7-13
Register Descriptions
PCI SubSystemVendor ID Register
Type: R
Internal Registers Subgroup: PCI Configuration Header
Byte Address: 2Ch - 2Dh
PCI SubSystem ID Register
Type: R
Internal Registers Subgroup: PCI Configuration Header
Byte Address: 2Eh - 2Fh
PCI EXPROMCTL (Expansion ROM Control) Register
Type: R/W
Internal Registers Subgroup: PCI Configuration Header
Byte Address: 30h - 33h
The Expansion ROM Base Address register is used to define the base address,
maximum size and access enable control of an external ROM which may be used
with a PCI device. The PCI supports an external ROM/EEPROM of 256-KBytes.
When an access is made with both BASEADR0 and EXROMCTL address defined
region overlaps and EXROMEN is active, the PCI responds with a target-abort.
Table 7-19. SubSystemVendor ID Register
Bit(s)
rw
Reset
Value
Description/Function
15:0
r
9004h
SubSystemVendorID[15:0]:
The PCI SubSystem Vendor Identifier
register helps to identify the vendor of the add-in board even
though the PCI controller has been designed by another vendor
and has another Vendors ID. The default value is the Adaptec
Vendor ID number, 9004h. This value can be changed to a value
read from an external serial EEPROM if BR_A1 pin is ‘1’ when
PCI_PCIRST_
is deasserted.
Table 7-20. SubSystem ID Register
Bit(s)
rw
Reset
Value
Description/Function
15
r
0
64-bit Address Space:
For Base Address 0 register bit 2. Setting
this bit indicates 64-bit address space. Clearing the bit indicates
32-bit address space.
14:0
r
xxxxh
SubSystemID:
The PCI SubSystem Identifier register provides the
vendors of add-in cards a mechanism to distinguish their cards
from one another even though the cards may have the same PCI
device ID. This value can be changed to a value read from an
external serial EEPROM if BR_A1 pin is ‘1’ when PCI_PCIRST_ is
deasserted. Refer to Table 7-35 for the possible default values for
the SubSystem ID.
