Arduino Main Board

This is the new Arduino Uno R3. A few changes have been made including the addition of SDA and SCL pins that are near to the AREF pin and two other new pins placed near to the RESET pin, the IOREF that allow the shields to adapt to the voltage provided from the board. In the future, shields will be compatible both with the board that use the AVR, which operate with 5V and with the Arduino Due that operate with 3.3V. This version also includes a stronger reset circuit and an ATmega16U2 in place of the 8U2. Please see the Arduino support forum for more information about this new board revision and bootloader.