Reposting as it's own thread instead of discussing it in-line in the PCB thread (which didn't feel entirely right, TBH). By way of context: I'm going to be attending the Cyberpunk-themed Neotropolis ...
When we design a microcontroller (MCU) project, we normally leave a few port lines unused, so that last-minute requirements can be met. Invariably, even those lines also get utilized as the project ...