FreeRTOS On STM32F4xx With Debugging

1. Introduce

• FreeRTOS is a real-time operating system kernel for embedded devices that has been ported to 35 microcontroller platforms
• FreeRTOS is designed to be small and simple. To make the code readable, easy to port, and maintainable, it is written mostly in C, but there are a few assembly functions included where needed (mostly in architecture-specific scheduler routines).
• FreeRTOS provides methods for multiple threads. A tick-less mode is provided for low power applications.
• FreeRTOS kernel features:
  • Pre-emptive or co-operative operation
  • Very flexible task priority assignment
  • Software timers
  • Queues
  • Binarysemaphores
  • Countingsemaphores
  • Recursivesemaphores
  • Mutexes
  • Tick hook functions
  • Idle hook functions
  • Stack overflow checking
  • Trace hook macros

2. FreeRTOS Structure & Hierarchy

• Download sources:

 https://sourceforge.net/projects/freertos/files/FreeRTOS/

FreeRTOS
  ├── Demo             (Contains demo application for every official FreeRTOS port)
  ├── Test             (contains the tests performed on common code and the portable layer code)
  └── Source           (Core FreeRTOS kernel file)
      ├── include      (Consists of The core FreeRTOS kernel header files)
      └── portable     (Consists of Processor specific code)
          ├── Compiler (Contains all the ports created by compiler)
          ├── MemMang  (Contains The sample heap implementations)
          └── ...

• Structure & Hierarchy:

FreeRTOS.h
   ├── FreeRTOSConfig.h        (Application specific configuration options)
   ├── projdefs.h              (Basic FreeRTOS definitions)
   └── portable.h              (Definitions specific to the port being used)
         ├── portmacro.h
         └── mpu_wrappers.h

FreeRTOS.h
   ├── list.c
   ├── croutine.c
   ├── timers.c
   ├── heap_?.c
   ├── queue.c
   └── tasks.c

3. Goal

• Understanding various RTOS concepts with FreeRTOS Programming and Debugging
• Using STM32 Standard Peripheral Driver APIs to configure peripherals
• FreeRTOS Debugging using SEGGER SystemView Software
• Using FreeRTOS API with code examples
• Learn Complete Step by step method to run FreeRTOS on STM32 MCUs using OpenSTM32 System Workbench
• ...

4. Prepare

Software	Hardware
OpenSTM32 System Workbench	Board NUCLEO-F446RE
SEGGER SystemView	Cable
FreeRTOS v10.1.1	Led
STM32F4 standard peripherals library	Button
minicom