I'm using a 16C74A with two analog inputs. ADCON1 is set 04h, so I
actually have three analog inputs. Is it OK to use the extra analog pin as
an output, as long as I set TRISA accordingly? I recall this is the case,
and looking at the block diagram of the innards of the chip it looks like
that's OK to do.

While looking for the answer to this in AN546, I noticed something
unusual. On page 4 it says(remember this document relates to a 16C71) "If
only one A/D channel is required, program ADCON1 to 03h. This configures
the A/D pins as digital I/O"

That says to me that the input buffer is enabled and what they are not
saying is that the input buffer is going to make the chip draw a little
extra current when the pin is near 1.2 volts, or whatever the transition
point is. Correct?


Thanks,

Bob