Some recommend setting the micro's unused pins as inputs to lower power drain.
However, these are CMOS devices, and leaving an input to blow in the wind causes
it to oscillate erratically.  These oscillations use current as transistors in
the chain from the input go from high to low.

To keep inputs from oscillating, it is recommended to tie them high or low
through a large resister (10k-100k).  The current draw on the pin through the
resister is incredibly low.

I don't know what the case is between making a pin an input or output, and which
draws more power, but I believe I've read microchip's recommendation in their
various data sheets, so it shouldn't be too difficult to find.

-Adam

Steven Rightnar wrote:
>
> I have seen it everywhere (pull all unused output lines to 5 volts). OK what
> if you dont do this? I have one curcuit that seemed to work fine and I did
> not pull the outputs up.
>
> Thanks,
>
> Steve