VT8601 Via, VT8601 Datasheet - Page 63

• Manufacturer Part Number: VT8601
• Description: Slot-1 / Socket-370 PCI North Bridge
• Manufacturer: Via

Offset 8 - Revision ID ......................................................... RO
Offset 9 - Programming Interface ..................................... RO
Offset A - Sub Class Code .................................................. RO
Offset B - Base Class Code ................................................ RO
Offset 13-10 - Graphics Memory Base 0 ......................... RW
Offset 17-14 - Graphics Memory Base 1 ......................... RW
Offset 1B-18 - Graphics Memory Base 2 ......................... RW
Offset 2D-2C – Subsystem Vendor ID ............................. RW
Offset 2F-2E - Subsystem ID ............................................ RW
Offset 33-30 –Graphics ROM Base.................................. RW
Revision 1.3 September 8, 1999
31-0 Graphics Memory Base 0 .........default = E000 0000
31-0 Graphics Memory Base 0 .........default = E080 0000
31-0 Graphics Memory Base 0 .........default = E040 0000
15-0 Subsystem Vendor ID ............................ default = 00
15-0 Subsystem ID .......................................... default = 00
31-0 Graphics ROM Base ................. default = 0000 0001
8-0
7-0
7-0
7-0
7HFKQRORJLHV ,QF
VT8601 Graphics Controller Revision Code
Interface Identifier........................... always reads 00
Sub Class Code................................. always reads 00
Base Class Code
Reads 03 to indicate Graphics Controller
Defines an 8MB space for display memory
Defines a 128KB space for memory mapped I/O
Defines an 8MB space for off-screen video overlay
:H &
:H &R R QQHFW
QQHFW
-57
Offset 3C – Interrupt Line ............................................... RW
Offset 3D – Interrupt Pin .................................................. RO
Interrupts
There are several interrupt sources and their corresponding
controls in the ProMedia as shown in the following table:
1) Write 0 to clear.
2) Selected by CR9E[7:6]
3) Video capture logic can generate an interrupt which is
4) The GE interrupt is similar to the capture interrupt.
5) The VGA interrupt is similar to the capture interrupt except
7-0
7-0
selected from one of four sources determined by
CR9E.[7:6]. This interrupt is enabled by CR9B[7]. To
clear this bit write 0 to CR9B[6]. Whether an interrupt is
generated can be determined from CR9B[4].
that there is no status bit.
Device 0 Bus 1 Header Registers - Graphics Accelerator
Capture Even Field
Capture Odd Field
Capture VSYNC
Table 7. Interrupt Sources and Controls
Capture Blank
Interrupt Line ...................................... default = 0Bh
Interrupt Pin....................always reads 01h (INTA#)
Capture
Source
VGA
GE
4
5
3
VT8601 Apollo ProMedia
CR9B[7] CR9B[6]
CR11[5] CR11[4]
2122[7]
Mask
2
2
2
2
2122[7]
Clear
1
CR9B[4]
2120[4]
Status