I spent many hours designing a motherboard in KiCad. It looks like it would work! No, this isn't retro anymore, but I think what I really liked about the Z80 was that it is simple, unlike modern processors, and powerful, unlike most arduinos. It has a DIP pinout, and it is simply the perfect combination of features for me to make a computer with. Since more powerful things are more complicated, and complicated projects can be fun, I realized what I was really aiming for was the most powerful Z80 computer I could build from scratch, then the best OS I could make for it. So it's new features are SUPER COOL (in my opinion).

New Design Features

• 2 Clocks for CPU, one for accessing slow devices and one for faster devices
• RTC with interrupts to allow better multitasking and device polling, and of course timekeeping
• Compatible with ATX power supply
• Standard front panel connector
• UART
• built-in USB to PS2 keyboard converter
• 32KB EEPROM
• 32KB RAM
• IDE connector

I understand that many people who build computers with the Z80 are looking for a retro computer experience, to run old programs OSes or games they remember from the 80's. I didn't ever have that, so I don't really resonate with it. I found out about the Z80 by looking for something more powerful than an Atmel chip, because the computers I was trying to make were too big for it. That was 4 years ago, before I knew what an address bus was. So that is why I think in terms of motherboards, and video cards, and that every computer must have keyboard input and video output.

I also may add more things, like a floppy disk controller. Or any other ideas anyone else has.

Also, its about 335$ for 3 boards from OSH park, so I am going to see if I can do it a bit cheaper: decrease board size - or make a 2-layer PCB with vias underneath chips at home (Yieks!)

Here are some pics of the new board to add to my file uploads: