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What's so special about Z80? - Page 2 — Parallax Forums

What's so special about Z80?

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  • BTW, it seems Chip Gracy started his computing career with a Timex Sinclair. I believe that was a Z80 device and a very tiny one.

    Forgive me, this post is redundant. I tried to delete, but for some reason I can't. Nonetheless, it is a bit of interesting history.



    Yes that is the one I owned, I had a memory fault in a previous post, I bought it at Sears in a new local mall, never got to much done with it, special none the less.
  • In the 80s I had a friend who was a CP/M and Z80 user and although his machine was a tad dull (a monochrome display and no sound), it was fairly capable as a platform for word processing, terminal emulation, and programming. I was a 6502 user on the Atari and their were good games, but productivity software was a little harder to come by. But both of us were able to avoid trips to RPI's computer center using dial up and VT-100 emulators.

    Another guy on our floor had a TI-99/4a which could have been an awesome machine had TI not made some bad design tradeoffs. The TMS9900 processor was 16 bit and its TMS9918a graphics chip had its own RAM and memory bus. But TI inexplicably limited main RAM to 256 bytes and had programs access the VDP RAM which made the whole thing a waste. It's no surprise that the 99/4a failed in the market.

    However the TMS9918A VDP was adopted by the Z80 based MSX computers which weren't well known in the US, but were popular abroad. The result was that some Z80 based machines had graphics and sound almost as good as the Atari.
  • kwinnkwinn Posts: 8,697
    MikeDYur wrote: »
    Hi,
    All this talk about retro computing, had me search the forum for a micro I never got to talk to, I was around seventeen when I bought the NS SC/MP Evauation Kit, I probably put it together the same day it came in the mail. It took me awhile to get a power supply together, and my original plan was to use a WWII Klienshmidt Teletype as a terminal, but instead opted to put together a popular TV Typewriter at the time. I had all the pieces put together but never got them conected each other, a new PC may have had my attention.

    My question is, do I want to go with the old school binary in/out? or interface to a Propeller for terminal emulation? Because it's an old board, I thought it should be in a cabinet on it's own, a great trainer. On the other hand a hybrid would be more fun, and finish what I started forty year's ago.

    Any ideas or inspiration would be appreciated.

    _mike

    IIRC most of the evaluation kits from that time period used a serial interface or had a 7 segment display and keypad. Not familiar with the scamp but from your post it sounds like it had the serial interface. If you still have the TV Typewriter I would suggest using that. It was an important and popular piece of hardware of that era.

    If not I would go with the propeller terminal emulation hybrid idea.
  • Heater.Heater. Posts: 21,230
    edited 2015-12-22 04:16
    Spud,
    Oh boy! Look at that ceramic package
    I'm tearful here. No, seriously.

    That little board is something of a famous landmark in computer history.

    And I just had a huge overdose 1970's chip nostalgia with Julian Ilett's run though a collection that was sent to him:

    and



  • potatoheadpotatohead Posts: 10,261
    edited 2015-12-22 04:15
    I had a couple ceramic package CPUs, and lost 'em in a move. It's my favorite package. Just looks expensive and techie. Great video Heater! Looking at those old datasheets brings back a lot of memories related to peering at them, working to figure out what it all meant.

    Was it Don Lancaster's TV Typewriter?

    Yeah, productivity software on 6502 was kind of hard to find. I think that's part of why the Apple ][ saw so much of it. That machine had 80 column display and fast disks and expansion, a lot like the S100 and CP/M machines often did.

    An Apple, with CP/M card, was actually a very capable business / 8 bit workstation. Add in some I/O, and those could do a lot! That, and it's non-game focus seemed to attract all of those kinds of users.

    Anyway, I second the suggestion to use the TV Typewriter, if it still works. Otherwise, the Propeller can probably duplicate it's video signal near perfectly, if you want a total nostalgia feel. Mount one in a keyboard, get an old TV, and you are SET!



  • That was collection of chips, indeed! What will you do with that chips?
  • Heater.Heater. Posts: 21,230
    Spud.

    Some of them were expensive. Until a few years a go I had a couple of new unused 8751's. Ceramic package, gold lid/EPROM window. Some 300 GBP each when they were purchased.

  • potatoheadpotatohead Posts: 10,261
    edited 2015-12-22 04:35
    Did you see some of the MIL spec CPU's in that collection? Grey ceramic with gold, soldered caps and shield connect. $$$ back then for sure.

    The Internet is awesome. I would totally send that guy a box of chips, just to get the rundown, and share in his curious joy over so many odd, and old devices.

    Some of those packages are crazy! There were a few I've not seen before.
  • Heater.Heater. Posts: 21,230
    Oh yeah. I spent the first few years of my working life in an R&D lab of the Marconi Radar company. The place was awash with such devices. Ahh...sigh...

    Somewhere I still have a big cardboard box full of 1970/80 vintage TTL. None so beautiful as Julian's collection there.

    This is why I'm stuck on DIP Props :)

    Oh, here we go: Marconi Radar : http://www.radartutorial.eu/19.kartei/karte112.en.html

    B48104.jpg

  • kwinn wrote: »

    IIRC most of the evaluation kits from that time period used a serial interface or had a 7 segment display and keypad. Not familiar with the scamp but from your post it sounds like it had the serial interface. If you still have the TV Typewriter I would suggest using that. It was an important and popular piece of hardware of that era.

    If not I would go with the propeller terminal emulation hybrid idea.





    Sadly the SC/MP was the only thing to survive that era in my life,


    @Potatohead, Don Lancaster designed the tv typewriter kit I had, there were a couple of add on board's, the serial interface was one of them, I think there was extra memory I didn't have.

    @Heater, I can't wait to see these videos when I have better reception.


    _mike
    801 x 621 - 101K
  • kwinnkwinn Posts: 8,697
    MikeDYur wrote: »
    kwinn wrote: »

    IIRC most of the evaluation kits from that time period used a serial interface or had a 7 segment display and keypad. Not familiar with the scamp but from your post it sounds like it had the serial interface. If you still have the TV Typewriter I would suggest using that. It was an important and popular piece of hardware of that era.

    If not I would go with the propeller terminal emulation hybrid idea.





    Sadly the SC/MP was the only thing to survive that era in my life,


    @Potatohead, Don Lancaster designed the tv typewriter kit I had, there were a couple of add on board's, the serial interface was one of them, I think there was extra memory I didn't have.

    @Heater, I can't wait to see these videos when I have better reception.


    _mike

    Too bad the TV Typewriter is gone, but you can always use a propeller chip and an old PS2 keyboard to build an equivalent terminal. You could also use a PC and USB-Serial adapter to test the scamp board.
  • kwinn wrote: »

    Too bad the TV Typewriter is gone, but you can always use a propeller chip and an old PS2 keyboard to build an equivalent terminal. You could also use a PC and USB-Serial adapter to test the scamp board.




    Thanks those are great directions to head, as soon as I can find my computer power supply tester, I think this board might be a candidate, it's designed for automotive use.

    640 x 480 - 162K
  • kwinnkwinn Posts: 8,697
    MikeDYur wrote: »
    kwinn wrote: »

    Too bad the TV Typewriter is gone, but you can always use a propeller chip and an old PS2 keyboard to build an equivalent terminal. You could also use a PC and USB-Serial adapter to test the scamp board.




    Thanks those are great directions to head, as soon as I can find my computer power supply tester, I think this board might be a candidate, it's designed for automotive use.

    Happy to help and curious to see where this leads. Not sure how much current the scamp board draws but I suspect one of the heftier (1.5-2A) wall warts would probably work if the one you have is nfg. You know using the propeller for the terminal would also let you interface a mouse to the scamp as well. May not be very useful, but you could at least have it send cursor(x,y) style commands to the scamp, and it would probably be a first for that micro.
  • From what I remember, it requires four or five different voltages, +5V, -5V, +12V,-12V and some other voltage. It will have to wait till I can get an electronic order out after the hollidays,>:( it's a shame I didn't save the seventy two pin socket.
  • kwinnkwinn Posts: 8,697
    You're right, now that you've jogged my memory the CPM systems needed all those voltages and 24V for the 8" floppies.
  • Heater.Heater. Posts: 21,230
    Wow, even I have never seen a CP/M system with 8 inch floppies!

    Last used 8 inch floppies on the original Intel dev systems for 8080/8085.
  • https://en.m.wikipedia.org/wiki/TV_Typewriter#/editor/3

    This was inexpensive and pretty cool.
  • Well that didn't work.

  • kwinnkwinn Posts: 8,697
    Heater. wrote: »
    Wow, even I have never seen a CP/M system with 8 inch floppies!

    Last used 8 inch floppies on the original Intel dev systems for 8080/8085.

    A surprising number of 64K Z80 systems with dual 8 inch floppies and CPM were sold to lawyers, accountants and doctors. Couldn't afford the 8 inchers myself, they were $985.00 each at that time, but they held a whopping 480KB. Poor me, I had to settle for 5.25 incher's that only stored 88KB.
  • kwinnkwinn Posts: 8,697
    edited 2015-12-22 19:17
    MikeDYur wrote: »
    https://en.m.wikipedia.org/wiki/TV_Typewriter#/editor/3

    This was inexpensive and pretty cool.

    While it would have been nice to have something of similar vintage to the scamp board any one of the propeller boards could be used to provide way more functionality than those boards provided.

    Any idea of how much memory the scamp could address and how much is on the board?

    PS try this link: https://en.m.wikipedia.org/wiki/TV_Typewriter
  • I got to use an 8 inch system as a kid. The form factor was perfect for desk side use.
    https://en.m.wikipedia.org/wiki/CADO_Systems

    They gave it to us in return for moving their office. Cool old computer. Ours was a two disk, multi user system. One disk for virtual storage and general data storage, the other for the running application.

  • kwinnkwinn Posts: 8,697
    potatohead wrote: »
    I got to use an 8 inch system as a kid. The form factor was perfect for desk side use.
    https://en.m.wikipedia.org/wiki/CADO_Systems

    They gave it to us in return for moving their office. Cool old computer. Ours was a two disk, multi user system. One disk for virtual storage and general data storage, the other for the running application.

    The CPM systems were similar, although generally not multi user. Floppy "A" for booting and programs, Floppy "B" for data storage.
  • Heater.Heater. Posts: 21,230
    One of my fondest memories is the time I found that rebuilding all our code base was taking far too long.

    I split the job up over three Intel MDS systems, each with three 8 inch floppy drives.

    This was cool. One drive for OS, compiler and tools. One drive for our source code. One drive for the compiled output.

    They were all in the same room. When I set them running it was a glorious symphony. Whirr, clunk, whirr clunk, whirr clunk. Each machine cycling around all it's drives.

    At the end of the day the job was done!



  • kwinn wrote: »
    You're right, now that you've jogged my memory the CPM systems needed all those voltages and 24V for the 8" floppies.

    It's not as bad as I thought, +5V and -12V is all it takes, I don't know what I was thinking of, that's simple enough, when the -12V regulator is on board.
  • Heater. wrote: »
    ...8751's. Ceramic package, gold lid/EPROM window. Some 300 GBP each when they were purchased.

    Sigh. My first microcontroller.
  • Heater. wrote: »
    Last used 8 inch floppies on the original Intel dev systems for 8080/8085.

    MDS Series II?

    Sigh. My first development system.

  • Heater.Heater. Posts: 21,230
    Yep. Like this:

    intel_intellec_mds_series_2_klein.jpg

    We put the two extra floppies above the screen though.

    Not quite my first dev system though. We had to build that ourselves, PROM programmer, VT100 terminal, wire wrapped proto board, home made cassette tape storage.


  • Heater. wrote: »

    MikeDYur,

    Not sure what you mean. If you have an SC/MP that can talk to a teletype why not just use a Prop as a VT100 terminal and talk to that instead?







    Is there a link to a current version of VT100 emulator for the prop?
  • First S100 system I soldered together in the 80's run CPM and had dual 8" floppies. The cpu was a Jade Big Z with 64k of ram. Most of the parts like drives, power cam from hamfests of the time. We even made a eprom burner for it. Televideo terminal from my buddy surplus electronics store. Great time figuring out CPM commands.
  • kwinnkwinn Posts: 8,697
    MikeDYur wrote: »
    Heater. wrote: »

    MikeDYur,

    Not sure what you mean. If you have an SC/MP that can talk to a teletype why not just use a Prop as a VT100 terminal and talk to that instead?







    Is there a link to a current version of VT100 emulator for the prop?

    There is the Pocketerm kit at http://www.brielcomputers.com/wordpress/?cat=25 for $69.00.

    You could also use one of the VGA display objects as the starting point of your own project. Between the VGA and serial objects the hard part is done as far as creating a "glass teletype" goes.
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