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DS90UB949-Q1: Issue with transmitting laptop display to display device while using DS90UB949 serializer device

Vivek Karna
Prodigy 130 points
Part Number: DS90UB949-Q1

Hello, TI community,

I have been using DS90UB949-Q1 Serializer to transmit my laptop screen display to the other end, which is an LCD display device (an attached DS-948 Deserializer is connected to the panel).

Now the problem is arising that when I am using Intel or NVIDIA-based display driver laptop, I can mirror the Laptop screen to the display device through a connected HDMI cable and LVDS cable. But when I use AMD based laptop, I am getting a jitter or noisy screen display on the display device and display device driver (see attached image below). 

         

Can you share with me why is this issue happening? While I am setting the display resolution of 1920x1200 using the EDID data bytes.

Please share the cause. 

Thanks & Regards,
Vivek Karna

  • 0
    TI__Mastermind 29535 points

    Hi Vivek,

    Are you also losing lock on the 948 or is lock stable (always high) - only image is distorted. 

    We can check a few things:

    • It's possible that your AMD laptop has a jittery clock - this would cause an issue if the CLK jitter is higher than the 949 input jitter spec
    • I suggest to do a thorough evaluation of the HDMI clock jitter to make sure it is meeting the datasheet specifications and please disable any SSC from the HDMI clock to rule that out as well 
    • Check that your EDID is correct 
    • Try changing MAPSEL settings on 948 side (FPD_TX_MODE Register (Address = 0x49)) - try both MAPSEL = H and MAPSEL = L to see if there is any difference

    Regards,
    Fadi A.