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(ADV7181D)Output color is blurred

Question asked by donadona999s on Sep 1, 2017
Latest reply on Sep 12, 2017 by donadona999s

Hi !

 

I have some question about ADV7181D.

Our customer are using ADV7181D for the automotive rear camera.

  CameraECU => CVBS => ADV7181D => SoC => Monitor

 

And there is a problem.

Camera ECU overlay some kind of 100%black frame to the camera analog image and output with CVBS.

So the CVBS which is connected to ADV7181D include the black frame.

But the black frame looks the color is blurred.

* I want to send all image to you but it includes confidential information so if you want to check more detail

  please contact me directly.

And OEM is saying this is problem.

We checked this at the ADV7181D Eval board but it looks fine.

But our customer captured the ADV7181D bitmap data and it looks that brightness is changing between each lines.

* Again , if you can contact me directly, I can send you the BMP file.

The bright line's RGB code is about R=G=B=34. (ex line 1)

The dark line's RGB code is about R=G=B=6.

It is very difficult to check the CVBS signal because bleeding level is very small.

They bypass the NJM2502A and Emitter follower and connect CVBS direct to CAP in front of ADV7181D but there was no change.

They set "LAGC to manual" and "LMG[11:0] =0" and "CON[7:0] = 110"  then  symptoms were improved but not perfect.

 

Q1)

Do you have any idea for this problem?

Our do you need more information?

We can send you all circuit if you contact me directly.

 

Q2)

Is this ADV7181D performance limit?

I mean , for example, if customer input 100% black to ADV7181D , would RGB data have value error (as I wrote 6~34) occurs to output data?(BT.656)

 

Q3)

Is it possible to freely change LAGC , LMG, CON(SDP) ?

Is it required not to change?

I want to know are these register user register or not.

 

Q4)

Do you think the emitter follower circuit affect to this problem?

I have to check this to my customer again but they said even if they bypass these circuit and connect CVBS to ADV7181D directly , the problem won't change so I think emitter follower circuit is not the reason for this problem.

 

Also our customer have to report to OEM(Very important OEM) and solve about this issue so if you can please help about this as soon as possible.

They have to report this till September 11.

The project will MP November.

 

Best regards

Kawa

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