Dan Matthews <dmatthew@primenet.com> wrote:

> I hate to correct you when you are 99.9% right, but...
>
> In the PIC16CXX architecture EVERY instruction that accesses a
> register performs a read first, for the exact reason mentioned,
> simplification of design.
>
> In this case, a MOVWF to PORTB during what would be a change on
> PORTB interrupt will in fact clear the interrupt condition.

Thanks, Dan...  My message to John Payson was just the singlw word,
"no", so I guess the portion that was "99.9% right" was the
list's mail address, his quoted question, and my signature.

It was bad enough when only instructions that performed an EXPLICIT
read or read-modify-write kept the interrupt from happening... This
new information makes the change-on-portB interrupt almost
COMPLETELY worthless.  Does Microchip see this as a bug and plan to
correct it in future revs of the chip?

-Andy


Andrew Warren - fastfwd@ix.netcom.com
Fast Forward Engineering, Vista, California