> The traditional way would be to arrange the 16 as a 4 x 4 and use IOC
> (Interrupt-On-Change). If the PIC is inactive, the buttons will not be
> being scanned so pull-ups (internal are available) on the columns (PortB
> <4:7> ) and lows on the 4 row drive pins. On interrupt/wake-up, you'd
> know only which column caused the IOC, so scan to get the row
>

I've used this method for an LED matrix. I don't know why I didn't
think of it here. I'll prototype something out on a breadboard.

If I understand correctly, the 4 IOC pins (columns) would be pulled up
high and the 4 row pins would be driven low. When a button is pressed,
an IOC is triggered and a timer would delay Xms as a debounce, then
one would have to drive each of the row pins high one at a time to see
what row was pressed.

Thanks,
Scott
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