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ADV7343 Test Pattern Issue

Question asked by ranaya on Jan 4, 2017
Latest reply on Feb 8, 2017 by ranaya

Hi All, We're using ADV7343 video encoder to convert 24bit RGB video to a single ended CVBS signal. For testing first we generated the test patterns as per the data sheet by successfully writing I2C data. But the LCD display at the other end does not have a sign of the video signal (nor for 24bit RGB signal). I'm pretty sure that the I2C writing and register settings are okay, specifically the following addresses loaded with the bold color values :

 

0x17 --> 0x02

0x00 --> 0xFC

0x82 --> 0xC9

0x84 --> 0x40

 

The retrieved CVBS signal from DAC4 (low drive) for the test pattern is shown below :

And the schematic we use is attached herewith. A 27MHz of clock signal is fed to the CLKIN_A of the encoder !

 

What could cause this issue ? I read somewhere that a termination resistor has been used to workaround a similar issue. Any suggestions would be appreciated !

 

Thanks in Advance

Anuradha

 

PS: More to this, I checked a BOSCAM with the same LCD (that's SEETEC) through CVBS. The screen displays the camera input without any issue. 

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