Code is fine.  I found the problem.  There was an IC chip further down the
line that was fried.  So, when A0 went high it was feeding voltage back
through the IC chip to D0.

Thanks for replying though.

Jim

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Jan-Erik Soderholm
Sent: Tuesday, August 03, 2004 4:28 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC:] 16F877A PIN_A0 seems to be tied to PIN_D0 problem


Jim Monteith wrote :

> I'm working on a project and it has come to my attention that
> A0 is driving D0.  I've even written a simple little program
> just to cycle the pins.  If the "D" bank is cycled one bit at
> a time, eveything works fine as long as A0 is low.  Once A0
> goes high, D0 also goes high.
>
> Has anyone seen anything like this before?

Hi !
It's close to impossible to say what's wrong with your
code without seeing it !

Post the shortest possible (but still complete) code example
that shows this "error". Why not your own test program !?

Just one thing, A0, does it goes high and low due to some
external event, or through your code ? It's not clear to me.

(I know nothing about CCS, but I think this will help you anyway :-) )

Best Regards,
Jan-Erik.

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