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ADV7842 Graphics mode

Question asked by Glenn on Apr 20, 2015
Latest reply on Apr 27, 2015 by GuenterL

We are attempting to adjust our VGA input (ADV7842 in graphics mode) to get as good as colors as possible.  We are using the same 24ohm / 51ohm voltage divider values on the VGA inputs that are on the ADV7842 eval board.  I notice that in the ADV7842-VER.5.9c_AVEB.txt scripts that when in VGA mode that the manual gains are used and set like this: 

44 73 EA ; Set manual gain of 0x2A8

44 74 8A ; Set manual gain of 0x2A8

44 75 A2 ; Set manual gain of 0x2A8

44 76 A8 ; Set manual gain of 0x2A8

 

This is provides very over bright results.  Is there a method other than trial and error to pick acceptable gain values?  Is using the manual gains the best method?  I do not get very good results when the manual gain is turned off as well.

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