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TMDS442 Under I²C Control

Richard Bentley
Prodigy 20 points
Other Parts Discussed in Thread: TMDS442

I am designing in the TMDS442 for a customer of mine. Two inputs will be used and both outputs which will both select the same input.

When in I²C control mode and Source Plug-In Status Register Bit Decoder Bit 4 (5V_EN) is set to 1. Does this then override the OE for the sink port - Bit 2 in the Sink Port Register Bit Decoder and enable the TMDS output selected by Bits 0-1 when a Hot Plug is detected in the Source Plug-In Status Register (Bits 0-3)?

When in I²C control mode, unless I have missed something, there does not seem to be a register bit to detect Sink Hot Plugging. In port control mode, the status is available on pins 49 and 68. I was trying to design in power save features in that the appropriate sink OE would only be active when hot plugged. In the design, one HDMI sink will be active all the time and the other on demand.

  • 0
    TI__Guru* 76130 points

    Hello,

    When in I²C control mode and Source Plug-In Status Register Bit Decoder Bit 4 (5V_EN) is set to 1. Does this then override the OE for the sink port?

    No, the 5V_EN does not override the OE#, you still need to set the OE# bit in the "Sink Port Configuration Register", the 5V_EN only enable/disable the 5V_PWRx bits.

    Regarding the HPD control, you are right, the HPD_SINK is not mapped to a I2C bit, however, depending on your implementation you could "hardwire" the design so when the HPD1 is not active then the SINK2 will be enabled.

    Regards

  • 0 in reply to Elias Villegas M.
    Prodigy 20 points

    Hello Elias,

    Thank you for your speedy reply and explanations. I am slightly surprised that all control features are not available under I²C control but will around this now that I am aware of it.

    Regards,

    Richard