Erasing flash during RTOS task execution on STM32F4

[SGasp.1]

Hi ..

I am using this function to erase some sectors on the flash

bool FLASH_EraseSectors(uint32_t starting_sector , uint8_t number_of_sectors)
{
	FLASH_EraseInitTypeDef erase_init;
	uint32_t page_error;
 
    /* Erase the user Flash area */
	erase_init.Banks        = FLASH_BANK_1;
	erase_init.TypeErase   	= FLASH_TYPEERASE_SECTORS;
	erase_init.NbSectors 	= number_of_sectors;
	erase_init.Sector     	= starting_sector;
	erase_init.VoltageRange = FLASH_VOLTAGE_RANGE_3;
 
	/* Unlock the Flash to enable the flash control register access *************/
	FLASH_Unlock();
 
	if (HAL_FLASHEx_Erase(&erase_init, &page_error) != HAL_OK)
	{
		FLASH_Lock();
		return false;
	}
	if (HAL_FLASHEx_Erase(&erase_init, &page_error) == HAL_OK)
	{
		FLASH_Lock();
		return true;
	}
 
}

I would like to erase some sectors without breaking the 2 tasks running...

The point is that it seems to destroy the tasks...

Is there a safe way to delete the sectors in flash during a task execution in FREERTOS ?

Thanks a lot

[Walid ZRELLI]

Hello @SGasp.1​ ,

As flash erasing is a blocking and time intensive task, it should on a lower priority task.

Usually, if the erasure is not needed immediately, it is to be performed page per page within a lower task priority.

Otherwise, if you have activated a watchdog, don't forget to feed it between page erasures or it might trigger a reset depending on the flash range to be erased and how much time it would take.

I hope this helps you.

BeST Regards,

Walid

[SGasp.1]

Thanks Walid..

But it is enough to call it one or maybe inside a loop in this way ?

  __disable_irq();
  while (FLASH_EraseSectors(2 ,1) == false)
  {
 
  }
  __enable_irq();

Thanks a lot

[Manny]

What do you mean by 'destroy the tasks'?

[SGasp.1]

Hi Aharm.. thannks for your answer..

I mean can I call these instructions inside a task

  __disable_irq();
  while (FLASH_EraseSectors(2 ,1) == false)
  {
 
  }
  __enable_irq();

without blocking a Higher priority task which is responsible for the communication with another board?

Thanks

[Manny]

The FreeRtos Scheduler uses ISR to perform its task switching, if you disable the interrupts globally, the timer(used by rtos) interrupt will also stop, thus no task switching.

[SGasp.1]

Ok so If I am able to enter in this task where is located the following code

 while (FLASH_EraseSectors(2 ,1) == false)
  {
 
  }

I should be able to erase the sectors..

because I tried without inside a while loop but I wasn't able to delete the sectors calling it just once..

Is it correct ?

Thanks for your huge support ...

Simone

[Manny]

if you want to other task(the communication task) to run make those task higher priority then this task(the flash erase). which Scheduler shame are you using? Cooperative or premtive?

[SGasp.1]

#define configUSE_PREEMPTION           0

Cooperative

[Tesla DeLorean]

Other access to FLASH will stall the processor, for 128KB sectors don't they spec 2seconds worst case.

C​ode footprint needs to run entirely from RAM, or different Flash BANK