Ah, the Sinclair ZX Spectrum. A popular computer in Britain and beyond, but now rather thin on the ground. If you can’t find one, fear not, for now—you can apparently build a new one with new parts! [TME Retro] is here to demonstrate how.
Before you get excited, no—Sinclair has not risen from the dead. Instead, it’s simply down to the state of the retrocomputing community. There are enough reproduction parts and components out there for the ZX Spectrum that it’s now possible to assemble the whole computer from new bits. You can get new cases and new mechanical keyboards, and a 100% compatible motherboard in the form of the Harlequin board. The latter even reproduces the unobtainable Spectrum ULA glue logic chip in raw logic!
It’s neat to see the ZX Spectrum live on decades after the production lines ground to a halt. We’ve seen similar feats achieved with the legendary Commodore 64; you’d think we had enough of them given they were the best-selling computer of all time. Video after the break.
Heh, well, won’t be “all new” for much longer considering the Z80 is unfortunately finally out of production.
Soon you’ll need an adapter for an eZ80 (maybe, timing may not allow the substitution) or a microcontroller pretending to be a Z80.
But none of that distracts from this being a cool project!
I’m pretty sure that in a couple of decades ordering chips made using an outdated process will be as easy as ordering PCBs nowadays. Just send a .zip file with all the masks, wait 1-2 weeks and you get your freshly baked Z80s or ULA or 6502 or SID or Amiga OCS or…
With the number of Youtube makers trying their hands at lithography, I am hoping we’ll see a similar pattern as with 3D printing.
It would be amazing to just go on a service and within a few weeks receive shockingly cheap custom chips.
I’m hoping that it leads to a bit of a minor maker revolution for various types of things. Retro rebuilds being one.
Take a look at
https://developers.google.com/silicon
That was a good link, cheers.
There’s this. There’s Tiny Tapeout. Both are awesome, but are also sponsored by someone. I’m hoping for a future where hardware hackers don’t need to rely on charity. Just like with PCBs, 3D printing, laser cutting etc.
” no—Sinclair has not risen from the dead.”
I’m sure that I’m not the only one grateful for that! (If you’re referring to Sir Clive!)
My previous comment was not intended to be chained to [ziew]’s comment.
Take a look at:
https://developers.google.com/silicon
There will be new old stock for many years. And there are plenty of used chips, as Z80 was quite common, not only in home computers. And there are all those clones and variants. And if one doesn’t care for hardware, there is always a FPGA implementation for chip itself, or for the entire computer…
“Heh, well, won’t be “all new” for much longer considering the Z80 is unfortunately finally out of production.”
Zilogs version, yes. In DIP format, yes.
How about other manufacturers? There wasn’t just one Z80, after all.
Also the sound chip – AY-3-8912. It isn’t being made for years. The one that is being inserted in the video is from year 1991 …
https://en.wikipedia.org/wiki/General_Instrument_AY-3-8910#Variants
“The Winbond WF19054, JFC 95101 and the File KC89C72 have the same pinout as the AY-3-8910 and are also 100% software compatible.
They’re still in production and used on many slot machines.”
Not sure if that info is still up to date, but the AY-3-891x had clones, at least. Like Zilog Z80 used to have.
If no new AYs are available anymore then replacements like SID replacements might be needed.
Alas, the eZ80 is not compatible with the ZX Spectrum because it uses some I/O addresses for its own use.
Then there was the SInclair QL. Much more lucky with the processor and the upgrade boards. But unforunate in the market compared to the ZX.
Why use all that discrete logic? I understand that the original ASIC is not available anymore but why not just put all that logic into a nice programmable chip of ourself? Or is that part of the charm?
Username checks out.
Yeah, let’s just run an emulator and call it a day.
And it loads games even faster.
And you can save and reload where you want in game.
And it’s portable (in case of phone or notebook).
There are other applications that need an physical interface, though, which is hard to emulate.
Such as a morse code application that reads from MIC in or uses EAR for output.
Or an interface for an robot arm or a drawing tablet.
Back in the 80s, the ZX81 and Spectrum were not just for games but also affordable computers for the electronic hobbyist/hardware hacker.
I feel that if the Uncommitted Logic Array chip can be sensibly replaced by a CPLD or the like, it doesn’t go against the spirit of retro style hardware with modern parts IMHO – if FPGAs were available in the early 80’s they would probably have used that rather than a ULA which is in a way very similar except for not being “Field Programmable”.
I have an Agon Light 2, and that’s got an ez80 and esp32 in it, so a it’s more of an homage rather than a reproduction, but I would have certainly liked a retro style case with keyboard to house it in, just for the feels.
The problem with CPLDs, PALs and GALs is that they had been used excessively on vintage hardware and now start to fail, rendering precious pieces into scrap metal.
On top of that, they’re usually being copy-protected by setting an appropiate bit, making duplicates very hard
So it’s just natural that retro fans do have some aversion against them and won’t like to use them.
Open hardware projects are most homebrew friendly without relying on proprietary code. Pure hardware solutions without secret sauce, without black boxes, so to say.
That awful keyboard the Z80 had… I´m glad this modern version has a decent one!
Wow, I feel very privileged to have this shown here, thanks for the support Hackaday!
Needs these keycaps so bad! https://www.aliexpress.com/item/1005006004732837.html
They would be the ones to get for a new speccy, they look great.
HI, I designed the Mechtrum and these keycaps do not have some of the special keys needed like break and symbol shift, but I have just purchased a set to see what they are like. This must be a new batch because I have tried to get some for a while.
“COUNT” lol. One letter too many…
Is possible change firmweare/bios/rom ?
For example makinga a GPU or faster memory, adding gpio or joistick directly
Please check my project:
https://hackaday.io/project/190345-isetta-ttl-computer
This computer runs ZX spectrum games. It has no microprocessor and no ULA. It also runs 6502 programs.
Uses a VGA monitor and PS/2 keyboard.
The used memory and TTL IC’s cost about 45 Euro. It only uses new parts.