The Arduino Mega 2560 is a microcontroller board based on the ATmega2560 (datasheet). It has 54 digital input/output pins (of which 15 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 Arduino Mega can be powered via the USB connection or with an external power supply. The power source is selected automatically. External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector. The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts. Microcontroller: ATmega2560, *Operating Voltage: 5V, *Input Voltage (recommended):7-12V, *Input Voltage (limits):6-20V, *Digital I/O Pins: 54 (of which 15 provide PWM output), *Analog Input Pins:16, *DC Current per I/O Pin:40 mA, *DC Current for 3.3V Pin:50 mA, *Flash Memory:256 KB of which 8 KB used by bootloader, SRAM: 8 KB, EEPROM: 4 KB. *Clock Speed: 16 MHz