Matrix user forums

Can one drive an adc pin from the output of an opamp or does one need to put a resistance/filter between them for proper operation?

I think it's always a good idea to provide some kind of protection when connecting to a PIC i/o line, mainly because the program you write may accidentally set the pin as an output. If it gets set to output low but the external circuitry is forcing it high, there is a good chance that the micro itself will get permanently damaged.

You must also make sure the voltage does not go beyond the power rails (0V and probably 5V).

I hope this helps.