The Z80 CPU - 1976 to 2024
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- Опубликовано: 20 июн 2024
- The Z80 CPU: Powering the Best Loved Home Computers and Consoles of the 80s and 90s
In this video, we take a nostalgic journey back to the 1980s and early 1990s, exploring the iconic Z80 CPU.
This video is sponsored by PCBWay, for high-quality PCBs and CNC machining, visit www.PCBWay.com!
This microprocessor was the heart of some of the most beloved home computers and gaming consoles of the era, including the Sinclair ZX Spectrum, the Amstrad CPC, the Sega Master System, and many more.
In this video, join us as we delve into the history of the Z80 as Zilog rolls the last of the chips off the production line some 46 years after its initial launch.
I talk about its architecture and its significant impact on the world of computing and gaming. We’ll uncover why this 8-bit CPU became a favourite among hobbyists and developers, and how it helped shape the early days of personal computing.
🔍 What you’ll learn:
• The origins, people involved and the development of the Z80 CPU
• Key features, performance and technical specifications
• Notable computers and consoles that used the Z80
• The influence of the Z80 on modern computing
• Fun facts and lesser-known trivia about the Z80
Whether you’re a retro computing enthusiast, a tech historian, or just curious about the technology that fueled the golden age of home computing, this video is for you!
Don’t forget to like, comment, and subscribe for more deep dives into the technology that shaped our digital world. Hit the notification bell so you never miss an update!
#Z80 #RetroComputing #HomeComputers #GamingHistory #TechNostalgia
00:00 - Introduction
02:23 - Part I: Federico's Foray
02:36 - The 4004, 8008 and 8080
04:53 - Zilog: The beginnings
05:34 - The Z80
07:41 - The 6502 competition
08:18 - Japanese copycats
08:59 - Part II: Z80 Machines we loved
10:36 - CP/M and the Z80 Softcard
11:22 - Part III: Performance
13:46 - Part IV: An enduring legacy
14:25 - Z8000 & Z80's legacy 
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I honestly thought the Z80 might never leave active production. What a great piece of technology history!
So finally after 50+ years the 6502 vs Z80 war is over, winner by default the 6502! 🤪😜
😂
good times... Z-80 was first CPU, I programmed in assembly.
Don't cry boys. Z80 is dead but Z180 and eZ80 still live on. Don't throw out your source codes yet.
Indeed, the eZ80 not only continues the instruction set (with 24 bit extensions no less) but does so at 50 MHz clock speeds.
Can you imagine whan an Amstrad CPC would have been like with a 50MHz Z80?:)
Fun part being that you could almost certainly STILL run CP/M on the eZ80. :)
Glad to hear about the eZ80 because the Olimex AgonLight2 uses it.
I am surpried that no credit is given to Ted Hoff (Intel employee No.12). Hoff came up with the idea of using a "universal self-contained processor" rather than a collection of discreet chips. He designed the instruction set for the Intel 4004 with Stanley Mazor in 1969. Development of the actual 4004 chip was done by Federico Faggin, as mentioned.
They are all credited with the invention of the Microprocessor.
I found this video fascinating and sad in some ways seeing at the same time seeing an old acquaintance retire but then again technology moves on.
From 1980 to 1987, I worked for Visual Technology. Visual used the Z80 almost exclusively in their terminal products except for one model that came out in early 1987 which used the 68K. In addition to their terminals, they also produced a couple of personal computers, with one being the V1050. The V1050 had both a Z80 for its main operations and a 6502 for graphics allowing the system to perform some amazing tasks and ran CP/M Plus.
As a technician, I knew the pinouts inside and out and while attending night classes towards my degree, I took a class in Z80 Assembly language which was offered at the time. As it turned out, the professor owned a Visual V1050 and I ended up repairing it for him when it crashed. For our class project, we used Apple II computers with that Z80 card installed. All it took was a simple key-combination that switched between Apple OS and CP/M 2.0.
Thank you for this respectful homage to a great idea; regardless of the z80 being their peak or not - It is most definitely valid to say that we owe Zilog a lot!
Thanks for the kind comment!
Many years ago I had a Heathkit H89 computer which used two Z80 cpus. One of the Z80s was on the main computer board, the other Z80 was on the video terminal board. This computer could run two operating systems. One of the operating systems was Heath Disk Operating System, known as HDOS. The other operating system was CP/M.
It could also run UCSD pascal, which was its own operating system with a p-code interpreter integrated into the p-System (the name given to the operating system). Capable of concurrent multitasking at a time when MS-DOS was strictly single thread. The performance of the H89 was, for the day, remarkably good. We used one in conjunction with an external box, to emulate a wide range of CPU's in hardware and driver development. Ultimately UCSD priced itself out of the market.
That sounds awesome. I've never heard of that system. You've given me something to research. Thank you 😉
There was another version of this computer. The kit form was called the Heathkit H89, the fully assembled version was marketed under the Zenith Data Systems name as the Zenith Data Systems H90. It is too bad the Heathkit and Zenith Data Systems went out of business.
@@davidgrisez I'll check that out as well. Thanks
@@davidgapp1457 It''s a shame because the p-system is inherently portable and could easily adapt to new cpus. SofTech dropped the product, and it was picked up by Pecan Systems, owned and run by real enthusiast users. But the market at the time wanted to coalesce around a single OS, just about any microcomputer OS might have been embraced, but IBM PC-DOS and MS-DOSes turned out to be that, although early MS-DOSes, were really a bunch of incompatible OSes. Compaq, Phoenix and the other clone makers fixed that.
I still have a Z80-powered clock, built from a kit. It picked up the 60KHz radio signal from Rubgy, UK. The signal contained the date and time from an atomic clock, and was sent as a fast data burst in the first second of every minute for equipment capable of reading it, followed by the same information transmitted as pulses at 1 second intervals for slower eqipment. It has no RAM, just an EEPROM with the code and a bunch of chips to drive a 6-digit 7-segment display. It's called the REWBICHRON, published in Radio & Electronics World back in the 80's.
I was genuinely sad when I learned that the Z80 was end-of-life. End of an era.
Cheer up, this is not an end of an era yet. Z80 is dead but eZ80 still lives on. Same instructions, better chip. And some small Chinese company might still pick it up anyway.
Wouldn't be too concerned. There are millions of Z80 based chips out there - including SoC versions of the Z80. In addition, you can emulate the Z80 in a FPGA (or similar) which yields a performance considerably superior to the stock chip. Personally, I bought one of the Spectrum Next Edition 2 which took me straight back to my first computer!
Lived with it for few years as a designer and liked it
Made a project when i was in the sixth form (1980-81) - disco light sequencer built around a Z80A. Hand compiled assembler into a 2716 UV EPROM. Hand drawn photo etched PCB. It eventually died when the NiCd battery leaked and ate the track!
I had a TRS-80 and often used EDASM (an editor and assembler).
You could do nice things with the memory-mapped display.
One thing I remember was a 3D game-of-life program I wrote in assembly.
At the time you could really fully understand a PC.
I soldered another 3 sets of memory on top of the 16 KB RAM and added an address decoder to create a whopping 48 kByte RAM.
Also a lower-case character generator as the base TRS-80 only had CAPITALS...
This is a brilliant documentary. Just to add, $26 in 1976 was roughly half a week wages in a ordinary job today. By ordinary, I mean somewhere between a retail worker or delivery driver. I still believe in the Z80
That's like 100 bucks in today's dollars. Retail pays around 15 bucks an hour. So its more like a days pay.
Thanks very much for your kind words! It was still a decent chunk of change, but certainly affordable compared to the thousands of bucks Intel would charge. Only after the success of the 6502 and Z80 did Intel & Motorola see that computers could be in every home and office and started to scale their prices accordingly
Love Z80 ❤❤❤❤❤❤❤❤❤
TRS-80 Model I / III were the first two computers I programmed on in the early 80s at school. Our family's first computer was a Kaypro II in early 1984. All of these beauties powered by the Zilog Z80.
My first system, and first assembly I learned. A rare 'Exidy Sorcerer' with rom cartridges and Kansas-City tape interface. Ahh... those were the heady days of user groups meeting in person to exchange cassette tapes of programs we'd spent hours typing in. :)
Same here. I was an active member of SUGT. Sorcerer’s User Group of Toronto! It was my first computer as well. I wrote the Trek77 game for it.
My first computer was a Cromemco Z80 system on an S100 bus, with 64K RAM and two 241K 8" floppy disks running CDOS, a CP/M clone. Later I upgraded to a (massive!) 10MB hard disk, and recoded the OS to support it - not too hard in those days, with just serial port and two disk drivers needed. That computer did a lot of work for me. Simpler times indeed!
That would have been a really cool experience! If you'd ever feel like having a chat about your machine on the channel, I think that would make a great story! Drop me a line if you would like that!
Please let us know more about this. We need to be able to record the stories you have in order to learn.
Lots of memories to dust off - I'll see what I can do.
I built a Cromemco Z1 kit for my college in 1978. Like your machine, ours had 64K RAM and two floppy drives. We used the machine in our computer science classes to study operating system design as our IBM Remote Job Entry system into an IBM 370 limited our ability to get down to the hardware level and write device drivers. Upon graduation in 1980, I joined Mostek and became a factory application engineer on the STD bus which was based on the Z80 chip family
@@mbilden I've summarised it, but its too long for a posting here (just over 2 pages). Any suggestions?
A great CPU...
... and there are so many of them that we can not run out in the next 50 years! :-)
Except the Z80 only has a 4-bit ALU and lots of its instructions are on one end of the clock tick. The 6502 has a true 8-bit ALU and it can process instructions on the top and bottom of the clock tick. If both at 1MHz, the 6502 far outperforms the Z80. That's the key isn't it, the Z80 was usually at 3.25MHz, 4MHz or some faster speed, so the Z80 seems better at first.
Yes I think that's why I said that the 6502 was better on paper. The Z80 outperformed it because it was provided at greater clock speeds than the 6502 at the time
Who cares perf/Hz? Who cares ALU width? Only perf/dollar matters!!
Lets double the lifetime of the Z80:
or a; clear carry flag
ld hl, 2024; this year
ld de, 1976; date of creation
sbc hl, de; HL = 2024-1976 = 48
add hl, hl; HL = HL *2 = 96
Yes, that *is* my idea of a joke, and no, I didnt need to look up the Z80 instructions
Being born the same year of the Z80 and growing up with 8 bits computers and arcade games I’m feeling old…
Me, same year, same feeling 😂
I was born the same year as Unix, about the same time as the equivalent of Unix 1.0. To really geek out, my birthday in Unix Time is in the low millions, but saying this doesn't make me very popular at parties for some reason
i still got my speccy from 82 and i feel... not old. irresponsible maybe.
I made a fully functioning emulator/debugger of Z80 on a PC in Borland Pascal back in 1994. Will never forget that good old processor.
Got the original zilog technical documentation for the z80. Need to review it and remember.
What a great video, thanks! And shared!
Congrats on this video's success! Any video that gets more views than subscribers is a win 🙂
I've become a fast fan of the Geek Lab and I'm stoked at your success!! Dude - yer a RUclipsr!!
You rock! Thanks dude!
Thanks for this super interesting video on an old classic!
That processor is the same age as me, I grew up with computers that use it, no wonder I love it!
Great video!
Thank you!!!
Lovely overview! Thanks it was very enjoyable!
Glad you enjoyed it!!
0:27 the shown TI89 is based on the 68K from Motorola. I believe only the TI84 series is powered by a Z80 derived MCU.
well, for that matter the GameBoy and probably others, are "Z80-derived" and not actually Zilog's chip. TI83 series also had Z80, and if you want to get really pedantic, the "TI84 series" is always referred to as the "TI84-Plus" series, in Texas Instruments documentation.The 83 got an upgrade to "Plus" and they kept "Plus" in the names of all the TI84s.
I built the Heathkit Z89 computer from a kit. It had the Z-80 and it was an AWESOME processor.
Great video! Thanks!
0:27 The pictured TI-89 actually used a 68000 but some TI graphing calculators do indeed use a Z80 (or an eZ80 these days).
Thanks for the heads up. I knew some of them did, didn't specifically know which ones
Yes , but all Texas graphic calculators before Ti89 used Zilog cpu
@@edwardteller5879 TI-81 to T!-86 used Z80, and so did TI-73. The earlier TI-80 used some weird Toshiba thing. TI-89, TI-92 and TI Voyage 200 used 68000.
@@ijabbott63 you forgot the T83 series and TI84-Plus series, unless I am misinformed. The first TI-80 Pocket Computer used two 4004s. Not in any sort of "dual core" set up or the equivalent, Sharp (these were re-branded by TI) just divided CPU functions between the two. This is the kind of fact that AI hallucinates on, I'm sure confusing The Pocket Computer with the other TI-80 microcomputer line. The Pocket Computer heavily marketed on it's ability to do BASIC, which at the time made it not a calculator, at least according to TI marketing and their literature, anyways.
@@squirlmy I was including the TI-83 and TI-84 series within "TI-81 to TI-86", also including the TI-82 series and TI-85. I was mistaken about TI's first graphing calculator was the TI-81, not the TI-80. The TI-80 graphing calculator came several years after the TI-81 and was unusual in not using a Z80.
I think you were thinking of the TRS-80 pocket computer.
Great video, man.
The Z80 is my favorite CPU alongg with the 6502. I've always wondered how fast they could be if more modern processes were used to make them, say 90nm or something. Of course the die would be so small that a very accurate tiny robot would have to package it, but they could get millions from a wafer.
They could indeed be wicked fast, but without intermediate internal cache augmentation or simply incorporating all system memory on-chip (yesterday’s system memory size is today’s cache size), it would spend vastly more time in wait state’s than execution.
The Z80 kicked off my career as a database developer: After stumbling around with Applesoft Basic on the Apple II, and its extremely limited functionality on Apple DOS 3.3, I got to try dBASE II on CP/M, with the Z80 softcard on the Apple II, and that WAS a breath of fresh air. A (somewhat) relational database, and a whole new world opened up and my career or getting stuff done.
Guess, what... I still have a few, brand new in their package. Great video !
Sega Genesis/Mega Drive had a z80 to act as a sound cc-processor and for backwards compatibility
Indeed it did, I could have spent a loooong time reeling off the many uses it had but I had to stop somewhere!
I fondly remember learning about the Z80 while at the Helena Vo Tech in Helena MT. Our instructor had an MITS Altair computer in class and told us that the Z80 was like the Intel 8080 but its instruction set was a superset of the 8080 and the Z80 was a big upgrade.
That it was! Hope you liked the video!
It’s in the Mega Drive/Genesis as well. Along side the Motorola chip. It handles the sound and since it’s the heart of the Master System also handles the backwards compatibility. It’s truly a legendary chip.
Thanks 👍
The shop I worked in (1976-80)sold the Exidy Sorcerer, a Z80 micro, around 1977/8. Not a bad computer, it had 16 or 32k of RAM, could load and save to casette and you could plug in ROM modules (a PCB inside an 8-track cartridge!) for word processing or BASIC programming; other applications were planned but I never saw one. Then it got a disk drive unit that took 100k floppies or even a little hard disk, but that loaded MSDOS instead of the cartridges and took almost all of the working memory, leaving about 1.5k. I did write a stock control system to fit, but I had to use random access files on the floppy, making it slow.
Museum piece now, of course.
A few years ago, I threw out my Jupiter Ace, another Z80 machine, on the lines of the Sinclair ZX80, running Forth. I now find that they change hands for hundreds of pounds. Some you win...
They should have gone 2 more years so we could celebrate 50 years of production.
Even the Tandy 2000 had the Z80B!
The Z80 is still going strong. Still working after all these years.
The Z80 will live on into perpetuity through its FPGA core. Love it, use it often. Yeah!
Its been quite a ride.
only its not the end, far from it :) dozens of Z80 clone variants are still produced by just about every semiconductor manufacturers, and will be produced essentially forever. this processor will outlive all of us.
Amazing, the venerable Z80 is as old (possibly to the day) as I am (though I personally have yet to be discontinued) - and just as an aside, the Sega Genesis/MegaDrive also had a Z80 as a co-processor alongside the Motorola 68000, used primarily for audio synth.
Still weirds me out, as a non-American, to hear it pronounced "Zee-eighty" (though I realize its inventors probably used that pronunciation)
That’s the main reason I prefer the 6502 and not the zed 80
The Z is a regular Z so you pronounce it as you normally would, I have no idea why my fellow Scot here is pronouncing it that way.
Was a 6502 kid myself. had some neat tricks of it's own with zero page address redirection saving many cycles to perform similar... also able to rewrite it's own code because of the shared memory space.
Don't get me wrong the Z80 was a beast... but I had to make do with what I had ;) The real issue was that neither Zilog or Rockwell were quick on the uptake of SOC so most of the first generation of embedded's ended up being 8088/6 devices. Dallas Semi took those and ran making some really cool ultra low powered devices with some exceptional low power static ram stuff based off of the 8051 architecture.
I am happy to say that I love the 6502 and Z80 equally 😍
They should open source it! Thanks for the video!
back in the late 80's - Early 90's, I had Basis 108 computer , that was an Apple II clone , that would run Apple Basic and CPM. I did alot of coding on it in apple basic, but sadly never learned CPM. I kick myself for ever getting rid of it 🙄☹ it was given to me for free from a friend , and now on E-Bay I see that they are very rare and by the listing I looked at, they now go for $$969.99 USD 😧😖
Only issue is the TI-89 you displayed as a Texas Instruments Graphing calculator doesn't contain a z80, rather a 68k.
My school had an apple2 with the z80 card ^^!
NASCOM 1 was a British SBC that used the Z89, 1k RAM, NASBUG the machine code monitor on PROM, real keyboard and TV modulator output.
Imagine if the Z80 were designed in state-of-art CMOS to have a clock rate of say 7GHz. Of course, you'd have to redesign the support chipset too. Since it's smaller, I bet you could run it at a higher frequency than most CPUs due to less overall heat production. But still wouldn't be too powerful compared to modern CPUs due to a lack of what I call "torque" i.e. how much work gets done/clock cycle.
Take a look at the Z180. It’s still in production, runs Z80 code, is CMOS based and runs at up to 32MHz.
The Z80 per se did not stop production. Just the 40 pin DIP plastic package version was discontinued for production.
❤
Great video! What resources did you use for your research? I don’t see any sources listed in the description…
Various sources, I don't have the script with me right now and I made the video over two months ago (it's been up on my Patreon channel a while). I believe some of it was Intel archives, computer museum, excerpts from interviews from Faggin and also Wikipedia where I could cross-check.
Do you typically not post them or will they be appearing later? I wrote a piece on the same subject and would be keen to expand on my piece with some of the other things you mentioned here. 😊
whaaattt ... not fair .. I was planning to get to get a Z80 in the future to help me learn electronics.. there's so many interesting books on them..
So there were still fabs around making chips on 4 micron? Im surprised the die hadnt been shrunk more over the years.
I've used so many Z80A's in the past for silly projects. You can have a lot of fun with a Z80A, a 1K EPROM, some transistors and a bunch of LED's.
A wonderful, fast and very capable CPU indeed. I miss those days.
I had one in my Dec Rainbow
I like to Increment the Accumulator !!
Ti 89 was actually one of the few non Z80 ti graphing calculators, actually had a motorolla 68000
Party on dude
Part of the Z80 family was the Z8530 Serial Communitcation Controller. A much better comm chip than is the Nation 8250 device that was the standard in the original IBM PC.
The TI Professional PC. (TI-PC) desktop computer used the Z8530 for it standard data comm controller.
What CPU architecture will be the first implemented in graphene? 6502, z80, risc-v?
I still have my MSX computer.
I'm surprised that Zilog never went after the potential performance benefits of switching for a full sized 8 bit ALU to the Z80. I guess while it would still be instruction-compatible, the timings would change, which could affect certain applications of the chips that had code reliant on many clock ticks each instruction used.
That’s exactly what follow-on variants did do, but they dropped out of the PC race and receded into the lesser known embedded world.
Interesting point, thanks for the follow up @chrissmith-tc4df too!
The Game Boy did *not* use a Z-80. It was an 8080 with extensions for bit manipulation that happen to match what the Z80 has, but the Z80 is so much more, plus more registers and another set of registers for fast interrupts.
The GameBoy (DMG) used a custom system on a chip (SoC), the DMG-CPU as named by Nintendo, and LR35902 by its manufacturer Sharp. This contained a Sharp SM83 as the CPU: a hybrid between the Intel 8080 and Zilog Z80, but strictly not either. Given the extensions were Z80 extensions to the 8080 it’s closer to the Z80 than anything else.
You've forgotten the Exidy Sorceror in your roll-call of late 70s Z-80 based home computers. It was never commercial in a big way & competed poorly against the Apple II, Commodore Pet & Tandy TRS-80. Exidy were originally a games manufacturer. I've still got mine! I hope it's worth a fortune! Also The MicroProfessor which was a little open electronic system designed to teach Digital Logic & Microprocessors. Oh Happy Days!
Z80 was faster at certain low level operations. But the 6502 ran rings around it running higher end stuff thanks to
its zero page addressing mode which gave it 128 sixteen bit registers.
Surprised you didn't mention the Z180. That was a super Z80 originally developed by Hitachi as the HD64180. Z180 was a very useful embedded MCU in the 90's
The Z-80 is still on life support in these binary compatible expanded architecture products.
Agreed. The HD64180 was an amazing chip with integrated Uarts, timers, etc, long before they became commodities in the microcontroller space.
I temember the Z80 card for the apple II.
In the Introduction, what about the 1.5m ZX81s sold?
Your storey of the Zee 80 sounds a lot like the story of the Zed 80. Are they related?
Given Zilog is an American company it should be pronounced Zee-80 rather than Zed-80. Which means Sinclair’s Zed-X 80 used a Zee-80! Just to keep us Brits on our toes…
Isn’t there other fabs making other variations of the architecture?
I thought this bulletin referred to just the older node implementation?
As per the end of the video the newer eZ80 is the logical next step but it is not in the original 40 pin configuration any more and is not 100% chip compatible
No mention of the FOSS project to keep the Z80 alive?
Ahhhhh 8bits microprocessors, assembler programming’ push and pop ! I still have my « Zach’s » programming handbooks for the Z80 but also the competing 6502 (that was used in apple…) cheers
I think you mean "zed" 80 😊
Except the ZX Spectrum 16K was £125 in July 1982 and was only reduced in price to £99 in 1983.
Made a bike speedo with z80 that needed no ram , and because it was completely static the clock could be stopped to save power
A sad day indeed...
We've made so many stuff with this CPU... oh boy! Still I can speak fluently Z80-Assembler. 😂❤
Gameboy wasn't a Z80. It was an 8080 with a different set of extra instructions
No way was Z80 faster than 286. The 8088 was limited by the 8 bit bus which meant instructions took more time to fetch than to execute. Also many early software likely was written for 8080 and just cross assembled. 8086 was assembler level compatible with 8080.
I thought it was the "Zed" 80 to us here in the UK.
Tomato, Tomato 🤷🏻♂️
It’s an American made chip so the American pronunciation is correct. But the ZX Spectrum should be pronounced with a Zed as it’s British.
@@mattl_ ZEE EKS SPECTORUM
As a British English speaker (I'm from Scotland), When I wrote the script I literally had to write it phonetically to stop me saying ZED 80! However, since it's an American product, I guess they should have this one!
@@mattl_ Sorry, that's not how it works - it's a letter, not a word.
The 6502 was in more things than most people realized. Who has a original NES? By original I am referring to the ones that were out in 1989. These were one of those consoles that had a lot of people blowing on or cleaning the cartridge contacts a lot.
The NES used a bootleg copy of the 6502 made by Ricoh that had some parts of the die deactivated so they could try and claim it wasn't a direct copy. However MOS Technology was suspicious and x-rayed a sample which showed it was made from stolen masks obtained through industrial espionage. Caught red handed, Nintendo and Ricoh basically pointed their fingers at each other with Ricoh claiming Nintendo provided the masks saying they were reverse engineered and Ninteno claiming Ricoh had told them they reverse engineered the masks with each side saying that they "dindu nuffin"
Poderiam estender até 2026 e assim arredondar as décadas.
I wonder how they manufactured this chip all these years? The fab equipment must have been held together with bailing wire and duct tape? Or maybe they had inventory?
o7 Z80
Ah yes my ti 84
Well. That it’s faster than the commodore chips is not completely true on 95% of the use cases. The mos chips could execute code on both falling and rising clocks while the z80 lacking registers and had to run several clock cycles to do what the mos chips could do in half a clock cycle.
17:16 Microsoft was founded with the vision that 640K ought to be enough for anybody.
Oh no. Today is June 15th.
I forgot to order my ton of Z80 in case NASA needs to buy some from the second hand market in 20 years.
I think retrospectively it was good of intel not to sure them as they made the ISA so successful
so sad. I ordered brand new Z80 CPUs from Digikey a couple of years ago.