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  • I2C stay high level

    Hi,
    I use a uLCD 32PT_GFX2-and I would use the I2C bus but I have a problem. I used an oscilloscope to observe SDA and SCL but remain high level, regardless of the component used (ISL12026 and SHT11). I tried several pull-up resistance values ??but it does not work.
    You will find below an example of the code used:

    [hr]
    HTML Code:
    I2C_Open(I2C_MED);
    pause(200);
    //I2C_Idle();
    I2C_Start;
    I2C_Write(I2C_ISL12026_ADDR_CCR);
    I2C_Write(0);
    I2C_Write(I2C_ISL12026_ADDR_START_RTC);
    I2C_Write(0x00); // Ecriture seconde
    I2C_Write(0x09); // Ecriture minute
    I2C_Write(0x08); // Ecriture Heure
    I2C_Write(0x10); // Ecriture jour
    I2C_Write(0x11); // Ecriture mois
    I2C_Write(0x12); // Ecriture année
    I2C_Write(0x00); // Ecriture jour dans la semaine
    I2C_Write(0x20); // Ecriture Y2K
    I2C_Stop();
    I2C_Close();
    [hr]
    I don't understand.
    Did i forget something?
    regards
    Yann

  • #2


    Hi Yann,

    I'm not familiar with the devices you are using, there are some examples here
    of devices we know that work,

    http://www.4dsystems.com.au/code/index.php?node=79

    principally your code is the same (apart from missing parenthesis which I guess is a typo as it wont compile)

    Sounds like it could be a hardware issue - are you using a P1-EB expansion board?

    Check all the soldering on the connectors.
    Regards,
    Dave

    Comment


    • #3


      Hi Dave,

      Thank you for your response.

      I used this code examples for checked my code. In fact I forget parenthesis but its only in the post and not in my program.
      I don't use P1-EB expansion board.
      I checked all soldering and connections between µC and connector : OK.
      I also checked connection between connector and I²C components : OK.
      I disabled touch screen management, I created a new project to test the I²C without perturbation but SDA and SCL remain desperately at high level.

      I don't know what to do.

      Thanks for your ideas.

      Regards
      Yann

      Comment


      • #4


        Ok so just to double check..

        J2 pin 21 is SCL , J2 pin 23 is SDA, and when you run your code, both lines stay HI ?

        If this is the case, there are only 2 possibilities,

        Hardware failure or PmmC failure.

        First thing to try would be to reload the PmmC from here:-

        use this one if there is "("S I RXX" on the warranty label)"
        http://www.4dsystems.com.au/downloads/4DGL-Display-Modules/uLCD-32-PT(GFX)/PmmC/uLCD-32PT-I-GFX-R28.PmmC

        or use this one:-
        http://www.4dsystems.com.au/downloads/4DGL-Display-Modules/uLCD-32-PT(GFX)/PmmC/uLCD-32PTGFX-R28.PmmC
        Regards,
        Dave

        Comment


        • #5


          Yes, when my code run, both lines stay high.

          I've already reload PmmC so there are an hardware failure.

          Thanks for your time and your help.
          Best regards
          Yann

          Comment


          • #6


            Yann you can contact support either by emailing

            4dsystems dot com dot au and ask for a RMA to return

            or use:-

            http://www.4dsystems.com.au/contact.php contact support
            Regards,
            Dave

            Comment


            • #7


              Thanks, this is a good idea. I sent an e-mail.
              regards.
              Yann

              Comment


              • #8


                Just make very sure that you did download the very latest PmmC from the link below,

                On day 1 of the release, there was a mixup of PmmC files, if you were unlucky
                enough to download 2.8 PmmC on the first release day, it may be faulty.
                Regards,
                Dave

                Comment


                • #9


                  Hi Dave,
                  I just download PmmC and reload it but SDA and SCL stay high.
                  Regards,
                  Yann

                  Comment


                  • #10


                    What values of pull-up resistors are you using?
                    _______________
                    Best Regards,
                    Howard

                    Comment


                    • #11


                      I use 4k7 pull-up resistors but i tried with 1k, 3k3, 6k8 and 10k.

                      Regards
                      Yann

                      Comment

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