How to change SCB->VTOR in app (stm32f4 HAL)?

Question

I build the bootloader for STM32F4 and build user app with the changes the VECT_TAB_OFFSET value manually for SCB->VTOR in system_stm32f4xx.c file but If I do it in the application. It's not working properly.

I called the SCB->VTOR = 0x8040000 at the beginning of the main() but it didn't work. BOOTLOADER USER APPLICATION

Answer 1

The STM32 startup code calls SystemInit() before main() . SystemInit() sets the SCB->VTOR value (among other things). SystemInit() is implemented in the vendor provided file system_stm32f4xx.c . You can customize the value that gets assigned to SCB-VTOR by editing the value of VECT_TAB_OFFSET , which is also defined in system_stm32f4xx.c . (There should be a copy of system_stm32f4xx.c in your project folder that you can customize for your project.)

If you need different values of VECT_TAB_OFFSET for your boot and application programs then you can use a preprocessor statement like this. (This allows the boot and application programs to use the same copy of system_stm32fxx.c . Alternatively you could use different copies of the file for each program.)

#ifdef BOOT
#define VECT_TAB_OFFSET  0x00 /*!< Vector Table base offset field.
                                   This value must be a multiple of 0x200. */
#else
#define VECT_TAB_OFFSET  0x80000
#endif

Answer 2

Just add this code in main, first line before any other initialization, before HAL_Init or between /* USER CODE BEGIN 1 / / USER CODE END 1 */

__disable_irq();
SCB->VTOR = 0x8008000;
__DSB();
__enable_irq();

Don't forgot to preserve bootloader memory window in ld file:

FLASH    (rx)    : ORIGIN = 0x8008000,   LENGTH = 2048K - 0x8000

That's all, even debugger will run this code w/o bootloader in Stm32CubeIDE at offset 0x8008000, but w/o debugger you must have bootloader at start of flash.

Answer 3

Delete the VTOR set in the startup file. It should not be there.

Set the VTOR in the bootloader before passing the control to the application