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ADV7623 TX Not Powering-up

Question asked by ChrisO on May 8, 2013
Latest reply on May 9, 2013 by ChrisO



I have really tried to "do diligence" on this problem but I'm stuck so thought for the first time I would post a question.  Our prototype board is using the ADV7623 -P part (no HDCP) and I am sending all the ADI recommended register configurations via I2C.  All the responses come back fine but once I attempt to turn on the HDMI transmitter  (SYSTEM_PD, TX Main Map, Address 0x41[6]) by setting the bit to 0 it will still be set to 1 when I read the value back.


SYSTEM_PD, TX Main Map, Address 0x41[6]

Power down control for the HDMI transmitter.

     SYSTEM_PD Description

          0 All circuits of the HDMI transmitter are powered-up.

          1 ◄ Power down the HDMI transmitter, except I2C, HPD interrupt and Rx Sense interrupt.


Now I took the I2C lines from my prototype board and connected them to the ADI ADV7623 eval board (making all required disconnections on the ADI eval board as required and keeping the that microcontroller in reset) and my code works.  i.e. I get the free run blue screen on my sink and the SYSTEM_PD bit stays off once I set it.


Do you have any idea what would cause the SYSTEM_PD bit to stay on even when I command it to turn off?  I've triple checked my prototype board hardware and the only difference I can see is I'm using the -P part on my prototype board and the eval board is using the non -P (HDCP) part.


The PWRDNB pin is pulled high via 10k resistor to 3.3 VDC.


Thank you so much!


- Chris