Don,
I have been experimenting with both the prescaler (divide by 16) and skipping it. When I use an Agilent frequency generator for testing, the count only jitters by 1 count with either approach, the measurement is very stable under this test situation with both approaches. Now that I have the PIC code working, I am now experimenting with my actual application to see which is the better method.
When measuring the period of 200 cycles of a 4 kHz signal, the frequency resolution is great, 1 count corresponds to 0.016 Hz at 4 KHz and the measurement time is 50 msec. The PIC counters are great once you understand how to set them up.
I output the count data via RS-232 to a PC.
Terry