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

[eng1n88r]

I'm having the similar issue.

I'm using nRF52840DK (PCA10056 3.0.0 2023.3) and XIAO nRF52840 Sense with Expansion Board as target.

On the expansion board I use first column pins (SWCLK, SWDIO, 3V3, GND) that are connected to the P20 on DK (SWDCLK, SWDIO, VDD nRF, P1.GND). 

When I switch DK to ON position, XIAO and Expansion board are powering up. I'm using VSCode and I see only DK board and during flash DK board is getting flashed. 

What am I doing wrong?

[Sigurd Hellesvik]

Did you remember to connect SWD0_SEL to Ground?

[eng1n88r]

I tried both variants and no success.

[PaKa]

Check that you comply with this one (the DK user guide for the nRF52840 hasn't been updated yet). https://infocenter.nordicsemi.com/topic/ug_nrf52832_dk/UG/dk/ext_programming_support_P20.html. The nRF52840 DK has the same interface for programming external targets as the nRF52 DK.

[Sigurd Hellesvik]

eng1n88r said:

to the Ground on the target board or on DK itself?

When programming an external board, both boards must share Ground.
I suggest that you start by connecting the Grounds together

[eng1n88r]

I think I mentioned in my question that ground on both boards is linked. Sorry, maybe I was not clear enough.

[eng1n88r]

Thank you for the link! The layout or P20 on DK is a bit different, and I believe there is where some confusion coming from:



There is no VTG.

[PaKa]

Sorry, didn't notice the guys didn't use the same naming on all the nets. The VTG pin on the nRF52 DK is still the same as the SWD SEL functionality wise, all the DKs use the same code for the debugger so functionality will be the same for the same OBD.

We did a change in OBD (On Board Debugger aka JLINK) device between the 2.x version and the 3.x version and that changed the functionality on some of the pins. If you follow the user manuals to the letter it should still work but if you don't mount all the lines as instructed (like you did) then you can get problems with the programming of external targets.

[eng1n88r]

Thank you so much for clarifying that! I was finally able to flash target board. Documentation not being up to date didn't make it easy.

I would also really appreciate if you could point me to where I could find any information about debugging code on target board. I tried to do it via VS Code, but without success. I created build configuration optimized for debugging. I'm able to flash the board via VS Code. But when I try to debug (or attach debugger to target) I'm getting something like this:

[Sigurd Hellesvik]

If you can program the board, debugging should generally not be an issue.

However, this is kindof a new issue you are facing here.
To help us keep DevZone tidy, could you open a new ticket for the debugging issue?