FreeRTOS is one of the market-leading real-time operating systems (RTOS) for embedded microcontrollers. It is professionally developed, strictly quality controlled, robust, supported (archive), free to use in commercial products without a requirement to expose proprietary source code, and has no IP infringement risk.

CMSIS-RTOS v2 is a common API for real-time operating systems (RTOS). It provides a standardized programming interface that is portable to many RTOS and enables software components that can work across multiple RTOS systems. It supports the Armv8-M architecture, dynamic object creation, multi-core systems, and has a binary-compatible interface across ABI-compliant compilers.

Using this software pack, users can choose between a native FreeRTOS implementation or one that adheres to the CMSIS-RTOS2 API and uses FreeRTOS under the hood. The CMSIS-RTOS2 API enables programmers to create portable application code to be used with different RTOS kernels (for example Keil RTX5).

This documentation shows you:

how to create a new microcontroller project using FreeRTOS from scratch.
various examples show you the usage of FreeRTOS in native and CMSIS-RTOS2 mode.
the technical data of this implementation.
Revision history.

License

The CMSIS-FreeRTOS implementation is provided free of charge by Arm under the Apache 2.0 License.
See the Apache 2.0 License.

The FreeRTOS kernel source files are released under the MIT License.
See the MIT License.

CMSIS-FreeRTOS Pack

The ARM::CMSIS-FreeRTOS pack contains the following:

File/Directory	Content
📂 CMSIS/RTOS2	CMSIS-RTOS2 compliant implementation of FreeRTOS.
📂 Documentation	This documentation.
📂 Source	FreeRTOS kernel source code.
📄 ARM.CMSIS-FreeRTOS.pdsc	Pack description file in CMSIS-Pack format.
📄 LICENSE	License Agreement (Apache 2.0 + MIT).