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AD9398 and Sony cameras

Question asked by Timur@Darim on Apr 29, 2011
Latest reply on May 19, 2011 by Timur@Darim

Hello,

 

I ran into a problem with AD9398 chip and I was wondering if somone could help me out with it.

Here it is,

 

 

I am having problem with SONY (HVR-HD1000J) camera as source for my HDMI capture board

During connection to the AD9398 HDMI receiver, SONY camera starts to continiously read EDID in a loop.

As a result AD9398 cannot properly detect format of the input signal.

Our other developers have ran into a similar problem with a diffierent Sony camera.

I have tried several other cameras (JVC, Panasonic), all of them work fine with the chip.

 

We also have another device with HMDI input but it uses ADV7441 to do processing of video signal.

With ADV7441 this particular Sony camera works perfectly. Both devices have same EDID. Hence we figured that the problem could be the ROM that contains the EDID. ADV7441 has an internal ROM that stores its EDID while AD9398 does not, so we are forced to use external one. In turn we tried using AD9398 with EDID stored in ADV7441 internal ROM that did not work, the problem persisted.

 

After extensive trial and errors we think that the problem is TMDS clock interface.

During our experiments we noticed that if we cut TMDS off completely, our other cameras still read EDID correctly despite the absence of TMDS signals. Whilst with Sony camera I2C wires are silent when HDMI is connected and TMDS signals are cut off.

 

Is there some physical difference in the TDMS interface between AD9398 and ADV7441A?

Maybe suggest what the problem could be.

 

 

Thank you.

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