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DS90UB947-Q1: screen backligh will be flash one time when power on

Betty Guo
Expert 7300 points
Part Number: DS90UB947-Q1

Hi team,

customer use SOC--947--948--screen, they use D_GPIO3 of 948 as backligh controer. when D_GPIO3 is high, backligh will light up.

below is reg setting :

    u8  ti947_reg[] = {0x17,0x4f,0xc2,0x5b,0xc6,0x0d,0x0e,0x1e,0x0f,0x04,0x4f};

    u8  ti947_dat[] = {0x9e,0xc0,0x98,0x23,0x21,0x05,0x33,0x02,0x03,0x90,0x00};

    //////   ti948   //////

    u8 ti948_reg[] = {0x49,0x1d,0x1e,0x34,0x1f,0x41};

    u8 ti948_dat[] = {0xe0,0x05,0x55,0x0a,0x05,0x1f};

after setting, when power on, the screen backligh will be flash one second, attached video. can you help to give suggestions?

issue video.zip

  • 0
    TI__Mastermind 37040 points

    Hi Betty,

    Can you provide me more detail of the issue? I saw the video with the logo splash is on, which I don't see any issue unless you are referring to the vertical line.

    Aaron

  • 0 in reply to Aaron Heng
    TI__Expert 7300 points

    Hi Aaron,

    this issue have been resolved, it because customer wirte two times reg to turn on backligh.

    but, they meet a new problem is some time backligh is off that is the D_GPIO3 is low.

    1. they would like control D_GPIO3, can you give a example code how to control it? 

    2. we would like you to check if below MODE_SEL0 and MODE_SEL1 setting is correct or not?

    In hardware, for 948 MODE_SEL0, the R1=49.9k, R2=30.1k, it is DualOLDI output; MODE_SEL1, the R1 is open, R=-2.2k

    based on above hardware, customer want override the reg, can you give a example how to set 948 and 947 reg to match the hardware. is the followings correct?

    for 948:

    reg 0x23=0x20

    reg 0x49[1:0]=00

    for 947:

    0x5B[7]=0;

    thank you in advance!

  • 0 in reply to Betty Guo
    TI__Mastermind 37040 points

    Hi Betty,

    You can follow the instruction that I posted here, but ignore the 18-bit setting. Regarding on the mode select, you need to provide me the display datasheet so that I can determine which OLDI format.

    Aaron

  • 0 in reply to Aaron Heng
    TI__Expert 7300 points

    Thanks Aaron,

    just to confirm. I see you post the code how to configur D_GPIO, one quesitons is that does it need enable both PORT0 AND PORT1? I know if use D_GPIO, the PORT1 should be set.

    1. Set the register 0x1E = 0x3 to enable both PORT0 and PORT1.
    2. Set the register 0x34 = 0x3 to enable both PORT0 and PORT1.

  • 0 in reply to Betty Guo
    TI__Mastermind 37040 points

    Hi Betty,

    Yes. If you are using the D_GPIO, you need to enable both ports in order to get the D_GPIO.

    Aaron