Loading ...
Sorry, an error occurred while loading the content.
 

Free Running .pdf

Expand Messages
  • RickC
    http://f1.grp.yahoofs.com/v1/4Cq4Swugn-_chPC9lqsf7NSPI6sjVHUNzoCf2w4QM8JWo64Qe2-0M85l_S_OBOCctlC28PyRjq4tnl9CWueDNvQFaBTiMw/Other1802/1802%20Free%20Run.pdf I
    Message 1 of 11 , Apr 3, 2010
      http://f1.grp.yahoofs.com/v1/4Cq4Swugn-_chPC9lqsf7NSPI6sjVHUNzoCf2w4QM8JWo64Qe2-0M85l_S_OBOCctlC28PyRjq4tnl9CWueDNvQFaBTiMw/Other1802/1802%20Free%20Run.pdf

      I was looking through the files and I noticed what looks like a mistake. The LEDs either need to be reversed or they have to be tied to ground to work.

      Rick
    • Lee Hart
      ... Yes, I think you are correct. PS: The link didn t work for me. It took a while to find the schematic you were referring to. It s in the cosmacelf.com
      Message 2 of 11 , Apr 4, 2010
        RickC wrote:
        > http://f1.grp.yahoofs.com/v1/4Cq4Swugn-_chPC9lqsf7NSPI6sjVHUNzoCf2w4QM8JWo64Qe2-0M85l_S_OBOCctlC28PyRjq4tnl9CWueDNvQFaBTiMw/Other1802/1802%20Free%20Run.pdf
        >
        > I was looking through the files and I noticed what looks like a mistake. The LEDs either need to be reversed or they have to be tied to ground to work.

        Yes, I think you are correct.

        PS: The link didn't work for me. It took a while to find the schematic
        you were referring to. It's in the cosmacelf.com "files" section, click
        "other1802", and then "free run.pdf".
        --
        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
      • Mark Graybill
        Yup, either I got them backwards or I put in +5V for ground. I ll see if I can find the original file and fix it. Thanks for catching the error and pointing it
        Message 3 of 11 , Apr 4, 2010
          Yup, either I got them backwards or I put in +5V for ground. I'll see if I
          can find the original file and fix it. Thanks for catching the error and
          pointing it out.

          -Mark

          On Sat, Apr 3, 2010 at 11:41 PM, RickC <ricortes@...> wrote:

          >
          >
          >
          > http://f1.grp.yahoofs.com/v1/4Cq4Swugn-_chPC9lqsf7NSPI6sjVHUNzoCf2w4QM8JWo64Qe2-0M85l_S_OBOCctlC28PyRjq4tnl9CWueDNvQFaBTiMw/Other1802/1802%20Free%20Run.pdf
          >
          > I was looking through the files and I noticed what looks like a mistake.
          > The LEDs either need to be reversed or they have to be tied to ground to
          > work.
          >
          > Rick
          >
          >
          >


          [Non-text portions of this message have been removed]
        • Mark Graybill
          In fact, while I m at it I see other changes I can make to it to simplify things a lot. I ll incorporate those changes while I m at it. And I think I can make
          Message 4 of 11 , Apr 4, 2010
            In fact, while I'm at it I see other changes I can make to it to simplify
            things a lot. I'll incorporate those changes while I'm at it. And I think I
            can make a cleaner image now than I could with my tools on my home system
            back when I did this.

            -Mark

            On Sun, Apr 4, 2010 at 4:32 PM, Mark Graybill <saundby@...> wrote:

            > Yup, either I got them backwards or I put in +5V for ground. I'll see if I
            > can find the original file and fix it. Thanks for catching the error and
            > pointing it out.
            >
            > -Mark
            >
            >
            > On Sat, Apr 3, 2010 at 11:41 PM, RickC <ricortes@...> wrote:
            >
            >>
            >>
            >>
            >> http://f1.grp.yahoofs.com/v1/4Cq4Swugn-_chPC9lqsf7NSPI6sjVHUNzoCf2w4QM8JWo64Qe2-0M85l_S_OBOCctlC28PyRjq4tnl9CWueDNvQFaBTiMw/Other1802/1802%20Free%20Run.pdf
            >>
            >> I was looking through the files and I noticed what looks like a mistake.
            >> The LEDs either need to be reversed or they have to be tied to ground to
            >> work.
            >>
            >> Rick
            >>
            >>
            >>
            >
            >


            [Non-text portions of this message have been removed]
          • Rick Cortese
            It s a cute design, got me thinking. I lost my Super Elf when a company my son was working at tanked. I shouldn t have let him take it there for show and
            Message 5 of 11 , Apr 4, 2010
              It's a cute design, got me thinking.

              I lost my Super Elf when a company my son was working at tanked. I shouldn't have let him take it there for show and tell.

              I still have an 1802 CPU, I think it was one I got out of a printer buffer. I'll try your circuit to see if it is still alive. I was reading 6502 history and found out Woz based his Sweet 16 emulator on the 1802 because of the efficiency of the instruction set which got me here. I've forgotten everything about the instruction set except how tight you could code with it. I remember at the time it was considered one of the few processors that was so rich with registers that you could do something useful w/o RAM.

              I think I would like a minimal system. I Still have some other obsolete parts like a 6810. I'm thinking it would be cute to do something like use the standard upper 8 bits address latch but have its outputs tied in a resistor ladder DAC. To output $FF to the latch you would just load a register with anything in the $FFXX range and discard it. Ditto for everything down to $0000. Duty cycle wouldn't be 100% but it would be proportional and switch faster then you could hear. We'll see if I even get that far.


              ________________________________
              From: Mark Graybill <saundby@...>
              To: cosmacelf@yahoogroups.com
              Sent: Sun, April 4, 2010 4:37:16 PM
              Subject: Re: [cosmacelf] Free Running .pdf

              In fact, while I'm at it I see other changes I can make to it to simplify
              things a lot. I'll incorporate those changes while I'm at it. And I think I
              can make a cleaner image now than I could with my tools on my home system
              back when I did this.

              -Mark

              On Sun, Apr 4, 2010 at 4:32 PM, Mark Graybill <saundby@...> wrote:

              > Yup, either I got them backwards or I put in +5V for ground. I'll see if I
              > can find the original file and fix it. Thanks for catching the error and
              > pointing it out.
              >
              > -Mark
              >
              >
              > On Sat, Apr 3, 2010 at 11:41 PM, RickC <ricortes@...> wrote:
              >
              >>
              >>
              >>
              >> http://f1.grp.yahoofs.com/v1/4Cq4Swugn-_chPC9lqsf7NSPI6sjVHUNzoCf2w4QM8JWo64Qe2-0M85l_S_OBOCctlC28PyRjq4tnl9CWueDNvQFaBTiMw/Other1802/1802%20Free%20Run.pdf
              >>
              >> I was looking through the files and I noticed what looks like a mistake.
              >> The LEDs either need to be reversed or they have to be tied to ground to
              >> work.
              >>
              >> Rick
              >>
              >> 
              >>
              >
              >


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



              ------------------------------------

              ========================================================
              Visit the COSMAC ELF website at http://www.cosmacelf.comYahoo! Groups Links






              [Non-text portions of this message have been removed]
            • Lee Hart
              ... Are you looking at the 1802 free running file? It is just using the 1802 as an 8-bit counter. While it is certainly minimal, it also doesn t do much. You
              Message 6 of 11 , Apr 5, 2010
                Rick Cortese wrote:
                > It's a cute design, got me thinking.
                > I think I would like a minimal system.

                Are you looking at the "1802 free running" file? It is just using the
                1802 as an 8-bit counter. While it is certainly minimal, it also doesn't
                do much.

                You may want to look at some of my Membership card designs. These are
                intended as minimal Elf-type computers that really do run as computers.

                > I Still have some other obsolete parts like a 6810.

                That's a 128 byte RAM. It would work fine with an 1802 if 128 bytes is
                enough. Most Elf computers had at least 256 bytes.

                > I'm thinking it would be cute to do something like use the standard
                > upper 8 bits address latch but have its outputs tied in a resistor
                > ladder DAC. To output $FF to the latch you would just load a register
                > with anything in the $FFXX range and discard it.

                This would work, but not very well. The high address latch will get set
                on every single bus cycle. Some of these latch a real address, from the
                upper half of a register. But many of them will latch "nonsense" -- it's
                predictable, but not easy to account for in your software. If you are
                trying to make decent audio, it would likely punch it full of noise
                without extremely careful programming.

                It would be so much easier to use Q as your serial output to produce
                audio. You can set it high/low any time you like, with no side effects.

                --
                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
              • RickC
                ... At this stage I just want to see if the CPU works! IIRC the printer buffer I took it out of was a 64k for $5 and I just bought it for the RAM. I
                Message 7 of 11 , Apr 5, 2010
                  --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:
                  >
                  > Rick Cortese wrote:
                  > > It's a cute design, got me thinking.
                  > > I think I would like a minimal system.
                  >
                  > Are you looking at the "1802 free running" file? It is just using the
                  > 1802 as an 8-bit counter. While it is certainly minimal, it also doesn't
                  > do much.

                  At this stage I just want to see if the CPU works!<grin> IIRC the printer buffer I took it out of was a 64k for $5 and I just bought it for the RAM. I never tested it as a printer buffer.
                  >
                  > You may want to look at some of my Membership card designs. These are
                  > intended as minimal Elf-type computers that really do run as computers.

                  Yes and I want to thank you for doing the designs. They will give me a great start if I get the urge to go beyond something simple. I do have those 8k CMOS SRAMs I posted about in another thread, an EPROM burner, and dozens of EPROMs.
                  >
                  > > I Still have some other obsolete parts like a 6810.
                  >
                  > That's a 128 byte RAM. It would work fine with an 1802 if 128 bytes is
                  > enough. Most Elf computers had at least 256 bytes.
                  >

                  I hope I have the focus to stick with the process. Back in the day I was working as a chemist so expanded my Elf to 4k RAM and added an ADC chip so I could do data logging from a UV spectrometer.
                  > > I'm thinking it would be cute to do something like use the standard
                  > > upper 8 bits address latch but have its outputs tied in a resistor
                  > > ladder DAC. To output $FF to the latch you would just load a register
                  > > with anything in the $FFXX range and discard it.
                  >
                  > This would work, but not very well. The high address latch will get set
                  > on every single bus cycle. Some of these latch a real address, from the
                  > upper half of a register. But many of them will latch "nonsense" -- it's
                  > predictable, but not easy to account for in your software. If you are
                  > trying to make decent audio, it would likely punch it full of noise
                  > without extremely careful programming.

                  I'm hoping the noise will be above 10k Hz so I can just add an inductor to filter it. It may take some oddball techniques like mirroring the RAM through the entire memory map by not decoding the address space. Something like a tight loop at memory location $40 for instance. The high byte of the register will be put out on the address latch but is ignored by the program/RAM. Loading the high byte of the program counter with values from 0-$FF will output a proportional voltage<with noise> from the resistor ladder. The CPU will think everything including the delay loop is running from that particular page in memory so the value in the address latch should be fairly consistant.
                  >
                  > It would be so much easier to use Q as your serial output to produce
                  > audio. You can set it high/low any time you like, with no side effects.

                  Yeap, I remember some programs for my Elf in Quest Data where you just yelled into the speaker and it would record/playback your voice. I'll try to find some of sound effect programs I did from that period but it isn't too likely I will be able to retrieve them. I seem to recall writing a program that did attack/decay and frequency modification within it. I'd just give it a couple of seed numbers and I could get effects that sounded like video games of the era.

                  I'm not sure I want to revisit everything as it was. I'm still all over the map on where I may want to go with this. I just picked up a Atari CX85 keypad with a 74C923 keypad encoder chip but I'm not sure that is something I want to hook up. So many neat hacks have happened over the last 30 years. Not fixed but I think I would eventually like to just have a small boot EPROM that just sets up Q line and one of the flag lines like EF4 to do bit banging RS232 to a terminal and a RAM for loading programs.

                  Rick
                • Lee Hart
                  ... I suggest getting one of those white plastic solderless breadboarding sockets. Plug the 1802 into it. Wire the lines shown on that 1802 free running
                  Message 8 of 11 , Apr 5, 2010
                    RickC wrote:
                    > At this stage I just want to see if the CPU works!<grin>

                    I suggest getting one of those white plastic solderless breadboarding
                    sockets. Plug the 1802 into it. Wire the lines shown on that "1802 free
                    running" high through pullup resistors to +V (resistor value doesn't
                    matter).

                    Power supply: Anything from 3v to 6v is fine. Two AA batteries is
                    simple. Put a flashlight bulb in series as a current limiter. If you
                    short something or connect power backwards by mistake, it will light and
                    prevent any damage.

                    Oscillator: The simplest scheme is to connect a 1 megohm or greater
                    value resistor between 1802 pins 1 and 39. Then stick your finger or a
                    long piece of wire on pin 1 to pick up random 60 Hz noise. This is
                    enough to clock the 1802. :-)

                    Move the resistor on the DMA-OUT pin so it goes to ground instead of +v.
                    This tells the 1802 to start doing DMA-OUT (memory read) cycles. An LED
                    with a resistor in series will serve as a "logic probe". You can probe
                    the address pins, and will see them toggling high/low like an 8-bit counter.

                    Wire up your 6810 RAM. Now when you do these DMA-OUT cycles, they will
                    be reading random data from the RAM, which you can see on the data bus.

                    You can build up your Elf like this, one chip at a time, wiring and
                    testing each one as you go.
                    --
                    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
                  • Mark Graybill
                    OK, I ve replace the old erroneous file free-run with a new one. If anyone would like to do a sanity check on it for me, I d appreciate it. I believe I got
                    Message 9 of 11 , Apr 5, 2010
                      OK, I've replace the old erroneous file free-run with a new one.

                      If anyone would like to do a sanity check on it for me, I'd appreciate
                      it. I believe I got everything right this time, but my new digital
                      camera isn't sophisticated enough to generate a schematic from taking
                      a picture of my breadboard yet, so I've got a chance to introduce
                      plenty of errors when I manually draw up a schematic. ;)

                      What I use a free run circuit for is testing a CPU to make sure it's
                      basically functional. I also will usually build up a free run circuit
                      whenever I pick up a new processor as a way of familiarizing myself
                      with it's pinout, and any requirements to get it running such as
                      making sure all the /RESET, HOLD, INTR, /WAIT, /CLEAR, /DMA...etc
                      lines are held in the right state until I get to the point where I
                      build a circuit to start using them.

                      I'll usually build it up on a small solderless breadboard, and keep it
                      on hand. Then, when I start building up an actual computer circuit I
                      have a quick visual reference to use to make sure I'm going to the
                      correct pins, I'm holding things in the right state, and so on.

                      Plus, if kids come by to see your lab you have something you can
                      switch on for some quickie blinkenlights. =)

                      Mark Graybill
                      -----------------------------------------------------------------------------------------------------------------
                      http://saundby.com/
                      Electronics, Books, Video Games, etc.
                    • RickC
                      IMO: A single resistor on the power supply line to the LEDs would be a good idea just in case someone tries running it at 10V or so. One resistor would be
                      Message 10 of 11 , Apr 5, 2010
                        IMO: A single resistor on the power supply line to the LEDs would be a good idea just in case someone tries running it at 10V or so. One resistor would be enough. Some dimming when multiple LEDs are on may happen but it will add to the effect.

                        Rick

                        --- In cosmacelf@yahoogroups.com, Mark Graybill <saundby@...> wrote:
                        >
                        > OK, I've replace the old erroneous file free-run with a new one.
                        >
                        > If anyone would like to do a sanity check on it for me, I'd appreciate
                        > it. I believe I got everything right this time, but my new digital
                        > camera isn't sophisticated enough to generate a schematic from taking
                        > a picture of my breadboard yet, so I've got a chance to introduce
                        > plenty of errors when I manually draw up a schematic. ;)
                        >
                        > What I use a free run circuit for is testing a CPU to make sure it's
                        > basically functional. I also will usually build up a free run circuit
                        > whenever I pick up a new processor as a way of familiarizing myself
                        > with it's pinout, and any requirements to get it running such as
                        > making sure all the /RESET, HOLD, INTR, /WAIT, /CLEAR, /DMA...etc
                        > lines are held in the right state until I get to the point where I
                        > build a circuit to start using them.
                        >
                        > I'll usually build it up on a small solderless breadboard, and keep it
                        > on hand. Then, when I start building up an actual computer circuit I
                        > have a quick visual reference to use to make sure I'm going to the
                        > correct pins, I'm holding things in the right state, and so on.
                        >
                        > Plus, if kids come by to see your lab you have something you can
                        > switch on for some quickie blinkenlights. =)
                        >
                        > Mark Graybill
                        > -----------------------------------------------------------------------------------------------------------------
                        > http://saundby.com/
                        > Electronics, Books, Video Games, etc.
                        >
                      • Saundby
                        ... Thanks! What I ve done is specify a power supply range from 3.0 to 6.0VDC, and added a note about clock speeds/Vdd voltage. I also caught a missing dot
                        Message 11 of 11 , Apr 5, 2010
                          --- In cosmacelf@yahoogroups.com, "RickC" <ricortes@...> wrote:
                          >
                          > IMO: A single resistor on the power supply line to the LEDs would be a good idea just in case someone tries running it at 10V or so. One resistor would be enough. Some dimming when multiple LEDs are on may happen but it will add to the effect.
                          >
                          > Rick

                          Thanks!

                          What I've done is specify a power supply range from 3.0 to 6.0VDC, and added a note about clock speeds/Vdd voltage.

                          I also caught a missing "dot" at an intersection. While I had the document open I enlarged the text a bit. In hardcopy, it was pretty small, even for my new glasses. ;)

                          Anything else, let me know.

                          -Mark

                          >
                          > --- In cosmacelf@yahoogroups.com, Mark Graybill <saundby@> wrote:
                          > >
                          > > OK, I've replace the old erroneous file free-run with a new one.
                          > >
                          > > If anyone would like to do a sanity check on it for me, I'd appreciate
                          > > it. I believe I got everything right this time, but my new digital
                          > > camera isn't sophisticated enough to generate a schematic from taking
                          > > a picture of my breadboard yet, so I've got a chance to introduce
                          > > plenty of errors when I manually draw up a schematic. ;)
                          > >
                          > > What I use a free run circuit for is testing a CPU to make sure it's
                          > > basically functional. I also will usually build up a free run circuit
                          > > whenever I pick up a new processor as a way of familiarizing myself
                          > > with it's pinout, and any requirements to get it running such as
                          > > making sure all the /RESET, HOLD, INTR, /WAIT, /CLEAR, /DMA...etc
                          > > lines are held in the right state until I get to the point where I
                          > > build a circuit to start using them.
                          > >
                          > > I'll usually build it up on a small solderless breadboard, and keep it
                          > > on hand. Then, when I start building up an actual computer circuit I
                          > > have a quick visual reference to use to make sure I'm going to the
                          > > correct pins, I'm holding things in the right state, and so on.
                          > >
                          > > Plus, if kids come by to see your lab you have something you can
                          > > switch on for some quickie blinkenlights. =)
                          > >
                          > > Mark Graybill
                          > > -----------------------------------------------------------------------------------------------------------------
                          > > http://saundby.com/
                          > > Electronics, Books, Video Games, etc.
                          > >
                          >
                        Your message has been successfully submitted and would be delivered to recipients shortly.