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Request for comment: Modifed circuit of RL01/RL02 disc emu I/F (mod from pdp11gy.com)

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    #1

    Request for comment: Modifed circuit of RL01/RL02 disc emu I/F (mod from pdp11gy.com)

    Hi All,
    I’m very interested in the RL01/RL02 emulator by PDP11GY and trying to make it for my LSI-11/23. I'm drawing the complete circuit diagram to design PCB (maybe 4-layers, 160x100 size).

    I made modifications to the original circuit by Reinard:
    - Added the 5V tolerant 3.3V logic (SN74LVC16244) for level conversion of input signals
    - Added on-board terminator.
    - Pin assign identical to RLV11 connector to use simple cable instead of DEC’s cable.
    - Use B version of 75107.

    I would appreciate it if you could review and give comments for the uploaded circuit diagram in the PDF format.

    Download link is: https://www.dropbox.com/s/nw9audxf41...41011.PDF?dl=0
    Tags: lsi-11, pdp-11, rl01, rl02, rl02_simulator
    #2
    Your Terminator is incorrect.
    All resistors must be connected to Ground.
    See my Schematic from the original Terminator.
    RL01_RL02_Terminator.jpg

    Comment

      #3
      Thanks for comment and schematic diagram.
      I'll fix terminator in the next revision.

      Comment

        #4
        Now I have to send the current project status earlier.
        First of all, in my project, the "DE0 Nano" period of time is over and it is replaced by a BeMicro CV board.
        http://components-asiapac.arrow.com/...V_A2_v1.04.pdf
        In the appendix, you can see the prototype.
        The Hardware is up and running and most of the Software is alread ported to the Quartus Version 13.1 environment.
        The plan also is to develop a PCB board for the new generation of the RL02 simulator.
        The BeMicro CV baord has many advantages:
        More Memory: 128 MB : We can hold 4 RL02 Drives in Memory !
        MICRO SD-Card ......... and costs almost only half !!
        I only can recommend to put not more effort into the GB0-Nano based RL02 swimulator.
        I'm giving you a new update when the project is finished.
        Regards, Reinhard

        IMG_1879.jpg

        Comment

          #5
          Reinhard,

          The new hardware design is very nice. Will you at least keep the .DEC file format the same?

          Lou

          Comment

            #6
            Thanks for informing the current status of the project. It's awesome!
            I have closed my project with DE0 Nano. I'm waiting for finishing your new project.

            Anyway, is the number of drives configurable? That is, I want to use
            - four simulator drives
            - one real RL02 drive and one simulator drives
            - one real RL02 drive and three simulator drives

            Are latter two configurations possible with new hardware?

            Regards, coredump

            Comment

              #7
              I am giving this a lot of thought. Having the ability to use SD cards to backup and share software would be a blast. Just looking at what it would cost for the DE0-Nano Development board and the other components to bring this all together and have a couple questions.
              First, why have the 74LS245 buffer that in turn is followed by a 74LVC16244 level converter? Do you need the first buffer for anything like a data inversion? Looks to me like it’s just a buffer left over from the original design and the function of the level converter will be doing the same thing?
              Second, I have looked and all I can find the 74LVC16244 in is surface mount. I am thinking of building all this in a large case that would rack mount between my processor and RL drives and am planning on using all wire wrap being that’s how old guys like me do things. The 74LVC8T245 level conversion modules look like they may be easy to work with although I would need two but they appear easy to deal with, I did not see anything with 74LVC16244 that looks friendly. Anyone aware of a different or dip style package level translator?
              And last but not least, I know the files on the SD card will be in a FAT32 structure but what would the files look like on a windows system? Can you easily deal with ripping them from the card and do things like email them or use a text editor to look at or change them? What type extensions will they have? Anybody gat a screen shot of what a RL drives contents transferred to a SD card look like?

              Comment

                #8
                First, I will use SMDs simply because I have no experience of wire wrapping. Another reason is to reduce PCB size.
                Second, I am afraid of overshooting problem (and crashing FPGA), so I added 74LVC16244 for level conversion between 5V section and 3.3V section. A dual-supply translator is, of course, another candidate for this purpose.

                Comment

                  #9
                  Originally posted by coredump View Post
                  First, I will use SMDs simply because I have no experience of wire wrapping.
                  Also, wire-wrap SD card sockets are difficult to find.

                  Comment

                    #10
                    I am planning on chopping up an old multi card reader to get the SD Card socket assembly, may be difficult but think I can manage to solder wire to the traces on the socket. The above mentioned BeMicro CV board sounds like it has a Micro SD already built in and that can be an advantage, although looks like everything is already done for using the DE0-Nano Development board. After all I am already twenty eight generations behind running RL drives in the first place so who cares if I don’t have the latest and best SD Card RL simulator?

                    Comment

                      #11
                      I made my own SD card to wire wrap adapter. See here: http://www.vintage-computer.com/vcfo...chmentid=12237

                      I didn't use it for wire wrap, but plugged it into a header socket. It is annoying that the SDcard pins are not on 0.1" centers. What were they thinking? I made a little adapter board so that initially I could plug the SDcard slot directly into my wirewrapped main board, but extend it on a ribbon cable and mount it on the front panel later. Here it is plugged in directly: http://www.vintage-computer.com/vcfo...chmentid=12234 and here you can see the extension ribbon to the front panel http://www.vintage-computer.com/vcfo...chmentid=14133.

                      The Be Micro CV does have an on board microSD socket. Those microSD cards are annoyingly small. I did see someone have the good idea of soldering leads onto the pads of a microSD to full size SD adapter instead of buying a proper socket.

                      Coredump, I apologize for not responding to your earlier post, but have been swamped with other stuff (and will be for one more week.) I built Reinhard's old design and also did use an LVC244 for level conversion. The voltage dividers worked lousy for me. I had pulse shape distortion and crosstalk from the drive bus clock.

                      It does work impressively well and is really convenient. I hope you've read Reinhard's earlier threads here where I chimed in on my own build and troubleshooting progress. I posted utilities for converting pdp-11 formatted pack images for use under PUTR. I have figured out but not yet written utilities for 12-bit pdp-8 formatted packs. I use my emulator on both 11s and 8s. So I can confirm it works on RL11, RLV12, and RL8A (and it should work on RLV11, just never actually did it.)

                      For historical reference, the other threads are http://www.vintage-computer.com/vcfo...RL02+Simulator and http://www.vintage-computer.com/vcfo...RL02+Simulator . The utilities I wrote are in post #39 of the second link.

                      Lou
                      Last edited by Lou - N2MIY; October 20, 2014, 04:21 PM.

                      Comment

                        #12
                        Originally posted by Lou - N2MIY View Post
                        It is annoying that the SDcard pins are not on 0.1" centers. What were they thinking?
                        They probably didn't think about 0.1" spacing for even a moment when designing the SD card form factor, because compatibility with breadboards and/or perfboard hasn't been a consideration in the consumer electronics industry for a long time.

                        Comment

                          #13
                          Sure, I was being sarcastic. Most likely the people working on the standard had never even worked with anything on 0.1" centers. We, however, are on the vintage computer forums.

                          Lou

                          Comment

                            #14
                            Originally posted by Lou - N2MIY View Post
                            Sure, I was being sarcastic. Most likely the people working on the standard had never even worked with anything on 0.1" centers. We, however, are on the vintage computer forums.

                            Lou
                            Drat! I appear to have fallen victim to Poe's Law. I shall atone by presenting a link to these breakout boards for sending newfangled parts into the pin pitches of yesteryear!

                            Comment

                              #15
                              Originally posted by Lou - N2MIY View Post
                              Coredump, I apologize for not responding to your earlier post, but have been swamped with other stuff (and will be for one more week.) I built Reinhard's old design and also did use an LVC244 for level conversion. The voltage dividers worked lousy for me. I had pulse shape distortion and crosstalk from the drive bus clock.

                              ...

                              For historical reference, the other threads are http://www.vintage-computer.com/vcfo...RL02+Simulator and http://www.vintage-computer.com/vcfo...RL02+Simulator . The utilities I wrote are in post #39 of the second link.
                              Thanks. I read threads you told me and found you have already applied LVC logic for level conversion, improving signal integrity.

                              I am not familiar with wire-wrapp, but it seems to me that tied wires potentially cause crosstalk.
                              For me, soldering SMDs is much easier than learning wire-wrapp. It allows to use 4-layer PCB with ground plane, generally reducing signal distortion.

                              coredump

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