I think it is an absolutely brilliant idea Dan, dual
processing in a very clever form. It also goves the option of
having different code in each pic for further control of
energy use vs performance.
The ram/eeprom issue may be a problem, as the two PIC would
not have the same memory, but for some apps this might not
matter, and in other apps an external eeprom etc would be
useful anyway, they could share it.
The only bad point? Maybe the price of two PICs? Maybe you could
"push me pull me" with a 12xx pic and a f877 or something, with
them sharing some essential pins like the input/buttons,
but only the big pic having the output power driver stuff.
That might work cool too. "big brain small brain" stuff. :o)
-Roman




Dan Michaels wrote:
>
> In the wild flurry to be the first to sail a PIC around
> the world, my poor little pushmepullyou idea was overlooked.
>
> This is actually a serious inquiry. Any comments about having
> dual-clock operation by putting 2 PICs exactly in parallel,
> with each running off a different clock - say 20mhz vs 32khz ???
>
> See below:
> =========

>
> Hmmm, this is just the latest weird thought from the weird
> land somewhere over the rainbow - ie, Boulder, where Dorothy
> landed after leaving Kansas:
>
> People keep wanting to run a PIC off 2 different clocks. So
> how's about 2 PICs, wired with all pins exactly connected in
> parallel, except /MCLR and OSC. One goes 20 Mhz, the other
> 32Khz. When one is going, the other is held in reset /MCLR=low
> [and all pins float]. Exact interplay details to be worked
> out. To be called the "2DoNothing" or "pushmepullyou" circuit,
> or something or other.
>
> So how much mA does a PIC draw when held in reset, anyways?
> Powerdown current = 1.5 uA ??????
>
> - danM
>
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