82870P2P64H2 Datasheet, PDF (54/217 Pages) –

Register Description
R
Bits
Description
Split Completion Discarded (SCD)—R/WC.
0 = No split completion discarded.
2
1 = P64H2 discarded a split completion moving toward the secondary bus because the
requester would not accept it.
Note: Software clears this bit by writing a 1 to it.
1
133 MHz Capable (C133)—RO. Hardwired to 1; indicates that the P64H2’s secondary interface
is capable of 133 MHz operation in PCI-X mode.
0
64-bit Device (D64)—RO. Hardwired to 1; indicates the width of the secondary bus as 64-bits.
3.2.27
PX_BSTS—PCI-X Bridge Status Register (D29,31: F0)
Offset:
54–57h
Attribute:
Default Value: 000100F8h (PCI Bus A) Size:
000100E8h (PCI Bus B)
RO
32 bits
This register identifies PCI-X capabilities and current operating mode of the bridge.
Bits
Description
31:22
21
20
19
18
17
16
15:8
7:3
2:0
Reserved
Split Request Delayed (SRD). Hardwired to 0. This bit is not supported by the Intel® P64H2,
because it will never be in a position where it cannot issue a request.
Split Completion Overrun (SCO). Hardwired to 0. This bit is not set by the P64H2 because the
P64H2 never requests on the hub interface more data than it has room to receive.
Unexpected Split Completion (USC). Hardwired to 0. This does not apply to the hub interface,
which is the primary interface.
Split Completion Discarded (SCD). Hardwired to 0. This does not apply to the hub interface.
133 MHz Capable (C133). Hardwired to 0. This bit indicates that the bridge’s primary interface is
capable of 133 MHz operation in PCI-X mode.
64-bit Device (D64). Hardwired to 1. The hub interface is a 64-bit interface (in Hub Interface2.0,
it really is 128-bits). This field really does not apply to the hub interface, but is set to 1 to be safe
in case some software gets written.
Bus Number (BNUM). This field is an alias to the PBN field of the BNUM register at offset 18h.
Device Number (DNUM). This field provides read only bits for PCI-X
For PCI Bus A, this field defaults to 1Fh (device 31).
For PCI Bus B, this field defaults to 1Dh (device 29).
Function Number (FNUM). This field provides additional read only bits for PCI-X. These bits are
typically used by PCI-X diagnostic software.
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Intel^® 82870P2 P64H2 Datasheet