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ADV7619 Audio question


I  have got a problem with the ADV7619 receiving audio. See below the problem description:



We are using a Valens VS100 Rx chip to receive HDBASET content. The output of this chip is then fed into a ADV7619 (via TMDS TX of valens).


Our HDBaseT source is coming from a Quantum data 780E delivering HDMI 19020x1080p60 with audio 48Khz PCM. We are able to get the video correctly out of ADV7619. But there is no audio or there is audio for a brief moment and then the audio disappears.  


I started to investigate this by looking at the ADV7619 data sheet and found  a section/table under “selectable mute conditions). These are controlled by HDMI map registers  0x14, 0x15 and 0x16. We are driving the chip with default settings hence all the selectable mute bits are set. I started by clearing these bits (Ie, not muting under these conditions). This doesn’t seems to have made difference to the audio (still no audio). Note the bits I was clearing are the one documented in “Table 20” of the data sheet.


Interestingly a read of the IO map register 0x65 gave me the value of  0x4E ( 01001110 ).  This indicates that the channel status data is not valid (bit 7) and audio is muted (bit 6).


While I was playing with the selectable mute bits, By accident, I cleared the bits 2 and 3 of the HDMI map register 0x14. And I started hearing audio again. A quick read of the IO map register 0x65 gave me the value of  0x8E (10001110). This indicates that the channel status data is valid (bit 7) and audio is not muted (bit 6).


The problem is that these 2 bits are NOT documented in the data sheet. And we don’t understand why clearing these bits causes the channel status data to go from invalid to valid (hence the audio to mute -> unmute).


Any idea what is my problem might be?

Thank You In Advance!


Parents Reply
  • Hi,

     Here we have verified in our evaluation board. But we could able to hear the audio by with or without clearing bit in 0x14[2:3] register in HDMI map. Similarly,the registers 0x15 and 0x16 also didn't affect with audio.

    Only AUDIO_MUTE 0x1A[4](HDMI Map) may be can force the audio mute.And also one more register HDCP_ONLY_MODE 0x00[6] (HDMI map) related with HDCP which can also affect audio when both registers set it as high.Please crosscheck.