controller installed on them (and therefore the same Vendor ID and Device ID).

If the external serial EEPROM interface is enabled (MAD[7] LOW), this register is automatically loaded at power-up from the external serial EEPROM and will contain the value downloaded from the serial EEPROM or a value of 0x0000 if the download fails.

If the external serial EEPROM interface is disabled (MAD[7] HIGH), this register returns a value of 0x1000 (LSI Logic Vendor ID). The 16-bit value that should be stored in the external serial EEPROM for this register is the vendor’s PCI Vendor ID and must be obtained from the PCI Special Interest Group (SIG). Please see Section 2.4, “Serial EEPROM Interface,”in Chapter 2 for more information on downloading a value for this register.

Registers: 0x2E–0x2F

Subsystem ID

Read Only

15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

SID

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If MAD[7] HIGH Default

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

1

 

0

0

0

 

0

 

0

0

0

0

0

0

0

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If MAD[7] LOW See Description Default

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

x

x

x

x

x

x

x

x

 

x

x

x

x

x

x

x

 

x

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SID

 

 

Subsystem ID

 

 

 

 

 

 

 

 

[15:0]

 

 

 

This 16-bit register is used to uniquely identify the add-in

 

 

 

board or subsystem where this PCI device resides. It

 

 

 

 

provides a mechanism for an add-in card vendor to

 

distinguish its cards from one another even if the cards have the same PCI controller installed on them (and therefore the same Vendor ID and Device ID).

If the external serial EEPROM interface is enabled (MAD[7] is LOW), this register is automatically loaded at power-up from the external serial EEPROM and will contain the value downloaded from the serial EEPROM or a value of 0x0000 if the download fails.

If the external serial EEPROM is disabled (MAD[7] pulled HIGH), the register returns a value of 0x1000. The 16-bit

PCI Configuration Registers

4-11

Page 103
Image 103
LSI 53C875A technical manual Registers 0x2E-0x2F, Subsystem ID Read Only, Sid, Subsystem ID 150