Open-source alternatives to Rt Thread

FreeRTOS-Kernel is a real-time operating system kernel for microcontrollers. It provides a multitasking environment through a priority-based task scheduler, an embedded memory manager, and an inter-process communication framework to ensure time-critical tasks meet their deadlines. The kernel includes a software timer engine for executing functions at predefined intervals or after set delays. It supports a minimal model of concurrent tasks and lightweight co-routine execution for systems with limited memory resources. The project covers a broad surface of embedded resource management, includi

Mbed OS is a real-time operating system designed for connected internet-of-things devices and microcontroller hardware. It provides a fundamental framework that combines a real-time operating system with an embedded security framework, a hardware abstraction layer for controlling sensors and peripherals, and a device management platform for cloud-based orchestration. The system establishes security foundations to protect connected products from unauthorized access and vulnerabilities. It further enables remote monitoring and hardware orchestration by connecting embedded devices to cloud servi

embedded-notes is a collection of technical study guides and development notes focused on embedded Linux, Linux kernel internals, and C programming. It serves as a reference for embedded systems development and a preparation resource for technical interviews in the field. The project provides detailed documentation on writing device drivers, managing virtual memory, and understanding kernel internals. It also includes guides on IoT network protocols, such as MQTT and TCP/IP, and outlines the architectural details of chip architectures and hardware peripherals. The material covers a broad sur

The Espressif SoC Development Framework is a comprehensive toolset for developing, compiling, and flashing applications targeting Espressif system-on-chips. It serves as an embedded toolchain orchestrator and a hardware abstraction layer that simplifies the control of low-level peripherals, memory mapping, and chip-specific registers. The framework provides a dedicated IoT connectivity stack for implementing Wi-Fi, Bluetooth, Zigbee, and Ethernet communication on microcontrollers. It also includes an embedded real-time operating system integration layer to manage multitasking and scheduling o

AliOS-Things is a scalable operating system for internet-connected devices. It provides an embedded firmware framework and runtime for managing hardware peripherals, network connectivity, and secure data execution across diverse CPU architectures. The system includes an edge AI inference engine for processing audio and image patterns locally without cloud dependencies. It also features a cloud connectivity SDK for automated onboarding, remote diagnostics, and log reporting, alongside a scripting engine for executing high-level code on resource-constrained hardware. Connectivity is handled th

NuttX is a POSIX-compliant real-time operating system designed for resource-constrained embedded environments. It functions as a scalable microcontroller OS that provides a Unix-like environment for managing hardware and running applications across architectures ranging from 8-bit to 64-bit. The system ensures high software portability by implementing a kernel that follows POSIX and ANSI standards. This allows developers to create portable embedded applications using standardized API calls across diverse hardware architectures. The project includes a modular kernel architecture and a hardwar

MicroPython is a lean implementation of Python 3 optimized to run on microcontrollers and other resource-constrained systems. It serves as a cross-platform embedded runtime and hardware abstraction layer, providing a firmware framework that maps high-level software commands to specific microcontroller registers across diverse processor architectures. The project functions as an embedded language interpreter that enables rapid prototyping on hardware through an interactive read-eval-print loop. It supports a wide range of target environments, including ARM, ESP32, STM32, RISC-V, and WebAssembl

Lua RTOS for ESP32 is a real-time operating system designed for ESP32 microcontrollers that integrates a lightweight Lua interpreter to manage hardware resources and application logic. It utilizes a micro-kernel architecture to provide preemptive task scheduling, ensuring deterministic timing and reliable concurrency for embedded operations on resource-constrained hardware. The system distinguishes itself by providing a unified hardware abstraction layer that maps high-level programming commands directly to peripheral registers. This allows developers to interact with sensors, actuators, and

TencentOS-tiny is a real-time operating system for microcontrollers designed to manage task scheduling and resource allocation across various hardware modules. It functions as an embedded platform and modular kernel for deploying real-time software on different chip architectures. The system includes built-in protocol stacks to enable secure data transmission and connectivity between terminal IoT devices and cloud platforms. The project covers real-time task management, embedded software deployment, and microcontroller administration. It utilizes a modular microkernel architecture and a har

This project is flight control autopilot software designed as a real-time operating system for managing the flight dynamics and navigation of autonomous multicopters, fixed-wing aircraft, and rovers. It serves as a multi-vehicle autopilot framework that supports various aircraft configurations, including vertical takeoff and landing platforms across industrial environments. The system includes a MAVLink communication stack for exchanging telemetry and command data between unmanned vehicles and ground control stations. It also provides a software-in-the-loop flight simulator to test autopilot

NuttX is a POSIX-compliant real-time operating system designed for microcontrollers ranging from 8-bit to 64-bit architectures. It provides a deterministic execution environment with a real-time task scheduler and a POSIX embedded kernel to ensure portable code execution across diverse hardware targets. The project distinguishes itself through a comprehensive hardware abstraction layer that provides standardized drivers for I2C, SPI, CAN, and USB across various semiconductor chipsets. It also features an embedded networking stack supporting TCP, UDP, IPv4, and IPv6, alongside industrial proto

This project is a monolithic operating system kernel designed to serve as the foundational software layer for diverse computing architectures and embedded platforms. It manages core system services, including processor scheduling, memory allocation, and hardware resource distribution, to facilitate communication between user applications and physical hardware. The kernel utilizes a hardware abstraction layer and platform-specific device trees to ensure consistent operation across a wide variety of processors and specialized computing devices. It supports dynamic functionality through loadable

This project is a bare-metal operating system developed for ARM64 architecture. It serves as a low-level implementation of kernel engineering, focusing on the fundamental construction of an OS from the hardware level up. The system is distinguished by its comprehensive approach to ARM64 processor control, featuring a red-black tree task scheduler and a hierarchical page table system for virtual memory management. It implements a sophisticated privilege model that handles transitions between kernel and user modes, ensuring process isolation through address space splitting and exception level m

ZSWatch is a real-time operating system for wearable devices featuring a touch display and Bluetooth Low Energy connectivity. It provides a comprehensive software suite that includes a Bluetooth LE communication stack, an embedded UI framework for round displays, and a complete firmware toolchain for compiling, flashing, and simulating wearable hardware. The project is distinguished by its specialized wearable capabilities, such as a graphical framework for designing reactive screens and watchfaces via a visual editor. It implements a publish-subscribe messaging system to decouple hardware se

Embassy is an asynchronous framework for microcontrollers that provides a runtime for cooperative multitasking. It enables the execution of multiple concurrent tasks to maximize energy efficiency and CPU usage, utilizing an async executor that puts the processor to sleep when idle. The framework includes a comprehensive set of embedded components, featuring a hardware abstraction layer for peripherals like GPIO, SPI, I2C, and UART, alongside a TCP/IP network stack and a USB device stack. It also provides a Bluetooth Low Energy host stack for wireless communication and a bootloader framework t

FreeRTOS is a real-time operating system for embedded devices that provides a kernel for predictable task execution. It utilizes priority-based preemptive scheduling and deterministic timing to manage simultaneous hardware tasks. The project includes a symmetric multiprocessing kernel that distributes processing workloads across multiple CPU cores using a shared memory architecture. It also provides a thread-safe TCP/IP networking stack for managing internet protocol traffic and IPv6 connectivity on embedded processors. The system incorporates an embedded memory manager with fixed-size alloc

This project is a Lua-based firmware environment for the ESP8266 WiFi chip, providing an embedded Lua interpreter and a development framework for WiFi SoC hardware. It functions as a C-based wrapper around the Espressif non-OS SDK, enabling the execution of asynchronous scripts to manage wireless communication and hardware peripherals. The environment integrates a SPIFFS flash filesystem for storing persistent scripts and data directly on non-volatile memory. To optimize limited hardware resources, the system utilizes execute-in-place flash execution, running read-only constants and instructi

F Prime is a component-based framework designed for the development and deployment of embedded and spaceflight software. It provides a modular architecture that decouples software logic from communication interfaces, allowing developers to define system structures through a domain-specific modeling language. This model-based approach enables automated code generation, ensuring consistency across complex system topologies while maintaining strict interface contracts between software modules. The framework distinguishes itself through its integrated build system and ground data operations suite

This project is an educational curriculum designed to teach the fundamentals of operating system development and low-level systems programming. It provides a structured sequence of lessons and code samples that guide users through building a functional kernel and bootloader from scratch, enabling a practical understanding of how software interacts directly with computer hardware. The repository distinguishes itself by focusing on the core mechanics of bare-metal execution. It covers the implementation of essential system components, including assembly-based bootloaders that transition process

Contiki is an operating system designed for resource-constrained embedded devices and the Internet of Things. It provides a lightweight, event-driven kernel that enables multitasking and low-power wireless network connectivity on hardware with extremely limited memory and processing power. The system distinguishes itself through a stackless threading model that allows for a blocking-style programming interface while maintaining a minimal memory footprint. It supports dynamic module and firmware management, enabling the loading and linking of relocatable binary code at runtime to update applic

OpenWrt is a modular Linux distribution designed for resource-constrained networking hardware. It functions as a comprehensive network routing platform, providing a complete build environment that allows users to generate custom firmware images for a wide variety of embedded processor architectures. By utilizing a standardized cross-compilation toolchain and a package-based ecosystem, it enables the creation of tailored operating systems for specific hardware deployments. The project distinguishes itself through a hardware abstraction layer that normalizes interactions across diverse chipsets

CS-Xmind-Note is a collection of structured mind maps and conceptual diagrams serving as a comprehensive knowledge base for computer science fundamentals. It functions as an academic reference and study guide, organizing core subjects into a visual mapping of interdependent technical concepts. The project utilizes an XMind-compatible schema to model complex domains through hierarchical nodes and relational concept mapping. This approach allows for the visual representation of technical layers, linking hardware specifications to software abstractions. The knowledge base covers several primary

This project is a C-based heap management library designed for systems programming environments that require manual control over memory lifecycles. It provides the fundamental utilities necessary to initialize a designated region of memory and perform dynamic allocation and deallocation of memory blocks. The library utilizes a linked-list-based tracking system to manage memory segments, employing a first-fit strategy to locate available space within the heap. To maintain memory organization and minimize fragmentation, it implements boundary-tag coalescing, which automatically merges adjacent

This project is an open-source software development kit and framework for implementing the Matter smart home standard. It provides a universal IPv6-based application layer and a cluster-based data model to ensure interoperability between diverse smart home devices and controllers. The system is distinguished by its multi-transport network abstraction, which maps Bluetooth LE, Thread, and Wi-Fi implementations to a common layer. It includes specialized tooling for secure device commissioning via QR codes and NFC, as well as a comprehensive over-the-air firmware update system for distributing s

miniaudio is a single-file C audio library used for audio playback, capture, and hardware interfacing across multiple operating systems. It functions as an audio hardware abstraction layer, an audio processing engine, an audio synthesis engine, and a codec and resampler. The project implements a node-graph based system for routing digital audio signals, mixing, and 3D spatialization. It also includes a programmatic generator for noise patterns and basic waveforms used for sound creation and signal testing. The library covers digital signal processing, including audio format conversion and sa

This project is an OpenWrt firmware builder and specialized Linux router distribution designed to repurpose Amlogic S9xxx series hardware into functional routers. It provides a hardware adaptation layer consisting of kernel modifications and drivers that enable the operating system to run on Amlogic ARM SoC devices. The project features an automated firmware pipeline for scheduling, building, and distributing custom images. It includes a device recovery toolkit for bootstrapping, flashing, and restoring factory images, and supports the conversion of devices previously running different mobile

SDL is a cross-platform development library that provides low-level access to audio, keyboard, mouse, joystick, and graphics hardware. It functions as a hardware abstraction layer, mapping diverse operating system interfaces into a unified set of functions to ensure consistent performance across different computing environments. The library serves as a foundation for multimedia and interactive application development by providing an integrated audio processing engine and a graphics rendering framework. It manages the complexities of hardware communication by normalizing raw input events and p