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.
• 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
• SRAM 2.5 KB (ATmega32u4)
• EEPROM 1 KB (ATmega32u4)
• Clock Speed 16 MHz