When I was young, I always wanted to own an ECB system. ECB was a standard microcomputer bus in Germany, comparable to S100 in the USA, but technically superiour. With time, modular, cheap and simple computer systems became rare. The eighties are now long gone, but I still want an ECB system. So I built my own - for hack value.
Thinking about ECB, the Z80 is the obvious choice. It is a great CPU, but I used it enough that it got boring to me. Back then, I had a brief contact with the MCS-48 family, and when I found out they can still be bought, the decision was made. The awful architecture will make some scream and cry, but if it was easy, everybody could do it. Hack value, remember? And that's how it all started.
Once the SBC worked, a subrack was needed, containing the power supply and the backplane. I got a cheap parallel backplane and a used subrack from Ebay, modifying both as needed.
Currently, there are: