I need some advice about interfacing an infrared phototransistor to a PIC
via a single I/O pin.  What is a cheap way to do a little conditioning on
those sawtooth waves.  I am going to be implementing 1200 baud UART in
software.  And I have A/D ports available if necessary but I'd really like
to feed it to a digital port on the pic so that I can use interrupt on
change.