Hello, I tried your second suggestion and it didn't work. I used a multimeter to check the voltage of the SWDIO and SWDCLK signals, I get 0.16V and 0.5V respectively. Does this tell you something?
I tried connecting the J-link EDU mini to my target board via SWD and it can seem to connect. The target board is a custom PCB which features the STM32F401RDT6 microcontroller. I connect the SWDIO and SWDCLK pins together, also the ground and VRef pin. This is what I get as the output : Output SEGGER J-Link Commander V7.94c (Compiled Jan 3 2024 15:17:49) DLL version V7.94c, compiled Jan 3 2024 15:17:37 Connecting to J-Link via USB...O.K. Firmware: J-Link EDU Mini V1 compiled Dec 13 2023 14:36:33…