Output drive High or Low depending on what they are attached to. I just did
a project where we were using the pin as an input to look for a slow
transition (analog ramp) and the power consumption was much higher when the
port was an input. I set it to output for lower power and switched to input
to test then back to output to reduce power.


At 12:24 PM 6/11/99 -0700, you wrote:
>Greetings All:
>Today's Question
>What is the best way to treat unused pins on a PIC for absolutely lowest
>possible power consumption? (and the theory behind your choice please).
>
>Options are:    output, drive hi, no termination
>                output, drive lo, no termination
>                input with pullup
>                input with pulldown
>                input floating (not really an option--pin will oscillate
sometimes)
>
>Some thoughts from my end:
>1. Inputs require a pull-up or -down resistor, possibly in the megohm
>range, but still some current flow, plus an extra part.
>2. Outputs don't require external parts, but with big ground planes and
>potential board leakage, driving low might be the best.  However, most of
>the programmers I have used tend to drive the pins hi.
>
>So What is the consensus?
>kelly
>****************************************************************************
>********
>All legitimate attachments to this email will be clearly identified in the
>text.
>William K. Borsum, P.E.
>OEM Dataloggers and Instrumentation Systems
><borsum@dascor.com> & <www.dascor.com>
>
>
Larry G. Nelson Sr.
mailto:L.Nelson@ieee.org
http://www.ultranet.com/~nr