Arduino Uno R3 (A000066)

The Arduino Uno is a microcontroller board based on the ATmega328 (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.

Main difference from all preceding boards in that it does not use the FTDI USB-to-serial driver chip.
Some additional features coming with the R3 version are:

• ATmega16U2 instead 8U2 as USB-to-Serial converter
• 1.0 pinout: added SDA and SCL pins for TWI communication placed near to the AREF pin and two other new pins placed near to the RESET pin, the IOREF that allow the shields to adapt to the voltage provided from the board and the second one is a not connected pin, that is reserved for future purposes
• stronger RESET circuit

"Uno" means one in Italian and was chosen to mark the release of Arduino Software (IDE) 1.0. The Uno board and version 1.0 of Arduino Software (IDE) were the reference versions of Arduino, now evolved to newer releases. The Uno board is the first in a series of USB Arduino boards, and the reference model for the Arduino platform; for an extensive list of current, past or outdated boards see the Arduino index of boards. For a comparison with previous versions, see the index of Arduino boards.

Specifications

• Microcontroller: ATmega328
• Operating Voltage: 5V
• Supply Voltage: 7-12V (recommended)
• Maximum supply voltage: 20V (not recommended)
• Digital I/O Pins: 14 (6 with PWM output)
• Analog Input Pins: 6
• DC Current per I/O Pin: 40mA
• DC Current for 3.3V Pin: 50mA
• Flash Memory: 32KB (ATmega328), 0.5KB used by OPTIBOOT bootloader
• SRAM: 2KB (ATmega328)
• EEPROM: 1KB (ATmega328)
• Clock Speed: 16 MHz