The Arduino Leonardo is a microcontroller board based on the ATmega32u4. 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.
Specifications
Microcontroller
ATmega32u4
Operating Voltage
5V
Input Voltage (recommended)
7-12V
Input Voltage (limit)
6-20V
Digital I/O Pins
20 (of which 7 provide PWM output)
PWM Digital I/O Pins
7
Analog Input Pins
12
DC Current per I/O Pin
40 mA
Flash Memory
32 KB (ATmega32u4) of which 4 KB used by bootloader
SRAM
2.5 KB (ATmega32u4)
EEPROM
1 KB (ATmega32u4)
Clock Speed
16 MHz
Note
The Arduino Leonardo can be powered via the micro USB connection or with an external power supply. The power source is selected automatically.
The Leonardo has a resettable polyfuse, If more than 500 mA is applied to the USB port, the fuse will automatically break.
Download the latest Arduino IDE
The open-source Arduino Software (IDE) makes it easy to write code and upload it to the board. This software can be used with any Arduino board.
The Arduino Nano is a small, complete, and breadboard-friendly board based on the ATmega328. It has more or less the same functionality of the Arduino Duemilanove, but in a different package. It lacks only a DC power jack, and works with a Mini-B USB cabl