Arduino Board is for robotics engineering,robotics competition,science experiments on high school,primary school,secondary school,smart home.
1. Output: Add SDA and SCL pins near the AREF pin, and two new pins placed near the RESET pin. IOREF allows the voltage supplied on the adaptive board to be shielded. In the future, the shield will be compatible with the use of AVR board, AVR with 5V work, using 3.3V work. The second is the unconnected pin for future purposes.
2. Stronger RESET circuit.
3.ATmega 16U2 replace 8U2.