SysTick and FREE Rtos

[TheRaprus]

Hi to everybody.

I'm using H5 and FREE RTOS. I'm porting a project from M3 , than M4 now to H5. I used LL for all the periferals, but moving to HAL isn't a probelm (... but I prefer  LL!).

On M3 and M4 I used a timers to "serve" the RTOS scheduler, then SysTick for a simple delay (yes, also on a task!). E.G. when I need few milliseconds between toggling a output while driving the display.

With H5 I can't use something like "LL_mDelay(100);" because it stuck.

How I can enable systick with H5 (voa MSX CUBE) the LL_mDelay (or HAL_Delay) to measure a time, or simply get a systick?

Thanks in advance.

[David Littell]

In CubeMX configure the SYS Timebase Source to TIM1 (or some other timer (not SysTick!) you don't need for your application).  Leave SysTick for FreeRTOS to use (exclusively).

[TheRaprus]

Hi Devid.

Thanks for the answer.

Using a timer (in my case Tim5) is what I did, and also the CubeMX remeber all the time to switch fron SysTick.

WHat happe is that the  HAL_Delay(x) work fine, but the LL_mDelay(x) stuck. Entering in the source of the LL (file stm32h5xx_ll_utils.c) I found this:

 @note   When a RTOS is used, it is recommended to avoid using blocking delay and use rather osDelay service.
void LL_mDelay(uint32_t Delay){
  __IO uint32_t  tmp = SysTick->CTRL;  /* Clear the COUNTFLAG first */
  uint32_t tmpDelay = Delay;
  /* Add this code to indicate that local variable is not used */
  ((void)tmp);
  /* Add a period to guaranty minimum wait */
  if (tmpDelay < LL_MAX_DELAY)
    tmpDelay++;
  while (tmpDelay != 0U)  {
    if ((SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk) != 0U)    
      tmpDelay--;
  }
}

The "SysTick->CTRL" is 0 and never change, so it stuck! I'll check it again to see what happen without RTOS and in HAL_Delay. I can change LL_mDelay to HAL_Delay but it'a pity!

[Pavel A. · Accepted solution]

@TheRaprus Haven't you also find the note, "When a RTOS is used, it is recommended to avoid using blocking delay and use rather osDelay"? It is quite prominent there.

[TheRaprus]

Hi Pavel.

I copy the intentionally the note (and remove the others), because I know it! But as I wrote in the beginning. I used it on M3 and M4. And they work!