ADV7180 Problems

Dear ADI Video Team,

We are using ADV7180WBCP32Z to digitize a PAL video. Every now and then, the digitized video loses synchronization and it gets stuck in that case for duration. Please check the attached images. The output of ADV7180 is shown on the  left. We are also sampling the same video simulatenously with a commercial analog video to USB converter by Avermedia. The commercial converter's output doesn't display any such behaviour and it is shown on the right in the attached images. 

We also sometimes see that the video turns all green as shown in the second attached image. Again, with the commercial video converter we don't see any such behaviour. 

Could you suggest what is wrong? Is our video source overloading ADV7180's internal ADC? We used the 36 Ohm and 39 Ohm resistive divider network (Figure 29 in the datasheet) in front of the AIN pin. 

Thanks in advance.

Adnan

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  • 0
    •  Analog Employees 
    on Jun 12, 2019 1:47 PM over 1 year ago

    Hi,

     Have you refer the Recommended settings document for ADV7180 ?

     How do you configure the board either through script or software driver?

     Please crosscheck your i2c configuration with reference script which is available at https://ez.analog.com/video/w/documents/811/adv7180-design-support-files

    Thanks,

    Poornima

  • Hi Poornima,

    Thanks for the quick answer. We weren't aware of any recommended settings. We configured the ADV7180 manually with the following settings:

    {0x00, 0x04}, //AIN3
    
    {0x04, 0x54},
    {0x17, 0x41},
    {0x31, 0x02},
    {0x3D, 0xA2},
    {0x3E, 0x6A},
    {0x3F, 0xA0},
    {0x58, 0x01},
    {0x0E, 0x80},
    {0x55, 0x81},
    {0x0E, 0x00},
    
    //Autodetect enable PAL_B/NTSC/N443
    {0x07, 0x23},
    
    // Figure35 and Figure 40 for BT601 NTSC and PAL
    {0x31, 0x1A},
    {0x32, 0x81},
    {0x33, 0x84},
    {0x34, 0x00},
    {0x35, 0x00},
    {0x36, 0x7D},
    {0x37, 0xA1},
    
    {0xE5, 0x41},
    {0xE6, 0x84},
    {0xE7, 0x06},
    
    {0xE8, 0x41},
    {0xE9, 0x84},
    {0xEA, 0x06}

    Our video source is PAL B and we are using AIN3. 

    Yesterday, we did some trials with register values. We were able to get rid of the problem mostly when we set the following values:

    {0x00, 0x84} //AIN3 and video source set as PAL B/G/H/I/D. Disabled autodetect.
    {0x01, 0x80} //Disable HSYNC and VSYNC processors. This register write had the most effect.

    With these values, problems seem to be gone. We are unsure yet, we just couldn't yet reproduce the cases given in the images in my previous post. We will do some more testing to verify.

    Now my question is: Why would disabling HYSNC and VSYNC processors seems to solve the issues? Will there be any negative consequences of disabling HYSNC and VSYNC processors?

  • +1
    •  Analog Employees 
    on Jun 13, 2019 11:21 AM over 1 year ago in reply to era

    Hi,

    There are some drawbacks to using the fast switch mode,

    1) Autodetection cannot be used. The video format must be manually programmed,So we need to disable auto-detection.
    2) In fast switch mode the ADV7180 is not robust to poor and non-standard video sources. In this case,better we can disable Hsync/Vsync processor as per RSD document.

    Generally Hsync processor is designed to filter incoming HSYNCs that have been corrupted by noise, providing improved performance for video signals with stable time bases but poor SNR.

    Thanks,

    Poornima

Reply
  • +1
    •  Analog Employees 
    on Jun 13, 2019 11:21 AM over 1 year ago in reply to era

    Hi,

    There are some drawbacks to using the fast switch mode,

    1) Autodetection cannot be used. The video format must be manually programmed,So we need to disable auto-detection.
    2) In fast switch mode the ADV7180 is not robust to poor and non-standard video sources. In this case,better we can disable Hsync/Vsync processor as per RSD document.

    Generally Hsync processor is designed to filter incoming HSYNCs that have been corrupted by noise, providing improved performance for video signals with stable time bases but poor SNR.

    Thanks,

    Poornima

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