Intel PCI User Manual

95

Note: These Ethernet controllers also provide identification data through the Test Access Port (TAP).

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 

EEPROM devices

1

. 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.

82541GI-B1

8086h

1076h

Cooper

82541GI-B1

8086h

1077h

Mobile

82541PI-C0

8086h

1076h

Cooper

82541ER-C0

8086h

1078h

Cooper

82540EP-A

8086h

1017

Desktop

82540EP-A

8086h

1016

Mobile

82540EM-A

8086h

100E

Desktop

82540EM-A

8086h

1015

Mobile

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.