MSEN state of ADV7625 TX.

Question

Please tell me about the MSEN state of ADV7625 TX. 
 When the MSEN state from the monitor is 0 with a metal wire HDMI cable, MSEN is incorrectly detected as 1 with an HDMI cable with EQ or an optical HDMI cable. 
 Some optical HDMI cables do not cause false detection and have an MSEN of 0. 
 So, my question is, which signal line is MSEN used to check? DDC line? TMDS line? 
 I would like to know how to identify optical HDMI cables that will not cause false positives like metal wires. 
 Best Regards.

DharaniS · Accepted Answer

Hi,

Monitor Sense detects the voltage level on the TMDS lines. When it's ~2.5-3V it means the sink is connected and has the correct termination turned on. The software checks this Monitor Sense bit and can decide to transmit or not. Looks like the video card is doing the same thing. It has to see a valid termination plus have a high HPD to begin transmitting. 
 
 Many sources will not output TMDS unless they see the correct termination on the TMDS lines. First try with another source. Then let's see how you are setting TERM_AUTO bits.

rx_sense_pd should not be applied during the configuration of the HDMI Tx as it disables an oscillator required to complete the configuration of the TMDS output clock channel. It is recommended to use rx_sense_pd when the HDMI Tx has been completely configured. 
 
 Thanks, Dharani S)

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MSEN state of ADV7625 TX.

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