FlightComputer-SRAD-2026

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RP2040 Firmware Build Instructions

This project uses the Raspberry Pi Pico SDK with CMake and the ARM GCC toolchain.

Follow these steps to set up the build environment.

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1. Install dependencies (Linux)

On Debian/Ubuntu:

sudo apt update
sudo apt install cmake gcc-arm-none-eabi libnewlib-arm-none-eabi build-essential git

On Fedora:

sudo dnf install cmake arm-none-eabi-gcc-cs arm-none-eabi-newlib make git

Check installation:

arm-none-eabi-gcc --version
cmake --version

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2. Download the Pico SDK

Clone the SDK somewhere on your system (outside this repo):

git clone https://github.com/raspberrypi/pico-sdk.git ~/pico-sdk

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3. Set the SDK path environment variable

Set this variable so CMake can find the SDK:

export PICO_SDK_PATH=~/pico-sdk

To make it permanent (bash):

echo 'export PICO_SDK_PATH=~/pico-sdk' >> ~/.bashrc
source ~/.bashrc

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4. Build the project

From the code/ directory:

mkdir build
cd build
cmake ..
make -j$(nproc)

After building, the firmware file will be generated:

flight_computer.uf2

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5. Flash to the RP2040

1. Hold the BOOTSEL button on the Pico
2. Plug the Pico into USB
3. Release BOOTSEL
4. Copy the UF2 file:

cp flight_computer.uf2 /media/$USER/RPI-RP2/

(The mount path may vary depending on your system.)

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6. Rebuilding later

After the first build, you usually only need:

cd code/build
make -j$(nproc)

If you change CMakeLists.txt, run:

cmake ..

If something breaks, clean build:

cd code
rm -rf build
mkdir build
cd build
cmake ..
make -j$(nproc)

Submodules / External Libraries

This project uses the SD-card library no-OS-FatFS-SD-SDIO-SPI-RPi-Pico as a Git submodule.

Fresh clone

Clone with submodules:

git clone --recurse-submodules <repo-url>

Existing clone

If the repository was already cloned without submodules:

git submodule update --init --recursive

After pulling updates:

git pull --recurse-submodules
git submodule update --init --recursive

SD-card library notes

This project uses:

no-OS-FatFS-SD-SDIO-SPI-RPi-Pico

in SDIO/PIO 4-bit mode.

The library contains a project-specific patch because the SD clock pin is routed differently on this board.

SD pin mapping:

SD_CMD  -> GPIO18
SD_DAT0 -> GPIO19
SD_DAT1 -> GPIO20
SD_DAT2 -> GPIO21
SD_DAT3 -> GPIO22
SD_CLK  -> GPIO25

The SDIO PIO configuration was modified with:

SDIO_CLK_PIN_D0_OFFSET = 6

The patched submodule commit must be available from the configured submodule remote.