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Re: [avr-chat] Chip running too hot ?! :-/

From: Vincent Trouilliez
Subject: Re: [avr-chat] Chip running too hot ?! :-/
Date: Tue, 26 Jun 2007 15:58:01 +0200

"Graham Davies" <address@hidden> wrote:
> I have an ATmega32 DIP right here.  I left it on overnight.  It is not
> possible to feel any temperature rise above ambient.
> What software is it running?  What hardware is it connected to?
> Could there be outputs shorted driving in the opposite direction?
> Can you erase the chip and see if that helps?  Can you isolate it
> from other circuitry?

Oh... thanks Graham (and Shashank), I think indeed I had a problem with
external circuitry causing some pins to source some current.
I had disconnected pretty much everything but 4 pins. My test program
set all pins as output, and when high, 4 of the pins where actually
sourcing some current into adjustable resistors (that were previously
used to drive analog inputs). I had disconnected the common +5V supply
of all 4 pots so they don't conflict with the pins now configured as
outputs, but of course that didn't keep the outputs from now injecting
current into the lower branch of the pots, to the ground. The pots were
of fairly low resistance, so the resulting current was not so low.

I have now completely disconnected the pots, let the AVR run for an
hour, and indeed, it's cold/ambient to the touch, yeepee...

Thanks all for your replies. Yes, I do feel stupid, and I apologize for
wasting every body's time...


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