RE: PCI-X IP Core

["Ingraham, Andrew" <Andrew.Ingraham@compaq.com>]

For plug-in cards, PCI-X cards have two capability levels.  One can be used
up to 66 MHz, the other can run up to 133 MHz.  The PCIXCAP pin is used to
indicate this capability.

PCI-X systems, when in PCI-X mode, might use any clock frequency from 50 to
133 MHz (or 50 to 66.7 MHz if PCIXCAP indicates a card is 66 MHz max).

PCI-X systems and cards are compatible with 33 MHz PCI cards and systems,
respectively.

Andy