1.on-board Atmega328P-AU microcontroller chip.
2.on-board 16 MHZ high-precision crystals.
3.on-board UART interface,convenient and serial port communication,can also use it to download the program.
4.on-board 5 V to 3.3 V power supply chip.
5.on-board 14 digital input/output pins (including 6 can be used as a PWM output),8 analog input.
6.PCB Size: (33 mm) x17.8 (mm).