Hi Steve,

The 8255 may well be dead (although the abundance of hits a search would turn up on this site might contest that point), but what it does is not. Thus, to learn what it does, and how it does it, indeed is foundational. It is not foundational to the µ-controller but to the subject.

That being said, maybe there are better ways to teach the same thing. But cliches don't become cliches by being wrong. The fact that the 8255 has so adamantly taken Dillon Thomas' advice* (as witnessed by the aforementioned search hits on this very sight) suggests that there is some value of which industry professionals have lost sight.

Joe

* Do not go quietly into that good night. Rage, rage against the dying of the light.