The processor core of Nano CH340 is atmega328p-au. It is as same as the official Arduino Nano in addition to driver file and USB to serial chip (CH340G). It also has a 14 digital input / output interfaces (6 of which can be used as PWM output), 8 analog input interfaces, 1 16MHz crystal oscillator, 1 mini USB port, 1 ICSP interface, and a reset button. The ICSP interface is used to burn firmware to Atmega328P-Au. Since this chip we burn firmly in front of the factory, it is generally not available. When using the Mini USB cable, we can use the VIN GND (DC 7-12V) to power.