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Arduino

Arduino in RIOT. More...

Detailed Description

About

This module enables users to run unmodified Arduino sketches in RIOT. For this we aim at supporting the full Arduino API.

The support of the Arduino API in RIOT is useful for multiple reasons:

Refer to Arduino API for the actual API documentation

General usage

To run your Arduino sketch in RIOT, just follow these steps:

  1. create an empty application
  2. add the arduino module to your application, your Makefile should now look something like this:
    APPLICATION = YOUR_APP_NAME
    BOARD ?= YOUR_TARGET_PLATFORM
    RIOTBASE ?= PATH_TO_RIOT_ROOT
    USEMODULE += arduino
    include $(RIOTBASE)/Makefile.include
  3. copy your Arduino sktech(es) into your application folder. Currently they must have the file ending *.sketch to be processed.
  4. build, flash, and run your application the usual RIOT-way: simply call make all, make flash, make term, etc.

Thats all. As bonus you can of course use any existing RIOT code inside your Arduino sketches - you simply have to add the includes to your sketch and the corresponding modules to your Makefile.

Note
So far, all Arduino sketches MUST have the file ending *.sketch to be recognized by RIOT's build system

Concept

For enabling RIOT to run Arduino sketches, we extended the build system to handle *.sketch files and we implemented the Arduino API using RIOT's native functions.

Extension of the build system

Building Arduino sketches in RIOT is done in a two step process.

First, the make system calls a dedicated Arduino build script, which is called from the Makefile.include of the RIOT Arduino module.

This script creates a temporary file called '_sketches.cpp' inside the application folder. Into this file, the script copies some Arduino glue code ( pre.snip and post.snip) together with the contents of all *.sketch files contained in the application folder.

Second, the RIOT make system is called as usual, processing the temporary file containing all the Arduino code. Simple :-)

Implementation of the Arduino API

For supporting the Arduino API, we have created our own function and class definitions, using the exact same signatures as in the original Arduino header files. These headers are then implemented using standard RIOT APIs, e.g. the peripheral drivers, xtimer, etc.

Add Arduino support to a board

Note
As prerequisite, the board must have support for C++.

To add Arduino support to a board, it has to provide the following:

In RIOT/board/BOARD/include/arduino_board.h:

In addition, you have to add the 'arduino' feature to the board. For this, just add FEATURES_PROVIDED += arduino to the 'other features' section in your board's `Makefile.features'.

That's it, your board can now run Ardunio sketches.

Open issues

Todo:

Make it possible to bootstrap Arduino code manually from any RIOT application. Include a pseudomule as e.g. arduino_base, which does not implement a main function calling setup() and loop(), so these functions have to be called manually from a RIOT application.

Implement analog outputs (PWM mapping)

Implement analog inputs (ADC mapping)

Implement SPI interface class

Add support for the 'Wire Library' (I2C)

Add means to include various Arduino Libraries (maybe as pkg?)

Implement anything else that is missing...

Adapt Arduino build script, so sketches do not have to have the file ending *.sketch anymore

Modules

 Arduino API
 Implementation of the Arduino API in RIOT.