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TMDS181: Connecting multiple TMDS181 through I2C

Jerry%20Leung
Intellectual 905 points
Part Number: TMDS181

Hello,

I have a couple questions I would like to verify:

  1. When using 4 TMDS181, is it required to use them in I2C enabled mode in order for them to be addressable on the same I2C bus?  It appears that the A0/A1 strap pins are not usable to set distinct I2C addresses unless I2C enabled mode is set.

  2. The TX termination strap pin can auto-detect termination if chip is in strap modes, but I would also like to verify whether or not auto-detect termination available if the chip is in I2C mode? I saw some details below from the datasheet but just want to verify that it will auto-detect when it's not connected.

Thanks and best regards,

Jerry Leung

  • 0
    TI__Mastermind 23815 points
    Hi Jerry,

    In GPIO mode the device is still addressable from I2C interface, but the configuration from the pins is not overridden.
    You can set I2C addres with pins A0/A1, but changin A0 will modify the equalization.

    In I2C mode there is no Automatic Tx termination selection

    Regards
  • 0 in reply to Moises Garcia
    TI__Intellectual 905 points
    Hi Moises,

    Just wanted a little clarification on #1.

    Does this mean that with I2C_EN = LOW, we can still set four distinct I2C addresses via pins A0 and A1?
    Also if I2C_EN = HIGH, then what is the equalization set to? Or is it just set via I2C configuration?


    Thanks,
    Jerry
  • 0 in reply to Jerry%20Leung
    TI__Mastermind 23815 points
    Hi Jerry,

    Yes, when I2C_EN=LOW you can still set four I2C addresses via A1 and A0/EQ, if you change A0 you will change EQ too. GPIOs configure the device.

    If I2C_EN=HIGH, EQ can be adaptive or static, if it is adaptive TMDS181 select EQ without notifying which value it selected, if it is set fixed you select EQ in register 0x0D, this is controlled by I2C.

    Regards