HelloErlang

This demonstrates a simple Nerves project that's written in Erlang.

Erlang-izing a Nerves project

Making Nerves support Erlang or more about deleting the Elixir parts that are added with the new project generator. Currently we only support using Elixir's mix build tool in the top level project, but you should be able to use other tools like rebar3 in dependencies.

The following describes what needed to be done after creating a Nerves project the "normal" Elixir-based way using mix nerves.new <project_name>.

The first step is to delete the lib and test directories and all of the code inside of them. Didn't that feel good?

The next step is to update the rel/vm.args.eex and delete everything that starts the Elixir shell. Look for -noshell and delete from there to the end.

Finally, create a src directory and put your Erlang code in there like you would a normal Erlang project.

Building

Building follows the standard Nerves recipe. Here's an example:

export MIX_TARGET=bbb
mix deps.get
mix firmware

And then burn an SD card using mix firmware.burn.

Using

The images pull in the standard nerves_pack infrastructure for bringing up networking and other initialization steps. See the config/config.exs for network parameters and other configuration.

Running

Attach to the console of your board (i.e., RPi3 is HDMI, BBB/RPi0 is USB gadget). You should see prints from the application. Note that the first boot takes quite a bit longer than the rest since it initializes the application's writable filesystem.

To see log messages, run:

> 'Elixir.RingLogger':next().