STM32Cube  Version 2.0
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Add CMSIS-RTOS RTX

This section explains how to add the CMSIS-RTOS RTX real-time operating system.

Setup in STM32CubeMX

In STM32CubeMX ensure that the System Tick Interrupt is set to the lowest priority (which is the highest number).

Configuration tab

  • Under System open NVIC Configuration. Set the following:
    • Group priority using at least 1-bit for pre-emption
    • SysTick and PendSV: lowest pre-emption priority (highest possible value)
    • SVC: one pre-emption priority higher than SysTick/PendSVC
  • Click OK to close the NVIC Configuration dialog.
NVIC.png

Setup in MDK

In MDK, the steps to add the CMSIS-RTOS RTX real-time operating system to a project that is configured with STM32CubeMX are:

Step 1: Add CMSIS-RTOS RTX

  • Open the Manage Run-Time Environment window and add CMSIS:RTOS (API):Keil RTX.
rte_bsp_rtx.png

Step 2: Configure CMSIS-RTOS RTX parameters

  • Open the configuration file RTX_Conf_CM.c from the project window, component group CMSIS.
  • Optionally you may change to the Configuration Wizard tab.
  • Change the following settings:
    • Main Thread stack size [bytes] 1024
    • RTOS Kernel Timer input clock frequency [Hz] set to core clock frequency
  • Save the file.

Step 3: Add code for CMSIS-RTOS RTX in 'main.c'

  • Open the source file main.c from the project window, source group STM32CubeMX:Common Sources and add code lines in the sections USER CODE BEGIN / USER CODE END as shown below:
    :
    /* USER CODE BEGIN Includes */
    #include "cmsis_os.h" // ARM::CMSIS:RTOS:Keil RTX
    /* USER CODE END Includes */
    :
    /* USER CODE BEGIN 0 */
    extern uint32_t os_time;
    uint32_t HAL_GetTick(void) { // Add HAL_GetTick function for STM32Cube HAL
    return os_time;
    }
    /* USER CODE END 0 */
    :
    int main(void)
    {
    :
    /* USER CODE BEGIN 1 */
    osKernelInitialize (); // Initialize RTOS Kernel for setup
    /* USER CODE END 1 */
    :
    /* USER CODE BEGIN 2 */
    osKernelStart (); // Begin thread switching
    /* USER CODE END 2 */
    :

Step 5: Build Project in MDK

  • Use Project - Build Target to generate the application code.