Compaq EN Series - page 56

Technical Reference Guide
Compaq Deskpro EN Series of Personal Computers
Desktop and Minitower Form Factors
Third Edition - September 1998
4-7
Not required
Table 4–4. PCI Function Configuration Acces
Table 4-4.
PCI Function Configuration Access
PCI Function Device No. Function No.
Host/PCI Bridge (82443) 0 0
PCI/AGP Bridge (82443) 0 1
PCI/ISA Bridge (82371) 20 0
IDE Interface (82371) 20 1
USB Interface (82371) 20 2
Power Management Cntlr. (82371) 20 3
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 (see Figure 4-4), of which the first 64 bytes comprise the configuration space
header.
Figure 4–4. PCI Configuration Space Map
Each PCI device is identified with a vender ID (assigned to the vender by the PCI Special Interest
Group) and a device ID (assigned by the vender). The device and vender IDs for the devices on
the system board are listed in Table 4-5.
00h
Configuration
Space
Header
Vender ID
Data required by PCI protocol
Base Address Registers and Exp. ROM Addres s
Register
Index
31
Cache Line Size
Latency Timer
Device ID Command
Status Revision IDClass Code
Header T
y
pe
BIST
Device-Specific Area
Interrupt LineInterrupt PinMin_GNTMin_Lat
24 23 16 15 8 7 0
04h
08h
0Ch
3Ch
40h
FCh