Ben Hencke wrote :

> 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.

and Jan-Erik Soderholm <PICLIST@mitvma.mit.edu> replied:

> The same.

Guys:

(paraphrased from something I posted 4 years ago)

It would be easy to test:  You'd just need a variable-frequency
square-wave input to PORTB, a foreground routine that does nothing
but write to PORTB in a tight loop, an ISR that toggles a PORTA pin
on every PORTB change,  and two external counters whose readouts you
can compare.

Some PICs don't miss portb-change interrupts even if the pin-state
changes during an explicit read; if you're using one of those chips,
you'll never see the problem.

If you're using one of the chips that DOES have the problem, though,
the fact that you haven't seen it in your current   project doesn't
mean that it doesn't (or won't) happen.

-Andy

=== Andrew Warren -- aiw@cypress.com
=== Principal Design Engineer
=== Cypress Semiconductor Corporation
===
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation

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