Multi-threading on MCUs Sample Clauses

Multi-threading on MCUs. Threading on MCUs is approached in multiple ways rang- ing in flexibility and memory requirements. Protothreads are stackless threads that provide an abstraction over state machine processes for sensor networks and can be interleaved [12]. Protothreads are similar to tasks in the sense that they can be interleaved but differ in the sense that they are imperative programs and share their stack with other threads but therefore cannot have local variables. Moreover, they must always be defined within the same function. There are also more general solutions available for doing multiple things at the same time on MCUs that generally do not work anymore on the very small ones. TinyOS is an OS designed for sensor systems that compiles to a static firmware for MCUs [13]. Threads in TinyOS differ from tasks in the sense that they are im- perative and event driven using explicit atomicity annotations. Other solutions use a full-fledged Real-time Operating System (RTOS) such as ChibiOS, mbed or RTOS that just do not run on small MCUs. For example, QDuino that builds on the Quest kernel [14] or RT-Arduino, the Arduino extension offering an interface to the RTOS provided by the Xxxxx kernel [15]. All these solutions have real threads and therefore require much faster MCUs than required for mTask.