modm: a barebone embedded library generator

modm (pronounced like dial-up "modem") is a toolbox for building custom C++23 libraries tailored to your embedded device. modm generates startup code, HALs and their implementations, communication protocols, drivers for external devices, and BSPs in a modular, customizable process that you can fine-tune to your needs.

• This project has a homepage.
• Install the toolchain and explore our examples.
• You can discover the modm library in more detail.
• Easily start your own completely custom project.
• Our CI checks every contribution for regressions.
• We care about testing modm.
• API reference is available here.
• We do quarterly releases with a curated changelog.

This project also has a forum for discussions and a technical blog to document larger design concepts.

• You found a bug? Open up an issue, we don't bite.
• You have a question? We probably have an answer.
• You require a feature? Write it down to get things rolling.
• You want to contribute? Read the contribution guidelines and open a pull request.

modm is optimized for the harsh requirements of the Eurobot competition, where our robots need to run reliably and completely autonomously for the game's 100 second duration. Our robots contain a lot of different microcontrollers, some without a lot of resources, so modm needs to fulfill a diverse set of objectives, like small code size with small memory consumption, predictable program flow, extreme portability.

The library source code is licensed as MPLv2 with any external source code under compatible licenses (BSD, Apache2, MIT). So feel free to fork this project and adapt it to your needs. The only thing we ask of you is to contribute your changes back so everyone can benefit.

Please clone modm recursively, you need all the submodules:

Features

• Efficient and fast object-oriented C++23 API.
• Support for thousands of AVR and ARM Cortex-M microcontrollers from Microchip, STMicroelectronics and Raspberry Pi.
• Build system agnostic: Choose SCons, CMake, Makefile or use your own.
• Modular, data-driven, target-specific HAL generation using the lbuild code generator.
• No memory allocations in HAL with very low overall RAM consumption.
• Highly configurable modules with sensible defaults and lots of documentation.
• Cross-platform peripheral interfaces incl. bit banging:
  • GPIO, External Interrupt and IO expanders.
  • ADC, DAC and Comparators.
  • UART, I²C, SPI, CAN and Ethernet.
• Interfaces and drivers for many external I²C and SPI sensors and devices.
• Debug/logging system with IOStream and printf interface.
• Cooperative, stackless protothreads and resumable functions.
• Cooperative, stackful fibers and scheduler.
• Functional (partial) libstdc++ implementation for AVRs.
• Useful filter, interpolation and geometric algorithms.
• Lightweight unit testing system (suitable for AVRs).
• Hundreds of tests to ensure correct functionality.
• Integration of useful third-party software:
  • FreeRTOS and FreeRTOS+TCP operating system.
  • CMSIS and CMSIS-DSP interfaces.
  • ETL: Embedded Template Library.
  • TinyUSB: USB Host/Device stack.
  • FatFS: FAT/exFAT filesystem.
  • ROSserial: Embedded ROS client.
  • CrashCatcher: Crash reports for HardFaults.
  • printf: Small printf implementation.
  • Nanopb: Embedded Protocol Buffers.
  • LVGL: Embedded Graphics Library.

Microcontrollers

modm can create a HAL for 3839devices of these vendors:

• STMicroelectronics STM32: 3034devices.
• Microchip SAM: 416devices.
• Microchip AVR: 388devices.
• Raspberry Pi: 1device.

Here is a table with all device families and the peripheral drivers they support:

• ✅ Implemented as a software driver in modm.
• ○ Available in hardware but missing a software driver in modm.
• ✕ Unavailable in hardware or device with that peripheral not supported by modm.

Note that this is a summary overview and your specific device may not have all the peripherals in this table. Please discover modm's peripheral drivers for your specific device.

We are only a small team of developers and are limited in the amount of devices we can support and test in hardware. Open a discussion to ask if your specific device is supported out-of-the-box and how you can add it otherwise.

Boards

We have out-of-box support for many development boards including documentation.

Drivers

We also have a number of completely target-independent drivers for external devices connected via I²C, SPI, UART, BitBang, etc. Most of these also give you access to the entire device so you can easily configure them for your specific needs.

Please see our examples for a complete list of tested targets and drivers.

How can I contribute?

The easiest way for you and the best way for us to see if something is unclear or missing, is if you use the library and give us some feedback by filing a bug report or if you have a fix already opening a pull request.

See CONTRIBUTING.md for our contribution guidelines.

The modm project is maintained by Niklas Hauser (@salkinium), Raphael Lehmann (@rleh), and Christopher Durand (@chris-durand) with significant contributions from Sascha Schade (@strongly-typed), Fabian Greif (@dergraaf), Kevin Läufer (@ekiwi), Martin Rosekeit (@thundernail), Daniel Krebs (@daniel-k), Georgi Grinshpun (@georgi-g), David Hebbeker (@dhebbeker), Thorsten Lajewski (@TheTh0r), Mike Wolfram (@mikewolfram), and many more contributors.

Folder structure

examples

Example projects that show the usage of parts of the modm library. These projects are always up to date and are tested to compile by our CI.

src

This folder contains the actual source code of modm grouped into several modules.

test

Contains hundreds of tests for making sure modm works the way we expect it to.

docs

General documentation about this library and how to use it.

ext

Third-party code used in this library.

tools

Support tools, scripts and files.