It supports most processors. FreeRTOS can provide support for threads or tasks, coroutines, mutexes, semaphores, and software timers. There is a tick-less mode designed for compact, low-power ...

[Michael Becker] has been using FreeRTOS for about seven years. He decided to start adding some features and has a very interesting C++ class wrapper for the OS available. Real Time Operating ...

Something like ChibiOS (‘Chibi’ meaning ‘small’ in Japanese), or FreeRTOS (here no points for originality). Perhaps more accurately, FreeRTOS could be summarized as a multi-threading ...