[avrdude-dev] [bug #34027] avrdude AT90S1200 Problem

[Joerg Wunsch]

Follow-up Comment #2, bug #34027 (project avrdude):

The problem appears to be the specific AT90S1200 requirements after a
chip erase operation.  The datasheet says:

3. If a Chip Erase is performed (must be done to erase the Flash),
   wait tWD_ERASE after the instruction, give RESET a positive pulse,
   and start over from step 2. [...]

The latter is attempted by calling pgm->initialize again after the
chip erase, but that (obviously) doesn't relly release the /RESET line
as mandated by the datasheet.

As a workaround, separate the "chip erase" and "program device" steps
as follows:

. First, call AVRDUDE with the -e option to perform the chip erase
  operation.

. Then, perform the actual programming using the -D option to prevent
  AVRDUDE from executing the implied chip erase.

As already explained in a private email, accidentally erasing or
manipulating the signature bytes on the AT90S1200 could easily happen.
Use the -F option to override the signature check.


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