Re: [avr-gcc-list] ATMega32 fuse bit problem

[Vincent Trouilliez]

On Thu, 16 Aug 2007 20:34:25 +0100
James Pascoe <address@hidden> wrote:
> Hi All,
> 
> Apologies for the following question which is very OT, but there is a
> good chance you guys can help.

Hi James,

Yes this is off-topic, but it would be perfectly spot on topic on the
sister list of avr-gcc : "avr-chat":

http://lists.nongnu.org/mailman/listinfo/avr-chat

just subscribe and anything you might ask about the avr will be at home
there ;-)

> I am using an ATMega32 and inadvertantly programmed the fuse bits wrong
> :-( ... instead of setting
> the fuse bits to use a 16 Mhz external crystal as the clock source, I
> programmed the chip to use the low frequency
> crystal oscillator setting. Of course now, I can not program the device
> anymore.
> 
> Does anybody know if there is any way (other than getting hold of a
> 32.768 Khz crystal) that I can recover the device ?
> 
> Many thanks for any suggestions,


I use an ATmega32 too, and I think I did that mistake too ! 
I was suggested to drive the chip directly, by supplying a TTL clock
signal on the XTAL1 pin of the chip, using a signal generator. I
remember at 400KHz it allowed avrdude to chat with the AVR chip just
fine, letting me reconfigure the fuse bits properly, but at 100KHz and
lower, it stopped working. SO just use something in the order of 500KHZ
or higher, and it should work :-)
If you don't have a signal generator, it should be easy to DIY a
simple/dirty clock generator/oscillator to get you out of trouble.

HTH

--
Vince