> Is the PIC fast enough to be useable as a character generator to overlay
> text/graphics on NTSC video?  About 10 chars/line is all I need; nothing
> fancy.  (I want to overlay date/time on a camera feed.)

You can probably manage this.  You'll need analog hardware for sync-detect
and DC-restoration.  For the character generation itself doing date/time
shouldn't be a problem.  The biggest issue is that the transmission of dots
to the screen must be done with an RC oscillator; if your PIC is driving the
pixels directly, then it would have an RC oscillator and not be very good
for timekeeping.  I think my recommended approach would be to feed port A
and the lower 4 bits of port B into an 8-input mux and use the top 3 bits of
4-bit synchronous counter [driven by an RC oscillator] to select.  The LSB
of the counter can be used to latch the output of the mux, and the MSB (in
addition to serving as bit 2 of the selector) would be sent to the PIC.  Then
when port A is being output, port B can be updated; then when B is output, A
can be updated; etc.

BTW, a sync pulse should (in hardware) reset both the RC oscillator and
counter.  The PIC can keep track of vertical timing.