arduino_ci doesn't seems to work properly with mega2560

[arduino-ci]

arduino_ci doesn't seems to work properly with mega2560

[ianfixes]

I see a passing build 🎉 https://travis-ci.com/scls19fr/mwe_arduino_ci/builds/97377931

[ianfixes]

It looks like I added a definition for this board, but it's incomplete -- it's missing the compiler flags that are needed for this compilation target. e.g. here's what the definition for leonardo looks like in the default yaml file:

  leonardo:
    board: arduino:avr:leonardo
    package: arduino:avr
    gcc:
      features:
      defines:
        - __AVR_ATmega32U4__
      warnings:
      flags:

That __AVR_ATmega32U4__ is the crucial value, and I don't know what it is (or if there are several, what they all should be).

It appears that not much more is known now than when I first went looking; here are a bunch of search results that just turned up people with the same problem as me:

• "Error compiling for --fqbn arduino:avr:mega (missing cpu flags)" arduino/arduino-cli#17
• "Compiler error: Unknown architecture on mega2560" https://www.avrfreaks.net/forum/compiler-error-unknown-architecture-mega2560
• "Which GCC + avr-libc + arduino for mega2560 actually works?" https://forum.arduino.cc/index.php?topic=66243.0
• "AVR-ATmega2560-GCC/Makefile" https://github.com/matteoserva/ChibiOS-AVR/blob/master/demos/AVR-ATmega2560-GCC/Makefile
• "AVR-GCC with ATMega2560" https://www.avrfreaks.net/forum/avr-gcc-atmega2560-bootloader
• "Do not buy the mega 2560 until gcc is fixed!!" http://forum.arduino.cc/index.php?topic=28269.0

This is a topic I am entirely unqualified to answer; all the existing stuff in the default YAML file came from values I found in other documentation or source files.

If you want to experiment with it (perhaps just using __AVR_ATmega2560__, shown in this gist , I'd copy the following section into your .arduino-ci.yml file and let me know if it works:

  mega2560:
    board: arduino:avr:mega:cpu=atmega2560
    package: arduino:avr
    gcc:
      features:
      defines:
        - __AVR_ATmega2560__
      warnings:
      flags:

[per1234]

Here's a list of all the MCU definition macros for AVR:
https://www.microchip.com/webdoc/avrlibcreferencemanual/using_tools_1using_avr_gcc_mach_opt.html
These are widely used in preprocessor conditionals for part-specific code.

[scls19fr]

Here is my .arduino-ci.yml https://github.com/scls19fr/mwe_arduino_ci/blob/master/.arduino-ci.yml
and build status on Travis https://travis-ci.com/scls19fr/mwe_arduino_ci/builds/97342356

[ianfixes]

Looks like you're missing the toplevel platforms: section. It should look like this:

platforms:
  mega2560:
    board: arduino:avr:mega:cpu=atmega2560
    package: arduino:avr
    gcc:
      defines:
        - __AVR_ATmega2560__

[ianfixes]

@per1234 that's exactly what I'm looking for! If you have a list of all known Arduino platforms, I could really use your help on #89.