nRF52-DK Non-responsive

RE: nRF52-DK Non-responsive

Emlyn — Wed, 05 Aug 2026 18:33:05 GMT

This implies that you can see the board on USB.
It is not connectable.

RE: nRF52-DK Non-responsive

Emlyn — Wed, 05 Aug 2026 15:58:58 GMT

5.18V on the bottom pads of the two left most components (R/C) and 0V on the bottom of the right component of the three (the other cap).

Resistor is measuring 2ohms,
Top pads of the two caps measure zero

So:

5.18 0 0
| | |

5.18 5.18 0

A full schematic would be helpful to diagnose.
The P1 VDDs have 3v reading

RE: nRF52-DK Non-responsive

PjGlasso — Wed, 05 Aug 2026 15:54:30 GMT

Hi there,

So in the devices view in NRF_SDK in VB, there is a " RECOVER BOARD" Did you try that First ?

It can happen that some code or issue can corrupt the board , Clicking recover will return it to normal.

DO you know where that option is ?

HTH

GL :-) PJ:v:

RE: nRF52-DK Non-responsive

Asbjørn — Wed, 05 Aug 2026 11:16:02 GMT

Hi Emlyn,

I should have asked you in a previous reply, but what are you measuring on the VBUS input to the ODB nRF5340?

See the red arrow for the location of the R9, C35 and C36 cap on the VBUS input. When the cable and everything is plugged in, what voltage are you measuring there on these three components?

Best regards

Asbjørn

RE: nRF52-DK Non-responsive

Emlyn — Tue, 04 Aug 2026 13:55:37 GMT

Hello Asbjørn,

No, I did not try to reprogram the ODB. I don't have a J-Link other than this broken board.
My questions down this path were whether it could be recovered this way though another J-link, but that seems not to be the case.

I was running a BTle app on the application processor, using softdevice 132.
RTT viewer 9.62
nRF Connect Desktop 5.3.2, programmer 4.8.0
Windows 11, 64 bit

RE: nRF52-DK Non-responsive

Asbjørn — Tue, 04 Aug 2026 09:52:59 GMT

Hello Emlyn,

Thank you for the picture of the kit. It's not a common issue, but with the number of kits we do have in the market, sometimes things do go wrong. Unfortunately it can come down to board switches set incorrectly (hence the picture request), often it is related to USB port and cable along with non-windows environment. Some then try to peel of the sticker and re-program the On Board Debugger. As indicated by Paal below here as well.

Did you try to reprogram the ODB on the kit through the JTAG header under the sticker?
The behaviour you're describing does indicate that the FW on the nRF5340 ODB has been changed and this isn't something we have a clear path understand on how it could be. What sort of OS environment are you working with? What versions of Segger SW and tools are you using?

Best regards

Asbjørn

RE: nRF52-DK Non-responsive

Emlyn — Mon, 03 Aug 2026 21:26:31 GMT

The board has not had any switches / cutstraps changed. Is there something I should / could try here?

It was happy as a clam until it wasn't - but I was seeing the BTle connection for a bit with my software, flashed via the debug chip and using RTT.

I don't see how ESD could have happened with mat and wrist strap- also never had an issue here previously.

I've tried a few different cables and PCs and the behaviour is the same- on insertion of the cable, there's a brief flash on LED5 and then off.

RE: nRF52-DK Non-responsive

PaKa — Mon, 03 Aug 2026 20:48:15 GMT

The first case is for programming the nRF52 on the board, that is still OK with the new board. What you can't do is program the nRF5340 debugger chip.

The second looks to be is how to recover the nRF52 if you have locked it and want to reprogram it, again it's for the nRF52 so OK.

We do not see cases where there is a need to reprogram the nRF5340 on the DKs, the issues are "always" something else that has happened. The common issues are incorrectly set switches, USB cable, PC side issues (both USB HW and driver SW), mechanical damage to the DK, USB connector. No chance of ESD damage?

Couldn't see any but have you by chance modifed any of the cutstraps? Not uncommon to see questions about non-functional boards where this is forgotten :-)

RE: nRF52-DK Non-responsive

Emlyn — Mon, 03 Aug 2026 14:37:50 GMT

Q1 - it's the nRF52-DK v3.0.5

Q2: I _think_ that it stopped working during a development session with a BTle app using softdevice 132. I can't be 100% sure but it was working fine for a while. I was not actively debugging - just running the firmware on the application processor.

Is this situation common?
[nRF52DK] Unable to Recover due to Error -21
recover nrf52 DK

RE: nRF52-DK Non-responsive

Emlyn — Mon, 03 Aug 2026 14:34:57 GMT

The device appears to be bricked already. Are you saying that with the new boards, there's no way to re-flash the firmware if the device is non-responsive over USB?

Does this only apply to the app processor?
devzone.nordicsemi.com/.../program-a-nrf52-dk-with-another-nrf52-dk

There's also random questionable things like this too: https://gist.github.com/cszuo/22a08e3263fcfd397bf9bd91ce5168b0

RE: nRF52-DK Non-responsive

Asbjørn — Mon, 03 Aug 2026 12:55:18 GMT

Hi again Emlyn,

Q1: Could you upload a picture of the board you are having issues with?

Q2: What did you debug when the board stopped working? Were you running something actively on it or was the board idling somehow? You say you were running a debugging session when it stopped responding. What and how were you debugging?

Best regards

Asbjørn

RE: nRF52-DK Non-responsive

PaKa — Mon, 03 Aug 2026 07:47:25 GMT

Note: If you attach a j-link to reprogram the On Board Debugger (nRF5340) to the pins under the label then you will brick the DK and it won't be recoverable so that is a hard NO.

Normally these kind of issues is caused by USB connectivity issues so check cable and connector on the DK.

RE: nRF52-DK Non-responsive

Emlyn — Sun, 02 Aug 2026 16:10:17 GMT

This is the new DK. It can be flashed with a J-link to the pins under the label, but I don't have a J-link handy.

RE: nRF52-DK Non-responsive

Turbo J — Sun, 02 Aug 2026 07:58:33 GMT

Old DK hardware with the ST debug MCU chip? Hold reset when powering up, put interface MCU firmware on the drive that appears. You need to do this every time you held reset down when powering up, its quite annoying.

The newer HW revision with the NRF5340 debug MCU has a different upgrade procedure IIRC.

RE: nRF52-DK Non-responsive

Emlyn — Fri, 31 Jul 2026 13:41:10 GMT

Q1: Only the USB was plugged in.
Q2: Yes, also looked at voltages. All rails are at expected values and looks like the the MCU is non-responsive.
Q3: USB port is fine; other devices work, nRF52-DK is non-responsive in other ports.

Any way that the application processor software could affect the MCU on the board?
LED5 lights _very_ briefly on power up but remains off otherwise.

RE: nRF52-DK Non-responsive

Asbjørn — Fri, 31 Jul 2026 10:32:48 GMT

Hello Emlyn,

Q1: Did you have something external connected to the DK at the time?

Q2: I assume you've checked the power switch, but are you able to check the voltage on the DK? Since LED5 isn't lightening up, it indicates that there isn't power coming to the board.

Q3: USB connection, is the USB port ok? Does it work with other boards?

Best regards

Asbjørn