Earlier this year Zilog stopped production of the classic 40-pin DIP Z80 microprocessor, a move that brought a tear to the eye of retro computing enthusiasts everywhere. This chip had a huge influence on both desktop and embedded computing that lingers to this day, but it’s fair to say that the market for it has dwindled. If you have a retrocomputer then, what’s to be done? If you’re [Dean Netherton], you create a processor card for the popular RC2014 retrocomputer backplane, carrying the eZ80, a successor chip that’s still in production.
The eZ80 can be thought of as a Z80 system-on-chip, with microcontroller-style peripherals, RAM, and Flash memory on board. It’s much faster than the original and can address a relatively huge 16MB of memory. For this board, he’s put the chip on a processor daughterboard that plugs into a CPU card with a set of latches to drive the slower RC2014 bus. We can’t help drawing analogies with some of the 16-bit upgrades to 8-bit platforms back in the day, which used similar tactics.
So this won’t save the Z80, but it might well give a new dimension to Z80 hacking. Meanwhile, we’re sure there remain enough of the 40-pin chips out there to keep hackers going for many years to come if you prefer the original. Meanwhile, read our coverage of the end-of-life announcement, even roll your own silicon if you want., or learn about the man who started it all, Federico Faggin.
“Earlier this year Zilog stopped production of the classic 40-pin DIP Z80 microprocessor, a move that brought a tear to the eye of retro computing enthusiasts everywhere. ”
Yes, but what’s easily being forgotten: The Z80 had been produced by a dozen other manufacturers, under license.
Intel did same thing with 8088/8088 and 80286 proccessors.
So Z80 isn’t dead per se. It’s merely so that Zilog stopped Z80 production.
Other manufacturers may continue producing their Z80 variants, which may be pin compatible or not.
To be precise, Zilog ended the production of the CMOS variant. The “classic” NMOS part was already phased out a long time ago. I guess it will take some decades for sources to dry up, there must still be millions of new units stocked as spare parts for industrial and military products. They will surface one day and will be sold for next to nothing by Pollin…
Pollin, lol. You’re right, though, I suppose. +1 😃
Pollig had (has) Russian tubes in the catalogs, after all.
Speaking of Russia and former UdSSR, the former GDR had made a Z80 clone, too, at some point. The U880.
And it wasn’t bad, at all. So if GDR can make a Z80 using antique production sites, so maybe can we eventually.
https://en.wikipedia.org/wiki/U880
“So if GDR can make a Z80 using antique production sites, so maybe can we eventually.”
Why should we? The Z80 was used in so many industrial appliances made in the past century, like PLCs, printers, displays, motor controls and what not. If I’d need a Z80 right now, I’d just dig thru the junk bin of the OT guys. Finding used Z80s is not difficult if you keep your eyes open, they are everywhere (except in Siemens gear).
“Why should we?”
I’m puzzled. I don’t understand that question. Why should we not ?
The Z80, along with the inferior 6502, was groundbreaking.
It literally caused the microprocessor revolution and the birth of the home computer era.
Along with niche designs, such as 6800 and 68000, of course.
And the older 8080, which it completely had replaced after release.
Being technically able to continue production independanly, on-demand, thas a value in education and homebrewing.
The Z80 used to be sort of a reference platform. The platform other platforms are being compared with (the 8085, too, but it was less interesting).
Being able to produce it freshly using current technology means that it’s more than just NOS (new old stock).
The Z80 is also heavily being used as a CPU core in emulation.
Making a Z80 core from scratch is an exercise to emulator writers, thus.
And if the “real thing” is still being available physically, an not just physically in the museum, it is much more interesting.
I’ve found this to be interesting: http://www.z80.info/sharp/z80_glas.htm
It’s from 2002. With current technology, I wonder what Z80 derivatives could be made.
I find all the possibilities to be really fascintating! 😃
Joshua,
don’t get me wrong, but the Z80 and its successors are as ubiquitous as BC238 transistors and EF80 tubes. There’s no point in recreating something that sits on shelves and can be pulled from trash in large numbers. It would be an immediate commercial failure, because the dwindling world wide demand for fresh “real things” wouldn’t even justify cleaning off the dust from an ancient production line. And you’d have to compete with refurbishers and surplus dealers. The more modern variants are also available en masse, a 33MHz Z180 in PLCC case (new, not pulls) can be had for less than 10€.
btw: today I found a couple of µPD72020 in the trash, now the BOM for one of my retirement projects is nearly complete. Industrial junk bins are a goldmine. ;) Also there were some controller boards from check weighers with NMOS 8085s, produced in 1999! That should serve as an example on how long ancient designs survive in industrial gear (and on where to look if you need parts).
@Hartl I do understand you and I do not understand you at same time.
You seem to be much better at being German than me, I’m afraid. 😅
Because I wasn’t thinking about practibility, money or availability, but I was thinking in a more, um, idealistic way.
I like to dream and think of an optimistic future. I’m a hopeless optimist, I guess, ha. 😅
Despite having to fight all the pessimists (aka realists) in real life surrounding me all the day.
I know I’m part of a minority, but positive thinking is what makes life worth living (to me).
And in this case, I just think it’s fascintating to be independant, to being able to build things in the shack all alone one day.
Today we have 3D printers, for example, which got a home in most homebrewers labs. A few years ago, this was seen as futuristic, still.
Lithography at home or lithography in a maker shop would be interesting. The Z80 would be one candidate among others.
The 6502 also has a low transistor count, too. Relatively speaking.
Being able to reproduce an 741 opamp or 386 amp ic, would make these chip immortal.
(NOS parts can age, too, through internal corrosion, by the way).
People in the future could rebuild vintage circuits just in same way we do 3D print vintage mechanical parts.
Also, it would give more power to the people, to the citizens.
In a democracy, this should be seen as a welcomed achivement, I dare to think.
Again, it’s not about practibility. It’s not about the parts in the parts bin.
It’s about being fascinated by technology and being able to discover, to learn new things. To be fascinated like a child if it sees a rainbow.
That’s why I had built audio amplifiers and other circuits using discrete parts intentionally, rather than using ICs.
It wasn’t about power efficiency or parts count, I wanted to see my circuit working right in front of me. I wanted it to come to life.
That’s why I have a facination for relay logic, too. You can watch things working.
And you can fix it, if it breaks (yes, I built myself a relay from scratch).
If I had a little water-operated vaccuum pump, I’d try to build myself an incandescent lamp or a radio tube, too.
It won’t be great in terms of function, but it would be an interesting excercise and and help me improving my skill set.
Maybe it’s because I grew up in an ham radio household, but I do value homebrewing and independance a lot. Hm. Is this desire really so strange these days? 😕
Being able to build resistors using wire, cheap capacitors using aluminium foil and paper or being able to make your own spider web coils is such an experience, I think.
It makes you feel traveling on the paths of old monks from centuries ago or something along these lines.
You know, these guys who did experiment and copy entire books by hands.
It’s a bit of a spiritual thing, all in all. Vy73s
The Agon Light was released in 2023 and is SBC running an EZ80F92 along with a ESP32 Pico handling graphics and sound. Cost about $53 fully built and tested https://www.thebyteattic.com/p/agon.html
They’re still actively working on the software too, I like it and own one, but I’d have loved HDMI and USB HID.
I’ve been looking at RC2014 boards on Tindie, it’s nice to see all that has been done, but I get the feeling that it doesn’t suit me well enough to buy into the system.
z80 fpga options?
Using 64 bit ‘software registers’ is it possible to do 64 bit integer arithmetic [+, -, *, /] with a 8 bit processor?
figForth 8080 programmers taught how to do 16 bit arithmetic on an a 8 bit platform.
And 32 bit on a 16 bit platform?
Carry bits existed from the very start.
As dog intended it…Semicolon!
I wonder if anyone has ever built a discreet transistor Z80 along the lines of the discreet transistor 6502 that exists…
Something that doesn’t seem to get mentioned much is that it’s not just the Z80 CPU that went EOL, but also the supporting peripheral chips like the PIO, SIO, CTC, etc. These are essential if you want to build an optimized Z80 system that actually runs right, and by that I mean uses Interrupt Mode 2, which is the most elegant way to interface the CPU with the peripherals.
You might be able to adapt an eZ80 to replace the CPU itself, but getting it to replace an SIO for example will be more of a challenge, and would require some very “inelegant” hacking to bypass all the original hardware designed to communicate the peripheral chip. At that point you might as well just throw out the whole Z80 system and use the onboard UART included in the eZ80. That’s fine if your goal is to modernize, but if the whole point is building an old school system or keeping it alive as originally intended, it’s problematic.
I agree. The Z80 SIO was especially important, I think.
It had been used (is being used) in CP/M systems and controllers such as TNC-2.
Alternatives used to be Z80 DART and the i8250 (ew).
The latter had often been used in 8-Bit x86 PCs and was known for being badly usable for higher baudrates (16550xx was a recommended replacement).
That being said, programming the SIO felt akward to some folks coming from the i808x ecosystem, or so I heard.
And the DART couldn’t do SDLC and HDLC modes, but what otherwise similar to a basic SIO?
The SIO has a steep learning curve but once you know how to use it it’s great. I found the PIO and CTC to be relatively easy to learn in comparison. My appreciation for the Zilog peripheral chips has grown immensely as I’ve gained more Z80 experience. One can always kludge non-Zilog chips and get a system to work, but the interrupt scheme won’t be as elegant. It defeats some of the performance advantages of the Z80.