AnsweredAssumed Answered

ADV7125 ->VGA (Monitor) Problem [with Linux]

Question asked by HaoringPP on Dec 3, 2017
Latest reply on Dec 4, 2017 by HaoringPP

Hello Every one.


I'm using imx6 Dual CPU with ADV7125 and I working on the linux. 

I wanna set to screen output 640x480 60Hz to general PC monitor.


I successed some Image output on the Monitor but it looks like 

timing is not stable .


Here is my circuit diagram : 


My Current Timing is : 

"640x480", // name 
   60,       // refresh
   640,       // xres
   480,       // yres

   39721,       // pixclock

   16,             // left margin (HBP) Back Porch
   48,             // right margin (HFP) Front Porch

   2,                // upper margin (VBP) Back Porch
   25,             // lower margin (VFP) Front Porch

   96,          // Hsync Length
   2,             // VSync Length

   FB_SYNC_CLK_LAT_FALL,          // Sync


Actually, when I googling to 640x480 60Hz 's industry standard's value is this :

but When I changed some data like upper Data, it's result is more stable .. 



I tested this Image : 640x480 size and Each 255 value of Red , Green, Blue Color and totally white area. 


But this image's output is : 




Picture is no good but to explain it : 

Each of Red Blue color is little bit covered green and white. it looks like gradation. 

But Red and Blue's border line and green and white's border line is very clear and perfect. 


This whole size's ratio is Good. (right, left, upper, lower's end of outline is clear. )


I tested anther resolution and timing and pixel clock, 

But it's output is always similar. 


Size and  position was changed, but Horizontal's problem (RED and BLUE is covered GREEN and WHITE)

I think that this symptom is more remarkable at left top and left bottom.


How Can I fix this problem? 


Actually, at first, ADV7125's "BLANK" pin was not connected with CPU. 

So my H/W Engineer connected it with CPU, then left border line was more clear than before.


But, "RED and BLUE is covered GREEN and WHITE" this problem is not changed anything.

What do experienced you guys think of this problem? 


Is this Timing's problem? or Should I study to anther way?