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ADV7611 video stability

Question asked by KaiBTec on Nov 7, 2012
Latest reply on Nov 7, 2012 by GuenterL

Hi!

 

I have a strange effect. I can reproduce the same behavior on the ADV7611 evaluation board as on our own boards.

 

When connecting a HDMI video source with a stable video signal (i.e. no moving/changing parts present) I see a lot of random content when whatching at a single bit of the output stream, i.e. Bit 23 (Red MSB).

 

I triggered my scope with the Vertical sync signal and look with a second channel on contents of the bitstream. Trigger delay was set in a way that I can see the contents of line 100.

 

The signal is more stable with low resolutions, like 800x600. Especially with 1920x1080p the contents start to get more and more random.

 

I tried different kind of HDMI cables and 3 different HDMI sources which all make a stable signal on a TV.

 

The I2c sequence to initialize the adv7611 is takein from here: http://ez.analog.com/thread/9106

When testing with the ADV7611 board I have the same behaviour. In this case I use the initialization which is executed by the on board LPC.

 

Any Ideas how to solve this problem? Are there any i2c registers that can be tweaked to get a stable signal?

 

The HDMI sources are all unencrypted.

 

Best regards,

 

Kai

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