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Re: Membership Card - Ultra Low Power Variant

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  • aa3nm
    Lee, Thanks for clarifying the debounce. Didn t realize I was using my bad eye when I squinted at that part of the schematic. Totally not sure how I didn t
    Message 1 of 16 , Mar 1, 2010
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      Lee,

      Thanks for clarifying the debounce. Didn't realize I was using my bad eye when I squinted at that part of the schematic. Totally not sure how I didn't see the feedback resistor as debounce.

      All good points on; the DIP Switches, layout, and on the memory power. I was thinking about all those points too. In the end, it's all a compromise anyway.

      My goal is to have a truly minimum power ELF that is as simple as possible with binary input and output. That being said, the tedium of programming anything more than ~50 bytes gets old very fast, even with toggle switches (been there too).

      Filling out the extra board space with a higher power and function expansion capability didn't seem to degrade my goal (as long as it could be disconnected). It would allow more flexibility of use. This is especially true if it enables easier loading of the 1/4 K low power RAM.

      The key point is to have the expansion board be unplugged from the micro-power ELF without loosing the 1/4 K RAM contents.

      Thanks for the inputs.

      BTW, I know you did a lot of work on the power consumption of the membership card - Do you have any sense on the consumption of this layout? I read on Herb's page that you were "running air" on the membershiip card overnight from the charge in the .047 uF cap, but adding the LCD display bumps up the power consumption (a lot less than LEDs but its still there).

      Steve


      --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:
      >
      > aa3nm wrote:
      > > I've taken Lee's schematic (available in the files section under
      > > Membershipcard LCD.pdf) and re-done it in the ExpressPCB schematic
      > > tool... to add the "8 bit binary LCD display" I described earlier.
      >
      > OK! Glad it was of use. I never got around to building this one, as so
      > few people seemed to be interested in it.
      >
      > > While at it, I decided to use a pair of DIP 4 wide SPDT switched for input.
      >
      > They are certainly small, but I think you'd get sick of operating them
      > pretty quickly.
      >
      > > In the process I discovered an issue with Lee's schematic – the input
      > > switch buffer for bit 0 should be U9D not 9A a second time. This
      > > puts the input on pin 10 and output as pin 9.
      >
      > Good catch. I fixed it on my copy.
      >
      > > Also, I notice there is no debounce on the Input switch SW1. I
      > > wonder about this and I'll hope Lee comments on this question.
      >
      > The switches *are* debounced. See the feedback resistors (R6, R14, R15)
      > around the buffers (U9E, U8E, U8F)? The switches (S1, S2, and S4) are
      > SPDT. When you move them from one position to the other, say, from the
      > NO (normally closed) to the NO (normally open) contact, the sequence of
      > events is:
      >
      > NC contact closed
      > NC contact bouncing open/closed
      > no connection from common to either NC or NO
      > NO contact bouncing open/closed
      > NO contact closed
      >
      > The 4503 buffer starts off with its input held low by the NC contact.
      > It's non-inverting, so the output is also low. The input and output
      > voltages are the same, so there is zero current in the resistor.
      >
      > Now you move the switch. When the NC contact starts bouncing
      > open/closed, the resistor holds the input low regardless of the switch
      > bounce. Power supply current is still zero.
      >
      > When neither NC nor NO contacts are closed, the resistor still holds the
      > 4503 output in its last state, still at zero power.
      >
      > When the NO contact first touches, it forces the 4503 input high in
      > spite of the resistor. There is a momentary pulse of current in the
      > resistor, for the time it takes the 4503 output to go high. Then the
      > current is zero again.
      >
      > While the NO contact is bouncing, the resistor holds the 4503 input and
      > output both high, at zero supply current.
      >
      > Thus, this circuit debounces the switches, and takes (essentially) zero
      > power to do it. This particular design was optimized for minimum power
      > consumption.
      >
      > > This space issue presents a bit of a problem for me… If I end up
      > > with a layout that is more than 11 sq-in.(meaning I cannot double the
      > > layout to get a pair of Micro Power ELFs on each board) what do I do
      > > with the extra space? It'd be a shame to have 15 sq in. of ELF on a
      > > 21 sq in. board.
      >
      > Depending on your layout skills, you could use both sides of the PCB for
      > parts, or mount parts underneath the 1802 or LCD display. But consider
      > that it will be harder to build (and to use!) if you make it too small.
      >
      > > So, my thinking is (so as not to waste the extra real-estate) to add
      > > a layout for a memory expansion card. I'm thinking 32k CMOS RAM and
      > > a couple of COMS 2K EEPROMS
      >
      > Unless you are very careful in the choice of memory chips, these newer
      > larger chips will use 100's of times more power than the rest of the
      > circuit. Almost all memory chips are optimized for maximum speed, not
      > minimum power!
      >
      > --
      > 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
      >
    • Lee Hart
      ... Yep; me too! But, it s a heck of a lot less painful with good switches. Use the best, easiest-to-use switches you can find. Notice that many of the
      Message 2 of 16 , Mar 1, 2010
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        aa3nm wrote:
        > My goal is to have a truly minimum power ELF that is as simple as
        > possible with binary input and output. That being said, the tedium
        > of programming anything more than ~50 bytes gets old very fast, even
        > with toggle switches (been there too).

        Yep; me too! But, it's a heck of a lot less painful with good switches.
        Use the best, easiest-to-use switches you can find. Notice that many of
        the traditional minicomputer front panels and organs use piano key like
        paddle switches.

        Same for a display. 8 raw binary LEDs are simple and cheap, but have few
        other attributes. The LCD display is lower power, and can produce a much
        nicer display.

        The small step up to a hex keypad and hex display is a big improvement
        over binary.

        You might also consider adding a circuit so a PC's parallel port can
        manipulate the front panel switches, as a way to automate the
        downloading process.

        Other thoughts: I don't think nearly enough creativity has been applied
        to the data entry and display issue. People quickly fixate on the
        antique QWERTY keyboard and video text displays. They work , but it
        takes a *lot* of hardware and software to support them.

        How about some of these alternative, just for fun... :-)

        - Morse code. A single switch contact is all you need for input.
        One bit to drive a speaker is all you need for output.
        The software to read and write Morse code is trivial (ham radio
        operators have written it many times, so examples are plentiful).
        Morse code (especially for numbers) isn't very hard to learn.

        - Voice. Pick 16 audio tones to represent each hex digit 0-F. Whistle
        or hum them to input data. A microphone and simple hardware/software
        interprets the tones. Play the same tones back to read the data.
        Has the advantage that it can also be saved and loaded with a tape
        recorder or PC sound card. You "sing" to your computer, and it "sings"
        back to you, like R2D2.

        - Calculator. A calculator has special keys for each function; + - /
        sin, square, etc. So, have keys labelled PHI GLO BR etc. and an
        alphanumeric display that shows assembler mnemonics.

        - Graphics and light pen. The display is a printed drawing of the 1802
        architecture, with a single LED at each register, and perhaps 24 LEDs
        showing the current memory address and its contents. A light pen
        (just a phototransistor in an old pen body) connects to an EFx line.
        Poke LEDs to turn them on/off, or move data to/from registers I/O
        and memory. The LEDs are multiplexed, so the time at which the light
        pen sees the pulse of light tells it which LED you pointed at.

        - Mouse with a view. House the ELF in an old computer mouse case.
        Attach a little plexiglass window that has an LED/LCD display.
        Set the mouse on a printed drawing of the computer architecture.
        As you move the mouse over a box on the drawing, the display on the
        mouse shows you the contents of that box. Aim at Register A, and it
        displays the contents of RA. Needs a mouse that doesn't "slip", or
        is reading codes printed on the page to know where it is. Use the
        mouse buttons to increment, decrement, scroll wheel for faster
        up/down changes, or to drag data from one register to another.

        - Analog meters and pots (a steampunk Elf). A pair of analog meters
        are marked 0 to 15v. A simple D/A converter converts the two hex
        digits you get from a typical Elf into two voltages ("A4" displays
        as 10v on the left meter, 4v on the right meter). Two pots or
        rotary switches under the meters are similarly labelled 0-15v.
        Use knife switches for the load/run switches.
        etc.

        > BTW, I know you did a lot of work on the power consumption of the
        > membership card - Do you have any sense on the consumption of this
        > layout? I read on Herb's page that you were "running air" on the
        > membershiip card overnight from the charge in the .047 uF cap, but
        > adding the LCD display bumps up the power consumption (a lot less
        > than LEDs but its still there).

        LCDs vary a lot. The older simpler ones (no backlight, no color, not
        multiplexed) are very low. The Lumex display on the LCD Elf I posted
        will probably run on less than 10 ua.

        Pullup resistors and memory chips are likely to be your the biggest
        problems. You need a design that avoids pullup resistors. The old 5101
        chips I used are true CMOS; zero power consumption when all inputs are
        static. but almost all modern RAMs (even those claimed to be CMOS) draw
        a significant supply current when chip selected even if all inputs are
        static.
        --
        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
      • aa3nm
        Lee, Thanks for the inputs, in time I think they ll be put to good use. I really like your Steam Punk idea. It s got me thinking about using Nixie Tubes for
        Message 3 of 16 , Mar 13, 2010
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          Lee,

          Thanks for the inputs, in time I think they'll be put to good use. I really like your Steam Punk idea. It's got me thinking about using Nixie Tubes for an Octal Display. Clearly not low power, nor "Spit & Coin" battery compatable, but it would be fun… Octal display would need a way to generate assembly listings in Octal to be easily read, but that could be managed a number of ways. Could be a fun project at some time in the future.

          I appreciate all your hard work with all the Membership card version you designed and posted. I had hoped to add value to those efforts by moving this one along as you and Herb are doing with the other version.

          In the interim, some things have come up that necessitate me setting this project aside for a while. No issues other than available time. I thought I had a small window and now other wicks have been turned up and that window has closed again. If I find another opportunity I may see if I can nudge it along a bit, hopefully with your support.

          I'm sure you recognize the scenario – it's all about hitting "critical mass" – getting enough momentum built up to move a project far enough along that finishing it is easier than boxing it up for later. This time, my goal of a basic ELF that could be operated, display and all from a "spit and coin" battery will have to hold on a while longer.

          If anyone else chooses to "nudge the bowling ball along a bit" feel free to ping me since one never knows how the available time can shift around.

          Best to all…

          Steve Gemeny
          AKA aa3nm

          --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:
          >
          > aa3nm wrote:
          > > My goal is to have a truly minimum power ELF that is as simple as
          > > possible with binary input and output. That being said, the tedium
          > > of programming anything more than ~50 bytes gets old very fast, even
          > > with toggle switches (been there too).
          >
          > Yep; me too! But, it's a heck of a lot less painful with good switches.
          > Use the best, easiest-to-use switches you can find. Notice that many of
          > the traditional minicomputer front panels and organs use piano key like
          > paddle switches.
          >
          > Same for a display. 8 raw binary LEDs are simple and cheap, but have few
          > other attributes. The LCD display is lower power, and can produce a much
          > nicer display.
          >
          > The small step up to a hex keypad and hex display is a big improvement
          > over binary.
          >
          > You might also consider adding a circuit so a PC's parallel port can
          > manipulate the front panel switches, as a way to automate the
          > downloading process.
          >
          > Other thoughts: I don't think nearly enough creativity has been applied
          > to the data entry and display issue. People quickly fixate on the
          > antique QWERTY keyboard and video text displays. They work , but it
          > takes a *lot* of hardware and software to support them.
          >
          > How about some of these alternative, just for fun... :-)
          >
          > - Morse code. A single switch contact is all you need for input.
          > One bit to drive a speaker is all you need for output.
          > The software to read and write Morse code is trivial (ham radio
          > operators have written it many times, so examples are plentiful).
          > Morse code (especially for numbers) isn't very hard to learn.
          >
          > - Voice. Pick 16 audio tones to represent each hex digit 0-F. Whistle
          > or hum them to input data. A microphone and simple hardware/software
          > interprets the tones. Play the same tones back to read the data.
          > Has the advantage that it can also be saved and loaded with a tape
          > recorder or PC sound card. You "sing" to your computer, and it "sings"
          > back to you, like R2D2.
          >
          > - Calculator. A calculator has special keys for each function; + - /
          > sin, square, etc. So, have keys labelled PHI GLO BR etc. and an
          > alphanumeric display that shows assembler mnemonics.
          >
          > - Graphics and light pen. The display is a printed drawing of the 1802
          > architecture, with a single LED at each register, and perhaps 24 LEDs
          > showing the current memory address and its contents. A light pen
          > (just a phototransistor in an old pen body) connects to an EFx line.
          > Poke LEDs to turn them on/off, or move data to/from registers I/O
          > and memory. The LEDs are multiplexed, so the time at which the light
          > pen sees the pulse of light tells it which LED you pointed at.
          >
          > - Mouse with a view. House the ELF in an old computer mouse case.
          > Attach a little plexiglass window that has an LED/LCD display.
          > Set the mouse on a printed drawing of the computer architecture.
          > As you move the mouse over a box on the drawing, the display on the
          > mouse shows you the contents of that box. Aim at Register A, and it
          > displays the contents of RA. Needs a mouse that doesn't "slip", or
          > is reading codes printed on the page to know where it is. Use the
          > mouse buttons to increment, decrement, scroll wheel for faster
          > up/down changes, or to drag data from one register to another.
          >
          > - Analog meters and pots (a steampunk Elf). A pair of analog meters
          > are marked 0 to 15v. A simple D/A converter converts the two hex
          > digits you get from a typical Elf into two voltages ("A4" displays
          > as 10v on the left meter, 4v on the right meter). Two pots or
          > rotary switches under the meters are similarly labelled 0-15v.
          > Use knife switches for the load/run switches.
          > etc.
          >
          > > BTW, I know you did a lot of work on the power consumption of the
          > > membership card - Do you have any sense on the consumption of this
          > > layout? I read on Herb's page that you were "running air" on the
          > > membershiip card overnight from the charge in the .047 uF cap, but
          > > adding the LCD display bumps up the power consumption (a lot less
          > > than LEDs but its still there).
          >
          > LCDs vary a lot. The older simpler ones (no backlight, no color, not
          > multiplexed) are very low. The Lumex display on the LCD Elf I posted
          > will probably run on less than 10 ua.
          >
          > Pullup resistors and memory chips are likely to be your the biggest
          > problems. You need a design that avoids pullup resistors. The old 5101
          > chips I used are true CMOS; zero power consumption when all inputs are
          > static. but almost all modern RAMs (even those claimed to be CMOS) draw
          > a significant supply current when chip selected even if all inputs are
          > static.
          > --
          > 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
          >
        • awasson2001
          Steve, I have a box of vintage Numitron tubes that I was thinking would make a great SteamPunk ELF display. Not as nice a display as the Nixi s but much lower
          Message 4 of 16 , Mar 13, 2010
          • 0 Attachment
            Steve, I have a box of vintage Numitron tubes that I was thinking would make a great SteamPunk ELF display. Not as nice a display as the Nixi's but much lower consumption I would expect.

            If I make anything happen with them, I'll post a picture to the board.

            Andrew






            --- In cosmacelf@yahoogroups.com, "aa3nm" <steve@...> wrote:
            >
            > Lee,
            >
            > Thanks for the inputs, in time I think they'll be put to good use. I really like your Steam Punk idea. It's got me thinking about using Nixie Tubes for an Octal Display. Clearly not low power, nor "Spit & Coin" battery compatable, but it would be fun… Octal display would need a way to generate assembly listings in Octal to be easily read, but that could be managed a number of ways. Could be a fun project at some time in the future.
            >
            > I appreciate all your hard work with all the Membership card version you designed and posted. I had hoped to add value to those efforts by moving this one along as you and Herb are doing with the other version.
            >
            > In the interim, some things have come up that necessitate me setting this project aside for a while. No issues other than available time. I thought I had a small window and now other wicks have been turned up and that window has closed again. If I find another opportunity I may see if I can nudge it along a bit, hopefully with your support.
            >
            > I'm sure you recognize the scenario – it's all about hitting "critical mass" – getting enough momentum built up to move a project far enough along that finishing it is easier than boxing it up for later. This time, my goal of a basic ELF that could be operated, display and all from a "spit and coin" battery will have to hold on a while longer.
            >
            > If anyone else chooses to "nudge the bowling ball along a bit" feel free to ping me since one never knows how the available time can shift around.
            >
            > Best to all…
            >
            > Steve Gemeny
            > AKA aa3nm
            >
            > --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@> wrote:
            > >
            > > aa3nm wrote:
            > > > My goal is to have a truly minimum power ELF that is as simple as
            > > > possible with binary input and output. That being said, the tedium
            > > > of programming anything more than ~50 bytes gets old very fast, even
            > > > with toggle switches (been there too).
            > >
            > > Yep; me too! But, it's a heck of a lot less painful with good switches.
            > > Use the best, easiest-to-use switches you can find. Notice that many of
            > > the traditional minicomputer front panels and organs use piano key like
            > > paddle switches.
            > >
            > > Same for a display. 8 raw binary LEDs are simple and cheap, but have few
            > > other attributes. The LCD display is lower power, and can produce a much
            > > nicer display.
            > >
            > > The small step up to a hex keypad and hex display is a big improvement
            > > over binary.
            > >
            > > You might also consider adding a circuit so a PC's parallel port can
            > > manipulate the front panel switches, as a way to automate the
            > > downloading process.
            > >
            > > Other thoughts: I don't think nearly enough creativity has been applied
            > > to the data entry and display issue. People quickly fixate on the
            > > antique QWERTY keyboard and video text displays. They work , but it
            > > takes a *lot* of hardware and software to support them.
            > >
            > > How about some of these alternative, just for fun... :-)
            > >
            > > - Morse code. A single switch contact is all you need for input.
            > > One bit to drive a speaker is all you need for output.
            > > The software to read and write Morse code is trivial (ham radio
            > > operators have written it many times, so examples are plentiful).
            > > Morse code (especially for numbers) isn't very hard to learn.
            > >
            > > - Voice. Pick 16 audio tones to represent each hex digit 0-F. Whistle
            > > or hum them to input data. A microphone and simple hardware/software
            > > interprets the tones. Play the same tones back to read the data.
            > > Has the advantage that it can also be saved and loaded with a tape
            > > recorder or PC sound card. You "sing" to your computer, and it "sings"
            > > back to you, like R2D2.
            > >
            > > - Calculator. A calculator has special keys for each function; + - /
            > > sin, square, etc. So, have keys labelled PHI GLO BR etc. and an
            > > alphanumeric display that shows assembler mnemonics.
            > >
            > > - Graphics and light pen. The display is a printed drawing of the 1802
            > > architecture, with a single LED at each register, and perhaps 24 LEDs
            > > showing the current memory address and its contents. A light pen
            > > (just a phototransistor in an old pen body) connects to an EFx line.
            > > Poke LEDs to turn them on/off, or move data to/from registers I/O
            > > and memory. The LEDs are multiplexed, so the time at which the light
            > > pen sees the pulse of light tells it which LED you pointed at.
            > >
            > > - Mouse with a view. House the ELF in an old computer mouse case.
            > > Attach a little plexiglass window that has an LED/LCD display.
            > > Set the mouse on a printed drawing of the computer architecture.
            > > As you move the mouse over a box on the drawing, the display on the
            > > mouse shows you the contents of that box. Aim at Register A, and it
            > > displays the contents of RA. Needs a mouse that doesn't "slip", or
            > > is reading codes printed on the page to know where it is. Use the
            > > mouse buttons to increment, decrement, scroll wheel for faster
            > > up/down changes, or to drag data from one register to another.
            > >
            > > - Analog meters and pots (a steampunk Elf). A pair of analog meters
            > > are marked 0 to 15v. A simple D/A converter converts the two hex
            > > digits you get from a typical Elf into two voltages ("A4" displays
            > > as 10v on the left meter, 4v on the right meter). Two pots or
            > > rotary switches under the meters are similarly labelled 0-15v.
            > > Use knife switches for the load/run switches.
            > > etc.
            > >
            > > > BTW, I know you did a lot of work on the power consumption of the
            > > > membership card - Do you have any sense on the consumption of this
            > > > layout? I read on Herb's page that you were "running air" on the
            > > > membershiip card overnight from the charge in the .047 uF cap, but
            > > > adding the LCD display bumps up the power consumption (a lot less
            > > > than LEDs but its still there).
            > >
            > > LCDs vary a lot. The older simpler ones (no backlight, no color, not
            > > multiplexed) are very low. The Lumex display on the LCD Elf I posted
            > > will probably run on less than 10 ua.
            > >
            > > Pullup resistors and memory chips are likely to be your the biggest
            > > problems. You need a design that avoids pullup resistors. The old 5101
            > > chips I used are true CMOS; zero power consumption when all inputs are
            > > static. but almost all modern RAMs (even those claimed to be CMOS) draw
            > > a significant supply current when chip selected even if all inputs are
            > > static.
            > > --
            > > 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
            > >
            >
          • didio4@aol.com
            If you need some nixies, I bought a couple of hundred last year, along with the driver chips. Would be willing to donate for the cause. Gary Sent via
            Message 5 of 16 , Mar 13, 2010
            • 0 Attachment
              If you need some nixies, I bought a couple of hundred last year, along with the driver chips. Would be willing to donate for the cause.

              Gary
              Sent via BlackBerry by AT&T

              -----Original Message-----
              From: "awasson2001" <awasson@...>
              Date: Sat, 13 Mar 2010 19:19:54
              To: <cosmacelf@yahoogroups.com>
              Subject: [cosmacelf] Re: Membership Card - Ultra Low Power Variant

              Steve, I have a box of vintage Numitron tubes that I was thinking would make a great SteamPunk ELF display. Not as nice a display as the Nixi's but much lower consumption I would expect.

              If I make anything happen with them, I'll post a picture to the board.

              Andrew






              --- In cosmacelf@yahoogroups.com, "aa3nm" <steve@...> wrote:
              >
              > Lee,
              >
              > Thanks for the inputs, in time I think they'll be put to good use. I really like your Steam Punk idea. It's got me thinking about using Nixie Tubes for an Octal Display. Clearly not low power, nor "Spit & Coin" battery compatable, but it would be fun� Octal display would need a way to generate assembly listings in Octal to be easily read, but that could be managed a number of ways. Could be a fun project at some time in the future.
              >
              > I appreciate all your hard work with all the Membership card version you designed and posted. I had hoped to add value to those efforts by moving this one along as you and Herb are doing with the other version.
              >
              > In the interim, some things have come up that necessitate me setting this project aside for a while. No issues other than available time. I thought I had a small window and now other wicks have been turned up and that window has closed again. If I find another opportunity I may see if I can nudge it along a bit, hopefully with your support.
              >
              > I'm sure you recognize the scenario � it's all about hitting "critical mass" � getting enough momentum built up to move a project far enough along that finishing it is easier than boxing it up for later. This time, my goal of a basic ELF that could be operated, display and all from a "spit and coin" battery will have to hold on a while longer.
              >
              > If anyone else chooses to "nudge the bowling ball along a bit" feel free to ping me since one never knows how the available time can shift around.
              >
              > Best to all�
              >
              > Steve Gemeny
              > AKA aa3nm
              >
              > --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@> wrote:
              > >
              > > aa3nm wrote:
              > > > My goal is to have a truly minimum power ELF that is as simple as
              > > > possible with binary input and output. That being said, the tedium
              > > > of programming anything more than ~50 bytes gets old very fast, even
              > > > with toggle switches (been there too).
              > >
              > > Yep; me too! But, it's a heck of a lot less painful with good switches.
              > > Use the best, easiest-to-use switches you can find. Notice that many of
              > > the traditional minicomputer front panels and organs use piano key like
              > > paddle switches.
              > >
              > > Same for a display. 8 raw binary LEDs are simple and cheap, but have few
              > > other attributes. The LCD display is lower power, and can produce a much
              > > nicer display.
              > >
              > > The small step up to a hex keypad and hex display is a big improvement
              > > over binary.
              > >
              > > You might also consider adding a circuit so a PC's parallel port can
              > > manipulate the front panel switches, as a way to automate the
              > > downloading process.
              > >
              > > Other thoughts: I don't think nearly enough creativity has been applied
              > > to the data entry and display issue. People quickly fixate on the
              > > antique QWERTY keyboard and video text displays. They work , but it
              > > takes a *lot* of hardware and software to support them.
              > >
              > > How about some of these alternative, just for fun... :-)
              > >
              > > - Morse code. A single switch contact is all you need for input.
              > > One bit to drive a speaker is all you need for output.
              > > The software to read and write Morse code is trivial (ham radio
              > > operators have written it many times, so examples are plentiful).
              > > Morse code (especially for numbers) isn't very hard to learn.
              > >
              > > - Voice. Pick 16 audio tones to represent each hex digit 0-F. Whistle
              > > or hum them to input data. A microphone and simple hardware/software
              > > interprets the tones. Play the same tones back to read the data.
              > > Has the advantage that it can also be saved and loaded with a tape
              > > recorder or PC sound card. You "sing" to your computer, and it "sings"
              > > back to you, like R2D2.
              > >
              > > - Calculator. A calculator has special keys for each function; + - /
              > > sin, square, etc. So, have keys labelled PHI GLO BR etc. and an
              > > alphanumeric display that shows assembler mnemonics.
              > >
              > > - Graphics and light pen. The display is a printed drawing of the 1802
              > > architecture, with a single LED at each register, and perhaps 24 LEDs
              > > showing the current memory address and its contents. A light pen
              > > (just a phototransistor in an old pen body) connects to an EFx line.
              > > Poke LEDs to turn them on/off, or move data to/from registers I/O
              > > and memory. The LEDs are multiplexed, so the time at which the light
              > > pen sees the pulse of light tells it which LED you pointed at.
              > >
              > > - Mouse with a view. House the ELF in an old computer mouse case.
              > > Attach a little plexiglass window that has an LED/LCD display.
              > > Set the mouse on a printed drawing of the computer architecture.
              > > As you move the mouse over a box on the drawing, the display on the
              > > mouse shows you the contents of that box. Aim at Register A, and it
              > > displays the contents of RA. Needs a mouse that doesn't "slip", or
              > > is reading codes printed on the page to know where it is. Use the
              > > mouse buttons to increment, decrement, scroll wheel for faster
              > > up/down changes, or to drag data from one register to another.
              > >
              > > - Analog meters and pots (a steampunk Elf). A pair of analog meters
              > > are marked 0 to 15v. A simple D/A converter converts the two hex
              > > digits you get from a typical Elf into two voltages ("A4" displays
              > > as 10v on the left meter, 4v on the right meter). Two pots or
              > > rotary switches under the meters are similarly labelled 0-15v.
              > > Use knife switches for the load/run switches.
              > > etc.
              > >
              > > > BTW, I know you did a lot of work on the power consumption of the
              > > > membership card - Do you have any sense on the consumption of this
              > > > layout? I read on Herb's page that you were "running air" on the
              > > > membershiip card overnight from the charge in the .047 uF cap, but
              > > > adding the LCD display bumps up the power consumption (a lot less
              > > > than LEDs but its still there).
              > >
              > > LCDs vary a lot. The older simpler ones (no backlight, no color, not
              > > multiplexed) are very low. The Lumex display on the LCD Elf I posted
              > > will probably run on less than 10 ua.
              > >
              > > Pullup resistors and memory chips are likely to be your the biggest
              > > problems. You need a design that avoids pullup resistors. The old 5101
              > > chips I used are true CMOS; zero power consumption when all inputs are
              > > static. but almost all modern RAMs (even those claimed to be CMOS) draw
              > > a significant supply current when chip selected even if all inputs are
              > > static.
              > > --
              > > 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]
            • aa3nm
              Andrew, Let me know if you want a few Nixies to play with. I have several different styles and enough quantity to spread a few around. There s also a wide
              Message 6 of 16 , Mar 13, 2010
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                Andrew, Let me know if you want a few Nixies to play with. I have several different styles and enough quantity to spread a few around.

                There's also a wide selection on that online auction place...

                have fun,

                Steve

                --- In cosmacelf@yahoogroups.com, "awasson2001" <awasson@...> wrote:
                >
                > Steve, I have a box of vintage Numitron tubes that I was thinking would make a great SteamPunk ELF display. Not as nice a display as the Nixi's but much lower consumption I would expect.
                >
                > If I make anything happen with them, I'll post a picture to the board.
                >
                > Andrew
                >
                >
                >
              • Lee Hart
                ... Yeah, that one is certainly the most outrageous. Probably also the least practical. Maybe that would make it the most fun. :-) ... That could work, though
                Message 7 of 16 , Mar 15, 2010
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                  aa3nm wrote:
                  > I really like your Steam Punk idea.

                  Yeah, that one is certainly the most outrageous. Probably also the least
                  practical. Maybe that would make it the most fun. :-)

                  > It's got me thinking about using Nixie Tubes for an Octal Display.

                  That could work, though octal is awkward with the 1802 instruction set.
                  Most opcodes have 1-of-16 commands followed by 1-of-16 registers to do
                  it to.

                  Maybe use split octal. Display a byte as two nibbles. Display each
                  nibble as a pair of digits, 00 to 15. So an instruction like "F8"
                  displays as "15.08".

                  > I appreciate all your hard work with all the Membership card version
                  > you designed and posted. I had hoped to add value to those efforts by
                  > moving this one along as you and Herb are doing with the other version.

                  No problem! Anything that is fun and creative is worthwhile, even if
                  just for its own sake. :-)

                  --
                  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
                • Lee Hart
                  ... Ah; Numitrons are 7-segment displays, right? Basically a light bulb with seven long skinny filament wires. Now what you d call efficient , but they are
                  Message 8 of 16 , Mar 15, 2010
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                    awasson2001 wrote:
                    > Steve, I have a box of vintage Numitron tubes that I was thinking would make
                    > a great SteamPunk ELF display. Not as nice a display as the Nixi's but much
                    > lower consumption I would expect.
                    >
                    > If I make anything happen with them, I'll post a picture to the board.

                    Ah; Numitrons are 7-segment displays, right? Basically a light bulb with
                    seven long skinny filament wires. Now what you'd call "efficient", but
                    they are easy to drive and make it easy to produce a hex display. Nixies
                    would probably use less power.

                    For that matter, nothing says you can't use seven NE-2 neon bulbs,
                    oriented to form a 7-segment display. :-)

                    --
                    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
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