Arduino: Arduino Uno based on  Atmel AVR ATmega328 MCU

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arduino unor3.PNG

Kit Overview


The Arduino Uno is a microcontroller board based on the ATmega328ATmega328. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz 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.


The Uno differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip. Instead, it features the Atmega16U2 (Atmega8U2 up to version R2) programmed as a USB-to-serial converter.


Revision 2 of the Uno board (A000046A000046) has a resistor pulling the 8U2 HWB line to ground, making it easier to put into DFU mode.


Revision 3 of the board (A000066A000066) has the following new features:

  • 1.0 pinout: added SDA and SCL pins that are 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. In future, shields will be compatible both with the board that use the AVR, which operate with 5V and with the Arduino Due that operate with 3.3V. The second one is a not connected pin, that is reserved for future purposes.
  • Stronger RESET circuit.
  • Atmega16U2 replace the 8U2


Ordering option:

Part NumberDescription
A000046A000046Revision 2 of the Arduino Uno board
A000066A000066Revision 3 of the Arduino Uno board


Key Applications: Building Automation, Industrial Automation.

More Development Kits and Tools
More Atmel Development KitsAtmel Overview
Development Platforms & Kitselement14 Knode


Development Tools


Software Development Tools:


Tool TypeSupplierMPNSupported FamilyDescription

Atmel Studio 6



Atmel Studio 6 Integrated Development Environment (IDE) is the integrated development environment (IDE) for developing and debugging Atmel ARM® Cortex™-M and Atmel AVR® microcontroller (MCU) based applications. The Atmel Studio 6 IDE gives you a seamless and easy-to-use environment to write, build and debug your applications written in C/C++ or assembly code. Learn More


Micrium uc/OSIII


μC/OS-III is Micrium’s newest RTOS, designed for developers who need to save time on their current and next embedded sytem projects. Learn More




SEGGER embOS (Real Time Operating System) follows strict, yet efficient coding and documentation standards. embOS is a priority-controlled real time operating system, designed to be used as foundation for the development of embedded real-time applications. Learn More


Hardware Development Tools:


Tool TypeSupplierMPNSupported FamilyDescription
Debuggers, Emulators & JTAG ToolsAtmel


AVR UC3 / AVR XMEGA / megaAVR / tinyAVRAVR Dragon JTAG Debugger Starter Kit for for 8-bit and 32-bit AVR devices
Debuggers, Emulators & JTAG ToolsAtmel


AVR UC3 / AVR XMEGA / megaAVR / tinyAVRAVR ONE! professional development tool for all Atmel 8-bit and 32-bit AVR devices
Debuggers, Emulators & JTAG ToolsAtmel


AVR UC3 / AVR XMEGA / megaAVR / tinyAVRAVR JTAGICE mkII mid-range development tool for Atmel 8-bit and 32-bit AVR devices
Debuggers, Emulators & JTAG ToolsAtmel


AVR XMEGA / megaAVR / tinyAVRAVRISP mkII Programmer for field upgrades of Atmel 8-bit AVR microcontrollers with ISP or PDI interfaces




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Technical Documents

Learning Center
Application NoteAtmel: TV Control Touch Keyboard
Application NoteAtmel: Digital Filters with AVR
Application NoteAtmel: Understanding ADC parameters
Application NoteAtmel: LED Driver Library for 8-bit AVR


Design Elements
SchematicsArduino: Uno schematic_Rev3
Reference DesignArduino: Uno Reference Design_Rev3
Code SnippetArduino: SCP1000 Barometric Pressure Sensor Display
Code SnippetArduino: Sample Code for Digital Pot Control
Code SnippetArduino: Sample Code for Servo Library


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Kit Features

arduino unor3.PNG

  • Operating Voltage: 5V
  • Microcontroller: ATmega328ATmega328
  • Input Voltage (recommended): 7-12V
  • Input Voltage (limits): 6-20V
  • Digital I/O Pins:14(of which 6 provide PWM output)
  • Analog Input Pins: 6
  • DC Current per I/O Pin: 40mA
  • DC Current for 3.3V Pin: 50mA
  • Flash Memory: 32KB (ATmega328ATmega328) of which 0.5 KB used by bootloader
  • SRAM: 2KB(ATmega328ATmega328)
  • EEPROM: 1KB(ATmega328ATmega328)
  • Clock Speed: 16MHz





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Kit Contents


  • Arduino Uno board
  • The ATmega328 on the Arduino Uno comes preburned with a bootloader



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