The Arduino Leonardo Ethernet board is based on the ATmega32U4 microcontroller and the new Wiznet W5500 embedded Ethernet controller. The board has 20 digital I/O pins (7 can be used as PWM outputs and 12 as analog inputs). Additional features include a 16MHz xtal oscillator, RJ45 connection, micro USB connector, power jack, ICSP header, and a reset button.
The Leonardo ETH differs from the preceding Ethernet board in that the ATmega32u4 has built-in USB communication, eliminating the need for an external USB-to-serial converter. This allows the Leonardo ETH to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port.
