Signal Description
Accesses to the internal Intel® 6700PXH 64-bit PCI Hub configuration registers, which includes
the bridge configuration registers and the CSR memory registers, follow no ordering relationship
with respect to transactions moving to and from the PCI and PCI Express* buses. Outbound
memory/configuration transactions to the internal register space could complete out of order with
respect to transactions pending in the outbound queues towards the PCI bus. Software must be
aware that any semaphore mechanism implemented through the internal Intel® 6700PXH 64-bit
PCI Hub register space requires a dummy read to PCI or PCI Express* space to push the writes that
could be pending in the Intel® 6700PXH 64-bit PCI Hub queues in either direction. The ordering
tables in the next two sections do not consider these transactions.
2.14.1.1
Inbound Transaction Ordering
Table 2-27 lists the combined set of ordering rules in the inbound path of the Intel® 6700PXH
64-bit PCI Hub.
Table 2-27. Inbound Transaction Ordering
Delayed/Split
Read
Completion
Delayed/Split
Write
Completion
Posted
Write
Delayed/Split
Read Request
Row pass Column
Posted Write
No
No
Yes
Yes
No
No
No
Delayed/Split Read
Request
Yes
Delayed/SplitIO Write
Request
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
No
NO
No
Delayed/Split Read
Completion
Delayed/Split
Write Completion
2.14.1.2
Outbound Transaction Ordering
Table 2-28 lists the combined set of ordering rules in the outbound path of the Intel® 6700PXH
64-bit PCI Hub.
Table 2-28. Outbound Transaction Ordering
Delayed
(Split) Read
Request
Delayed (Split)
Read
Completion
Delayed (Split)
Write
Completion
Posted
Write
Row pass Column
Posted Write
No
No
Yes
Yes
Yes
Yes
Yes
Delayed/Split Read
Request
Yes1
Delayed/Split
Write Request
No
Yes
Yes
Yes
Delayed/SplitIO Write
Completion
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Delayed/Split
Read Completion
NOTE: The Intel® 6700PXH 64-bit PCI Hub supports two outbound completion required requests per PCI
segment. Outbound delayed/split read requests can pass each other when issued on the PCI bus.
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Intel® 6700PXH 64-bit PCI Hub Datasheet
INTEL [ INTEL ]
