>In my case, the interrupt is from INT0 or INT1, depending
>on the IR frequency. On each interrupt, I capture the 16
>bit value of TMR3, then reset the timer. I also reverse
>the edge detect for the associated input so I can watch
>it coming and going.

Hmm, I am just trying to do this on a 16F630, and am going to be pushing the
minimum width I can measure. However in the process I have come up with an
ingenious scheme (even if I do say so myself) to detect both rising and
falling edges without needing to change an edge setting.

The comparator will detect both edges in a similar manner to the interrupt
on port B change feature, but the clearing of the interrupt is independent
of the port read. This does away with the missed interrupt possibility of
the port b interrupt on change. The CMCON register has the current state of
the output of the comparator as one bit, and the interrupt flag and enable
as other bits. Reading port A does not clear this, you need to read CMCON to
clear the interrupt.

Luckily I need only one input like this. If you needed more, then you would
need more comparators with separate CMCON registers for each one :)

Now I just wish I had a PLL to up the internal 4MHz to 16MHz (or even 8MHz
would do). Please Mr Microchip.

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