Re: [avr-chat] Difficulty writing eeprom with JTAGICE3

[Juergen Harms]

I have now invested some time to install Atmel Studio on a Windows 7 
partition, and to check how Atmel Studio writes to eeprom.

Short Summary
-------------
- Installing and getting started with Atmel Studio is a pain in the
  neck if you are used to nice avrdude and to installing rpm packages
  (and, why does Studio use -v for specifying options with 2 perfectly
  different semantics in a single line?).

- The effort to install Atmel Studio is nevertheless worth while, even
  if, later, you only use avrdude: it allows you to get the latest
  firmware update for your jtagice3 (for me that meant an upgrade from
  firmware version 1.37 to version 2.21).

- However, the firmware upgrade does not solve the problem discussed
  here.

- Failures on single-byte eeprom write operations do not only occur
  with Avrdude, but also with Atmel Studio - maybe somewhat less
  frequently than with Avrdude, but so often that the jtagice3 is
  practically useless if you want to write to eeprom positions.

- It looks like the problem is not necessarily due to the
  implementation of Avrdude (or Atmel Studio) but could just as well
  be a flaw in the implementation of the firmware of the jtagice3.

- To be repeated here: corresponding single-byte operations work
  perfectly when using a JTAG ICE mkII - nevertheless, I will now
  confection a new target board with a new processor to make sure that
  the problem is not a due to the specific processor I am using.


Detailed description
--------------------
In the attachment, I join a file into which I have pasted the console 
I/O for both a single-byte read and a single-byte write, and both for 
Avrdude and for Atmel Studio. Atmel Studio only has a simple -v option, 
which does not provide much information on how Studio proceeds when it
writes to eeprom.


Juergen

interactive
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