First off, he’s included level converter chips to managed the 3.3V/5V issues. Second, he uses latch chips to translate eight pins on the Arduino Mega to sixteen pins on the display.

The Arduino Mega 2560 R3 is positioned on a suspended platform, with the anodes controlled on the Digital Pins as opposed to the cathodes on remapped AnalogInputs.

Developers, electronics engineers, makers and hobbyists looking for an affordable integrated circuit tester may be interested in this automated Arduino IC tester, created using an Arduino Mega ...