The Arduino Uno is arguably the best-known and most widely used Arduino. It uses an ATmega328 microcontroller. This controller features 14 digital inputs and outputs (6 of which can be used in PWM mode), 6 analog inputs, a 16 MHz crystal oscillator, a USB Type-B port, a power supply connector, an ICSP connector, and a reset button. The board contains everything you need to program microcontrollers. In revision three, an ATmega16u2 replaces the ATmega8u2 from the previous version as the USB-to-serial converter. Simply connect your computer and the board via a USB cable, or use an external power supply or battery, and you're ready to go. This version of the Arduino Uno is the DIP (also DIL for Dual In-Line or Dual In-Line Package) version. This version differs from the SMD version by having a larger and more easily replaceable microcontroller in a DIP package. This makes it significantly easier to replace a broken controller or to use a programmed microcontroller independently of the Arduino board in a separate circuit.
