 0b.  
Reserved3  
31:28  
1.  
2.  
3.  
82541xx and 82547GI/EI only.  
Loaded from the EEPROM.  
Not applicable to the 82541xx and 82547GI/EI.  
13.6.2  
Wakeup Filter Control Register  
WUFC (05808h; R/W)  
This register is used to enable each of the pre-defined and flexible filters for wakeup support. A  
value of 1b means the filter is turned on, and a value of 0b means the filter is turned off.  
This register is reset any time LAN_PWR_GOOD is 0b. When AUX_POWER equals 0b, this  
register is also reset by deasserting (rising edge) RST#.  
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Register Descriptions  
31  
20  
19  
18  
17  
16  
15  
14  
8
7
6
5
4
3
2
1
0
1
2
3
Reserved  
FLX3 FLX2 FLX1 FLX0 ITCO  
Reserved  
IPv6  
IPv4  
ARP  
BC  
MC  
EX  
MAG LNKC  
1.  
2.  
3.  
82541xx and 82547GI/EI only.  
Not applicable to the 82544GC/EI.  
IP for the 82544GC/EI.  
Field  
Bit(s)  
Initial Value  
0b  
Description  
LNKC  
MAG  
EX  
0
Link Status Change Wakeup Enable.  
Magic Packet Wakeup Enable.  
1
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0
2
Directed Exact Wakeup Enable.  
Directed Multicast Wakeup Enable.  
Broadcast Wakeup Enable.  
MC  
3
BC  
4
ARP  
5
ARP Request Packet Wakeup Enable.  
Directed IPv4 Packet Wakeup Enable.  
Directed IPv6 Packet Wakeup Enable.  
Reserved. Set these bits to 0b.  
IPv41  
IPv62  
Reserved  
ITCO3  
FLX0  
FLX1  
FLX2  
FLX3  
6
7
14:8  
15  
16  
17  
18  
19  
Ignore TCO/management packets for wakeup.  
Flexible Filter 0 Enable.  
0b  
0b  
0b  
0b  
Flexible Filter 1 Enable.  
Flexible Filter 2 Enable.  
Flexible Filter 3 Enable.  
1.  
2.  
3.  
IP for the 82544GC/EI.  
Not applicable to the 82544GC/EI.  
82541xx and 82547GI/EI only.  
13.6.3  
Wakeup Status Register  
WUS (05810h; R)  
This register is used to record statistics about all wakeup packets received. If a packet matches  
multiple criteria then multiple bits could be set. Writing a 1b to any bit clears that bit.  
This register is not cleared when RST# is asserted. It is only cleared when LAN_PWR_GOOD is  
de-asserted or when cleared by the driver software.  
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Register Descriptions  
31  
20  
19  
18  
17  
16  
15  
8
7
6
5
4
3
2
1
0
1
2
Reserved  
FLX3 FLX2 FLX1 FLX0 Reserved  
IPv6  
IPv4  
ARP  
BC  
MC  
EX  
MAG LNKC  
1.  
2.  
Not applicable to the 82544GC/EI.  
IP for the 82544GC/EI.  
Field  
LNKC  
Bit(s)  
Initial Value  
0b  
Description  
0
Link Status Change.  
MAG  
EX  
1
2
0b  
0b  
Magic Packet Received.  
Directed Exact Packet Received  
The packet’s address matched one of the 16 pre-programmed  
exact values in the Receive Address registers.  
Directed Multicast Packet Received  
MC  
3
0b  
The packet was a multicast packet whose hashed to a value  
that corresponded to a 1 bit in the Multicast Table Array.  
BC  
4
0b  
0b  
0b  
0b  
0b  
0b  
0b  
0b  
Broadcast Packet Received.  
ARP Request Packet Received.  
Directed IPv4 Packet Received.  
Directed IPv6 Packet Received.  
Flexible Filter 0 Match.  
ARP  
IPv41  
IPv62  
FLX0  
FLX1  
FLX2  
FLX3  
5
6
7
16  
17  
18  
19  
Flexible Filter 1 Match.  
Flexible Filter 2 Match.  
Flexible Filter 3 Match.  
1.  
2.  
IP for the 82544GC/EI.  
Not applicable to the 82544GC/EI.  
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Register Descriptions  
13.6.4  
IP Address Valid  
IPAV (5838h; R/W)  
The IP Address Valid indicates whether the IP addresses in the IP Address Table are valid.  
The valid bits are reset any time LAN_PWR_GOOD is 0b. When AUX_POWER equals 0b, the  
valid bits are also reset by deasserting (rising edge) RST#.  
31  
17  
16  
15  
4
3
2
1
0
V43  
V32  
V42  
V22  
V41  
V12  
V40  
V02  
Reserved  
v601  
Reserved  
1.  
2.  
Not applicable to the 82544GC/EI.  
82544GC/EI only.  
Field  
V40  
Bit(s)  
Initial Value  
0b1  
Description  
IPv4 Address 0 Valid  
IP Address 0 Valid2  
0
V0  
V41  
V1  
IPv4 Address 1 Valid  
IP Address 1 Valid2  
1
2
0b  
0b  
V42  
V2  
IPv4 Address 2 Valid  
IP Address 2 Valid2  
V43  
V3  
IPv4 Address 3 Valid  
IP Address 3 Valid2  
3
0b  
0b  
V603  
16  
IPv6 Address 0 Valid  
1.  
2.  
3.  
The initial value is loaded from the IP Address Valid bit of the EEPROM’s Management Control Register.  
82544GC/EI only.  
Not applicable to the 82544GC/EI.  
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Register Descriptions  
13.6.5  
IPv4 Address Table1  
2
IP4AT (05840h - 05858h; R/W)  
The IPv4 Address Table is used to store the four IP addresses for ARP Request packet and Directed  
IP packet wakeup for IPv4.  
Note: This table is not cleared by any reset.  
DWORD#  
Address  
5840h  
31  
0
0
IPV4ADDR01  
IPV4ADDR1  
IPV4ADDR2  
IPV4ADDR3  
2
3
4
5848h  
5850h  
5858h  
1.  
IPA for the 82544GC/EI.  
Field  
Dword #  
Address  
Bit(s)  
31:0  
Initial Value  
X2  
Description  
IPv4 Address 0  
IPV4ADDR01  
IPV4ADDR1  
IPV4ADDR2  
IPV4ADDR3  
0
2
4
6
5840h  
5848h  
5850h  
5858h  
31:0  
X
X
X
IPv4 Address 1  
IPv4 Address 2  
IPv4 Address 3  
31:0  
31:0  
1.  
2.  
IPA for the 82544GC/EI.  
The first entry is loaded from the EEPROM if the IP Address Valid field of the EEPROM’s Management Control word is 1b  
and the IP Address Type field is 0b (IPv4). Otherwise, the value of this register is undefined after reset.  
1. IP Address Table for the 82544GC/EI.  
2. IPAT for the 82544GC/EI.  
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Register Descriptions  
13.6.6  
IPv6 Address Table1  
IP6AT (05880h - 0588Ch; R/W)  
The IPv6 Address Table is used to store the IPv6 addresses for ARP Request packet and Directed  
IP packet wakeup for IPv6.  
Note: This table is not cleared by any reset.  
DWORD#  
Address  
5880h  
31  
0
0
1
2
3
5884h  
5888h  
588Ch  
IPV6ADDR0  
Field  
Dword #  
Address  
Bit(s)  
Initial Value1  
Description  
0
1
2
3
5880h  
5884h  
5888h  
588Ch  
31:0  
X
IPv6 Address 0, bytes 1-4  
IPv6 Address 0, bytes 5-8  
IPv6 Address 0, bytes 9-12  
31:0  
31:0  
31:0  
X
X
X
IPV6ADDR0  
IPv6 Address 0, bytes 16-13  
1.  
This table is loaded from the EEPROM if the IP Address Valid field of the EEPROM’s Management Control word is 1b and  
the IP Address Type field is 0b (IPv4). Otherwise, the value of this register is undefined after reset.  
1. Not applicable to the 82544GC/EI.  
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Register Descriptions  
13.6.7  
Wakeup Packet Length  
WUPL (05900h; R/W)  
This register indicates the length of the first wakeup packet received. It is valid if one of the bits in  
the Wakeup Status Register (WUSR) is set. It can be written for diagnostic purposes and is not  
cleared by any reset.  
31  
12  
11  
0
Reserved  
Length  
Field  
Bit(s)  
11:0  
Initial Value  
Description  
Length of wakeup packet. (If jumbo frames is enabled and the  
packet is longer than 2047 bytes this field is 2047.)  
LEN  
X
13.6.8  
Wakeup Packet Memory (128 Bytes)  
WUPM (05A00h - 05A7Ch; R/W)  
This register is read-only and it is used to store the first 128 bytes of the wakeup packet for  
software retrieval after system wakeup. It can be written for diagnostic purposes and is not cleared  
by any reset.  
31  
0
WUPD  
Initial  
Value  
Field  
WUPD  
Bit(s)  
31:0  
Description  
X
Wakeup Packet Data  
13.6.9  
Flexible Filter Length Table  
FFLT (05F00h - 05F18h; R/W)  
The Flexible Filter Length Table stores the minimum packet lengths required to pass each of the  
Flexible Filters. Any packets that are shorter than the programmed length won’t pass that filter.  
Each Flexible Filter considers a packet that doesn’t have any mismatches up to that point to have  
passed the Flexible Filter when it reaches the required length. It does not check any bytes past that  
point.  
All reserved fields read as 0b’s and ignore writes.  
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Register Descriptions  
Before writing to the Flexible Filter Length Table the driver must first disable the flexible filters by  
writing 0b’s to the Flexible Filter Enable bits of the Wakeup Filter Control Register  
(WUFC.FLXn).  
31  
0
31  
11  
10  
0
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Length 0  
Length 1  
Length 2  
Length 3  
Field  
Dword #  
Address  
Bit(s)  
Initial Value  
Description  
LEN0  
LEN1  
LEN2  
LEN3  
0
2
4
6
5F00h  
5F08h  
5F10h  
5F18h  
10:0  
10:0  
10:0  
10:0  
0b  
0b  
0b  
0b  
Minimum Length for Flexible Filter 0  
Minimum Length for Flexible Filter 1  
Minimum Length for Flexible Filter 2  
Minimum Length for Flexible Filter 3  
13.6.10  
Flexible Filter Mask Table  
FFMT (09000h - 093F8h; R/W)  
The Flexible Filter Mask and Table is used to store the four 1-bit masks for each of the first 128  
data bytes in a packet, one for each Flexible Filter. If the mask bit is set to 1b, the corresponding  
Flexible Filter compares the incoming data byte at the index of the mask bit to the data byte stored  
in the Flexible Filter Value Table.  
Before writing to the Flexible Filter Mask Table the driver must first disable the flexible filters by  
writing 0b’s to the Flexible Filter Enable bits of the Wakeup Filter Control Register  
(WUFC.FLXn).  
31  
0
31  
4
3
0
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Byte 0 Mask  
Byte 1 Mask  
Byte 2 Mask  
Byte 126 Mask  
Byte 127 Mask  
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Register Descriptions  
Field  
Dword # Address  
Bit(s)  
15:0  
Initial Value  
Description  
MASK0  
MASK1  
MASK2  
...  
0
2
4
9000h  
9008h  
9010h  
X
Mask for Filter [3:0] for Byte 0  
Mask for Filter [3:0] for Byte 2  
Mask for Filter [3:0] for Byte 3  
15:0  
15:0  
X
X
MASK127 254  
93F8h  
15:0  
X
Mask for Filter [3:0] for Byte 127  
13.6.11 Flexible Filter Value Table  
FFVT (09800h - 09BF8h; R/W)  
The Flexible Filter Value and Table is used to store the one value for each byte location in a packet  
for each flexible filter. If the corresponding mask bit is set to 1b, the Flexible Filter compares the  
incoming data byte to the values stored in this table.  
Before writing to the Flexible Filter Value Table the driver must first disable the flexible filters by  
writing 0b’s to the Flexible Filter Enable bits of the Wakeup Filter Control Register  
(WUFC.FLXn).  
31  
0
31  
24  
23  
16  
15  
Value1  
8
7
0
Reserved  
Reserved  
Reserved  
Reserved  
Byte0: Value3  
Value2  
Value0  
Byte1: Value3  
Byte2: Value3  
Byte127: Value3  
Value2  
Value2  
Value2  
Value1  
Value1  
Value1  
Value0  
Value0  
Value0  
Field  
Dword # Address  
Bit(s)  
15:0  
Initial Value  
Description  
MASK0  
MASK1  
MASK2  
...  
0
2
4
9800h  
9808h  
9810h  
X
X
X
Mask for Filter [3:0] for Byte 0  
Mask for Filter [3:0] for Byte 2  
Mask for Filter [3:0] for Byte 3  
15:0  
15:0  
MASK127 254  
9BF8h  
15:0  
X
Mask for Filter [3:0] for Byte 127  
13.7  
Statistics Registers  
All statistics registers are implemented as 32-bit registers. 64-bit accesses to these registers must  
have the upper byte enables de-asserted. 32-bit registers with addresses not on a quadword  
boundary cannot be accessed through a 64-bit access.  
Registers that count octets make up 64-bit registers.  
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Register Descriptions  
All Statistics registers reset when read. 64-bit registers reset whenever the upper 32 bits are read. In  
addition, they stick at FFFFh_FFFFh when the maximum value is reached.  
The Statistics registers are not hardware initialized. Their default value is unknown. Software  
should read the contents of all registers in order to clear them prior to enabling the receive and  
transmit channels.  
Note: For the receive statistics, it should be noted that a packet is indicated as “received” if it passes the  
device filters, and it is placed in the packet buffer memory. A packet does not have to be transferred  
to host memory in order to be counted as “received.”  
13.7.1  
CRC Error Count  
CRCERRS (04000h; R)  
Counts the number of receive packets with CRC errors. In order for a packet to be counted in this  
register, it must pass address filtering and must be 64 bytes or greater (from <Destination Address>  
through <CRC>, inclusively) in length. If receives are not enabled, then this register does not  
increment.  
Table 13-93. CRCERRS Register Bit Description  
31  
0
CEC  
Initial  
Value  
Field  
Bit(s)  
Description  
CEC  
31:0  
0b  
CRC error count  
13.7.2  
Alignment Error Count  
ALGNERRC (04004h; R)  
Counts the number of receive packets with alignment errors (the packet is not an integer number of  
bytes in length). In order for a packet to be counted in this register, it must pass address filtering  
and must be 64 bytes or greater (from <Destination Address> through <CRC>, inclusively) in  
length. If receives are not enabled, then this register does not increment. This register is valid only  
in MII mode during 10/100 Mb/s operation.  
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Register Descriptions  
Table 13-94. ALGNERRC Register Bit Description  
31  
0
AEC  
Initial  
Value  
Field  
Bit(s)  
Description  
AEC  
31:0  
0b  
Alignment error count  
13.7.3  
Symbol Error Count  
SYMERRS (04008h; R)  
Counts the number of symbol errors between reads. The count increases for every bad symbol  
received, whether or not a packet is currently being received and whether or not the link is up. This  
register only increments in internal SerDes mode (TBI mode for the 82544GC/EI).  
Table 13-95. SYMERRS Register Bit Description  
31  
0
SYMERRS  
Initial  
Value  
Field  
Bit(s)  
Description  
SYMERRS  
31:0  
0b  
Symbol Error Count  
13.7.4  
RX Error Count  
RXERRC (0400Ch; R)  
Counts the number of packets received in which I_RX_ER was asserted by the PHY. In order for a  
packet to be counted in this register, it must pass address filtering and must be 64 bytes or greater  
(from <Destination Address> through <CRC>, inclusively) in length. If receives are not enabled,  
then this register does not increment. In internal SerDes mode (TBI mode for the 82544GC/EI),  
this register increments on the reception of  
/V/ codes.  
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Register Descriptions  
Table 13-96. RXERRC Register Bit Description  
31  
0
RXEC  
Initial  
Value  
Field  
Bit(s)  
Description  
RXEC  
31:0  
0b  
RX error count  
13.7.5  
Missed Packets Count  
MPC (04010h; R)  
Counts the number of missed packets. Packets are missed when the receive FIFO has insufficient  
space to store the incoming packet. This can be caused because of too few buffers allocated, or  
because there is insufficient bandwidth on the PCI bus. Events setting this counter cause RXO, the  
Receiver Overrun Interrupt, to be set. This register does not increment if receives are not enabled.  
These packets are also counted in the Total Packets Received register as well as in Total Octets  
Received.  
Table 13-97. MPC Register Bit Description  
31  
0
MPC  
Initial  
Value  
Field  
Bit(s)  
Description  
MPC  
31:0  
0b  
Missed Packets Count  
13.7.6  
Single Collision Count  
SCC (04014h; R)  
This register counts the number of times that a successfully transmitted packet encountered a single  
collision. This register only increments if transmits are enabled and the Ethernet controller is in  
half-duplex mode.  
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Register Descriptions  
Table 13-98. SCC Register Bit Description  
31  
0
SCC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of times a transmit encountered a single collision.  
SCC  
31:0  
0b  
13.7.7  
Excessive Collisions Count  
ECOL (04018h; R)  
When 16 or more collisions have occurred on a packet, this register increments, regardless of the  
value of collision threshold. If collision threshold is set below 16, this counter won’t increment.  
This register only increments if transmits are enabled and the Ethernet controller is in half-duplex  
mode.  
Table 13-99. ECOL Register Bit Description  
31  
0
ECC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets with more than 16 collisions.  
ECC  
31:0  
0b  
13.7.8  
Multiple Collision Count  
MCC (0401Ch; R)  
This register counts the number of times that a transmit encountered more than one collision but  
less than 16. This register only increments if transmits are enabled and the Ethernet controller is in  
half-duplex mode.  
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Register Descriptions  
Table 13-100. MCC Register Bit Description  
31  
0
MCC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of times a successful transmit encountered multiple  
collisions.  
MCC  
31:0  
0b  
13.7.9  
Late Collisions Count  
LATECOL (04020h; R)  
Late collisions are collisions that occur after 64-byte time into the transmission of the packet while  
working in 10-100 Mb/s data rate, and 512 byte time into the transmission of the packet while  
working in the 1000 Mb/s data rate. This register only increments if transmits are enabled and the  
device is in half-duplex mode.  
Table 13-101. LATECOL Register Bit Description  
31  
0
LCC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets with late collisions.  
LCC  
31:0  
0b  
13.7.10 Collision Count  
COLC (04028h; R)  
This register counts the total number of collisions that are not late collisions seen by the transmitter.  
This register only increments if transmits are enabled and the Ethernet controller is in half-duplex  
mode.  
Table 13-102. COLC Register Bit Description  
31  
0
CCC  
Initial  
Value  
Field  
Bit(s)  
Description  
Total number of collisions experienced by the transmitter.  
CCC  
31:0  
0b  
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Register Descriptions  
13.7.11 Defer Count  
DC (04030h; R)  
This register counts defer events. A defer event occurs when the transmitter cannot immediately  
send a packet due to the medium being busy either because another device is transmitting, the IPG  
timer has not expired, half-duplex deferral events, reception of XOFF frames, or the link is not up.  
This register only increments if transmits are enabled. This counter does not increment for  
streaming transmits that are deferred due to TX IPG.  
Table 13-103. DC Register Bit Description  
31  
0
CDC  
Initial  
Value  
Field  
Bit(s)  
Description  
CDC  
31:0  
0b  
Number of defer events.  
13.7.12 Transmit with No CRS  
TNCRS (04034h; R)  
This register counts the number of successful packet transmissions in which the internal carrier  
sense signal from the PHY was not asserted within one slot time of start of transmission.  
The PHY should assert the internal carrier sense signal during every transmission. Failure to do so  
may indicate that the link has failed, or the PHY has an incorrect link configuration. This register  
1
only increments if transmits are enabled. This register is not valid in internal SerDes mode (TBI  
mode for the 82544GC/EI), and is only valid when the Ethernet controller is operating at full  
duplex.  
Table 13-104. TNCRS Register Bit Description  
31  
0
TNCRS  
Initial  
Value  
Field  
TNCRS  
Bit(s)  
Description  
Number of transmissions without a CRS assertion from the PHY.  
31:0  
0b  
1. The 82540EP/EM, 82541xx, and 82547GI/EI do not support SerDes functionality.  
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Register Descriptions  
13.7.13 Sequence Error Count  
SEC (04038h; R)  
This register counts sequence error events. The proper sequence of 8b/10b symbols is as follows:  
idle, start-of-frame (SOF), data, pad (optional), end-of-frame (EOF), fill (optional), idle. Hardware  
increments this counter for any illegal sequence of delimiters. If the link is not up, this register does  
not increment. This register is only valid in internal SerDes mode (TBI mode for the 82544GC/  
EI).  
Table 13-105. SEC Register Bit Description  
31  
0
SEC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of sequence error events.  
SEC  
31:0  
0b  
13.7.14 Carrier Extension Error Count  
CEXTERR (0403Ch; R)  
This register counts the number of packets received in which the carrier extension error was  
signaled across the internal PHY interface. The PHY propagates carrier extension errors to the  
MAC when an error is detected during the carrier extended time of a packet reception. An  
extension error is signaled by the PHY by the encoding of 1Fh on the receive data inputs. This  
register only increments if receives are enabled and the Ethernet controller is operating at  
1000 Mb/s. For example, internal PHY or internal SerDes modes (internal PHY or TBI modes for  
the 82544GC/EI).  
Table 13-106. CEXTERR Register Bit Description  
31  
0
CEXTERR  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets received with a carrier extension error.  
CEXTERR  
31:0  
0b  
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Register Descriptions  
13.7.15 Receive Length Error Count  
RLEC (04040h; R)  
This register counts receive length error events. A length error occurs if an incoming packet passes  
the filter criteria but is undersized or oversized. Packets less than 64 bytes are undersized. Packets  
over 1522 bytes are oversized if LongPacketEnable is 0b (RCTL.LPE). If LongPacketEnable  
(LPE) is 1b, then an incoming packet is considered oversized if it exceeds 16384 bytes.  
If receives are not enabled, this register does not increment. These lengths are based on bytes in  
the received packet from <Destination Address> through <CRC>, inclusively.  
Table 13-107. RLEC Register Bit Description  
31  
0
RLEC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets with receive length errors.  
RLEC  
31:0  
0b  
13.7.16 XON Received Count  
XONRXC (04048h; R)  
This register counts the number of valid XON packets received. XON packets can use the global  
address, or the station address. This register only increments if receives are enabled.  
Table 13-108. XONRXC Register Bit Description  
31  
0
XONRXC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of XON packets received.  
XONRXC  
31:0  
0b  
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Register Descriptions  
13.7.17 XON Transmitted Count  
XONTXC (0404Ch; R)  
This register counts the number of XON packets transmitted. These can be either due to a full  
queue or due to software initiated action (using TCTL.SWXOFF). This register only increments if  
transmits are enabled.  
Table 13-109. XONTXC Register Bit Description  
31  
0
XONTXC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of XON packets transmitted.  
XONTXC  
31:0  
0b  
13.7.18 XOFF Received Count  
XOFFRXC (04050h; R)  
This register counts the number of valid XOFF packets received. XOFF packets can use the global  
address or the station address. This register only increments if receives are enabled.  
Table 13-110. XOFFRXC Register Bit Description  
31  
0
XOFFRXC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of XOFF packets received.  
XOFFRXC  
31:0  
0b  
13.7.19 XOFF Transmitted Count  
XOFFTXC (04054h; R)  
This register counts the number of XOFF packets transmitted. These can be either due to a full  
queue or due to software initiated action (using TCTL.SWXOFF). This register only increments if  
transmits are enabled.  
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Register Descriptions  
Table 13-111. XOFFTXC Register Bit Description  
31  
0
XOFFTXC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of XOFF packets transmitted.  
XOFFTXC  
31:0  
0b  
13.7.20 FC Received Unsupported Count  
FCRUC (04058h; R)  
This register counts the number of unsupported flow control frames that are received.  
The FCRUC counter increments when a flow control packet is received that matches either the  
reserved flow control multicast address (in FCAH/L) or the MAC station address, and has a  
matching flow control type field match (to the value in FCT), but has an incorrect opcode field.  
This register only increments if receives are enabled.  
Table 13-112. FCRUC Register Bit Description  
31  
0
FCRUC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of unsupported flow control frames received.  
FCRUC  
31:0  
0b  
13.7.21 Packets Received (64 Bytes) Count  
PRC64 (0405Ch; R)  
This register counts the number of good packets received that are exactly 64 bytes (from  
<Destination Address> through <CRC>, inclusively) in length. Packets that are counted in the  
Missed Packet Count register are not counted in this register. This register does not include  
received flow control packets and increments only if receives are enabled.  
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Register Descriptions  
Table 13-113. PRC64 Register Bit Description  
31  
0
PRC64  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets received that are 64 bytes in length.  
PRC64  
31:0  
0b  
13.7.22 Packets Received (65-127 Bytes) Count  
PRC127 (04060h; R)  
This register counts the number of good packets received that are 65-127 bytes (from <Destination  
Address> through <CRC>, inclusively) in length. Packets that are counted in the Missed Packet  
Count register are not counted in this register. This register does not include received flow control  
packets and increments only if receives are enabled.  
Table 13-114. PRC127 Register Bit Description  
31  
0
PRC127  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets received that are 65-127 bytes in length.  
PRC127  
31:0  
0b  
13.7.23 Packets Received (128-255 Bytes) Count  
PRC255 (04064h; R)  
This register counts the number of good packets received that are 128-255 bytes (from  
<Destination Address> through <CRC>, inclusively) in length. Packets that are counted in the  
Missed Packet Count register are not counted in this register. This register does not include  
received flow control packets and increments only if receives are enabled.  
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Register Descriptions  
Table 13-115. PRC225 Register Bit Description  
31  
0
PRC255  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets received that are 128-255 bytes in length.  
PRC255  
31:0  
0b  
13.7.24 Packets Received (256-511 Bytes) Count  
PRC511 (04068h; R)  
This register counts the number of good packets received that are 256-511 bytes (from  
<Destination Address> through <CRC>, inclusively) in length. Packets that are counted in the  
Missed Packet Count register are not counted in this register. This register does not include  
received flow control packets and increments only if receives are enabled.  
Table 13-116. PRC551 Register Bit Description  
31  
0
PRC511  
Initial  
Value  
Field  
Bit(s)  
Description  
PRC511  
31:0  
0b  
Number of packets received that are 256-511 bytes in length.  
13.7.25 Packets Received (512-1023 Bytes) Count  
PRC1023 (0406Ch; R)  
This register counts the number of good packets received that are 512-1023 bytes (from  
<Destination Address> through <CRC>, inclusively) in length. Packets that are counted in the  
Missed Packet Count register are not counted in this register. This register does not include  
received flow control packets and increments only if receives are enabled.  
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Register Descriptions  
Table 13-117. PRC1023 Register Bit Description  
31  
0
PRC1023  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets received that are 512-1023 bytes in length.  
PRC1023  
31:0  
0b  
13.7.26 Packets Received (1024 to Max Bytes) Count  
PRC1522 (04070h; R)  
This register counts the number of good packets received that are from 1024 bytes to the maximum  
(from <Destination Address> through <CRC>, inclusively) in length. The maximum is dependent  
on the current receiver configuration and the type of packet being received. If a packet is counted in  
Receive Oversized Count, it is not counted in this register (see Section 13.7.36). This register does  
not include received flow control packets and only increments if the packet has passed address  
filtering and receives are enabled.  
Due to changes in the standard for maximum frame size for VLAN tagged frames in IEEE  
Standard 802.3, these Ethernet controllers accept packets which have a maximum length of 1522  
bytes. The RMON statistics associated with this range has been extended to count 1522-byte long  
packets.  
Table 13-118. PRC1522 Register Bit Description  
31  
0
PRC1522  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets received that are 1024-Max bytes in length.  
PRC1522  
31:0  
0b  
13.7.27 Good Packets Received Count  
GPRC (04074h; R)  
This register counts the number of good packets received of any legal length. The legal length for  
the received packet is defined by the value of LongPacketEnable (CTRL.LPE) (see Section  
13.7.15). This register does not include received flow control packets and only counts packets that  
pass filtering. This register only increments if receives are enabled. This register does not count  
packets counted by the Missed Packet Count (MPC) register.  
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Register Descriptions  
Table 13-119. GPRC Register Bit Description  
31  
0
GPRC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of good packets received (of any length).  
GPRC  
31:0  
0b  
13.7.28 Broadcast Packets Received Count  
BPRC (04078h; R)  
This register counts the number of good (no errors) broadcast packets received. This register does  
not count broadcast packets received when the broadcast address filter is disabled. This register  
only increments if receives are enabled.  
Table 13-120. BPRC Register Bit Description  
31  
0
BPRC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of broadcast packets received.  
BPRC  
31:0  
0b  
13.7.29 Multicast Packets Received Count  
MPRC (0407Ch; R)  
This register counts the number of good (no errors) multicast packets received. This register does  
not count multicast packets received that fail to pass address filtering nor does it count received  
flow control packets. This register only increments if receives are enabled. This register does not  
count packets counted by the Missed Packet Count (MPC) register.  
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Register Descriptions  
Table 13-121. MPRC Register Bit Description  
31  
0
MPRC  
Initial  
Value  
Field  
Bit(s)  
Description  
MPRC  
31:0  
0b  
Number of multicast packets received.  
13.7.30 Good Packets Transmitted Count  
GPTC (04080h; R)  
This register counts the number of good (no errors) packets transmitted. A good transmit packet is  
considered one that is 64 or more bytes in length (from <Destination Address> through <CRC>,  
inclusively) in length. This does not include transmitted flow control packets. This register only  
increments if transmits are enabled.  
Table 13-122. GPTC Register Bit Description  
31  
0
GPTC  
Initial  
Value  
Field  
GPTC  
Bit(s)  
31:0  
Description  
Number of good packets transmitted.  
0b  
13.7.31 Good Octets Received Count  
GORCL (04088h; R)/GORCH (0408Ch; R)  
These registers make up a 64-bit register that counts the number of good (no errors) octets  
received. This register includes bytes received in a packet from the <Destination Address> field  
through the <CRC> field, inclusively. This register resets each time the upper 32 bits are read  
(GORCH).  
In addition, it sticks at FFFFh_FFFFh_FFFFh_FFFFh when the maximum value is reached. Only  
octets of packets that pass address filtering are counted in this register. This register only  
increments if receives are enabled.  
These octets do not include octets of received flow control packets.  
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Register Descriptions  
Table 13-123. GORCL and GORCH Register Bit Description  
31  
0
31  
0
GORCH  
GORCL  
Initial  
Value  
Field  
Bit(s)  
Description  
GORCL  
GORCH  
31:0  
31:0  
0b  
0b  
Number of good octets received – lower 4 bytes.  
Number of good octets received – upper 4 bytes.  
13.7.32 Good Octets Transmitted Count  
GOTCL (04090h; R)/ GOTCH (04094; R)  
These registers make up a 64-bit register that counts the number of good (no errors) octets  
transmitted. This register resets each time the upper 32 bits are read (GOTCH).  
In addition, it sticks at FFFF_FFFF_FFFF_FFFFh when the maximum value is reached. This  
register includes bytes transmitted in a packet from the <Destination Address> field through the  
<CRC> field, inclusively. This register counts octets in successfully transmitted packets that are 64  
or more bytes in length. This register only increments if transmits are enabled.  
These octets do not include octets in transmitted flow control packets.  
Table 13-124. GOTCL and GOTCH Register Bit Description  
31  
0
31  
0
GOTCH  
GOTCL  
Initial  
Value  
Field  
Bit(s)  
Description  
GOTCL  
GOTCH  
31:0  
31:0  
0b  
0b  
Number of good octets transmitted – lower 4 bytes.  
Number of good octets transmitted – upper 4 bytes.  
13.7.33 Receive No Buffers Count  
RNBC (040A0h; R)  
This register counts the number of times that frames were received when there were no available  
buffers in host memory to store those frames (receive descriptor head and tail pointers were equal).  
The packet is still received if there is space in the FIFO. This register only increments if receives  
are enabled.  
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Register Descriptions  
This register does not increment when flow control packets are received.  
Table 13-125. RNBC Register Bit Description  
31  
0
RNBC  
Initial  
Value  
Field  
RNBC  
Bit(s)  
31:0  
Description  
0b  
Number of receive no buffer conditions.  
13.7.34 Receive Undersize Count  
RUC (040A4h; R)  
This register counts the number of received frames that passed address filtering, and were less than  
minimum size (64 bytes from <Destination Address> through <CRC>, inclusively), and had a  
valid CRC. This register only increments if receives are enabled.  
Table 13-126. RUC Register Bit Description  
31  
0
RUC  
Initial  
Value  
Field  
Bit(s)  
31:0  
Description  
Number of receive undersize errors.  
RUC  
0b  
13.7.35 Receive Fragment Count  
RFC (040A8h; R)  
This register counts the number of received frames that passed address filtering, and were less than  
minimum size (64 bytes from <Destination Address> through <CRC>, inclusively), but had a bad  
CRC (this is slightly different from the Receive Undersize Count register). This register only  
increments if receives are enabled.  
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Register Descriptions  
Table 13-127. RFC Register Bit Description  
31  
0
RFC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of receive fragment errors.  
RFC  
31:0  
0b  
13.7.36 Receive Oversize Count  
ROC (040ACh; R)  
This register counts the number of received frames with valid CRC field that passed address  
filtering, and were greater than maximum size. Packets over 1522 bytes are oversized if LongPack-  
etEnable (RCTL.LPE) is 0b. If LongPacketEnable is 1b, then an incoming packet is considered  
oversized if it exceeds 16384 bytes.  
If receives are not enabled, this register does not increment. These lengths are based on bytes in the  
received packet from <Destination Address> through <CRC>, inclusively.  
Table 13-128. ROC Register Bit Description  
31  
0
ROC  
Initial  
Value  
Field  
Bit(s)  
31:0  
Description  
Number of receive oversize errors.  
ROC  
0b  
13.7.37 Receive Jabber Count  
RJC (040B0h; R)  
This register counts the number of received frames that passed address filtering, and were greater  
than maximum size and had a bad CRC (this is slightly different from the Receive Oversize Count  
register).  
Packets over 1522 bytes are oversized if LongPacketEnable (RCTL.LPE) is 0b.  
If LongPacketEnable is 1b, then an incoming packet is considered oversized if it exceeds 16384  
bytes.  
If receives are not enabled, this register does not increment. These lengths are based on bytes in the  
received packet from <Destination Address> through <CRC>, inclusively.  
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Table 13-129. RJC Register Bit Description  
31  
0
RJC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of receive jabber errors.  
RJC  
31:0  
0b  
13.7.38 Management Packets Received Count1  
MGTPRC (040B4h; R)  
This register counts the total number of packets received that pass the management filters as  
described in the appropriate Total Cost of Ownership (TCO) System Management Bus Interface  
Application Notes. Management packets include RMCP and ARP packets. Any packets with errors  
are not counted, except that packets dropped because the management receive FIFO is full or the  
packet is longer than 200 bytes is counted.  
31  
0
MGTPRC  
Initial  
Value  
Field  
Bit(s)  
31:0  
Description  
Number of management packets received.  
MGTPRC  
0b  
1. Not applicable to the 82544GC/EI or 82541ER.  
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Register Descriptions  
13.7.39 Management Packets Dropped Count1  
MGTPDC (040B8h; R)  
This register counts the total number of packets received that pass the management filters as  
described in the appropriate Total Cost of Ownership (TCO) System Management Bus Interface  
Application Notes and then are dropped because the management receive FIFO is full or the packet  
is longer than 200 bytes. Management packets include RMCP and ARP packets.  
31  
0
MGTPDC  
Initial  
Value  
Field  
Bit(s)  
31:0  
Description  
Number of management packets dropped.  
MGTPDC  
0b  
13.7.40 Management Pkts Transmitted Count1  
MGTPTC (040BCh; R)  
This register counts the total number of packets that are transmitted that are either received over the  
SMBus or are generated by the Ethernet controller’s ASF function.  
31  
0
MGTPTC  
Initial  
Value  
Field  
Bit(s)  
31:0  
Description  
Number of management packets transmitted.  
MGTPTC  
0b  
13.7.41 Total Octets Received  
TORL (040C0h; R) / TORH (040C4h; R)  
These registers make up a 64-bit register that counts the total number of octets received. This  
register resets each time the upper 32 bits are read (TORH). In addition, it sticks at  
FFFF_FFFF_FFFF_FFFFh when the maximum value is reached.  
1. Not applicable to the 82544GC/EI or 82541ER.  
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All packets received have their octets summed into this register, regardless of their length, whether  
they are erred, or whether they are flow control packets. This register includes bytes received in a  
packet from the <Destination Address> field through the <CRC> field, inclusively. This register  
only increments if receives are enabled.  
Table 13-130. TORL and TORH Register Bit Descriptions  
31  
0
31  
0
TORH  
TORL  
Initial  
Value  
Field  
Bit(s)  
Description  
TORL  
TORH  
31:0  
31:0  
0b  
0b  
Number of total octets received – lower 4 bytes.  
Number of total octets received – upper 4 bytes.  
13.7.42 Total Octets Transmitted  
TOTL (040C8h; R/W / TOTH (040CCh; R)  
These registers make up a 64-bit register that counts the total number of octets transmitted. This  
register resets each time the upper 32 bits are read (TOTH). In addition, it sticks at  
FFFF_FFFF_FFFF_FFFFh when the maximum value is reached.  
All transmitted packets have their octets summed into this register, regardless of their length or  
whether they are flow control packets. This register includes bytes transmitted in a packet from the  
<Destination Address> field through the <CRC> field, inclusively.  
Octets transmitted as part of partial packet transmissions (collisions in half-duplex mode) are not  
included in this register. This register only increments if transmits are enabled.  
Table 13-131. TOTL and TOTH Register Bit Descriptions  
31  
0
31  
0
TOTH  
TOTL  
Initial  
Value  
Field  
Bit(s)  
Description  
TOTL  
TOTH  
31:0  
31:0  
0b  
0b  
Number of total octets transmitted – lower 4 bytes.  
Number of total octets transmitted – upper 4 bytes.  
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Register Descriptions  
13.7.43 Total Packets Received  
TPR (040D0h; R)  
This register counts the total number of all packets received. All packets received are counted in  
this register, regardless of their length, whether they have errors, or whether they are flow control  
packets. This register only increments if receives are enabled.  
Table 13-132. TPR Register Bit Description  
31  
0
TPR  
Initial  
Value  
Field  
Bit(s)  
31:0  
Description  
Number of all packets received.  
TPR  
0b  
13.7.44 Total Packets Transmitted  
TPT (040D4h; R)  
This register counts the total number of all packets transmitted. All packets transmitted are counted  
in this register, regardless of their length, or whether they are flow control packets.  
Partial packet transmissions (collisions in half-duplex mode) are not included in this register. This  
register only increments if transmits are enabled. This register counts all packets, including  
1
standard packets, secure packets, packets received over the SMBus , and packets generated by the  
ASF function.  
Table 13-133. TPT Register Bit Description  
31  
0
TPT  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of all packets transmitted.  
TPT  
31:0  
0b  
1. The 82544GC/EI and the 82541ER do not support SMBus or ASF functionality.  
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13.7.45 Packets Transmitted (64 Bytes) Count  
PTC64 (040D8h; R)  
This register counts the number of packets transmitted that are exactly 64 bytes (from <Destination  
Address> through <CRC>, inclusively) in length. Partial packet transmissions (collisions in half-  
duplex mode) are not included in this register. This register does not include transmitted flow  
control packets (which are 64 bytes in length). This register only increments if transmits are  
enabled. This register counts all packets, including standard packets, secure packets, packets  
received over the SMBus, and packets generated by the ASF function.  
Table 13-134. PTC64 Register Bit Description  
31  
0
PTC64  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets transmitted that are 64 bytes in length.  
PTC64  
31:0  
0b  
13.7.46 Packets Transmitted (65-127 Bytes) Count  
PTC127 (040DCh; R)  
This register counts the number of packets transmitted that are 65-127 bytes (from <Destination  
Address> through <CRC>, inclusively) in length. Partial packet transmissions (collisions in half-  
duplex mode) are not included in this register. This register only increments if transmits are  
enabled. This register counts all packets, including standard packets, secure packets, packets  
1
received over the SMBus , and packets generated by the ASF function.  
Table 13-135. PTC127 Register Bit Description  
31  
0
PTC127  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets transmitted that are 65-127 bytes in length.  
PTC127  
31:0  
0b  
1. The 82544GC/EI does not support SMBus or ASF functionality.  
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13.7.47 Packets Transmitted (128-255 Bytes) Count  
PTC255 (040E0h; R)  
This register counts the number of packets transmitted that are 128-255 bytes (from <Destination  
Address> through <CRC>, inclusively) in length. Partial packet transmissions (collisions in half-  
duplex mode) are not included in this register. This register only increments if transmits are  
enabled. This register counts all packets, including standard packets, secure packets, packets  
received over the SMBus, and packets generated by the ASF function.  
Table 13-136. PTC255 Register Bit Description  
31  
0
PTC255  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets transmitted that are 128-255 bytes in  
length.  
PTC255  
31:0  
0b  
13.7.48 Packets Transmitted (256-511 Bytes) Count  
PTC511 (040E4h; R)  
This register counts the number of packets transmitted that are 256-511 bytes (from <Destination  
Address> through <CRC>, inclusively) in length. Partial packet transmissions (collisions in half-  
duplex mode) are not included in this register. This register only increments if transmits are  
enabled. This register counts all packets, including standard packets, secure packets, packets  
1
received over the SMBus , and packets generated by the ASF function.  
Table 13-137. PTC511 Register Bit Description  
31  
0
PTC511  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets transmitted that are 256-511 bytes in  
length.  
PTC511  
31:0  
0b  
1. The 82544GC/EI does not support SMBus or ASF functionality.  
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13.7.49 Packets Transmitted (512-1023 Bytes) Count  
PTC1023 (040E8h; R)  
This register counts the number of packets transmitted that are 512-1023 bytes (from <Destination  
Address> through <CRC>, inclusively) in length. Partial packet transmissions (collisions in half-  
duplex mode) are not included in this register. This register only increments if transmits are  
enabled.This register counts all packets, including standard packets, secure packets, packets  
received over the SMBus, and packets generated by the ASF function.  
Table 13-138. PTC1023 Register Bit Description)  
31  
0
PTC1023  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets transmitted that are 512-1023 bytes in length.  
PTC1023  
31:0  
0b  
13.7.50 Packets Transmitted (1024 Bytes or Greater) Count  
PTC1522 (040ECh; R)  
This register counts the number of packets transmitted that are 1024 or more bytes (from  
<Destination Address> through <CRC>, inclusively) in length. Partial packet transmissions  
(collisions in half-duplex mode) are not included in this register. This register only increments if  
transmits are enabled.  
Due to the maximum frame size for VLAN tagged frames in IEEE Standard 802.3ac, these  
Ethernet controllers transmit packets that have a maximum length of 1522 bytes. The RMON  
statistics associated with this range has been extended to count 1522 byte long packets. This  
register counts all packets, including standard packets, secure packets, packets received over the  
1
SMBus , and packets generated by the ASF function.  
Table 13-139. PTC1522 Register Bit Description  
31  
0
PTC1522  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of packets transmitted that are 1024 or more bytes in  
length.  
PTC1522  
31:0  
0b  
1. The 82544GC/EI does not support SMBus or ASF functionality.  
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13.7.51 Multicast Packets Transmitted Count  
MPTC (040F0h; R)  
This register counts the number of multicast packets transmitted. This register does not include  
flow control packets and increments only if transmits are enabled. Counts clear as well as secure  
traffic.  
Table 13-140. MPTC Register Bit Description  
31  
0
MPTC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of multicast packets transmitted.  
MPTC  
31:0  
0b  
13.7.52 Broadcast Packets Transmitted Count  
BPTC (040F4h; R)  
This register counts the number of broadcast packets transmitted. This register only increments if  
transmits are enabled.Counts clear as well as secure traffic. (Management packets are never more  
than 200 bytes).  
Table 13-141. BPTC Register Bit Description  
31  
0
BPTC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of broadcast packets transmitted count.  
BPTC  
31:0  
0b  
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13.7.53 TCP Segmentation Context Transmitted Count  
TSCTC (040F8h; R)  
This register counts the number of TCP segmentation offload transmissions and increments once  
the last portion of the TCP segmentation context payload is segmented and loaded as a packet into  
the Ethernet controller’s on-chip transmit buffer. Note that this is not a measurement of the number  
of packets sent out (covered by other registers). This register only increments if transmits and TCP  
Segmentation offload are enabled.  
31  
0
TSCTC  
Initial  
Value  
Field  
Bit(s)  
31:0  
Description  
Number of TCP Segmentation contexts transmitted count.  
TSCTC  
0b  
13.7.54 TCP Segmentation Context Transmit Fail Count  
TSCTFC (040FCh; R)  
This register counts the number of TCP segmentation offload requests to the hardware that failed to  
transmit all data in the TCP segmentation context payload. There is no indication by hardware of  
how much data was successfully transmitted. Only one failure event is logged per TCP  
segmentation context. Failures can be caused by excessive collisions or PAYLEN errors. This  
register only increments if transmits are enabled.  
31  
0
TSCTFC  
Initial  
Value  
Field  
Bit(s)  
Description  
Number of TCP Segmentation contexts where the Ethernet  
controller failed to transmit the entire data payload.  
TSCTFC  
31:0  
0b  
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13.8  
Diagnostics Registers  
The Ethernet controller contains several diagnostic registers. These registers enable software to  
directly access the contents of the Ethernet controller’s internal Packet Buffer Memory (PBM), also  
referred to as FIFO space. These registers also give software visibility into what locations in the  
PBM that the hardware currently considers to be the “head” and “tail” for both transmit and receive  
operations.  
13.8.1  
Receive Data FIFO Head Register  
RDFH (02410h; R/W)  
This register stores the head of the Ethernet controller’s on–chip receive data FIFO. Since the  
internal FIFO is organized in units of 64-bit words, this field contains the 64-bit offset of the  
current Receive FIFO Head. So a value of “8h” in this register corresponds to an offset of 8  
quadwords into the Receive FIFO space. This register is available for diagnostic purposes only, and  
should not be written during normal operation.  
Table 13-142. RDFH Register Bit Description  
31  
13 12  
0
Reserved  
FIFO Head  
Initial  
Value  
Field  
Bit(s)  
Description  
Receive FIFO Head pointer.  
Reads as 0b. Should be written to 0b for future compatibility.  
FIFO Head  
Reserved  
12:0  
0b  
0b  
31:13  
13.8.2  
Receive Data FIFO Tail Register  
RDFT (02418h; R/W)  
This register stores the tail of the Ethernet controller’s on–chip receive data FIFO. Since the  
internal FIFO is organized in units of 64-bit words, this field contains the 64-bit offset of the  
current Receive FIFO Tail. So a value of “8h” in this register corresponds to an offset of eight  
quadwords or into the Receive FIFO space. This register is available for diagnostic purposes only,  
and should not be written during normal operation.  
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Register Descriptions  
Table 13-143. RDFT Register Bit Description  
31  
13 12  
0
Reserved  
FIFO Tail  
Initial  
Value  
Field  
Bit(s)  
Description  
FIFO Tail  
Reserved  
12:0  
0b  
0b  
Receive FIFO Tail pointer.  
31:13  
Reads as 0b. Should be written to 0b for future compatibility.  
13.8.3  
Receive Data FIFO Head Saved Register  
RDFHS (02420h; R/W)  
This register stores a copy of the Receive Data FIFO Head register in case the internal register  
needs to be restored. This register is available for diagnostic purposes only, and should not be  
written during normal operation.  
Table 13-144. RDFHS Register Bit Description  
31  
13 12  
0
Reserved  
FIFO Head  
Initial  
Value  
Field  
Bit(s)  
Description  
FIFO Head  
Reserved  
12:0  
0b  
0b  
A “saved” value of the Receive FIFO Head pointer.  
31:13  
Reads as 0b. Should be written to 0b for future compatibility.  
13.8.4  
Receive Data FIFO Tail Saved Register  
RDFTS (02428h; R/W)  
This register stores a copy of the Receive Data FIFO Tail register in case the internal register needs  
to be restored. This register is available for diagnostic purposes only, and should not be written  
during normal operation.  
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Register Descriptions  
Table 13-145. RDFTS Register Bit Description  
31  
13 12  
0
Reserved  
FIFO Tail  
Initial  
Value  
Field  
Bit(s)  
Description  
FIFO Tail  
Reserved  
12:0  
0b  
0b  
A “saved” value of the Receive FIFO Tail pointer.  
31:13  
Reads as 0b. Should be written to 0b for future compatibility.  
13.8.5  
Receive Data FIFO Packet Count  
RDFPC (02430h; R/W)  
This register reflects the number of receive packets that are currently in the Receive FIFO. This  
register is available for diagnostic purposes only, and should not be written during normal  
operation.  
Table 13-146. RDFPC Register Bit Description  
31  
13 12  
0
Reserved  
FIFO Tail  
Initial  
Value  
Field  
Bit(s)  
Description  
RX FIFO  
Packet Count  
12:0  
0b  
0b  
The number of received packets currently in the RX FIFO.  
Reads as 0b. Should be written to 0b for future compatibility.  
Reserved  
31:13  
13.8.6  
Transmit Data FIFO Head Register  
TDFH (03410h; R/W)  
This register stores the head of the Ethernet controller’s on–chip transmit data FIFO. Since the  
internal FIFO is organized in units of 64-bit words, this field contains the 64-bit offset of the  
current Transmit FIFO Head. So a value of “8h” in this register corresponds to an offset of 8  
quadwords into the Transmit FIFO space. This register is available for diagnostic purposes only,  
and should not be written during normal operation.  
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Register Descriptions  
Table 13-147. TDFH Register Bit Description)  
31  
11 10  
0
Reserved  
FIFO Head  
Initial  
Value  
Field  
Bit(s)  
Description  
Transmit FIFO Head pointer.  
Reads as 0b. Should be written to 0b for future compatibility.  
FIFO Head  
Reserved  
10:0  
0b  
31:11  
0b  
13.8.7  
Transmit Data FIFO Tail Register  
TDFT (03418h; R/W)  
This register stores the head of the Ethernet controller’s on–chip transmit data FIFO. Since the  
internal FIFO is organized in units of 64-bit words, this field contains the 64-bit offset of the  
current Transmit FIFO Tail. So a value of “8h” in this register corresponds to an offset of 8  
quadwords into the Transmit FIFO space. This register is available for diagnostic purposes only,  
and should not be written during normal operation.  
Table 13-148. TDFT Register Bit Description  
31  
11 10  
0
Reserved  
FIFO Tail  
Initial  
Value  
Field  
Bit(s)  
Description  
Transmit FIFO tail pointer.  
Reads as 0b. Should be written to 0b for future compatibility.  
FIFO Tail  
Reserved  
10:0  
0b  
31:11  
0b  
13.8.8  
Transmit Data FIFO Head Saved Register  
TDFHS (03420h; R/W)  
This register stores a copy of the Transmit Data FIFO Head register in case the internal register  
needs to be restored. This register is available for diagnostic purposes only, and should not be  
written during normal operation.  
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Table 13-149. TDFHS Register Bit Description  
31  
13 12  
0
Reserved  
FIFO Head  
Initial  
Value  
Field  
Bit(s)  
Description  
FIFO Head  
Reserved  
12:0  
0b  
A “saved” value of the Transmit FIFO Head pointer.  
31:13  
0b  
Reads as 0b. Should be written to 0b for future compatibility.  
13.8.9  
Transmit Data FIFO Tail Saved Register  
TDFTS (03428h; R/W)  
This register stores a copy of the Transmit Data FIFO Tail register in case the internal register  
needs to be restored. This register is available for diagnostic purposes only, and should not be  
written during normal operation.  
Table 13-150. TDFTS Register Bit Description  
31  
13 12  
0
Reserved  
FIFO Tail  
Initial  
Value  
Field  
Bit(s)  
Description  
FIFO Tail  
Reserved  
12:0  
0b  
A “saved” value of the Transmit FIFO Tail pointer.  
31:13  
0b  
Reads as 0b. Should be written to 0b for future compatibility.  
13.8.10 Transmit Data FIFO Packet Count  
TDFPC (03430h; R/W)  
This register reflects the number of packets to be transmitted that are currently in the Transmit  
FIFO. This register is available for diagnostic purposes only, and should not be written during  
normal operation.  
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Table 13-151. TDFPC Register Bit Description  
31  
13 12  
0
Reserved  
FIFO Tail  
Initial  
Value  
Field  
Bit(s)  
Description  
The number of packets to be transmitted that are currently in  
the TX FIFO.  
FIFO Tail  
Reserved  
12:0  
0b  
31:13  
0b  
Reads as 0b. Should be written to 0b for future compatibility.  
13.8.11 Packet Buffer Memory  
PBM (10000h - 1FFFCh; R/W)  
All PBM (FIFO) data is available to diagnostics. Locations can be accessed as 32-bit or 64-bit  
words. The internal PBM is 64 KB (40 KB for the 82547GI/EI) in size. Software can configure the  
amount of PBM space that is used as the transmit FIFO versus the receive FIFO. The default is 16  
KB of transmit FIFO space and 48 KB of receive FIFO space. For the 82547GI/EI, the default is  
18 KB of transmit FIFO space and 22 KB of receive FIFO space.  
Regardless of the individual FIFO sizes that software configures, the RX FIFO is located first in  
the memory mapped PBM space. So for the default FIFO configuration, the RX FIFO occupies  
offsets 10000h - 1BFFFh of the memory mapped space, while the TX FIFO occupies offsets  
1C000h - 1FFFFh of the memory mapped space.  
Table 13-152. PBM Bit Description  
31  
0
FIFO Data  
Initial  
Value  
Field  
Bit(s)  
Description  
FIFO Data  
31:0  
0b  
Packet Buffer Data  
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General Initialization and Reset  
Operation  
14  
14.1  
14.2  
14.3  
Introduction  
This section lists all necessary initializations and describes the reset commands for the PCI/PCI-X  
Family of Gigabit Ethernet Controllers.  
Note: TBI mode is used by the 82544GC/EI. Internal SerDes is used by the 82546GB/EB and  
82545GM/EM.  
Power Up State  
At power up, the Ethernet controller is not automatically configured by the hardware for normal  
operation. Software initialization is required before normal operation can continue. In general, the  
Ethernet controller is considered non-functional until the software driver successfully loads and  
sets up the hardware. However, Auto-Negotiation can start at power up or upon receipt of an  
assertion of PCI reset if configured to do so by the EEPROM.  
General Configuration  
Several values in the Device Control Register (CTRL) need to be set upon power up or after an  
Ethernet controller reset for normal operation.  
• Speed and duplex are determined via Auto-Negotiation by the PHY, Auto-Negotiation by the  
1
MAC for internal SerDes mode, or forced by software if the link is forced. In internal PHY  
mode, the Ethernet controller can be configured automatically by hardware or forced by  
software to the same configuration as the PHY.  
• In internal PHY mode, the Auto-Speed Detection Enable (CTRL.ASDE) bit, when set to 1b,  
detects the resolved speed and duplex of the link and self-configure the MAC appropriately.  
This bit should be set in conjunction with the Set Link Up (CTRL.SLU) bit.  
• The MAC can also be forced to a specific Speed/Duplex combination. This is accomplished by  
setting the Set Link Up (CTRL.SLU), Force Speed (CTRL. FRCSPD) and Force Duplex  
(CTRL.FRCDPLX) bits. Once speed and duplex are determined (either via Auto-Negotiation  
or forced by software), speed is forced by setting the appropriate Speed Selection  
(CTRL.SPEED) bits and duplex is forced by updating the Full Duplex (CTRL.FD) bit.  
• For the 82541xx and 82547GI/EI, configure the LED behavior through LEDCTRL.  
• Link Reset (CTRL.LRST) should be set to 0b (normal). The Ethernet controller defaults to  
LRST = 1b which disables Auto-Negotiation. A transition to 0b initiates the Auto-Negotiation  
function. LRST can be defined in the EEPROM. This bit is only valid in internal SerDes mode  
and has no effect in internal PHY mode.  
1. The 82540EP/EM, 82541xx, and 82547GI/EI do not support any SerDes functionality.  
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• PHY Reset (CTRL.PHY_RST) should be set to 0b. Setting this bit to 1b resets the PHY  
without accessing the PHY registers. This bit is ignored in internal SerDes mode.  
• CTRL.ILOS should be set to 0b (not applicable to the 82541xx and 82547GI/EI).  
• If Flow Control is desired, program the FCAH, FCAL, FCT and FCTTV registers. If not, they  
should be written with 0b. To enable XON frame transmission, the XON Enable  
(FCTRL.XONE) bit must be set. Advertising Flow Control capabilities during the Auto-  
Negotiation process is dependent on whether the Ethernet controller is operating in internal  
SerDes or internal PHY mode. In internal SerDes mode, the TXCW register must be set up  
prior to starting the Auto-Negotiation process. In internal PHY mode, the appropriate PHY  
registers must be set up properly to advertise desired capabilities prior to starting or re-starting  
the Auto-Negotiation process. The Receive Flow Control Enable (CTRL.RFCE) and Transmit  
Flow Control Enable (CTRL.TFCE) bits need to be explicitly set by software in internal PHY  
mode (because Auto-Negotiation is managed by PHY rather than the MAC), or when a fiber  
connection is desired but link was forced rather than Auto-Negotiated.  
• If VLANs are not used, software should clear VLAN Mode Enable (CTRL.VME) bit. In this  
instance, there is no need then to initialize the VLAN Filter Table Array (VFTA). If VLANs  
are desired, the VFTA should be both initialized and loaded with the desired information.  
• For the 82541xx and 82547GI/EI, clear all statistical counters.  
14.4  
Receive Initialization  
Program the Receive Address Register(s) (RAL/RAH) with the desired Ethernet addresses.  
RAL[0]/RAH[0] should always be used to store the Individual Ethernet MAC address of the  
Ethernet controller. This can come from the EEPROM or from any other means (for example, on  
some machines, this comes from the system PROM not the EEPROM on the adapter port).  
Initialize the MTA (Multicast Table Array) to 0b. Per software, entries can be added to this table as  
desired.  
Program the Interrupt Mask Set/Read (IMS) register to enable any interrupt the software driver  
wants to be notified of when the event occurs. Suggested bits include RXT, RXO, RXDMT,  
RXSEQ, and LSC. There is no immediate reason to enable the transmit interrupts.  
If software uses the Receive Descriptor Minimum Threshold Interrupt, the Receive Delay Timer  
(RDTR) register should be initialized with the desired delay time.  
Allocate a region of memory for the receive descriptor list. Software should insure this memory is  
aligned on a paragraph (16-byte) boundary. Program the Receive Descriptor Base Address  
(RDBAL/RDBAH) register(s) with the address of the region. RDBAL is used for 32-bit addresses  
and both RDBAL and RDBAH are used for 64-bit addresses.  
Set the Receive Descriptor Length (RDLEN) register to the size (in bytes) of the descriptor ring.  
This register must be 128-byte aligned.  
The Receive Descriptor Head and Tail registers are initialized (by hardware) to 0b after a power-on  
or a software-initiated Ethernet controller reset. Receive buffers of appropriate size should be  
allocated and pointers to these buffers should be stored in the receive descriptor ring. Software  
initializes the Receive Descriptor Head (RDH) register and Receive Descriptor Tail (RDT) with the  
appropriate head and tail addresses. Head should point to the first valid receive descriptor in the  
descriptor ring and tail should point to one descriptor beyond the last valid descriptor in the  
descriptor ring.  
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Program the Receive Control (RCTL) register with appropriate values for desired operation to  
include the following:  
• Set the receiver Enable (RCTL.EN) bit to 1b for normal operation. However, it is best to leave  
the Ethernet controller receive logic disabled (RCTL.EN = 0b) until after the receive  
descriptor ring has been initialized and software is ready to process received packets.  
• Set the Long Packet Enable (RCTL.LPE) bit to 1b when processing packets greater than the  
standard Ethernet packet size. For example, this bit would be set to 1b when processing Jumbo  
Frames.  
• Loopback Mode (RCTL.LBM) should be set to 00b for normal operation.  
• Configure the Receive Descriptor Minimum Threshold Size (RCTL.RDMTS) bits to the  
desired value.  
• Configure the Multicast Offset (RCTL.MO) bits to the desired value.  
• Set the Broadcast Accept Mode (RCTL.BAM) bit to 1b allowing the hardware to accept  
broadcast packets.  
• Configure the Receive Buffer Size (RCTL.BSIZE) bits to reflect the size of the receive buffers  
software provides to hardware. Also configure the Buffer Extension Size (RCTL.BSEX) bits if  
receive buffer needs to be larger than 2048 bytes.  
• Set the Strip Ethernet CRC (RCTL.SECRC) bit if the desire is for hardware to strip the CRC  
prior to DMA-ing the receive packet to host memory.  
• For the 82541xx and 82547GI/EI, program the Interrupt Mask Set/Read (IMS) register to  
enable any interrupt the driver wants to be notified of when the even occurs. Suggested bits  
include RXT, RXO, RXDMT, RXSEQ, and LSC. There is no immediate reason to enable the  
transmit interrupts. Plan to optimize interrupts later, including programming the interrupt  
moderation registers TIDV, TADV, RADV and IDTR.  
• For the 82541xx and 82547GI/EI, if software uses the Receive Descriptor Minimum  
Threshold Interrupt, the Receive Delay Timer (RDTR) register should be initialized with the  
desired delay time.  
14.5  
Transmit Initialization  
Allocate a region of memory for the transmit descriptor list. Software should insure this memory is  
aligned on a paragraph (16-byte) boundary. Program the Transmit Descriptor Base Address  
(TDBAL/TDBAH) register(s) with the address of the region. TDBAL is used for 32-bit addresses  
and both TDBAL and TDBAH are used for 64-bit addresses.  
Set the Transmit Descriptor Length (TDLEN) register to the size (in bytes) of the descriptor ring.  
This register must be 128-byte aligned.  
The Transmit Descriptor Head and Tail (TDH/TDT) registers are initialized (by hardware) to 0b  
after a power-on or a software initiated Ethernet controller reset. Software should write 0b to both  
these registers to ensure this.  
Initialize the Transmit Control Register (TCTL) for desired operation to include the following:  
• Set the Enable (TCTL.EN) bit to 1b for normal operation.  
• Set the Pad Short Packets (TCTL.PSP) bit to 1b.  
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• Configure the Collision Threshold (TCTL.CT) to the desired value. Ethernet standard is 10h.  
This setting only has meaning in half duplex mode.  
• Configure the Collision Distance (TCTL.COLD) to its expected value. For full duplex  
operation, this value should be set to 40h. For gigabit half duplex, this value should be set to  
200h. For 10/100 half duplex, this value should be set to 40h.  
Program the Transmit IPG (TIPG) register with the following decimal values to get the minimum  
legal Inter Packet Gap:  
Fiber  
(82544GC/EI  
Copper  
(82544GC/EI  
Fiber  
Copper  
IPGT  
IPGR1  
IPGR2  
10  
10  
10  
10  
10  
10  
6
8
8a  
6a  
8a  
6a  
a.  
Applicable to the 82541xx and 82547GI/EI.  
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Note: IPGR1 and IPGR2 are not needed in full duplex, but are easier to always program to the values  
shown.  
Table 14-1. Signal Descriptions  
Signal  
Ball  
Name and Function  
Loss of Signal (TBI) / Link Indication. Loss of signal (high for lost  
signal) from the optical transceiver when LINK_MODE equals 11b;  
active high link indication from PHY in GMII/MII mode.  
LOS / LINK  
A10  
C7  
D7  
E6  
B5  
E5  
C5  
E4  
C4  
D5  
D4  
TX_DATA[9] / TX_ER  
TX_DATA[8] / TX_EN  
TX_DATA[7]  
TX_DATA[6]  
TX_DATA[5]  
TX_DATA[4]  
TX_DATA[3]  
TX_DATA[2]  
TX_DATA[1]  
Transmit Data.  
TBI: TX_DATA[9:0] for transmit data bus.  
GMII: TX_DATA[7:0] for transmit data bus.  
TX_ER forces propagation of transmit errors and is used for carrier  
extension. TX_EN is asserted to indicate transmission of data on the  
interface.  
MII: TX_DATA[3:0] for transmit data bus.  
TX_ER is not used. TX_EN is used for transmit enable signal.  
TX_DATA[0]  
Transmit Clock.  
TBI: 125 MHz transmit clock.  
GMII: Operates at 125 MHz.  
MII: Undefined.  
GTX_CLK  
EWRAP  
C6  
Enable Wrap.  
TBI: EWRAP is low in normal operation. When it is high, the SerDes  
device is forced to transceiver loopback the serialized transmit data  
to the receiver.  
This pin is tri-stated during EEPROM read. In order to avoid a  
floating input in an external SerDes, a weak external pull-down  
should be connected to this pin.  
E10  
GMII / MII: Not used.  
Collision.  
TBI: Undefined.  
GMII / MII: This signal indicates that a collision was detected on the  
medium by the PHY. This signal remains asserted while the collision  
persists. For half-duplex transceivers, this signal indicates  
simultaneous transmission and reception. This signal is ignored in  
full-duplex mode.  
COL  
E7  
Normal Mode: This signal must be connected to VSS except for test  
mode.  
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Signal  
Ball  
Name and Function  
Carrier Sense.  
TBI: Undefined.  
GMII / MII: This signal indicates traffic activity on the cable, either  
incoming or outgoing. This signal is driven by the PHY. CS is not  
required to transition synchronously with respect to the RX or TX  
clocks. This signal is ignored in full-duplex mode.  
Normal Mode: This signal must be connected to VSS except for test  
mode.  
CRS  
A6  
A9  
D10  
B9  
C9  
D9  
E9  
E8  
C8  
A7  
B7  
RX_DATA[9] / RX_ER  
RX_DATA[8] / RX_DV  
RX_DATA[7]  
RX_DATA[6]  
RX_DATA[5]  
RX_DATA[4]  
RX_DATA[3]  
RX_DATA[2]  
RX_DATA[1]  
Receive Data.  
TBI: RX_DATA[9:0] for receive data bus  
GMII: RX_DATA[7:0] for receive data bus.  
RX_ER signals a receive error. RX_DV is asserted to indicate data is  
valid on the interface.  
MII: RX_DATA[3:0] for receive data bus.  
RX_ER signals a receive error. RX_DV indicates data is valid on the  
interface.  
RX_DATA[0]  
Receive Clock 0.  
TBI: RBC0 is receive clock (62.5 Mbps).  
GMII: RX_CLK is receive clock (125 Mbps).  
MII: RX_CLK is receive clock for 100 Mbps operation (25 Mbps) and  
for 10 Mbps operation (2.5 Mbps).  
RBC0 / RX_CLK  
C11  
14.5.1  
Signal Interface  
The external GMII/MII interface is similar in function to the interface used to communicate  
between the MAC and internal PHY. As with use of the internal PHY, the external GMII/MII  
interface supports 10/100/1000 Mbps operation, with both half- and full-duplex operation at 10/  
100 Mbps, and full-duplex operation at 1000 Mbps. Unlike the communication path to the internal  
PHY, the external interface does not provide certain additional control/status interfaces for  
automatic hardware link setup and/or power-management  
Table 14-2lists the signals, functions, and pins used to provide this interface.  
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Table 14-2. Signal Functions  
Signal  
Function  
Pin  
GMII (1000 Mbps) Operations  
CRS  
Carrier Sense  
CRS  
COL  
Collision Detect  
COL  
TX_ER  
TX_EN  
GTX_CLK  
TX_DATA  
RX_CLK  
RX_DATA  
RX_ER  
RX_DV  
LINK  
Transmit Code Error  
Transmit Enable  
TX_DATA[9]/TX_ER  
TX_DATA[8]/TX_EN  
GTX_CLK  
Transmit Data Clock (125 MHz)  
Transmit Data  
TX_DATA[7:0]  
RBC0/RX_CLK  
RX_DATA[7:0]  
RX_DATA[9]/RX_ER  
RX_DATA[8]/RX_DV  
LOS/LINK  
Receive Data Clock (125 MHz)  
Receive Data  
Receive Error  
Receive Data Valid  
PHY Link Indication  
MII (10/100 Mbps) Differences  
MTX_CLK  
TX_DATA  
RX_CLK  
Transmit Data Clock (25/2.5 MHz)  
RBC1/MTX_CLK  
TX_DATA[3:0]  
RBC0/RX_CLK  
RX_DATA[3:0]  
Transmit Data  
Receive Data Clock (25/2.5 MHz)  
Receive Data  
RX_DATA  
14.5.2  
GMII/MII Features not Supported  
Table 14-3 lists the signals and functions not provided by this interface.  
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Table 14-3. Signal Functions Not Supported  
Signal  
Function  
Ramifications  
MII Management Interface (PHY Register Access)  
MDC  
Management Data Clock  
Management Data I/O  
No support/access to MII register set.  
MDI/O  
Direct PHY Indications to MAC  
Can limit use to specific known duplex  
setting.  
FDX  
PHY-negotiated full/half duplex indication  
PHY-negotiated speed (10/100/1000 Mbps)  
Can limit use to specific known speed or  
require use of auto-speed detection.  
SPD_IND  
14.5.3  
14.5.4  
Avoiding GMII Test Mode(s)  
Note that the Ethernet controller contains a set of test modes that use this interface for component  
manufacturing and/or diagnostic test. To avoid accidental engagement of unexpected test mode(s)  
when using the external GMII (or TBI), the TEST_GMII[2:0] test pins must remain de-asserted  
(low) and the TEST_DM_N pin must remain de-asserted (high).  
MAC Configuration  
The Ethernet controller MAC operates in a GMII/MII mode when operating with the internal PHY;  
this mode is similar to the GMII/MII mode of the standalone 82543 MAC components and others.  
In GMII/MII mode, the MAC operates assuming use of a GMII/MII interface communication,  
variable duplex & speed configuration (unless forced or auto-detected). For the Ethernet  
controller, to use this external interface as a GMII/MII interface and have the MAC operate in this  
GMII/MII Mode, the LINK_MODE must be set to 01b.  
It is likely that the MAC might be required to be configured in a forced-duplex configuration, as no  
means is provided (either the MDI/O access or direct PHY-to-MAC signaling) of any duplex  
configuration that might be negotiated between the attached Ethernet controller/transceiver and its  
link partner.  
The MAC can further be required to be configured in a forced-speed configuration, as no direct  
speed indication is available via the external interface (compared to the SPD_IND signals provided  
by the internal PHY). The Auto-Speed detection (ASD) can be potentially useful in automatically  
calculating and configuring a speed setting based in the interface signals that are provided.  
The MAC is unable to provide any access to MII Management registers through the MDIC register,  
as no explicit MDI/O signals are included in this interface. However, it is possible that software-  
definable pins (SDP) can be capable of providing the necessary access capability.  
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14.5.5  
Link Setup  
The following examples are provided as suggestions for configuring common settings between the  
MAC and an Ethernet controller attached in the GMII/MII mode.  
 MAC duplex and speed settings forced by software based on resolution of PHY  
(CTRL.FRCDPLX = 1b, CTRL.FRCSPD = 1b, CTRL.ASDE = don’t care)  
CTRL.FD Set by software based on reading PHY status register after  
PHY has autonegotiated a successful link-up.  
CTRL.SLU Must be set to 1b by software to enable communications  
between MAC and PHY  
CTRL.RFCE Must be set by S/W after reading flow control resolution from  
PHY registers  
CTRL.TFCE - Must be set by S/W after reading flow control resolution from PHY registers  
CTRL.SPEED Set by software based on reading PHY status register after  
PHY has autonegotiated a successful link-up.  
STATUS.FD Reflects the MAC forced duplex setting written to CTRL.FD  
STATUS.LU Reflects link indication (LINK) from PHY qualified with  
CTRL.SLU (set to 1b)  
STATUS.SPEED Reflects MAC forced speed setting written in  
CTRL.SPEED  
 MAC duplex setting forced by software based on resolution of PHY; speed auto-detected by  
MAC  
(CTRL.FRCDPLX = 1b, CTRL.FRCSPD = 0b, CTRL.ASDE = 1b)  
CTRL.FD Set by software based on reading PHY status register after  
PHY has autonegotiated a successful link-up.  
CTRL.SLU Must be set to 1b by software to enable communications  
between MAC and PHY  
CTRL.RFCE Must be set by S/W after reading flow control resolution from  
PHY registers  
CTRL.TFCE ..............  
registers  
Must be set by S/W after reading flow control resolution from PHY  
CTRL.SPEED Don’t care; speed setting is calculated by the MAC based  
on signals from the PHY after PHY has autonegotiated a successful  
link-up  
STATUS.FD Reflects the MAC forced duplex setting written to CTRL.FD  
STATUS.LU Reflects link indication (LINK) from PHY qualified with  
CTRL.SLU (set to 1b)  
STATUS.SPEED Reflects actual speed setting calculated by MAC ASD  
function  
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 MAC/PHY duplex and speed settings both forced by software (fully-forced link setup)  
(CTRL.FRCDPLX = 1b, CTRL.FRCSPD = 1b, CTRL.SLU = 1b)  
CTRL.FD ...................Set by software to desired full/half duplex operation (must match  
duplex setting of PHY)  
CTRL.SLU.................Must be set to 1b by software to enable communications between MAC  
and PHY. PHY must also be forced/configured to indicate positive link  
indication (LINK) to the MAC  
CTRL.RFCE ..............Must be set by S/W to desired flow-control operation (must match flow-  
control settings of PHY)  
CTRL.TFCE ..............Must be set by S/W to desired flow-control operation (must match flow-  
control settings of PHY)  
CTRL.SPEED............Set by software to desired link speed (must match speed setting of  
PHY)  
STATUS.FD...............Reflects the MAC duplex setting written by software to CTRL.FD  
STATUS.LU...............Reflects 1b (positive link indication LINK from PHY qualified with  
CTRL.SLU). Note: since both CTRL.SLU and the PHY link indication  
LINK are forced, this bit set does not GUARANTEE that operation of  
the link has been truly established.  
STATUS.SPEED........Reflects MAC forced speed setting written in CTRL.SPEED  
Note: It is important to note that for the Ethernet controller’s link indication (LINK) to be noted by the  
MAC, the MAC control bit CTRL.SLU must be set to 1b. Normal MAC/PHY speed and duplex  
configuration are based on observing events on this link indication from the Ethernet controller.  
14.6  
PHY Initialization (10/100/1000 Mb/s Copper Media)  
Software needs to determine the PHY address at which the PHY actually resides. This number can  
be anywhere from 0 to 31.The PHY address is programmable. Board designers can then choose at  
what PHY address the PHY resides. Software needs to identify the PHY address so that the PHY  
can be accessed successfully.  
To accomplish read and write access to any of the PHY registers, software must program the MDI  
Control Register (MDIC) with the appropriate data. A PHY is reset at power-up and is enabled to  
Auto-Negotiate by default. Typically in most environments, by the time the software driver is  
loaded, the Auto-Negotiation process has completed. However, the PHY might or might not  
advertise the appropriate capabilities desired by the design. In this instance, it is up to the software  
to insure that the PHY registers are set up properly to advertise the appropriate Ethernet controller  
capabilities. For example, by default the Ethernet controller advertises no flow control capabilities  
in its Auto-Negotiation Advertisement Register (MII Register 4). In order to advertise TX and/or  
RX Pause capabilities, this register must be modified and Auto-Negotiation re-started to advertise  
these capabilities to the link partner.  
The MII Status Register (PHY Register 1) should be used to check link status.  
Software can also force the speed/duplex of a PHY via MII/GMII register access. Note that forcing  
gigabit speed in a copper environment is not allowed per IEEE specification. Only 10/100 speed  
and duplex should be forced in the PHY.  
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General Initialization and Reset Operation  
Once link is achieved by the PHY, software is notified when a Link Status Change (LSC) interrupt  
is generated by the Ethernet controller. This only occurs if software enabled the LSC bit in the  
Interrupt Mask Set/Read (MS) Register.  
14.7  
Reset Operation  
The following reset signals affect the Ethernet controller in different ways. RST# is the only  
external signal. Other reset events are asserted by performing slave writes to specific bits in the  
control registers.  
Values indicated as “?” imply the default value is either unknown or is read from the EEPROM.  
Note: In situations where the TX block is reset, the TX data lines are forced to all 0b’s. This causes a  
substantial number of symbol errors to be detected by the link partner. In TBI mode (82544GC/  
EI)/internal SerDes (82546GB/EB and 82545GM/EM), if the duration is long enough, the link  
partner can restart the Auto-Negotiation process by sending “break-link” (/C/ codes with the  
configuration register value set to all 0b’s).  
LAN_PWR_GOOD:  
Deasserting LAN_PWR_GOOD resets all resettable registers in the Ethernet controller. The signal  
is level-sensitive, and the Ethernet controller is held in reset until LAN_PWR_GOOD is asserted.  
While asserted, all PCI signals are forced to a high impedance state.  
General Registers:  
Interrupt Registers:  
Receive Registers:  
Reset to power-on values.  
Reset to power-on values.  
Reset to power-on values (exceptions are the RAH/RAL, MTA, VFTA  
and RDBAH/RDBAL registers, which are not reset to any preset  
value. The valid bit of the RAH register is cleared).  
Reset to power-on values (exceptions are the TDBAH/TDBAL regis-  
ters, which are not reset to any preset value).  
Reset to power-on values.  
The WUC (except for the PME_En and PME_Status bits if  
AUX_POWER = 1b), WUFC, IPAV, and FFLT registers are reset to  
their default value.  
Transmit Registers:  
Statistics Registers:  
Wakeup Registers:  
Diagnostic Registers:  
Reset to power-on values (exception is the PBM memory, which is not  
reset to any preset value).  
PCI Config Space:  
PHY:  
Context Lost; requires initialization.  
RST# is asserted to reset the PHY while LAN_PWR_GOOD is deas-  
serted.  
In addition, the Ethernet controller automatically reads certain values from the EEPROM and  
configures itself to use those EEPROM settings.  
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General Initialization and Reset Operation  
RST#:  
When asserted, all PCI signals are forced to a high impedance state. Upon deassertion, the Ethernet  
controller’s internal registers, excluding the following exceptions, are reset.  
General Registers:  
Interrupt Registers:  
Receive Registers:  
Reset to power-on values.  
Reset to power-on values.  
Reset to power-on values (exceptions are the RAH/RAL, MTA,  
VFTA and RDBAH/RDBAL registers, which are not reset to any  
preset value. The valid bit of the RAH register is cleared).  
Transmit Registers:  
Reset to power-on values (exceptions are the TDBAH/TDBAL,  
and TIPG registers, which is not reset to any preset value).  
Statistics Registers:  
Wakeup Registers:  
Reset to power-on values.  
The WUC (except for the PME_En and PME_Status bits if  
AUX_POWER = 1b), WUFC, IPAV, and FFLT registers are reset  
to their default value.  
Diagnostic Registers:  
PCI Config Space:  
Reset to power-on values (exception is the PBM memory, which is  
not reset to any preset value).  
Context Lost; requires initialization. If AUX_POWER = 1b then  
the PME_En and PME_Status bits of the Power Management  
Control/Status Register are preserved.  
PHY:  
RST# is asserted for 400 ns after deassertion of RST#.  
Asserting RST# puts the Ethernet controller into the “Dr” Power Management state. See Section  
6.3.1.1 for details on the power states, and Section 6.3.2.4 for reset related timing.  
Deasserting RST# also causes the EEPROM to be re-read and the registers that get values from the  
EEPROM to be re-loaded.  
Global Reset:  
Bit 26 of the Device Control Register (CTRL.RST) performs an Ethernet controller reset of all  
functions to their equivalent power on state similar to asserting RST#, except that the state of the  
PCI core and PCI configuration space is not affected.  
General Registers:  
Interrupt Registers:  
Receive Registers:  
Reset to power-on values.  
Reset to power-on values.  
Reset to power-on values (exceptions are the RAH/RAL, MTA, VFTA  
and RDBAH/RDBAL registers, which are not reset to any preset  
value. The valid bit of the RAH register is cleared).  
Reset to power-on values (exceptions are the TDBAH/TDBAL, and  
TIPG registers).  
Transmit Registers:  
Statistics Registers:  
Wakeup Registers:  
Reset to power-on values.  
The WUC (except for the PME_En and PME_Status bits), WUFC,  
IPAV, and FFLT registers are reset to their default value.  
Reset to power-on values (exception is the PBM memory, which is not  
reset to any preset value).  
Diagnostic Registers:  
PCI Config Space:  
PHY:  
No Change.  
No effect.  
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General Initialization and Reset Operation  
Default values for certain bits of the Device Control Register must be read out of the EEPROM and  
appropriately set by software if an EEPROM is used.  
Global Reset does NOT affect the direction of the software programmable pins.  
Link_Reset:  
When LRST (bit 3 of the Device Control register) is written as a logic 1b, the Ethernet controller is  
forced into a link reset state. When LRST is set to 1b the Auto-Negotiation function is disabled.  
The Auto-Negotiation logic is initiated/restarted when LRST is transitions to 0b. A link reset is  
only relevant in TBI mode/internal SerDes (not applicable to the 82540EP/EM, 82541xx and  
82547GI/EI).  
The transmitter sends /C/ ordered_sets when LRST is asserted.  
General Registers:  
Interrupt Registers:  
Receive Registers:  
Transmit Registers:  
Statistics Registers:  
Wakeup Registers:  
Diagnostic Registers:  
PHY:  
No change.  
No change.  
The RXCW register is cleared.  
No change.  
No change.  
No change.  
No change.  
No effect.  
EE_RST (Extended Device Control Register):  
EEPROM reset bit. Initiates a “reset-like” event to the EEPROM function that causes the  
EEPROM to be read again. Control registers bits are not affected other than those read from the  
EEPROM.  
PHY_RST (Device Control Register):  
PHY reset bit in the Device Control Register. By writing a 1b to this bit the software forces the  
assertion of an internal signal output to reset the PHY device without accessing the PHY registers  
through the MII management interface (MDI/O & MDC). Internal states of the Ethernet controller  
are not impacted. To release the PHY reset the software must write a 0b to the bit.  
In situations where the Ethernet controller is reset using the software reset CTRL.RST, the TX data  
lines are forced to all 0b’s. This causes a substantial number of symbol errors to be detected by the  
link partner. In TBI mode/internal SerDes, if the duration is long enough, the link partner can  
restart the Auto-Negotiation process by sending “break-link” (/C/ codes with the config register  
value set to all 0b’s).  
Some registers mentioned above within the Ethernet controller are treated specially. The RAH/  
RAL[n], MTA[n], VFTA[n], WUPM[n], FFMT[n], FFVT[n], TDBAH/TDBAL, and RDBAH/  
RDBAL registers have no default value and if the functions associated with the registers are  
enabled they must be programmed by software. Once programmed, their value is preserved  
through all resets as long as power is applied to the Ethernet controller. Bit 31, the valid bit, of the  
RAH[n] registers is the exception and is reset with the LAN_PWR_GOOD and RST# and software  
reset (CTRL.RST) bit.  
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General Initialization and Reset Operation  
Driver accessible Wakeup Status registers are excluded from all resets except for  
LAN_PWR_GOOD. This includes:  
• Wakeup Status Register.  
• Wakeup Packet Length.  
• Wakeup Packet Memory.  
Finally, the “Wakeup Context” as defined in the PCI Bus Power Management Interface  
Specification is reset on LAN_PWR_GOOD, and is also reset on the deassertion of RST# if  
AUX_POWER = 0b. This includes:  
• PME_En bit of the Power Management Control/Status Register (PMCSR).  
• PME_Status bit of the Power Management Control/Status Register (PMCSR).  
The shadow copies of these bits in the Wakeup Control Register are treated identically.  
14.8  
Initialization of Statistics  
Statistics registers are hardware-initialized to values as detailed in each particular register’s  
description. The initialization of these registers begins upon transition to D0  
power state  
active  
(when internal registers become accessible, as enabled by setting the Memory Access Enable of the  
PCI Command register), and is guaranteed to be completed within 1 µs of this transition. Access to  
statistics registers prior to this interval can return indeterminate values. Given typical system boot  
times and the software driver’s Ethernet controller initialization routines, no initialization of these  
registers through software should be necessary.  
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Diagnostics and Testability  
15  
15.1  
Diagnostics  
This section explains the registers provided for diagnostic access.  
These registers enable system level integration and debugging, including the ability to access all  
internal memories. This information is often critical in determining failure modes and in  
developing software workarounds.  
At a diagnostic level, all of the major internal data structures visible to and controllable by  
software, including all of the FIFO space. However, interlocks are not provided for any operations,  
so diagnostic accesses need to be performed under very controlled circumstances.  
15.1.1  
FIFO State  
The internal data FIFO pointers are visible through the head and tail diagnostic data FIFO registers  
(see Section 13.8). Diagnostics software uses these FIFO pointers to confirm correct operation and  
to directly write packets into, or directly read out of, the FIFO.  
These registers are available for diagnostic purposes only and should not be written during normal  
operation.  
15.1.2  
15.1.3  
FIFO Data  
All of the FIFO data is visible through the PBM register. Locations can be accessed as 32-bit or 64-  
bit words. Refer to Section 13.8.11 for details.  
Loopback  
One loopback mode is provided in the Ethernet controller to assist with system and device debug.  
This loopback mode is enabled via RCTL.LBM control bits. The Ethernet controller must be  
operating in full-duplex mode for loopback.  
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Diagnostics and Testability  
15.1.3.1  
Internal Loopback  
This loopback mode internally loops back the transmit to receive path in the PHY, exercising the  
internal GMII/MII bus. Programming both MAC and PHY is required. Following is the flow:  
/* Auto-MDI/MDIX Off */  
e1000_write_phy_reg(16, 0x0808);  
/* reset to update Auto-MDI/MDIX */  
e1000_write_phy_reg(0, 0x9140);  
/* autoneg off */  
e1000_write_phy_reg(0, 0x8140);  
/* force 1000, set loopback */  
e1000_write_phy_reg(0, 0x4140);  
/* Now set up the MAC to the same speed/duplex as the PHY. */  
ctrl_reg = E1000_READ_REG(CTRL);  
ctrl_reg &= ~E1000_CTRL_SPD_SEL;  
ctrl_reg |= (E1000_CTRL_FRCSPD |  
E1000_CTRL_FRCDPLX |  
/* Clear the speed sel bits */  
/* Set the Force Speed Bit */  
/* Set the Force Duplex Bit */  
/* Force Speed to 1000 */  
E1000_CTRL_SPD_1000 |  
E1000_CTRL_FD);  
/* Force Duplex to FULL */  
/* Set the ILOS bit on the fiber Nic is half duplex link is detected. */  
stat_reg = E1000_READ_REG(STATUS);  
if((stat_reg & E1000_STATUS_FD) = 0)  
ctrl_reg |= (E1000_CTRL_ILOS | E1000_CTRL_SLU);  
E1000_WRITE_REG(CTRL, ctrl_reg);  
15.2  
Testability  
The Ethernet controller uses full Boundary Scan/IEEE 1149.1 JTAG standard test methods. The  
TAP controller supports EXTEST, SAMPLE/PRELOAD, IDCODE, USERCODE, and BYPASS  
instructions.  
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Diagnostics and Testability  
15.2.1  
15.2.2  
15.2.3  
EXTEST Instruction  
This instruction allows testing of off-chip circuitry and board level interconnections. Data is  
typically loaded onto the latched parallel outputs of the boundary-scan shift register stages using  
the SAMPLE/PRELOAD instruction prior to selection of the EXTEST instruction.  
SAMPLE/PRELOAD Instruction  
This mandatory instruction allows a snapshot of the normal operation of the component to be taken  
and examined. It also allows data values to be loaded onto the latched parallel outputs of the  
boundary-scan shift register prior to selection of the other boundary-scan test instructions.  
IDCODE Instruction  
The IDCODE instruction provides information on the base component. When an Ethernet  
controller identification register is included in a component design, the IDCODE instruction is  
forced into the instruction register’s parallel output latches.  
For example, the 82546EB controller’s ID is determined and derived from the manufacturer as  
follows:  
Component  
Product Code  
ID Code  
(hex)  
Ver  
V
Product  
Gen  
0010  
Model  
Manf ID  
1
82546EB  
0001  
1
001001  
00100 00000001001  
1
19244013  
15.2.4  
BYPASS Instruction  
This instruction is the only instruction defined by the standard that causes operation of the bypass  
register. The bypass register contains a single-shift register stage and is used to provide a minimum  
length serial path between the TDI and TDO pins of a component when no test operation of that  
component is required. This allows more rapid movement of test data to and from other  
components on a board that are required to perform test operations.  
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Appendix (Changes From 82544EI/82544GC)  
A
A.1  
Introduction  
This section describes the new features that have been added to the PCI/PCI-X Family of Gigabit  
Ethernet Controllers from its predecessor, the 82544EI/82544GC and highlights its registers that  
have been changed.  
A.2  
New Features  
Following is a list of the new features in the Ethernet controller, along with sections in this manual  
that describe these features in detail:  
• Integrated dual-port solution. The 82546GB/EB architecture includes two instances of both  
the MAC and PHY. The Ethernet controller contains a single PCI/PCI-X interface so that each  
of the logical LAN devices appear as a distinct PCI/PCI-X bus device (see Chapter 12).  
• IPv6 Support. The Ethernet controller supports IP/TCP/UDP receive checksum offload for  
IPv6 packets, IPv6 wakeup filters, and IPv6 TCP segmentation (see Chapter 3).  
• Improved Interrupts. The Ethernet controller has the following new interrupt generation  
features to enhance driver performance:  
— Packet timers and absolute delay timers for transmit and receive (see Section 3.2.7).  
— Short packet detection interrupts (see Section 3.2.7).  
— Transmit descriptor low interrupts (see Section 3.4.3).  
— Interrupt throttling control to limit maximum interrupt rate (see Section 13.4.8).  
— Acknowledge interrupts by writing 1b’s to the ICR (see Section 13.4.17).  
• EEPROM access. Because the 82546GB/EB has two MAC/PHY instances that could  
potentially access the EEPROM at the same time, a semaphore has been added to gate access.  
In addition, the EERD now allows easy EEPROM access (see Section 12.3.2).  
• Manageability. The Ethernet controller introduces manageability for ASF 1.0 and AOL 2.0.  
• Configurable LED. The Ethernet controller enables software to customize LED displays (see  
Chapter 10).  
• Power Management. The internal copper PHY features 10/100/1000-BaseT signalling and is  
capable of performing intelligent power-management based on both the system power-state  
and LAN energy-detection (detection of unplugged cables). See Chapter 6.  
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Appendix (Changes From 82544EI/82544GC)  
A.3  
Register Changes  
Table A-1 lists the registers that have been added or changed in the Ethernet controller.  
Table A-1. Register Changes  
Register  
Offset  
CTRL  
00000h  
00008h  
00010h  
00014h  
00018h  
00E00h  
000C0h  
000C4h  
000C8h  
000D0h  
000D8h  
02820h  
02828h  
0282Ch  
02C00h  
05000h  
03828h  
0382Ch  
040D4h  
040D8h  
040DCh  
040E0h  
040E4h  
040E8h  
040ECh  
040F0h  
040F4h  
STATUS  
EEC  
EERD  
CTRL_EXT  
LEDCTL  
ICR  
ITR  
ICS  
IMS  
IMC  
RDTR  
RXDCTL  
RADV  
RSRPD  
RXCSUM  
TXDCTL  
TADV  
TPT  
PTC64  
PTC127  
PTC255  
PTC511  
PTC1023  
PTC1522  
MPTC  
BPTC  
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Appendix (82540EP/EM and 82545GM/EM  
Differences)  
B
B.1  
B.2  
Introduction  
This section describes the differences between the 82546GB/EB, the 82540EP/EM and the  
82545GM/EM. All three of these Ethernet controllers come from the same family so their register  
sets are essentially the same. The sections that follow describe the differences between the  
82546GB/EB and the 82540EP/EM or 82545GM/EM, and resulting register differences and  
developer impact.  
82540EP/EM Differences  
Below are the differences between the 82540EP/EM and the 82546GM/EM:  
• Serial FLASH interface. The 82540EP/EM does not support a parallel FLASH interface.  
• No TBI/internal SerDes interface. The 82540EP/EM provides internal GMII / MII  
interfaces only  
• Single-port functionality. The dual-port functionality of the 82546GB/EB is not included.  
• 32-bit PCI support only. The 82540EP/EM does not support 64-bit PCI or PCI-X.  
• Internal SerDes. The 82540EP/EM does not support internal SerDes.  
The impact to registers and the developer are outlined in the following sections.  
B.2.1  
Serial FLASH Interface  
The 82540EP/EM provides an external interface to a serial Flash or Boot EPROM device.  
Hardware implements a serial command set compatible with the Atmel AT25-series devices in the  
512 Kb (64 KB) thru 1024 Kb (128 KB) sizes. The size of the FLASH used with the 82540EP/EM  
should be encoded into bits in EEPROM to configure the amount of address space required when  
mapped. All accesses to this device are controlled by hardware and are accessible to software as  
normal PCI reads or writes to the FLASH memory mapping range. The FLASH and Expansion  
ROM BARs are reconfigured based on these EEPROM settings.  
Note: The 82540EP/EM serial FLASH controller supports reads from programmed FLASH devices, and  
writes to erased FLASH devices. Chip and sector-erase commands are not supported. It is  
recommended that FLASH devices be socketed to enable removal for re-programming if  
necessary.  
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Appendix (82540EP/EM and 82545GM/EM Differences)  
Note: Though the 82540EP/EM supports devices with up to 512 KB of memory, smaller devices may  
also be used. Accesses to memory beyond the FLASH device size results in access wrapping as  
only the lower address bits are utilized by the FLASH.  
The 82540EP/EM does not provide an interface for performing an “Erase” operation to the serial  
Flash device. Flash write operations must be performed to an initialized or pre-erased Flash device.  
If in-circuit erase is required, an external source (such as hardware's software-definable pins) can  
be used to drive the Flash pins to perform the erase operation.  
B.2.2  
B.2.3  
No TBI/Internal SerDes Interface  
The 82540EP/EM does not support a TBI/internal Serdes interface. As a result, all TBI/internal  
SerDes-related registers (for example, RXCW) should not be used.  
Single-Port Functionality  
The 82540EP/EM and the 82545GM/EM do not have the dual-port functionality of the  
82546GB/EB. As a result, the 82540EP/EM and the 82545GM/EM appear as single PCI bus  
devices.  
B.2.4  
32-Bit PCI Support  
No developer impact.  
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