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DS90CR288 some pins can not output

k m
Prodigy 165 points

Other Parts Discussed in Thread: DS90CR288A

Hi,everybody

Our Camera use cameralink interface,so in custom capture board,use ds90cr288 as the dencoder of LVDS.After test,the ds90cr288 could output FVAL LVAL CLK pefectly.But the portA7,portB7,portB6 (i just test all the pins expect SPARE,the three pins always are low )can not output,it is a fatal problem. it caused the image almost lost  all Y data。

then i refer to the Cameralink standard and ds90cr288 datasheet，the A7 B7 B6 are all from diff pair 3.

How can i fix this ?

Thank you

k m

  • 0
    Prodigy 165 points

    Hi,everybody

    After repalce a 100 ohm resistance in diff pair 3,The A6 disappear.Then I change it to 50 ohm resistance and 240 ohm resistance to test the resistance‘s effect.,and found nothing different.

    Somebody help?

    Thank you 

    k m

  • 0 in reply to k m
    TI__Expert 3175 points

    Hi Kim,

    The differential inputs should be terminated by 100-ohm  as close as possible to the pins.

    What is the length (or insertion loss) of your cable that connects the serializer to the de-serializer, and what clock rate you are using?

    Here are some debugging techniques I would recommend:

    Check that the serializer sends out the differential signals correctly before the cable.

    Check that the signal at the end of the cable looks acceptable (refer to figure 21 of datasheet, on strobe position).

    Can you confirm that you are using DS90CR288A?

    regards,

    TK Chin