How to fix the voltage mismatch between VTref and VDD on the target board?

[Pony]

Hi everyone. I’m currently working on a custom board based on the nRF5340, but I’m unable to connect to the board when trying to flash it via the SWD interface using J-Link. Here is the error message from my SDK:

Error: One or more device info tasks failed:

302005664: Device error: A timeout occurred while handling debug power: Timed out trying to power sys and debug region

(Generic)

When troubleshooting with J-Link Commander, I got the following output:

J-Link>st

VTref=1.673V

ITarget=0mA

TCK=1 TDI=0 TDO=0 TMS=0 TRES=1 TRST=?

Supported target interface speeds:

• 96 MHz/n, (n>=24). => 4000kHz, 3840kHz, 3692kHz, ...

However, I measured 3.1V on the SWD VDD pin with a multimeter, and the main chip power supply seems normal.

Also, because I cannot connect, I cannot try the nrfjprog --recover command suggested by AI.

Does anyone have any good solutions?

[Kazi Afroza Sultana]

Hello,

Probably If VTref is not correctly connected to your board's VDD. As you can see 3.1V at VDD but on the Jlink commandar output Vterf is 1.6V. Can you check with different cable?

[Pony]

Thank you for advice! I've checked the board and it seems that I connected the SWD pins incorrectly.

[Kazi Afroza Sultana]

You have the same voltage for VDD and Vterf?