Intel PCI-X, Intel Gigabit Ethernet Controllers Shared Eeprom, Eeprom Map, Eeprom Arbitration

Dual Port Characteristics

12.3Shared 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.

12.3.1EEPROM 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
Ethernet Address (IA)	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
(LAN A/B shared)
	same EEPROM word, and is set to the value of {Ethernet IA LAN A with its
	least significant bit inverted}.
Initialization Control 1,	These EEPROM words specify hardware-default values for parameters that
Initialization Control 2	apply a single value to both LAN devices, such as link configuration
	parameters required for auto-negotiation, wakeup settings, PCI/PCI-X bus
(LAN A/B shared)
	advertised capabilities, etc.
	This EEPROM word configures default values associated with each LAN
	device’s hardware connections, including which link mode (internal PHY,
Initialization Control 3	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
(LAN A, LAN B unique)
	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.
	This EEPROM word configures manageability parameters. Note that this word
	controls whether an internal ASF controller is enabled/disabled for this LAN,
Management Control	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.

12.3.2EEPROM 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.

206 Software Developer’s Manual