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ADV7612 in DVI receiver mode and pixel repetition

Question asked by CorentinC on Jan 3, 2013
Latest reply on Jan 9, 2013 by CorentinC

We are using ADV7612 in HDMI receiver mode without problem and we try to make it run in DVI mode but we have strange behaviour with pixel repetition in 480i60 and 576i50 video formats.

 

When using it in DVI mode (the EDID is programmed without the HDMI VSDB in CEA extension block and we receive a stream without AVI info frame in the stream) the pixel repetition is not automatically detected in 480i60 and 576i50 modes.

 

When those two interlaced modes are detected, we set the HDMI register 0x41 to the 0x51 value  in order to force the pixel repetition factor x2 manually. This works fine but when we change the video resolution back to a non pixel repeated format (720p60 for example) and set the HDMI register 0x41 back to its default 0x40 value we loose the video output. Looking at the video output clock it seams to be very unstable in frequency.

 

We have to switch the board power off and on the get a clean clock (74.25 MHz) and video output back.

 

All non repeated pixel video formats works fine up to the time we switch to a repeated pixel video format.

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