Compaq iPAQ Internet Device 4.3.2 AGP CONFIGURATION

Technical Reference Guide
Compaq iPAQ Family of Internet Devices
First Edition - March 2000
4-11
4.3.2 AGP CONFIGURATION
AGP bus operations require the configuration of certain parameters involving system memory
access by the AGP graph ics adapter. Th e AGP bus interface is confi gured as a PCI device
integrated within the north bridge (MCH, device 1) component. The AGP function is, from the
PCI bus perspective, treated essentially as a PCI/PCI bridge and configured through PCI
configuration registers (Table 4-4). Configuration is accomplished by BIOS during POST.
NOTE: Configuration of the AGP bus interface involves functions 0 and 1 of the
MCH. Function 0 registers (listed in Table 3-4) include functions that affect basic
control (GART) of the AGP.
Table 4-4. PCI/AGP Bridge Configuration Registers (MCH, Function 1)
Table 4-4.
PCI/AGP Bridge Function Configuration Register s
(GMCH, Function 1)
PCI Config.
Addr. Register
Reset
Value
PCI Config.
Addr. Register
Reset
Value
00, 01h Vender ID 8086h 1Bh Sec. Master Lat ency Timer 00h
02, 03h Device ID 7191h 1Ch I/O Base Address F0h
04, 05h Command 0000h 1D h I/O Limit Address 00h
06, 07h Status 0220h 1E, 1Fh Sec. PCI/PCI Status 02A0h
08h Revis ion ID 00h 20, 21h Memory Base Address FFF0h
0A, 0Bh Class C ode 0406h 22, 23h Memory Limit Address 0000h
0Eh Header Type 01h 24, 25h Prefetch Mem. Base Addr. FFF0h
18h P rimary Bus Number 00h 26, 27h Prefetch Mem. Limit Addr. 0000h
19h S econdary Bus Number 00h 3Eh PCI/PCI Bridge Control 80h
1Ah Subordinate Bus Number 00h 3F-FFh Reserv ed 00h
NOTE:
Assume unmarked locations/gaps as reser ved. Refer to Intel documentation for detailed
register descriptions.
The AGP graphics adapter (actually its resident controller) is configured as a standard PCI
device.