At the heart of Arduino UNO R3 is a microcontroller ATmega328 processor with a clock frequency of 16 MHz. The board has 14 digital inputs / outputs, 6 analog inputs and has a memory in a volume of 32 KB. For programming and communication with the computer, you will need USB cable AB.
Version R3 is the latest model in the line of UNO and different from previous versions of USB-UART converter based ATmega16U2 instead of the previously used chips 8U2 and FTDI.
Arduino UNO R3 can be powered from the USB port of the computer and from the external power source voltage 6.6-12V.
Each of the 14 digital pins on the board Arduino UNO R3 can be used as input or output. They work with a voltage of 5V. Each pin can give or take makimum 40mA. The conclusions have built pull-up resistor (disconnected by default) of 20-50 ohms resistance.
The analog pins:
Arduino UNO R3 to have 6 analog inputs are numbered A0 to A5, each of them has a 10 bit resolution (ie 1024 different values).
Arduino UNO R3 can be programmed with the aid of software Arduino.
ATmega328 board installed in the Arduino Uno comes with wired bootloader that allows you to upload code to the Arduino without the use of an external hardware programmer. Sometimes is used to link the original STK500 protocol