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ADV7604 and 640x480

Question asked by ronak.desai on Sep 23, 2014
Latest reply on Sep 24, 2014 by GuenterL

Hi,

 

We are using ADV7604 to process the Analog signal. We are able to make it working for all resolutions starting from 800x600 and we could make it working.

 

But we are facing a problem with 640x480 resolution only with one particular source. This video source is sending analog signals on standard VGA cable at negative 31.49 Khz Horizontal Sync and negative 59.95 Hz vertical frequencies. Which we confirmed by probing the output signal of the video source.

 

Now, when we provide this input to ADV7604 it detects it as 640x480 and configured following horizontal and vertical timings.

Horizontal front porch : 16

Horizontal back porch : 48

Horizontal sync width : 96

Vertical front porch : 10

Vertical back porch :33

Vertical sync width : 2

Pixel clock : 25.175 MHz

 

With these configurations, when we capture the output of ADV7604 then we are observing that there is half-inch image cut on left side. otherwise everything is proper in terms of picture height, width and color.

 

We tried changing the horizontal back porch and front porch but we can see effect of it only on the right hand side of the picture, meaning only front porch changes are coming into effect but all the time image cut on the left hand side remains same irrespective of back porch value.

 

Please suggest what we can do for this as we have tried almost 14-15 different timing values and we are not getting success in resolving the left side half-inch cut in picture.

 

Thanks,

Ronak

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