After my last failed attempt to retrofit my first Z80 build to run CPM I decided to work on a new board with the design from Grant Searle’s CPM 2.2 .

I wanted to have a prototype working on breadboard before moving to a protoboard, after a few days I was able to complete the breadboard prototype.

 

The only issue is that I was NEVER able to make it work, not even something on the terminal. After a week of debugging and double checking the connections it was still not working..