Activity Forums Questions & Troubleshooting Hardware Problem with SDA and SLA pins for I2C LCD Screen

  • Problem with SDA and SLA pins for I2C LCD Screen

     Lukas updated 3 years, 3 months ago 3 Members · 4 Posts
  • Antonio

    January 29, 2021 at 4:53 am

    I’m connecting an LCD screen with an I2C driver to the controllino mega. A few months ago it was working fine, and now there’s no signal being sent to the LCD. It turns on fine, but no text shows when connected to SDA or SLA pins. I also tested 2 of the same LCDs with the same driver on an Arduino Mega and it worked fine. I also tested the I2C detector and it got stuck scanning, not even printing if one was connected or not. The scanner worked fine for the driver and screen on the Arduino Mega. Even with nothing connected to the X1 pins on the controllino mega it wasn’t running. Are the SLA and SDA pins broken? Is the I2C connection busted? Any suggestions for work around? Any ideas for how it broke? I also asked this question in software since I’m not sure if it’s a hardware or software issue.


  • mr-controllino

    January 29, 2021 at 6:11 am

    Hello Antonio,

    Can you please check if the pins are working properly? So can you please make a “blink” on the pins and see if the 2 pins are switching accordingly?


    • Antonio

      January 29, 2021 at 7:07 am

      The pins on the Controllino Mega for SDA and SCL pin are connected to “X1” in the pins section, so unfortunately I can’t see them being actuated by any blinking LEDs. It seems to be showing continuity and a constant voltage between the SDA, SCL pins and the ground. Image of the pinout to show what I mean to “X1”, with the SDA and SCL pins: “”

      • Lukas

        February 16, 2021 at 1:58 pm

        Hello Antonio,

        I assume that Marco means to configure the pins 20 and 21 as digital outputs and try to trigger them to LOW and HIGH and measure the output voltage.

        In addition – may I ask you to share the I2C detector sketch you use?



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0 of 0 posts June 2018