82870P2P64H2 Datasheet, PDF (76/217 Pages) –

Register Description
R
3.3.1.15
MCNF—Miscellaneous Configuration Register (Device 31)
Offset:
42–43h
Default Value: 00x3h
Attribute:
Size:
R/W, R/WO, RO
8 bits
This register contains various miscellaneous information about the hot plug controller’s operation.
Bits
Description
15
Change Device ID (CDID)—R/WO. Not implemented. Bit is read/write for software compatibility.
Default = 0
Inhibit Hot Plug (IHP)—R/WO. Default = 0
14
1 = Prevents the hot plug memory map from being accessed. In this mode, reads to memory
registers will always return 0 and writes will have no effect.
Power Fault Enable (PFE)—R/W.
0 = Disable (Default)
1 = Enable. This bit must be set to enable SERR# on power-fault generation as well as scanning
13
power-fault latches. This bit is also mapped in the MCNF Register in memory space offset
02h, bit 10. In 2-slot or 1-slot parallel modes, the Intel® P64H2 will asynchronously
disconnect a slot's bus, clock, power, and assert the slot's PCIRST#, when the slot's power
fault signal is asserted. In any serial mode, logic must exist on the motherboard to perform
these asynchronous disconnects. Clearing this bit will also clear the internal power-fault
latches.
Auto Power-Down Disable Lock Enable (APDL)—R/WO.
0 = Disable (default)
12
1 = Enable. The auto-power-down disable bit of the hot plug miscellaneous register in memory
space becomes unchangeable and read only. This bit is write-once and cannot be changed
until RSTIN# assertion.
11:8 Reserved
PCI Configuration Space Access Enable (PCFE)—R/W.
0 = Disable (Default)
7
1 = Enable. When set, this bit enables configuration space access to memory space registers
using an index register and 32-bit data access port, located at configuration offsets 50h and
54h, respectively.
6
Dummy Cycle Enable (DCE)—R/W. Not implemented. This bit has no functionality, but is
maintained as read/write for software compatibility. (Default=0)
5
PCI-X Mode (MODE)—RO. This bit indicates the mode of the PCI-X bus it is connected to. The
default is determined by the PCI-X bus mode.
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Intel^® 82870P2 P64H2 Datasheet