Re: FFs for GNT and REQ

["Stefan Spaeth, tel. +49 711.821.43051, fax 45571" <S.Spaeth@alcatel.de>]

Zipper Thomas wrote:
> 
> Hi,
> 
> would I violate the PCI Spec when I add flip-flops to GNT and REQ lines of an arbiter?
> (in other words the arbiter sees the REQ signal delayed by one clock and the master requesting the bus sees the GNT signal also delayed by one clock)

I don't see a problem for REQ# (although it may not be nice to
assert request and then not take the bus). Anyway, I assume that an
arbiter would be able to cope with that situation (potentially arising
at the end of a transfer).

It is, however, certainly critical for GNT#. You may only assert FRAME# when
GNT# is
detected asserted - and this may no longer be the case one cycle later.
Therefore I don't think your idea works for GNT#.

Regards,
  Stefan

> Thnx & Ciao
> 
> Thomas

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