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. Note: This Arduino
Leonardo comes with pre-soldered headers and 2.1mm power
connector. |Input Voltage (recommended)||7-12V| |Input Voltage
(limits)||6-20V| |Digital I/