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ADV7610: Removing vertical blanking period completely


Hello,

I've connected an ADV7610 to a 720p video source. It is sending out a very nice YCbCr 16 bit stream to a processor, that is being captured relatively well. Video is fine, it's just shifted to the bottom of 20 pixels. Those 20 pixels are the vertical blanking period: the processor receiving the YCbCr input is ignoring the low data enable pin (that is working correctly), so data is saved starting from the blanking period (that I checked with a scope is indeed 20 lines).

I've tried to change the START_VS register, that allows for a reduction in the vertical blanking period, but I cannot reduce it to zero since that the adjustment is limited to +- 7 pixels.

Is there any other way to reduce or eliminate the vertical blanking period?

Thank You.

on Jul 26, 2016 3:02 PM

The padding is really set by the source and how it interprets the EDID.  You cannot really decrease the timing since this would change the format which the ADV7610 cannot do.

You change the output synchronization signal positioning a bit but the overall timing must stay the same.  Check out Figure 52 in the ADV7612 hardware manual.