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DS90UB941AS-Q1: PCLK_DETECT error

Amelie Zheng
Genius 10865 points
Part Number: DS90UB941AS-Q1

Hi Team,

My customer now use 941 (DSI 1920*2*720) and 2*948(1920*720). And found error in 0Ch register D2, PCLK_DETECT  will become 0 and then display is abnormal.

Customer already try to change 0x5D and 0x5E register but still PCLK_DETECT have error.

Could you kindly help to give some advice?

Here are the initialization

{0x0c, 0x01, 0x03, 0},//reset all

{0x0c, 0x01, 0x08, 0},//Disable DSI
{0x0c, 0x1E, 0x01, 0},//Select FPD-Link III Port 0
{0x0c, 0x03, 0x9A, 0},//Enable I2C_PASSTHROUGH, FPD-Link III Port 0
{0x0c, 0x17, 0x9E, 0},
{0x0c, 0x0E, 0x03, 0},
{0x0c, 0x0F, 0x03, 0},
{0x0c, 0x4F, 0x0C, 0},//Set DSI_CONTINUOUS_CLOCK, 4 lanes, DSI Port 0
{0x0c, 0x5B, 0x07, 0},//Force Splitter mode
{0x0c, 0x56, 0x80, 0},//Enable Left/Right 3D processing to allow superframe splitting
{0x0c, 0x32, 0x80, 0},//IMG_LINE_SIZE0 7:0
{0x0c, 0x33, 0x07, 0},//IMG_LINE_SIZE1 12:8
{0x0c, 0x5D, 0x00, 0},

{0x0c, 0x1E, 0x02, 0},//Select FPD-Link III Port 1
{0x0c, 0x03, 0x9A, 0},
{0x0c, 0x17, 0x9E, 0},
{0x0c, 0x4F, 0x0C, 0},//Set DSI_CONTINUOUS_CLOCK, 4 lanes, DSI Port 1
{0x0c, 0x5B, 0x07, 0},//Force Splitter mode
{0x0c, 0x56, 0x80, 0},//Enable Left/Right 3D processing to allow superframe splitting
{0x0c, 0x32, 0x80, 0},//IMG_LINE_SIZE0 7:0
{0x0c, 0x33, 0x07, 0},//IMG_LINE_SIZE1 12:8
{0x0c, 0x5D, 0x00, 0},

{0x0c, 0x1E, 0x01, 0},
{0x0c, 0x36, 0x00, 0},
{0x0c, 0x37, 0x80, 0},
{0x0c, 0x38, 0x7F, 0},//x end 7:0
{0x0c, 0x39, 0x07, 0},//x end 12:8
{0x0c, 0x3A, 0x00, 0},
{0x0c, 0x3B, 0x00, 0},
{0x0c, 0x3C, 0xCF, 0},//y end 7:0
{0x0c, 0x3D, 0x02, 0},//y end 12:8
{0x0c, 0x40, 0x04, 0},
{0x0c, 0x41, 0x05, 0},
{0x0c, 0x42, 0x0C, 0},

{0x0c, 0x1E, 0x02, 0},
{0x0c, 0x36, 0x00, 0},
{0x0c, 0x37, 0x80, 0},
{0x0c, 0x38, 0x7F, 0},//x end 7:0
{0x0c, 0x39, 0x07, 0},//x end 12:8
{0x0c, 0x3A, 0x00, 0},
{0x0c, 0x3B, 0x00, 0},
{0x0c, 0x3C, 0xCF, 0},//y end 7:0
{0x0c, 0x3D, 0x02, 0},//y end 12:8
{0x0c, 0x40, 0x08, 0},
{0x0c, 0x41, 0x05, 0},
{0x0c, 0x42, 0x0C, 0},

{0x0c, 0x30, 0x01, 0},
{0x0c, 0x01, 0x00, 100},

  • 0
    TI__Guru 66810 points

    Hi Amelie, 

    Is this issue happening on both ports, or is only one of the two displays have this issue?

    Can you provide a full register dump of both ports on 941?

    Regards, 

    Logan

  • 0 in reply to Logan Cummins
    Prodigy 80 points

    Hi sir,

    This issue only happened on port1, port0 is normal. We try to change this ds90ub941 chip to another main board,  this issue follow ds941 chip.

    console:/ # i2cdump -f -y 0 0x0c                                               
    No size specified (using byte-data access)
         0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
    00: 1a 00 00 9a 00 00 58 00 00 01 00 00 61 30 00 00    ?..?..X..?..a0..
    10: 00 00 00 8f 00 00 fe 9e 7f 7f 01 00 00 00 02 00    ...?..?????...?.
    20: 0b 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ?.%.....?  ?..?Z
    30: 01 09 80 07 0c 00 00 80 7f 07 00 00 cf 02 81 02    ?????..???..????
    40: 08 05 0c 00 00 00 00 00 00 00 00 00 00 00 00 0c    ???............?
    50: 16 00 00 00 02 10 80 02 02 00 b2 07 07 06 44 00    ?...?????.????D.
    60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
    70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80 00    ..............?.
    80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    c0: 00 00 82 00 38 00 00 60 40 00 00 00 00 02 ff 00    ..?.8..`@....?..
    d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    e0: 00 00 82 00 28 08 00 00 00 00 00 00 00 02 00 00    ..?.(?.......?..
    f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
    console:/ #
    console:/ #
    i2cdetect  i2cdump    i2cget     i2cset
    console:/ # i2cset -f -y 0 0x0c 0x1e 0x01                                      
    console:/ # i2cdump -f -y 0 0x0c                                               
    No size specified (using byte-data access)
         0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
    00: 18 00 00 9a 00 00 58 00 00 01 10 00 67 30 03 03    ?..?..X..??.g0??
    10: 00 00 00 8f 00 00 fe 9e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
    20: 0b 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ?.%.....?  ?..?Z
    30: 01 09 80 07 0c 00 00 80 7f 07 00 00 cf 02 81 02    ?????..???..????
    40: 08 05 0c 00 00 00 00 00 00 00 00 00 00 00 00 0c    ???............?
    50: 16 00 00 00 02 10 80 02 02 00 f9 07 07 06 44 5c    ?...?????.????D\
    60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
    70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80 00    ..............?.
    80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    c0: 00 00 82 00 78 00 00 64 40 00 00 00 00 02 ff 00    ..?.x..d@....?..
    d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
    e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
    f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
    console:/ #

    above is the ds941 register dump, please refer.

    Thanks

  • 0 in reply to hu yisheng
    TI__Guru 66810 points

    Hi Hu/Amelie, 

    Thanks for the additional information. 

    Please allow me some time to look through the registers, I will respond with feedback on Monday. 

    To verify, you are not seeing this across multiple boards, it is only specific to one IC that also has the issue when soldered to another board?

    Regards, 

    Logan

  • 0 in reply to Logan Cummins
    Prodigy 80 points

    Hi sir,

    As so far, we have found  4  of a total of 100 have this issue.

    It is also have this issue when soldered to another normal board.

    Above is our hardware design, and mipi-dsi is 4 channel  output with 540M clk, RGB888 format, display panel  resolution is 1920 * 720 * 60.

    Thanks

  • 0 in reply to hu yisheng
    TI__Guru 66810 points

    Hi Hu, 

    Thank you for the additional information.

    After looking further into this; I have a few further questions below: 

    1. When this issue exists, is it immediately after start-up, or does it operate successfully then eventually assert the PCLK_DETECT error and display becomes abnormal?
      1. Can you verify that the display in port 0 is always normal?
    2. Can you verify the start-up sequence meets our specification in the datasheet or provide a scope shot? Ensure PDB is asserted after the supplies are stable, etc.
    3. I'm seeing some errors on the DPHY/DSI and invalid line length/blanking interval errors (LINE_VID_ERR)

    Lastly, can you also try changing bit 6, field FORCE_CLK_DET of DUAL_CTL2 (0x5C) to 1 on port 1? Does the issue still exist?

    Regards, 

    Logan

  • 0 in reply to Logan Cummins
    Prodigy 80 points

    Hi Logan,

    1. It is immediately after start-up when this issue exist, we add a workaround that re-initialize all registers when check PCLK_DETECT not night.  It is only occur when hardware test normally,  but our customer found this issue.

    a. Yes, display in port 0 is always normal, even remove our workaround function.

    2. I try to operate PDB gpio by console after system already up (make sure mipi-dsi stable), this issue still exists.

       a. echo PDB low.

       b. echo PDB high.

       c. initialize all registers by i2cset tool.

    3. It is also not work that try changing bit 6, field FORCE_CLK_DET of DUAL_CTL2 (0x5C) to 1 on port 1 .

    Could you give me a register initialize list? I think my register list have some problem.

    Thanks

  • 0 in reply to hu yisheng
    TI__Guru 66810 points

    Hi Hu, 

    Thank you for checking that list of items. 

    Please try the following script file: 

    # 3840x720@60 Symmetric Split Example - 2x 1920x720@60

# Video 0 and Video 1 Parameters:
# HACT = 1920
# HFP = 64
# HSYNC = 32
# HBP = 32
# VACT = 720
# VFP = 45
# VSYNC = 8
# VBP = 8
# PCLK = 96MHz 

# DSI Superframe Dimensions:
# HACT = 3840
# HFP = 128
# HSYNC = 64
# HBP = 64
# VACT = 720
# VFP = 45
# VSYNC = 8
# VBP = 8
# PCLK = 192MHz 

# DSI clock = 576MHz
# DSI Lane Speed = 1152Mbps/lane 
# 4 Lanes DSI
# DSI input port 0

import time

UB941AS = 0x18

board.WriteI2C(UB941AS,0x01,0x02) # Reset
time.sleep(0.1)
board.WriteI2C(UB941AS,0x01,0x08) # Disable DSI
board.WriteI2C(UB941AS,0x1E,0x01) # Select port 0

board.WriteI2C(UB941AS,0x4F,0x8C) # 4 Lane Mode continuous clock

board.WriteI2C(UB941AS,0x5B,0x07) # Splitter mode

board.WriteI2C(UB941AS,0x40,0x04) # TSKIP_CNT
board.WriteI2C(UB941AS,0x41,0x05) # TSKIP_CNT
board.WriteI2C(UB941AS,0x42,0x40) # TSKIP_CNT

board.WriteI2C(UB941AS,0x56,0x80) # L/R Pixel Processing
board.WriteI2C(UB941AS,0x32,0x80) # Set 2D Line Size 1920
board.WriteI2C(UB941AS,0x33,0x07) # 

board.WriteI2C(UB941AS,0x1E,0x01) # Select port 0: 1920x720
board.WriteI2C(UB941AS,0x36,0x00)
board.WriteI2C(UB941AS,0x37,0x80) # X Start = 0
board.WriteI2C(UB941AS,0x38,0x7F) 
board.WriteI2C(UB941AS,0x39,0x07) # X Stop = 1919
board.WriteI2C(UB941AS,0x3A,0x00)
board.WriteI2C(UB941AS,0x3B,0x00) # Y Start = 0
board.WriteI2C(UB941AS,0x3C,0xCF)
board.WriteI2C(UB941AS,0x3D,0x02) # Y Stop = 719

board.WriteI2C(UB941AS,0x1E,0x02) # Select port 1: 1920x720
board.WriteI2C(UB941AS,0x36,0x00)
board.WriteI2C(UB941AS,0x37,0x80) # X Start = 0
board.WriteI2C(UB941AS,0x38,0x7F) 
board.WriteI2C(UB941AS,0x39,0x07) # X Stop = 1919
board.WriteI2C(UB941AS,0x3A,0x00)
board.WriteI2C(UB941AS,0x3B,0x00) # Y Start = 0
board.WriteI2C(UB941AS,0x3C,0xCF)
board.WriteI2C(UB941AS,0x3D,0x02) # Y Stop = 719

board.WriteI2C(UB941AS,0x40,0x10) # Init DSI Clock Settings (From Section 10.2 of datasheet)
board.WriteI2C(UB941AS,0x41,0x86) # Init DSI Clock Settings (From Section 10.2 of datasheet)
board.WriteI2C(UB941AS,0x42,0x0A) # Init DSI Clock Settings (From Section 10.2 of datasheet)
board.WriteI2C(UB941AS,0x41,0x94) # Init DSI Clock Settings (From Section 10.2 of datasheet)
board.WriteI2C(UB941AS,0x42,0x0A) # Init DSI Clock Settings (From Section 10.2 of datasheet)

board.WriteI2C(UB941AS,0x01,0x00) #Release DSI

    Regards, 

    Logan

  • 0 in reply to Logan Cummins
    Prodigy 80 points

    Hi Logan,

    Thank you for the script file, I have found the key about this issue, it is that 0x4F bit7 should be set 1.

    when DSI_CONTINUOUS_CLK  be set 1, the issue be fixed.

    Thanks for your support very much.

    Thanks