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Color-bar test pattern broken from ADV7280-M

Category: Hardware
Product Number: ADV7280-M
Software Version: raspberry pi lite bullseye rpi-5.15.y

I have design custom board for raspberry pi board to support analog camera image.

as result i have get broken color-bar test pattern.

Is there any check point to resolve this issue?

Thanks for reply

(1) color-bar test pattern output

(2) used i2c script

* I used "Color Bars 480i MIPI Out" from ADV7280M_Cust-VER.4.1.txt

42 0F 00 ; Exit Power Down Mode
42 0E 00 ; Enter User Sub Map
42 0C 37 ; Force Free-run mode
42 02 54 ; Force standard to NTSC-M
42 14 11 ; Set Free-run pattern to color bars
42 03 4E ; ADI Required Write
42 04 57 ; Power-up INTRQ pin
42 13 00 ; Enable INTRQ output driver
42 17 41 ; select SH1
42 1D C0 ; Tri-State LLC output driver
42 52 CD ; ADI Required Write
42 80 51 ; ADI Required Write
42 81 51 ; ADI Required Write
42 82 68 ; ADI Required Write
42 FE 88 ; Set CSI Map Address
88 DE 02 ; Power up MIPI D-PHY
88 D2 F7 ; ADI Required Write
88 D8 65 ; ADI Required Write
88 E0 09 ; ADI Required Write
88 2C 00 ; ADI Required Write
88 00 00 ; Power up MIPI CSI-2 Tx

(3) schematic



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[edited by: YigeunLee at 8:04 AM (GMT -5) on 27 Jan 2023]
  • Hi,

    Please do check whether you are using a crystal or an oscillator. A crystal requires a voltage from the ADV7280-M to operate while an oscillator is powered externally. An oscillator output should be fed into the VrefN pin of the ADV7280-M and an additional I2C write is needed see How Do I Use an External Oscillator to Clock the ADV728x ?

    Note that If a crystal is used then it will not oscillate until the ADV7280-M has been programmed out of power down mode.

    Please check that the crystal / oscillator is outputting 28.63636MHz.

    Thanks,

    Poornima

  • Hi !

    Thanks for reply my question

    I used crystal(*) and checked operating signal that seems to be no issue.

    Vref pins is working when i try get camera image on raspberry pi console. (ex command: cat /dev/video0)

    As a result, I can't find issue on hardware part.

    Do you have any idea of point that need check?

    Sincerely 

    Yigeun Lee

    * crystal part.no: ECS-286.3-20-30Q-EN-TR

    Fig.1 crystal signal from oscilloscope

  • Hi !

    I resolved previous issue but another issue appeared.

    Input image from camera is very dark.

    I have checked color bar test pattern and it is fine.

    Is there any checkpoint ?

    Sincerely 

    Yigeun Lee

    Fig 1. image from camera

  • Hi,

     Please check that the FSC_lock bit (User Map register 0x10 bit[2]) is high. This bit indicates that the ADV7280 has locked correctly to the color subcarrier.

     Also you can disable or change the threshold for the color kill function. The color kill function forces the ADV7280
    into black and white or gray output if the amplitude of the color subcarrier is too small. See the respective bits in the ADV728x hardware manual.

    CKE, Color Kill Enable, Address 0x2B[6]
    CKILLTHR[2:0], Color Kill Threshold, Address 0x3D[6:4]

    Note : ADV728x may not work for poor video signals.  If the color burst is below that percentage of the standard's value then the color will be killed,this will happen due to weak signal. If the color subcarrier is below 14.275mVpp,then the ADV7280 will not be able to lock to the color subcarrier and it will output a black and white image.

    Adaptive contrast enhancement (ACE) block offers improved visual detail by using an algorithm to auto-matically vary the contrast levels to enhance picture detail.

    The ACE function is disabled by default. Please refer Page49 for more details in https://www.analog.com/media/en/technical-documentation/user-guides/ADV7280_7281_7282_7283_UG-637.pdf

    Also Please try manually adjust the Luma AGC monitors & changes in the horizontal sync depth and it adjusts the gain accordingly.   

    Please refer Page 43 in hardware manual at https://www.analog.com/media/en/technical-documentation/user-guides/ADV7280_7281_7282_7283_UG-637.pdf

    Thanks,

    Poornima

  • Hi, thanks for reply

    I checked that FSC_lock bit is 1 (see below fig.1).

    CKE and CKILLTHR are not work for me.

    one of strange thing is that color is fine when i connect to AIN1 directly. (fig.3)

    And color is fine if i change INSEL bit ( 0x09 (Y/C, S-Video)-> 0x02 (CVBS AIN3) ) (fig.5)

    Fig 1. Checking FSC_lock bit

    Fig 2. Signal from AIN1

    Fig 3. Connecting to AIN1 directly

    Fig 4.Image from AIN1

    Fig 5.Changing INSEL bit ( 0x09 (Y/C, S-Video)-> 0x02 (CVBS AIN3) )

  • Hi,

     Please ensure your i2c configuration with below writes,

        For  AIN 1 pin configuration please check the below part in ADV7280M_Cust-VER.4.1.txt

     ##CVBS AUTODETECT##

    :AUTODETECT CVBS Single Ended In Ain 1, MIPI Out:

    delay 10 ;

    42 0F 00 ; Exit Power Down Mode

    42 00 00 ; INSEL = CVBS in on Ain 1

    42 0E 80 ; ADI Required Write

    42 9C 00 ; ADI Required Write

    42 9C FF ; ADI Required Write

    42 0E 00 ; Enter User Sub Map 

    42 03 4E ; ADI Required Write

    42 04 57 ; Power-up INTRQ pin

    42 13 00 ; Enable INTRQ output driver

    42 17 41 ; select SH1

    42 1D C0 ; Tri-State LLC output driver

    42 52 CD ; ADI Required Write

    42 80 51 ; ADI Required Write

    42 81 51 ; ADI Required Write

    42 82 68 ; ADI Required Write

    42 FE 88 ; Set CSI Map Address

    88 DE 02 ; Power up MIPI D-PHY

    88 D2 F7 ; ADI Required Write

    88 D8 65 ; ADI Required Write

    88 E0 09 ; ADI Required Write

    88 2C 00 ; ADI Required Write

    88 00 00 ; Power up MIPI CSI-2 Tx

    End

    Please note that, Default configuration for INSEL register will be on "CVBS input on AIN1" (00000 by default).

     But please note you need to take care with remaining I2c configuration also (i.e You must program the part with I2C), So please compare your configuration with '##02_CVBS SINGLE ENDED AUTODETECT ##'(Autodetect CVBS Single Ended In AIN1) at  7563.ADV7281_CUST-VER.1.4.txt.zip

    Also note that the unused analog input pins (Ain X) of analog devices video decoders can be:

    1) left floating.

    2) connected via a resistor to ground.

    3) connected directly to ground.

    Thanks,

    Poornima