Hi !
I have not copied the full code, it's there in yur post for everyone to 
see...

Now, let me see if I understand here.
You have TMR1 interrupting each 0.5 sec.
You count those interrupts ("rollovers").
At each rollover you take a *new* A/D sample and
compare to the current "number of rollovers".

Right so far ?

Now, I think one problem is that, even if the pot is left
alone, your A/D value will "flicker" a few bits between
each A/D reading. And since you are making a new
A/D reading each time, you might "miss" the "hit".
I'd only make a new A/D reading right after the
current reading have had a match with the rollover
counter.

Have you made a quick test-case to test that you actualy
can read the A/D line at all ?

A few other things...

> ;       GP1 - Not used.  (Seems to be blown on this particular chip.)

Hm, are you sure that GP0 works ???

> ;       GP5 - Drives an LED on a clock tick.  Visual 
> indication that program is working.

Well, at least that the program is *running* and the *LED*
is working... :-)

One often hears that one should put as little as possible in the ISR
and do the rest in main. But in *this* case, since your main routine
doesn't do anything else then wait for the ISR to set the flag,
and there is no other interrupt sources, you could just as well
move more of the code into the ISR. That would simplify the
structure a little. I don't know if it solves your problem...

I'd make a test-case to verify if the A/D module is working at all.

Oh, I nearly forgot...
Where do you wait for the A/D conversion to finish ?
Or are you just hoping that it will be finished in the next
0.5 sec (it probably will, but I think one should check the
GO flag anyway...).

And I'll also make sure that I just a chip without any "blown" pins !
It's hard to know what else might been broke inside...

Jan-Erik.



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