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

[Sigurd Hellesvik]

Hi H,

If you want to have a closer look at the differences between version of the Developement Kit, have a look at the hardware schematics in the nRF52840DK product page -> downloads.

Can you create a simple drawing on how you have connected the custom board to the Developement Kit, so that I can double check it?

Regards,
Sigurd Hellesvik

[hector77]

Hi Sigurd, 

Many thanks for the reply. To connect the custom board to the Dev Kit we use Tag-Connect cables. The reference for the Cortex compatible version we use is here: 

https://www.tag-connect.com/product/tc2030-ctx-nl-6-pin-no-legs-cable-with-10-pin-micro-connector-for-cortex-processors

The datasheet can be found here: https://www.tag-connect.com/wp-content/uploads/bsk-pdf-manager/TC2030-CTX_1.pdf

From the datasheets, connection between the boards is:

6pin Custom board -> Dev Kit
----------------------------------------
1 VCC                     -> 1 VCC
2 SWDIO                -> 2 SWDIO
3 nReset                 -> 10 nReset
4 SWDCLK             -> 4 SWDCLK
5 GND                    -> 3, 5, 9 GND and also GND Detect (according to Tag-Connect datasheet)
6 SWO                   -> 6 SWO

Best regards,

H

[Sigurd Hellesvik]

Hi H,

Can you double-check with a multi-meter that when the cable is connected, all Developement Kit GND pins (3,5 and 9) are actually connected to GND of the Custom Board?

Regards,
Sigurd Hellesvik

[Sigurd Hellesvik]

Hi H,

In addition, could you send a picture of the nRF52840DK 3.0.0. It might be useful to have a look at it.

Regards,
Sigurd Hellesvik

[hector77]

Hi Sigurd, 

I can confirm the signal test between the Dev Kit Debug Out pins 3, 5, 9 and the GND of the custom board is ok.

H