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UCD90124A: Multiple Devices

Allan Fan
Expert 7110 points
Part Number: UCD90124A


Hi expert,

Customer used two UCD90124A on two boards. Host can detect each UCD successfully in the case. However when they connect the two boards together, host can not detect the UCDs. They are sure to use two different i2c address as 0x40 and 0x41. 

DS 7.4.13 mentioned cascading multiple devices method, but do we must to use cascading way? 

Please advise what might be possible causes and how to resolve it? 

Thanks,

Allan

  • 0
    TI__Guru 66700 points

    HI

    Cascading has nothing to do with the communication.

    i would suggest

    1. make sure there is no other device on the board has 0x40 or 0x41 address

    2. measure the i2c SCL/SDA to ensure they were pull up to 3.3V.

    3. Capture a i2c waveform when a detection is failed when connected to compare a standalone board. 

    Regards

    Yihe