synthesizable AM2901 and family bit slice models?

Discussion in 'VHDL' started by Mike Kopp, Aug 7, 2006.

  1. Mike Kopp

    Mike Kopp Guest

    We are looking at redesigning a PCB with a 16-bit processor built out
    of bit slice components. The components used are the AM2901, AM2902,
    AM2911, and AM2914. We would put all of the design into an FPGA.

    I have been able to find a commercial vendor for the AM2901 (Cast,
    Inc.) but they don't have the others. I was also able to find a
    synthesizable AM2901 model (I don't remember the URL but it was on one
    of the links from the Free Model Foundry,
    http://www.freemodelfoundry.com/). This is old (predates std_logic
    and I'm not sure about copyright.

    Does anyone know of any sources for these models? A couple are
    complicated enough to be not terribly difficult but not trivial
    either.
     
    Mike Kopp, Aug 7, 2006
    #1
    1. Advertising

  2. On Mon, 07 Aug 2006 08:33:06 -0400, Mike Kopp
    <> wrote:

    >We are looking at redesigning a PCB with a 16-bit processor built out
    >of bit slice components. The components used are the AM2901, AM2902,
    >AM2911, and AM2914. We would put all of the design into an FPGA.


    Sorry, I can't help you (but that certainly doesn't mean that such
    things don't exist). However.... IIRC the 29xx family weren't
    outrageously fast by today's standards - 25MHz-ish??? - and
    though it pains me to say it, I can't help wondering whether
    it might be easier to write an emulator in pure software,
    running on a fast modern general-purpose machine.

    Or, since you're in academia and therefore presumably
    not hidebound by strange requirements to preserve
    the original machine code, it might be easier to re-write
    the software to run on a modern platform.

    I'm sure you've thought about those possibilities already,
    but it is not a good idea to underestimate the difficulty of
    making any non-trivial CPU design work 100% right,
    particularly if you're trying to preserve exact backwards
    compatibility. A software-driven solution may prove to
    be less work, and more reliable.
    --
    Jonathan Bromley, Consultant

    DOULOS - Developing Design Know-how
    VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services

    Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK

    http://www.MYCOMPANY.com

    The contents of this message may contain personal views which
    are not the views of Doulos Ltd., unless specifically stated.
     
    Jonathan Bromley, Aug 10, 2006
    #2
    1. Advertising

  3. On Thu, 10 Aug 2006 19:21:00 +0100, Jonathan Bromley <> wrote:

    > However.... IIRC the 29xx family weren't
    >outrageously fast by today's standards - 25MHz-ish??? - and
    >though it pains me to say it, I can't help wondering whether


    They were pretty fast for their time in 5 um LS-TTL and would
    gain a lot from 90 nm technology. The chip family was documented
    very well at the register transfer level and converting this to a
    VHDL netlist requires some meticulous work, but is
    no intellectual challenge.

    Some 2901s + 2902 will collapse to a single DSP48 block
    in a Virtex4, plus a few gates. The chips were MSI only
    and the IP was in the microcode ROMs. Make sure that you
    can read these.

    AMD had an excellent booklet series on the 2900 family. The
    title was something like "Build your own microprocessor, today".
    Described every little bit :)

    >but it is not a good idea to underestimate the difficulty of
    >making any non-trivial CPU design work 100% right,
    >particularly if you're trying to preserve exact backwards
    >compatibility. A software-driven solution may prove to
    >be less work, and more reliable.


    It could easily be that 29xx+microcode is better documented
    than the resulting machine. And if it's something like a
    disk or graphics controller, then there won't be anything like a
    conventional CPU, just hardware + microcode.

    Gerhard
     
    Gerhard Hoffmann, Aug 10, 2006
    #3
  4. Mike Kopp

    Guest

    Gerhard Hoffmann wrote:
    > AMD had an excellent booklet series on the 2900 family. The
    > title was something like "Build your own microprocessor, today".
    > Described every little bit :)



    I think you are referring to "Build a Microcomputer" by AMD.

    Looks like someone brave soul saved this book from extinction:
    http://buzbee.net/bitslice/

    [note: the PDF files are huge, and the site is slow]

    Also, bitsavers.org and wikipedia can point you to the complete
    datahseets





    - Bruns
     
    , Aug 12, 2006
    #4
  5. Mike Kopp

    Eric Smith Guest

    Jonathan Bromley wrote:
    > However.... IIRC the 29xx family weren't
    > outrageously fast by today's standards - 25MHz-ish??? - and


    Gerhard Hoffmann wrote:
    > They were pretty fast for their time in 5 um LS-TTL and would


    The fast ones were actually ECL internally, with built-in level
    conversion on the IO. IIRC, it was a process developed by National
    Semiconductor for their IDM2900A (and -B, -C) family, though the
    other vendors including AMD followed suit.
     
    Eric Smith, Aug 14, 2006
    #5
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. vinjvinj
    Replies:
    15
    Views:
    600
    Jeremy Sanders
    Nov 10, 2005
  2. Jean-Paul Calderone
    Replies:
    0
    Views:
    450
    Jean-Paul Calderone
    Nov 7, 2005
  3. Replies:
    3
    Views:
    1,855
    Timothy Bendfelt
    Jan 19, 2007
  4. Replies:
    9
    Views:
    1,049
    Juha Nieminen
    Aug 22, 2007
  5. David Heinemeier Hansson
    Replies:
    0
    Views:
    249
    David Heinemeier Hansson
    Dec 23, 2004
Loading...

Share This Page