
82815 GMCH
R
104
Datasheet
3.6.3.
PCICMD2—PCI Command Register (Device 2)
Address Offset:
Default:
Access:
Size:
04h
05h
0004h
Read-Only, Read/Write
16 bits
This 16-bit register provides basic control over the chipset’s ability to respond to PCI cycles. The
PCICMD Register in the GMCH disables PCI compliant master accesses to main memory.
15
10
9
8
Reserved (0)
FB2B
(Not Impl)
SERR En
(Not Impl)
7
6
5
4
3
2
1
0
Addr/Data
Stepping
(Not Impl)
Parity
Error En
(Not Impl)
VGA Pal
Sn
(Not Impl)
Mem WR
& Inval En
(Not Impl)
Special
Cycle En
(Not Impl)
Bus
Master En
(Enabled)
Mem Acc
En
I/O Acc En
Bits
Description
15:10
Reserved.
9
Fast Back-to-Back (FB2B)
RO.
(Not Implemented). Hardwired to 0.
8
SERR# Enable (SERRE)
RO.
(Not Implemented). Hardwired to 0.
7
Address/Data Stepping
RO.
(Not Implemented). Hardwired to 0.
6
Parity Error Enable (PERRE)
the category of devices that does not corrupt programs or data in system memory or hard drives, the
GMCH ignores any parity error that it detects and continues with normal operation.
RO.
(Not Implemented). Hardwired to 0. Since the GMCH belongs to
5
Video Palette Snooping (VPS)
RO.
Hardwired to 0. Disables snooping.
4
Memory Write and Invalidate Enable (MWIE)
memory write and invalidate commands.
RO.
Hardwired to 0. GMCH does not support
3
Special Cycle Enable (SCE)
RO.
Hardwired to 0. GMCH ignores Special cycles.
2
Bus Master Enable (BME)
master.
RO.
Hardwired to 1 to enable GMCH to function as a PCI compliant
1
Memory Access Enable (MAE)
accesses.
R/W.
This bit controls the GMCH’s response to memory space
0 = Disable (default).
1 = Enable.
0
I/O Access Enable (IOAE)
R/W.
This bit controls the GMCH’s response to I/O space accesses.
0 = Disable (default).
1 = Enable.