NRF52840 Donlge - JLink Programming

[jibba]

Hi

I have a coupe of dongles working on a project. While validating the board, i notice a strange behavior:

I have the dongles in factory reset (MBR at start, the Bootloader at the end of flash), and i took a backup of this so i can restore dongles anytime.

So what i have now is a blinky program, based on MbedOS. There i modified the linker script so Flash_Start = 0x1000 and Ram_Start=0x20000008 (copied over from the OT-CLI example from the dongle).

So when i now go ahead and program my blinky app (hex) with the NrfConnect-Programmer, it works just fine. Blinky works, or if reset is pressed, i go into DFU bootloader mode.
If i do the same but program the blinky app directly with JFlash from the Segger tools, nothing works.

So i went ahead and read both chips and compared them.

See both files here for a text compare (https://we.tl/t-SqAry7eaAh)

Why is somehow my blinky app (after 0x1000 in flash) looking different? do you guys somewhat do more than just flash a hex file during nrfconnect-programming?
i use this method a lot any other Cortex-M chip with more than 1 binary in its flash storage, i know what im doing. so right now im lost with the nordic chips, which somewhat behalve strangely.

Please help me out here, with a detailed explaination.

thank you

[jibba]

Ok. Here is the hexfile i flashed (https://we.tl/t-VuXnDaqxy8)

#include "mbed.h"

int main()
{
    DigitalOut led1(P0_6,  1);
    DigitalOut led2(P0_8,  1);
    DigitalOut led3(P1_9,  1);
    DigitalOut led4(P0_12, 1);

    while (true)
    {
        led1.write(0);
        ThisThread::sleep_for(10);
        led1.write(1);
        ThisThread::sleep_for(10);

        led2.write(0);
        ThisThread::sleep_for(10);
        led2.write(1);
        ThisThread::sleep_for(10);

        led3.write(0);
        ThisThread::sleep_for(10);
        led3.write(1);
        ThisThread::sleep_for(10);

        led4.write(0);
        ThisThread::sleep_for(10);
        led4.write(1);
        ThisThread::sleep_for(10);
    }
}

#define MBED_APP_START 0x1000
#define MBED_APP_SIZE 0xDB000
#define MBED_RAM_START 0x20000008
#define MBED_RAM_SIZE 0x3FFF8
#define MBED_BOOT_STACK_SIZE 0x800
#define MBED_RAM0_START MBED_RAM_START
#define MBED_RAM0_SIZE  0x100

#define MBED_CRASH_REPORT_RAM_START (MBED_RAM0_START + MBED_RAM0_SIZE)
#define MBED_CRASH_REPORT_RAM_SIZE  0x100

#define MBED_RAM1_START (MBED_CRASH_REPORT_RAM_START + MBED_CRASH_REPORT_RAM_SIZE)
#define MBED_RAM1_SIZE  (MBED_RAM_SIZE - (MBED_RAM0_SIZE + MBED_CRASH_REPORT_RAM_SIZE))

MEMORY
{
  FLASH (rx)     : ORIGIN = MBED_APP_START, LENGTH = MBED_APP_SIZE
  RAM_NVIC (rwx) : ORIGIN = MBED_RAM0_START, LENGTH = MBED_RAM0_SIZE
  RAM_CRASH_DATA (rwx) : ORIGIN = MBED_CRASH_REPORT_RAM_START, LENGTH = MBED_CRASH_REPORT_RAM_SIZE
  RAM (rwx)      : ORIGIN = MBED_RAM1_START, LENGTH = MBED_RAM1_SIZE
}

[jibba]

Hi Jorgen

Is this ticket still in process or do you need more information ?

Thank you