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ADV7623 TX Not Powering-up


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

  • Without ever touching HPS_OVERRIDE if I unplug the sink cable then I see HPD_STATE 0x42[6] = 0 (Hot Plug Detect inactive) and RX_SENSE_STATE 0x42[5] = 0 (HDMI clock termination not detected).  When I plug my sink cable in then both bits go high so I assume that is a good sign but then when I attempt to set SYSTEM_PD 0x41[6] to 0 (all circuits of the HDMI transmitter are powered-up) it comes back as 1 (power down the HDMI transmitter, except I2C, HPD interrupt and Rx.)   Section 8.1 is very clear to me and my code works if I connect my I2C lines to the evaluation board so I guess there must be something wrong with my circuit.  I think I need a vacation! 

  • Hi ChrisO

    Did you find a solution? we are using ADV8005 which has the same symptom  like your: even hpd_state and rx_sense_state is set, I could not power on hdmi tx by writing 1 to system_pd.


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