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Re: First COSMAC ELF Supercomputer?

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  • eight_bit_jdrose
    ... Wow! The more I learn about the 1802 the more I like it.
    Message 1 of 19 , Mar 31, 2012
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      --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:
      >
      >
      > The 1802 is somewhat unique in that all bus cycles are the same length
      > (8 clock cycles), and it only does its reads/writes during *one* of
      > these cycles (TPB).
      >
      > This means you can have eight 1802's connected to a single memory. The
      > 1802's clocks operate 1 cycle out of phase, so their TPB's occur in
      > different clock cycles.
      >

      Wow!

      The more I learn about the 1802 the more I like it.
    • awasson2001
      I think this would be a great use for those 1804 chips that were selling on Ebay last year fr about a buck a piece. I ve got a couple of dozen that could be
      Message 2 of 19 , Apr 10, 2012
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        I think this would be a great use for those 1804 chips that were selling on Ebay last year fr about a buck a piece. I've got a couple of dozen that could be used in a Cosmac parallel super computer.

        Andrew

        --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:
        >
        > On 3/29/2012 11:04 AM, penguin.robot wrote:
        > > Art,
        > > Now let's just think about doing this. :)
        > > Any recommendations for interface, to connect the 1802s?
        > > We will need a parallel connection
        > > and then a way to load a program into all 1802s.
        > > I didn't check lately, but what is the availability
        > > for 1802 chips and cost?
        > > Maybe we'd end up with the first COSMAC ELF Supercomputer!
        >
        > We actually discussed this a few months ago. :-)
        >
        > The 1802 is somewhat unique in that all bus cycles are the same length
        > (8 clock cycles), and it only does its reads/writes during *one* of
        > these cycles (TPB).
        >
        > This means you can have eight 1802's connected to a single memory. The
        > 1802's clocks operate 1 cycle out of phase, so their TPB's occur in
        > different clock cycles.
        >
        > The memory is then built so it can do a read/write in a single clock
        > cycle. This isn't at all fast; at the maximum clock speed of the 1802 at
        > 5v (3.2 MHz), it only needs a 300nsec access time. It lets each 1802
        > access it during that 1802's TPB pulse. Thus all 1802's share the same
        > 64k memory space, and all of them can run at full speed.
        >
        > --
        > If you would not be forgotten
        > When your body's dead and rotten
        > Then write of great deeds worth the reading
        > Or do these great deeds, worth repeating.
        > -- Ben Franklin, from Poor Richard's Almanac
        > --
        > Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart at earthlink.net
        >
      • Lee Hart
        ... Actually, the 1804 s are just fine for *any* Elf where you have a ROM and can run some sort of monitor program. Computers like the VIP etc. work fine with
        Message 3 of 19 , Apr 10, 2012
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          On 4/10/2012 7:45 PM, awasson2001 wrote:
          > I think this would be a great use for those 1804 chips that were selling on Ebay last year fr about a buck a piece. I've got a couple of dozen that could be used in a Cosmac parallel super computer.

          Actually, the 1804's are just fine for *any* Elf where you have a ROM
          and can run some sort of monitor program. Computers like the VIP etc.
          work fine with the 1804 because they don't use LOAD mode.

          --
          Ingenuity gets you through times of no money better than money
          will get you through times of no ingenuity. -- Terry Pratchett
          --
          Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart at earthlink.net
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