Re: [avr-chat] Bootloader stops working

[Ian Caddy]

Hi Christopher,

We had an issue some time ago with our bootloader and a M128.  At random
intervals, some of the boards would loose their flash programs for no
apparent reason.  Of course this problem never happened until more than
50 units were deployed in the field...

It turned out that in our production programming, for some reason we had
not enabled the brown out detection fuse for the processor.

On startup of the brick power supplies we were using, they would saw
tooth up to the operating voltage of +5V.  In the saw tooth, the
processor would get enough voltage to start, but then as the voltage
died again, the processor would keep running, even though the voltage
was not high enough, and illegal instructions were being executed,
which, and I seem to remember an Atmel app note about this somewhere
which I currently don't have, can cause the flash to be erased or
effected by these illegal instructions.

Once we reflashed all the processors with the brown out detected, we
have never had anymore flash problems since then.

So, even if you are using your processor on the bench, it is wise to
enable the brown out detection as when you turn on or off our unit, it
may be executing illegal instructions and causing flash problems.

I hope this helps.

regards,

Ian Caddy
Goanna Technologies Pty Ltd


Christopher X. Candreva wrote:
> I've just had an Mega16 I've been useing with Reza Naima's bootloader and 
> avreflash code, where the bootloader stoped working seemingly all by itself. 
> What's odd is this is a project I hadn't touched since last Sept (04), and 
> the chip reflashed itself the last time I tried.
>
> I've found one reference through google of this hapening to someone else:
>
> http://dragonsgate.net/pipermail/icc-avr/2002-December/000639.html
>
> Following that thread, I use my STK500 to reload the bootloader code, then 
> avreflash was able to reload my code.
>
> Is this a known bug in the chips, bootloader, reflash, the way the chip can 
> be configured ?
>
> -Chris
>
> ==========================================================
> Chris Candreva  -- address@hidden -- (914) 967-7816
> WestNet Internet Services of Westchester
> http://www.westnet.com/
>
>
> _______________________________________________
> AVR-chat mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/avr-chat

--
Ian Caddy
Goanna Technologies Pty Ltd
+61 8 9221 1860