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TLV320AIC3109-Q1: TLV320AIC3109-Q1 troubles with sound recording through mic.

Aleksandr Morozov
Prodigy 120 points
Part Number: TLV320AIC3109-Q1

 

Hello all!

My customer uses audio codec TLV320AIC3109-Q1 + GSM modem EHS5 (datasheet is here).

The modem uses DAI/PCM digital audio interface.

Recently the customer had a problem with clocking of the codec (see e2e thread here) which was successfully solved.

Now the customer is working with microphone and facing with the following problem: sound from the mic which comes to EHS5 through the codec is dirty or absent. It is depend on MICBIAS voltage:

2.5V reference → sound is very noisy

2.0V reference → there is no sound at all

 

We suppose that the reason can be in MICBIAS configuration register. Below you can find codec configuration which used by the customer. Could you please have a lokk and advice what can be wrong.

 

     300000

     300180

     3002AA

     300381

     3004C0

     300500

     300600

     300708

     300800

     3009C0

     300C80

     300E80

     300F76

     301000

     301384

     301940

     301A80

     301BFE

     301C00

     302440         

     302506

     302600

     302900

     302B00    

     303D80

     304109

     304809

     305E82

     306500

     306600    

    

Thanks in advance

 

 

   

  • 0
    TI__Mastermind 30030 points
    Aleksandr,

    in register 0x0F you set the Gain of the ADC PGA to 59dB. There will definitely be a lot of noise if you use 59dB gain.

    Regarding the mic not working at 2V, which microphone are you using?

    best regards,
    -Steve wilson
  • 0 in reply to Steve-Wilson
    Prodigy 120 points

    Hello, Steve!

    I discussed the issue with my customer and got some additional information.

    The customer uses microphone CMA-6542PF (datasheet is here ). Below you can see the codec connection scheme with it.

    Term.1 connect with MIC_P_1

    Term.2 connect with MIC_N_1

    The customer tests the settings in the following way:

    1) Play sound

    2) There is a voice recording from the microphone

    3) Play record

    The sound plays normally, but the recording from mic is not audible or played with strong distortion (depend on gain) or there is no sound at all.

    Also the customer changed value of resistors (R49, R54) and capacitors (C81, C82) in scheme. It did not help.

    He tried a differential and unipolar connection of the mic and it was not successfully.

    Below you can find the last codec configuration which used by the customer. The parameters that customer changed are highlighted in the text with comments.

    Could you please give an advice for this problem?

    300000

           300180

    3002AA

    300381

    3004C0

    300500

           300600

    300718

    300800

    3009C0

           300C00

    300E80

    /*>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>*/

    300F80   /*ADC PGA Gain Control Register*/                                                              

    30130F   /*MIC1P/LINE1P to ADC Control Register*/

           3019C6  /*MICBIAS Control Registe*/

    301A80 /*AGC Control Register A*/

    301B00  /*AGC Control Register B*/

    301C00  /*AGC Control Register C*/

    301000                          

    /*<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<*/

           302580

    302600

           302900

    /*>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>*/

           1302B80

           /*<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<*/

    303D80

    304101

           30448

    304801

    305E82

    306500

    306600

    302BBC

    304109

    304809   /*HPCOM Output Level Control Register*/

           /*>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>*/

    300F7F   /*ADC PGA Gain Control Register*/                                                              

           302B1E   /*DAC Digital Volume Control*/

    Thanks in advance.

  • 0 in reply to Aleksandr Morozov
    TI__Mastermind 30030 points
    Aleksandr,

    make R54 0 ohms. There should not be a resistor there.

    right now the AGC is set up so that there is 0dB of gain. I don't think that this is what your customer has intended.

    revisit register 1B and make sure to put a higher maximum gain in, otherwise no gain will be applied.

    I would also recommend that they not attenuate mic1p in register 0x13.


    what is the MCLK frequency?

    best regards,
    -Steve Wilson