An USB isolator will help eliminate ground loops and cuts down electromagnetic interference (EMI) between the computer as well as connected system. 1x GND 3V3 (P2 with two pins 2.54mm) connector can be utilized to electricity externally the WCH CH569 MCU (it is usually recommended to eliminate the P4/SHUNT in https://gwendolynm061wne7.bloguerosa.com/profile