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Re: [cosmacelf] Re: Is there any hardware junkies in this group

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  • Lee Hart
    ... Yes, you can add a latch, and trigger it at the right instant to capture (for example), the last high or low byte of the address, data bus, status of the
    Message 1 of 28 , Feb 1, 2011
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      Jim Hall wrote:
      > Could some kind of a crude latch grab the signal I am looking at and hold it,
      > send it to the LED? I am also wondering if that crude latch could access the
      > memory lines and see what is there as well? Forgive me if I am dense or not
      > asking the right question, I am trying to start over again after 25plus years of
      > working with a IBM and not thinking of what electronics do.

      Yes, you can add a latch, and trigger it at the right instant to capture
      (for example), the last high or low byte of the address, data bus,
      status of the control signals (read, write, instruction fetch, DMA
      cycle, etc.) But this tends to take a lot of parts, and requires many
      connections into the VIP logic. So, a lot of time is involved in hooking
      it all up.

      But, the 1802 is *so* simple that this sort of conservative approach
      used with other microprocessors is overkill. After you work with the
      1802 a bit, you will have "Aha!" moments when you realized there are
      much easier ways to do it.

      First, you can do it all in software. I'm fairly sure there are better
      monitor programs for the VIP that will single-step a program in
      software; The program to test is put in RAM. Let's say you want to
      execute the first byte of the program at 1000h. The monitor program:

      - looks at the instruction at 1000h to see if it is a 1, 2, or 3-byte
      instruction.
      - looks at the address of the *next* instruction after this one.
      - saves the byte at that location, and writes a "return to monitor"
      instruction in its place. This is called a "software breakpoint".
      - The monitor then executes the instruction at 1000h.
      - Just one instruction executes; then it returns to the monitor.
      - The monitor can save all the registers, display their contents,
      etc.
      - Repeat: The monitor can restore the original instruction at (say)
      1001h, write the software breakpoint into 1002h, and do it again.

      In this way, you can single step through a program one instruction at a
      time, and display the results after each step. All with no additional
      hardware at all!

      Or, if the problem is that the 1802 has hardware problems, you can add
      hardware single-stepping. RCA has the simple circuit for this in MPM-201
      (User manual for the COSMAC 1802 microprocessor).

      Or, since the 1802 is static (clock frequency can be zero), it is even
      simpler to add a circuit to over-ride the clock so it is controlled with
      a switch. All the signals then "freeze" right where they are, so you can
      easily view them with a simple LED+resistor.

      Does this make sense?
      --
      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
    • ted_rossin
      If you have about $10 you could build my cheap logic analyzer to get a good look at the 1802 signals:
      Message 2 of 28 , Feb 1, 2011
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        If you have about $10 you could build my cheap logic analyzer to get a good look at the 1802 signals:

        http://www.tedrossin.0sites.net/Electronics/Pic/Pic.html#LogicAnalyzer

        This will will run at up to 5M samples/second and also give you 5 analog channels to look at voltages if you want. I used this to help debug my Elf Clone:

        http://www.tedrossin.0sites.net/Electronics/RCA/RCA.html#ElfClone

        The only hitch is that you need to program the PIC microcontroller. The programmer costs about $35 but if you send me a part I can program it up for you. Just pay the return postage and I'd be happy to do it.

        --- In cosmacelf@yahoogroups.com, "sbirdasn" <sbirdasn@...> wrote:
        >
        >
        >
        > Speaking of which--
        >
        > I've been toying with the idea of building a software debugging tool using Parallax's Propeller CPU's. I initially thought that a real-time hardware ICE might be doable, but I've now come to the conclusion that it isn't possible at full 1802 speed with this chip (maybe 2nd gen *might* barely do it).
        >
        > However, I've recently kicked the idea around in my head that I *could* do a software trace bus sniffer at speeds up to about 2MHz (Pixie speed) with the Propeller chip.
        >
        > It would essentially be a poor man's logic analyzer with 1802 pod functionality. There would be a trace buffer, and some limited triggering to stop the sniffing. It would fake the register contents by emulating each instruction sniffed and update its own register file/D register in parallel with the real 1802 as the program runs.
        >
        > As long as there are no hardware faults or getting out of sync, the register contents should match. The Propeller would always have a video display that would show the present (emulated) contents of the registers (updated 60 times/second). When a trigger condition was met, then the register display updates would stop with the final contents after the trigger event. Then you could scroll through the trace memory to see what happened.
        >
        > Once the sniffing stopped, the trace display could get quite sophisticated.
        >
        > The total hardware to make such a gadget should be pretty minimal, even if you were careful and did full 5V-3.3V level conversion, the chip count should be less than 10.
        >
        > The down side to my little thought experiment is that I'm not a Propeller expert, so I figure there's a lot of development time to get something useful.
        >
        > Just a thought.
        >
        > Sbirdasn.
        >
      • Jim Hall
        Hello: Thanks for the great information on interfacing to the 1802, I will try some of the basic ideas as well as dust off some of my electronic thinking, and
        Message 3 of 28 , Feb 1, 2011
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          Hello:
          Thanks for the great information on interfacing to the 1802, I will try some of
          the basic ideas as well as dust off some of my electronic thinking, and hope I
          have a brief moment of AAHHHHHH when I find what I am loooking for.


          jim




          ________________________________
          From: Lee Hart <leeahart@...>
          To: cosmacelf@yahoogroups.com
          Sent: Tue, February 1, 2011 1:08:06 PM
          Subject: Re: [cosmacelf] Re: Is there any hardware junkies in this group

           
          Jim Hall wrote:
          > Could some kind of a crude latch grab the signal I am looking at and hold it,
          > send it to the LED? I am also wondering if that crude latch could access the
          > memory lines and see what is there as well? Forgive me if I am dense or not
          > asking the right question, I am trying to start over again after 25plus years
          >of
          > working with a IBM and not thinking of what electronics do.

          Yes, you can add a latch, and trigger it at the right instant to capture
          (for example), the last high or low byte of the address, data bus,
          status of the control signals (read, write, instruction fetch, DMA
          cycle, etc.) But this tends to take a lot of parts, and requires many
          connections into the VIP logic. So, a lot of time is involved in hooking
          it all up.

          But, the 1802 is *so* simple that this sort of conservative approach
          used with other microprocessors is overkill. After you work with the
          1802 a bit, you will have "Aha!" moments when you realized there are
          much easier ways to do it.

          First, you can do it all in software. I'm fairly sure there are better
          monitor programs for the VIP that will single-step a program in
          software; The program to test is put in RAM. Let's say you want to
          execute the first byte of the program at 1000h. The monitor program:

          - looks at the instruction at 1000h to see if it is a 1, 2, or 3-byte
          instruction.
          - looks at the address of the *next* instruction after this one.
          - saves the byte at that location, and writes a "return to monitor"
          instruction in its place. This is called a "software breakpoint".
          - The monitor then executes the instruction at 1000h.
          - Just one instruction executes; then it returns to the monitor.
          - The monitor can save all the registers, display their contents,
          etc.
          - Repeat: The monitor can restore the original instruction at (say)
          1001h, write the software breakpoint into 1002h, and do it again.

          In this way, you can single step through a program one instruction at a
          time, and display the results after each step. All with no additional
          hardware at all!

          Or, if the problem is that the 1802 has hardware problems, you can add
          hardware single-stepping. RCA has the simple circuit for this in MPM-201
          (User manual for the COSMAC 1802 microprocessor).

          Or, since the 1802 is static (clock frequency can be zero), it is even
          simpler to add a circuit to over-ride the clock so it is controlled with
          a switch. All the signals then "freeze" right where they are, so you can
          easily view them with a simple LED+resistor.

          Does this make sense?
          --
          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]
        • Jim Hall
          Hello: Im once again thankful for any kind of informaton on this great chip, I have been busy dusting off my electronic smarts and thinking of spending my time
          Message 4 of 28 , Feb 1, 2011
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            Hello:

            Im once again thankful for any kind of informaton on this great chip, I have
            been busy dusting off my electronic smarts and thinking of spending my time
            learning LOGIC and the basic's. Gee Spock would liket hat !


            jim




            ________________________________
            From: ted_rossin <ted_rossin@...>
            To: cosmacelf@yahoogroups.com
            Sent: Tue, February 1, 2011 3:54:20 PM
            Subject: [cosmacelf] Re: Is there any hardware junkies in this group

             


            If you have about $10 you could build my cheap logic analyzer to get a good look
            at the 1802 signals:

            http://www.tedrossin.0sites.net/Electronics/Pic/Pic.html#LogicAnalyzer

            This will will run at up to 5M samples/second and also give you 5 analog
            channels to look at voltages if you want. I used this to help debug my Elf
            Clone:

            http://www.tedrossin.0sites.net/Electronics/RCA/RCA.html#ElfClone

            The only hitch is that you need to program the PIC microcontroller. The
            programmer costs about $35 but if you send me a part I can program it up for
            you. Just pay the return postage and I'd be happy to do it.

            --- In cosmacelf@yahoogroups.com, "sbirdasn" <sbirdasn@...> wrote:
            >
            >
            >
            > Speaking of which--
            >
            > I've been toying with the idea of building a software debugging tool using
            >Parallax's Propeller CPU's. I initially thought that a real-time hardware ICE
            >might be doable, but I've now come to the conclusion that it isn't possible at
            >full 1802 speed with this chip (maybe 2nd gen *might* barely do it).
            >
            > However, I've recently kicked the idea around in my head that I *could* do a
            >software trace bus sniffer at speeds up to about 2MHz (Pixie speed) with the
            >Propeller chip.
            >
            > It would essentially be a poor man's logic analyzer with 1802 pod
            >functionality. There would be a trace buffer, and some limited triggering to
            >stop the sniffing. It would fake the register contents by emulating each
            >instruction sniffed and update its own register file/D register in parallel with
            >the real 1802 as the program runs.
            >
            > As long as there are no hardware faults or getting out of sync, the register
            >contents should match. The Propeller would always have a video display that
            >would show the present (emulated) contents of the registers (updated 60
            >times/second). When a trigger condition was met, then the register display
            >updates would stop with the final contents after the trigger event. Then you
            >could scroll through the trace memory to see what happened.
            >
            > Once the sniffing stopped, the trace display could get quite sophisticated.
            >
            > The total hardware to make such a gadget should be pretty minimal, even if you
            >were careful and did full 5V-3.3V level conversion, the chip count should be
            >less than 10.
            >
            > The down side to my little thought experiment is that I'm not a Propeller
            >expert, so I figure there's a lot of development time to get something useful.
            >
            > Just a thought.
            >
            > Sbirdasn.
            >







            [Non-text portions of this message have been removed]
          • Vince
            ... I was going to write 25 yrs, I ve got the perfect example until I realized my example is rapidly pushing 40 yrs old... Err I guess its not so much my
            Message 5 of 28 , Feb 1, 2011
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              --- In cosmacelf@yahoogroups.com, Jim Hall <jehall1442596@...> wrote:
              >
              > Hello:
              >
              > As I have been out of sink for more than 25yrs doing hardware projects, please
              > explain what a 'paralax propeller' does ?
              >
              >
              > jim

              I was going to write "25 yrs, I've got the perfect example" until I realized my example is rapidly pushing 40 yrs old... Err I guess its not so much my example getting old as it remains static in the late 60s/70s, but me whos gettin old...

              Anyway, you know what a CDC 6000 series PPU does? The whole "virtual ten processors" deal? Imagine all that in a single chip with some memory but without the attached supercomputer of course. And at least until very recently only programmable on a windows PC (so of little interest to me). A nifty, crazy, unique and lovable microcontroller architecture.

              Everything old is new again! Can't wait till they reinvent channels, VTAM, and bus -n- tag, thats gonna be fun.

              Vince
            • sbirdasn
              Though you may not have been on the forum before, we ve discussed this chip once or twice, as it s a chip now familiar to the hobbyist/hardware hacker
              Message 6 of 28 , Feb 1, 2011
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                Though you may not have been on the forum before, we've discussed this chip once or twice, as it's a chip now familiar to the hobbyist/hardware hacker community.

                Just google with keywords: Parallax Propeller

                I only throw out this chip since it has some really peculiar features that allow low chip count projects.

                I really don't *need* such a tool, as I have a Tektronix 338 32-channel x 256 sample logic analyzer, and a collection of oscilloscopes (analog & DSO) (and LP-1 logic probe) that are more than capable for 1802 development/debug.

                I ponder building Propeller projects like an 1802 sniffer with the idea that I might be able to have a tool that has features never dreamed of back in the old days, while not costing a mint to build, that others might enjoy making for their own use too.

                I think that having a "live" display of the 1802 register set would be the real key selling point for having such a gadget.

                I remember using a Z80 ICE (In-Circuit Emulator) back in the day that did show live display, but the output was only the address, data, and maybe one register at a time along with the status byte being monitored.

                An 1802 with its large register file would have been a real challenge for ICE live register display back when the 1802 was in current development.

                Also, the best of RCA's 1800 development tools are rare and fetch rather stiff prices on "fleabay", and still don't have the abilities I could put into my own little debugger project.

                Sbirdasn.
              • sbirdasn
                That little PIC logic analyzer is an interesting solution to sniffing a few lines. The main issue here is that for both the PIC and the Propeller MPU s, it
                Message 7 of 28 , Feb 1, 2011
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                  That little PIC logic analyzer is an interesting solution to sniffing a few lines.

                  The main issue here is that for both the PIC and the Propeller MPU's, it takes an additional development tool set for playing with the new devices, just to do the debugging/learning about the target 1802 system.

                  For someone just getting started again, that's a pretty messy solution.

                  I think that the original poster is best served by keeping things simple. The biggest problem is that the VIP is *not* designed for single-stepping and displaying the address/data bus live while the user walks through the program.

                  Yes, a VIP *could* be modified to single-step, but glomping on full address/data bus sniffing display LED's is a lot of wires for a computer that doesn't benefit much from it unless modified.

                  It would be easier to instead build a second computer as a basic ELF from scratch (wire-wrap since OP mentioned those skills) and add a bank of discrete LED's to see address/control lines as he sees the need for it.

                  Also, a few medium size solder-less breadboards would work for a temporary ELF project, and be reusable for other circuits once comfortable enough with 1802 code to go back to the VIP.

                  The basic ELF's Hex display with the built-in single step & load functionality goes a long way to understanding how the 1802 works without even an address display.

                  Yes, the Super Elf does have the address display option, but that adds at least 25-35% more wiring to the project if not more. And the power requirements jump up substantially as a result.

                  If the OP really wants live address/data display on his *VIP*, then he should buy a 22/44 pin edge card proto board large enough to mount the required latch/buffer/display chips on it, and plug it into the expansion bus of the VIP.

                  The decision to do hex vs discrete LED's will decide how much wiring is needed for the display board project, and the total cost.

                  Single-stepping modifications don't *have* to be made if branch/idle instructions are used to halt program execution during debugging.

                  Sbirdasn.
                • Lee Hart
                  ... Right. You can *simulate* it in software, by walking a breakpoint through a program in RAM, stopping after each instruction and displaying the address and
                  Message 8 of 28 , Feb 1, 2011
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                    sbirdasn wrote:
                    > I think that the original poster is best served by keeping things
                    > simple. The biggest problem is that the VIP is *not* designed for
                    > single-stepping and displaying the address/data bus live while the
                    > user walks through the program.

                    Right. You can *simulate* it in software, by walking a breakpoint
                    through a program in RAM, stopping after each instruction and displaying
                    the address and data on the video screen. (I know I've heard of such a
                    program for the VIP, but don't have it myself).

                    > Yes, a VIP *could* be modified to single-step

                    Yes; that's pretty easy. Basically, you defeat the crystal clock, and
                    use your own very slow clock. It could even be a debounced pushbutton.

                    > glomping on full address/data bus sniffing display LED's is a lot of
                    > wires for a computer that doesn't benefit much from it unless modified.

                    Absolutely. That's why I suggested just making some DIP clips that show
                    the state of the address and data buses when clipped onto the
                    appropriate chips. Address lines A0-A11 are already latched and available.

                    As built, the VIP wires 1802 /WAIT (pin 2) high. Add a switch or some
                    gate to pull this pin low, and the 1802 will freeze in place, so you can
                    examine all the lines with LEDs.

                    > If the OP really wants live address/data display on his *VIP*, then
                    > he should buy a 22/44 pin edge card proto board large enough to mount
                    > the required latch/buffer/display chips on it, and plug it into the
                    > expansion bus of the VIP.

                    That could work; but not all the signals needed are in the expansion
                    connectors.

                    --
                    Lee A. Hart | Ring the bells that still can ring
                    814 8th Ave N | Forget the perfect offering
                    Sartell MN 56377 | There is a crack in everything
                    leeahart earthlink.net | That's how the light gets in -- Leonard Cohen
                  • Jim Hall
                    Hello: Dont get me wrong in how simple the 1802 for the time, and how it came about, but if I was going to do something special to make the 1802 just a bit
                    Message 9 of 28 , Feb 1, 2011
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                      Hello:
                      Dont get me wrong in how simple the 1802 for the time, and how it came about,
                      but if I was going to do something special to make the 1802 just a bit better, I
                      would have a bread board area, spots for more memory and a place for more ROM. I
                      like the idea of having CHIP-8 in ROM, maybe a area for games and something
                      better than a hex keyboard.


                      Am I asking for too much here?

                      I am attaching a picture of something I wish I had,
                      jim




                      ________________________________
                      From: Lee Hart <leeahart@...>
                      To: cosmacelf@yahoogroups.com
                      Sent: Tue, February 1, 2011 11:56:10 PM
                      Subject: Re: [cosmacelf] Re: Is there any hardware junkies in this group

                       
                      sbirdasn wrote:
                      > I think that the original poster is best served by keeping things
                      > simple. The biggest problem is that the VIP is *not* designed for
                      > single-stepping and displaying the address/data bus live while the
                      > user walks through the program.

                      Right. You can *simulate* it in software, by walking a breakpoint
                      through a program in RAM, stopping after each instruction and displaying
                      the address and data on the video screen. (I know I've heard of such a
                      program for the VIP, but don't have it myself).

                      > Yes, a VIP *could* be modified to single-step

                      Yes; that's pretty easy. Basically, you defeat the crystal clock, and
                      use your own very slow clock. It could even be a debounced pushbutton.

                      > glomping on full address/data bus sniffing display LED's is a lot of
                      > wires for a computer that doesn't benefit much from it unless modified.

                      Absolutely. That's why I suggested just making some DIP clips that show
                      the state of the address and data buses when clipped onto the
                      appropriate chips. Address lines A0-A11 are already latched and available.

                      As built, the VIP wires 1802 /WAIT (pin 2) high. Add a switch or some
                      gate to pull this pin low, and the 1802 will freeze in place, so you can
                      examine all the lines with LEDs.

                      > If the OP really wants live address/data display on his *VIP*, then
                      > he should buy a 22/44 pin edge card proto board large enough to mount
                      > the required latch/buffer/display chips on it, and plug it into the
                      > expansion bus of the VIP.

                      That could work; but not all the signals needed are in the expansion
                      connectors.

                      --
                      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]
                    • Jim Hall
                      Hello: I dont want to beat this subject to death, but I like simplicity of things, but I like to have some kind smarts in what I am seeing. I will have to look
                      Message 10 of 28 , Feb 1, 2011
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                        Hello:

                        I dont want to beat this subject to death, but I like simplicity of things, but
                        I like to have some kind smarts in what I am seeing. I will have to look into
                        what could be done and maybe try it.


                        jim

                         



                        ________________________________
                        From: sbirdasn <sbirdasn@...>
                        To: cosmacelf@yahoogroups.com
                        Sent: Tue, February 1, 2011 10:52:21 PM
                        Subject: [cosmacelf] Re: Is there any hardware junkies in this group

                         


                        That little PIC logic analyzer is an interesting solution to sniffing a few
                        lines.

                        The main issue here is that for both the PIC and the Propeller MPU's, it takes
                        an additional development tool set for playing with the new devices, just to do
                        the debugging/learning about the target 1802 system.

                        For someone just getting started again, that's a pretty messy solution.

                        I think that the original poster is best served by keeping things simple. The
                        biggest problem is that the VIP is *not* designed for single-stepping and
                        displaying the address/data bus live while the user walks through the program.

                        Yes, a VIP *could* be modified to single-step, but glomping on full address/data
                        bus sniffing display LED's is a lot of wires for a computer that doesn't benefit
                        much from it unless modified.

                        It would be easier to instead build a second computer as a basic ELF from
                        scratch (wire-wrap since OP mentioned those skills) and add a bank of discrete
                        LED's to see address/control lines as he sees the need for it.

                        Also, a few medium size solder-less breadboards would work for a temporary ELF
                        project, and be reusable for other circuits once comfortable enough with 1802
                        code to go back to the VIP.

                        The basic ELF's Hex display with the built-in single step & load functionality
                        goes a long way to understanding how the 1802 works without even an address
                        display.

                        Yes, the Super Elf does have the address display option, but that adds at least
                        25-35% more wiring to the project if not more. And the power requirements jump
                        up substantially as a result.

                        If the OP really wants live address/data display on his *VIP*, then he should
                        buy a 22/44 pin edge card proto board large enough to mount the required
                        latch/buffer/display chips on it, and plug it into the expansion bus of the VIP.

                        The decision to do hex vs discrete LED's will decide how much wiring is needed
                        for the display board project, and the total cost.

                        Single-stepping modifications don't *have* to be made if branch/idle
                        instructions are used to halt program execution during debugging.

                        Sbirdasn.







                        [Non-text portions of this message have been removed]
                      • Jim Hall
                        Hello: Sorry I am the new guy on the block, and just dusted of my VIP and started reading the VIPER s that I have found after all the years of sitting there
                        Message 11 of 28 , Feb 1, 2011
                        • 0 Attachment
                          Hello:

                          Sorry I am the new guy on the block, and just dusted of my VIP and started
                          reading the VIPER's that I have found after all the years of sitting there
                          gathering dust. I will have to get back to you and see if I can get the supplies
                          I need. I like wire wrapping and bread boards as well, and have time to spend on
                          something that will help me pass the time, being retired for only a few months.

                          jim




                          ________________________________
                          From: Vince <vince@...>
                          To: cosmacelf@yahoogroups.com
                          Sent: Tue, February 1, 2011 7:43:59 PM
                          Subject: [cosmacelf] Re: Is there any hardware junkies in this group

                           
                          --- In cosmacelf@yahoogroups.com, Jim Hall <jehall1442596@...> wrote:
                          >
                          > Hello:
                          >
                          > As I have been out of sink for more than 25yrs doing hardware projects, please

                          > explain what a 'paralax propeller' does ?
                          >
                          >
                          > jim

                          I was going to write "25 yrs, I've got the perfect example" until I realized my
                          example is rapidly pushing 40 yrs old... Err I guess its not so much my example
                          getting old as it remains static in the late 60s/70s, but me whos gettin old...

                          Anyway, you know what a CDC 6000 series PPU does? The whole "virtual ten
                          processors" deal? Imagine all that in a single chip with some memory but without
                          the attached supercomputer of course. And at least until very recently only
                          programmable on a windows PC (so of little interest to me). A nifty, crazy,
                          unique and lovable microcontroller architecture.

                          Everything old is new again! Can't wait till they reinvent channels, VTAM, and
                          bus -n- tag, thats gonna be fun.

                          Vince







                          [Non-text portions of this message have been removed]
                        • awasson2001
                          Unfortunately the attachment didn t make it through (at least not to me). Maybe upload it to the photos or files section. Just to satisfy intellectual
                          Message 12 of 28 , Feb 1, 2011
                          • 0 Attachment
                            Unfortunately the attachment didn't make it through (at least not to me). Maybe upload it to the photos or files section.

                            Just to satisfy intellectual curiosity I'm keen to try out some clips with LED's that Lee was describing but I'd really like to see something along the lines of what Sbirdasn was describing with hardware and a row of LEDs to select and display the register contents. That would be cool in a blinken lights kind of way. Not that it would be necessary but it's always fun to watch blinking LEDs on our old hardware.

                            Andrew

                            --- In cosmacelf@yahoogroups.com, Jim Hall <jehall1442596@...> wrote:
                            >
                            > Hello:
                            > Dont get me wrong in how simple the 1802 for the time, and how it came about,
                            > but if I was going to do something special to make the 1802 just a bit better, I
                            > would have a bread board area, spots for more memory and a place for more ROM. I
                            > like the idea of having CHIP-8 in ROM, maybe a area for games and something
                            > better than a hex keyboard.
                            >
                            >
                            > Am I asking for too much here?
                            >
                            > I am attaching a picture of something I wish I had,
                            > jim
                            >
                            >
                            >
                            >
                            > ________________________________
                            > From: Lee Hart <leeahart@...>
                            > To: cosmacelf@yahoogroups.com
                            > Sent: Tue, February 1, 2011 11:56:10 PM
                            > Subject: Re: [cosmacelf] Re: Is there any hardware junkies in this group
                            >
                            >  
                            > sbirdasn wrote:
                            > > I think that the original poster is best served by keeping things
                            > > simple. The biggest problem is that the VIP is *not* designed for
                            > > single-stepping and displaying the address/data bus live while the
                            > > user walks through the program.
                            >
                            > Right. You can *simulate* it in software, by walking a breakpoint
                            > through a program in RAM, stopping after each instruction and displaying
                            > the address and data on the video screen. (I know I've heard of such a
                            > program for the VIP, but don't have it myself).
                            >
                            > > Yes, a VIP *could* be modified to single-step
                            >
                            > Yes; that's pretty easy. Basically, you defeat the crystal clock, and
                            > use your own very slow clock. It could even be a debounced pushbutton.
                            >
                            > > glomping on full address/data bus sniffing display LED's is a lot of
                            > > wires for a computer that doesn't benefit much from it unless modified.
                            >
                            > Absolutely. That's why I suggested just making some DIP clips that show
                            > the state of the address and data buses when clipped onto the
                            > appropriate chips. Address lines A0-A11 are already latched and available.
                            >
                            > As built, the VIP wires 1802 /WAIT (pin 2) high. Add a switch or some
                            > gate to pull this pin low, and the 1802 will freeze in place, so you can
                            > examine all the lines with LEDs.
                            >
                            > > If the OP really wants live address/data display on his *VIP*, then
                            > > he should buy a 22/44 pin edge card proto board large enough to mount
                            > > the required latch/buffer/display chips on it, and plug it into the
                            > > expansion bus of the VIP.
                            >
                            > That could work; but not all the signals needed are in the expansion
                            > connectors.
                            >
                            > --
                            > 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]
                            >
                          • Lee Hart
                            ... Not to me either. I don t think this list accepts attachments (too high a risk of malware). ... Well, here s how I did it on my very first ELF. Everything
                            Message 13 of 28 , Feb 2, 2011
                            • 0 Attachment
                              awasson2001 wrote:
                              > Unfortunately the attachment didn't make it through (at least not to
                              > me). Maybe upload it to the photos or files section.

                              Not to me either. I don't think this list accepts attachments (too high
                              a risk of malware).

                              > Just to satisfy intellectual curiosity I'm keen to try out some clips
                              > with LED's that Lee was describing but I'd really like to see
                              > something along the lines of what Sbirdasn was describing with
                              > hardware and a row of LEDs to select and display the register
                              > contents. That would be cool in a blinken lights kind of way. Not
                              > that it would be necessary but it's always fun to watch blinking LEDs
                              > on our old hardware.

                              Well, here's how I did it on my very first ELF.

                              Everything was on separate 4.5" x 6.5" cards; CPU, RAM, ROM, I/O etc.
                              Each had a 44-pin edge connector. They all plugged into a bus that
                              connected all pin 1-s together, all pin 2's etc.

                              One of the cards was a front panel. It had the usual toggle switches and
                              LEDs for control and data. The data was captured by two 4042 quad
                              latches and displayed by 8 LEDs. The address was captured by four 4042
                              4-bit latches, and displayed by 16 LEDs. The high byte address was
                              latched by TPA, and the low byte by TPB. There were also 4049 buffers
                              driving LEDs for the various control lines.

                              The crystal clock was gated by a 4011 so it could be stopped. While
                              stopped, a bounceless pushbutton could pulse the clock low to single
                              step one clock pulse at a time (took 8 button pushes for each bus
                              cycle). Like this (view with a fixed width font like Courier):

                              +5v _ crystal oscillator (crystal,
                              | ____|| ||____ resistor, 2 capacitors)
                              > | ||_|| |
                              10k > | _____ |
                              Run __ > |__|U1A \ | _____
                              S1 \__|_____|4011 )O__|__|U1B \
                              Stop __ | |_____/ __|4011B )O____1802 clock
                              | | +5v___ | |_____/
                              gnd | STEP S2 \___|
                              | gnd___ _|_
                              D1__|/|__| ___ 0.01uF
                              |\| | |
                              ... | gnd
                              Dn__|/|__|
                              |\|

                              S1 is the Run/Stop toggle switch. When up (Run), the 10k resistor pulls
                              the lower input of U1A high, and the crystal oscillator runs. When S1 is
                              down (Stop), it grounds the input of U1A, forcing its output high and
                              the oscillator is stopped.

                              S2 is the single-step pushbutton. It is normally high, letting the
                              oscillator pass through U1B to the 1802. When you push S2, it grounds
                              the lower input of U1B, forcing its output high. You normally stop the
                              oscillator with S1 so the 1802 clock is low; then pressing S2 pulses the
                              1802 clock high.

                              The 0.01uf capacitor on C2 makes it a "bounceless" pushbutton. When the
                              switch slowly moves from up to down, its contacts "bounce" open and
                              closed many times. The capacitor holds the state of the last contact to
                              have touched (up or down) despite the bouncing, until the switch has
                              moved enough to actually touch the opposite contact. This instantly
                              charges or discharges the capacitor, holding the new level until the
                              switch stops bouncing.

                              The diodes D1-Dn are a crude logic analyzer. They form a simple OR gate,
                              where the cathodes of all the diodes must be high to Run. If you want to
                              stop at the first write cycle, connect a diode cathode to MWR. The 4042
                              quad latch has both true and inverted outputs, which means you can stop
                              on any high or low on any address or data line as well.
                              --
                              Lee A. Hart | Ring the bells that still can ring
                              814 8th Ave N | Forget the perfect offering
                              Sartell MN 56377 | There is a crack in everything
                              leeahart earthlink.net | That's how the light gets in -- Leonard Cohen
                            • Jim Hall
                              Hello: Sorry that I dont know how to upload to the file area, please advise me how , so I can upload the 1802 board I found that I like most. jim
                              Message 14 of 28 , Feb 2, 2011
                              • 0 Attachment
                                Hello:

                                Sorry that I dont know how to upload to the file area, please advise me how , so
                                I can upload the 1802 board I found that I like most.
                                jim




                                ________________________________
                                From: Lee Hart <leeahart@...>
                                To: cosmacelf@yahoogroups.com
                                Sent: Wed, February 2, 2011 1:18:21 PM
                                Subject: Re: [cosmacelf] Re: Is there any hardware junkies in this group

                                 
                                awasson2001 wrote:
                                > Unfortunately the attachment didn't make it through (at least not to
                                > me). Maybe upload it to the photos or files section.

                                Not to me either. I don't think this list accepts attachments (too high
                                a risk of malware).

                                > Just to satisfy intellectual curiosity I'm keen to try out some clips
                                > with LED's that Lee was describing but I'd really like to see
                                > something along the lines of what Sbirdasn was describing with
                                > hardware and a row of LEDs to select and display the register
                                > contents. That would be cool in a blinken lights kind of way. Not
                                > that it would be necessary but it's always fun to watch blinking LEDs
                                > on our old hardware.

                                Well, here's how I did it on my very first ELF.

                                Everything was on separate 4.5" x 6.5" cards; CPU, RAM, ROM, I/O etc.
                                Each had a 44-pin edge connector. They all plugged into a bus that
                                connected all pin 1-s together, all pin 2's etc.

                                One of the cards was a front panel. It had the usual toggle switches and
                                LEDs for control and data. The data was captured by two 4042 quad
                                latches and displayed by 8 LEDs. The address was captured by four 4042
                                4-bit latches, and displayed by 16 LEDs. The high byte address was
                                latched by TPA, and the low byte by TPB. There were also 4049 buffers
                                driving LEDs for the various control lines.

                                The crystal clock was gated by a 4011 so it could be stopped. While
                                stopped, a bounceless pushbutton could pulse the clock low to single
                                step one clock pulse at a time (took 8 button pushes for each bus
                                cycle). Like this (view with a fixed width font like Courier):

                                +5v _ crystal oscillator (crystal,
                                | ____|| ||____ resistor, 2 capacitors)
                                > | ||_|| |
                                10k > | _____ |
                                Run __ > |__|U1A \ | _____
                                S1 \__|_____|4011 )O__|__|U1B \
                                Stop __ | |_____/ __|4011B )O____1802 clock
                                | | +5v___ | |_____/
                                gnd | STEP S2 \___|
                                | gnd___ _|_
                                D1__|/|__| ___ 0.01uF
                                |\| | |
                                ... | gnd
                                Dn__|/|__|
                                |\|

                                S1 is the Run/Stop toggle switch. When up (Run), the 10k resistor pulls
                                the lower input of U1A high, and the crystal oscillator runs. When S1 is
                                down (Stop), it grounds the input of U1A, forcing its output high and
                                the oscillator is stopped.

                                S2 is the single-step pushbutton. It is normally high, letting the
                                oscillator pass through U1B to the 1802. When you push S2, it grounds
                                the lower input of U1B, forcing its output high. You normally stop the
                                oscillator with S1 so the 1802 clock is low; then pressing S2 pulses the
                                1802 clock high.

                                The 0.01uf capacitor on C2 makes it a "bounceless" pushbutton. When the
                                switch slowly moves from up to down, its contacts "bounce" open and
                                closed many times. The capacitor holds the state of the last contact to
                                have touched (up or down) despite the bouncing, until the switch has
                                moved enough to actually touch the opposite contact. This instantly
                                charges or discharges the capacitor, holding the new level until the
                                switch stops bouncing.

                                The diodes D1-Dn are a crude logic analyzer. They form a simple OR gate,
                                where the cathodes of all the diodes must be high to Run. If you want to
                                stop at the first write cycle, connect a diode cathode to MWR. The 4042
                                quad latch has both true and inverted outputs, which means you can stop
                                on any high or low on any address or data line as well.
                                --
                                Lee A. Hart | Ring the bells that still can ring
                                814 8th Ave N | Forget the perfect offering
                                Sartell MN 56377 | There is a crack in everything
                                leeahart earthlink.net | That's how the light gets in -- Leonard Cohen






                                [Non-text portions of this message have been removed]
                              • ted_rossin
                                That is the reason I offered to program the chip and send it to the orignal poster. No need to learn the Microchip tool set. Just wire it up on a solderless
                                Message 15 of 28 , Feb 2, 2011
                                • 0 Attachment
                                  That is the reason I offered to program the chip and send it to the orignal poster. No need to learn the Microchip tool set. Just wire it up on a solderless breadboard and away you go. You can build it in under 10 minutes.

                                  --- In cosmacelf@yahoogroups.com, "sbirdasn" <sbirdasn@...> wrote:
                                  >
                                  >
                                  >
                                  > That little PIC logic analyzer is an interesting solution to sniffing a few lines.
                                  >
                                  > The main issue here is that for both the PIC and the Propeller MPU's, it takes an additional development tool set for playing with the new devices, just to do the debugging/learning about the target 1802 system.
                                  >
                                  > For someone just getting started again, that's a pretty messy solution.
                                  >

                                  ...

                                  \> Sbirdasn.
                                  >
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