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Regarding the pixel output - ADV7441a, ADV7842 and ADV7619

Question asked by harshad on Jan 26, 2017
Latest reply on Jan 26, 2017 by GuenterL

Hi all,


I have an application that uses two chips from Analog Devices - ADV7842 and ADV7619. I have a couple of questions regarding the pixel output. 


1) ADV7619 has 48 pins for the video pixel output and ADV7842 has 36 pins for the video pixel output. I have gone through both the datasheets. I understand looking at the Pixel input / output formatting section of the datasheet that depending on the data rate (SDR / DDR), number of bits used to represent the color space ( 8 / 10 / 12 / 16 / 20 / 24 / 30 / 36 ), sub sampling used (4:4:4 / 4:2:2) and the mode, we have different configurations for the pixel output. Now 


     a) Do the various modes represent anything apart from simply the pin which outputs YCbCr or RGB signals ? Does it          have any other advantages to it ?

     b) Do we need to connect all the pixel output pins for displaying a video in the output? As per the datasheet many of the          pins remain in High-Z state. So is it advisable to not connect the pins those are in the high impedance state ?


     c) In the ADV7619 datasheet, I see the table "Special SDR 4:2:2 and 4:4:4 Output Modes for Video with Pixel Clock          Frequencies Above 170 MHz". Do I have to make some changes in the register settings or is the chip designed          to take care of it by itself. 


I am new to this. Any help will be highly appreciated. 


Srivats Iyer