nekoboard-hs

A custom keyboard firmware written for Arduino in Haskell Copilot.

Usage

The bridge between Haskell and C lies in copilot-spec.hs. Read Copilot documentation and add your high-level firmware logic starting from that file. Basically, it operates on streams of data (somewhat similar to lazy lists), which arrive discretely each time the Copilot step() function is called. One can compose streams, e.g. take two streams and produce a stream of sums of the two streams at each time step. Then a spec is written which assigns triggers to Stream Bools.

The C part is in sketch.cpp. Ideally, this contains only primitive IO and the absolute minimum of reliable (i.e. well-tested) code. The Haskell side can access any exported (i.e. non-static) symbol: function, global variable, global array. You also have to provide triggers on the C side: functions which will be called whenever certain clause of the Copilot spec is violated. They are handling the output of your firmware computation, and ideally they're small, simple and focused.

Thanks to the Makefile the Copilot code is compiled and executed to generate copilot-c99-codegen/copilot.{c,h} just when they are needed to be compiled and linked against the sketch.o to produce the final firmware. The firmware can be uploaded simply via make upload.

Dependencies

• Arduino, the software. Probably you'll want to test this on a real hardware board too. I used a SparkfunFun ProMicro 3.3V, so in Makefile you see the path to alternative Arduino core from Sparkfun. That is also the reason of old arduino-1.0.5 installed locally.

Off course you can adapt the arduino part or even get rid of it altogether. Forks welcome.

Edit Makefile and set the path to Arduino in ARDUINO_DIR.

• arduino-mk. In Ubuntu:

   $ sudo apt-get install arduino-mk
  

  Edit Makefile and set the path to it in ARDMK_DIR (matches default for Ubuntu).

• Also tune MONITOR_PORT to point at your device's serial.

• Haskell. I hope you already know something about it; if not, http://learnyouahaskell.com/ — this is a great tutorial.

  In Ubuntu:

   $ sudo apt-get install haskell-platform
  

• Check that have the most recent Cabal:

   $ sudo apt-get install cabal-install
   $ cabal update
   $ cabal install cabal-install
   $ cabal update
  

• Install Copilot:

   $ cabal install copilot
  

• This code also assumes that you have make.