82801BA Datasheet, PDF (79/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Functional Description
5.2.4 Serial EEPROM Interface
The serial EEPROM stores configuration data for the ICH2 integrated LAN Controller and is a
serial in/serial out device. The LAN Controller supports a 64 word size or 256 register size
EEPROM and automatically detects the EEPROM’s size. A 256 word EEPROM device is required
for a Cardbus system and contains the CIS information. The EEPROM should operate at a
frequency of at least 1 MHz.
All accesses, either read or write, are preceded by a command instruction to the device. The
address field is six bits for a 64 word EEPROM or eight bits for a 256 register EEPROM. The end
of the address field is indicated by a dummy zero bit from the EEPROM, which indicates the entire
address field has been transferred to the device. An EEPROM read instruction waveform is shown
in Figure 5-5.
Figure 5-5. 64-Word EEPROM Read Instruction Waveform
EE_SHCLKK
EE_CS
EE_DIN
EE_DOUT
A₅
A₄
A₃
A₂
AA₁₀ A₀
READ OP code
D₁₅
D₀
The LAN Controller performs an automatic read of seven words (0h, 1h, 2h, Ah, Bh, Ch and Dh) of
the EEPROM after the deassertion of Reset. The ICH2 integrated LAN Controller’s EEPROM
format is shown below in Table 5-2. For additional information, refer to Application Note AP-409,
"I/O Controller Hub EEPROM Map and Programming Information"
82801BA ICH2 and 82801BAM ICH2-M Datasheet
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