Sat Dec 25 03:06:52 EST 2010

PIC comparator output

For the current-source controlled sawtooth generator I need a
comparator on the PIC with output to the discharge transistor.

The 18F1220 doesn't have on-board comparators.  It's not a disaster to
use an off-board one as there might be some other uses for a quad
comparator chip, but let's look at the next one up: the 18F2550 has
two, both have (invertable) digital outputs C1OUT/C2OUT.