# lezyne-rear-light-firmware

Open firmware for Lezyne bike rear lights based on ATTINY202

This repository contains a minimal firmware as a **C project** for the ATtiny202 microcontroller using **GCC**, **CMake**, and **VS Code**. It also includes instructions for programming the chip using an **FT232 USB-UART adapter** via the UPDI interface with `pymcuprog`.  

---

## Table of Contents

- [Dependencies](#dependencies)
- [Setup Build Environment](#setup-build-environment)
- [Building the Project](#building-the-project)
- [Flashing the Firmware](#flashing-the-firmware)
- [Reading Flash Content](#reading-flash-content)
- [Hardware Setup](#hardware-setup)
- [License](#license)

---

## Dependencies

Ensure the following tools are installed on your system:

- **GCC AVR toolchain** (supports ATtiny 0/1-series)  
  ```bash
  sudo zypper install avr-gcc avr-libc
    ```
- **CMake**
  ```bash
    sudo zypper install cmake
    ```
- **Python 3, pip and venv**
  ```bash
    sudo zypper install python3 python3-pip python3-venv
    ```
- **VS Code** (optional but recommended)
- **CMake Tools extension** for VS Code

## Setup Build Environment
1. Clone the repository:
   ```bash
    git clone https://git.mosad.xyz/localhorst/lezyne-rear-light-firmware
    cd lezyne-rear-light-firmware
    ```
2. Configure the CMake project:
    - Open the folder in VS Code.
    - Select the AVR-GCC kit in the bottom blue bar.
    - Run CMake: Configure (from command palette) if it doesn't auto-run.

## Building the Project
1. Press F7 or Ctrl+Shift+B to build.
2. Output files are generated in the 'build/' folder:
- main.elf → ELF executable
- main.hex → HEX file (flashable)
- main.bin → BIN file

## Flashing the Firmware
Hardware: FT232 USB-UART adapter connected to UPDI with a 4.7 kΩ resistor.
1. Create and activate a Python virtual environment:
   ```bash
    python3 -m venv pyupdi-env
    source pyupdi-env/bin/activate
    ```
2. Install pymcuprog inside the environment:
   ```bash
    pip install pymcuprog
   ```
3. Verify installation:
   ```bash
    pymcuprog --version
   ```
4. Flash using pymcuprog:
   ```bash
    pymcuprog -t uart -u /dev/ttyUSB0 -d attiny202 write -f build/main.hex
   ```
## Hardware Setup (FT232 → ATtiny202 UPDI)
   ```bash
    FT232 TX ----[4.7kΩ]---- UPDI (pin 6)
    FT232 GND --------------- GND
    VCC -------------------- VCC (3.3V or 5V, must match FT232 logic)
   ```

## License

This project is licensed under the MIT License. See [LICENSE](./LICENSE) for details.