# RT-Thread — Small and Fast Real-Time Operating System for IoT

> A compact open-source RTOS born in China with a rich middleware ecosystem, supporting ARM, RISC-V, MIPS and more for IoT and embedded applications.

## Install

Save as a script file and run:

# RT-Thread — Small and Fast Real-Time Operating System for IoT

## Quick Use
```bash
# Clone RT-Thread
git clone https://github.com/RT-Thread/rt-thread.git
cd rt-thread/bsp/stm32/stm32f407-atk-explorer

# Install env tool and build
pip install scons
scons --exec-path=/path/to/arm-gcc/bin
```

## Introduction
RT-Thread is a small, fast open-source real-time operating system originally developed in China and now used globally. It provides a complete embedded software platform with kernel, middleware components, and IoT connectivity, supporting over 200 BSPs across multiple chip architectures.

## What RT-Thread Does
- Provides a preemptive real-time kernel with thread, timer, and IPC primitives
- Includes a modular component system (filesystem, network, GUI, USB, audio)
- Supports 200+ board support packages for STM32, ESP32, RISC-V, and more
- Offers RT-Thread Smart, a microkernel variant for MPU-class processors
- Provides online package management for adding community components

## Architecture Overview
RT-Thread has a layered architecture: a real-time kernel at the base, a device framework providing unified driver APIs, and optional middleware components on top. The kernel supports 256 priority levels, round-robin scheduling within same priority, and inter-thread communication via mailbox, message queue, and event mechanisms. The FinSH interactive shell enables runtime debugging through a serial console.

## Self-Hosting & Configuration
- Build with SCons, CMake, or IDE integration (Keil, IAR, RT-Thread Studio)
- Use menuconfig (Kconfig-based) to select kernel options and packages
- BSP templates provided for all supported boards
- env tool manages packages and build environment on Windows and Linux
- RT-Thread Studio IDE provides integrated project setup and debugging

## Key Features
- Extremely small footprint: kernel uses only 3KB ROM and 1.2KB RAM minimum
- FinSH command-line shell for runtime inspection and debugging
- POSIX-compatible layer (pthreads, filesystem, sockets) for porting Linux apps
- Online package ecosystem with 400+ community software packages
- RT-Thread Smart variant brings user/kernel space separation for complex applications

## Comparison with Similar Tools
- **FreeRTOS** — Simpler kernel; RT-Thread includes richer built-in middleware
- **Zephyr** — Better Western ecosystem; RT-Thread has stronger Chinese hardware support
- **LiteOS** — Huawei-focused; RT-Thread is vendor-neutral and community-governed
- **uC/OS** — Now open source but less actively developed; RT-Thread has growing ecosystem
- **NuttX** — POSIX-heavy; RT-Thread offers more beginner-friendly tooling

## FAQ
**Q: How small can an RT-Thread application be?**
A: The nano version runs in 3KB ROM and 1.2KB RAM, suitable for Cortex-M0 devices.

**Q: Does RT-Thread support POSIX?**
A: Yes. The POSIX compatibility layer supports pthreads, filesystem operations, and BSD sockets for porting existing code.

**Q: What is RT-Thread Smart?**
A: RT-Thread Smart is a microkernel variant that separates user space from kernel space, targeting application processors like Cortex-A.

**Q: Is there IDE support?**
A: Yes. RT-Thread Studio (Eclipse-based) provides project generation, configuration, debugging, and package management in one tool.

## Sources
- https://github.com/RT-Thread/rt-thread
- https://www.rt-thread.io/document/site/

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Source: https://tokrepo.com/en/workflows/asset-eb8a830c
Author: Script Depot