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ADV7611 automute compressed audio not working

Question asked by vstorm on Jan 4, 2016
Latest reply on Jan 20, 2016 by Rob.Analog

Hello,

 

I am using ADV7611 for both uncompressed (PCM) and compressed (AC3) audio via the i2s pins.

 

I can process audio in both modes by checking the CS_DATA PCM mode i2c register and then handling the stream with the correct codec.

 

However, I have an issue when the stream changes from PCM to AC3.  Since the i2c reads are not very fast, I get some compressed audio which is interpreted as PCM.  This causes artifacts.

 

From the documentation, it seems to indicate that I can use the automatic MUTE on adv7611 to resolve this.

 

My plan was to SET the MT_MSK_COMPRS_AUD bit while in PCM audio mode.

     Thus when the stream switches to AC3 it would automatically mute the audio.

Once my application detects this it would set MT_MSK_COMPRS_AUD to 0 which should unmute the audio and we can proceed without the transition artifact.

 

We have implemented this but the MT_MSK_COMPRS_AUD bit does not mute the compressed audio.

   The other registers are set according to the recommendations in UG-180  (audio mute section).  

Is there are restriction on WHEN the MT_MSK_COMPRS_AUD bit can be changed to still be effective?

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