Dual-bank mode to switch and boot with the firmware present in the Bank-2 of the flash from the Bank-1

[shabaz704]

Hi,

I am using LED blink firmware generated using CUBE-MX by Disabling all the modes and Clearing the pinouts.

I flashed one firmware in the bank-1 (0x08000000) and

second firmware(with few changes the way the led blinks) flashed into the bank-2 (0x08018000) using the stm32 programmer.

First I writing the firmware-2 into bank-2 like this.

 

Next I am flashing the firmware-1 in the bank-1 and running .

I kept the bank switch logic in firmware-1.

My main() fun will look like this:

int main(void)
{
  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();
 
  /* Configure the system clock */
  SystemClock_Config();
 
  /* Initialize all configured peripherals */
  MX_GPIO_Init();
 
  __HAL_RCC_SYSCFG_CLK_ENABLE();
 
  int i = 9;
 
  while (i > 0)
  {
	 // printf("LED BLINK\n");
    /* USER CODE END WHILE */
	HAL_GPIO_WritePin(GPIOB, greenLed_Pin, GPIO_PIN_RESET);
	HAL_Delay(1000);
	HAL_GPIO_WritePin(GPIOB, greenLed_Pin, GPIO_PIN_SET);
	HAL_Delay(1000);
	i--;
  }
  	HAL_FLASH_Unlock();
  	HAL_FLASH_OB_Unlock();
 
	FLASH_OB_BootConfig(OB_BOOT_BANK2);
 
	if(READ_BIT(SYSCFG->CFGR1, SYSCFG_CFGR1_MEM_MODE) == 0)
	{
		HAL_GPIO_WritePin(GPIOB, RedLed_Pin|BlueLed_Pin, GPIO_PIN_SET);
		HAL_Delay(2000);
		HAL_GPIO_WritePin(GPIOB, RedLed_Pin| BlueLed_Pin, GPIO_PIN_RESET);
		HAL_Delay(2000);
		SET_BIT(SYSCFG->CFGR1, SYSCFG_CFGR1_UFB);
		if(READ_BIT(SYSCFG->CFGR1, SYSCFG_CFGR1_UFB) == 1)
		{
			HAL_GPIO_WritePin(GPIOB, BlueLed_Pin, GPIO_PIN_SET);
			HAL_Delay(2000);
			HAL_GPIO_WritePin(GPIOB, BlueLed_Pin, GPIO_PIN_RESET);
			HAL_Delay(2000);
			HAL_GPIO_WritePin(GPIOB, greenLed_Pin, GPIO_PIN_RESET);
			HAL_Delay(2000);
		}
		else
		{
			HAL_GPIO_WritePin(GPIOB, RedLed_Pin, GPIO_PIN_SET);
			HAL_Delay(2000);
			HAL_GPIO_WritePin(GPIOB, RedLed_Pin, GPIO_PIN_RESET);
			HAL_Delay(2000);
			HAL_GPIO_WritePin(GPIOB, greenLed_Pin, GPIO_PIN_RESET);
			HAL_Delay(2000);
 
		}
	}
  	HAL_FLASH_OB_Lock();
	HAL_FLASH_Lock();
 
  NVIC_SystemReset();
 
}

Leds I kept for the debug. The code is executing till the leds BLUE and RED glowing together and fading (line 36) after that I am not able to see the leds. So I am thinking it got stuck at

SET_BIT(SYSCFG->CFGR1, SYSCFG_CFGR1_UFB);

Is this aporach is right? Anything else is required? Please suggest?

Thanks

Shabaz

[Bubbles]

Thank you @GLASS​ - while it's demonstrable (AN4767) that it's actually possible to safely switch bank from within flash, there's a lot of things to take care of to do it reliably. I agree that doing it in SRAM is the easiest safe option.

J.