Dual Port Characteristics

Byte Offset

Byte 0

 

Byte 1

 

Byte 2

Byte 3

 

 

 

 

 

 

24h

 

 

Base Address 5

 

 

 

 

 

 

28h

 

 

Cardbus CIS Pointer (not used)

 

 

 

 

 

 

 

2Ch

 

Subsystem ID

 

Subsystem Vendor ID

 

 

 

 

 

 

30h

 

 

Expansion ROM Base Address

 

 

 

 

 

 

 

 

34h

 

 

Reserved

 

 

Cap_Ptr

 

 

 

 

 

 

38h

 

 

 

Reserved

 

 

 

 

 

 

 

 

3Ch

Max_Latency 00h

Min_Grant

 

Interrupt Pin

Interrupt Line

FFh

 

01h or 00h)

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

only a single value can be specified. The value is reflected identically for both

 

LAN devices.

 

 

Revision

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

Header Type

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”.

 

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,

Subsystem ID

but only a single value can be specified. The value is reflected identically for

 

both LAN devices.

 

 

 

The Subsystem Vendor ID of the Ethernet controller can be specified via

Subsystem Vendor ID

EEPROM, but only a single value can be specified. The value is reflected

 

identically for both LAN devices.

 

 

Class Code,

 

Cap_Ptr,

These fields reflect fixed values that are constant values reflected for both LAN

Max Latency,

devices.

Min Grant

 

 

 

204

Software Developer’s Manual

Page 218
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Intel Intel Gigabit Ethernet Controllers, PCI-X manual 204