> Probably NOT.
>
> Try it and see what happens to the OTHER analog inputs.  I suspect that
you
> will see that those other analog inputs get messed up pretty badly
whenever
> ANY analog pin has a high enough voltage to allow current to flow through
> the PIC's substrate.
>
> This is definitely the case with the 16c71 and 16c73 chips.  I assume that
> all Microchip parts are affected by these substrate currents.

You are absolutely right.  I have encountered exactly what you describe.  I
had several analog inputs fed thru 10K resistors to a 16F876.  The other
ends of the 10K could go as high as 8V, causeing as much as 300uA thru the
protection diodes, which was well within specs.  The chip ran fine and
didn't get damaged, but all the other analog inputs converted to bogus
values when one of them was doing this.  I actually suspect that this had
more to do with messing up the internal Vref than causing any problem due to
the protection diodes conducting.  I split the 10K into two 5K resistors
with a diode to +5V in the middle.  That fixed the problem.


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