Product specifications

VT8235 V-Link South Bridge
Revision 1.22 October 24, 2002 -45- PCI Configuration Space I/O Registers
Configuration Space I/O
Configuration space accesses for all functions use PCI
configuration mechanism 1 (see PCI specification revision 2.2
for more details). The ports respond only to double-word
accesses. Byte or word accesses will be passed on unchanged.
Port CFB-CF8 - Configuration Address .........................RW
31 Configuration Space Enable
0 Disabled................................................. default
1 Convert configuration data port writes to
configuration cycles on the PCI bus
30-24 Reserved ........................................ always reads 0
23-16 PCI Bus Number
Used to choose a specific PCI bus in the system
15-11 Device Number
Used to choose a specific device in the system
10-8 Function Number
Used to choose a specific function if the selected
device supports multiple functions
7-2 Register Number
Used to select a specific doubleword in the device’s
configuration space
1-0 Fixed ........................................ always reads 0
Port CFF-CFC - Configuration Data ..............................RW
There are 8 “functions” implemented in the VT8235 (see
Table 5 on page 21). The following sections describe the
registers and register bits of these functions.