• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 33 subscribers
  • Views 947 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

DS90UB948-Q1: D_GPIO Drop Issue

Jim CHEN
Expert 4795 points
Part Number: DS90UB948-Q1

Dear Team,

My customer is using DS90UB947 and DS90UB948 on their board design.

They found that D_GPIO of UB948 drop suddenly then goes high without any reason. And then the panel will blink. But 947 D_GPIO1 is always high.

This issue sometimes happen, but sometimes it didn't happen all the morning.

My customer capture the issue by video as below.

(The upside line is 948 D_GPIO1, and the downside line is 947 D_GPIO1)

 

Here is the register of 947 and 948.

947 register:

ADD      DATA

0x17       0x9E

 

948 register: 

ADD      DATA

0x34       0x02

0x1D      0x05

0x1E      0x55

0x1F      0x05

Another question of 947 and 948,

My customer choose the internal timing source and spec HD 1080p 60 Hz to generate the test pattern to panel.

But why the status shows that it only has 40 frame/Second? Please see below figure.

We try to change the timing source to external source, then the status shows 60 frame/Second normally.

Therefore, could you help to provide the spec of internal clock to us? 

  • 0
    TI__Mastermind 30515 points

    Hi Jim,

    1. Can you check only D_GPI1 has sudden jump here? how about D_GPIO0/2/3? whether UB948's lock pin has toggle here?  as the display has flicking, it seems the UB948 receives bit error, which also could make D_GPIO1 data output error. also, how about the D_GPIO1 abnormal output pulse width?

    2. . can you check and adjust the internal pixel freq., and the format settings (total area, active area parameter) to match the 1920x1080@60fps timing request.

    best regards,

    Steven

  • 0 in reply to Steven(Shenzhen) Shi
    TI__Expert 4795 points
    Hi Steven,

    We met another issue recently.
    My customer used Analog LaunchPAD to generate the test pattern from UB947 to UB948.
    It can work normally when using Solid pattern (all white or all black or all red). And LOCK pin and the panel are stable.
    But if they use color pattern (mix black/white or mix black/red), LOCK pin start to toggling and the panel is flicking.

    The setting as below.
    Timing Source : Internal w/Ext. Clock.
    PCLK: About 148.5 MHz.
    Spec : HD 1080p 60 Hz

    If Timing source is Internal, then the issue has not been seen.
    Please help to give us some suggestion and comments.

    Thank you.
  • 0 in reply to Jim CHEN
    TI__Mastermind 30515 points
    Jim,
    it seems the PCLK under color bar test is too high. could you please help check the link channel quality? You also can reduce the PCLK freq. to try it again?

    best regards,
    Steven