I've got a bit lost now but wasn't part of the original problem that the =
seperate ADC channels were being "mixed up" and I believed this to be =
caused by the >10K input impendance which fails to meet the required pin =
leak-age specification and thus the pins leak?


See note 3 under A/D Acquisition Requirements on the 16F877 datasheet.
QUOTE: "The maximum recommended impedance for analog sources is 10K
This is required to meet the pin leak-age specification."


Surely no matter how much aquisition time you allow once you've got =
leakage your stuck!
Isn't the solution to simply reduce the input impedance?

I understand the S/H idea but why do you think the problem has got =
nothing to do with leakage?
How else do you explain the interaction BETWEEN channels? Or is it =
because all channels use the same S/H circuitry or something?

Regards
Pete



> >Perhaps I'm not understanding something here, but how does=20
> the cap help
> >with the leakage current? Isn't their always leakage current=20
> on the pin,
> >regardless of whether you are sampling or not?
>=20
> Leakage current is not the primary error source here.  The=20
> S/H capacitor

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