ARDUINO COMPATIBLE LEONARDO R3

The Arduino Leonardo is a micro-controller board base on the ATmega32u4 (datasheet). It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs);  a 16 MHz crystal oscillator, a micro USB connection, a power jack, an ICSP header, and a reset button. It contains everything need to support the micro-controller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get start.

The Leonardo differs from all preceding boards in that the ATmega32u4 has built-in USB communication; eliminating the need for a secondary processor. This allows the Leonardo to appear to a connected computer as a mouse and keyboard; in addition to a virtual (CDC) serial / COM port. It also has other implications for the behavior of the board