Home built Z80 computers - CP/M

This is a discussion on Home built Z80 computers - CP/M ; Allisonnospam@nouce.bellatlantic.net wrote: > On Mon, 22 May 2006 00:25:26 -0500, dowcom@webtv.net (bud) wrote: >> >>Vis-a-vis bussing: >> >>Why not take a page from the PC104 scheme? > cost and complexity. Except for the difficulty of getting long-tailed DIN connectors, it ...

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Thread: Home built Z80 computers

  1. Re: Home built Z80 computers

    Allisonnospam@nouce.bellatlantic.net wrote:
    > On Mon, 22 May 2006 00:25:26 -0500, dowcom@webtv.net (bud) wrote:


    >>
    >>Vis-a-vis bussing:
    >>
    >>Why not take a page from the PC104 scheme?


    > cost and complexity.


    Except for the difficulty of getting long-tailed DIN connectors, it
    works fine for the P112.


    --
    David Griffith
    dgriffi@cs.csbuak.edu <-- Switch the 'b' and 'u'

  2. Re: Home built Z80 computers


    Tarkin wrote:
    > Allison, why do your messages self-destruct? It's
    > like Mission Impossible or something..
    >

    Look at the headers on the message - see "X-No-Archive: yes"?


  3. Re: Home built Z80 computers

    On 23 May 2006 00:43:21 -0700, "anoneds@netscape.net"
    wrote:

    >
    >Tarkin wrote:
    >> Allison, why do your messages self-destruct? It's
    >> like Mission Impossible or something..
    >>

    >Look at the headers on the message - see "X-No-Archive: yes"?


    Prevents backward farming for email addresses. Doesn't hurt that
    the address is limited only to usenet postings (dead letter box).
    I've had too many spams that the origin was a result of usenet
    postings. This approach seems to help.

    Allison

  4. Re: Home built Z80 computers

    "anoneds@netscape.net" wrote:
    > Tarkin wrote:
    >
    >> Allison, why do your messages self-destruct? It's
    >> like Mission Impossible or something..

    >
    > Look at the headers on the message - see "X-No-Archive: yes"?


    I wish that header was automatically shown on my newsreader. On
    principle I will not give help to anyone that is so anti-social as
    to use it.

    --
    "If you want to post a followup via groups.google.com, don't use
    the broken "Reply" link at the bottom of the article. Click on
    "show options" at the top of the article, then click on the
    "Reply" at the bottom of the article headers." - Keith Thompson
    More details at:
    Also see


  5. Re: Home built Z80 computers

    CBFalconer schrieb:

    >> Look at the headers on the message - see "X-No-Archive: yes"?

    >
    > I wish that header was automatically shown on my newsreader. On
    > principle I will not give help to anyone that is so anti-social as
    > to use it.


    Look at the more modern successor of your client: SeaMonkey.

    There is a very powerful and valuable extension, named Mnenhy, that
    allows customization of the header display - including showing the XNA
    header (in red here).

    --
    Dipl.-Ing. Tilmann Reh
    http://www.autometer.de - Elektronik nach Maß.

  6. Re: Home built Z80 computers

    >....Those are part number Z84C50.....
    JDR are good folks. That price isn't bad, either,
    for what you get. I like it.

    >Prevents backward farming for email addresses.

    Oh! I just thought it was unusual (Although, since I
    access from Google Groups[1], it makes it easy
    to zip right to your posts)

    >...32k of rom setup for 0000h on boot and port to

    enable/disable.....

    >Logic (minimal) to implement mode 2 interrupts without
    >Z80 peripherals. (a few peices of ttl usualy does this well.).


    I'm rusty on my mode 2 ints; and why no z80 peripherals?
    Did you mean designing the logic w/o the EIEIO?
    When I designed my breadboard controller, I included
    the circuitry to filter out the intr ACK, beceause I had
    planned to use the design in other projects where I
    would be using intr's.

    It all sounds pretty spot on to me. Looks like
    for the most part we're still firm on the z80
    for cpu. I like the idea for keeping the
    base design to 8-bit all 'round- it's 16 less
    lines.

    Would you give me some more insight into
    your mode 2 intr schema? And have you
    had any thoughts on the physical bus?

    [2]- No guff on this one,please. It works
    for me.

    TTFN,
    Tarkin


  7. Re: Home built Z80 computers

    On 24 May 2006 05:18:23 -0700, "Tarkin" wrote:

    >
    >>...32k of rom setup for 0000h on boot and port to

    >enable/disable.....
    >
    >>Logic (minimal) to implement mode 2 interrupts without
    >>Z80 peripherals. (a few peices of ttl usualy does this well.).

    >
    >I'm rusty on my mode 2 ints; and why no z80 peripherals?


    Mode 2 is the device supplys vector. Vector is the low 8bits (bit
    0=0) and the IR supplies the high 8bit address. Handy for CP/M
    as it makes it easy to put interrupt vectors in high mem rather than
    low as in 8080 (without 8259).

    Z80 perpiherals are not that common compared to z80s
    and much more costly. Some like the Z80 DMA were never built for
    faster than 4mhz operation.

    >Did you mean designing the logic w/o the EIEIO?


    ????? Without the IO?

    I'll assume. For a minimum system it would be two boards.

    Board 1 would be CPU and MEMory system. Memory being ram and rom.
    Board 2 would have the IO plus interrupt.

    The bus needed between them is smaller (only 8 bit data, 8bit address
    plus controls).

    >When I designed my breadboard controller, I included
    >the circuitry to filter out the intr ACK, beceause I had
    >planned to use the design in other projects where I
    >would be using intr's.


    optional.

    >It all sounds pretty spot on to me. Looks like
    >for the most part we're still firm on the z80
    >for cpu. I like the idea for keeping the
    >base design to 8-bit all 'round- it's 16 less
    >lines.
    >
    >Would you give me some more insight into
    >your mode 2 intr schema? And have you
    >had any thoughts on the physical bus?


    The logic to do this is a trivial combination of IORQ/ and M1/
    (signifies an interrupt response) and a 8bit tristate device
    (or gates) like a LS244 to gate a 7bit value to the data bus
    with bit 0=0. The value can be an encoded number from
    a 74148 (or other rom) or simple asserting a line. The result
    is IR has the high 8bits and the gated data from this IR port
    has the low 8bits of an address vector.

    The 74ls148 is a 8line to 3line encoder. Since I have
    74ls148s I use them. Two of them give 15 encoded
    vectors (low byte n= 000v vvv0) for a cost of 3 1/4 ttl
    packages. You can also do a simple linear select for
    7 addresses by leaving out the '148s where n=vvvv vvv0.

    Another way to use mode2 is to force the databus to zero
    or all 1s during IORQ/ and M1/ for a single address interrupt
    in the range of where IR points to.

    Allison






  8. Re: Home built Z80 computers

    Tilmann Reh wrote:
    > CBFalconer schrieb:
    >
    >>> Look at the headers on the message - see "X-No-Archive: yes"?

    >>
    >> I wish that header was automatically shown on my newsreader. On
    >> principle I will not give help to anyone that is so anti-social
    >> as to use it.

    >
    > Look at the more modern successor of your client: SeaMonkey.
    >
    > There is a very powerful and valuable extension, named Mnenhy,
    > that allows customization of the header display - including
    > showing the XNA header (in red here).


    I have tried Thunderbird, and found enough petty annoyances and
    missing abilities (compared to Netscape 4.75) that I abandoned it.
    Maybe 2.0 will be better for me.

    --
    "If you want to post a followup via groups.google.com, don't use
    the broken "Reply" link at the bottom of the article. Click on
    "show options" at the top of the article, then click on the
    "Reply" at the bottom of the article headers." - Keith Thompson
    More details at:
    Also see



  9. Re: Home built Z80 computers

    CBFalconer wrote:
    >
    > Tilmann Reh wrote:
    > > CBFalconer schrieb:
    > >
    > >>> Look at the headers on the message - see "X-No-Archive: yes"?
    > >>
    > >> I wish that header was automatically shown on my newsreader. On
    > >> principle I will not give help to anyone that is so anti-social
    > >> as to use it.

    > >
    > > Look at the more modern successor of your client: SeaMonkey.
    > >
    > > There is a very powerful and valuable extension, named Mnenhy,
    > > that allows customization of the header display - including
    > > showing the XNA header (in red here).

    >
    > I have tried Thunderbird, and found enough petty annoyances and
    > missing abilities (compared to Netscape 4.75) that I abandoned it.
    > Maybe 2.0 will be better for me.
    >

    I presume that you mean a newsreader named Thunderbird, and *not*
    the Thunderbird that comes in a bottle. ;-) Some posters on
    Usenet may *drive* you to seek out the bottled one.


    --
    +----------------------------------------------------------------+
    | Charles and Francis Richmond richmond at plano dot net |
    +----------------------------------------------------------------+

  10. Re: Home built Z80 computers

    Sorry, Allison, I was tired when I wrote that post.
    Lemme see if I can be a little more intelligible :

    >>Did you mean designing the logic w/o the EIEIO?

    >????? Without the IO?

    No! I meant the Interrupt Enable: Input & Output,
    that is, the hardware daisy chain. Since I often
    pursue this hobby well into the wee hours, some
    of the terms/sognals/etc become a word or
    acronym salad!

    >>When I designed my breadboard controller, I
    >>included the circuitry to filter out the intr ACK,


    >The logic to do this is a trivial combination of IORQ/
    >and M1/ (signifies an interrupt response)

    That's what I meant- I think in the Z80 documentation,
    they refer to those together as INTACK, because they
    never occur synchrously otherwise. All I did was take this
    into account when I designed the rest of my glue logic,
    and made sure that I accepted /IORQ iff !(/M1), and
    I accepted /M1 iff !(/IORQ).

    >The 74ls148 is a 8line to 3line encoder. ....

    Latches, encoders, and decoders are the cats meow!
    Designing the glue logic was one of the satisfying and
    simultaeneously challenging parts of my little project.
    As I am only an hobbyist, the logic doesn't come to
    me like (it would to) a seasoned enigneer or tech.

    I like the interrupt ideas! They should make it trivial
    to implement and extend the boards functionality.

    I found an open-source java schematic capture
    program here:
    http://www.staticfreesoft.com/

    pros: cross-platform, relatively
    flat learning curve.
    cons: No predifined IC packages;
    no way to create or import them.

    Today's poll (for all):
    Would you be in favor of, or opposed to,
    or have a better idea for, the use of a
    yahoo! group to start collation of the
    project details?

    I thought of a dumb acronym:
    ALPACA:
    Another
    Loony
    Project
    Assembled (by)
    Comitte
    Approval

    ;^)
    Cheerios,
    Tarkin


  11. Re: Home built Z80 computers

    On 24 May 2006 19:03:46 -0700, "Tarkin" wrote:

    >Sorry, Allison, I was tired when I wrote that post.
    >Lemme see if I can be a little more intelligible :
    >
    >>>Did you mean designing the logic w/o the EIEIO?

    >>????? Without the IO?

    >No! I meant the Interrupt Enable: Input & Output,
    >that is, the hardware daisy chain. Since I often
    >pursue this hobby well into the wee hours, some
    >of the terms/sognals/etc become a word or
    >acronym salad!


    Oh!

    >
    >>>When I designed my breadboard controller, I
    >>>included the circuitry to filter out the intr ACK,

    >
    >>The logic to do this is a trivial combination of IORQ/
    >>and M1/ (signifies an interrupt response)

    >That's what I meant- I think in the Z80 documentation,
    >they refer to those together as INTACK, because they
    >never occur synchrously otherwise. All I did was take this
    >into account when I designed the rest of my glue logic,
    >and made sure that I accepted /IORQ iff !(/M1), and
    >I accepted /M1 iff !(/IORQ).


    OK, I use different shorthand you you understand it.


    >>The 74ls148 is a 8line to 3line encoder. ....

    >Latches, encoders, and decoders are the cats meow!
    >Designing the glue logic was one of the satisfying and
    >simultaeneously challenging parts of my little project.
    >As I am only an hobbyist, the logic doesn't come to
    >me like (it would to) a seasoned enigneer or tech.
    >
    >I like the interrupt ideas! They should make it trivial
    >to implement and extend the boards functionality.
    >
    >I found an open-source java schematic capture
    >program here:
    >http://www.staticfreesoft.com/
    >
    >pros: cross-platform, relatively
    > flat learning curve.
    >cons: No predifined IC packages;
    > no way to create or import them.


    ICK foo poo, hate java.

    I use the old dos CADD6, SCHEMA and Microcad.
    Though a pen and lab notebook is still a favorite.

    >Today's poll (for all):
    > Would you be in favor of, or opposed to,
    >or have a better idea for, the use of a
    >yahoo! group to start collation of the
    >project details?
    >
    >I thought of a dumb acronym:
    >ALPACA:
    >Another
    >Loony
    >Project
    >Assembled (by)
    >Comitte
    >Approval


    I can go for that!!

    >
    >;^)
    >Cheerios,
    > Tarkin



  12. [OT] Modern newsclients (was: Re: Home built Z80 computers)

    CBFalconer schrieb:

    >> Look at the more modern successor of your client: SeaMonkey.
    >>
    >> There is a very powerful and valuable extension, named Mnenhy,
    >> that allows customization of the header display - including
    >> showing the XNA header (in red here).

    >
    > I have tried Thunderbird, and found enough petty annoyances and
    > missing abilities (compared to Netscape 4.75) that I abandoned it.
    > Maybe 2.0 will be better for me.


    IMHO SeaMonkey has a more full-featured and comfortable UI than
    Thunderbird. You should have a look at it - it's the successor of the
    Mozilla Suite, which is the successor of Netscape 4.7x. When I switched
    from NS 4.78 to Mozilla Suite, I didn't miss anything but enjoyed many
    new features.

    --
    Dipl.-Ing. Tilmann Reh
    http://www.autometer.de - Elektronik nach Maß.

  13. Re: [OT] Modern newsclients (was: Re: Home built Z80 computers)

    On Thu, 25 May 2006 14:20:33 +0200, Tilmann Reh
    wrote:

    >CBFalconer schrieb:
    >
    >>> Look at the more modern successor of your client: SeaMonkey.
    >>>
    >>> There is a very powerful and valuable extension, named Mnenhy,
    >>> that allows customization of the header display - including
    >>> showing the XNA header (in red here).

    >>
    >> I have tried Thunderbird, and found enough petty annoyances and
    >> missing abilities (compared to Netscape 4.75) that I abandoned it.
    >> Maybe 2.0 will be better for me.

    >
    >IMHO SeaMonkey has a more full-featured and comfortable UI than
    >Thunderbird. You should have a look at it - it's the successor of the
    >Mozilla Suite, which is the successor of Netscape 4.7x. When I switched
    >from NS 4.78 to Mozilla Suite, I didn't miss anything but enjoyed many
    >new features.


    I use none of the above. The reader here is Forte' Free Agent
    purchased version that has all the bells and whistles turned on.
    Even the free version has more features than the ones listed.


    Allison

  14. Re: Home built Z80 computers


    > On Thu, 25 May 2006 14:20:33 +0200, Tilmann Reh
    > wrote:
    >
    > >CBFalconer schrieb:
    > >
    > >>> Look at the more modern successor of your client: SeaMonkey.
    > >>>
    > >>> There is a very powerful and valuable extension, named Mnenhy,
    > >>> that allows customization of the header display - including
    > >>> showing the XNA header (in red here).
    > >>
    > >> I have tried Thunderbird, and found enough petty annoyances and
    > >> missing abilities (compared to Netscape 4.75) that I abandoned it.
    > >> Maybe 2.0 will be better for me.

    > >
    > >IMHO SeaMonkey has a more full-featured and comfortable UI than
    > >Thunderbird. You should have a look at it - it's the successor of the
    > >Mozilla Suite, which is the successor of Netscape 4.7x. When I
    > >switched
    > >from NS 4.78 to Mozilla Suite, I didn't miss anything but enjoyed
    > >many
    > >new features.

    >
    > I use none of the above. The reader here is Forte' Free Agent
    > purchased version that has all the bells and whistles turned on.
    > Even the free version has more features than the ones listed.
    >
    >
    > Allison


    Is it just me or are there hardly any sources out there for decent sized
    proto boards for us experimenters?? I don't want wire wrap, just a nice
    sized (6x10 or so) proto board with a gnd and vcc bus traces, plus
    multiple pads for each IC socket connection. It doesn't have to be S-
    100 bus or STD bus - just a basic board.

    If you have a stash or a source, I'd appreciate a pointer. Or perhaps
    we could have a good quantity run made with price break just for the
    folks here? What are your thoughts on the type of board it should be?

    tnx, john

    --


  15. Re: Home built Z80 computers

    On Sun, 04 Jun 2006 22:58:24 +0000, jaevans
    wrote:

    >Is it just me or are there hardly any sources out there for decent sized
    >proto boards for us experimenters?? I don't want wire wrap, just a nice
    >sized (6x10 or so) proto board with a gnd and vcc bus traces, plus
    >multiple pads for each IC socket connection. It doesn't have to be S-
    >100 bus or STD bus - just a basic board.


    Myself I use plated hole boards on .1" centers. Ground and power
    busses are #14 bus wire as needed. I can cut these to any size as a
    convenience as well.

    >If you have a stash or a source, I'd appreciate a pointer. Or perhaps
    >we could have a good quantity run made with price break just for the
    >folks here? What are your thoughts on the type of board it should be?


    I have a stash some 20 years old as I bought when I found them.
    But thats not to say they are not available only I haven't needed to
    look.

    Allison




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