Chapter 4 System Support
Compaq Deskpro Personal Computers
Third Edition – April 2001
4-8
4.2.7 PCI CONFIGURATION
PCI bus operations require the configuration of certain parameters such as PCI IRQ routing, DMA
channel configuration, RTC control, port decode ranges, and power management options. These
parameters are handled by the LPC I/F bridge function (PCI function #0, device 31) of the ICH2
component and configured through the PCI configuration space registers listed in Table 4-4.
Configuration is provided by BIOS at power-up but re-configurable by software.
Table 4-4. LPC Bridge Configuration Registers (ICH2, Function 0)
Table 4-4.
LPC Bridge Configuration Registers 
(ICH2, Function 0, Device 31)
PCI 
Config. 
Addr.  
 
 
Register 
 
Reset 
Value 
PCI 
Config. 
Addr. 
 
 
Register 
 
Reset 
Value 
00, 01h  Vendor ID  8086h  8Ah  Device 31 Error Status  00h 
02, 03h  Device ID  2440h  90, 91h  PCI DMA Configuration  0000h 
04, 05h  Command  000Fh  A0-CFh  Power Management   
06, 07h  Status  0280h  D0-D3h  General Control  0’s 
08h Revision ID  00h D4-D7h General Status  F00h 
0A-0Bh  Class Code  0106h  D8h  RTC Configuration  00h 
0Eh  Header Type  80h  E0h  LPC COM Port Dec. Range  00h 
40-43h  ACPI Base Address  1  E1h  LPC FDD & LPT Dec. Rge  00h 
44h  ACPI Control  00h  E2h  LPC Audio Dec. Range  80h 
4E, 4Fh  BIOS Control  0000h  E3h  FWH Decode Enable  FFh 
54h  TCO Control  00h  E4, E5h  LPC I/F Decode Range 1  0000h 
58-5Bh  GPIO Base Address  1  E6, E7h  LPC I/F Enables  0000h 
5Ch  GPIO Control  00h  E8-EBh  FWH Select 1  00112233 
60-63h  INTA-D Routing Cntrl.  80h [1]  EC, EDh  LPC I/F Decode Range 2  0000h 
64h  Serial IRQ Control  10h  EE, EFh  FWH Select 2  5678h 
68-6B  INTE-F Routing Cntrl.  80h [1]  F0h  FWH Decode Enable 2  0Fh 
88h  Dev. 31 Error Config.  00h  F2h  Function Disable Register  00h 
 
NOTE:  
[1] Value for each byte. 
Assume unmarked locations/gaps as reserved.