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DS90UB935-Q1: I2C communication through serdes.

Zhaocai XIANG
Prodigy 70 points
Part Number: DS90UB935-Q1

Tool/software:

Hello 

For the I2C bidirectional control channel in the serdes, does the serializer need interrupt the deserializer when serializer need to request communication? Qr the serializer and deserializer can both act masters at different time?  I am a little bit confused after I read , can you help to explain it? 

Thanks

  • 0
    TI__Guru** 107530 points

    Hello Zhaocai,

    As stated in the App note, there are three types of operations supported for I2C transactions with the bidirectional control channel, Local, Remote, and Remote Slave. 

    The function depends on your system settings. If your I2C master is located on the DES side or on the SER side. Each device can function as an I2C slave proxy or master proxy depending on the I2C mode of operation. 

    Please refer to this App note for more clarification on each case.

    SNLA222_I2C Over DS90UB913-4 FPD-Link III with Bidirictional Control Channel.pdf

  • 0 in reply to Hamzeh Jaradat
    Prodigy 70 points

    Hello Hamzeh

    I've read the document which you share, but I'm still feel confused.
    Question1: If the serializer inside the camera want to send some status to the host controller, can the camera initiating communication to the host controller or the deserializer?
    Question2: Additionally, If a sensor on the remote I2C want to send status to the host controller, is an interrupt GPIO port necessary between sensor and serializer?
    Could you please explain it in more detail?
  • 0 in reply to Zhaocai XIANG
    TI__Guru** 107530 points

    Hi Zhaocai,

    Zhaocai XIANG said:
    Question1: If the serializer inside the camera want to send some status to the host controller, can the camera initiating communication to the host controller or the deserializer?

    Does your camera have an MCU? Otherwise, how would you initiate an I2C transactions from slaves?

    Zhaocai XIANG said:
    Question2: Additionally, If a sensor on the remote I2C want to send status to the host controller, is an interrupt GPIO port necessary between sensor and serializer?

    I think using a GPIO for this kind of interrupt is the best idea. Otherwise, you need to read the status registers from the image sensor on a frequent basis.

    But the interrupt GPIO will work as standalone, it does not need I2C to communicate.

  • 0 in reply to Hamzeh Jaradat
    Prodigy 70 points

    Hello Hamzeh

    I'm clear for question2 now, thanks!

    But for question1, our cameras have no MCU inside. Based on this design, I wonder how could the serializer send urgent warning(status or error) to the host controller in the function safety application?  Does the host controller read the status registers from the image sensor frequently though the FPD-LINK control channel?

  • +1 in reply to Zhaocai XIANG
    TI__Guru** 107530 points

    Hi Zhaocai,

    Urgent SER warnings such as voltage sensor levels, temperature sensors levels, errors, status..etc are all part of the diagnostic registers within the SER, which you can program an alarm flag to be output on the DES interrupt pin to the SoC.