This project is a test of interfacing an Arduino to an 82C55A parallel I/O chip. I used an Arduino Nano clone.
There's not really any practical reason to do this: I just wanted to make sure how to use the 82C55A before using it in a different project.
Picture of the test circuit:
The connections between the Arduino pins and the 82C55A pins are described in code comments. The demo code puts all ports in mode 0 (basic I/O), configures ports A and C for output, and port B for input. My test circuit has LEDs connected to port A and DIP switches as inputs to port B.