Cannot connect to STM32L05x MCU with CubeProgrammer and ST-Link V3

[JFOLE.1]

Cannot connect to STM32L05x MCU with CubeProgrammer and ST-Link V3 using the CLI with both "connect under reset" and "Normal" modes. However using the same setup I can connect with ST-Link V2.

Is there any reasoning for this?

[Tesla DeLorean]

Select a slower SWD clock rate, try 1 or 4 MHz rather than 24 MHz

Does your interface connect the NRST pin?

[JFOLE.1]

Yes interface connects to NRST. Clock speed selection doesn't affect it, it will connect in Normal mode but never under reset.

[JFOLE.1]

I have two IC's that I am working with in this project. STM32L07x and STM32L05x.

With STM32L07x I can connect consistently with ST-LINK V2/V3.

However with STM32L05x it is very inconsistent.

I have tried this with numerous samples of each MCU and have concluded that it must be the MCU compatibility.

Another point to note, I can run STM32L07x in both Normal and under reset mode. With STM32L05x I can only use Normal mode, and even with this it can be very inconsistent.

Any ideas?

[S.Ma]

what voltage the stm32 runs with?

[JFOLE.1]

3.7V at DCDC which then outputs 1.8V to MCU