nRF 52840DK debug out on board version 3.0.0 not working

[hector77]

Hi there, 

We have recently purchase some more nrf52840DK to develop and program custom boards based on the same SoC. The new DK (from Digikey) have the following sticker
PCA10056
3.0.0
2022.20

When we use them to program other nRF52840 SoC, it looks like the external board is not recognized.

With some other earlier version of the nrf52840DK (2.0.2, 2021.43) everything was working fine. Could you please help us understanding what possible issues might be at stake ?

More info: I have also tried to pull down the GND Detect as mentioned here:  Using Debug Out (p19) to program 3rd Party nrf52840/nrf52810 boards with issues , but when looking at the DK 3.0.0, on Debug Out P20 connector, it looks like the GND Detect pin is no longer present (at leas the label is not). 

Many thanks for your help.

Best regards, 

H

[hector77]

Here is the picture of one of the DK.

Many thanks for your help.

H

[Sigurd Hellesvik]

Hi H,

We have not found out what your issue could be yet, so I will continue asking some questions, which might help us get to the bottom of this:

I assume you have external power to your custom board?

Which voltage do the custom board run at?

Just to be sure: Are you connecting your Tag Connect cable to P19 (Debug Out)?

You mentioned P20. Could you explain some more if you connect to it and how?

Regards,
Sigurd Hellesvik

[hector77]

Yes we have an external board self-powered at 2.5V, not 3V3 though but this did not seem to be an issue with the previous DK.
(I have measured 2.54V on the Debug Out connector on the DK)

We use only P19 Debug Out (I was just mentioning P20 with reference to the test we tried briefly on that connector too)

Regards, 

H

[Sigurd Hellesvik]

Hi

hector77 said:

we have an external board self-powered at 2.5V,

This will be it then.
Our chips require the same voltage level in the debugger as in the chip.

And our nRF52840 Development Kit(DK) only supports programming devices at 3V.
So even if it worked for the 2.0.2 DK, we can not guarantee that it should work for 3.0.0.

I recommend that you acquire an external debugger which supports variable voltages to program your custom boards.
See https://www.segger.com/products/debug-probes/j-link/

Regards,
Sigurd Hellesvik

[hector77]

Dear Sigurd, 

Many thanks for the clarification, we will follow your recommendation then.

Kind regards, 

H