Table 2.7

Mode A Serial EEPROM Data Format

 

 

 

 

Byte

 

Name

Description

 

 

 

 

0xFB

 

SVID(0)

Subsystem Vendor ID, LSB. This byte is loaded into the least significant

 

 

 

byte of the Subsystem Vendor ID register in the appropriate PCI

 

 

 

configuration space at chip power-up.

 

 

 

 

0xFC

 

SVID(1)

Subsystem Vendor ID, MSB. This byte is loaded into the most significant

 

 

 

byte of the Subsystem Vendor ID register in the appropriate PCI

 

 

 

configuration space at chip power-up.

 

 

 

 

0xFD

 

SID(0)

Subsystem ID, LSB. This byte is loaded into the least significant byte of

 

 

 

the Subsystem ID register in the appropriate PCI configuration space at

 

 

 

chip power-up.

 

 

 

 

0xFE

 

SID(1)

Subsystem ID, MSB. This byte is loaded into the most significant byte of

 

 

 

the Subsystem ID register in the appropriate PCI configuration space at

 

 

 

chip power-up.

 

 

 

 

0xFF

 

CKSUM

Checksum. This 8-bit checksum is formed by adding, bytewise, each byte

 

 

 

contained in locations 0x00–0x03 to the seed value 0x55, and then taking

 

 

 

the 2s complement of the result.

 

 

 

0x100–0xEOM

UD

User Data.

 

 

 

 

2.4.2 No Download Mode

When MAD7 is pulled up through an external resistor, the automatic download is disabled and no data is automatically loaded into chip registers at power-up. The Subsystem ID and Subsystem Vendor ID registers are read only, per the PCI specification, with a default value of 0x1000 and 0x1000 respectively.

2.5 Power Management

The LSI53C875A complies with the PCI Bus Power Management Interface Specification, Revision 1.1. The PCI Function Power States D0, D1, D2, and D3 are defined in that specification.

D0 is the maximum powered state, and D3 is the minimum powered state. Power state D3 is further categorized as D3hot or D3cold. A function that is powered off is said to be in the D3cold power state.

Power Management

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LSI 53C875A technical manual Power Management, No Download Mode, Mode a Serial Eeprom Data Format, Byte Name Description