The Arduino Leonardo is a microcontroller board based 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 needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.
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; these are detailed on the getting started page.
Technical Specifications
Model
Leonardo
Microcontroller
ATmega32u4
Operating Voltage
5V
Input Voltage (Recommended)
7-12V
Input Voltage (limits)
6-20V
Digital I/O Pins
20
PWM Channels
7
Analog Input Channels
12
DC Current per I/O Pin
40 mA
DC Current for 3.3V Pin
50 mA
Flash Memory
32 KB (ATmega32u4) of which 4 KB used by bootloader
