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Re: [cosmacelf] is it possible to stack memory chips with the VIP or other ELF's ?

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  • Ray Sills
    Hi Jim: The VIP will support up to 4K RAM on the board itself. Some early models only came with 2K, so one of the first upgrades was to add the other 2K.
    Message 1 of 8 , Feb 3, 2011
      Hi Jim:

      The VIP will support up to 4K RAM on the board itself. Some early
      models only came with 2K, so one of the first upgrades was to add the
      other 2K. After that, it's easiest to add RAM via the expansion
      connector.. all the address select lines are there, along with the
      data and address bus.

      The very early VIPs used 9131 RAM chips, but later versions used the
      2114, which was much more common.

      BTW, I used that chip-stack technique to expand a Radio Shack Color
      computer's RAM from 16K to 32 K.

      73 de Ray

      On Feb 3, 2011, at 8:22 PM, jehall1442596 wrote:

      > Hello:
      > In my past and a way around getting more memory on my Atari-130xe I
      > had to resort to stacking memory chips on top of each other to
      > change the configuration of memory from say 64k to 128k ? I dont
      > know if it is possible or that it can be done seeing at least on
      > the VIP you have very few memory chips and the thought is a bit odd
      > to the thought.
      > jim
      >
      >
    • karl_schultz
      I think I did the same thing. I wanted to build a 4K board out of 1K x 1 chips, 2102, I think. Anyway, the thought of wire-wrapping 16-pins on 32 chips did
      Message 2 of 8 , Feb 4, 2011
        I think I did the same thing. I wanted to build a 4K board out of 1K x 1 chips, 2102, I think. Anyway, the thought of wire-wrapping 16-pins on 32 chips did not appeal to me. So I made 4 stacks of 8 chips, soldering all the pins together. I think I had to bend out the DataIn and DataOut pins so that they did not get soldered with the rest of the stack, and I wired them down to the bus somehow. Long time ago. Sounds crazy, but it worked. I suppose that heat dissipation never got to be a problem.

        --- In cosmacelf@yahoogroups.com, "the-eagle@..." <the-eagle@...> wrote:
        >
        > Jim,
        > Back in the day, when I have a Cosmac Elf-II, I use to stack the 1K by 1 memory chips upon each other. This was not a problem as long as you lifted the CE (Chip Enable) line from each of your stacked memory chips and tied them (the CE lines) together and ran them to your built memory (address decoder) select line.
        >
        > Chuck
        >
        >
        > --- In cosmacelf@yahoogroups.com, "jehall1442596" <jehall1442596@> wrote:
        > >
        > > Hello:
        > > In my past and a way around getting more memory on my Atari-130xe I had to resort to stacking memory chips on top of each other to change the configuration of memory from say 64k to 128k ? I dont know if it is possible or that it can be done seeing at least on the VIP you have very few memory chips and the thought is a bit odd to the thought.
        > > jim
        > >
        >
      • Lee Hart
        ... I remember doing the same thing in the early days of small memory chips. There is a clever technique called cordwood construction. It gets around the
        Message 3 of 8 , Feb 4, 2011
          On 2/4/2011 9:29 AM, karl_schultz wrote:
          > I think I did the same thing. I wanted to build a 4K board out of 1K
          > x 1 chips, 2102, I think. Anyway, the thought of wire-wrapping
          > 16-pins on 32 chips did not appeal to me. So I made 4 stacks of 8
          > chips, soldering all the pins together. I think I had to bend out
          > the DataIn and DataOut pins so that they did not get soldered with
          > the rest of the stack, and I wired them down to the bus somehow.
          > Long time ago. Sounds crazy, but it worked. I suppose that heat
          > dissipation never got to be a problem.

          I remember doing the same thing in the early days of small memory chips.

          There is a clever technique called 'cordwood' construction. It gets
          around the limitations of single-sided boards, and packs the parts on
          edge (like "cordwood") for extremely high density.

          Instead of a double-sided PC board, you make two single-sided boards.
          The leads of DIPs are bent flat (like a "squished bug"). The pins on one
          side of the DIP go into holes on the bottom PC board; the pins on the
          other side of the DIP go into holes on the top PC board. All resistors,
          capacitors, and diodes are stood on end, so one lead will go into one
          board, and the other lead goes into the other board. Straight pieces of
          wire serve as jumpers to "stitch" the two boards together.

          I used this style of construction with two perf boards to stack groups
          of memory chips together. It takes more planning, but worked out very well!
          --
          Lee A. Hart | Ring the bells that still can ring
          814 8th Ave N | Forget the perfect offering
          Sartell MN 56377 | There is a crack in everything
          leeahart earthlink.net | That's how the light gets in -- Leonard Cohen
        • Jim Hall
          I was thinking of stack chips but is the 2101chip hard to find? I always thought you could use 2114 s as in a extra board, seeing I can find those. Hmmm I am
          Message 4 of 8 , Feb 4, 2011
            I was thinking of stack chips but is the 2101chip hard to find? I always thought
            you could use 2114's as in a extra board, seeing I can find those. Hmmm I am
            starting to look.....

             



            ________________________________
            From: karl_schultz <Karl.W.Schultz@...>
            To: cosmacelf@yahoogroups.com
            Sent: Fri, February 4, 2011 10:29:46 AM
            Subject: [cosmacelf] Re: is it possible to stack memory chips with the VIP or
            other ELF's ?

             
            I think I did the same thing. I wanted to build a 4K board out of 1K x 1 chips,
            2102, I think. Anyway, the thought of wire-wrapping 16-pins on 32 chips did not
            appeal to me. So I made 4 stacks of 8 chips, soldering all the pins together. I
            think I had to bend out the DataIn and DataOut pins so that they did not get
            soldered with the rest of the stack, and I wired them down to the bus somehow.
            Long time ago. Sounds crazy, but it worked. I suppose that heat dissipation
            never got to be a problem.


            --- In cosmacelf@yahoogroups.com, "the-eagle@..." <the-eagle@...> wrote:
            >
            > Jim,
            > Back in the day, when I have a Cosmac Elf-II, I use to stack the 1K by 1 memory
            >chips upon each other. This was not a problem as long as you lifted the CE (Chip
            >Enable) line from each of your stacked memory chips and tied them (the CE lines)
            >together and ran them to your built memory (address decoder) select line.
            >
            > Chuck
            >
            >
            > --- In cosmacelf@yahoogroups.com, "jehall1442596" <jehall1442596@> wrote:
            > >
            > > Hello:
            > > In my past and a way around getting more memory on my Atari-130xe I had to
            >resort to stacking memory chips on top of each other to change the configuration
            >of memory from say 64k to 128k ? I dont know if it is possible or that it can be
            >done seeing at least on the VIP you have very few memory chips and the thought
            >is a bit odd to the thought.
            > > jim
            > >
            >







            [Non-text portions of this message have been removed]
          • Lee Hart
            ... No, no... the way to do it today is to get a single bytewide RAM (for example a 62256 32K x 8). Build a plug-in card for the expansion connector. Put this
            Message 5 of 8 , Feb 4, 2011
              On 2/4/2011 2:29 PM, Jim Hall wrote:
              > I was thinking of stack chips but is the 2101chip hard to find? I always thought
              > you could use 2114's as in a extra board, seeing I can find those. Hmmm I am
              > starting to look.....

              No, no... the way to do it today is to get a single bytewide RAM (for
              example a 62256 32K x 8). Build a plug-in card for the expansion
              connector. Put this chip, and an address decoder (such as a 74HC138) on
              it. Plug it in.

              This way, you don't have to modify the VIP at all, and the car is easy
              to build.

              --
              Lee A. Hart | Ring the bells that still can ring
              814 8th Ave N | Forget the perfect offering
              Sartell MN 56377 | There is a crack in everything
              leeahart earthlink.net | That's how the light gets in -- Leonard Cohen
            • Jim Hall
              Hello: I am going to start looking for the chips and see if I can get some. Seems I need to look over what I need. VIP Bus system ? Pin out of the bus is some
              Message 6 of 8 , Feb 4, 2011
                Hello:

                I am going to start looking for the chips and see if I can get some. Seems I
                need to look over what I need.


                VIP Bus system ? Pin out of the bus is some place, my next voyage into the
                internet.

                jim




                ________________________________
                From: Lee Hart <leeahart@...>
                To: cosmacelf@yahoogroups.com
                Sent: Fri, February 4, 2011 4:22:04 PM
                Subject: Re: [cosmacelf] Re: is it possible to stack memory chips with the VIP
                or other ELF's ?

                 
                On 2/4/2011 2:29 PM, Jim Hall wrote:
                > I was thinking of stack chips but is the 2101chip hard to find? I always
                >thought
                > you could use 2114's as in a extra board, seeing I can find those. Hmmm I am
                > starting to look.....

                No, no... the way to do it today is to get a single bytewide RAM (for
                example a 62256 32K x 8). Build a plug-in card for the expansion
                connector. Put this chip, and an address decoder (such as a 74HC138) on
                it. Plug it in.

                This way, you don't have to modify the VIP at all, and the car is easy
                to build.

                --
                Lee A. Hart | Ring the bells that still can ring
                814 8th Ave N | Forget the perfect offering
                Sartell MN 56377 | There is a crack in everything
                leeahart earthlink.net | That's how the light gets in -- Leonard Cohen






                [Non-text portions of this message have been removed]
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