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Chapter 4 System Support
Compaq Deskpro EN Series of Personal Computers
Desktop and Minitower Form Factors
Third Edition - September 1998
4-10
4.2.7 PCI CONFIGURATION
PCI bus operations, especially those that involve ISA bus interaction, require the configuration of
certain parameters such as PCI IRQ routing, top of memory accessible by ISA, SMI generation,
and clock throttling characteristics. These parameters are handled by the PCI/ISA bridge
function (PCI function #0) of the South Bridge component and configured through the PCI
configuration space registers listed in Table 4-6. Configuration is provided by BIOS at power-up
but re-configurable by software.
Table 4–6.
PCI/ISA Bridge Configuration Registers (82371, Function 0)
Table 4-6.
PCI/ISA Bridge Configuration Registers
(82371, Function 0)
PCI Config.
Addr. Register
Reset
Value
PCI Config.
Addr. Register
Reset
Value
00, 01h Vender ID 8086h 63h PCI Interrupt Routing 80h
02, 03h Device ID 7111h 64h Serial Interrupt Control
04, 05h Command 69h Memory Map Control 02h
06, 07h Status 6A, 6Bh SERR-/PCI Cycle Retry 00h
08h Revision ID 76, 77h DMA Enable/Ch. Routing
09-0Bh Class Code 80h A12 Mask/X-Y Base Addr. 00h
0Eh Header Type 82h USB Passive Rel. Enable 00h
4Ch DMA Aliasing Control 00h 90, 91h DMA Channel Select 00h
4E-4Fh APIC/BIOS Control 0003h 92, 93h DMA 0-3 Base PTR 00h
60h PCI Interrupt Routing 80h 94, 95h DMA 4-7 Base PTR 00h
61h PCI Interrupt Routing 80h B0-B3h GPIO/Misc. Funct. Select 00h
62h PCI Interrupt Routing 80h CBh RTC/RAM Control 21h
NOTE: Assume unmarked locations/gaps as reserved.