Since the next step is to test the MCU, I spent part of the morning wire wrapping the input side of the MCU CPLD. Here it is:
The blue wires are address and data and the yellow are the bus control. I also connected the 6 new Arduino lines to the chip. I confirmed continuity. I have just started the process of testing. I’m starting out making sure the new lines are asserted properly. Once I know they are, I’ll start actually trying to use the MCU and ensuring it works as expected.