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[avr-gcc-list] Re: Troubles uploading to a Mega103
From: |
Ludovic COURTES |
Subject: |
[avr-gcc-list] Re: Troubles uploading to a Mega103 |
Date: |
Fri, 30 Mar 2001 12:33:01 +0200 |
Hi !
> We had the same problem with both the signature bytes being 1)FF FF FF and
> being 2)00 01 02:
> 1)The ATMega103 loses its signature bytes for some reason after a few
> erase/program cycles. The workaround is to change the UISP code. I made a
> couple of changes already to the software already to accomodate these
> defects (also to read/write fuse bits, correcting srec format downloads,
> etc.). I can give you or anyone else this code if you so wish.
Ok, but why would it lose its signature bytes ? I modified Uisp to force upload/
download even if signature bytes are wrong but the flash remains filled with
0xff's.
Anyway, I am interested in your changes to uisp (i agree, there are some defects
to fix) and i think you should send a patch to add your changes to the official
version.
> 2)Are you holding in the reset line using an external reset while you are
> talking to the ATMega103? If the external reset is kept LOW the signature
> bytes will be FF FF FF when a
> "uisp -dapa" command is performed but after that the signature bytes will be
> 00 01 02 when a
> "uisp -dapa" command is performed. Make sure the reset line is not
> externally made LOW when the UISP talks to it.
No reset is not held down. But we had /PEN (Programming Enable) connected to
the GND instead of VCC (MCU was always in programming mode)... ;) And now we
have changed it, signature bytes are always 0xffffff (except if we lock it).
Thanks,
Ludovic.
--
Ludovic Courtès
Université de Technologie de Belfort-Montbéliard
Unitec (Club de Robotique de l'UTBM)