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ADV7391 glitch at end of line 3 in square pixel mode

Question asked by StevenStowe on Jul 31, 2014
Latest reply on Aug 5, 2014 by StevenStowe



I'm using an ADV7391 set up to use square pixel mode and I'm seeing a glitch at the end of line three. The glitch only occurs on odd fields and occurs regularly (but not on every odd field)at the end of line three. The data being driven at the input is the same for every frame.


What could be causing this glitch? The pattern can be effected (but not removed) by changing the PLL on/off and changing the DAC1 output from CVBS to Y. The frequency of the oscillations in this glitch are close to the subcarrier frequency (~3.6-3.9MHz). I am using timing mode 1 - slave.


The glitch looks like this:


Zoomed in view:


(the displayed vertical units are off by a factor of 10, the units are actually 100mV/division)



The current setup that I am using is as follows:

0x82: 0xDB

0x83: 0x03

0x84: 0x30

0x86: 0x01

0x8A: 0x0A

0x8C: 0x55

0x8D: 0x55

0x8E: 0x55

0x8F: 0x25