Bootloader STM32 interrupt problem

I made a bootloader that makes it possible to program the device in application. The bootloader software uses interrupts and communicate over an RS485 bus. When I jump to the base address of my firmware, it seems that the interrupts aren't working. I use the command below to redirect the vectortable in the firmware.

NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x08008000);

The method of jumping to my applicaton is the one documented in the AN2557.

static const uint32_t FIRMWARE_START_ADDRESS = 0x08008000ul;
typedef void (*pFunction)(void);

...

//Initialize jump to firmware
uint32_t startAddress = *(__IO uint32_t*)(FIRMWARE_START_ADDRESS + 4);
pFunction RestartFirmware = (pFunction)startAddress;
//Initialize firmware Stack Pointer */
__set_MSP(*(__IO uint32_t*)FIRMWARE_START_ADDRESS);

I've tested the code and the jump occurs, and the code is run, but none of my interrupt driven deviced work properly.

I've tested the code by using the example from the AN2557 to jump to the my bootloader (recompiled to address 0x08002000) and then the jump to my bootloader works. Then I let my bootloader jump back (FIRMWARE_START_ADDRESS = 0x08000000) to the AN2557 bootloader and that also worked. But when I jump for a second time to my bootloader it doesn't work anymore. I've added the vector redirection to both projects and it still doesn't work.

My bootloader is written in c++. Most of my hardware is managed by singleton classes. Is something not initialized properly (statics)?

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  • Hi Bjorn,

    I have developed a similar library starting from the same application note, but I approached it in a slightly different way.

    The loader is located at 0x08000000 and just jumps (if there is valid code) at a given location. Actually it can jump at several locations.

    I have placed an updater at UPDTADDR = 0x08000000+OFFSETUPDT and my application at APPLADDR = 0x08000000+OFFSETAPPL. They both relocate the vector table at the proper address.

    In normal cases the loader jumps to APPLADDR.

    But when I need to update the code of the application I force the bootloader to jump to UPDTADDR and I do whatever I need (in your case use an USART to communicate, in my case ethernet). At the end of the operation, I dont jump to any location but I prefer to force a reset passing again from the loader.

    The reason is that if I jumped I should deinit every HW peripheral, every ISR etc.

    You can use code as in the following to jump or to restart:

    
    static void s_jump_to(uint32_t appaddr)
    {
        volatile uint32_t jumpaddr;
        void (*app_fn)(void) = NULL;
    
        // prepare jump address
        jumpaddr = *(__IO uint32_t*) (appaddr + 4);
        // prepare jumping function
        app_fn = (void (*)(void)) jumpaddr;
        // initialize user application's stack pointer
        __set_MSP(*(__IO uint32_t*) appaddr);
        // jump.
        app_fn();
    }
    
    extern void system_restart(void)
    {
        ...
    
        // disable irqs .... is it really necessary?
        __disable_irq();
    
        // restart system
        NVIC_SystemReset();
    
        // should be never in here
        assert(0);
    }
    
    
    

    I hope it can help.

    Reagrds, Marco.

Reply
  • Hi Bjorn,

    I have developed a similar library starting from the same application note, but I approached it in a slightly different way.

    The loader is located at 0x08000000 and just jumps (if there is valid code) at a given location. Actually it can jump at several locations.

    I have placed an updater at UPDTADDR = 0x08000000+OFFSETUPDT and my application at APPLADDR = 0x08000000+OFFSETAPPL. They both relocate the vector table at the proper address.

    In normal cases the loader jumps to APPLADDR.

    But when I need to update the code of the application I force the bootloader to jump to UPDTADDR and I do whatever I need (in your case use an USART to communicate, in my case ethernet). At the end of the operation, I dont jump to any location but I prefer to force a reset passing again from the loader.

    The reason is that if I jumped I should deinit every HW peripheral, every ISR etc.

    You can use code as in the following to jump or to restart:

    
    static void s_jump_to(uint32_t appaddr)
    {
        volatile uint32_t jumpaddr;
        void (*app_fn)(void) = NULL;
    
        // prepare jump address
        jumpaddr = *(__IO uint32_t*) (appaddr + 4);
        // prepare jumping function
        app_fn = (void (*)(void)) jumpaddr;
        // initialize user application's stack pointer
        __set_MSP(*(__IO uint32_t*) appaddr);
        // jump.
        app_fn();
    }
    
    extern void system_restart(void)
    {
        ...
    
        // disable irqs .... is it really necessary?
        __disable_irq();
    
        // restart system
        NVIC_SystemReset();
    
        // should be never in here
        assert(0);
    }
    
    
    

    I hope it can help.

    Reagrds, Marco.

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