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DS90UB948-Q1: DS90UB948-Q1 LVDS pair Swapping option

ismail pp
Prodigy 50 points
Part Number: DS90UB948-Q1

 is it possible to swap any of the LVDS out put (8 pairs ) line in DS90UB948  deseriliazer ,for easy of PCB layout routing  . 

in data sheet mension some SWAPing option is this related with LVDS line swap ?

 

  • 0
    Prodigy 50 points
    one more question : Do we need to do the length/Impedance matching in LVDS pair lines ?
  • 0 in reply to ismail pp
    TI__Intellectual 1565 points
    Hi Ismail PP,

    I tracked down the details of the swap function. It puts DOUT1 on DOUT0 and DOUT0 on DOUT1, but you can not individually assign channels.

    LVDS is differential and requires length matching and impedance matching. Make all channels in a lane match each other within 5mils or better.

    Mike
  • 0 in reply to Mike Leister
    Prodigy 50 points

    Hi Mike

    As you told we can swap Dout 0 and 1 , then what about other channels Dout,3,4,5,6,7.  ?

    Or can we assign Dout0 to Dout7?

  • 0 in reply to ismail pp
    TI__Intellectual 1565 points
    Ismail,

    Let me start over.

    You have two input ports. In dual mode, the deserializer takes a bit from port 0, then a bit from port 1, etc until it has 8 bits and then puts them on Dout.

    Dout_0 = Rin0 bit 0
    Dout_1 = Rin1 bit 0
    Dout_2 = Rin0 bit 1
    Dout_3 = Rin1 bit 1
    Dout_4 = Rin0 bit 2
    Dout_5 = Rin1 bit 2
    Dout_6 = Rin0 bit 3
    Dout_7 = Rin1 bit 3

    In dual SWAP mode, this becomes:

    Dout_0 = Rin1 bit 0
    Dout_1 = Rin0 bit 0
    Dout_2 = Rin1 bit 1
    Dout_3 = Rin0 bit 1
    Dout_4 = Rin1 bit 2
    Dout_5 = Rin0 bit 2
    Dout_6 = Rin1 bit 3
    Dout_7 = Rin0 bit 3

    The processor parses out the video from the two ports and sends them to displays/etc. The effect of swap will be to redirect the video streams to the other display, swapping what you see on the displays.

    There is no way to arbitrarily select which Dout has a particular bit assignment.

    Mike