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ADV7181D, about data output during the blanking period.

Category: Datasheet/Specs
Product Number: ADV7181D

Hi,

I have a question about data output of ADV7181D during the blanking period.
Some devices (device A) output the Data 0 signal during the blanking period, but others (device B) don't output Data 0 signal during the blanking period.
* Please see the attached file for more details.

[Question]
- Is it normal for the ADV7181D to output Data 0 during the blanking period?

Could you answer by May 19th?

Regards,
Gattu

Parents Reply Children
  • Hi,

    Is it normal for the ADV7181D to output Data 0 during the blanking period ?

       YES, in blanking period ancillary data will be output in BT.656 stream.

      Generally VBI Data Processor (VDP) of the ADV7181D is capable of slicing multiple VBI data standards on SD video. The VDP decodes the VBI data on the incoming CVBS/YC or YUV data processed by the SDP core. The VDP cannot decode VBI data on the YUV data processed through the CP core. The decoded results are available as ancillary data in output '656' data stream.

      This Ancillary data packets are used to transmit information (such as digital audio, closed captioning, and teletext data) during the blanking intervals.

     Note: During horizontal blanking, ancillary data may be transmitted in the interval between the EAV and SAV sequences. During vertical blanking, ancillary data may be transmitted in the interval between the SAV and EAV sequences. Multiple ancillary packets may be present in a horizontal or vertical blanking interval, but they must be contiguous with each other.

    Thanks,

    Poornima

  • Hi,

    No data is input to the ADV7181D during the blanking period.
    Therefore, device B does not output data 0 during the blanking period.

    But device A outputs data 0 despite the same conditions.
    Is this behavior correct or not?

    Regards,
    Gattu

  • Hi,

      Depending upon the source, the ancillary data will be present.

      Please let us know, Have you connected the source to device B which is connected to device A ?

    Thanks,

    Poornima

  • Hi,

    Yes, the source is same both device A and device B.

    Regards,
    Gattu

  • Hi,

      Please share us the connection setup between device A and device B.

    Thanks,

    Poornima

  • Hi,

    >Yes, the source is same both device A and device B.
    It means the input source(CVBS) is same.


    The device A and device B are mounted on different board. (One ADV7181D is mounted on the board)

    Do you need schematic? If yes, can I share it on local e-mail?

    Regards,
    Gattu

  • Hi,

    Could you please check register "0x62" and check whether "ADF_ENABLE" bit is enabled or disabled between device A & B. 

       ADF_ENABLE (VDP), Address 0x62, [7], User Sub Map ( This bit enables ancillary data output through 656 stream ). If 0 Disable insertion of VBI decoded data into ancillary 656 stream. If 1 Enable insertion of VBI decoded data into ancillary 656 stream and the blanking interval normally contains Teletext information.

    Thanks,

    Poornima