KZ80 Progress Update

As these things tend to do, work on the KZ80 has slowed. As a quick recap, the mainboards have been ordered (and should be sent to the fab on the 6th), I have switches for the keyboard enroute, and the display arrives whenever it arrives.

Much of what remains is the design of the peripheral board, which is, as it turns out, the bulk of the work. I think that it might make sense to add in the SIO/2 first to get some sort of interface built. Following onto that, I can start working on the keyboard; once the keyboard is done, the display can be worked on.

Right now, that means I'm reading up on the SIO/2. My print copy of How to Build Your Own Z80 Computer shows up soon, and I've got the Z80MC coming that I can learn how to do some programming on as well. There's a ton of work to do, and it doesn't have to be done all at once. Slow and steady wins the race, or so I'm told.

Right now, my approach is still to use ~5 MCP I2C I/O expanders. In essence, the mega1284 becomes an I2C extender for the Z80. I don't necessarily mind this, but I wonder if it isn't overkill. I've tried to sign up for the RetroBrew forums; maybe posting there will be informative.

I've also spent a fair amount of time trying to get my RC2014 working; no luck so far. I did get the emulator working, and seeing as I've ordered the Z80 membership card [1], got the Z80MC emulator working too. I've been tinkering around with CP/M, trying to decide if it's something I'll eventually want on my laptop. I do like the monitor front card. Which reminds me, I need to think about my monitor program and figure out how I want to make that work. I could adapt the Z80MC monitor program, but I think I'm going to do a survey of Z80 monitors and figure out what I want, exactly.

I did buy a Compaq SLT/286, so that will occupy some time. I figure the BIOS hardware abstraction should make some of the operating system writing easier, and it'd make a good testbed for OS development in a constrained environment. It also follows the revisiting what I need out of my computing environment. I'll write about that at some point.

[1]http://www.sunrise-ev.com/z80.htm

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