Example scaffold for an ESP32 Zephyr project.

Prerequisites

The following tools must be installed:

• cmake
• dtc
• python

Workflow

Create a new local workspace directory

mkdir esp32-zephyr-scaffold-ws

Clone the repo into the workspace

cd esp32-zephyr-scaffold-ws
git clone https://github.com/yourname/your-app.git

`

Create a Python virtual environment

python3 -m venv .venv

Activate it

source .venv/bin/activate

Install west

pip install west

Initialize West from the application (manifest) directory

cd esp32-zephyr-scaffold
west init -l .

Download the dependencies in the workspace

cd ..
west update

Install Python requirements

pip install -r deps/zephyr/scripts/requirements.txt

Source the environment script

source deps/zephyr/zephyr-env.sh

Now you can build

cd esp32-zephyr-scaffold-ws
west build -b esp32_devkitc_wroom/esp32/procpu .

MCUboot must be built and flashed at least once. It can be built with sysbuild with:

west build -p always -b esp32_devkitc_wroom/esp32/procpu --sysbuild .

and flashed with:

west flash

The application only can be built with:

west build -p always -b esp32_devkitc_wroom/esp32/procpu .

View the serial output with:

west espressif monitor

Install TKinter in the system inorder to use the guiconfig:

sudo apt install python3-tk

This can be used for setting debug flags: https://docs.zephyrproject.org/latest/develop/tools/clion.html#configure-zephyr-parameters-for-debug Use the guiconfig target and click the hammer icon.

When making these changes, they are "temporarily" saved: Configuration saved to '/home/mchernosky/dev/hello_world/cmake-build-esp32/zephyr/.config' To permanently make the changes, you would add them to a .conf file.

CLion setup

Open the project at the workspace directory (the topdir) -- not the application.

Right click on the CMakeLists.txt file in the application directory and select "Load West Project."

Configure a new toolchain which uses the environment script from the project directory instead of the global installation. Use a west build, but configure it to use the new toolchain. Then you can select the board in the west settings.

Configure a run configuration for the native sim build by setting the "Target" to native_runner_executable and the "Executable" to build/zephyr/zephyr.exe.

native_sim build

The application can be built for the native_sim target with:

west build -p always -b native_sim .

And started by running:

./build/zephyr/zephyr.exe

This will log output to the console, and show the device used for the UART simulation. Then you can connect to it with minicom or similar.

Networking in native_sim

In order to use networking with the native sim build, before running the application use the network setup script ot configure the host network interface:

sudo deps/tools/net-tools/net-setup.sh --config nat.conf start

This runs the net-setup.sh script from the net-tools directory with the nat.conf configuration file. This sets up the host interface that the application will connect to, runs a DHCP server on the interface and configures network address translation (NAT) for internet access.

Now when the application is run, it will get an IP address from the host.

You should be able to ping the host address with:

uart:~$ net ping 192.0.2.2                                                                                                                                                                              
PING 192.0.2.2                                                                                                                                                                                          
28 bytes from 192.0.2.2 to 192.0.2.13: icmp_seq=1 ttl=64 time=60 ms                                                                                                                                     
28 bytes from 192.0.2.2 to 192.0.2.13: icmp_seq=2 ttl=64 time=10 ms                                                                                                                                     
28 bytes from 192.0.2.2 to 192.0.2.13: icmp_seq=3 ttl=64 time=20 ms 

You should also be able to ping out the internet, for example with:

uart:~$ net ping 8.8.8.8                                                                                                                                                                                
PING 8.8.8.8                                                                                                                                                                                            
28 bytes from 8.8.8.8 to 192.0.2.24: icmp_seq=1 ttl=114 time=30 ms                                                                                                                                      
28 bytes from 8.8.8.8 to 192.0.2.24: icmp_seq=2 ttl=114 time=40 ms                                                                                                                                      
28 bytes from 8.8.8.8 to 192.0.2.24: icmp_seq=3 ttl=114 time=50 ms

DNS resolution should also work. For example:

uart:~$ net dns www.google.com                                                                                                                                                                          
Query for 'www.google.com' sent.                                                                                                                                                                        
dns: 142.250.72.36                                                                                                                                                                                      
dns: All results received

When finished running the application, then run:

sudo deps/tools/net-tools/net-setup.sh --config nat.conf stop

to remove the network configuration.

Running on ESP32

Configure your WiFi network by setting the CONFIG_WIFI_SSID and CONFIG_WIFI_PASSWORD Kconfig variables. For security, this can be done in an overlay config file and added to the build with:

west <commands> -- -DOVERLAY_CONFIG=overlay-wifi-file.conf

Serial console

To connect the serial console on the ESP32, run west espressif monitor.

TODO

• Only pull espressif dependencies for Zephyr? This would make west update faster.