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DS90UB947-Q1: DS90UB947-Q1 mapping mode

Terry Liang
Intellectual 1990 points
Part Number: DS90UB947-Q1

Hi team,

customer use UB947 pared with UB948. at first they configure the mapping mode of UB948 the same as the display panel spec(MAPSEL=L), and the mapping mode of UB947 is also the same as UB948. But distortion occur in display. then they configure mapping mode of UB948 different from display panel and UB947(MAPSEL=H). as a result, display can recover. the customer wonder:

1. can you please explain it from the internal operating mechanism level?

2. and is it recommended to configured the mapping mode of UB948 different from the display panel?

3. if not, what's your suggestions? 

4. how to configure the mapping mode of UB947 and UB948 if the mapping schemes of video stream signal from SoC is different from display panel spec? 

thanks!

  • 0
    TI__Genius 12866 points

    Hi,

    The 947 mapping mode need to match the video received by 947. 948 mapping need to be the same at the display requirement. 

    Do you know which mapping method the source video is using?

    Best Regards,

    Charley Cai

  • 0 in reply to Charley Cai
    TI__Intellectual 1990 points

    Hi Charley,

    Thanks for your feedback. 

    1. if the source video is JEIDA and the display panel is VESA. should UB947 map with JEIDA and UB948 map with VESA?

    2.The customer only design the panel side. the display panel is VESA, and they know that UB947 is Open LDI Mapping(VESA). But when they configurated UB948 MAPSEL=H(VESA), the display is abnormal, while configurated MAPSEL=L(JEIDA), it works. they are not sure which mapping method of the source video using.

    Can you please explain the mapping principal? thanks!

  • 0 in reply to Terry Liang
    TI__Guru** 103215 points

    Hello Terry,

    There are some discrepancies within the industry on the terminology used for VESA, JEDIA, etc. Some vendors use the opposite terminology, so it is useful to look at the bit mapping diagram and compare to the bit mapping diagrams in the 947/948 datasheets. If you can post a picture here, then we can also help to review which setting to use on the serializer side and deserializer side. Generally speaking, you want to match each MAPSEL setting on each side to what mapping is used on that side I/O like you mentioned in #1. 

    Best Regards,
    Casey 

  • 0 in reply to Casey McCrea
    TI__Intellectual 1990 points

    Hi Casey,

    thanks! The display panel mapping diagrams in the datasheet is as below. According to this, UB948 MAPSEL should be H. while the result is opposite. the display is normal only when MAPSEL is L. namely, UB948 mismatch the display panel can work. Does it mean UB947 also mismatch with video source. So the mapping method reverse twice and then it can work? dose it make sense? thanks!

  • 0 in reply to Terry Liang
    TI__Guru** 103215 points

    Hello Terry,

    Yes I suspect your comment is correct. 947 side is mismatched with the source so when you mismatch twice by flipping the 948 configuration, then it is correcting the mapping end to end. 

    Best Regards,

    Casey