Difference between revisions of "STM32 FreeRTOS"

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=== Semaphores and Mutexes ===
 
=== Semaphores and Mutexes ===

Revision as of 06:18, 30 October 2024

FreeRTOS Middleware.png

FreeRTOS is a real-time operating system for embedded systems. On MCUs based on ARM Cortex-M cores a standardised API exists which is known as CMSIS RTOS. This API is built on top of FreeRTOS. Two different versions of CMSIS RTOS exists: v1 and v2. Except from the queue handling they are almost identical.

STM32CubeMX includes an option to use FreeRTOS. In an earlier life, I did quite a lot of development on ESP32, and that, due to it's dual-core design, is very much centred around FreeRTOS. Back the, I grew to hate FreeRTOS.

The examples on this page is using a STM32F411 based Black Pill development board.

Concepts

While FreeRTOS call itself a "real-time operating system" it is essentially merely a task manager and scheduler.

Multiple tasks can be created and each task will have it's own reserved stack and heap space.

Tasks

Tasks are essentially an endless loop and the task can operate in one of four different states:

  • Running
  • Blocked
  • Suspended
  • Ready

STM32CubeIDE

Queues can be added and modified through STM32CubeMX. Here is a list of queues:

STM32CubeIDE FreeRTOS Queues.png

Clicking "Add" or double clicking on any of the existing tasks will pop up an edit window:

STM32CubeIDE FreeRTOS Edit Task.png

Semaphores and Mutexes

To be added

Queues

To be added

Example

Miscellaneous Links