Intel PCI User Manual

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206
Software Developer’s Manual
Dual Port Characteristics
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:
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.
Ethernet Address (IA)
(LAN A/B shared)
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 
least significant bit inverted}.
Initialization Control 1,
Initialization Control 2
(LAN A/B shared)
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 3
(LAN A, LAN B unique)
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.
Management Control
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.