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ADV7842 Auto-Detect

Question asked by Glenn on Feb 4, 2015
Latest reply on Feb 5, 2015 by GuenterL

I am using an ADV7842 wired up to receive both HDMI and analog.  Currently to detect what is hooked up I first check to see if HDMI is available by checking DE filter locked (HDMI map register 0x7[5]) If it is locked I continue on to determine the HDMI resolution by reading several register (lcf, active line width, FCL etc).  If the DE filter is not locked then I check STD1_DVALID_CH1_RAW and go through a similar process for determining resolution.

 

My requirements have changed and now I need to prefer the analog input over the HDMI if they are both hooked up. However, just switching the order of operations above does not get me all the way because then if only HDMI is hooked up then I get false positives for analog because STD1_DVALID_CH!_RAW toggles between 0 and 1 in this case.

 

Is there a better way to reliably detect when an analog input is present?

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