Using a Simulated Device

This guide covers building and running the Ocre runtime using Zephyr’s native_sim target - a simulated environment that allows you to test Ocre applications without physical hardware. This approach is particularly useful for initial development and testing.

There are two key limitations when building the native simulator:

  1. Building on ARM architectures is not currently supported due to a lack of 32-bit support.
  2. The POSIX architecture does not work on macOS due to fundamental differences between macOS and other Unix-like operating systems.

For users affected by these limitations, we recommend using one of the following alternatives:

  • A Linux-based x86_64 development container. (Feel free to use the Ocre Dev Container you obtained when setting up your dev environment.)
  • A computer with a x86_64 architecture
  • Emulating a Linux-based VM with x86_64 architecture

Steps

1. Install Dependencies and Zephyr SDK

Complete the Install dependencies and the Install the Zephyr SDK sections for your host operating system from the Zephyr (v3.7.0) Getting Started Guide.

Currently the Ocre runtime is built on Zephyr 3.7.0. As a result, the links in the above section reference v3.7.0 documentation and not the latest documentation. It is advised to follow the links in this guide to ensure compatibility with your device.

2. Create a Virtual Python Environment (venv)

Create a Python virtual environment (venv) to isolate your Python project dependencies.

mkdir runtime && cd runtime
python3 -m venv .venv
source .venv/bin/activate

You may need to install the python3-venv package (or equivalent) on your host system beforehand.

3. Install WEST

Install the west CLI tool, which is needed to build, run and manage Zephyr applications.

pip install west

4. Initialize the workspace

Now, initialize the ocre-runtime repo.

west init -m https://github.com/project-ocre/ocre-runtime.git

Lastly, update the repo with the west utility.

west update

This step may take 5-10 minutes as it pulls all Zephyr Project board sources.

5. Install Additional Zephyr (pip) requirements

In order to build the Ocre runtime properly, you’ll need to install a few remaining requirements for Zephyr.

pip install -r zephyr/scripts/requirements.txt

6. Build the application

The following will build the firmware for the virtual, native_sim target which will allow you to run the Ocre runtime on a simulated device, rather than a physical board.

west build -b native_sim ./application -d build -- -DMODULE_EXT_ROOT=`pwd`/application

You can also run the West Build task directly from the Ocre Workspace file as defined in the Ocre Workspace File reference. If you do, be sure to select native_sim as your build target from the dropdown list of available boards.

7. Run the application

To run the application, simply run the following command:

./build/zephyr/zephyr.exe

If successful, you should see the following output:

Next Steps

Now that you have successfully built and flashed the Ocre runtime to your device, you’re ready to create your first Ocre application. Head over to Your First Container to get started building containerized applications.