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BBB and 4DCAPE-4.3T cursor jumping

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  • BBB and 4DCAPE-4.3T cursor jumping

    Dear sir,
    We have been using 4D-Cape 4.3T HW (rev 1.2, 2015) for some months now with BBB Rev c, Debian 7.6 without any problems.
    However, the latest displays we bought have the jumping cursor problem even with the same BBB hardware (no other capes) and same software.
    We have exchanged the display and got a new one from RS but this one also has the problem.
    This is very worrying to us and the evidence is pointing to a hardware related problem or else a faulty batch.
    Could you please have a look into this ?

  • #2

    I am very sorry to hear you are having these problems.

    Can you please provide the serial number of 1 of the units which is working correctly, and then 1 of the units which is not working correctly?
    How many units do you have in total which you are unhappy with?
    Are they all Revision 1.2 hardware, both correctly working units and apparent faulty units?

    Can you please provide a link to the image you are running on your BBB (if there is a premade image available), and we can try and test that same image here.

    If there is any chance you can record a short video clip illustrating the issue, and upload it to an unlisted (not private) youtube listing, and provide the link, that would be very helpful.

    Kind Regards


    • #3

      SN of a good display: 15090516
      SN of a bad display: 15080791 (jumping cursor)

      We had about 6 units working and they are in the field working fine.
      We ordered another 2 (from RS) and both have the problem.
      We have another 2 ordered (from Conrad) for a project that must be working next week...


      [email protected]:~$ lsb_release -a
      No LSB modules are available.
      Distributor ID: Debian
      Description: Debian GNU/Linux 7.9 (wheezy)
      Release: 7.9
      Codename: wheezy

      I tried also 7.4, 7.6 and 7.8, all the same result.
      Video is difficult but you can touch the screen anywhere, the cursor moves to the new position but after a random time the cursor moves back to the far left of the display and stays there.

      Hopes this helps,



      • #4

        Oops, now with full text for the link:




        • #5
          Thank you Luc for the information.

          This is strange and again I apologize for this.
          We can certainly RMA the units, but if there is somehow a faulty batch then you may receive another like this - it is hard to know right now until we investigate.

          I will get my colleague Dario to make contact with you to discuss options.



          • #6
            Hi James,

            I'm the colleague of Luc and we need a solution ASAP.
            As Dario has left the company and no respons from Doff, Can somebody else look into this?
            Old boards version 1.0 and 1.1 are working fine.
            Rev 1.2 boards have the jumping cursor problem.


            • #7
              Hello Eddy,

              I'll be sending you a reply thru email in a short while.



              • #8
                We have the same problem with H/W rev 1.2. Perhaps you could post the solution here so that others that search for this would know if it is a hardware or software issue.



                • #9
                  Hello Glamprecht,

                  I am sorry to hear that you are having a problem with your 4D-CAPE-43T. Unfortunately the touch algorithm on the Beagle Bone Black is not able to filter out noise that may come from the touch panel of the 4DCAPE-43T. Perhaps other forum users who have expertise with the Beagle Bone Black could post their solution.

                  If you intend to initiate an RMA for your device, please open a ticket using our contact page.


                  Thank you for understanding and best regards,


                  • #10
                    Soldering 1nF capacitors between the 4 Analog inputs and GND solves the jumping problem.


                    • #11
                      This cursor jumping seems to be a long standing issue with a product specifically designed for the BBB. I do not understand why a Company will not stand behind there product a provide a fix. We too (Crestron Electronics) is having this cursor jitter issue. I am surprised that after so much time (at least 1 1/2 years) a fix is not provided.

                      Can someone please provide a fix for this, or a vendor with a better touch display?




                      • #12
                        Some of these also have issues but you can try them.

                        Seeed Technology Co., Ltd
                        Circuitco Electronics LLC
                        SVTronics Inc.


                        • #13
                          Hi Mitch,

                          Unfortunately, the cursor jumping is a software issue. The BBB is open source, we only provide a hardware solution, and have no control over the software kernel, as per the Datasheet. We supply a hardware screen which attaches directly to the hardware pins of the BBB.

                          The issue you are experiencing is related to the use of the analog inputs of the BBB for the touch screen, and the drivers which are included in the kernel do not filter out the noise well.

                          We do have a new screen about to be released which doesn't use any of the analog inputs for touch on the BBB, and it has a dedicated touch controller.

                          I hope this helps.

                          Best regards