2: Arduino Port to Matrix Row Column Mapping

For the 8 row x 16 column LED matrix, 24 control signals are needed.
While the Arduino cannot supply the power required by the matrix board,
they need to share a common ground as a signal reference.

Note that besides the standard digital pins, the Arduino's analog pins can be programmed to be used as
digital GPIO pins.

(diagrams from circuito.io)

Arduino Mega

• 54 Digital pins
• 16 Analog pins

Arduno Uno

• 14 Digital pins
• 6 Analog pins