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 microcontroller; simply connect it to a computer with a USB cable or power it with an 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 Microcontroller: ATmega32u4 Operating voltage: 5 V Supply voltage (recommended): 7-12 V Supply voltage (limits): 6-20 V Number of digital I/O pins: 20 Number of PWM pins: 7 Number of analog input pins: 12 Max DC current for each I/O pins: 40 mA DC current for 3.3 V out: 50 mA Max DC current for 3.3 V pin: 1 A (if supplied with an external adapter) Flash memory: 32 kB (ATmega32u4, 4 kB is used by bootloader) SRAM: 2.5 kB (ATmega32u4) EEPROM: 1kB (ATmega32u4) Clock speed: 16 MHz Length: 68.6 mm Width: 53.4 mm
