Z1a - The Keyboard
So, at this point the computer could save to and load from the CF card. But I was still controlling it via a PC keyboard, a USB-serial adapter and a serial port. It needed a keyboard of its own.
I thought about hooking up a PS/2 keyboard, but they're getting hard to find now. Some USB keyboards still have PS/2 functionality via one of those little purple adapters, but it's hard to tell which ones as it's no longer an advertised feature.
Adding a USB interface seemed far too complicated, and not at all 1980s.
So I decided I would build my own keyboard. This is pretty simple. Buy some key caps and shuffle them around until you have a layout you like. Design a PCB to accommodate them. Buy a bunch of keyboard switches (Cherry MX Red, in this case). Stick it all together. I haven't even needed to worry about debouncing, because so far the Cherry switches don't seem to bounce.
As you can see, I've gone for a slightly PC-ish but also uniquely weird layout, because if there's one thing that says 1980s home computer, it's a weird keyboard layout.
The cable connections are on the right-hand side in anticipation of a future all-in-one motherboard with I/O chips on the right and video on the left. For the time being it means that the cables snake awkwardly from right to left to reach the GPIO card.
But what good is a keyboard without some software?