Unless I am losing my mind, I currently use IOC on a running 12f629 to
detect pin changes. I constantly write to GPIO using MOVWF and have no
problems.

IIRC on these chips, you can write to the port and it will not reset
the IOC internal latch values (internal latch not GPIF interupt flag
or whatever). However, BSF, BCF, ANDWF, etc are all read-modify-write
instructions that will cause a "read" and reset the IOC latches. So
you would have to use MOVWF to update your pins without messing up the
IOC.

The only time I read from GPIO is when I am in the IOC handler
routine, just before clearing the interupt flag. The flag is "sticky"
until you read from GPIO.


- Ben

On Fri, 11 Jun 2004 14:49:19 -0700, William Chops Westfield
<westfw@mac.com> wrote:
>
> On Friday, Jun 11, 2004, at 14:28 US/Pacific, Bob Blick wrote:
> >
> > Interrupt-on-change should be renamed "wake-up-on-change" because it's
> > useless on a running processor.
> >
> Oh.  Rats!  I suppose it would be OK if you have the entire port set to
> be inputs, as in a keyboard scanner?
>
> Thanks
> Bill W
>
>
>
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