Young ‘uns today might not remember it, but there was a time before touchscreen phones and internet-connected devices. Screens were curved, games came on cassettes, and two processors fought for dominance: the Z80 and the 6502.
Which one was best? Well, the answer depends on who you ask, but here at HackSpace magazine, we’re big fans of the Z80. We caught up with Spencer Owen, whose RC2014 Z80 computer kits are bringing people back to this processor. Take it away, Spencer…
DAYS OF EARLY SPENCER
Originally, it was my own personal project to see if I was able to design a computer, the sort of thing they had back in the 1980s. It turns out that, yeah, it was possible. I made up a machine on a breadboard – Z80-based because that was the chip I had lying about, a donation to Nottingham Hackspace. I wondered if I could put these together, and get something that worked. Yeah, I can run BASIC! I wondered, can I make a PCB out of this? I designed some PCBs and they worked! Great! I was happy.
A couple of people said, “I like your computer, have you got any spare boards?” I had a spare set, so I gave them to them free of charge. Someone else wanted a set, so there you go. I’d run out, but more people wanted them.
I thought I’d get some more printed and list them on Tindie to see if anyone wanted to buy them. As long as I made my money back, I’d be happy – and I sold out those ten in no time at all. I had to get some more, and people wanted the components to go with it, they wanted some other options – better versions of various modules. Before I knew it, I was working almost full-time on that, even though I had a full-time job, so I got to the stage where I quit the day job. I was a network engineer and server engineer for 16 years. I quit the day job and the RC2014 has been paying the mortgage for the last couple of years now.
Because I started selling through Tindie, I [initially] thought that this would be great for a bit of beer money for something on the side to help cover my own costs, but the Tindie sales were going up and up and up, and in the job I was in at the time, my enjoyment was going down and down and down. After working a full eight-hour day at work, and driving, then working for another six to eight hours, something had got to give. There were one or two things that happened at work that made things a bit easier, so I thought, ‘I’m out of here’. My honest expectation was that if I sold RC2014s full-time, I’d still need some sort of back-up job – [e.g.] work in Sainsbury’s stocking shelves – just so I’ve got some regular income. If I made enough money just selling RC2014s, then great. As it happens, I’ve not yet taken up a job in Sainsbury’s, and I’m still selling more RC2014s week-by-week.
Every couple of months or so, there’s a new module coming out to either enhance what’s already there, or add to the range. There’s a nice little traffic-light board coming out soon, so you can test your programming skills by controlling some traffic lights. It was a classic type of a test project when I first learned computing, back in the 1980s.
The virtues of the Z80
It’s a really good, solid chip. Until recently, NASA still used them in their satellites, because it was the most advanced chip that they could analyse down to the transistor level. Everything is tried and tested with the Z80. There are a lot of people who grew up with it, their first programming experience was with it – there’s a lot of knowledge out there which helps too, as well as the fact that, for a lot of people, their first computer was their first love, and if you had a BBC as your first computer, you’re probably not going to be a Z80 fan and vice versa. I’m not a 6502 fan because I set out with a Sinclair Spectrum – which has actually been proven to be the best computer in the world ever, by the way, just to slip that in.
Raw Z80 code will run on the RC2014. If you’ve got some code for, say, the Spectrum that relies on the Spectrum hardware, then that won’t work – it just won’t have the hardware to talk to. Although conversely, things that were written in BASIC back in the day almost certainly will run, because the RC2014 runs BASIC. The RC2014 Pro runs CP/M, and almost all of the CP/M software runs on it. If there’s a hardware-dependent graphics card or something, that won’t work, but as long as it can talk through the serial port, almost anything that’s CP/M will run on the RC2014.
There’s a software project for the Z88, which was Sir Clive Sinclair’s portable computer after he left Sinclair. The Z88 is still thriving, and there’s a software group that’s sprung up around that. That can now export C code directly onto the RC2014, so there is quite an ecosystem there, and people writing their own software to do that.
I don’t describe it as open-source, because I don’t share everything. I don’t share the Gerber files, so only I can make the PCBs; however, all of the schematics are open. I do encourage other people to make their own modules. All of the source code is as open as possible, so technically it’s not completely open-source, but it’s as open as it can be.
The community that has sprung up around the RC2014 has probably got about a dozen people making boards for the RC2014, so I’m now not the only person making RC2014 boards. There are now other people making boards designed for the RC2014 with either expansion boards or a different shape and size backplane, because not everyone wants that form factor. I’m more than happy for anyone to make their own board designed for the RC2014!