(ADV7611)About I2S freerun

Hi

I have some question about ADV7611.

(1) Is the purpose of setting up the I2S free run mode in ADI described on the data sheet?
If not, could you please tell me purpose of providing I2S free run mode?

(2) Could you please point out if the following flow is not recognized correctly?
・ If HDMI is not connected and set to free run mode, it operates in I2S free run mode.
・ When the HDMI connection is established, it synchronizes with the I2S communication speed of the connected device.
・ I2S communication speed is maintained even if HDMI is removed.
・ If the HDMI is not connected when the power is turned off or reset, it will operate again in free run mode.

Best regards

Kawa

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    •  Analog Employees 
    on Jan 22, 2021 11:59 AM

    Hi Kawa-San,

         Video free run is possible.  Audio free run is not possible i.e I2S free run. There is no audio generator on the device therefore it can not generate audio, it is wholly dependent on the HDMI input to generate audio.

         The best bet is to switch to an external audio source if the video is in free run. Audio is slaved to Video in HDMI. we don't have any reason why a separate free run couldn't be done for Audio"

    If HDMI is not connected and set to free run mode, it operates in I2S free run mode.

       - No its not possible for I2S free run, only video free run is possible.

    When the HDMI connection is established, it synchronizes with the I2S communication speed of the connected device.

       - Yes.

    If the HDMI is not connected when the power is turned off or reset, it will operate again in free run mode.

      If the power is turned off, then the chip cannot be programmable, Please note that " Free Run only works when CP core is enabled ".

    Thanks,

    Poornima

  • Hi 

    Thank you for your reply.

    You may have misunderstood, but the output of I2S also free runs.

    Please confirm.

    It has been confirmed on the evaluation board.

    Why ADV7611 outputs I2S clock even if HDMI is not connected?

    Please tell me the purpose of why I2S is output even if there is no HDMI input.

    Is it possible to change the frequency in free run mode from 9.84MHz?

    In the experiment, I ran the following script without HDMI input, but SCLK was output at 9.84MHz.

    (6_1f_Port_A_1080p_YPrPb_444_in_RGB_444_out_Through_HDMI_VIC_16_31_32.py)

    Best regards

    Kawa

Reply
  • Hi 

    Thank you for your reply.

    You may have misunderstood, but the output of I2S also free runs.

    Please confirm.

    It has been confirmed on the evaluation board.

    Why ADV7611 outputs I2S clock even if HDMI is not connected?

    Please tell me the purpose of why I2S is output even if there is no HDMI input.

    Is it possible to change the frequency in free run mode from 9.84MHz?

    In the experiment, I ran the following script without HDMI input, but SCLK was output at 9.84MHz.

    (6_1f_Port_A_1080p_YPrPb_444_in_RGB_444_out_Through_HDMI_VIC_16_31_32.py)

    Best regards

    Kawa

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