Problem with connecting STlink v2 and STM32L451CCU6

[RMilo.1]

We buy original STlink v2 and we hawe problem with connect to STM32L451CCU6. On china programator MCU connect all time. On STlink connect time to time and if we are connented we can't program MCU. Bellow screen, first china programator, second STlink.

Imgur: The magic of the Internet

Imgur: The magic of the Internet

[TDK]

> Target Voltage: 1.48V

In the second picture, the voltage on the target is not sufficient. Recheck your power scheme. Note that the debugger does not supply power in general.

Providing a link to your exact "STLink v2" device would be helpful.

[Tesla DeLorean]

For the ST-LINK/V2 expect to need to connect pin 1 or 2 to the VTarget from YOUR board. The boot-leg pods tend to dispense with the drivers, and so don't need to power them.

Insure common ground connection.

Show what your actually connecting, these type of "Not Working" reports with secondary symptoms are hard to diagnose/debug, start with the primary connectivity and circuit issues. Scope the SWDIO and SWCLK signals in the two cases, observe voltages.

[RMilo.1]

Ok I found problem. On chinese programator it was enough plug 3.3v from programator and MCU works, on STlink i must powered board outside. Now I have question ... Can I powered mcu from STlink like chinese programator or that didn't work

[Tesla DeLorean]

Pin 19 should provide 3.3V that might suffice

https://www.st.com/resource/en/user_manual/um1075-stlinkv2-incircuit-debuggerprogrammer-for-stm8-and-stm32-stmicroelectronics.pdf

[RMilo.1]

Yes i know that, but if I connect 3.3v (19 pin) instead Target VCC (1 or 2 pin) MCU work but i have problem with connect like first post. Can I connect 19 pin (3.3v) and pin 1 or 2, won't it damage STlink? Maybe i must connect 3.3v in other place on board?