• State Resolved
  • Locked Locked
  • Replies 9 replies
  • Subscribers 32 subscribers
  • Views 4011 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPD12S016: HDMI HPD signal was toggled when HDMI cable was plugged out, then plugged in.

Li Cao55
Prodigy 80 points
Part Number: TPD12S016

Dear Sir,

I designed one product with Netra and TPD12S016.  I found one issue when the user connected our product to the TV from Skyworth vendor.

The issue is as following.

1. The display is normal when I powered up our device which connected to Skyworth TV with HDMI cable. The resolution is 1080P60.

2. Then, there is no display when I plug out the HDMI cable, then plug in HDMI cable.

3. I tested the HPD signal with nothing display and found the HPD signal was toggled.  Pls refer to the schematics and the snapshot of wavform of HPD signal.

Could you please give me any hints on this HPD issue? Thanks.

 

  • 0
    TI__Expert 8420 points

    Thanks for your question, will reply you soon

  • 0 in reply to Michael Tan
    TI__Expert 8420 points

    Hi ,

    Do you know the CT_HD and LS_OE  pin voltage during this operation?

    I found you pull up this two pin to 3.3V voltage.

    Is that the Yellow channel is HPD_B ? How about HPD_A?

  • 0 in reply to Michael Tan
    Prodigy 80 points

    Hi Michael,

          You're right. The yellow channel is HPD_B. You can confirm that with about +5.0 voltage level. The HPD_A signal is same as HPD_B but the +3.3V voltage level.

           If I pulled the CT_HD to ground, both the HPD_B and HPD_A are pulled to low. 

           No longer the HPD signal was toggled any more.

  • 0 in reply to Li Cao55
    TI__Expert 8420 points

    Hi Cao,

    The CT_HD is enable control for HPD_A connect to HPD_B output 

    I think the problem is the MCU side and you  find the HPD_A toggled.

  • 0 in reply to Michael Tan
    Prodigy 80 points

    Hi Michael,

               You meant that MCU side is HDMI source side or HDMI sink side?Thank you.

  • 0 in reply to Michael Tan
    Prodigy 80 points

    Hi Michael，

    If the MCU side means the HDMI sink side, my question is that there are two HDMI sources in our product.

    There is no problem with the combination of ADI IC+TPD12S016+TV(HDMI sink side).

    And there is problem with the combination of Netra IC++TPD12S016+TV(HDMI sink side).

    How to think about it?Thank you.

  • 0 in reply to Michael Tan
    Prodigy 80 points

    Hi Michael，

    If the MCU side means the HDMI sink side, my question is that there are two HDMI sources in our product.

    There is no problem with the combination of ADI IC+TPD12S016+TV(HDMI sink side).

    And there is problem with the combination of Netra IC+TPD12S016+TV(HDMI sink side).

    How to think about it?Thank you.

  • 0 in reply to Li Cao55
    TI__Expert 8420 points

    Hi Cao,

    I have no idea why the the Netra combination will have problem.

    The TPD12S016 just open the data switch between HPD_A and HPD_B.

    It can't affect the data communication.

  • 0 in reply to Michael Tan
    Prodigy 80 points

    Hi Michael,

    I agree with your point of view about the functionality of TPD12S016.  It seems like that this problem is not relevant to TPD12S016. So I will close this ticket. Thank you for your support as always.