SWD connection with TC2050-IDC-NL 10-Pin No-Legs Cable

RE: SWD connection with TC2050-IDC-NL 10-Pin No-Legs Cable

kc9999 — Tue, 26 Aug 2025 17:51:31 GMT

Transferred the ticket a to private ticket: Case ID: 350478 for all the schematic design

RE: SWD connection with TC2050-IDC-NL 10-Pin No-Legs Cable

Turbo J — Tue, 26 Aug 2025 08:34:00 GMT

You can try a very slow SWD clock, 500 kHz sometimes works better with bad cabling.

I spot 2 big issues: Reset pin must be accessible from the debug port (or at least from a test point), and the debug interface must have access to the actual target voltage (VDD) from the nordic chip.

If you supplied 5V to the debug pins, you might have grilled the MCU. The pins do not tolerate 5V levels.

Edit: It would also surprise me if your antenna setup worked for more than 5-10m range. We are missing an important layer but that HF signal does not look properly routed to me. Won't affect the debug connection yet and I don't design 2.4 GHz PCBs - we use 3rd party modules here.

RE: SWD connection with TC2050-IDC-NL 10-Pin No-Legs Cable

kc9999 — Mon, 25 Aug 2025 21:03:05 GMT

Hi Kazi,

I’ve double-checked all the wiring, and everything should be correctly wired. This project is meant to downsize our previous prototype, which is why we’re using the TC2050, and we’ve never encountered this kind of issue before.

The log from Jlink commander:

and our schematics:

Thank you,

Kevin

RE: SWD connection with TC2050-IDC-NL 10-Pin No-Legs Cable

Kazi Afroza Sultana — Mon, 25 Aug 2025 13:03:52 GMT

Hello Kevin,

The error you are seeing seems related to the connection error or voltage mismatch between the debugger and the target board. Maybe the wire is connected wrong way. I agree with Fischer's comment.

You need to check if the target device is powered and that VTref is present at the debugger. To identify the correct voltage, you can use Jlink commander tools. For example, it will show the VTref volatge in follwing way.

If the target is not powered or VTref is missing, you will get this error —Failed to write DebugPort register 2: Unknown Error in J-Link DLL (error code =-1).

Can look at this case (22) Flashing nRF52840 SOC in nRF52840 DK using External J-link, without using interface MCU (so, using nRF only mode) - Nordic Q&A - Nordic DevZone - Nordic DevZone

You can try to use a different PC or reinstall the jlink driver.

RE: SWD connection with TC2050-IDC-NL 10-Pin No-Legs Cable

Turbo J — Sat, 23 Aug 2025 05:43:37 GMT

Verify ALL of the basics (voltages etc) and that the wirering was done as expected.

We can't see your schematic and layout here, and that is required in order to debug debugger stuff.

The nordic command line tools don't really provide helpful error messages, I found using Jlink commander directly yields better results debugging wirering issues with the debug port. There you can see what voltage the debugger sees from the target.

Some Nordic MCUs want the reset pin wired on the debug connector - there are not enough wires here for that to happen.