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ADV7341 incorrect H&VSync

Question asked by JamieArrow on Nov 6, 2013
Latest reply on Nov 6, 2013 by GuenterL

I’m hoping you can help:

we’re using the ADV7341 in a new product, I have it setup in the G, B, R, CVBS, Luma, Chroma configuration (top row in table 37 of the data sheet) my RGB DACs are all working fine in HD progressive video formats but I’m struggling to get the CVBS output working with SD interlaced.

 

On the scope trace attached you can see my problem – I am generating 720x576i 50 colour bars but it looks like I am getting 2 syncs and colour bursts rather than one. My line timing is 64us (as it should be) so I’m wondering if I am giving the ADV7341 incorrect H&VSync, I am generating all of the signals in an FPGA. At first I tried giving the ADV7341 full H&VSync pulses (ie one VSync lasting several HSync pulses) but the datasheet looks like it shows similar pulse lengths for both (Figure 107 SD Slave Mode 2, PAL).

 

Do you have any suggestions for things I can try to solve this?

 

Thanks in advance

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