Description Technical parameters: 1. 20 digital input/output port RX and TX, D2 ~ D13, A0 ~ A5 2. 8 analog input port A0 ~ A7 3. 1 to the TTL level a serial port to send and receive port RX/TX 4. 6 PWM port, D3, D5, D6, D9, D10, D11 5. Using Atmel Atmega168P-AU microcontroller 6. Support serial download and ISP download 7. Support external 3.3V ~ 12V dc power supply 8. Support the Li-ion polymer batteries while direct connecting Vcc Pin 9. 16 MHZ clock frequency