[Coco] overdrive ...
kevdig at hypersurf.com
Tue Apr 26 00:16:04 EDT 2005
KnudsenMJ at aol.com wrote:
> As a retired hardware designer, I agree that whatever scheme is used between
> the two CPUs, it will work better if the clocks are synchronized, so one is
> an integer multiple of the other.
> Otherwise, there will always be a "gray area" where some flip-flop is being
> set by one side just as it is read by the other, and strange things will
> happen now and then.
> Also, synchronizing the clocks means that all noise and cross-talk events
> will be repeatable, meaning you have a chance at debugging them.
> So your 68K sidecar should pick up the Coco's E/Q clocks and phase-lock to
> (Running *almost exactly* the same frequency, so the two clocks "beat"
> slowly, is guaranteed to stir up troubles -- so phase-lock 'em).
> And of course, with the 68K running at a harmonic of the NTSC frequency, you
> have the ability to run video hardware off the 68K side, if you ever want
> fast graphics.
> --Mike K.
A retired HW engineer huh. So acn you give me some pointers on how to
do this PLL thing. Can you point me to an example? How much of a
complication will the "double speed poke" be?
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