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ADV7182A is connected to NTSC signal, the vsync output has 507 lines, and there are 27 lines of black edge at the top of the image, how to change it to 480 lines? (720x 254,720x253 to 720X240)

Category: Software
Product Number: ADV7182A

ADV7182A is connected to NTSC signal, the vsync output has 507 lines, and there are 27 lines of black edge at the top of the image, how to change it to 480 lines? (720x 254,720x253 to 720X240)

  • Hi,

    Here's the script for CVBS input:
    42 0F 00 ; Exit Power Down Mode [ADV7182 writes begin]
    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 0C ; Enable Pixel & Sync output drivers
    42 04 07 ; Power-up INTRQ, HS & VS pads
    42 13 00 ; Enable INTRQ output driver
    42 17 41 ; select SH1
    42 1D 40 ; Enable LLC output driver
    42 52 CD ; ADI Required Writes [ADV7182 writes finished]
    There needs to be a 2ms wait after your first write '42 0F 80' for the full reset to take effect, do you have this delay in your code?
    Have you observe the same with direct connection ?
     
    And also have you verified with some other Source/Sink ?
    I beleive,you have enabled the ITU-R BT.656-4 standard timing.
     
    By default the ADV718x video decoders receive analog video and output digital video in accordance with the ITU-R BT.656-3 standard.

      If the receiver system is expecting an ITU-R BT.656-4 output from the ADV718x then this can result in 10 lines of black video being output at the top of the screen.

      This generally occurs with NTSC CVBS video inputs but not with PAL CVBS inputs. This is because of difference in the blanking timing between the ITU-R BT.656-3 and ITU-R BT.656-4 standards for digitised NTSC.
    Thanks,
    Varshini K
  • Dear Varshini K:

                            Thank you for your reply;