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Kaypro 4 ROM speed

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  • Mike Loewen
    What speed 2764 EPROM is required for a Kaypro 4 or Kaypro 10? 250ns? 200ns? I m want to try an Advent TurboROM. Mike Loewen mloewen@cpumagic.scol.pa.us
    Message 1 of 3 , Aug 25, 2014
      What speed 2764 EPROM is required for a Kaypro 4 or Kaypro 10? 250ns?
      200ns? I'm want to try an Advent TurboROM.


      Mike Loewen mloewen@...
      Old Technology http://q7.neurotica.com/Oldtech/
    • Dan Roganti
      On Mon, Aug 25, 2014 at 11:39 AM, Mike Loewen mloewen@cpumagic.scol.pa.us ... ​I don t think the speed grade would be any different than the original Eprom
      Message 2 of 3 , Aug 25, 2014



        On Mon, Aug 25, 2014 at 11:39 AM, Mike Loewen mloewen@... [midatlanticretro] <midatlanticretro@yahoogroups.com> wrote:

            What speed 2764 EPROM is required for a Kaypro 4 or Kaypro 10?  250ns?
        200ns?  I'm want to try an Advent TurboROM.

        ​I don't think the speed grade would be any different than the original Eprom
        From what I see, the Advent TurboRom was just a Rom upgrade, with the extra addr decode for the denser part.
        The Kaypro 2 and 4 have a 2.5Mhz Z80
        My Kaypro 2 has a MM2716Q-1 Eprom for the Boot Rom which is a 350ns part
        Any faster speed grade doesn't hurt, the memory access is still the same number of cycles.
        It's when you have a slower part, then you insert a Wait to increase the cycles to support a longer access time.




      • Dan Roganti
        ... ​whoops, tired eyes this late again the Kaypro 4 is 4mhz, so Z80 cycle time is 250nsec Better to get 200nsec part for Eprom ​ On Tue, Aug 26, 2014 at
        Message 3 of 3 , Aug 25, 2014



          On Tue, Aug 26, 2014 at 12:25 AM, Dan Roganti <ragooman@...> wrote:



          On Mon, Aug 25, 2014 at 11:39 AM, Mike Loewen mloewen@... [midatlanticretro] <midatlanticretro@yahoogroups.com> wrote:

              What speed 2764 EPROM is required for a Kaypro 4 or Kaypro 10?  250ns?
          200ns?  I'm want to try an Advent TurboROM.

          ​I don't think the speed grade would be any different than the original Eprom
          From what I see, the Advent TurboRom was just a Rom upgrade, with the extra addr decode for the denser part.
          The Kaypro 2 and 4 have a 2.5Mhz Z80
          My Kaypro 2 has a MM2716Q-1 Eprom for the Boot Rom which is a 350ns part
          Any faster speed grade doesn't hurt, the memory access is still the same number of cycles.
          It's when you have a slower part, then you insert a Wait to increase the cycles to support a longer access time.

          ​whoops, tired eyes this late again
          the Kaypro 4 is 4mhz, so Z80 cycle time is 250nsec
          Better to get 200nsec part for Eprom


           
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