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.

  • TI Thinks Resolved

DS90UB948-Q1: Asking for the recommendation on DS90UB948/949 design

Mastermind 24735 points

Replies: 9

Views: 232

Part Number: DS90UB948-Q1

Hi team,

This is the follow up from last E2E post. Would you please help for RD’s two questions here?

 Here are the HW setup as below.

  1. Use Rasberry Pi HDMI output(resolution is 1920 x 1080)

Mode_sel0 = 1.275V

LCD panel show the following incorrect cut display. (original display is 1920 x 1080, LCD panel resolution is 1920 x 720)

Question:

  1. Why ALP device is incorrect if connecting the Raspberry Pi4 signal source?

Why there is no response if customer clicking Pattern generator and Register two tab?

 

 

2. Use NB HDMI output (output resolution is 1280 x 720). Would you please provide comment why the display is “black ” without any content?

Mode_sel0 = 1.275V

ALP GUI show the correct device information as highlighted in red

Customer change EDID to customer’s LCD panel spec and apply on the GUI. The LCD panel is “black” without any display.

Power cycle, the LCD panel still is “black ” without any display.

 

Customer also change internal / internal w/Ext. Clock. The situation is the same.

Here are the register 0x37.

 

 

 

 

 

 

 

 

 

 

https://e2e.ti.com/support/interface/f/138/p/853740/3177266#3177266

 

 BR,

Scott

  • Hi SHH,

    Please try to work your way backwards from the display to ensure functionality of each part of the signal chain.

    One way to step through the problem:

    Please use the timing information in the EDID profile to run patgen on the 948 and display. 

    Once that works, use patgen on the 949 via fpdlink to the 948 coupled to the display.

    With that working, then load the EDID profile information to the SRAM on the 949.

    Once that is working and confirmed, you may modify the raspberry pi to hard code the info or add EDID information in the chain using DDC.

    Please let me know if you run into any issues.

    Sincerely,

    Bryan Kahler

  • In reply to Bryan Kahler:

    Dear Bryan,

    I/m TPV-tech engineer, Alvin.

    Sorry for the wrong picture.

    I modified the picture of hardware configuration as below,

    > Use Rasberry Pi HDMI output(resolution is 1920 x 1080)

    >  Use NB HDMI output (output resolution is 1280 x 720).

    and have a question before all.

    As I stated my question as below,

    1. Use Rasberry Pi HDMI output(resolution is 1920 x 1080)

    Why doese this hardware configuration make the no connection?

    I just connect the noraml configuration.

    Because this issue leads to  the setting including EDID setting that can't be executed, and even you click the item, such as pattern generator, register... by myself.

    Please help to clarify this issue at first.

  • In reply to Bryan Kahler:

    Dear Bryan,

    1. How do I verifiy the setting of Timing source being saved into DS90UB949? Because I just click "Apply" and no idea save of not.

    2. Are there any documents to help to clarify USB2ANY issue?

    3. How to save the changed DS90UB949 timing source and EDID? Because I turn power off/on our TX/RX board (DS90UB949/948). The settings will be back to default.

    I set as below, and our LCD panel can't display normally but full black.

    DS90UB948, still Mode_sel0 = 1.275V

    register, 0x37 reading as below,

    and the settings of Timing source follows our LCD panel spec. as below.

    3. I Enable Generator inside DS90UB949. Color bars display normally.

  • In reply to Alvin Lin:

    Hi Alvin,

    Those color bars look great!

    One way to confirm that the timing values being set in the Video pane above are being sent to the device would be by sniffing the i2c bus with a logic analyzer and viewing the resultant output on the display.

    As for persistence with the raspberry pi, you may create a custom HDMI mode on the raspberry pi with the proper timing information.  The raspberry pi will need to be modified to use this mode on device boot up.

    The Raspberry PI Foundation has some information on their website with respect to custom HDMI modes, found here: https://www.raspberrypi.org/documentation/configuration/hdmi-config.md

    Please let me know if any issues persist in bring up.

    Sincerely,
    Bryan Kahler

  • In reply to Bryan Kahler:

    Dear Bryan,

    Question:

    1. Is the following register 0x37 I provided you as last response correct?

    2. I try to connect HDMI source from HDMI video pattern generator "Chroma 22294", but ALP shows as below,.

    What situation will the ALP recognizes the linked Deserializer and video source?

    Because I think ALP doing work well and can modify other setting such as pattern generator, it is decided as linked Deserializer is OK.

     

  • In reply to Alvin Lin:

    Hi Alvin,

    Are you experiencing a drop out of the 948 when connecting the HDMI Source?  Was the 948 seen over the backchannel previously?

    As shown in the screenshot above, ALP does not currently detect a link and/or the 948.  Are you able to generate a test pattern with the 949 connected to the 948+display in this state?  With HDMI source connected?  With HDMI source removed?

    Sincerely,
    Bryan Kahler

  • In reply to Bryan Kahler:

    Hi Alvin,

    Are you still experiencing this issue?  If so. is there an update with respect to the questions posed above?

    Sincerely,
    Bryan Kahler

  • In reply to Bryan Kahler:

    Dear Bryan,

    I should clarify the issue by the step for you.

    As Nov 27, 2019 7:09 AM I asked you,

    Question1.>

    I want to ask that I set the correct EDID (Internal timing) corresponing to our LCD panel spec.

    Can I check the modified EDID (Internal timing) being certainly saved in  DS90UB949 by reading register  0x37 ?

    Question2.>

    I want to ask applying HDMI video pattern generator "Chroma 22294", and "Chroma 22294"  has generated a HDMI pattern corresponding to our LCD panel spec into our DS90UB949. The hardware connection as below picture.

    Will this way make ALP tool detect abnormaly? Because as I showed you the picture. Link status all detect "No".

  • In reply to Alvin Lin:

    Hi SHH,

    1a) Please confirm the proper EDID setting with the display manufacturer.  This isn't a standard proprietary to TI.

    1b) On the 949, register 0x37 is CLK_CLEAN_STS and isn't directly related to EDID.  Please read register 0x48 APB_CTL and will allow you to read the APB, however, this is may only be helpful if you're loading the EDID into the SRAM of the device.

    Is the display changing or static?  Is EEPROM with EDID on the display or not?  If the display is not changing and/or the EDID is not available on the display/not known to be proper, it may be easier to set the timing parameters with the SOC.  This is discussed on the raspberry pi site linked above.

    2) The HDMI should not affect the ALP, but after connecting the HDMI pattern generator, please try to power reset the 949 with PDB.  This should fix stability issues seen with ALP.  If issues persist, please let me know.

    Sincerely,
    Bryan Kahler

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.