stpm32: Is GND shared between AC and DC?

[NguyenAnhHieu_]

Hello everyone, I am learning about STPM32 design and I am wondering about the power source for the IC to operate. Mass (GND) is shared between AC and DC? This seems unreasonable. Hope everyone shares. knowledge.

[AScha.3]

Hi,

so whats the problem ?  

The STPM32 is powered with the cpu, from vcc , 3.3V .

And this GND is connected to a mains line , so all the circuit is on line voltage. Dangerous !

Nothing for beginners or if not trained for needed safety measures when working on dangerous voltage.