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  • Gen4-uLCD-70DT questions

    Hello,

    We've been using the Diablo16 70DT for over a year, and now we are migrating to the newer gen4 version. As of now we are facing two problems with the migration:
    1. Since all the other hardware was built to function with the older models, which had the 30-pin header, now we have to adequate all the other hardware pieces to the new 30-way FPC cable. As a temporary measure and as means to check if everything still works with the newer displays before changing the rest of the hardware, we bought a gen4-PA board to solder all the wires from the old hardware - and here comes the first problem. We were using the 70DT to send and receive commands through serial communication using COM0, which worked fine with the old display. Using the newer gen4 display, we can see how the commands sent by the display are in the correct TTL range (0~3V3), but when receiving commands the signal is in 1V5~3V3 range, which causes the gen4 to be unable to receive them correctly. Doing some tests, the problem narrowed down to either the gen4 display, the FPC cable or the gen4-PA (but we bought a new gen4-PA board and the problem is still there. Checking the gen4-PA datasheet, it seems the RX0 and TX0 lines have a 68Ohm resistor on them, but we doubt it's that because then there would be a failure in both the RX and TX lines).
    2. We are planning to use a 5kNTC to monitorize the temperature of a piece of equipment. According to the gen4 datasheet, only PA0 to PA3 can be set as analog inputs with 0 to 3V3 range. Our team looked into it and it seems there are some issues with the input voltage range: the estimated resistance range of the NTC we will use is 4K~30K, according to calculations, feeding the circuit with 5V would mean a voltage range of 0.8V to 3V3, but if something happens with the NTC the analog pin will receive 5V, way out of tolerance. On the other hand, if we feed the circuit with 3V3 to prevent burning the input, the voltage range would drop to 0.5V to 2V, giving a much smaller resolution. Is the datasheet accurate on the tolerance of the analog pins?
    Thanks for your time.

  • #2
    Hi,

    I have tested a communication between an Arduino with DIABLO 70DT and DIABLO gen4 70DT and both displays received the same data. Can you explain more of your setup (connections and power source) while testing so that I can simulate here on my end?

    Just like what is documented in the datasheet, the maximum tolerable voltage of the analog inputs is 3.3V only. It could be connected to 5V but this is not recommended as it destroys the ADC of the display. You might find this useful for better resolution: https://forum.4dsystems.com.au/forum...rast#post62362.

    Best Regards,
    Eran

    Comment


    • #3
      Hello,

      The setup is as follows (I hope it is somewhat understandable): the device we're using receives 24V from an external conversor, which is then further converted to 5V 2A using a DC/DCThe converter (R-78B5.0-2.0) to feed the display on a spearate board which acts as a bridge between the display and the driver board. The driver board requires RS232 signal, so the bridge board features a max3232-type chip to convert TTL to RS232. The bridge board connects to the 70DT via a 10-way IDC type cable, connected to a small board that attaches to the 70DT's 30-pin header. With the gen4 displays, we bought a few gen4-PA boards with the intention of keeping the bridge board as is for the moment, so we hand-made a small board that connects the IDC cable to the gen4-PA pins, and the gen4-PA connects to the gen4-70DT through the supplied FFC cable.

      Everything works except the serial communication when using the gen4-70DT, and the device works properly with a 70DT. We unwired everything on the hand-made board leaving only the bare minimum for the serial communications to work - +5V, GND, TX0 and RX0. Using the bridge board's test points, we can check the TTL signal sent from the gen4-70DT (correct signal), after converting to RS232-type (correct signal), the received RS232 signal from the driver board (correct signal) and after converting to TTL (wrong signal). Since the driver board sends information on startup via serial, we tested the received TTL signal without wiring the gen4-PA or the gen4-70DT; the signal received was correct TTL-level so that should rule out any issues on the other hardware (and to reiterate, the device including serial communcation works fine using a 70DT).

      Since we ended up with three gen4-PAs, a coworked tampered with it and found out that cutting the path leading to R5 on the gen4-PA (corresponding to the RX0 signal) makes the received signal be properly TTL-level.


      Thanks for providing us with that link, we'll take a look.

      Unfortunately I'll be on leave for two weeks, please excuse the delay on coming back to you.

      Thank you for your time.

      Comment


      • #4
        Hi,

        Upon review, and to confirm your guess as well, the 68-ohm resistor in RX line is not the reason of the unusual behavior of your setup as this resistance value is present in both DIABLO 70DT and gen4 DIABLO 70DT.

        This, however, can further be tested using a gen4-IB instead of the gen4-PA. This simplifies your connections and complexities that the integration of your hardware setup and the display is having. Gen4-IB has lesser components to be looked on to and might solve the issue that you’re having. Only, unlike gen4-PA, you wouldn’t be able to connect I/O peripherals directly.

        Another option is using the other pins of gen4-PA as your RX/TX instead of the hardware Serial RX0 and TX0. More information can be found here:
        I have also attached a test program for you to try if you’re receiving incorrect RX0 data.

        Hope this helps and best regards,
        Attached Files
        Eran

        Comment


        • #5
          The Gen4-PA is designed to break out the I/O to the display.

          However, TX and RX are connected to the on board USB to Serial converter and thus the break out of those signals is meant for monitoring purposes only.

          If you want to feed serial into TX and RX then you should remove R5 (definitely) and R6 (optionally).

          If you wish to reconnect them later, then, at a pinch, you can use a solder blob

          Alternately, as Eran suggested, you could use alternate I/O pins to communicate with the display.
          Mark

          Comment


          • #6
            Hello,

            Thanks for the suggestions. In the end we ended up buying the components to make a test board to connect the Gen4-uLCD with our device directly through a 30-way FPC-type connector (using the gen4-PA datasheet as guide), which seems to be working fine. Thanks for your support.

            Comment


            • #7
              Hi,

              Glad to know that you have worked on the problem. You can always ask if you need more clarifications.

              Best Regards,
              Eran

              Comment


              • #8
                hello, I have acquired a display gen4ulcd-50dct-clbar. I have windows10. I downloaded and installed workshop4. When connecting the display via USB to the PC, it turns on but I can not communicate with it. In the "COM" menu, it asks me to select a com port. But there is no port that I can select. The status point is always purple. Can you tell me what I have to do to be able to communicate with the display? Thanks

                Comment


                • #9
                  Hello,

                  Welcome to the forum,

                  It may be that the driver for the 4D USB progarmming adapter gen4-PA / UPA or 4D programming cable is not installed. Could you please check in Windows Device Manager to see the status of the Com port associated with the adapter. If you need a driver you can download it here.

                  https://www.silabs.com/products/deve...ge-vcp-drivers

                  Best regards

                  Paul

                  Comment


                  • #10
                    Hello Paul,

                    Thanks for your fast response. Now it works :-). I have managed to perform several functions with the display but I tried to insert a video in my project but it does not let me select a video to add. What do I have to do to be able to add and watch videos with my display. Thanks

                    Comment


                    • #11
                      Hello,

                      It would be best to use a .wmv video file. If your video isn't .wmv you can use an online converter or utility to convert to a .wmv. These appnotes will help with using videos and SD card widgets on your display.

                      https://www.4dsystems.com.au/appnote/4D-AN-00007/

                      https://www.4dsystems.com.au/appnote/4D-AN-00069/

                      Best regards

                      Paul

                      Comment


                      • #12
                        Hello Paul,

                        Thank you for you information. I am still new and y have to familiarize myself slowly but surely :-)

                        Best regards
                        Alex

                        Comment


                        • #13
                          Hello Paul,
                          I want to see a video in full screen on my gen4ulcd-50dct-clbar display.
                          I have tried to do it in several ways but it doesen't work how y want.
                          The video is always too slow. If I see it in reduced size it looks good.
                          I have transformed the original video to .wmv in low resolution and removed the sound.
                          Maybe I have to use an external host as an arduino to get it.
                          What can I do?
                          Thanks

                          Comment


                          • #14
                            Hi,

                            Yes it will be slower at full screen. This is due to the amount of 16 bit pixels being read from the SD card for each frame and it is the SD card read speed that limits the framerate even though this is done very quickly.

                            800 x 480 x 2 = 768000 bytes of data for each frame.

                            On a Diablo display like yours, it is capable of 1.2Mpixels/sec so 800x480 will be about (1200000/(800*480)) 3.125FPS

                            I hope this helps

                            Best regards

                            Paul

                            Comment


                            • #15
                              Hello Paul,

                              thanks for your response.
                              Is there any other way to show the video in full screen size p.e due tu an external horst controller?
                              Do you have some project for the future that can do this?

                              Thx

                              Comment

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