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DS90UB927Q-Q1: FPD-Link III Serializer

yunxia zhang
Prodigy 20 points
Part Number: DS90UB927Q-Q1

Dear,

my project like this:

 . Arm master   <-i2c-> < DS90UB927   TX >------- ==> <-i2c-> < DS90UB928  RX > ------ >  Touch Panel , sensor

 .  Arm master   <-LVDS-> < DS90UB927   TX >------- ==> <LVDS> < DS90UB928  RX > ------ > LCD 

  . Arm master   <-GPIO-> < DS90UB927   TX >------- ==> <-GPIO-> < DS90UB928  RX > >------ > LED_EN, TP_reset, int, pwm

      The problem is that master  has failed to reach DS90UB927  by  inquire i2c  address or  failed to reach DS90UB928  by  inquire i2c  address

sometimes, but  at this moment  LVSD is ok,  video is normal.

 

 

 

 

  • 0
    TI__Guru** 100950 points
    Hello,

    please make sure you have the right pull-up resistor values on IDx pin of the 927. Please check section "7.5.1 Serial Control Bus" in the datasheet.
    also you need to make sure that these are pulled-up to the right voltage level.
  • 0 in reply to Hamzeh Jaradat
    Prodigy 20 points
    Hi, Hamzeh
    Thanks for your reply.
    I had refered toTable 4. Serial Control Bus Addresses for IDx in the datasheet, but the problem remains unresolved.
    I had found the PDB pin of the 928 was pulled-up to the wrong voltage level 1.8V, Change the pull up voltage to 3.3V.
    Up to now , The sample has been working for 3 days, and it has been in normal condition.

    I wonder that the ARM master works at 1.8V and 927, 928 works at 3.3V,Is it necessary that all GPIOs require Voltage conversion?
    In my schematic. , VDDI/O pin of 927 is connected to 1.8V, Is it appropriate?
  • 0 in reply to yunxia zhang
    TI__Mastermind 30515 points
    Please check UB927/UB928 d/s page6/7/8, the I/O voltage can be supplied with 1.8V or 3.3V. if I/O pins (such as GPIO) is paired with 1.8V, the VDDIO can be supplied as 1.8V.

    Note: for LVCMOS I/F, please secure the voltage level is correct.

    best regards,
    Steven


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    Training on FPD-Link Serializer Deserializer devices and system: training.ti.com/fpd-link-learning-center

    More information on IVI or ADAS FPD-Link products: www.ti.com/.../overview.html