rduino Mega board from Arduino Officials based on ATmega16U2. The Official Arduino Mega 2560 is Rev3 development board based on ATmega2560 microcontroller. The board has 54 digital input/output pins (of which 14 can be used as PWM outputs), 16 analogue inputs, 4 UARTs (hardware serial ports), 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 an AC to DC adaptor or battery to get started.
The Mega is compatible with most shields designed for the Arduino Uno, Duemilanove or Diecimila. The Arduino Mega can be powered via the USB connection or with an external power supply. The power source is selected automatically. The Arduino Mega2560 has a number of facilities for communicating with a computer, another Arduino or other microcontrollers.
Revision 2 of the Original Arduino Mega 2560 board has a resistor pulling the 8U2 HWB line to ground, making it easier to put into DFU mode.
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 both with the board that use the AVR, which operate 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
Model Mega 2560 Processor IC ATmega16U2 Operating Voltage 5VDC Current per I/O pin 40mA DC Memory 256KB flash memory of which 8KB used by bootloader
Input voltage (recommended) range from 7V to 12V Input voltage (limit) Range from 6V to 20V Length (mm) 102 Width (mm) 51 Height (mm) 30 Weight (gm) 40 Shipment Weight 0.1 kg Shipment Dimensions 12 × 4 × 3 cm