If you go with the on/off idea, you might want to have the PIC track the
AC wave and turn it on/off at the zero-crossing, and doing timing based
on pulses. If you start chopping pulses in half it might end up causing
some drift (I guess it depends on how accurate you want to be).

You could also just have a fast switch and do per-pulse on/off. Same
idea, but instead of generating the pulses yourself you just chop the AC
wave.

-- 
Hector Martin (hector@marcansoft.com)
Public Key: http://www.marcansoft.com/marcan.asc

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