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.
- Click on System tick timer and set Preemption Priority to 15 (highest possible value).
- Click OK to close the NVIC Configuration dialog.
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.
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:
:
#include "cmsis_os.h"
:
extern uint32_t os_time;
uint32_t HAL_GetTick(void) {
return os_time;
}
:
int main(void)
{
:
osKernelInitialize ();
:
osKernelStart ();
:
Step 4: Remove SysTick_Handler in stm32f7xx_it.c
- STM32CubeMX generates a SysTick_Handler that is in-compatible with CMSIS-RTOS RTX. Remove the code for the SysTick_Handler in the source file stm32f7xx_it.c as shown below.
#if 0
void SysTick_Handler(void)
{
HAL_IncTick();
HAL_SYSTICK_IRQHandler();
}
#endif
Step 5: Build Project in MDK
- Use Project - Build Target to generate the application code.