That refers to an aggregation of what I've seen over the last half-year or so, rather than this specific case.

Time and again, I see questions posed by obviously inexperienced, and, in some cases, obviously student-level beginners. They ask things like, "How can I make this work?" but get answers such as, "You shouldn't want to make this work."

You've done it. I've done it. It's an easy reaction, but not a helpful one. As I've mentioned before, telling me how to build a clock doesn't tell me what time of day it is, no matter how well you describe the business of clock building.

I've pointed out a few times with respect to keypad and LCD queries, that the NMIY-0031 board, from New Micros, or whatever they're called (just google NMIY-0031) has an LCD interface along with code that handles it as a memory-mapped peripheral. Further, it also has a 4x5 keypad scanner that it supports. It's firmware, of course, but it is all you need.

That's ONE way of handling this problem, WITH THE EXCEPTION that it doesn't address the O/P's question. He wants to make it work with the 74C922, which we all agree is a probably too-costly alternative, but it is what he wants. Since he didn't say, and we didn't ask, WHY he wants to do that, I think we should leave him alone in that respect.

All he's saying is, "What if I did it THIS way?" That's a question that deserves an answer, even if the approach is flawed in your view or mine.

RE