RE: DFU over serial uart about nrf52840

Vidar Berg — Wed, 30 Sep 2020 07:19:31 GMT

Hello,

It should be pretty straight forward to implement this mechanism in the application. The code may looks something like this:

#define BOOTLOADER_DFU_GPREGRET_MASK            (0xF8)      /**< Mask for GPGPREGRET bits used for the magic pattern written to GPREGRET register to signal between main app and DFU. */
#define BOOTLOADER_DFU_GPREGRET                 (0xB0)      /**< Magic pattern written to GPREGRET register to signal between main app and DFU. The 3 lower bits are assumed to be used for signalling purposes.*/
#define BOOTLOADER_DFU_START_BIT_MASK           (0x01)      /**< Bit mask to signal from main application to enter DFU mode using a buttonless service. */

#define BOOTLOADER_DFU_START    (BOOTLOADER_DFU_GPREGRET | BOOTLOADER_DFU_START_BIT_MASK)      /**< Magic number to signal that bootloader should enter DFU mode because of signal from Buttonless DFU in main app.*/


/* Call this when the custom AT command has been received */
void dfu_mode_enter(void)
{
    
    err_code = sd_power_gpregret_clr(0, 0xffffffff);
    VERIFY_SUCCESS(err_code);
    
    /* Bootloader will check this GPREGRET register on startup to 
       determine if it should enter DFU mode or not */
    err_code = sd_power_gpregret_set(0, BOOTLOADER_DFU_START);
    VERIFY_SUCCESS(err_code);
    
    NVIC_SystemReset();
}