Re: 66 MHz Capability bit in AGP

[png@woof.net (Peter N. Glaskowsky)]

> I am facing a dilemma in how to set the PCI Config Register 66 MHz
> capability bit for an AGP compliant device. We plan to be compliant
> with the 66 MHz timing requirements of the AGP bus, but not the
> more stringent 66 MHz timing requirements of the proper PCI bus. Also,
> we intend for our chip be able to go on a PCI-33 board as well as an AGP
> board.

I'd set the bit to 1 to indicate that your part is capable of 66-MHz
operation. When it's installed on a conventional PCI card, ground the M66EN
pin. This will prevent the card from operating at 66 MHz. When it's
installed on an AGP card, you can let M66EN float (if this is how the AGP
connector works; I don't know). In a motherboard application, you can
always make sure your part works, of course.

.                    png

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