I'l finding new nicknames for my DIP/DIL-based prototype :-D

DIPlodocus ? DIPlosaurus ? Anyway you get the idea.

I think that I have covered most of my needs in DIP circuits, except probably with programmable devices, such as 28/29F010, but I have enough chips to start. I can implement 11 registers as presetable up/down counters (that makes 44 chips just for counting, and as many '245 for reading them on the 2 read buses). I also have a choice of parts for the ALU, including LS parts that are almost as old as me...

I am refining the design strategy. First, create a working prototype of a given subcircuit with DIP then input the corresponding schematics in Eagle. This way, it will be easier to keep track of all the changes, because HaD can't keep the pace when a project grows beyond 10 log entries...

The major concern for the design of such a system is controllability and observability. Each new circuit will be added one after the other, to make sure that the new whole works as well as the precedent. This is why the P1 board is so important: it allows me to probe the system in detail, send signals and read the results.

The first cornerstone is the keyboard. The mouse hack is a nice idea but it is not essential for the next weeks at least, so I found a rather nice button (with integrated lever) and added it to the switchboard.

For the keyboard to work, there must be a binary counter. And for this counter to work, there must be a clock. So I think I got a working plan. Let's input the clock's schematics in Eagle...

done