STM32F070F6P6 is not connecting to st-link

[KarolW]

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?

[STTwo-32]

Hello @KarolW and welcome to the ST Community.

Could you please give a picture of your ST-LINK V2.

Best Regards.

STTwo-32

[Peter BENSCH]

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

[Tesla DeLorean]

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.

[KnarfB]

NRST is poorly connected. See for reference schematics:

AN4325
Application note
Getting started with STM32F030xx and STM32F070xx series hardware development

hth

KnarfB