2025-05-13 1:05 PM
I have recently ordered my custom board from JLCPCB with STM32F070F6P6. When the board arrived to me, I tried to connect the CPU to ST-LINK V2, but it would not connect. I have checked all the connections on the board and everything seems to be good. I have also checked the voltage with an oscilloscope, and again it seems to be good - the voltage is stable 3.3V. I have completely no idea why it can not connect to ST-LINK. I am attaching below the picture of the schematic of my board. I am connecting SWDIO (PA13) and SWCLK (PA14) via J2 01 and 02 pins. The power comes from ST-LINK (3.3V from the voltage regulator). I tried with and without RESET and nothing changed. Am I doing something wrong?
2025-05-13 1:10 PM
Hello @KarolW and welcome to the ST Community.
Could you please give a picture of your ST-LINK V2.
Best Regards.
STTwo-32
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2025-05-13 1:46 PM
In addition to the request of @STTwo-32: the original ST-LINK/V2 do not output a voltage of 3.3V to supply a target, but only check whether the target voltage is correct.
But first of all, to assess your problem, you need the image of at least the back of the ST-LINK/V2.
Regards
/Peter
2025-05-13 1:47 PM
The 3.3V needs to go to Pin 1 or 2 (VTarget) of the ST-LINK/V2 20-pin Header
This is in addition to the SWDIO, SWCLK, and GND you have from your header
STM32 Cube Programmer should be reporting this 3.3V being present.
If you have a counterfeit ST-LINK (gum stick), then ST is unlikely to support.
The NRST pin needs to be connected for "Connect Under Reset" to be viable.
2025-05-13 2:47 PM
NRST is poorly connected. See for reference schematics:
AN4325
Application note
Getting started with STM32F030xx and STM32F070xx series hardware development
hth
KnarfB
2025-05-17 3:40 PM
Here is my ST-LINK V2 (the first picture), but I guess it is a counterfeit ST-LINK, but according to that I ordered a new ST-LINK. It is STLINK-V3MINIE (the second picture) and this is the original one. I connected that in the same way, and I am facing the same issue. The microcontroller on my board connected via STLINK-V3MINIE is not responding. It is really strange, because I have another board from my previous project, where I have a very similar circuit and there is STM32F030F4P6 and there everything is good - the microcontroller responds via these STLINKs. The only idea that I have for now is that the ICs were somehow damaged during an assembly in JLCPCB, but I am not sure about that.
2025-05-17 5:32 PM
>> The only idea that I have for now is that the ICs were somehow damaged during an assembly in JLCPCB, but I am not sure about that.
That's probably harder than you'd imagine. More likely a board or electrical issue. Double check orientation and wiring
Perhaps a high resolution, large, in-focus, picture of the board. Show connectivity with ST-LINK