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ADV7623 SYSTEM_PD bit issue

Question asked by ChrisO on May 16, 2013
Latest reply on May 22, 2013 by GuenterL



I have found new information on my ADV7623 SYSTEM_PD bit issue so I am reposting.


So all this below behaves as expected per the 8.1 section of the ADV7623 Hardware Manual Rev B.:


Connect Sink Cable:

HP_ARC- pin: 2.78 VDC

HPD_STATE bit: HIGH (i.e. the HP_ARC- pin is high so hot plug detected)

RX_SENSE_STATE bit: HIGH (i.e. there is presence of TMDS clock terminations from the sink)


Disconnect Sink Cable:

HP_ARC- pin: 0 VDC

HPD_STATE bit: LOW (i.e. the HP_ARC- pin is low so hot plug NOT detected)

RX_SENSE_STATE bit: LOW (i.e. there is NO presence of TMDS clock terminations from the sink)


All good so far but when I when I attempt to set SYSTEM_PD to 0 (set all circuits of the HDMI transmitter to powered-up) it comes back as 1 (and I don’t get any video on the sink monitor)!  I cannot set SYSTEM_PD to 0.


This is where it gets weird(er). I set HPD_OVERRIDE bit: LOW (HPD overridden) then I can change the SYSTEM_PD to 0 and I get video on the sink monitor!


Please, please, please, any thoughts why this could occur???


Thank you!


- Chris