Product specifications

VT8235 V-Link South Bridge
Revision 1.22 October 24, 2002 -61- Device 17 Function 0 Bus Control Registers
Device 17 Function 0 Registers – Bus Control and Power
Management
All registers are located in the device 17 function 0
configuration space of the VT8235. These registers are
accessed through PCI configuration mechanism #1 via I/O
address 0CF8h / 0CFCh.
PCI Configuration Space Header
Offset 1-0 - Vendor ID (1106h)......................................... RO
Offset 3-2 - Device ID (3177h) .......................................... RO
Offset 5-4 - Command.......................................................RW
15-8 Reserved ........................................ always reads 0
7 Address / Data Stepping
0 Disable
1 Enable ................................................... default
6-4 Reserved ........................................ always reads 0
3 Special Cycle Enable .......................RW, default = 0
2 Bus Master ........................................ always reads 1
1 Memory Space.................................... RO, reads as 1
0 I/O Space ........................................ RO, reads as 1
Offset 7-6 - Status...........................................................RWC
15 Detected Parity Error....................write one to clear
14 Signalled System Error...................... always reads 0
13 Signalled Master Abort .................write one to clear
12 Received Target Abort...................write one to clear
11 Signalled Target Abort..................write one to clear
10-9 DEVSEL# Timing....................fixed at 01 (medium)
8 Data Parity Detected
Reads 1 if PERR# is asserted (driven or observed) or
a bus master data parity error occurred.
7 Fast Back-to-Back Capable............... always reads 0
6-0 Reserved ........................................ always reads 0
Offset 8 - Revision ID (nnh) ..............................................RO
7-0 Revision ID
Offset 9 - Program Interface (00h)...................................RO
Offset A - Sub Class Code (01h) .......................................RO
Offset B - Class Code (06h)...............................................RO
Offset E - Header Type (80h)............................................RO
7-0 Header Type Code......... 80h (Multifunction Device)
Offset F - BIST (00h).........................................................RO
Offset 2F-2C - Subsystem ID ............................................RO
Use offset 70-73 to change the value returned.