RE: DK52 Bootloader/Reset. Stuck in Bootloader mode, won't reset

gary — Mon, 10 Jan 2022 15:32:58 GMT

For anyone else just starting with Nordic - The answer is that the procedure is not documented in the DK manual, or anywhere else I can find, but apparently this is the normal way this procedure works. First, the rest button doesn't do anything if the power to the board is not cycled.

Second, using the reset button while powering the DK doesn't seem to do anything except delete the existing bootloader file. If you did this because you were trying to program the DK with something other than Segger and the download hung-up and some tutorial(maybe for another Nordic device) you read said that you need to push the reset button when downloading a new program, that tutorial doesn't apply here, the DK board doesn't work like that. If the download got hung-up it's a different reason, maybe you are working in a file path that has a space in it? C compilers don't like that.

Anyway, now, you have to get a new .bin file from the Nordic website and copy the .bin file into the root directory of the DK52 that now shows up as a drive named BOOTLOADER. There will be other files and a folder, but those can be ignored.

After Copying the the .bin file onto the BOOTLOADER drive, cycle power to the DK board and it wshould now show up as a JLINK.

The file vesion I used is:

j-link-ob-sam3u128-v2-nordicsemi-170724.bin

I got it form this link.

https://www.nordicsemi.com/Products/Development-hardware/nRF52-DK/Download?lang=en#infotabs

RE: DK52 Bootloader/Reset. Stuck in Bootloader mode, won't reset

Turbo J — Sun, 09 Jan 2022 11:13:26 GMT

The JLink bootloader wlll always show up as a drive letter, and you must put the correct Jlink firmware file on it.

Remember that this is the bootloader from the debugger chip and not the NRF52x.

And yes, you must copy this file every time you powered the DK with the reset button pressed. This is the firmware update procedure for the debugger chip running the JLink protcol, which then talks (via SWD and UART) to the NRF52x chip.

The file can be found under "Interface MCU firmware" in the downloads for the DK52.