Jump to Freertos application

[Qusai]

Hi all,

I have developed a bootloader for STM32F412, the bootloader works perfectly, however, when I change the user app to be FreeRTOS based, it ceases to work.

I added a blink led in the Hard Fault in both the bootloader and app, but both were not triggered.

Any idea what is going on?

void jump_to_application(void) {
    void (*app_reset_handler)(void);
    uint32_t msp_value = *(volatile uint32_t*)(APP_START_ADDRESS + APP_HEADER_SIZE);
    uint32_t reset_handler_address = *(volatile uint32_t*)(APP_START_ADDRESS + APP_HEADER_SIZE + 4);

    __disable_irq();

    HAL_RCC_DeInit();
    HAL_DeInit();

    SysTick->CTRL = 0;
    SysTick->LOAD = 0;
    SysTick->VAL = 0;


    for (uint32_t i = 0; i < 8; i++)
    {
        NVIC->ICER[i] = 0xFFFFFFFF;
        NVIC->ICPR[i] = 0xFFFFFFFF;
    }

    __enable_irq();

    __set_MSP(msp_value);
    __set_PSP(msp_value);
    __set_CONTROL(0);
    app_reset_handler = (void*)reset_handler_address;
    app_reset_handler();
} 

Thanks in advance.

Regards, 

[TDK]

Nothing wrong with the code posted. If app doesn't work, I wouldn't suspect an issue with the bootloader.

General rules:

• Don't jump to application from within an interrupt.

[KnarfB]

FreeRTOS uses unprivileged access level for tasks. Are you sure the the MCU always has privileged acces level when your bootloader is executed?

hth

KnarfB

[Qusai]

I am not jumping from an interrupt, after flashing is done, the bootloader should jump to the app immediately.

[Qusai]

I am unware of this, enlighten me please. Does it have to do anything with __set_CONTROL(0); ??

[KnarfB]

Yes, and more like setting MSP, manipulating NVIC, ... All details are in the Cortex-M4 Technical Reference Manual.

This only matters if you enter the bootloader from a FreeRTOS thread for example. After reset, everything should work as expected. 

[Qusai]

The bootloader is the main app in my case, and it will check whether the firmware is valid to jump to it, or stay in the bootloader, so I guess, this is irrelevant to my case, right?

[KnarfB]

Right.

Don't you have to set the Vector table offset register (VTOR) to a different value?

You may compare your code to How to Jump to the STM32 Bootloader and Return to the Application. 

hth

KnarfB

[Pavel A.]

Note that FreeRTOS needs VTOR to point to app interrupt vectors, and the 1st word of the vectors be the MSP for interrupts. Does your bootloader sets the MSP for the app to something else?

[Qusai]

I have already done this on app side. Still not working.

In the provided code, 

WRITE_REG(SCB->VTOR, 0x08020200 & SCB_VTOR_TBLOFF_Msk);

 
My understanding is that setting the VTOR in the bootloader will have no effect, since, the app should take care of it. The base address is relevant when setting the MSP value, am I right?