I'm not sure, but this may already have come up on the list.  If so
please direct me to the archive and I will look there.  However, any
ideas would be great full.  

What I will be having to do is synchronize to the incoming AC.  To do
this I will have to detect RMS voltage, Detect the zero crossing,
generate the sine wave reference and then synchronize to the line.  

Any ideas on detecting the zero crossing?À  I want to do it software not
hardware.  I've already done it in hardware using 2 pins on the micro.
I want to do it with 1 pin now.

John Bellini
Product Development, Firmware Technologist