Dynon embedded Zenoh-Pico application with ZephyrRTOS

This project is based off of the Zephyr Example Application and implements a T3 Forest Topology.

Dependencies

1. Install host dependencies has per Zephyr's Getting Started
2. Install Zephyr SDK

Note: There is probably no need to follow the Zephyr and Python dependencies instructions because Zephyr gets installed when running the west update command locally.

The fun stuff

Building

1. Once Zephyr is properly installed, initialize and update the West Workspace. This step is usually done once or everytime the west.yml manifest file changes. The manifest file is used to express the project's dependencies.

   west init -l
   west update
   west zephyr-export

2. If it's the first time building Zephyr code on your machine, you will need to install Zephyr's Python dependencies.

   pip3 install -r ../zephyr-external/zephyr/scripts/requirements.txt

3. From this directory, build the code:

   west build -d build/nucleo_f439zi -b nucleo_f439zi -p always apps/zenoh-session-restart

   Note: the -d option specifies the output build directory and can be set to whatever directory you want. The only caveat is that at the moment the west_flash_all.sh script expects the build directories to be build/<board>. If you want to change the output build directory, this will affect the build directory option for some of the commands explained in the following sections and you'll have to do flash the "manual" way (ie: use west flash).

   Note2: This repository contains a board definition for the Nucleo-F439zi but it is essentially identical to the Zephyr defined Nucleo-F429zi. It is only present because the hardware we actually use is the F439zi and we don't need the Crypto/Hash Processor at the moment.

Flashing

Flashing is also done through west but has a two different approaches depending on the number or boards that you have connected to your computer:

Script

The simplest method is to use west_flash_all.sh as it works well wether you have one or multiple nucleo boards:

./west_flash_all.sh

Reminder: This script expect the output build directory to be build/<board>

Manual

This require some extra steps if you have multiple boards but allows you to provide any build directory if that's your current situation.

• One board connected to your computer:

  west flash -d build/nucleo_f439zi

  Change the build directory if needed.

• Many boards connected to your computer:

  Getting a list of the connected boards:

  pyocd list

  This will give a list of unique IDs for the ST-Link that are on the Nucleo boards, not the STM32 chip.

  Flashing the board:

  west flash -d build/nucleo_f439zi -r openocd --cmd-pre-init 'adapter serial <STLINK_SERIAL_NUM>'

Debugging

Zephyr provide a gdb debug interface through the west command. It is possible to debug or attach to an already running piece of code. The command is similar to the west flash command but with debug or attach instead of flash

• One board connected to your computer:

  west <debug|attach> -d <build dir>

  Change the build directory if needed.

• Many boards connected to your computer:

  Flashing the board:

  west <debug|attach> -d <build dir> -r openocd --cmd-pre-init 'adapter serial <STLINK_SERIAL_NUM>'

Modifying project config

Zephyr provides a menuconfig interface to change the OS configuration similar to buildroot. The input of the config is stored in prj.conf and various config overlays you provide. To view that menu based on the board you are building for:

west build -d <build dir> -b <board> -t menuconfig

The recommended workflow is to use menuconfig to search for configs and their dependencies. Once you found the dependency you want to turn on or off, add it to the project's prj.conf. It can also be useful to make changes through menuconfig and then press [D] to Save minimal config. Note the file that it gets saved to (typically build/nucleo_g474re/zephyr/kconfig/defconfig) and copy paste to your project's prj.conf.