ADV7393 as black burst generator but problem locking to external H/V

I've seen the message: Using ADV7393 as black burst generator

I want to do the same, I'm using slave SD Timing Mode 1 (using HSYNC and Field), connected a 27Mhz clk and left the pixel data P[7:0] connected to GND.

But i have a problem getting the analog video output to frame align on the sync inputs. It is locked to the pulses but it starts random not locked to the Field. I've tried reseting the internal SD timing from the ADV7393 by setting bit7 from register 0x8A.

But then it randomly starts with its frame

Best Regards

Teun

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  • 0
    •  Analog Employees 
    on Jul 6, 2016 6:02 PM over 4 years ago

    Hi,

    Am I correct in saying that you can get the black bar test pattern output from the part, but that initially, for the first frame or so the output timing is incorrect and then corrects itself?

    This would be the expected behavior after reset/power up. It takes the encoder 1-2 frames to lock to the incoming clock and sync signals.

    Regards,

    Paul

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  • 0
    •  Analog Employees 
    on Jul 6, 2016 6:02 PM over 4 years ago

    Hi,

    Am I correct in saying that you can get the black bar test pattern output from the part, but that initially, for the first frame or so the output timing is incorrect and then corrects itself?

    This would be the expected behavior after reset/power up. It takes the encoder 1-2 frames to lock to the incoming clock and sync signals.

    Regards,

    Paul

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