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 theGetting started with the Arduino Leonardo.

Features:

1. Microcontroller: ATmega32u4 with built-in USB communication.
2. Digital I/O Pins: 20 pins for versatile input/output operations.
3. PWM Channels: 7 pins capable of Pulse Width Modulation for motor and LED control.
4. Analog Input Channels: 12 channels for reading analog sensors.
5. ICSP Header: For direct programming of the microcontroller.

Specifications:

1. Operating Voltage: 5V for standard Arduino compatibility.
2. Input Voltage (Recommended): 7-12V, with limits of 6-20V.
3. Flash Memory: 32 KB total, 4 KB reserved for bootloader.
4. SRAM: 2.5 KB for variable storage.
5. EEPROM: 1 KB for persistent data storage.
6. Clock Speed: 16 MHz for efficient processing.

Package includes:

1 x Arduino Leonardo with Headers