Connecting SWD Pins from nRF52840 to Custom Board - Need Assistance

[EMPROTEK]

Hello Nordic DevZone,

I am working with an nRF52840 (from the nRF52840-DK) and I am in the process of connecting the SWD interface to my custom board. I have the following pins available:

• SWDIO
• SWDCLK
• RESET
• GND
• SWDOSEL (which I understand may not be necessary for basic SWD debugging)

Additionally, I need to confirm if it is required to short VDD and REF on the nRF52840-DK board to enable proper operation. I would appreciate clarification on this as well.

I would like to confirm the proper connections to my custom board and ask for clarification on the following:

1. Do I need to connect SWDOSEL to anything specific, or can it be left unconnected?
2. Should I connect RESET from the nRF52840 to my custom board's reset line, or is there an alternative method?
3. Are there any other important considerations when connecting the SWD interface to my custom board?
4. Is it necessary to short VDD and REF on the nRF52840-DK for this connection to work properly?

Thank you for your help!

[runsiv]

Hi

1. No you don't need to connect it

2. Yes

3. You need to use the same voltage level on both devices

4. Yes

In short you should follow what described in the debug out

Regards

Runar

[PaKa]

Note: the documentation above is for the older DKs with the larger debugger. If you have a newer board (3.x.x) then you should use the connections from https://docs.nordicsemi.com/bundle/ug_nrf52832_dk/page/UG/dk/ext_programming_support_P19.html. Unfortunately the nRF52840 DK documentation hasn't been updated but the setup is the same as on the nRF52832 DK.

[EMPROTEK]

THANK Runar