Voltage problem on VDD pin on SWD connector.

[anonymous.8]

It's my first design with a STM32 MCU. I want to program a MCU on my custom board with the ST-LINK but when I try with STM32 ST-LINK Utility the connection doesn't work. The STM isn't recognized. When I measure VCC signal on the connector SWD I have only 0.79 V instead of 3.3V.

Someone can explain me what is the problem or what I'm doing wrong ?

[Tesla DeLorean]

Review the manual for the stand-alone ST-LINK. It expects it's buffers to be powered by VTarget from your board.