Arduino Uno R3 Compatible ATMega328P+ATMega16U2

This is the new R3 version of the Arduino Uno R3 compatible board, with a replaceable ATmega328P chip. 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 16 MHz ceramic resonator, 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 3 of the board 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 with both the board that uses the AVR, which operates with 5V and with the Arduino Due that operates with 3.3V. The second one is a not connected pin, that is reserved for future purposes.
• Stronger RESET circuit.
• Atmega 16U2 replace the 8U2.

Power
There Arduino Uno can be powered using these 4 methods:

• USB (5V) - The Uno will use any 5V power supply with a USB Type B connector. Total current drawn will be limited by the supply, most PCs only provide 250-500mA so bear that in mind if you are looking to power your project directly from a PC.
• 2.1mm Centre-Positive Barrel Jack (Regulates Voltage from 7-12V DC) - The Uno will use any 7-12V source here, as long as it is connected center positive and is 7-12V DC. 
• V_in Pin/GND Pin on Power Header on board - This pin can either be a power input (7-12V DC) or to drawn power directly from the barrel jack supply.
• 5V Power Pin on Power Header on Board - This pin can either be used as a 5V output pin or to supply 5V. 

When powering the circuit via multiple methods, the 7-12V supply options will take preference over the 5V, and the 5V will be used for data transfer.

Memory
The ATmega328 controller chip contains 32 KB of memory (0.5 KB of this is reserved for the bootloader). It also has 2 KB of Static RAM and 1 KB of EEPROM.

Programming
The Arduino Uno can be programmed with the Arduino software. Select "Arduino Uno from the Tools > Board menu (according to the microcontroller on your board

The ATmega328 on the Arduino Uno comes burned with a bootloader that allows you to upload new code to it without the use of an external hardware programmer. 

You can also bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial Programming) header using Arduino ISP or similar.

Please note these are VERY LOW cost boards from China. If you expect a premium product, this is NOT for you. These boards might have scratches on them, might not be the cleanest, and the packaging might have scratches or small tears. For example, if the board has pin headers, they are often ship to us from China all together in a bag, and the pins might be slightly bent or protrude through the bag. If this is not acceptable, please look for a more premium product. After all our costs (10% GST, over 10% eBay/PayPal fee and "Free" shipping we have to pay for), you can appreciate that there is very, very little profit margin left for us. We bring you these products at a very good price, but keep in mind it is a very low cost, cheap and nasty cheap product - exactly the same as similar price products sold by other sellers.

Specifications

• Microcontroller: ATmega328P
• Digital I/O Pins: 20, or which 6 have PWM funtions
• Analog Input Pins: 6
• Flash Memory: 32 KB (0.5 used by bootloader)
• SRAM: 2 K
• EEPROM: 1 K
• Clock Speed: 16 MHz
• Weight(board only): 25 g
• Dimensions: 68.6mm * 53.4mm
• Operating Voltage: 5V DC
• Input Supply Voltage: 7 to 12V DC
• Operating Temperature: -30°C to + 80°C

Package Includes

1 x Arduino UNO board