beautypg.com

Subsystem id, Registers: 0x2e–0x2f – Avago Technologies LSI53C896 User Manual

Page 124

background image

4-12

Registers

Version 3.3

Copyright © 1998–2003 by LSI Logic Corporation. All rights reserved.

Registers: 0x2E–0x2F

Subsystem ID
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 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
value that should be 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