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TDP158: Pins not used for application

Paul Antunes
Intellectual 2520 points
Part Number: TDP158

Dear Sir,

Can we leave HPD_SNK, SCL_SNK and SDA_SNK pins unconnected when not used ?

 External device is implemented with L/S integrated and ESD protection and so no need for these pins.

 

thanks

Paul

  • 0
    TI__Mastermind 23815 points
    Hi Paul,

    If the customer is not using the L/S from TDP158, they have to use snoop mode in both DDC and HPD.
    HPD_SRC -> floated
    HPD_SNK -> connected to HPD from connector
    This allows TDP158 to enter power down state when there is no display connected.

    SCL_SRC/SDA_SRC -> tied to GND
    SCL_SNK/SDA_SNK connected to SCL/SDA from connector with 2k pull-ups to 5V
    This is needed to monitor de TMDS_CLK ratio

    Not using snoop mode would require extra monitoring and configuration by I2C.

    Regards
  • 0 in reply to Moises Garcia
    TI__Intellectual 2520 points
    Hi Moises,

    Then next question is about configuration of the device when HPD_SNK, SCL_SNK, SDA_SNK are connected and HPD_SRC, SCL_SRC, SDA_SRC not used.

    What is the simplest way to configure the device for such application?
    is there material describing configuration over I2C ?

    thanks
    Paul
  • 0 in reply to Paul Antunes
    TI__Mastermind 23815 points

    Hi Paul,

    When the device is connected in snoop mode (HPD_SNK, SCL_SNK/SDA_SNK are connected, HPD_SRC is floated, and SCL_SRC/SDA_SRC are tied to GND), you don't need extra configuration, please use snoop mode.

    If you don't want to use HPD and DDC at all, you can leave HPD_SNK and HPD_SRC floated, SCL_SRC/SDA_SRC are tied to GND and SCL_SNK/SDA_SNK connected to 5V with 2k pull-ups. Then you will have to: disable HPD automatic power down(0x09[2]) and

    Disable HPD automatic power down(0x09[2])

    Disable DDC training (0x0B[0])

    Set the right mode of operation HDMI1.4 o HDMI2.0(0x00B[1]) this will change when the data rate changes

    Using snoop mode is the best choice.

    Regards