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Can I use a nucleo64 st-link to program and power an external MCU?

Associate III


I have a NUCLEO-F446RE board, lots of homemade boards with little MCUs (STM32G030F6, STM32F103C6, ...), some blue pills and programmers. Only the first ones I bought has an original chip. The other blue pills and programmers, the vendor lies and send me counterfeited pieces ☹️


I need to use the ST-LINK of the NUCLEO for my homemade boards, but I don't see any power pin on the SWD connector. Document UM1724, page 19, says Pin 1 VDD_Target, VDD from application.

Looking the schematic, seems that pin does nothing. Only connected to ground thru R10, 10 kOhm resistor. R9 is not present.

I'm plan to connect pin1 to 3V3_ST_LINK and will power my MCU with only one connector. The 150 mA that the LD3985M33R can supply is sufficient for the ST_LINK MCU and a little MCU to program.


Does anyone thing I'm wrong?



ST Employee

Hello @xisco and welcome back to the ST Community 😊.

I suggest you to take a look at this post. It could be helpful on your case.

Best Regards.


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