targets/arduino/target_docs.rst

.. _target-arduino:

-------
Arduino
-------

This target supports building Pigweed on a few Arduino cores.

.. seealso::
   There are a few caveats when running Pigweed on top of the Arduino API. See
   :ref:`module-pw_arduino_build` for details.

Supported Boards
================

Currently only Teensy 4.x and 3.x boards are supported.

+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| Core                                                             | Board Name                                                        | Compiling | Flashing | Test Runner |
+==================================================================+===================================================================+===========+==========+=============+
| `teensy <https://www.pjrc.com/teensy/td_download.html>`_         | `Teensy 4.1 <https://www.pjrc.com/store/teensy41.html>`_          | ✓         | ✓        | ✓           |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `teensy <https://www.pjrc.com/teensy/td_download.html>`_         | `Teensy 4.0 <https://www.pjrc.com/store/teensy40.html>`_          | ✓         | ✓        | ✓           |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `teensy <https://www.pjrc.com/teensy/td_download.html>`_         | `Teensy 3.6 <https://www.pjrc.com/store/teensy36.html>`_          | ✓         | ✓        | ✓           |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `teensy <https://www.pjrc.com/teensy/td_download.html>`_         | `Teensy 3.5 <https://www.pjrc.com/store/teensy35.html>`_          | ✓         | ✓        | ✓           |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `teensy <https://www.pjrc.com/teensy/td_download.html>`_         | `Teensy 3.2 <https://www.pjrc.com/store/teensy32.html>`_          | ✓         | ✓        | ✓           |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `arduino-samd <https://github.com/arduino/ArduinoCore-samd>`_    | `Arduino Zero <https://store.arduino.cc/usa/arduino-zero>`_       |           |          |             |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `arduino-sam <https://github.com/arduino/ArduinoCore-sam>`_      | `Arduino Due <https://store.arduino.cc/usa/due>`_                 |           |          |             |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `adafruit-samd <https://github.com/adafruit/ArduinoCore-samd>`_  | `Adafruit Feather M0 <https://www.adafruit.com/?q=feather+m0>`_   |           |          |             |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `adafruit-samd <https://github.com/adafruit/ArduinoCore-samd>`_  | `Adafruit SAMD51 Boards <https://www.adafruit.com/category/952>`_ |           |          |             |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+
| `stm32duino <https://github.com/stm32duino/Arduino_Core_STM32>`_ |                                                                   |           |          |             |
+------------------------------------------------------------------+-------------------------------------------------------------------+-----------+----------+-------------+

Setup
=====

You must first install an Arduino core or let Pigweed know where you have cores
installed using the ``pw_arduino_build_CORE_PATH`` build arg.

Installing Arduino Cores
------------------------

The ``arduino_builder`` utility can install Arduino cores automatically. It's
recommended to install them to into ``third_party/arduino/cores/``.

.. code:: sh

  # Setup pigweed environment.
  source activate.sh
  # Install an arduino core
  arduino_builder install-core --prefix ./third_party/arduino/cores/ --core-name teensy

Building
========
To build for this Pigweed target, simply build the top-level "arduino" Ninja
target. You can set Arduino build options using ``gn args out`` or by running:

.. code:: sh

  gn gen out --args='
    pw_arduino_build_CORE_PATH="//third_party/arduino/cores"
    pw_arduino_build_CORE_NAME="teensy"
    pw_arduino_build_PACKAGE_NAME="teensy/avr"
    pw_arduino_build_BOARD="teensy40"
    pw_arduino_build_MENU_OPTIONS=["menu.usb.serial", "menu.keys.en-us"]'

On a Windows machine it's easier to run:

.. code:: sh

  gn args out

That will open a text file where you can paste the args in:

.. code:: text

  pw_arduino_build_CORE_PATH = "//third_party/arduino/cores"
  pw_arduino_build_CORE_NAME = "teensy"
  pw_arduino_build_PACKAGE_NAME="teensy/avr"
  pw_arduino_build_BOARD = "teensy40"
  pw_arduino_build_MENU_OPTIONS = ["menu.usb.serial", "menu.keys.en-us"]

Save the file and close the text editor.

Then build with:

.. code:: sh

  ninja -C out arduino

To see supported boards and Arduino menu options for a given core:

.. code:: sh

  arduino_builder --arduino-package-path ./third_party/arduino/cores/teensy \
                  --arduino-package-name teensy/avr \
                  list-boards

.. code:: text

  Board Name  Description
  teensy41    Teensy 4.1
  teensy40    Teensy 4.0
  teensy36    Teensy 3.6
  teensy35    Teensy 3.5
  teensy31    Teensy 3.2 / 3.1

You may wish to set different arduino build options in
``pw_arduino_build_MENU_OPTIONS``. Run this to see what's available for your core:

.. code:: sh

  arduino_builder --arduino-package-path ./third_party/arduino/cores/teensy \
                  --arduino-package-name teensy/avr \
                  list-menu-options --board teensy40

That will show all menu options that can be added to ``gn args out``.

.. code:: text

  All Options
  ----------------------------------------------------------------
  menu.usb.serial             Serial
  menu.usb.serial2            Dual Serial
  menu.usb.serial3            Triple Serial
  menu.usb.keyboard           Keyboard
  menu.usb.touch              Keyboard + Touch Screen
  menu.usb.hidtouch           Keyboard + Mouse + Touch Screen
  menu.usb.hid                Keyboard + Mouse + Joystick
  menu.usb.serialhid          Serial + Keyboard + Mouse + Joystick
  menu.usb.midi               MIDI
  ...

  Default Options
  --------------------------------------
  menu.usb.serial             Serial
  menu.speed.600              600 MHz
  menu.opt.o2std              Faster
  menu.keys.en-us             US English

Testing
=======
When working in upstream Pigweed, building this target will build all Pigweed
modules' unit tests.  These tests can be run on-device in a few different ways.

Run a unit test
---------------
If using ``out`` as a build directory, tests will be located in
``out/arduino_debug/obj/[module name]/[test_name].elf``.

Tests can be flashed and run using the `arduino_unit_test_runner` tool. Here is
a sample bash script to run all tests on a Linux machine.

.. code:: sh

  #!/bin/bash
  gn gen out --export-compile-commands \
      --args='pw_arduino_build_CORE_PATH="//third_party/arduino/cores"
              pw_arduino_build_CORE_NAME="teensy"
              pw_arduino_build_PACKAGE_NAME="teensy/avr"
              pw_arduino_build_BOARD="teensy40"
              pw_arduino_build_MENU_OPTIONS=["menu.usb.serial", "menu.keys.en-us"]' && \
    ninja -C out arduino

  for f in $(find out/arduino_debug/obj/ -iname "*.elf"); do
      arduino_unit_test_runner --verbose \
          --config-file ./out/arduino_debug/gen/arduino_builder_config.json \
          --upload-tool teensyloader \
          out/arduino_debug/obj/pw_string/test/format_test.elf
  done

Using the test server
---------------------

Tests may also be run using the `pw_arduino_use_test_server = true` GN arg.
The server must be run with an `arduino_builder` config file so it can locate
the correct Arduino core, compiler path, and Arduino board used.

.. code:: sh

  arduino_test_server --verbose \
      --config-file ./out/arduino_debug/gen/arduino_builder_config.json

.. TODO(tonymd): Flesh out this section similar to the stm32f429i target docs.

Flashing Known Issues
---------------------

Teensy Boards
^^^^^^^^^^^^^

By default Teensyduino uses the `Teensy Loader Application
<https://www.pjrc.com/teensy/loader.html>`_ which has a couple limitations:

- Requires a GUI (or X11 on Linux).
- Can only flash one board at a time.

GN Target Example
=================

Here is an example `pw_executable` gn rule that includes some Teensyduino
libraries.

.. code:: text

  import("//build_overrides/pigweed.gni")
  import("$dir_pw_arduino_build/arduino.gni")
  import("$dir_pw_build/target_types.gni")

  _library_args = [
    "--library-path",
    rebase_path(arduino_core_library_path, root_build_dir),
    "--library-names",
    "Time",
    "Wire",
  ]

  pw_executable("my_app") {
    # All Library Sources
    _library_c_files = exec_script(
            arduino_builder_script,
            arduino_show_command_args + _library_args + [
              "--library-c-files"
            ],
            "list lines")
    _library_cpp_files = exec_script(
            arduino_builder_script,
            arduino_show_command_args + _library_args + [
              "--library-cpp-files"
            ],
            "list lines")

    sources = [ "main.cc" ] + _library_c_files + _library_cpp_files

    deps = [
      "$dir_pw_hex_dump",
      "$dir_pw_log",
      "$dir_pw_string",
    ]

    include_dirs = exec_script(arduino_builder_script,
                               arduino_show_command_args + _library_args +
                                   [ "--library-include-dirs" ],
                               "list lines")

    # Required for using Arduino.h and any Arduino API functions
    remove_configs = [ "$dir_pw_build:strict_warnings" ]
    deps += [ "$dir_pw_third_party/arduino:arduino_core_sources" ]
  }