About FreeRTOS

FreeRTOS^TM is a market leading RTOS from Real Time Engineers Ltd. that supports 33 architectures and received 103000 downloads during 2012. It is professionally developed, strictly quality controlled, robust, supported, and free to embed in commercial products without any requirement to expose your proprietary source code.

FreeRTOS has become the de facto standard RTOS for microcontrollers by removing common objections to using free software, and in so doing, providing a truly compelling free software model.

Implementation Quality Management

• FreeRTOS never performs a non-deterministic operation, such as walking a linked list, from inside a critical section or interrupt.

• We are particularly proud of the efficient software timer implementation that does not use any CPU time unless a timer actually needs servicing. Software timers do not contain variables that need to be counted down to zero.

• Likewise, lists of Blocked (pended) tasks do not require time consuming periodic servicing.

• The FreeRTOS queue usage model manages to combine simplicity with flexibility (in a tiny code size) - attributes that are normally mutually exclusive.

• FreeRTOS queues are base primitives on-top of which other communication and synchronisation primitives are build. The code re-use obtained dramatically reduced overall code size, which in turn assists testing and helps ensure robustness.

In addition, the TÜV SÜD certified SIL 3 SafeRTOS real time kernel was originally derived from FreeRTOS, and has undergone the most stringent analysis and test process - the results of which were fed back into the FreeRTOS code base (when commonality still existed).

Mission

The original mission of the FreeRTOS project was to provide a free RTOS solution that was easy to use. That is, easy to build and deploy, on a Windows (or Linux) host computer, without having to figure out which source files are required, which include paths are required, or how to configure the real time debugging environment. This has been achieved through the provision of pre-configured, build-able, example projects for each officially support port.

Naturally, as the FreeRTOS started circa 2003, how these projects are created has evolved for the better, and some original projects remain that don't demonstrate all of the RTOS functionality, or have become stale. However, each project is fully tested before it is added to the FreeRTOS zip file distribution, and many RTOS demo projects undergo active maintenance before each new release. Responding to user feedback, each new demo added to the distribution now also includes a simple "blinky" style getting started configuration to compliment the comprehensive examples.

Design Goals

• Easy to use
• Small footprint
• Robust

FreeRTOS Founder