Raspberry Pico
Introduction
This is how I got started.
Unzip and get the latest compiler from https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads
Cloned the sdk
# Set up directory
export PICO_ROOT=/home/$USER/dev/pico
cd $PICO_ROOT
# Clone SDK
git clone --recurse-submodules https://github.com/raspberrypi/pico-sdk.git
git clone https://github.com/micro-ROS/micro_ros_raspberrypi_pico_sdk.git
# Set up the environment variables, PICO_TOOLCHAIN_PATH being the where you extracted the compiler.
export PICO_SDK_PATH=$PICO_ROOT/pico-sdk
export PICO_TOOLCHAIN_PATH=$PICO_ROOT/gcc-arm-none-eabi-10-2020-q4-major/bin
# Go to test project
mkdir $PICO_ROOT/micro_ros_raspberrypi_pico_sdk
mkdir build
cd build
cmake ..
make