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ADV7842 VGA Detection with HP-840 Laptop

Question asked by rpmarchand Employee on Sep 30, 2016
Latest reply on Sep 30, 2016 by GuenterL



I'm working with the ADV7842 and the part is working otherwise but I am having an issue with a VGA source.  For some background, I am using AIN1:AIN3 for my analog inputs, SYNC1 is connected to the GREEN input and I believe the hardware is correct.  I have tried a multitude of VGA sources, mainly laptops, and they work correctly.  


When I connect this laptop in specific, the HP-840 Elite Book, the ADV7842 will never get the following signals which indicates that the part is not doing measurements:  

   CH1_STDI_DVALID, Addr 44 (CP), Address 0xB1[7] the measurements performed by the sync channel 1 STDI are not    complete

as well the same happens with channel 2.   


All other windows laptops work correctly and detection happens correctly.  


Do you have any insight into what could be done to detect this laptop correctly?  For reference here's a link to the HP Laptop HP EliteBook 840 Notebook PC | HP®