libmcu

A toolkit for firmware development.

libmcu prioritizes simplicity and minimal code size. Dynamic memory allocation is avoided whenever possible, and no linker script tweaks are required.

All code is written in standard C99 for maximum portability. Its modular directory structure, naming conventions, and interface boundaries are designed to be intuitive and scalable across a wide range of embedded platforms.

Documentation for each module is located in its respective subdirectory. You can also find usage examples in examples and test cases in tests.

Feedback, suggestions, and contributions are always welcome.

Project Structure

libmcu is organized into three clear layers:

libmcu/
├── modules/       # Platform-independent logic modules (actor, metrics, pubsub, etc.)
├── interfaces/    # Vendor-neutral HAL abstraction interfaces (UART, GPIO, etc.)
├── ports/         # Platform-specific backend implementations (e.g., STM32 HAL, simulation)
├── project/       # Build integration scripts (e.g., modules.mk, interfaces.mk)
├── tests/         # Unit tests for modules and interfaces
├── examples/      # Integration examples for users

Naming Guidelines

• modules/ contains logic modules that implement platform-agnostic behavior
• interfaces/ defines hardware abstraction interfaces (HAL) that isolate platform-specific details
• ports/ provides platform-specific implementations of those interfaces (e.g., STM32, ESP-IDF)

This structure clearly separates logic, hardware abstraction, and platform adaptation, making the system easier to maintain and extend.

All public symbols follow the lm_ prefix convention to avoid name collisions and to maintain a consistent global namespace.

Modules

• Actor
• Application Timer
• Button
• Buzzer
• Cleanup
• Command Line Interface
• Common
• DFU
• FSM
• Logging
• Metrics
• Power Management
• PubSub
• RateLim
• Retry with exponential backoff
• Runner

Interfaces

• ADC
• BLE
• Flash
• GPIO
• I2C
• KVStore
• PWM
• SPI
• Application Timer
• UART
• WDT
• WiFi

Integration Guide

The library can be integrated into your project as a git submodule, using CMake FetchContent, or downloading manually.

git submodule

Include libmcu into your project

$ cd ${YOUR_PROJECT_DIR}
$ git submodule add https://github.com/libmcu/libmcu.git ${THIRD_PARTY_DIR}/libmcu

Add libmcu into your build system

Make

LIBMCU_ROOT ?= <THIRD_PARTY_DIR>/libmcu
# The commented lines below are optional. All modules and interfaces included
# by default if not specified.
#LIBMCU_MODULES := actor metrics
include $(LIBMCU_ROOT)/project/modules.mk

<SRC_FILES> += $(LIBMCU_MODULES_SRCS)
<INC_PATHS> += $(LIBMCU_MODULES_INCS)

#LIBMCU_INTERFACES := gpio pwm
include $(LIBMCU_ROOT)/project/interfaces.mk

<SRC_FILES> += $(LIBMCU_INTERFACES_SRCS)
<INC_PATHS> += $(LIBMCU_INTERFACES_INCS)

CMake

add_subdirectory(<THIRD_PARTY_DIR>/libmcu)

or

set(LIBMCU_ROOT <THIRD_PARTY_DIR>/libmcu)
#list(APPEND LIBMCU_MODULES metrics pubsub)
include(${LIBMCU_ROOT}/project/modules.cmake)

#list(APPEND LIBMCU_INTERFACES i2c uart)
include(${LIBMCU_ROOT}/project/interfaces.cmake)

# Add ${LIBMCU_MODULES_SRCS} to your target sources
# Add ${LIBMCU_MODULES_INCS} to your target includes

CMake FetchContent

include(FetchContent)
FetchContent_Declare(libmcu
		     GIT_REPOSITORY https://github.com/libmcu/libmcu.git
		     GIT_TAG main
)
FetchContent_MakeAvailable(libmcu)

License

MIT License. See LICENSE file.