Avago Technologies LSI53C1010R - Manual (Page 131)

PCI Configuration Registers 4-13
Version 2.2 Copyright © 2000–2003 by LSI Logic Corporation. All rights reserved.
Registers: 0x2E–0x2F
Subsystem ID (SID)
Read Only
SID Subsystem ID [15:0]
This 16-bit register uniquely identifies 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 contains
the value downloaded from the serial EEPROM or, if the
download fails, a value of 0x0000.
If the external serial EEPROM is disabled (MAD[7] pulled
HIGH), the register returns a value of 0x1000. The 16-bit
value stored in the external serial EEPROM is
vendor-specific. Refer to
Section 2.4, “Serial EEPROM Interface,” for details on
downloading a value for this register.
15 0
SID
If MAD[7] is HIGH
0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0
If MAD[7] is LOW
x x x x x x x x x x x x x x x x