How should I do a power cycle?

[Vmere.1]

Which Pin should I set and reset to make a power cycle happen in STM3G4 or any popular STM32F3xxx.. ??

I have 2 mcu's and with one of it I want to do a power cycle..

I mean to remove the power and connect it again. What should I do here?

[LCE]

Then you need some more hardware, most importantly a P-channel MOSFET.

Something like this, although when switching 3V with 3V IOs you can leave the npn.