STM32 FreeRTOS Library for Arduino

This is a port of FreeRTOS for STM32 as Arduino libraries.

For more information about FreeRTOS, visit the FreeRTOS Web Site. Also, See the very useful Getting Started page.

This library provides 2 FreeRTOS versions:

• 9.x
• 10.x:
  • 10.0.1
  • 10.2.1
  • 10.3.1

Each have been modified by ST (See st_readme.txt in FreeRTOS Source).

These are the same provided with the STM32Cube MCU Packages. Or thanks to STMicroelectronics GitHub organization: stm32_mw_freertos.

Configuration

FreeRTOS has several configuration options, which can be specified from within the FreeRTOSConfig.h file.

This library provides a default FreeRTOS configuration file named FreeRTOSConfig_Default.h.

User can provide his own FreeRTOS configuration file at sketch level by adding his configuration in a file named STM32FreeRTOSConfig.h.

Or add extra FreeRTOS configuration to the default at sketch level by adding an extra configuration in a file named STM32FreeRTOSConfig_extra.h.

Heap allocation schemes are provided by FreeRTOS, see Memory allocation implementations included in the RTOS source. To extend those schemes a thread-safe heap allocation using C runtime (Newlib) has been added based on Dave Nadler work:

http://www.nadler.com/embedded/newlibAndFreeRTOS.html

By default, the heap_useNewlib.c is used. It can be changed thanks a define in the configuration file:

/* Define memory allocation implementations to use:
 * 1 to 5 for heap_[1-5].c
 * -1 for heap_useNewlib_ST.c
 * Default -1 see heap.c
 */

Since v10.0.1, CMSIS-RTOSv2 can be used instead of default CMSIS-RTOS.

configUSE_CMSIS_RTOS_V2 has to be defined and set to 1 to use CMSIS-RTOSv2.

Limitations

• MPU: not supported.
• No CMSIS-RTOSv2 support provided. It is provided as example.
• On Cortex-M0 and Cortex-M0+, all IT are disabled between xTaskCreate() and vTaskStartScheduler(). So it is not possible to use IT inbetween, like Serial.print() ... This is the reason why, in example "frLiyLayland", between xTaskCreate() and vTaskStartScheduler(), we use direct printf(), which will access directly USART without interrupt

Files & Configuration

• STM32FreeRTOS.h : Must always be #include first. It references required include files.
• STM32FreeRTOSConfig.h : If exist at sketch level, it contains the FreeRTOS configurations.
• STM32FreeRTOSConfig_extra.h : If exist at sketch level, it contains extra FreeRTOS configurations.
• FreeRTOSConfig_Default.h : Contains the default FreeRTOS configurations for this STM32 port if STM32FreeRTOSConfig.h doesn't exist.

Test results (using Arduino_Core_STM32)

STM32FreeRTOS v9.0.x

STM32FreeRTOS v10.0.x

* PASSED with configUSE_NEWLIB_REENTRANT set to 0 due to small RAM.

STM32FreeRTOS v10.2.x

* PASSED with configUSE_NEWLIB_REENTRANT set to 0 due to small RAM.

STM32FreeRTOS v10.3.1