Jumping to Bootloader from the Application

[rabiaasl]

How can I jump to the bootloader from the application without anything BLE related. Possibly through a botton?

I'm on the newest SDK v11.

[bjorn-spockeli]

In order to jump to the bootloader , you have to add this define in your application project

#define BOOTLOADER_DFU_START 0xB1

and call the following functions when the button is pressed:

if (button_is_pressed)

{
    //  Write to the the GPREGRET REGISTER and reset the chip

   //You can use the sd_-functions 

    err_code = sd_power_gpregret_set(BOOTLOADER_DFU_START);

    APP_ERROR_CHECK(err_code);

    sd_nvic_SystemReset();   


   //OR set the register directly and then call NVIC_SystemReset(); 

    NRF_POWER->GPREGRET = BOOTLOADER_DFU_START;

    NVIC_SystemReset();
}

In the bootloader you have to remove the init_softdevice check in ble_stack_init(), i.e.

//if (init_softdevice)

//{
    err_code = sd_mbr_command(&com);

    APP_ERROR_CHECK(err_code);
//}

-Bjørn

[rabiaasl]

Are there any restrictions on how many times you can read/write to this register? Or what you set it as? After setting it does it always have to be followed by a reset? What if you want to communicate different reasons why a reset occurred using this register? Can you set it to values of your choice?