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Re: Improving my Elf?

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  • schultdw
    I recently discovered this group and have been thinking about rebuilding my old ELF, or a reasonable facsimally thereof. But like you, I am not excited by the
    Message 1 of 21 , Sep 9, 2003
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      I recently discovered this group and have been thinking about
      rebuilding my old ELF, or a reasonable facsimally thereof. But like
      you, I am not excited by the possibility of loading code with toggle
      switches. I remember doing that all too well.

      It occured to me that it might be possible to program a
      microcontroller (the PIC 16F876 springs to mind) as a bootloader.
      Using the serial port to download a program file from a host computer
      and then use the LOAD mode of the 1802 to stuff the program into memory.

      I need to sit down with the data sheets and check the timing to see if
      this idea will work.


      Radio Shack carries wire wrap wire.


      --- In cosmacelf@yahoogroups.com, Philip Pemberton <philpem@d...> wrote:
      > Hi,
      > I've just pulled my Cosmac Elf out of storage and loaded the
      "Starship"
      > demo into it. After tweaking the Vertical Hold control on my
      mini-TV, I've
      > managed to get a stable picture from the Pixie (CDP1861) IC.
      > Now, I've hit a bit of a snag. Loading COSMAC code with the
      toggles is hard
      > work. Is it worth trying to rig up a hex keypad for my Elf? I've got the
      > equipment to do single- and double-sided PCBs (excluding
      plated-through holes
      > and tinplating). Just how much work would an add-on of this kind
      involve?
      > I don't have any wirewrap wire left either, so adding to the Elf
      is going
      > to be a bit difficult. Does anyone know of a supplier of low-cost
      Kynar (or
      > similar) wirewrap wire, preferably based in the UK?
      > I was also thinking of adding an upper address latch and EPROM
      socket (keep
      > the Starship program in RAM, then have a Relocator that loads the
      code into
      > low RAM). Adding a second RAM may also be an option.
      > At the moment, I'm toying with the idea of installing an expansion bus
      > connector, most likely a 0.1" pin header or a DIN41612. Is there a
      defined
      > standard for Elf interface connectors?
      >
      > Thanks.
      > --
      > Phil. | Acorn Risc PC600 Mk3, SA202,
      64MB, 6GB,
      > philpem@d... | ViewFinder, Ethernet (Acorn AEH62),
      > http://www.philpem.dsl.pipex.com/ | 8xCD, framegrabber, Teletext
      > (A)bort (R)etry (W)ire up to a Tesla Coil and watch it glow.
    • joshbensadon
      Hi Phil, Yes, those switches are a pain. Using hex keypad is a pain too when you still need to manually reload. Perhaps you might want to go with a tape
      Message 2 of 21 , Sep 9, 2003
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        Hi Phil,

        Yes, those switches are a pain. Using hex keypad is a
        pain too when you still need to manually reload.
        Perhaps you might want to go with a tape save/load?
        On my 2nd Elf, I added RS-232, so I may upload programs
        in .hex format using any terminal program. I can share
        that with you, if you want. It will need an Eprom and
        an address latch with decoding.
        The way I look at it...
        1. hex keypad needs some wiring, still need to reload
        2. tape interface needs little wiring, still need to toggle
        in a save/restore program.
        3. RS-232 needs a lot of wiring, but lets you use any
        standard terminal program

        Here's another idea...
        4. Parrallel connection. Uses little wiring.

        If you like the idea, I would love to be of some help.
        Here's what I had in mind. Using the LPT port of your
        computer to "enter" data into the Elf. First, we need
        to share the input switches, so, add 10K resistors
        between the switchs and the 4016's. Connect the 4016's
        to pins 2-9 of the DB connector (data). Break the clock
        line to the 4013 (pin 11) and put in a 3 pole jumper.
        The jumper will allow either the input switch to clock
        the data in, or connects the 4013 to pin 1 of the DB (Strobe).
        Of course, connect pin 25 of the DB to ground.

        If you like the idea, I can write a program that will
        "input a program" to the Elf via the LPT port.

        So... what do you think?

        Josh
      • joshbensadon
        I was just thinking about exactly what value resistor to add. The idea is to allow the LPT port to OVERRIDE any switch setting when the LPT data port is
        Message 3 of 21 , Sep 9, 2003
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          I was just thinking about exactly what value
          resistor to add. The idea is to allow the LPT
          port to OVERRIDE any switch setting when the
          LPT data port is active, and to allow the switch
          to continue to work when the LPT data port is
          in hi-z state. You might need to try different
          values, 10k was just a value that sounds like
          it might work.
          If this fails to work, ie the Hi-z doesn't allow
          the switches to work, then perhaps you might
          only need to unplug the DB connector before
          toggling the RUN switch? Another idea that
          will definitely work, but requires more wiring
          is using a couple of diodes and a resistor to
          make a "diode OR gate" like what was done for
          the N2/Load line.
          I prefer the simple resistor, even if you have
          to unplug the DB connector... simple is better.

          Josh
        • J.C. Wren
          I ve drawn some schematics and written the PAL equations for an Atmel Mega8 based loader/debugger. Basically, you should be able to do anything you could do
          Message 4 of 21 , Sep 9, 2003
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            I've drawn some schematics and written the PAL equations for an Atmel Mega8
            based loader/debugger. Basically, you should be able to do anything you
            could do from the standard switches (load/store/inspect/run/stop/reset, etc).

            I just haven't had time to do a layout on it. And it should work on the bus
            of any existing 1802 system, with the exception of the write signal (I think)
            needs to be looped through the adapter.

            Another project in the works is a PCB for an 1802. I envision (for the sake
            of contrast) an 1802, 1861 option, 1802 UART (number escapes me at the
            moment), 128K flash, 128K RAM, and a Xilinx or other FPGA that allows any
            sort of FLASH/RAM memory arrangement down to the 1K page size (basically, a
            large dynamic address table). Also included would be an interface to a
            compact flash card (just think: One 64MB flash card could hold every 1802
            program every released, in all likelyhood).

            The monitor would support programming the flash part, multiple loader images
            in flash (I envision a Forth core monitor for at least one of them). If we
            could find a copy of the 1802 DOS (name escapes me, the one on the RCA
            development system), I'd like to make it runnable.

            There might be a few legacy peripherials, just for old times sake. Perhaps
            1852s, additional UARTs, whatever.

            --John
          • joshbensadon
            John, ... 1854? Josh
            Message 5 of 21 , Sep 9, 2003
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              John,

              > 1802 UART (number escapes me at the moment)

              1854?

              Josh
            • Gemeny, Steve
              I ll just add by few cents on the ideas being kicked around It all sounds good, adding a PC interface to get programs into the ELF, large Flash memory as a
              Message 6 of 21 , Sep 10, 2003
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                I'll just add by few cents on the ideas being kicked around

                It all sounds good, adding a PC interface to get programs into the ELF,
                large Flash memory as a bulk filestore, all good ideas - but I feel some
                points should be included in the considerations.

                1) The group is acquiring a large software base of old and new programs for
                the 1802
                2) There are also several pieces of support or development software now
                available for the PC and other desktop platforms and may show up for the
                1802 platform as well.
                3) Historically, 1802 based systems were all different, Original ELF,
                homebrew ELF, Super ELF, ELF II even the RCA products. This trend is not
                stopping even now.
                4) Some members of the group prefer to have or use "original" hardware and
                designs (call us the purists if you must)

                Based on the large divergence between old and new 1802 projects, I would
                recommend that the group adopt a few practices:

                1) Settle on a few standard formats for distributing software (old and new)
                that are as close to universal as possible so as not to exclude owners of
                original hardware from benefiting by the availability of new, or resurrected
                code.

                2) Settle on a small number of standardized development environment for new
                code with defined conversion procedures so Flat ASCII files can be assembled
                to fit the unique hardware needs of the individual systems.

                3) Provide documentation with the software defining the I/O and the hardware
                configuration so both can be changed in the code in order to accommodate
                other physical environments.

                As one example:
                I have an original Quest Super ELF and a new build original ELF. I adapted
                the ELF to accommodate a memory expansion board that includes 16 K of RAM
                and 8 K of PROM (preserving the original look and feel of the ELF). I
                installed the Quest Super Monitor and the QUEST Tiny Basic in the PROM. I
                also added a MAX- 233 for RS-232 and am building up the cassette interface
                hardware found on the Super ELF. This configuration means I have a standard
                audio interface on both machines for mass storage and the read/write
                cassette software in PROM.

                Now, I can assemble code on my PC using PsudoSam18, save the binary file,
                post the ASCII source for others to adapt and use. I can obtain other
                source code and adapt it to my hardware needs.

                By using the ELF Tools, WAV -> BIN tool I can convert a binary file to a
                .WAV file, play the WAV into either machine, rip the wave into an MP3 and
                mail it around and I can burn either onto a CD for archival. I can even
                load the MP3's into an MP3 player and have a portable datastore. Best of
                all, it all still loads software into anyone's original hardware. It even
                supports the ELF II cassette format and can handle hardware designs that
                have a data inversion.

                Please remember, not everyone will be interested in new designs, new
                hardware, or new interfaces all the time.

                This group is a formidable team, with very diverse interests, that is a
                strength, and a liability.
                Leveraging that strength without falling prey to the effects of the
                liability will be key to remaining a team.
                Fragmentation is the pitfall to be avoided. I believe it was the key factor
                that limited the early 1802 users community in the '70s and, if not
                addressed, will soon have a similar result with this group.

                Just some points I feel should be considered...

                Thanks,
                Steve
                AA3NM

                -----Original Message-----
                From: Bill.Rowe [mailto:bill.rowe@...]
                Sent: Wednesday, September 10, 2003 10:17 AM
                To: cosmacelf@yahoogroups.com
                Subject: Re: [cosmacelf] Re: Improving my Elf?


                Josh: I don't have a working physical elf but the LPT port idea is cute.
                ----- Original Message -----
                From: "joshbensadon" <joshbensadon@...>
                To: <cosmacelf@yahoogroups.com>
                Sent: Tuesday, September 09, 2003 8:34 PM
                Subject: [cosmacelf] Re: Improving my Elf?


                > Hi Phil,
                >
                > Yes, those switches are a pain. Using hex keypad is a
                > pain too when you still need to manually reload.
                > Perhaps you might want to go with a tape save/load?
                > On my 2nd Elf, I added RS-232, so I may upload programs
                > in .hex format using any terminal program. I can share
                > that with you, if you want. It will need an Eprom and
                > an address latch with decoding.
                > The way I look at it...
                > 1. hex keypad needs some wiring, still need to reload
                > 2. tape interface needs little wiring, still need to toggle
                > in a save/restore program.
                > 3. RS-232 needs a lot of wiring, but lets you use any
                > standard terminal program
                >
                > Here's another idea...
                > 4. Parrallel connection. Uses little wiring.
                >
                > If you like the idea, I would love to be of some help.
                > Here's what I had in mind. Using the LPT port of your
                > computer to "enter" data into the Elf. First, we need
                > to share the input switches, so, add 10K resistors
                > between the switchs and the 4016's. Connect the 4016's
                > to pins 2-9 of the DB connector (data). Break the clock
                > line to the 4013 (pin 11) and put in a 3 pole jumper.
                > The jumper will allow either the input switch to clock
                > the data in, or connects the 4013 to pin 1 of the DB (Strobe).
                > Of course, connect pin 25 of the DB to ground.
                >
                > If you like the idea, I can write a program that will
                > "input a program" to the Elf via the LPT port.
                >
                > So... what do you think?
                >
                > Josh
                >
                >
                >
                >
                > ========================================================
                > Visit the COSMAC ELF website at http://www.cosmacelf.com,
                <http://www.cosmacelf.com,> or view the
                Wiki/FAQ at http://1802.bitting.com/ <http://1802.bitting.com/>
                >
                > To unsubscribe from this group, send an email to:
                > cosmacelf-unsubscribe@yahoogroups.com
                >
                >
                >
                > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                <http://docs.yahoo.com/info/terms/>
                >
                >



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                [Non-text portions of this message have been removed]
              • J.C. Wren
                This is why I d like to route the entire bus set through a FPGA, so that any attached devices can be mapped in and out of the system just be loading new FPGA
                Message 7 of 21 , Sep 10, 2003
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                  This is why I'd like to route the entire bus set through a FPGA, so that any
                  attached devices can be mapped in and out of the system just be loading new
                  FPGA code (on the fly. Perhaps the boot monitor comes up, and you select a
                  system map, for Elf, Super Elf, etc).

                  For me, the original systems are fun, but they're not much suited for
                  development. Flipping switches and having no reliable mass-store only go so
                  far. I wouldn't mind trying to do something useful, if I had a disk system.
                  I've done my time on cassettes, and nostalgia only goes so far.

                  Nothing beats a real 80x24 terminal and some mass-store for development.

                  --John


                  On Wednesday 10 September 2003 09:25 am, Gemeny, Steve wrote:
                  > I'll just add by few cents on the ideas being kicked around
                  >
                  > It all sounds good, adding a PC interface to get programs into the ELF,
                  > large Flash memory as a bulk filestore, all good ideas - but I feel some
                  > points should be included in the considerations.
                  >
                  > 1) The group is acquiring a large software base of old and new programs
                  > for the 1802
                  > 2) There are also several pieces of support or development software now
                  > available for the PC and other desktop platforms and may show up for the
                  > 1802 platform as well.
                  > 3) Historically, 1802 based systems were all different, Original ELF,
                  > homebrew ELF, Super ELF, ELF II even the RCA products. This trend is not
                  > stopping even now.
                  > 4) Some members of the group prefer to have or use "original" hardware and
                  > designs (call us the purists if you must)
                  >
                  > Based on the large divergence between old and new 1802 projects, I would
                  > recommend that the group adopt a few practices:
                  >
                  > 1) Settle on a few standard formats for distributing software (old and
                  > new) that are as close to universal as possible so as not to exclude owners
                  > of original hardware from benefiting by the availability of new, or
                  > resurrected code.
                  >
                  > 2) Settle on a small number of standardized development environment for
                  > new code with defined conversion procedures so Flat ASCII files can be
                  > assembled to fit the unique hardware needs of the individual systems.
                  >
                  > 3) Provide documentation with the software defining the I/O and the
                  > hardware configuration so both can be changed in the code in order to
                  > accommodate other physical environments.
                  >
                  > As one example:
                  > I have an original Quest Super ELF and a new build original ELF. I
                  > adapted the ELF to accommodate a memory expansion board that includes 16 K
                  > of RAM and 8 K of PROM (preserving the original look and feel of the ELF).
                  > I installed the Quest Super Monitor and the QUEST Tiny Basic in the PROM.
                  > I also added a MAX- 233 for RS-232 and am building up the cassette
                  > interface hardware found on the Super ELF. This configuration means I have
                  > a standard audio interface on both machines for mass storage and the
                  > read/write cassette software in PROM.
                  >
                  > Now, I can assemble code on my PC using PsudoSam18, save the binary file,
                  > post the ASCII source for others to adapt and use. I can obtain other
                  > source code and adapt it to my hardware needs.
                  >
                  > By using the ELF Tools, WAV -> BIN tool I can convert a binary file to a
                  > .WAV file, play the WAV into either machine, rip the wave into an MP3 and
                  > mail it around and I can burn either onto a CD for archival. I can even
                  > load the MP3's into an MP3 player and have a portable datastore. Best of
                  > all, it all still loads software into anyone's original hardware. It even
                  > supports the ELF II cassette format and can handle hardware designs that
                  > have a data inversion.
                  >
                  > Please remember, not everyone will be interested in new designs, new
                  > hardware, or new interfaces all the time.
                  >
                  > This group is a formidable team, with very diverse interests, that is a
                  > strength, and a liability.
                  > Leveraging that strength without falling prey to the effects of the
                  > liability will be key to remaining a team.
                  > Fragmentation is the pitfall to be avoided. I believe it was the key
                  > factor that limited the early 1802 users community in the '70s and, if not
                  > addressed, will soon have a similar result with this group.
                  >
                  > Just some points I feel should be considered...
                  >
                  > Thanks,
                  > Steve
                  > AA3NM

                  [snip]
                • Bill.Rowe
                  Josh: I don t have a working physical elf but the LPT port idea is cute. ... From: joshbensadon To:
                  Message 8 of 21 , Sep 10, 2003
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                    Josh: I don't have a working physical elf but the LPT port idea is cute.
                    ----- Original Message -----
                    From: "joshbensadon" <joshbensadon@...>
                    To: <cosmacelf@yahoogroups.com>
                    Sent: Tuesday, September 09, 2003 8:34 PM
                    Subject: [cosmacelf] Re: Improving my Elf?


                    > Hi Phil,
                    >
                    > Yes, those switches are a pain. Using hex keypad is a
                    > pain too when you still need to manually reload.
                    > Perhaps you might want to go with a tape save/load?
                    > On my 2nd Elf, I added RS-232, so I may upload programs
                    > in .hex format using any terminal program. I can share
                    > that with you, if you want. It will need an Eprom and
                    > an address latch with decoding.
                    > The way I look at it...
                    > 1. hex keypad needs some wiring, still need to reload
                    > 2. tape interface needs little wiring, still need to toggle
                    > in a save/restore program.
                    > 3. RS-232 needs a lot of wiring, but lets you use any
                    > standard terminal program
                    >
                    > Here's another idea...
                    > 4. Parrallel connection. Uses little wiring.
                    >
                    > If you like the idea, I would love to be of some help.
                    > Here's what I had in mind. Using the LPT port of your
                    > computer to "enter" data into the Elf. First, we need
                    > to share the input switches, so, add 10K resistors
                    > between the switchs and the 4016's. Connect the 4016's
                    > to pins 2-9 of the DB connector (data). Break the clock
                    > line to the 4013 (pin 11) and put in a 3 pole jumper.
                    > The jumper will allow either the input switch to clock
                    > the data in, or connects the 4013 to pin 1 of the DB (Strobe).
                    > Of course, connect pin 25 of the DB to ground.
                    >
                    > If you like the idea, I can write a program that will
                    > "input a program" to the Elf via the LPT port.
                    >
                    > So... what do you think?
                    >
                    > Josh
                    >
                    >
                    >
                    >
                    > ========================================================
                    > Visit the COSMAC ELF website at http://www.cosmacelf.com, or view the
                    Wiki/FAQ at http://1802.bitting.com/
                    >
                    > To unsubscribe from this group, send an email to:
                    > cosmacelf-unsubscribe@yahoogroups.com
                    >
                    >
                    >
                    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                    >
                    >
                  • joshbensadon
                    Steve, I had the very same dilemma when I was picking the parts to build my 2nd elf. I pulled out my old 2101 s and 2114 s, 4042 s, 4016 s and 4508. Then I
                    Message 9 of 21 , Sep 10, 2003
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                      Steve,

                      I had the very same dilemma when I was picking the
                      parts to build my 2nd elf. I pulled out my old
                      2101's and 2114's, 4042's, 4016's and 4508.

                      Then I thought about using a full 32k ram and 32k
                      eprom. I didn't know whether to build it 100%
                      original or to implement the "easy way". Considering
                      the space required to build it the original way
                      plus the time to wire so many chips. My goal perhaps
                      isn't the same as your's. I intend to just have fun
                      with the 1802. I don't plan on building a museum piece.
                      Also, I don't intend to use the 1802 in any of my
                      current day projects. So, I build my elf using modern
                      day short cuts. I replaced the 4042's, 4016's and 4508
                      with 74HC573's. I don't care about power consumption
                      as long as I don't over load the 7805. As for using
                      tape/wav, I want to try it, just for the fun of making
                      it work. Again, the word fun comes out.

                      I only want to have fun, and I'm sorry if this offends
                      anyone here, but in my opinion the 1802 had it's day
                      and is well written into the history books but as for
                      developing new applications for the 1802... it doesn't
                      make sense.

                      What you are asking is to make rules and standards for
                      a grandfather processor. The purpose of which is to
                      keep this group united. I believe our fondness of the
                      1802 is what brought us all here, and it will keep us
                      here.

                      I wonder if this group will disappear once our
                      generation has passed?

                      Josh
                    • Lee Hart
                      ... It s not hard. I d copy the VIP circuit, since software is already written for it. All you need is a CD4515, CD4051, and a 16-key keypad.
                      Message 10 of 21 , Sep 10, 2003
                      • 0 Attachment
                        Philip Pemberton wrote:
                        > I've just pulled my Cosmac Elf out of storage...
                        > Loading COSMAC code with the toggles is hard work. Is it worth
                        > trying to rig up a hex keypad for my Elf?

                        It's not hard. I'd copy the VIP circuit, since software is already
                        written for it. All you need is a CD4515, CD4051, and a 16-key keypad.

                        /EF3______________________________________________________/\/\___+5V
                        | | | | | | | | | | | | | | | | 22K
                        16 SPST |0 |1 |2 |3 |4 |5 |6 |7 |8 |9 |A |B |C |D |E |F
                        switches \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
                        | | | | | | | | | | | | | | | |
                        __|__|__|__|__|__|__|__|__|__|__|__|__|__|__|__|_
                        | 11 9 10 8 7 6 5 4 18 17 20 19 14 13 16 15 |
                        BUS0__|2 VDD 24|___+5v
                        BUS1__|3 CD4515 4-bit latch and 1-of-16 decoder |
                        BUS2__|21 INH 23|___
                        BUS3__|22 STROBE VSS 12|___|
                        |____________________1____________________________| |
                        _____________ | GND
                        +5v__|16 VDD | |
                        N0______|11 A ch0 13|_ |
                        N1______|10 B ch1 14|_ |
                        N2______|9 C ch2 15|____|__/\/\____
                        | ch3 12|_ 22k |
                        TPB_____|3 com ch4 1|_ GND
                        /MRD____|6 INH ch5 5|_
                        | ch6 2|_ CD4051
                        __|7 VEE ch7 4|_ 8-channel multiplexer
                        |__|8 VSS |
                        | |_____________|
                        GND

                        > I was also thinking of adding an upper address latch and EPROM
                        > socket... a second RAM may also be an option... Is there a
                        > defined standard for Elf interface connectors?

                        There are several (of course :-)

                        If you don't have any boards to plug into it anyway, I wouldn't worry
                        about which one is "best". I'd pick the one that is easiest for you to
                        get parts for and build.

                        RCA boards all used a double-sided edge connector, 22/22 pins on 0.156"
                        centers. Naturally, the VIP, Microtutor (their ELF), and Microboards
                        each had a different pinout. The TMSI BASYS boards used the same
                        connector, but with a different pinout. The SuperELF and Netronics ELF
                        used different connectors.

                        When I was at TMSI, we had a product called "Proteus". This was a metal
                        box with a BASYS/1 single-board 1802 computer in it. The top surface of
                        the box was a big E&L solderless breadboard socket (you know, the white
                        plastic blocks with a grid of holes on 0.1" centers). The 1802 was
                        unplugged from its socket, and plugged into the breadboard socket on
                        top. A pin header was soldered to the back of the breadboard socket, and
                        plugged into the 1802 socket on the BASYS/1 board inside the box. Thus,
                        what you had on top was a 'live' 1802 with all its RAM, ROM, power
                        supply, etc. inside the box. To add any desired circuit, you plugged the
                        chip in somewhere on the breadboard socket, and wired it to the 1802.
                        Thus, the 1802's pins were the 'expansion bus'.

                        This could be a very easy way to expand your ELF.
                        --
                        Lee A. Hart Ring the bells that still can ring
                        814 8th Ave. N. Forget your perfect offering
                        Sartell, MN 56377 USA There is a crack in everything
                        leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
                      • Lee Hart
                        ... This strikes me as using a hammer to put in screws. :-) The 1802 is EXTREMELY easy to load code into. You don t need no steenkin microcomputer to do it.
                        Message 11 of 21 , Sep 10, 2003
                        • 0 Attachment
                          schultdw wrote:
                          > I recently discovered this group and have been thinking about
                          > rebuilding my old ELF, or a reasonable facsimally thereof. But
                          > like you, I am not excited by the possibility of loading code
                          > with toggle switches. I remember doing that all too well.
                          >
                          > It occured to me that it might be possible to program a
                          > microcontroller (the PIC 16F876 springs to mind) as a
                          > bootloader. Using the serial port to download a program file
                          > from a host computer and then use the LOAD mode of the 1802
                          > to stuff the program into memory.

                          This strikes me as using a hammer to put in screws. :-)

                          The 1802 is EXTREMELY easy to load code into. You don't need no
                          steenkin' microcomputer to do it. It already *is* a microcomputer!

                          If the goal is to download from a PC, then you need to decide whether
                          you want to use the serial, parallel, or some other port (USB or
                          whatever).

                          If the PC has an RS-232 serial port, then the simplest route is to put a
                          'bit-banged' serial program on the 1802, and use the Q and EF4 lines to
                          transfer serial data. Personally, I think this is the least work and
                          most flexible. The software is already written (for example, my IDIOT
                          monitor). Burn it into an EPROM. The hardware is simple; 3 wires from
                          the PC serial port:

                          1802 pins PC RS-232 DB9
                          --------- 1k ------------
                          Q, pin 4________/\/\____________RD, pin 2

                          VCC, pin 16___
                          (+5v) |
                          >
                          22k >
                          >
                          /EF4, pin 21__| NPN
                          | 2N4401 4.7k
                          c \|________/\/\___TD, pin 3
                          e /| b _|_
                          | /_\ red LED
                          VSS, pin 20___|______|__________GND, pin 5

                          If you don't mind changing a few bytes in the IDIOT monitor to invert
                          the serial data received on EF4, then all you need is a series resistor
                          between /EF4 and TD. Can't get much simpler than that!

                          If you'd rather use the parallel port, and want to load parallel data,
                          then the 1802's DMA-IN and DMA-OUT features are the way to go. This will
                          take a lot more wires, and a few 4066 quad analog switch ICs. Basically,
                          the 8 data lines BUS0-7 go thru the analog switches to the parallel
                          port. You then use the 4 remaining output bits (STROBE, INIT, AUTO-FEED,
                          SELECT) for the ELF's LOAD, RUN, and IN switches, and the ENABLEs for
                          the analog switches. Also use the PC parallel port's status bits (BUSY,
                          ACK, SELECT-IN, PAPER-END, ERROR) to sense the 1802's N2, /MRD, and /MWR
                          lines.

                          Then, you have to write software for the PC to do what you manaully do
                          with the ELF switches; reset the 1802, set LOAD mode, set the data, and
                          strobe the IN switch. You can also have the PC watch the N2, /MRD and
                          /MWR lines to read/write bytes from the 1802 as if the were the ELF's
                          I/O port.
                          --
                          Lee A. Hart Ring the bells that still can ring
                          814 8th Ave. N. Forget your perfect offering
                          Sartell, MN 56377 USA There is a crack in everything
                          leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
                        • joshbensadon
                          Bill, ... Perhaps, but I look at it in terms of business. Does it make me money? or cost me money? Over all, it definitely did make me money, it taught me a
                          Message 12 of 21 , Sep 10, 2003
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                            Bill,

                            > a bit more to the 1802 than nostalgia.

                            Perhaps, but I look at it in terms of business. Does it
                            make me money? or cost me money? Over all, it definitely
                            did make me money, it taught me a lot about programming
                            and digital design. But I'm past that point now, way
                            past that point.

                            > get fun results with modest effort. Sum Fun is a hoot.

                            I can't argue with you there, I love my 1802! But I
                            don't see nassau (?) using 1802's in their next deep
                            space probe. Are they?

                            > I for one am in favour of some simple standards for I/O and code

                            But, to get back on topic about standards... perhaps
                            I am wrong? Maybe we could establish a standard for
                            all Elf's based upon the most popular or existing
                            standards? I have seen a couple of programs that
                            do not work on my elf because of I/O problems.
                            It's very disappointing!

                            So... where do we go from here? Shall we make a committee?
                            And who are we to be recognized as a standards committee?
                            I personally don't know enough about the various standards
                            currently in place for the numberous Elf's. So I must take
                            a back seat, and just applaud.

                            > If Babbage's difference engine had been easier to reproduce and
                            > documented I'd have one grinding out a game of life in the corner.

                            What??? you don't have a Babbage differencial engine! You
                            may borrow mine if you wish. :)
                            Is that Conway's Game of Life that you mentioned?
                            Funny you should mention it, I'm working on a version for
                            the ELF! Actually working on version 2, I'm concentrating
                            on speed. The first version does about 40 cycles per minute,
                            my 2nd version is up to 60 cpm. I'm still looking for ways to
                            make it go faster. I sure hope someone out there doesn't
                            already have a version that does 120 cpm! lol.


                            Josh.

                            PS. How you coming along with scanning the VIP diagrams?
                            I'd love to see them come online for everyone!
                            Is there a lot to scan? Perhaps you can mail me 1/2 the
                            material, so we can share the work?
                          • Bill.Rowe
                            ... Josh: I may be wrong of course but I think there is at least a bit more to the 1802 than nostalgia. The simplicity and transparency of the thing is
                            Message 13 of 21 , Sep 10, 2003
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                              Josh sed:
                              > What you are asking is to make rules and standards for
                              > a grandfather processor. The purpose of which is to
                              > keep this group united. I believe our fondness of the
                              > 1802 is what brought us all here, and it will keep us
                              > here. I wonder if this group will disappear once our
                              > generation has passed?

                              Josh: I may be wrong of course but I think there is at least a bit more to
                              the 1802 than nostalgia.
                              The simplicity and transparency of the thing is appealing and it has enough
                              capability to get fun results with modest effort. I think Sum Fun is a
                              hoot.

                              I for one am in favour of some simple standards for I/O and code sharing.
                              If Babbage's difference engine had been easier to reproduce and better
                              documented I'd have one grinding out a game of life in the corner.
                            • Michael Fogus
                              I m wondering which generation you speak of. I am 27 and was a toddler when the 1802 was king, but I love it for what it is. While there will never be a huge
                              Message 14 of 21 , Sep 11, 2003
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                                I'm wondering which generation you speak of. I am 27 and was a
                                toddler when the 1802 was king, but I love it for what it is. While
                                there will never be a huge wave of Elfs (Elves?) being assembled by a
                                large contingent of youths; I do feel that the 1802's intrinsic merit
                                will keep groups just like this running for years to come.

                                And what happens when technologies such as Paladium force a whole
                                generation of geeks to role their own systems? Methinks that the 1802
                                has a lot to teach those young'ins. ;)

                                -m



                                --- In cosmacelf@yahoogroups.com, "joshbensadon" <joshbensadon@y...>
                                wrote:

                                > I wonder if this group will disappear once our
                                > generation has passed?
                              • Lee Hart
                                ... What we use for educational purposes is often significantly different (simpler) than the real thing. Kids start out with plastic hammers, not real ones.
                                Message 15 of 21 , Sep 11, 2003
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                                  Michael Fogus wrote:
                                  > I'm wondering which generation you speak of. I am 27 and was a
                                  > toddler when the 1802 was king, but I love it for what it is. While
                                  > there will never be a huge wave of Elfs (Elves?) being assembled by a
                                  > large contingent of youths; I do feel that the 1802's intrinsic merit
                                  > will keep groups just like this running for years to come.
                                  >
                                  > And what happens when technologies such as Paladium force a whole
                                  > generation of geeks to role their own systems? Methinks that the 1802
                                  > has a lot to teach those young'ins. ;)

                                  What we use for educational purposes is often significantly different
                                  (simpler) than the 'real' thing. Kids start out with plastic hammers,
                                  not real ones. They build with Lego bricks, not real bricks.

                                  But most 'small' computers (PICs, Atmels, etc.) are not even remotely
                                  like 'big' ones. You can't really use them to learn about programming,
                                  adding memory, interfacing I/O devices, etc. Small micros have become so
                                  specialized that they are like modern Lego products; all custom-shaped
                                  parts that are only good for building the specific models pictured on
                                  the box.

                                  The 1802 is more like the original generic Lego bricks. Lumpy and crude,
                                  but you can build *anything* with them. They take more effort and things
                                  are less 'real' looking, but they maximize imagination and creativity.

                                  So, you never know. I've been debating with some friends about how you
                                  would build a kid's computer today. The obvious solution is something
                                  like a Nintendo or Lego Mindstorms; all pre-built, pre-packaged, and
                                  pre-programmed (and all secret mysteries as to how it works), but with
                                  some user interface that forces kids to use it the 'right' way that the
                                  oh-so-smart designers intended. Personally, I think this is the wrong
                                  approach.

                                  I'd rather a computer more like original Legos; so simple and obvious
                                  that the kids will figure out what they are good for and dream up ways
                                  to use them, without relying on adults to do all the thinking for them.
                                  Something like the old ELF computers!
                                  --
                                  Lee A. Hart Ring the bells that still can ring
                                  814 8th Ave. N. Forget your perfect offering
                                  Sartell, MN 56377 USA There is a crack in everything
                                  leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
                                • primo8880
                                  i m in this group since a few days... i m from swizzerland and i m 14 years old. i came across the elf only by chance. i love old computers (i really don t
                                  Message 16 of 21 , Sep 11, 2003
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                                    i'm in this group since a few days... i'm from swizzerland and i'm 14
                                    years old. i came across the elf only by chance. i love old computers
                                    (i really don't know where i have that from...) and so i saw on a
                                    picture in a book a elf. i immediatly searchd for it and i found this
                                    pages. i found quickly interest in the cosmac elf.
                                    i'm learning a lot about computers with an old microcomputer
                                    (microprofessor, ~1984). but now i find the elf is still more
                                    interesting than my mpf...
                                    so i think that old systems can be still today used for education.
                                    (ok, perhaps i'm exeption, the most of my friends can't understand
                                    what i find so interesting in old computers.) because they're symply
                                    to understand children can perhps learn a bit about the what happens
                                    really in their pc during they're gameing and so one.
                                    (sorry for my bad english...)

                                    --- In cosmacelf@yahoogroups.com, "Michael Fogus" <nospam@l...> wrote:
                                    > I'm wondering which generation you speak of. I am 27 and was a
                                    > toddler when the 1802 was king, but I love it for what it is. While
                                    > there will never be a huge wave of Elfs (Elves?) being assembled by
                                    a
                                    > large contingent of youths; I do feel that the 1802's intrinsic
                                    merit
                                    > will keep groups just like this running for years to come.
                                    >
                                    > And what happens when technologies such as Paladium force a whole
                                    > generation of geeks to role their own systems? Methinks that the
                                    1802
                                    > has a lot to teach those young'ins. ;)
                                    >
                                    > -m
                                    >
                                    >
                                    >
                                    > --- In cosmacelf@yahoogroups.com, "joshbensadon" <joshbensadon@y...>
                                    > wrote:
                                    >
                                    > > I wonder if this group will disappear once our
                                    > > generation has passed?
                                  • joshbensadon
                                    Thank you Michael! You sure put a smile on my face! I m only 37, now I don t feel that old or young! Josh ... a ... merit ... 1802
                                    Message 17 of 21 , Sep 11, 2003
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                                      Thank you Michael! You sure put a smile on my face!

                                      I'm only 37, now I don't feel that old or young!

                                      Josh

                                      --- In cosmacelf@yahoogroups.com, "Michael Fogus" <nospam@l...> wrote:
                                      > I'm wondering which generation you speak of. I am 27 and was a
                                      > toddler when the 1802 was king, but I love it for what it is. While
                                      > there will never be a huge wave of Elfs (Elves?) being assembled by
                                      a
                                      > large contingent of youths; I do feel that the 1802's intrinsic
                                      merit
                                      > will keep groups just like this running for years to come.
                                      >
                                      > And what happens when technologies such as Paladium force a whole
                                      > generation of geeks to role their own systems? Methinks that the
                                      1802
                                      > has a lot to teach those young'ins. ;)
                                      >
                                      > -m
                                      >
                                      >
                                      >
                                      > --- In cosmacelf@yahoogroups.com, "joshbensadon" <joshbensadon@y...>
                                      > wrote:
                                      >
                                      > > I wonder if this group will disappear once our
                                      > > generation has passed?
                                    • joshbensadon
                                      ... Lee, what are you talking about? I was 4 when I picked up my first real hammer and started pounding on some real bricks. hehe, lol! Josh
                                      Message 18 of 21 , Sep 11, 2003
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                                        > Kids start out with plastic hammers, not real ones.
                                        > They build with Lego bricks, not real bricks.

                                        Lee, what are you talking about?
                                        I was 4 when I picked up my first real hammer
                                        and started pounding on some real bricks.

                                        hehe, lol!

                                        Josh
                                      • joshbensadon
                                        Hi Primo, Welcome to the Elf Group. Your English is fine, just keep writting and people will ask you to repeat what is not understood. I m very supprised to
                                        Message 19 of 21 , Sep 11, 2003
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                                          Hi Primo,

                                          Welcome to the Elf Group. Your English is fine, just keep
                                          writting and people will ask you to repeat what is not
                                          understood.

                                          I'm very supprised to see a young 14 year old. Just a few
                                          days ago I was doubting the usefulness of the 1802 elf.
                                          You have taught this old dog (me) a new trick!

                                          Did you read the construction article in the Popular Electronics
                                          magazine? You can get it at www.cosmacelf.com
                                          It describes the 1802 beautifully. If you can build the
                                          real thing, it will be very satisfying!

                                          Josh


                                          --- In cosmacelf@yahoogroups.com, "primo8880" <r_wa@b...> wrote:
                                          > i'm in this group since a few days... i'm from swizzerland and i'm
                                          14
                                          > years old. i came across the elf only by chance. i love old
                                          computers
                                          > (i really don't know where i have that from...) and so i saw on a
                                          > picture in a book a elf. i immediatly searchd for it and i found
                                          this
                                          > pages. i found quickly interest in the cosmac elf.
                                          > i'm learning a lot about computers with an old microcomputer
                                          > (microprofessor, ~1984). but now i find the elf is still more
                                          > interesting than my mpf...
                                          > so i think that old systems can be still today used for education.
                                          > (ok, perhaps i'm exeption, the most of my friends can't understand
                                          > what i find so interesting in old computers.) because they're symply
                                          > to understand children can perhps learn a bit about the what happens
                                          > really in their pc during they're gameing and so one.
                                          > (sorry for my bad english...)
                                          >
                                        • primo8880
                                          yes, i alredy read the construction manual and i began refer to it. but for me it s a bit to complicated (already anyhow). but i will probably begin to try to
                                          Message 20 of 21 , Sep 17, 2003
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                                            yes, i alredy read the construction manual and i began refer to it.
                                            but for me it's a bit to complicated (already anyhow). but i will
                                            probably begin to try to construct one in about a year.

                                            --- In cosmacelf@yahoogroups.com, "joshbensadon" <joshbensadon@y...>
                                            wrote:
                                            > Hi Primo,
                                            >
                                            > Welcome to the Elf Group. Your English is fine, just keep
                                            > writting and people will ask you to repeat what is not
                                            > understood.
                                            >
                                            > I'm very supprised to see a young 14 year old. Just a few
                                            > days ago I was doubting the usefulness of the 1802 elf.
                                            > You have taught this old dog (me) a new trick!
                                            >
                                            > Did you read the construction article in the Popular Electronics
                                            > magazine? You can get it at www.cosmacelf.com
                                            > It describes the 1802 beautifully. If you can build the
                                            > real thing, it will be very satisfying!
                                            >
                                            > Josh
                                            >
                                            >
                                            > --- In cosmacelf@yahoogroups.com, "primo8880" <r_wa@b...> wrote:
                                            > > i'm in this group since a few days... i'm from swizzerland and
                                            i'm
                                            > 14
                                            > > years old. i came across the elf only by chance. i love old
                                            > computers
                                            > > (i really don't know where i have that from...) and so i saw on a
                                            > > picture in a book a elf. i immediatly searchd for it and i found
                                            > this
                                            > > pages. i found quickly interest in the cosmac elf.
                                            > > i'm learning a lot about computers with an old microcomputer
                                            > > (microprofessor, ~1984). but now i find the elf is still more
                                            > > interesting than my mpf...
                                            > > so i think that old systems can be still today used for
                                            education.
                                            > > (ok, perhaps i'm exeption, the most of my friends can't
                                            understand
                                            > > what i find so interesting in old computers.) because they're
                                            symply
                                            > > to understand children can perhps learn a bit about the what
                                            happens
                                            > > really in their pc during they're gameing and so one.
                                            > > (sorry for my bad english...)
                                            > >
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