Mike Keitz wrote:
>
> A "dummy" ISR consisting of just RETFIE won't clear any interrupt request
> flags.  If an enabled interrupt flag does become set, the PIC will start
> processing interrupts constantly and the main program will stop.
>
> It would be better to use a RETURN instead.  The PIC's interrupt logic
> clears the GIE flag after every interrupt, then ordinarily the RETFIE
> will re-set it and allow more interrupts.  But in this case you don't
> want more interrupts.  A RETURN will leave GIE cleared so more should
> occur after the first spurious one.  In order to be more sure, you could
> make the "dummy" ISR a little longer and have it clear all the IE flags
> before returning.

This is a good idea.  I figure that there is a typo in the second paragraph and
you meant
to say:

"A RETURN will leave GIE cleared so NO more should occur after the first spuriou
s one."
                                    ^^
Yes?

As far as commercial products (mentioned by a slew of other posters), I never me
ant my
RETFIE to be applied there!  The original poster was talking about a quick one-o
ff thingy
for a hobby project I thought.  I was suggesting that I threw in the RETFIE as b
eing
better than nothing at 0x004.  Mike's idea of RETURN sounds much better if it wi
ll clear
GIE.

Back to the Microchip CD ROM...  Thanks Mike.

Michael

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When the way of the Tao is forgotten, kindness and ethics must be taught.
Men must learn to pretend to be wise and good.  --  Lao Tzu
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