[Open-graphics] How we compute video clocks

[Timothy Normand Miller]

On 3/5/08, Michael Meeuwisse <mickeymeeuw at gmail.com> wrote:
>
>  On 5 Mar 2008, at 19:47, Timothy Normand Miller wrote:
>
>  > On 3/5/08, Michael Meeuwisse <mickeymeeuw at gmail.com> wrote:
>  >
>  >>> BTW, only clock on clocks.  Then use 'if' to decide whether or not
>  >>> to assign.
>  >>
>  >>
>  >> What do you mean with clock on clocks?
>  >
>  > Don't use a data signal as a clock.  Obviously, we're doing this in
>  > the clock GENERATOR, but once we have the signal generated properly,
>  > we connect it up to the clock distribution network (via a BUFG).  But
>  > in general, for "always @(posedge X)", X should only be a clock
>  > signal, not the output of some register or combinatorial logic.
>
>
> Ok, that makes sense. But then I don't know what clock to use. I
>  could introduce yet another one as incoming, but that might end up
>  being redundant.

What you want is the bridge bus clock, because this is a configuration
register, set through making writes to PCI.  I think we may call it
"bridge_clock" in the S3 top level.


-- 
Timothy Normand Miller
http://www.cse.ohio-state.edu/~millerti
Open Graphics Project