Set unused bits of extended fuse to 1

[descampsa]

Avrdude has changed the way it handle unused bits in the extended fuse for atmega 328 and atmega 168, they are now at 1 instead of 0.
See http://svn.savannah.nongnu.org/viewvc?view=rev&root=avrdude&revision=1335 for more info.
This causes avrdude to fail when one try to write the fuse with the unused bits at 0, because the value it read back is not the same than the one it tried to write. This commit fixes the fuse value for all boards that use atmega328 or 168.

See also issue #5175

I only tested that fix with a usbasp programmer on arduino uno, it would probably be good that someone test it with other programmer/board (especially one atmega168) to be sure.

Update: According to the discussion in #5175 , the patch indeed fix the problem for Atmega328 with usbasp, USBtinyISP and ArduinoISP.
A separate but related issue appears with AVRISP mkII programmer, but this issue can't be easily fixed in Arduino code alone, avrdude.conf has to be changed.

[per1234]

Just a clarification, I tested with Tools > Programmer > Arduino as ISP, which is an Arduino running the ArduinoISP sketch. I didn't test with Tools > Programmer > ArduinoISP because I don't own that programmer.

[per1234]

You missed one: https://github.com/descampsa/Arduino/blob/1e162f52d92282cd0dce7c828793b9a938d26547/hardware/arduino/avr/boards.txt#L459

[descampsa]

Yes, thanks, it's fixed.

[per1234]

I successfully tested Burn Bootloader on all ATmega168 based boards in this boards.txt using USBasp, Arduino as ISP, USBtinyISP, and Atmel AVRISP mkII(with arduino/avrdude-build-script#2 applied).

[matthijskooijman]

This looks like a good change to me. I think it would be good if a second person would verify the new settings against the datasheet, to prevent accidental changes. And of course testing, I think @facchinm was planning to do some testing as well.

[descampsa]

@facchinm

Should'nt this patch be included in #5374?
It is not strictly essential, but currently the avrdude warning is printed at upload.
Seems kind of strange to not fix our own warnings ;-)

[facchinm]

@descampsa
we simply can't update the core this way because it would break backwards compatibility (in fact, this modification only works with avrdude 6.3). Updating the AVR core standalone (without the tools) on older installations is possible and would be much more difficult to solve (without patching avrdude 6.0.1).

But sooner or later we'll surely merge it 😄

[matthijskooijman]

@facchinm, huh? but a core / platform specifies what versions of the tool it needs in the JSON? Or did I misunderstand something here?

[facchinm]

Yes, but only in the json, so fetching the core manually will leverage on installed tools (or latest tools if the IDE is > 1.6.10 but this is a corner case)

[matthijskooijman]

You mean when someone manually copies the arduino/avr directory out of git? That doesn't sound like a usecase we need to support?

[facchinm]

There were a couple of other cases which I can't remember right now, but I'm not saying we shouldn't merge this patch,I would only give give people some time to update their tools 😄