LSI LSI53C895A, Technical Manual

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PCI Configuration Registers 4-11
vendor’s cards, 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] 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.
In addition, if the Subsystem ID Access register
(0x48–0x4B) is enabled and unlocked then this register
will contain the value that is written into the Subsystem
ID Access register. Please see
Section 2.5, “Alternative
SSVID/SSID Loading Mechanism,” in Chapter 2 for
additional information.
Registers: 0x2E–0x2F
Subsystem ID
Read Only
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).
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