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ADV7842: SYNC_OUT jitter

Question asked by MattBF on Mar 8, 2017
Latest reply on Mar 17, 2017 by marklgd

Hi

 

On our custom board we use the SYNC_OUT pin as a H-Sync output.
However the H-Sync provided by the SYNC_OUT pin jitters by up to 6 pixel clocks at a 1600x1200@60 resolution.
This jitter problem also occurs on the Advantiv EVAL-ADV7842-7511 Video Evaluation Board.
To get the evalboard running i used the script ":5-5b 1600x1200@60 UXGA RGB in_ 444 24bit H_V_DE HDMI:" from https://ez.analog.com/servlet/JiveServlet/download/1681-19-25176/AVES3_Folder_EVAL-ADV7842-7511.zip.
Based on the settings made by the script i changed the value of IO-Register 0x15 from 0xB0 to 0x90 in order to activate the SYNC_OUT pin.

 

Any clue what causes this pretty huge jitter and how to eliminate or at least reduce it?

 

Regards,
Matt

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