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Z80 – The 1970s Microprocessor Still Alive (2021)
- t1234s 1mo agoI just sold my Z80 motherboard on ebay.
- asdefghyk 1mo agoA paragrap from the linked articale Z80 was the choice of a microprocessor for then home computers such as Radio Shack TRS-80, SORD M23P, M5, Sinclair ZX81, ZX Spectrum, KayPro II, and many other manufacturers.3 It was capable of running the CP/M operating system in most Z80-based PCs. Z80 had a reasonable share in the PC market until Intel revealed its 16-bit microprocessor in the mid-1980s. Z80 was very popular as a microprocessor not only in PC applications, but also in industrial embedded applications, and some of the big manufacturers have Z80 core inside their ASIC chips still today or use enhanced versions of Z80 in consumer electronic devices.4–7 Zilog still manufactures ez80, an enhanced version of the original Z80, which is still being used by Texas Instruments in its TI-84 and TI-84 Plus calculators.7 It is among the few silicon chips that made a remarkable impact on the electronic device industry.8 To this day, Zilog produces a range of Z80-based microprocessors and intelligent peripheral controllers, and they are available from reputed electronics component suppliers.2,9,10 This microprocessor is one of the longest living microprocessors of all time.
- smackeyacky 1mo agoSlop from the article
- aruggirello 1mo agoZ80 also powered the whole MSX line of home computers, how could have he missed that?!?
- Gormo 1mo agoAlso mentioned the KayPro II but omitted the Osborne 1.
- meekins 1mo agoDue to its simplicity it's a fun little processor to program. Hacking on some assembly on a ZX spectrum emulator is a nice way to stay sane in this high abstraction LLM age.
- flohofwoe 1mo ago"Simple" is really not a word I would associate with the Z80 ;) The ISA is quite messy because of the backward compatibility requirement with the Intel 8080 (e.g. the Z80 had to fill undocumented gaps in the 8080 opcode encoding map with new instructions, four of which were prefix instructions to unlock additional instruction 'subsets' (DD/FD for replacing instructions involving the HL register pair with indexed addressing modes via the IX/IY registers, and ED/CB prefixes for adding two entirely new opcode blocks). If the Zilog engineers would have been free to design their own ISA I'm sure they would have been able to come up with a much more elegant design. Also the Z80 had more than twice as many transistors as the 6502 (8500 for the Z80 vs 3500 for 6502). I still prefer programming the Z80 over the 6502 though :)
- dosisking 1mo ago> If the Zilog engineers would have been free to design their own ISA I'm sure they would have been able to come up with a much more elegant design. Since Zilog was founded by former Intel engineers, they were probably the ones who helped design the 8080 in the first place?
- rvba 1mo agoI am simplifying a lot since there were much more chips involved... but 3500 transistors to have countless hours of fun to play NES games really puts things into perspective My 5090 has 92 billion transistors (I dont say they dont bring fun)
- Lio 1mo ago> If the Zilog engineers would have been free to design their own ISA I'm sure they would have been able to come up with a much more elegant design. That's an interesting idea. They were previously part of the team that designed the 8080 so they must have been very familiar with the ISA and the design philosophy. I'm sure they'd be able to come up with improvements but how much more elegant it would have been is hard to say.
- julienmartlet 1mo agoIronically (and sadly) the Z80 was discontinued not very long after this piece was published.
- grishka 1mo agoI'm sure clones are still being made.
- nubinetwork 1mo agoThe cpu possibly, but I had a hard time trying to find the support chips (ctc, sio/pio, etc)...
- avadodin 1mo agoMany applications didn't even use those peripherals so I suppose production ended earlier. The Z80 could even refresh the RAM by itself. It was not like the 8080 which required two support chips only to function.
- HeyLaughingBoy 1mo agoDo you have an actual use for them? I might have a few tubes of Z80-CTC & SIO in the basement if I haven't given them all away yet.
- JoeAltmaier 1mo agoIt's still active as a mask for a more complex system on a single die. Even the support chips are available. The Juno project, orbiting Jupiter, had a Z80 compatible core for the radar signal processing.
- dragontamer 1mo agoWe still have the venerable 8051 for anyone who likes old architectures!!
- spicyjpeg 1mo ago
- getfacl 1mo agoTom Jennings, the creator of fidenet, is producing a nice modern Z80 computer[0] 0. https://www.ebay.ie/itm/206496219323 https://www.ebay.ie/itm/206496219323
- varjag 1mo ago(emulated)
- pinewurst 1mo ago(on a 600 Mhz Teensy 4.1)
- JKCalhoun 1mo agoRC2014 is the real deal: https://rc2014.co.uk https://rc2014.co.uk Why I have not picked one up yet… I think I just have a sweet spot for the 6502 and keep putting together KIM-1 kits. (EDIT: Finally after years, I just pulled the trigger on their Classic II kit.)
- Gormo 1mo agoI don't know -- I'm seeing a lot of corner-cutting in the board designs!
- mysterydip 1mo agoI think they’re a notch above the rest
- roygbiv2 1mo agoIt's actually fairly easy and interesting to design your own z80 computer. I went from knowing about assembly and pcb design to a z80 computer with a serial interface and memory banking. Learnt a lot on the way an went on to build pcbs for other projects with the knowledge I had gained from that.
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- librasteve 1mo agointeresting to be reminded that an 8080 (8 bit datapath) took 4,800 transistors an Apple M5 Max is 100,000,000,000 transistors (ok it’s 18 CPU + 40 GPU cores) by comparison so 17 million 8080 equivalents
- TacticalCoder 1mo agoYup and Moore's law about transistors doubling every 18 to 24 months did basically hold, which is even more impressive. Foreseen it was.
- flohofwoe 1mo agoNitpicking, but since the M5 includes cache and GPU a more realistic comparision would probably be to count all transistors in an entire 8-bit home computer system against a modern integrated GCPU (e.g. from googling around a C64 might have around 0.75 million transistors, most in the memory chips). And in a way, those old 8-bit home computers also worked like a single integrated 'super-chip', because the whole system was driven by a single clock and entirely 'hard realtime', while modern computers are much more asynchronous (and I guess this asynchronous design is what enabled most performance improvements that go beyond pure transistor count scaling).
- dosisking 1mo agoThis is understandable, considering that the M5 is the Ultimate Computer, powered by Dr. Richard Daystrom's very own engrams
- librasteve 1mo agoexcellent point
- ThrowawayR2 1mo agoBut the M5 is clearly not safe to use in Enterprise¹ computing environments. ¹ USS Enterprise, that is.
- dofm 1mo agoThe ARM 1 only had 25,000 or so.
- zeninkhan 1mo ago[flagged]
- Lio 1mo ago> Then, as a young engineer, I worked in a large mainframe computer system based on Z80. This sentence threw me a little bit. Which mainframes were based on the Z80? I'd love to know more about that.
- helf 1mo agoIf it wasnt some mostly custom system it was probably an HP 64000 Logic Development System. Which used Z80s to run user facing software and control the actual mainframe. I doubt it was a pure Z80 "mainframe". Loved to be proved wrong though!
- buescher 1mo agoS100 systems were sometimes called mainframes after their card cage construction: usually with the qualifier “s-100 mainframe” for the system or the enclosure and backplane.
- JPLeRouzic 1mo agoMorrow systems ran on a Unix flavor, could address 16MB all on Z80, had memory protection and could have up to 6 simultaneous users. Micronix was the only Unix-like multiuser system ever to run on an 8 bit processor. https://ia902902.us.archive.org/20/items/mame0.211manualsfullset/mpz80.pdf https://ia902902.us.archive.org/20/items/mame0.211manualsful...
- nineteen999 1mo agoUntil Fuzix of course.
- AIorNot 1mo agoThe inventor of the Z80 Fredrico Faggin is promoting a consciousness first universe now https://youtu.be/-vz5LU2ECm0?is=g1T-QM8Lq9qNyiNK https://youtu.be/-vz5LU2ECm0?is=g1T-QM8Lq9qNyiNK
- kayamon 1mo agoI read his book, honestly I think he's right.
- JoeAltmaier 1mo agoMy first ambitious project was a Z80 assembler. The Z8000 (much later) was distinguished by being the last random-logic (not microcoded) microprocessor of it's day.
- evalystai 1mo agoReminded me good old days.. games loaded from cassette recorder and my first program for Spectrum which was a simple drawing tool I proudly called "graphic editor" :)
- christkv 1mo agoInteresting interview with Frederico Faggin on of the two designers of the z80 https://m.youtube.com/watch?v=28JtL1WVjMw https://m.youtube.com/watch?v=28JtL1WVjMw
- RomanPushkin 1mo agoRare find https://www.zosya.net/file/TTT_in_detail.pdf https://www.zosya.net/file/TTT_in_detail.pdf - Russian, probably can be translated easily, long story on how one of the games for ZX was made
- analog31 1mo agoThe Z80 was my "first" microprocessor, in an odd way. I've never touched one. It was the early 80s, and my mom was getting Byte Magazine, which I devoured. I had taken a high school programming class in BASIC, and was interested in electronics. Radio Shack had a shelf of books, and I was going through them one by one as I could afford them. They had William Barden's book on the Z80, published by Howard Sams, because the TRS-80 used it. That book was so clearly and methodically written, that a high school kid could understand it. Later on I added some scraps of inline assembler here and there in programs, but eventually got into microcontrollers, which I continue to play with. I admit that my mental model of microcontrollers is still based on those 8 bit machines, and I owe a debt to the Z80.
- avadodin 1mo agoI only went through the partially rat–soiled magazines my dad "stored" in his in-laws root cellar many decades later but I still love the CPU.
- Sulfide6416 1mo agoThe Z80 living on as the eZ80 in embedded gear says a lot - a well-designed 8-bit core can outlast entire architectures built to replace it.
- userbinator 1mo agoAnyone who had a cheap media player in the early 2000s probably had one with a Z80-based SoC: https://en.wikipedia.org/wiki/S1_MP3_player https://en.wikipedia.org/wiki/S1_MP3_player
- forest_brothers 1mo ago[flagged]