We would like to describe how to install the necessary software to develop programs under Zephyr. We will follow the basic procedure as described in the Getting Started Guide of Zephyr.

Directories

We have to determine where we want to put the components to be installed in the directory structure. To always have the same reference we create in our user directory (~) an entry ~/prog:

mkdir ~/prog
cd ~/prog

Update the operating system

$ sudo apt update
$ sudo apt upgrade

Install the Dependencies

Adding from Kitware APT repository

Kitware provides CMake as an Ubuntu package. Therefore, we add it to the APT resources:

sudo apt-get install gpg wget
wget https://apt.kitware.com/kitware-archive.sh

sudo bash kitware-archive.sh we can delete the script after execution:

rm kitware-archive.sh

Install Components

sudo apt install --no-install-recommends git cmake ninja-build gperf \
  ccache dfu-util device-tree-compiler wget \
  python3-dev python3-pip python3-setuptools python3-tk python3-wheel xz-utils file \
  make gcc gcc-multilib g++-multilib libsdl2-dev

Create directory ~/prog/zephyrproject.

This directory will serve as the base for various zephyr components. Starting from the directory ~/prog:

mkdir zephyrproject

or directly from any other directory:

mkdir ~/prog/zephyrproject

Virtual Python environment

Zephyr uses Python scripts which in turn have dependencies. These dependencies may conflict with other (non Zephyr) Python dependencies. The solution to this is to use a virtual Python environment, in which the dependencies are not installed globally but locally in the virtual environment. The consequence is that you have to activate this environment to use the applications it contains.

Installation of python3-venv

sudo apt install python3-venv

Creating the virtual environment:

python3 -m venv ~/prog/zephyrproject/zenv

Activate this environment by calling:

source ~/prog/zephyrproject/zenv/bin/activate

Since this is a bit cumbersome to remember and call we can create an alias. We edit/create the file ~/.bash_aliases with the content

alias zenv="source ~/prog/zephyrproject/zenv/bin/activate"

After that, we can activate the environment by typing zenv.

The environment is deactivated with

deactivate

We activate the environment and continue.

Install Zephyr Sources

West is the meta tool of Zephyr.

pip install west
cd ~/prog/zephyrproject
west init .
west update
west zephyr-export
pip install -r zephyr/scripts/requirements.txt

Install Zephyr SDK Toolchain(s)

We install the minimal sdk variant: (v0.14.2) is to be replaced with the latest revision, see Releases

wget https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.14.2/zephyr-sdk-0.14.2_linux-x86_64_minimal.tar.gz
wget -O - https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.14.2/sha256.sum | shasum --check --ignore-missing

We unpack this archiv to ~/bin, which can also be written as $HOME/bin:

tar -xvf zephyr-sdk-0.14.2_linux-x86_64_minimal.tar.gz -C ~/bin

and run the setup.sh script:

cd ~/bin/zephyr-sdk-0.14.2
./setup.sh -t arm-zephyr-eabi -h -c

With this we install the toolchain for the ARM architecture which should be enough for now.

Build a sample program

cd ~/prog/zephyrproject/zephyr

We build the hello_world example program as cortex m0 emulation.

west build -b qemu_cortex_m0 samples/hello_world

Execution with qemu

west build -t run

Update Zephyr

From time to time we might update Zephyr and our build evironment. We can do this by pulling the latest changes from github and running west update:

cd ~/prog/zephyrproject/zephyr
git pull
west update

Setting Environment Variables

We follow the hints given in Setting Variables. First we extend the zenv alias in file ~/.bash_aliases with the content

alias zenv="source ~/prog/zephyrproject/zenv/bin/activate && source ~/prog/zephyrproject/zephyr/zephyr-env.sh"

Now we only have to using the zenv alias to activate the python evironment and setting the environment variables. The environment variables will be set in the file ~/.zephyrrc to

export ZEPHYR_BASE=~/prog/zephyrproject/zephyr