54 digital input/output pins (of which 14 can be used as PWM outputs)
16 analog inputs
4 UARTs (hardware serial ports)
16 MHz crystal oscillator
Stronger reset button
Can be powered with an AC-to-DC adapter or battery to get started
Compatible with most shields designed for the Arduino Duemilanove or Diecimila
Doesn't use the FTDI USB-to-serial driver chip.
Features the ATmega16U2 (ATmega8U2 in the revision 1 and revision 2 boards) programmed as a
New 1.0 pinout: added SDA and SCL pins that are near the AREF pin
Two other new pins placed near the RESET pin
IOREF allows the shields to adapt to the voltage provided from the board
Stronger RESET circuit
Atmega 16U2 replace the 8U2
Arduino Mega 2560 Revision 3 is a microcontroller board that allows for designing electronics projects that require more I/O lines, more RAM, and more sketch memory. It comes with 54 digital I/O pins, 16 analog inputs, 4 UARTs, a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. It's also compatible with all Arduino shields that work with the Arduino Uno and Duemilanove. This board can be powered via a USB connection or an external power supply, either from an AC-to-DC adapter or battery. If you're looking for a microcontroller board designed to help develop electronics projects that can interact with the real world, the Mega 2560 project board is the perfect solution.
The Mega 2560 Revision 3 also features an onboard USB port for easy programming and debugging, making it the perfect choice for your next project. Working on Arduino Mega 2560 projects is made easier with the Mega 2560 core, an Arduino-compatible platform that makes it easy to write code and upload it to the board. When you're ready to start working on your next electronics project, consider using the Arduino Mega 2560 Revision microcontroller board.