Sun May 25 14:24:24 EDT 2014


Might do input capture manually from the comparator change interrupt.
Basically, read TMR0L then TMR0H

   Section 11: TMR0 module:

   TMR0H is updated with the contents of the high byte of Timer0
   during a read of TMR0L.

So to get an update:
- read timer
- push
-  subtract previous
-  shift / multiply
-  add to accumulator
- pop
- store previous

Probably best to keep the timer rolling.

If the input capture is not used for anything, this can actually be
split into a top and bottom half, with top half just initiating the
capture and the bottom half performing the update.