An USB isolator aids reduce ground loops and lessens electromagnetic interference (EMI) in between the pc and the linked machine.1x GND 3V3 (P2 with two pins two.54mm) connector can be utilized to electricity externally the WCH CH569 MCU (it is recommended to get rid of the P4/SHUNT in that circumstance It isn't obligatory given that the 3V3 LDO IC