Zilog to end standalone sales of the legendary Z80 CPU

Production of some models of Z80 processor – one of the chips that helped spark the personal computing boom of the 1980s – is set to end after an all-too-brief 48 years. That sad news was delivered last week in an End of Life/Last Buy Notification [PDF] from Zilog. Microbee Logo Travel back to the 19-Z80s READ MORE Zilog …

[Andy 73]

Not fade away...

There are still new Z80 based kits being made for hobbyists and enthusiasts to build and learn about microprocessors. Build a MicroBeast or RC2014 and you can play Zork or run CP/M, write your own operating system or just enjoy the blinkenlights. Though the chips appear to be reaching end of life, it's expected they will be available (and useful for simple computer projects) for some time yet.

[Spazturtle]

Re: Not fade away...

There will be clones once stocks get low and Zilog's own eZ80 is binary compatible with Z80 code.

[Dan 55]

Re: Not fade away...

Maybe some adaptor board can be made to convert a DIL socket to a square socket for a Z180 or Z280.

[Andy 73]

Re: Not fade away...

Sadly the still in production Zilog chips (eZ80, Z180 etc.) are not hardware compatible with the original microprocessor.

[Dan 55]

Re: Not fade away...

Shame. I know the eZ80 is more like a SOC, but I thought perhaps the Z180 or Z280 could be persuaded to work even if the pins going to RAM > 64K are connected to nothing.

[Dan 55]

Re: Not fade away...

Seems it might be possible after all.

[Hoagiebot]

Re: Not fade away...

Sadly, all Z180 and Z182 CPU's are being discontinued at the exact same time as the Z84C00 (Z80) family. Here are the EOL/Last Buy notifications letters from Zilog for them:

https://www.mouser.com/PCN/Littelfuse_PCN_Z8S180.pdf

https://www.mouser.com/PCN/Littelfuse_PCN_Z80182.pdf

FYI: The Z280 was discontinued in the mid-1990's, so that ship sailed long ago.

[BartyFartsLast]

They'll be around for a long time yet, I must have several dozen just stashed in the various "it'll be useful" or "too good to throw out" collections of stuff I've got and I was never really a Z80 fan, much preferred the 6502 for no real reason other than it was the CPU in my first computer.

[ldo]

8-Bit Wars Redux

Back in the day, some were fans of the Z80, while others swore by the 6502. The latter pointed to how their favourite chip could do so many things in a single clock cycle, that the Z80 took several cycles to match.

What they neglected to mention was that the 6502 was doing these single-cycle operations on strictly 8-bit quantities, where the Z80 was trying to support full 16-bit arithmetic in all its addressing. For example, the 6502 was limited to a 256-byte stack that had to reside in page 1, while the Z80 had a full 16-bit stack pointer, the same size as all its other address registers.

[Paul Crawford]

Re: 8-Bit Wars Redux

The Z80 also had an alternate register bank, for interrupt handling swapping to that was far faster than pushing the registers on to the stack and popping off after the ISR had run.

[Anonymous Coward]

Re: 8-Bit Wars Redux

Kind of an early RISC vs CISC battle. The Z80 had some pretty complex instructions, while the 6502 kept it simple.

[Mike 137]

Re: 8-Bit Wars Redux

"while the 6502 kept it simple"

and was therefore the ideal first introduction to machine code -- maybe slower at math than the Z80 but quite fast enough for many purposes. In my day I built several sophisticated data logging and control systems using the 6502.

[Groo The Wanderer]

Re: 8-Bit Wars Redux

I'd have to disagree there. Because it's operations were orthogonal (all supported the 16 bit address space), it was a better educational platform for the logic of computing and the infant technology boom to come. I programmed both Z80 and 6502, PDP-11, and knew the machine sets for a couple of military processors whose compilers produced erroneous machine code that had to be fixed by hand before execution (YUK-502, I'm looking at you! *LOL* Couldn't even get division right, and that machine had no stack. Hunt down the documentation if you're curious how machines ran before someone developed the idea of a "stack" for them.)

[Anonymous Coward]

Re: 8-Bit Wars Redux

The real difference in the 8 bit wars came from the accessories around the CPU rather than the CPU itself. VIC-II and SID were very potent tools for the jobs they did. Doing those jobs in CPU would be both wasteful and poor performing.

I've lightly dabbled in assemblers for both systems. While architectural knowledge will send you different directions to problem solve, the capabilities are roughly par. Software racing scenarios are a thing. Pick a problem that one CPU is better at than the other and you win that race - rather predictably!

Group B rally car in the mud? Or Formula 1 car on tarmac?

I had both a C64 and a ZX Spectrum in the 1980's. One failed due to a badly placed glass of lemonade and we got the 64 the year after. There was no question for me whatsoever which was the better gaming system. But for tinkering, the accessibility of the Spectrum definitely won. All those peeks and pokes to do fun stuff on C64 condensed down to a few trivial commands on Spectrum. Middle-aged me knows the 64 is more potent but the instant gratification of programming the Speccy set me on a career path that obscure pokes could never have done.

RasPi started out with some bold ideas about opening up accessibility to Cambridge Uni prospectives; and then we get things like Scratch coming out. I was video called by my 8yr old godson the other day who had just wrote his first program in scratch with sprites responding to his whims. If it has created that spark, then it has done well. Z80 did it for me (with some help from Sir Clive and his team).

[John Riddoch]

Re: 8-Bit Wars Redux

The C64 had better sound & graphics, but I recall it struggled with 3D. The game "Driller" (an early 3D first person game) apparently struggled on the C64.

Tinkering on the Spectrum was very helpfully enabled by the manual which went into great detail about the innards of the system. It probably drove me into computing the same as yourself.

[Anonymous Coward]

Re: 8-Bit Wars Redux

The Freescape engine (Driller, Total Eclipse, Castle Master. Maybe a few other titles?) required a ton of patience on any of the 8 bits. Played most of them, but sub 1-FPS was not unusual while moving.

The Sentinel demonstrated somewhat smooth rotation, but movement by transferring from one robot to another could take quite some time to carry out. Can you hear that jingle playing with the blue screen for several seconds?

F16 Combat Pilot was decently smooth, with the 3D objects moving relatively smoothly even if they weren't on screen that often. Sprites were king really. 3D needed the extra bandwidth and megahertz of the 68000 or similar to really make an impact.

[Dan 55]

Re: 8-Bit Wars Redux

I imagine the Z80's 16 bit arithmetic also helps with Freescape. You can also turn the CPU speed up on a Spectrum Next or an emulator so the game renders faster and unlike many games the clock countdown still works properly.

[Robert Carnegie]

Re: 8-Bit Wars Redux

"Last night I dreamt I played Sentinel again"... no I didn't, but I was reminded of it recently, maybe here? That sinister buzzing noise as energy was sucked out of you and materialised elsewhere on the 3-D game board as trees (strange game). And yes, very, very, very slow on a complicated level - on my ZX Spectrum. Quite slow on a 6502 CPU BBC Micro, too.

[BartyFartsLast]

Re: 8-Bit Wars Redux

"The real difference in the 8 bit wars came from the accessories around the CPU rather than the CPU itself. VIC-II and SID were very potent tools for the jobs they did. Doing those jobs in CPU would be both wasteful and poor performing."

The custom chips definitely gave Commodore the edge and gave the, arguably, slower 6502 the freedom to fly, plus their ownership of the chip making facilities helped too.

No matter how awesome competiing products were they were either horribly expensive or cost cut in the extreme at expense of performance and reliability, the BBC Micro was never cheap and the Spectrum for example using QC fail RAM chips (cleverly but even so).

Commodore hit the sweet spot of price/capability and owned the market.

[prandeamus]

Re: 8-Bit Wars Redux

Although I believe the Z80s internal ALU was 4-bit, which just goes to show the tradeoffs that were made in those early days. That doesn't invalidate your point, to be clear. As a long-time 6502 developer there were times I would have killed for 16-bit registers and a stack that wasn't limited to 256 bytes. Or more than three on-chip registers. Or an increment instruction for A that didn't require you to clear the carry flag first (and so on).

It all prefigures the CISC/RISC architecture wars. Z80 was closer to the CISC camp, and some aspects of 6502 were quite RISC-y. (And before the purists peck my eyes out, I'm not saying that 6502=RISC in a strict sense).

The processor I really enjoyed writing code for was the 6809, but I didn't have many opportunities to do so. Oh, nice addressing modes and a consistent design!

[vtcodger]

Re: 8-Bit Wars Redux

Indeed, writing code for the MC6809 was a pleasure, unlike coding for anything Intel compatible.

[Jason Bloomberg]

Re: 8-Bit Wars Redux

I started out as a developer using 6800 and really couldn't see the appeal of the 6502. Though I used it courtesy of the BBC micro I never had any love for it. I could however see the appeal of the 6809 and Z80, especially with the latter having support for DRAM.

By the time I would have been using those the 8080 had become a thing and the rest was history.

[Anonymous Coward]

Re: 8-Bit Wars Redux

uuurrrggghhhhhh I remember trying to learn assembly on the 6502 at college c1987 BTEC electrical engineering

[The Oncoming Scorn]

Re: 8-Bit Wars Redux

You obviously weren't at Swindon (North Star) College where Mr Kerniski (IIRC or Chernobyl as he was swiftly renamed) had a fixation for Motorola 68000 & during long (invariably raining) 4 hours Wednesday afternoons we were left trying to follow his Polish accent, trying to stay awake (Some of us had decided a Icon lunch visit was beneficial after the first few weeks) & wait for the inevitable trigger of him waxing lyrical about partial address decoding.

[frankvw]

Re: 8-Bit Wars Redux

Motorola 68k? Been there. I attended Technicon in Rotterdam where the local Party Line was all about the Motorola 68000 and VME bus. Which, apparently was The Future at the time. It didn't take me long to realize that many teachers simply remained stuck on the last bit of technology they'd encountered when they washed out of corporate business and simply kept teaching that for the rest of their careers.

It's probably a testimony to their teaching qualities that I never could see the advantage of the 68k at the time. I do now.

[TRT]

Re: 8-Bit Wars Redux

I found the 6502 relatively straight forwards. Maybe I just didn't have much ambition?

[ldo]

Re: I really enjoyed writing code for ... the 6809

Not the 68000 family? Or was that after your time? Now there was a nice instruction set, clearly inspired by the DEC PDP-11. Very popular among the Unix workstation crowd, until RISC came along and wiped the floor with everything else.

[juice]

Re: 8-Bit Wars Redux

Back in the usenet days, there were some friendly "debates" (occasionally descending into tongue-in-cheek flamewars) between comp.sys.sinclair and comp.sys.cbm, around the capabilities of each chip. And on a few occasions, people broke out bits of code for a performance face-off.

And if memory serves, the 3.5mhz Z80A in the humble Spectrum did manage to be a bit faster than the ~1mhz 6502 CPU in the C64[*]. But it was generally in the order of 10%-20%, despite the Z80A nominally running over 3 times faster.

Then too, most of the machines which used a 6502 CPU generally had a bunch of support chips to help with the heavy shifting of things, whereas the CPU in the ZX Spectrum pretty much had to do everything.

But still, this all just added a bit more spice to the flame wars ;)

[*] As with most hardware at the time, machines configured for the PAL market ran a bit slower, because the CPU's clock was tied directly to the screen refresh mechanism. In this case, NTSC machines ran at 1.023 MHz, while PAL people were stuck with a meagre 0.985 MHz...

[frankvw]

Re: 8-Bit Wars Redux

I seem to remember that in those days many of those "religious" discussions confused CPU performance with system performance. It shouldn't have: the ZX80/ZS81 was based on 4 chips: the Z80, a RAM chip,a ROM chip and a custom-made ULA made by Ferranti. (Which we would now classify as a bipolar ASIC and probably replace with an FPGA). Try that with a 6502. :-)

[Tron]

Re: 8-Bit Wars Redux

The ZX80 had a lot more than 4 chips. One of the most interesting aspects of the ZX81 was that, just one year later, the logic chips were replaced by a single ULA (the screen display was fixed, and tonnes else). And then we got colour and a huge amount of RAM in the Speccy. If tech had continued to advance at that rate, we would have replicants by now. Instead we have Windows 11.

[Doctor Syntax]

Re: 8-Bit Wars Redux

AFAICR the 6502 memory mapped peripherals while the Z80 (and, I suppose, the 8080) had a separate peripheral address space that didn't require gaps to be left in memory with INP and OUT instead of PEEK and POKE.

[werdsmith]

It’s good to see the Zilog name is still out there. It’s been through a few different owners by acquisitions a management buy back and a chapter 11. Now owned by Littlefuse.

[Neil Barnes]

I was recently given to understand - I haven't been able to check so take this with a grain of salt - that Rochester are able to supply so many EOL parts because they buy the masks for those parts and remake. If this is indeed the case, it's possible they may end up with z80 parts available in proper 40-pin DIP packages...

(The 6502 - as the WDC65c02 - is still available new, though only from a handful of vendors - Mouser and Jameco are the largest, I think).

Hobby computing is becoming increasingly difficult (at the 'build a system' rather than 'program a system') due to the decreasing availability of easily prototypeable parts - SOIC is perhaps the smallest package that most people would be able to hand-solder; DIP is a lot easier. I've just designed a solderable prototyping board that will accept with DIP or SOIC for many parts, for my own development needs.

[elsergiovolador]

SOIC is perhaps the smallest package that most people would be able to hand-solder;

Microscopes and hot air stations are fairly cheap these days. With that, you can even solder BGA chips "by hand".

Long time ago, comments like this discouraged me from even trying like "this is SMT so can't be reworked at home". Turns out it can be and it's fairly easy.

It's actually much easier and quicker to work with surface mount components than THT.

[Neil Barnes]

In many ways yes, though I don't trust BGA without an x-ray inspection system which for some reason I don't have at home.

However, it's difficult to prototype circuits or parts thereof; effectively, you need to either make a PCB for the whole circuit or do something like an adaptor from the small-format part to DIP or similar. My most recent adaptor is from a TSSOP-48 ZIP socket to DIP-28 (so a larger but much cheaper flash part can be used to replace an olde-worlde eeprom).

PCB + solder mask + toaster oven seems to work quite well (though I wouldn't recommend it for production!)

[elsergiovolador]

If something doesn't work quite right, I reflow it and try again if still doesn't work, I solder new component again. If still doesn't work, perhaps there is problem elsewhere.

Prototyping is indeed tricky, but you can make breakout boards or see if some parts already have those from manufacturer or done by 3rd parties.

[that one in the corner]

> Microscopes and hot air stations are fairly cheap these days. With that, you can even solder BGA chips "by hand".

> It's actually much easier and quicker to work with surface mount components than THT.

Whilst that is no doubt true, for SMT to become easy to work with you need to move on from " a soldering iron and temporary use of a flat surface" to, as you describe, a proper work cell.

For the casual constructor, SMT is a PITA and it is quite a jump, even now with PCBWay etc, to get into diy'ing a circuit, compared to a bit of strip board or a through-hole kit (with all the SMT pre-done). Speaking as someone whose desk always has a soldering iron and helping hands stashed next to the keyboard.

[Electronics'R'Us]

Masks

I have never used Rochester for that (and I have used them a lot). I don't think they actually buy masks but buy up all available stock at LTB.

There are die banking services available where certain companies have relationships with the silicon vendor. This is very prevalent in avionics where kit has to be available for a lifespan of (often) 40 years or more.

[Anonymous Coward]

I could say "I did not see that one coming", though 48 years has to be some sort of record for any kind of complex IC production. I think only the 555 timer can compete for longevity? I still have hardware with Z80's in connected to my daily driver, namely a Roland SC-88.

Lifetimes and careers have been defined by the Z80 IC. I started out on the Sharp MZ-80 and later ZX Spectrum+. Would definitely not be doing what I am today without what it taught.

[DJO]

I think only the 555 timer can compete for longevity?

NE555 was introduced in 1971, the 741 op amp predates that by 3 years.

The 78nn series of voltage regulators are close being introduced in 1972.

The 70's were interesting times for component development.

[werdsmith]

The LM101 is even earlier than the 741.

[Mage]

PIC series?

Is the PIC 16xxx the oldest mpu architecture still in new chips?

And it doesn't even have a proper stack!

[Locomotion69]

MSX

Do not forget all the MSX computers in those days - all Z80.

Fond memories :)

[Fading]

Re: MSX

And the now 40 year old Amstrad CPC464.....

[AndrueC]

Re: MSX

Thanks for reminding me. I had a 6128 and loved playing around with bank switching. It was also a very well designed and written BASIC - thanks to Locomotive Software. I mean how many BASIC variants offered interrupt driven programming? Admittedly the architecture meant that it wasn't very accurate (the timers paused when accessing the disk drive or waiting for a string to be entered at the keyboard) but it worked :)

40 years ago. JHC. I was at Polytechnic when I had my 6128. Learnt BCPL and C on it as well as BASIC.

[TheFifth]

Re: MSX

I was flicking through a CPC 464 manual the other day and had lots of "oh, yeah!" moments as I remembered all the programming I used to do using Locomotive Basic. Definitely one of the best basics available on any 8-bit micro. I know everyone raves about BBC Basic, and it is really great, but I don't think the CPC's basic was far behind (and possibly ahead in some areas). The timers were something that really stood out to me when rereading. I had forgotten all about them.

I remember I wrote a poker game in basic on my 464. It had an 'AI' (not really) computer opponent and everything. OK, graphically it was simple, but I remember 13 year old me being very pleased with it. I really wish I had held on to those tapes and disks, however they were sent to the tip when my parent's moved house whilst I was at uni. Didn't think to ask for them to be saved. I was more worried that my Mum had given all of my Star Wars toys (a Millennium Falcon, an At At and loads of figures) to my cousin!

[Anonymous Coward]

Re: MSX

Ah alas I was not as smart as you, I remember typing out code for a Mandelbrot Generator found in a borrowed copy of Amstrad Action. After what must have felt like hours of index finger keying in, I recall being amazed at the rendering, which went on for hours. I really thought I'd achieved something, but the code made absolutely no sense - I guess at that point i came to a unwelcomed realisation that programming wasn't for me !

[AndrueC]

Re: MSX

To be fair a Mandlebrot Generator is mostly maths and thus unusually hard to understand. It's something of a myth that you need to be good at mathematics to be a computer programmer. For most projects you don't anything more than what I would call arithmetic. If you can add up a bill or work out your monthly disposable income your maths is good enough to cover most programming projects.

Modern languages offer several features to reduce the amount of maths needed. When I started if you wanted to iterate through a list of objects you had to create a loop, specifying the start index, the increment and (most troublesome) the end value. Modern languages now offer foreach which has significantly reduced the occurence of fence post errors.

[WurliMonkhaven]

Re: MSX

Oddly, as someone who is absolute trash at maths, I found my own Mandlebrot implementation (ASCII in a .NET CLI) pretty easy. Ya just gotta remember the song!

"Just take a point called Z in the complex plane,

Let Z1 be Z squared plus C,

And Z2 is Z1 squared plus C,

And Z3 is Z2 squared plus C,

And so on,

If the series of Z's should always stay,

Close to Z and never trend away,

That point is in the Mandelbrot Set!"

The maths is honestly super easy to implement. Don't let the mathsy words trip you out. Complex plane for a programmer usually just means "X/Y plane", for example.

[Anonymous Coward]

Doesn't Forty Years Flash By????

Ah.....the useful books by Rodney Zaks and Lance Leventhal!

And the fantastic book by David Cortesi ("A Programmer's Notebook").....which had multiple chapters each with the same structure: requirements, design, code....8080 assembler.

These were the resources I used to get started in programming in 1983.....on an Osborne 01......powered by a Z80!

[Duffaboy]

If it wasn't for the Z80

I would not have had a 35year career in IT. Thankyou Zilog

[werdsmith]

Re: If it wasn't for the Z80

Me too, but more thanks to Clive Sinclair for putting it inside a device that was within my financial reach.

[Gene Cash]

Re: If it wasn't for the Z80

I got my TRS-80 Christmas '79, which was almost 45 years ago.

The "expansion edge connector" at the back was some PCB traces extended past the reset button. When fumbling for the reset button, I discovered these traces connected directly to the Z-80, no buffer chips, nothing to protect it from static. I then discovered that TRS-80 warranty returns came directly out of the Radio Shack store's income, so the store manager was as distraught over the machine's demise as I was.

[Doctor Syntax]

Re: If it wasn't for the Z80

My boss got a TRS-80. I build him a joystick controller based on a Steve Ciarcia (I think) article in Byte.

[StargateSg7]

Re: If it wasn't for the Z80

Now THAT is a name i haven't heard of in a while! Almost every 1980's era Byte issue had him making a project. My favourite Steve Ciarcia article was making a DIY EGA graphics card! I tried it and got it working for a week before it died. I was quite proud of that DIY assembly work! I was tickled pink at seeing the LELA test image show up onscreen!

My troubleshooting skills were quite limited back then, but then again, components were big enough that you actually COULD make a home built graphics card at 640 by 350 pixels at 256 colours and it would work in my PC-AT compatible computer which i think was a "PC's Limited" brand which later became Dell.

Those were the days of easy computer component DIY! Oh Yeah!

V

[Michael Wojcik]

Re: If it wasn't for the Z80

"Circuit Cellar" was the name of Steve's column in Byte, wasn't it? I think it was eventually spun off into its own magazine — memory says Circuit Cellar Ink.

I did a few of Steve's projects, some with my father. The surge-suppressor, the light pen for the IBM PC which plugged into the cassette-deck port (yeah, we had a PC old enough to have the cassette port), the mod to the CGA adapter to make it grey-scale¹ rather than color. Maybe some others. Even if I didn't build whatever he was writing about, it was always interesting.

I miss Byte. Along with Dr Dobb's Journal it represented for me the height of popular tech magazines. Particularly in its heyday each issue was crammed with interesting stuff. Even the ads were often worth reading.

¹Or green-scale, in our case, since we had it hooked up to a green-phosphor monitor. Dad was a mainframe developer and he knew what he liked.

[Doctor Syntax]

Re: If it wasn't for the Z8000

The Z80's offspring in my case. Plus Unix and Marathon.

Marathon?

It changed its name.

No, not that Marathon and that name change. This was a bit more sensible. It became Informix. That's how I side-stepped Oracle.

[Christoph]

I was running complicated factory machinery using hand-crafted Z80 assembler. It all fitted into about 20K, most of which was screen & keyboard control. Then there was a data table listing all the ports for the components, which the index registers scanned through each cycle. The actual operating code was very small except for the most complex components.

[AndrueC]

Over the years I owned or used: two ZX Spectrums (Rubber thumb 16k then the later slightly improved 48k version), a CPC 6128 and as my career started several Huskys.

A few years later I discovered that Adaptec's 1542 SCSI card had a Z80 on it but I'm still not sure what for. Presumably only to marshall SCSI commands and responses from something faster.

It was also the controller for a 3.5" floppy disk autoloader I had to program once. We really only needed two functions - insert and eject - but when I discovered the Z80 stuck inside this horrible device I decided to implement code for all the sensors as well. Imagine the horror of being stuck inside such a boring lump of machinery. At least I gave it some kind of outlet to express itself :)

[The Oncoming Scorn]

Not unnaturally, many lifts imbued with intelligence and precognition became terribly frustrated with the mindless business of going up or down, experimented briefly with the notion of going sideways - as a sort of existential protest - demanded participation in the decision making process, and, finally, took to sulking in basements.

At this point a man called Gardrilla Manceframe rediscovered and patented a device he had seen in a history book called a staircase. It has been calculated that his most recent tax bill paid for the social security of five thousand redundant Sirius Cybernetics Workers, the hospitalisation of a hundred Sirius Cybernetics Executives, and the psychiatric treatment of over seventeen-and-a-half-thousand neurotic lifts.

[frankvw]

Pure vintage awesomeness

I cut my teeth on Z80 assembly with my ZX81, and I loved it. My fellow geeks (a.k.a. class mates) were all in the 6502 camp. I never understood why, because the Z80 was, in my humble opinion, the dog's whatzits and definitely the best CPU of the era. It was technically an 8 bit CPU, but the BC, DE and HL register pairs could be used for 16-bit operations as if you were running code on a "true" 16-bitter. Then there were nuclear-powered instructions like LDIR and LDDR that could transfer massive amounts of data across your entire memory map in just 4 steps: set source pointer, set target pointer, set block size, and let rip. Compare that to the puny two 8-bit registers X and Y (not counting the 8-bit accumulator register that the Z80 also had) and the fact that the instruction set lacked all the power toys from the Z80, which meant that instead of a few instructions you needed half a page or more.

My 6502-oriented friends saw it differently. I never knew why. They claimed a smaller instruction set was so much more efficient. Uh-huh. This was in the days when we still counted the clock cycles required for each opcode to work out timing and such, but while the Z80 required more clock cycles per opcode than the 6502 did (a fact that was pointed out to me over just about every cup of coffee) the much more powerful instruction set meant that even both CPUs ran at the same crystal-bound Mhz speed, the Z80 consistently won, and then some. But when I pointed that out their argument became that Jobs & Woz never would have chosen the wrong CPU, and the fact that the C64 sold more units than the ZX81, so the 6502 had to be better. Wimps. :-)

And then the peripheral chips! The SIO, PIO and CTC could be added to the Z80 with little more than a few paper clips and some snot, and suddenly you had yourself the makings of a very decent CPU-based microcontroller! And in true Zilog fashion, working with the PIO, SIO and CTC simply meant shoving some data into a bunch of registers and the rest took care of itself. Doing the same with a 6502 required a bucket full of TTL chips. (Of course this was before FPGA came onto the scene; back then you either did things in "dumb" 74xx/4xxx TTL/CMOS logic, or you used a CPU and software.)

I can see why the Z80 remained in production for 48 years. Although, in all fairness, the 6502 is also still in production, so honor where honor's due.

But no matter. With today's kit building a Z80 emulator isn't that complicated. Emulating a 6502 is even simpler.

[Anonymous Coward]

Everything old is new again

Until it isn’t

[Caver_Dave]

The things we did with a Z80!

"I was running complicated factory machinery using hand-crafted Z80 assembler."

I raise you with 64K of assembler used for F1 timing systems, including speed trapping, and a second EPROM partially switched into the address space when required to gather the text in your language of choice (1 EPROM was in English, the other in French)

[werdsmith]

Re: The things we did with a Z80!

I also worked on early F1 telemetry a long time ago. It was a 1 lap burst of stored recorded data when the car passed the pits.

I was chosen to help with this because I was (am) a licensed radio amateur who messed with RTTY. Thinking back it was a very Heath Robinson setup, unrecognisable for today's F1 engineers. But it worked.

[Caver_Dave]

Re: The things we did with a Z80!

Yes, I also did telemetry, but just sent the current readings over and over. (On the Pit Straight at Silverstone you could receive a whole 3 sets of information!)

This was for the Arrows Team in 1987 with Derek Warwick and Eddie Cheever as drivers.

It turned out that their ECU sent the information all the time over a parallel port to the display on the wheel, which had a button to cycle through the displayed values. I just buffered the parallel port and fed the values through a parallel to serial converter (74 series chips) and into a radio module. Also very Heath Robinson.

For remote speed traps for all the teams (e.g. Hanger Straight at Silverstone back to the pits), I employed Yagi Urdu antennas at the Tx end; that was very naughty, but the teams just said that as they were F1, it wouldn't matter. Never did get a good signal through the trees at some of the European circuits.

[John Brown (no body)]

Re: The things we did with a Z80!

I glued some hall effect sensors under my Scalextric track in a couple places and wrote Z80 assembler to calculater scale speed between the sensors and the lap count on my TRS-80 clone :-)

Not quite F1, but it felt good to my 14 year old brain at the time. :-)

[Evil Auditor]

Ah, the good ol' times... Learnt assembler on the Z80. And later, when attempting to port a Z80-powered appliance to the then new Z380, decided that hardware design wasn't for me.

_{Btw, the Z380 isn't still a thing, is it?}

[deanb01]

Gameboy Z80

Slight correction to the article - the Gameboy CPU isn't techniclly a Z80, it 's a Sharp LR35902. Whilst it's Z80-like, it is severly cut down, lacking several key features such as the alternate register set, block instructions (LDIR, etc), 16-bit addition/subtraction and index registers (IX/IY). It does add an 'FF' page, which is a bit like 6502 zero page. Though the point made is taken. as stocks dwindle it will become more difficult to source known working parts to replace Z80s in Spectrums, Amstrads, MSX machines, and so on.

[FirstTangoInParis]

I/O, I/O ....

Having programmed in both 6502 and Z80 assembler (and a bit of 6809), the I/O on a Z80 beat the 6502 and peripherals into a cocked hat, and so easy to build controller boards with I/O. But then as others have pointed out here, the 6502 was easier to learn to program.

I've seen the NSC800 CMOS version used in military applications, no idea if that is still around.

Over on Substack there are some interesting history lessons on how the 6502 became so popular, basically because it was dirt cheap compared to Motorola offerings.

Definitely raise a glass to the Z80 and all the 8-bit micros we cut our teeth on ...... -->

[Christian Berger]

Strictly speaking it's their Z84 line, not the Z80 line

The Z84 are CMOS variants which are faster and use less power than the original Z80 chips while being pin-compatible. The original Z80 chips probably have been discontinued decades ago.

That's why you still get Z80-flavoured systems based on even newer implementations. The Z84 chips kinda are overpriced with the CPU alone selling for more than a whole 32-bit micro controller fast enough to emulate it.

[mark l 2]

I was pleasant suprised to read it had still be in production all this time, as I assumed that as newer more advanced CPU's came along Zilog would have ceased production a long time ago.

But having never knowingly owned anything with a Z80 CPU - my first computer being a C64, followed by Amigas before moving to X86 PCs. I didn't realise how far spread its used was outside of the 8bit micros of the 80's.

[heyrick]

Perhaps the most peculiar use for a Z80 I've seen...

...is to bolt it to a 24 bit DSP to create a cheap MP3 player. That it actually works, while still being, you know, a Z80, is surely a win for the Z80.

https://en.wikipedia.org/wiki/S1_MP3_player

[deanb01]

Re: Perhaps the most peculiar use for a Z80 I've seen...

Oh, I've got one of those in a drawer somewhere. Didn't realise it was based on the Z80!

[Caver_Dave]

Re: Perhaps the most peculiar use for a Z80 I've seen...

I put one in something resembling a tube of toothpaste with switches on the side and a speaker where the cap would be. (1986)

It was held in one hand and a combinations of keys would indicate a letter and at the word break, a text to speech chip would try to say the entered word.

It was fairly successful, but running the wires up your sleeve to a battery in your pocket was too much of a faff to make it commercially successful.

[Bebu]

Coincidentally...

Coincidentally today I was looking up info on the Z8000 and Z80,000. Different directions.

Looking at the comments - is anyone reading elreg under 60 years old? Seems like God's waiting room. I half expected Victor Meldrew to chime in at some point. :)

[Dan 55]

Re: Coincidentally...

We're all curmudgeons at heart no matter our age here.

[Robert Carnegie]

Re: Coincidentally...

I don't remember if or when there's been a reader's age census. Probably 20 percent of readership now is AIs, but they don't remember Sinclair and other home computers where you needed a cassette player and the family TV for a session. So the comments are mostly from people who do.

[Doctor Syntax]

Coincidently I saw it announced in another place that CP/M is 50 years old.

Memories of S-100, Z80 (and the video board had a Z-80A!), 8"" disks, SDOS (a CP/M close) and Microsoft FORTRAN.

[Groo The Wanderer]

Now I feel. The Z-80 based TRS-80 Model I, Level I was the first computer I ever laid my hands on, even briefly. Being 14, I tried to write Space Invaders in BASIC. Too slow. So I cribbed up graph paper of machine code and POKE'd it into memory. I got as far as displaying a welcome screen before I lost access because someone bought it from the local Radio Shack. And because the local store manager was tired of me sitting at his only display unit for hours on end.

Fun times. Nothing but ancient memories now...

[Michael Wojcik]

Yeah, while the Spectrum was no doubt the best-known Z80 machine in the UK, in the US it would have been the TRS-80 Model I and II. (The II, with its glorious 8" floppy drives, was a rarer beast, as was the Model 2000; and the CoCo used a 6809.)

I was lucky enough to eventually have access to all three of what Byte called the "triumvirate" of late-70s PCs: first the Commodore PET, then a couple years later the TRS-80 Model I and the Apple II. Wrote my first programs on the PET, and I had some affection for the 6502, but I did some assembly noodling on the TRS-80 as well. I used to have a book which had a complete assembly listing for an alternative OS for the TRS-80.

[Ashto5]

Amazing food tech just lasts

Look at the voyagers

Good engineered tech just does the job

Nice to be reminded of these great things

Now where is my phone as it needs to know where I am at all times and track my browsing

[StargateSg7]

And to think i'm using a single-chip 128-bits wide combined-CPU/GPU/DSP/Vector processor super-workstation running at 2 THz with about 50 PetaFLOPS of available integer, floating point and fixed point math processing power!

Vive la difference!

[bigphil9009]

Yawn

[anonymous boring coward]

I read somewhere that the Z80 was the last CPU whose design was hand-drawn on paper, and all in the head of one designer.

I might have read it here.

[david 12]

Wafer Foundry Manufacturer?

Zilog, which started as a fabless chip company, closed its Idaho fabrication plant in 2004, and move legacy products to X-Fab's Lubbock, Texas plant. (I think Zilog is basically just cashing out its business)

Lubbock is "transitioning" from "Consumer, Communications & Computer" (a declining segment for X-FAB) to High-Voltage Silicon Carbide, perhaps this is the result?

I know nothing of the details, not even if the Z80 was still manufactured in Lubbock.