Summary: what preprocessing is needed for analog signals into 16f877?

I've reviewed quite a few designs involving analog to digital converters
and one trend is to include a unity gain buffer before the A/D input.

This seems a lot of trouble.  Can I do without it?  I see from the PDF
file for the 16f877 that impedance greater than 10k is not good.  For
my quick hack, which is monitoring the voltage on a 12v battery, is it
practical to just whack the voltage in via a dividing network, with a
series resistance to limit the current in case of excessive voltage?

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James Cameron   mailto:quozl@us.netrek.org   http://quozl.us.netrek.org/