Unable to flash custom nRF52840 board using nRF52840dk - Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown error in the J-Link DLL (error code =-1)).

[LonnieB]

I am using nRF Connect SDK 3.2.1 and Toolchain 3.2.1. The hardware I am using is the nRF52840DK and a custom board with the Raytac MDBT50Q-P1MV2 - which contains the nRF52840. I created a custom board in the SDK and built a program that blinks an onboard LED on the custom board. The program builds without error, but when I try to flash the code to the custom board I get the following error - Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown error in the J-Link DLL (error code =-1)). I saw a similar question 4 months ago, but no solution was ever obtained (or if it was the developer never replied). My custom board is powered by a 3.3V LDO regulator that is powered by a 3.8V power supply. The SWD setup uses a 10 pin connector with with pinout: 1: VCC= 3.3V supplied from LDO regulator, 2: SWDIO, 3: GND, 4: SWCLK, 5: GND, 6:SWO, 7: GND, 8: N/C, 9: GND. 10: nRESET. I use a ribbon cable with connectors purchased from Adafruit for the J-Link edu mini to connect my board to the DK Debug Out port P19. When I power my board and connect it to the DK, I see the following voltages on some pins I can access: On SCL and SDA pins I see 2.3V; On SDIO I see 3V. On SWCLK I see 0V. (One odd thing is if I power my board and do not connect it to the DK, I see a 1.6V, 260uS pulse every 34mS on the SWDIO line - so about 30Hz)

I designed the board (based on the Adafruit nRF52840 feather and assembled it myself. This is the first time I've used the Raytac module, so I don't know exactly how to prove it is working correctly before flashing it. I have attached a picture of the flashing setup - my board and the SDK with ribbon connector, and a picture of my schematic for reference. Here is the text from the Output and Terminal windows in nRF Connect extension for VS Code: 

Output
[13:47:34] build --build-dir c:/myfw/protoboard/button/build --domain button
[13:47:36] Success.
[13:47:40] flash -d c:\myfw\protoboard\button\build --domain button --dev-id 1050257059
[13:47:42] Failure (code 1).



Terminal

 *  Executing task: nRF Connect: Build [incremental]: button/build/button

Building button
west build --build-dir c:/myfw/protoboard/button/build --domain button
-- west build: building domain(s): button
ninja: no work to do.
 *  Terminal will be reused by tasks, press any key to close it.

 *  Executing task: nRF Connect: Flash: button/build/button

Flashing button to nRF52840 DK
west flash -d c:\myfw\protoboard\button\build --domain button --dev-id 1050257059
-- west flash: rebuilding
[0/5] Performing build step for 'button'
ninja: no work to do.
[4/5] cmd.exe /C "cd /D C:\myfw\protoboard\button\build\_sysbuild && C:\ncs\toolchains\66cdf9b75e\opt\bin\cmake.exe -E true"
-- west flash: using runner nrfutil
-- runners.nrfutil: reset after flashing requested
-- runners.nrfutil: Flashing file: C:\myfw\protoboard\button\build\merged.hex
-- runners.nrfutil: Connecting to probe
Error: One or more batch tasks failed:
 * 1050257059: Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown Error in J-Link DLL (error code =-1)).
   
   This might indicate that the debug port is unavailable. Please double-check device power sFATAL ERROR: command exited with status 1: nrfutil --json device x-execute-batch --batch-path 'C:\myfw\protoboard\button\build\button\zephyr\generated_nrfutil_batch.json' --serial-number 1050257059

 *  The terminal process terminated with exit code: 1.
 *  Terminal will be reused by tasks, press any key to close it. 

Appreciate your expert review and advice,

Lonnie

[Simonr]

Hi Lonnie

This sounds strange. The setup looks correct here. A common mistake is that the 10-pin cable is connected the wrong way if you don't have the 10 pin header with plastic to make sure it can only be mounted one way.

If not, are you able to set the custom board voltage to 3.0V, since that is the DK's supported voltage by default. https://docs.nordicsemi.com/bundle/ug_nrf52840_dk/page/UG/dk/ext_programming_support_P19.html 

Is this the full schematics of your board? Which of the headers in the schematics is the 10 pin header?

Best regards,

Simon

[LonnieB]

Simon,

Thanks for the reply. I copied much of the design from the nrf52840 feather, including the connectors and their pinouts, and I checked voltages while my board was connected to the DK - and they look correct - so I think the 10-pin cable is connected correctly. The schematic attached is the full schematic (it is a test board with access to I2C and some GPIO pins that I can use to test code and various sensors before I spin a production board) and J2 is the 10 pin header - it is center bottom of the schematic. 

Powering my board from a 3.0V (vs 3V3) supply is probably doable (I'd have to connect my power supply directly to the VCC rail of the board without going through the regulator, but if it is threshold levels that you are concerned about, I doubt that my board wouldn't recognize a 3V signal. I can try if you have doubts.

Thanks again,

Lonnie