MCUs in question are '908JK3 vs '908JL3. The JK3 does not have PTA0-5 and PTD0-1 available whereas the JL3 does. If I were using the JL3 I would either configure unused port pins as output and let them float, or preferably, as input as tie them to ground. What though of the port lines PTA0-5 and PTD0-1 that are not available on the 20 pin package? Is it bad to have them as inputs and let them float? I think maybe it is. I have done this in the past and generally not had any obvious trouble, but now I am thinking it would be better to just make them outputs seeing I cannot physically tie them to anything. Or for that matter, are the io ports implemented on the die used in the 20 pin package?