Blinky doesn't work on nRF52840-dongle via J-Link

[mlac]

Hi there,

The blinky sample worked fine on the nRF52840-dongle when programmed via the stock bootloader, but I need to flash it via J-Link to reproduce an issue.

When flashing blinky via J-Link, the LED doesn't blink.

I guess I have to tweak the sample in some way. I tried to use MCUboot by adding CONFIG_BOOTLOADER_MCUBOOT=y and CONFIG_PM_PARTITION_SIZE_MCUBOOT=0x40000 in mcuboot.conf to no avail.

Thanks in advance for your help!

- Laci

[Felix Shih]

try this

devzone.nordicsemi.com/.../how-to-generate-nrf52840-dongle-hex-file-with-using-external-j-link-to-program-and-run-directly

[mlac]

I've added the suggested Kconfig options to prj.conf which now contains:

CONFIG_FLASH_LOAD_OFFSET=0x0
CONFIG_BOARD_HAS_NRF5_BOOTLOADER=n

Then, I did a pristine build, and the boot partition has not changed in build/zephyr/zephyr.dts:

					boot_partition: partition@0 {
						label = "mcuboot";
						reg = < 0x0 0x10000 >;
					};

The issue persists.

[Felix Shih]

You should check zephyr.hex, zephyr.dts mcuboot address won't change.

The .hex file first line should be

:10000000009B00204D57010053E8020039570100C2

[mlac]

It turns out the LED started to blink after I rebooted the board with its reset button.

Why do I have to reset it after flashing it?

0882.zephyr.hex

[JONATHAN LL]

You should always do a reset either soft or hard after flashing new firmware on the device. 

Not sure what is the reason why, but doing a reset will make sure that the device is out of debug mode and might also related to some security thing. 

So always good to do a reset to make sure the applications starts correctly. 

Regards,
Jonathan