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DS90UH926Q-Q1: interrupt

David Mckinney
Expert 6550 points
Part Number: DS90UH926Q-Q1

We are using a DS90UB929 as the serializer for video to drive to a display with a DS90UH926.  We are looking for to get an interrupt when the display is unplugged.

It appears that interrupt will be generated when the display is connected, but we have not been able to see this happen.  Can you advise if you can interrupt when unplugged, and if there is an application note on this?

Also, is the DS90UB929 Hot Plug Detect (HPD) signal used in this function?  

  • 0
    TI__Mastermind 32070 points

    Hi David,

    What do you mean when "display is unplugged"? Are you saying when the UB926 doesn't detect the video and send the interrupt back to the SoC? The device is not capable of detecting if there is a video or not. However, as long as there is an established link and lock, the backchannel can be used to perform the interrupt such as INT_IN and INT_REM pins.

    You might want to use external device detecting whether the TCON has the display or not then handle it in our FPD-Link device.

    Aaron

  • 0 in reply to Aaron Heng
    TI__Expert 6550 points

    Hi Aaron;

    Yes, they are trying to determine if the display is plugged in or not.  Can you provide more details on the back channel use to perform the interrupt such as INT_IN and INT_REM pins.  I do not see these pins on the DS09UH926.  Can you explain how to use this with TCON?

  • 0 in reply to David Mckinney
    TI__Mastermind 32070 points

    Hi David,

    The INT_IN pin is listed as PIN16 of the DS90UB926. This pin takes your input from the TCON. Once this pin is flagged, it will pass on to the serializer of the DS90UB929 REM_INTB on PIN40 via back channel where the SoC can fetch this pin if it is LOW or HIGH.

    Most display has the TCON where it has the microcontroller and deserializer such as DS90UB926 on the same board. They use external device to monitor the present of the video. If there is no video present, they trigger the INT_IN pin in UB926. This information will pass on to the SoC and letting it know that there is no video.

    Here is the section talk about how to configure the interrupt in 8.3.19 Interrupt Pin in UB926.

    Hope this helps. Let me know if you have further questions.

    Aaron

  • 0 in reply to Aaron Heng
    TI__Expert 6550 points

    Thank you for such the through answer.

    I had one simple additional question which boils down to:  Can you output from the ‘929 a loss of link between the ‘929 and ‘926?

     

  • 0 in reply to David Mckinney
    TI__Mastermind 32070 points

    Hi David,

    Yes, if there is a link lost, you can check the status register 0x0C[4] and 0x0C[0].

    Aaron

  • 0 in reply to Aaron Heng
    TI__Expert 6550 points

    Thanks Aaron;

    Last question, is there any way to output this to a hardware interrupt like the HPD pin?

  • 0 in reply to David Mckinney
    TI__Mastermind 32070 points

    Hi David,

    Unfortunately, there is no similar interrupt like HPD pin. If you can't established the link and lock, there is no way for the serializer communicate to the deserializer.

    Aaron