VT8601 Via, VT8601 Datasheet - Page 39

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

Miscellaneous I/O
One I/O port is defined in the ProMedia: Port 22.
Port 22 – PCI /AGP Arbiter Disable ............................... RW
This port can be enabled for read/write access by setting bit-7
of Device 0 Configuration Register 78.
Revision 1.3 September 8, 1999
7-2
1
0
7HFKQRORJLHV ,QF
Reserved
AGP Arbiter Disable
PCI Arbiter Disable
:H &
:H &R R QQHFW
0
1
0
1
QQHFW
Respond to GREQ# signal .....................default
Do not respond to GREQ# signal
Respond to all REQ# signals..................default
Do not respond to any REQ# signals, including
PREQ#
........................................ always reads 0
-33-
Configuration Space I/O
All registers in the ProMedia (listed above) are addressed via
the following configuration mechanism:
Mechanism #1
These ports respond only to double-word accesses. Byte or
word accesses will be passed on unchanged.
Port CFB-CF8 - Configuration Address ......................... RW
Port CFF-CFC - Configuration Data .............................. RW
Refer to PCI Bus Specification Version 2.2 for further details
on operation of the above configuration registers.
30-24 Reserved
23-16 PCI Bus Number
15-11 Device Number
10-8 Function Number
7-2
1-0
31
Configuration Space Enable
Used to choose a specific PCI bus in the system
Used to choose a specific device in the system
(devices 0 and 1 are defined)
Used to choose a specific function if the selected
device supports multiple functions (only function 0 is
defined).
Register Number (also called the "Offset")
Used to select a specific DWORD in the
configuration space
Fixed
0
1
Disabled................................................. default
Convert configuration data port writes to
configuration cycles on the PCI bus
........................................always reads 0
........................................always reads 0
VT8601 Apollo ProMedia
Register Summary Tables