Arduino is a trademark that manufactures microcontroller development board. Arduino UNO is one type of development board produced by Arduino, and the new series is arduino uno R3.
Arduino UNO R3 is a computing platform that is very easy to use. Arduino UNO R3 is ATmega328P microcontroller based. According datasheet from ATmega328P, Arduino UNO R3 has a 14 pin digital input / output, and 6 of them can be used as PWM output pin. Arduino UNO R3 also has 6 analog inputs, has a 16MHz crystal, a USB port which can be used to download the program, a power jack, a reset button, and ICSP header.
Arduino features shown in the diagram above. Arduino UNO R3 provide + 5V, 3.3V and GND pin as a power source if needed by sensors or other devices. Users can also use the SDA and SCL pins on the pin number 27 and 28. Features ADC (Analog to Digital Converter) can be used on 23-28 pins. While the interrupt feature can be used on pin number 4 and 5 (pin number 4 is int0 and pin number 5 is int1). Serial communication (RX and TX) is provided on pin numbers 2 and 3.
Arduino Uno R3 design is very simple to facilitate the user in using it. On the left we will see an electric jack socket. Power jack is compatible to the power supply voltage 9-12V. In addition, we will see the USB port to communicate with a computer, either in downloading a program or data transfer via USB. As an indicator, arduino provides 4 LEDs. 1 for the power indicator, two LED indicators for serial communication (RX and TX), and 1 other LED connected at pin 13.
The ATmega328 microcontroller datasheet shows the various features that can be used on the Arduino UNO R3.