Original Circuit Diagram: Arduino UNO R3 Now, have a look at our favorite Arduino UNO to find out the AVR chip inside. It is ATMega328P-PU, a low-power version of the traditional ATMega328-PU. The P ...

[jelengar] liked the ease of use of the Arduino, but wanted a much higher pin count. He set about converting the ATmega Controller for use with Wiring, the code that the Arduino IDE is based on.