The Arduino Uno is a microcontroller board based on the ATmega328. The board contains everything necessary to develop with this microcontroller. It can easily be connected to a PC via USB cable or powered by an external power supply or battery and get started. Arduino Uno differs from all its predecessors in that it does not use a USB/serial converter chip from FTDI. Instead, it uses an ATmega16U2 programmed as a USB/serial converter. The Arduino Uno has 14 digital I/O pins (6 of which can be used as PWM output) and 6 analog inputs. It also has a 16 MHz crystal, USB connector, external power supply socket, ICSP header and a reset button.