117 lines
4.5 KiB
Markdown
117 lines
4.5 KiB
Markdown
# lezyne-rear-light-firmware
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**🚧 Work in progress. No complete firmware yet 🚧**
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Open firmware for Lezyne bike rear lights based on ATTINY202
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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`.
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---
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## Table of Contents
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- [Dependencies](#dependencies)
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- [Setup Build Environment](#setup-build-environment)
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- [Building the Project](#building-the-project)
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- [Flashing the Firmware](#flashing-the-firmware)
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- [Reading Flash Content](#reading-flash-content)
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- [Hardware Setup](#hardware-setup)
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- [License](#license)
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---
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## Dependencies
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Ensure the following tools are installed on your system:
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- **GCC AVR toolchain** (supports ATtiny 0/1-series)
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```bash
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sudo zypper install avr-gcc avr-libc
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```
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- **CMake**
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```bash
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sudo zypper install cmake
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```
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- **Python 3, pip and venv**
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```bash
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sudo zypper install python3 python3-pip python3-venv
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```
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- **VS Code** (optional but recommended)
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- **CMake Tools extension** for VS Code
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## Setup Build Environment
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1. Clone the repository:
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```bash
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git clone https://git.mosad.xyz/localhorst/lezyne-rear-light-firmware
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cd lezyne-rear-light-firmware
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```
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2. Configure the CMake project:
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- Open the folder in VS Code.
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- Select the AVR-GCC kit in the bottom blue bar.
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- Run CMake: Configure (from command palette) if it doesn't auto-run.
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## Building the Project
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1. Press F7 or Ctrl+Shift+B to build.
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2. Output files are generated in the 'build/' folder:
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- main.elf → ELF executable
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- main.hex → HEX file (flashable)
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- main.bin → BIN file
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## Flashing the Firmware
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Hardware: FT232 USB-UART adapter connected to UPDI with a 4.7 kΩ resistor.
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1. Create and activate a Python virtual environment:
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```bash
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python3 -m venv pyupdi-env
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source pyupdi-env/bin/activate
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```
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2. Install pymcuprog inside the environment:
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```bash
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pip install pymcuprog
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```
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3. Verify installation:
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```bash
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pymcuprog --version
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```
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4. Flash using pymcuprog:
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```bash
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pymcuprog -t uart -u /dev/ttyUSB0 -d attiny202 write -f build/main.hex
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```
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## Hardware Setup (FT232 → ATtiny202 UPDI)
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```bash
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FT232 TX ----[4.7kΩ]---- UPDI (Pin 6)
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FT232 GND --------------- GND
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VCC -------------------- VCC (3.3V or 5V, must match FT232 logic)
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```
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*Hint:* The GPIO PA0 acts as UPDI of ATtiny202 and needs to be disconnected from the PCB during programming.
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## ATtiny202-SSN Pin Mapping (PCB Usage)
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| Pin # | Pin Name | Port | PCB Usage | Direction |
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|------:|----------|------|--------------------------|------------------------------------------|
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| 1 | VDD | — | +VDD (Power) | Power Input |
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| 2 | PA6 | IO | Green LED | Output |
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| 3 | PA7 | IO | Red LED | Output |
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| 4 | PA1 | IO | LED 1–2 | Output |
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| 5 | PA2 | IO | LED 3–6 | Output |
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| 6 | PA3 | IO | LED 7–8 | Output |
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| 7 | PA0 | IO | UPDI / Activation Button | Input (button, pull-up) / UPDI (program) |
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| 8 | GND | — | Ground | Power Ground |
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---
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### Logic Levels (LEDs & Button)
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| Signal | PCB Usage | LOW | HIGH |
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|--------|-------------------|--------------------------|---------------------------|
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| PA6 | Green LED | LED **ON** | LED **OFF** |
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| PA7 | Red LED | LED **ON** | LED **OFF** |
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| PA1 | LED 1–2 | LED(s) **OFF** | LED(s) **ON** |
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| PA2 | LED 3–6 | LED(s) **OFF** | LED(s) **ON** |
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| PA3 | LED 7–8 | LED(s) **OFF** | LED(s) **ON** |
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| PA0 | Activation Button | Button **pressed** (GND) | Button released (pull-up) |
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## License
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This project is licensed under the MIT License. See [LICENSE](./LICENSE) for details. |