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DS90UB949-Q1: Internal HDMI control without I2C from host

SANGRAE LEE
Prodigy 10 points

Part Number: DS90UB949-Q1

Hi! I am trying to use DS90UB949TRGCTQ1 with DS90UB948TNKDTQ1 without I2C from host.

I can see what I cannot do without I2C such as HDMI RESET. However, I cannot see how it works without I2C.

It is explained briefly. I would like to make sure it would work properly without I2C.

Could you tell me how it would work?

I could check there is an internal control from DS90UB949-Q1 datasheet attached below.

Regards,

Sangrae

  • 0
    TI__Guru** 103215 points

    Hello Sangrae,

    The 949 device always needs local I2C control - this feature specifically is related to the HDMI state machine specifically. It is possible to disable the internal HDMI state machine and control all HDMI state transitions and behavior via I2C instead of letting the internal state machine operate autonomously. In general we do not recommend to do this outside of a debug environment and the recommended mode for production is to use internal HDMI control. However there is no way to get around the requirement of having a local I2C controller attached to the 949 as that is a hard requirement for this device to operate, specifically so that the device errata can be applied during startup. 

    Best Regards,

    Casey 

  • +1
    Prodigy 10 points

    Hi Casey,

    Thank you for you answer.

    I am a bit confused of what you are talking about.

    My question was an operation without I2C from a host (MCU, MPU).

    I had a look at the datasheet again and it seems the I2C on the datasheet is I2C from HDMI.

    I think you are also talking about I2C from HDMI.

     

    1) Is there the I2C interface pin shown above I2C from HDMI or a host(MCU, MPU)?

    2) If the I2C is interface from a host, is there a Linux interface for I2C?

    The board runs in Linux

    3) If the I2C is interface from HDMI, is it okay to run without I2C from host?

    On the datasheet, there are RESET and other functions via I2C.

    Regards,

    Sangrae

  • +1 in reply to SANGRAE LEE
    TI__Guru** 103215 points

    Hello Sangree,

    1) It can be either or both for the purposes of the specific table you are mentioning, but from a more broad perspective, the minimum requirement is that this part needs an I2C connection to a host MCU/SoC to apply device configurations and device errata during boot even unrelated to the HDMI interface 

    2) If you are asking if we provide SW drivers, that is not something we typically supply from the TI side, however if you need any assistance in how to program specific features of the device, then you can reach out to us for help as you develop your own SW driver. The datasheet should contain all relevant information for how to program the device 

    3) No, I2C connection is required for this part in order to implement the device errata sequence at a minimum 

    Best Regards,

    Casey