Data Sheet

The maximum length and width of the Mega2560 PCB are 4 and 2.1 inches respectively,
with the USB connector and power jack extending beyond the former dimension. Three
screw holes allow the board to be attached to a surface or case. Note that the distance
between digital pins 7 and 8 is 160 mil (0.16"), not an even multiple of the 100 mil spacing
of the other pins.
The Mega2560 is designed to be compatible with most shields designed for the Uno,
Diecimila or Duemilanove. Digital pins 0 to 13 (and the adjacent AREF and GND pins),
analog inputs 0 to 5, the power header, and ICSP header are all in equivalent locations.
Further the main UART (serial port) is located on the same pins (0 and 1), as are external
interrupts 0 and 1 (pins 2 and 3 respectively). SPI is available through the ICSP header on
both the Mega2560 and Duemilanove / Diecimila. Please note that I2C is not located on the
same pins on the Mega (20 and 21) as the Duemilanove / Diecimila (analog inputs 4 and 5).