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Dev1
Dev1
Associate II
April 9, 2019
Question

Use of "HAL_Delay" after "osThreadCreate"

  • April 9, 2019
  • 3 replies
  • 6984 views

Hi all,

I am working with the Nucleo-L476RG board.

I generated a project with CubeMx and enabling FreeRTOS.

At this point the project is running fine.

I debug the project and all is working.

I put a breack point inside the "SysTick_Handler" and this hadler is always launching.

Now, in main function, I add "HAL_Delay(1000)" after creation of the default task with "osThreadCreate" function:

0690X000008A7VVQA0.png

When I debug this code, the "SysTick_Handler" is never launching.

And the code hangs in the "HAL_Delay" function where "HAL_GetTick()" function returns always 0.

I read at https://community.st.com/s/question/0D50X00009XkYFaSAN/freertos-stm32-tick

that If Iwant to use HAL_Delay() before vTaskStartScheduler (osKernelStart), I need to check scheduler state before call xPortSysTickHandler:

I add this check in "SysTick_Handler":

0690X000008A7qYQAS.png

BUT the problem persists because the "SysTick_Handler" was never launched.

Can anyone please found the cause of this problem.

I now that I can overwrite the "HAL_Delay" function since it is "weak", but I need to know the cause of this problem.

Is there any missing configuration ?

Thank you.

3 replies

Sirac
Sirac
Associate II
April 9, 2019

Do you call a function like System_clockConfig ?

You need to init the systick and Irq, otherwise it will never start:

 HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
 HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);
 HAL_NVIC_SetPriority(SysTick_IRQn, 15, 0);

Dev1
Dev1Author
Associate II
April 9, 2019

The problem is after adding "HAL_Delay" function.

SysTick_Handler is launched before adding "HAL_Delay" line code in main function.

As I said "I put a breack point inside the "SysTick_Handler" and this hadler is always launching."

"HAL_SYSTICK_Config(SystemCoreClock/1000UL)" was called in "HAL_Init()".

"RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;" and "HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0)" are called in "SystemClock_Config"

"HAL_NVIC_SetPriority(SysTick_IRQn, 15, 0);" was called in "HAL_Init()".

Thanks.

Sirac
Sirac
Associate II
April 9, 2019

A ok. For me it works but for you, firstly, remove this:

" if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED)"

beacause it's already done in the osSystickHandler.

The HAL tick and the Os tick are completly independant. Normally, you have to use the TIM 1 as timer for the HAL tick. Is it done ?

If you use HAL_Delay, is your code is blocked ? or it continue to run ?

Rob.Riggs
Rob.Riggs
Senior
March 15, 2023

I just ran into this issue and I thought I would leave an answer which explains what is happening for anyone else experiencing this issue and how to avoid it. FreeRTOS raises the NVIC base priority as soon as any FreeRTOS function (such as osThreadCreate) is called. This disables most interrupts, including SysTick. It is only after the scheduler starts that the the NVIC priority is lowered to normal, re-enabling interrupts.

It is best to do all of the FreeRTOS/CMSIS-OS initialization in one block, doing nothing else within that block. Everything else should be done either before the first FreeRTOS call or within a FreeRTOS thread.

It would be helpful if the STM32CubeIDE templates included this information in a comment in main().

Reference: https://www.freertos.org/FreeRTOS_Support_Forum_Archive/December_2012/freertos_Using_interrupts_before_kernel_starts_6447124.html

    Y
    Yassine1
    Graduate II
    July 30, 2024

    Thanks @Rob.Riggs very helpfull.

    So is there anyway to overcome this issue ?

    Rob.Riggs
    Rob.Riggs
    Senior
    July 30, 2024

    @Yassine1 I don't think there is anything to overcome -- one just needs to be aware of the issue and write one's code accordingly.

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