
Technical Reference Guide
Compaq Deskpro EX Series of Personal Computers
First Edition - August 2000
4-5
Not required
The register index (CF8h, bits <7..2>) identifies the 32-bit location within the configuration space
of the PCI device to be accessed. All PCI devices can contain up to 256 bytes of configuration data
(Figure 4-3), of which the first 64 bytes comprise the configuration space header.
Figure 4-3.
PCI Configuration Space Mapping
Each PCI device is identified with a vendor ID (assigned to the vendor by the PCI Special Interest
Group) and a device ID (assigned by the vendor). The device and vendor IDs for the devices on
the system board are listed in Table 4-2.
Table 4-2.
System Board
PCI Device Identification
Table 4-2.
System Board PCI Device Identification
PCI Device
Vendor ID
Device ID
82815 GMCH:
Memory Controller
AGP Bridge
I740 Graphics Controller
8086h
8086h
8086h
1130h
1131h
1132h
82801AA ICH:
PCI Bridge
LPC Bridge
EIDE Controller
USB I/F
SMBus Controller
AC97 Audio Controller
AC97 Modem Controller
8086h
8086h
8086h
8086h
8086h
8086h
8086h
2418h
2410h
2411h
2412h
2413h
2415h
2416h
Data required by PCI protocol
Configuration
Space
Header
PCI Configuration Space Type 1
Class Code
Command
31
24 23
16 15
8
7
0
Revision ID
Vendor ID
Status
Device ID
Expansion ROM Base Address
Reserved
Prefetchable Limit Upper 32 Bits
Prefetch. Mem. Limit
Prefetch. Mem. Base
Prefetchable Base Upper 32 Bits
Device-Specific Area
Line Size
Lat. Timer
Int. Line
Int. Pin
BIST
Hdr. Type
Pri. Bus #
Sec. Bus #
Sub. Bus #
2
nd
00h
Register
Index
04h
08h
0Ch
2Ch
30h
FCh
18h
28h
3Ch
38h
34h
40h
Bridge Control
I/O Base Upper 16 Bits
I/O Limit Upper 16 Bits
24h
20h
Memory Base
Memory Limit
I/O Base
I/O Limit
Secondary Status
1Ch
10h
Base Address Registers
00h
Register
Index
04h
08h
0Ch
2Ch
30h
FCh
10h
28h
3Ch
38h
34h
40h
Command
31
24 23
16 15
8
7
0
Revision ID
Vendor ID
Status
Device ID
Reserved
Reserved
Expansion ROM Base Address
Subsystem Vendor ID
Subsystem ID
Card Bus CIS Pointer
Device-Specific Area
Line Size
Lat. Timer
Int. Line
Int. Pin
Min. GNT
Min. Lat.
BIST
Hdr. Type
Class Code
Base Address Registers
PCI Configuration Space Type 0