ULPWU & PLVD on 12F635 & 16F684

[Bruce]

question
do you see a way to distinguish this ULPWU interrupt from some other pin that may have
caused wake up from SLEEP ? i don't

If you had int on change enabled for more pins, you would need to read the port & look for
a change immediately on wake up. Other interrupts would set the flag bit associated with
that interrupt. I don't see any specific flag bit for ULPWU alone.

also
in your example code PROBE is for your scope and not directly related to the ULPWU pin, when
you TOGGLE PROBE

Yes. I just used this pin for the scope to see the timing when using different cap and resistor
values.

your comment says 'clear mismatch register' does this mean that writing to any pin will clear
the mismatch ?

A normal wake up on change requires you to read or write to the port to clear the
mismatch condition. Then clear the interrupt flag bit.

i thought there was a mismatch bit for each pin

The only pin that affects wake up on change is the one that has this feature enabled, and
is an input. There aren't any mismatch bits, but there are individual interrupt on change
enable and disable bits in IOCA.

You can remove the TOGGLE PROBE & INTCON.0 = 0 after. This gets taken care of before
the sleep instruction.