The
Arduino Mega is a micro-controller board based on the ATmega2560. It
has 54 digital input/output pins (of which 14 can be used as PWM
outputs), 16 analog inputs, 4 UARTs (hardware serial ports), 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 Mega is
compatible with most shields designed for the Arduino Duemilanove or
Diecimila.
The Mega 2560 R3 also adds SDA and SCL pins next to the
AREF. In addition, there are two new pins placed near the RESET pin. One
is the IOREF that allow the shields to adapt to the voltage provided
from the board. The other is a not connected and is reserved for future
purposes. The Mega 2560 R3 works with all existing shields but can adapt
to new shields which use these additional pins.
