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Linux/TLV320AIC3106: Digital microphone audio very weak

sergios
Prodigy 95 points
Part Number: TLV320AIC3106

Tool/software: Linux

Dear experts

We need to configure a single digital microphone MP45DT02 configured as a left channel with the TLV320AIC3106 codec.
Following the manual (SLAS509F -DECEMBER 2006-REVISED DECEMBER 2014) on page 37 point 11.3.9 Digital Microphone Connectivity says:

"If a digital single mic channel is needed then the corresponding ADC channel should be powered up, and the unused channel should be powered down. When digital microphone is enabled, neither ADC can be used for digitizing analog inputs. Configuring the digital microphone configuration set up is done by writing to Page 0, Register 107, bits D5-D4, and Register 25, bits D5-D4."

Please, do you can tell us what registers we should change in order to configure the CODEC with our microphone MP45DT02?

- Registers for power UP / DOWN the ADC left and right?
- Register 107 values?
- Register 25 values?

The audio recorded with the microphone seems very weak, and other codecs with same digital microphone are working flawlessly.

Best regards,

Sergio

  • 0
    TI__Mastermind 30210 points
    Hello Sergio
    you will also need to configure register 98 and 99.
    all values in hex:

    w 30 08 01 (over sampling of 128)
    w 30 62 A0
    w 30 63 50

    register 25 and 107 can be left at default settings

    best regards,
    -Steve Wilson
  • 0 in reply to Steve-Wilson
    TI__Mastermind 30210 points
    Sergio,

    I have not heard back from you, I hope that my suggestions helped you to resolve your problems. if not please let me know and I'm sure we can resolve your issue promptly.

    best regards,
    -Steve Wilson
  • 0 in reply to Steve-Wilson
    Prodigy 95 points

    Dear Steve

    Thank you for your interest. I did test your suggestion same day, but I'm not sure about where the problem is...

    I can program the registers 8, 99 and 98 as you suggested me, but without luck. The quality of the recorded audio (using digital microphoneI is excelent, but the audio level is very weak, and it should be similar to those microphones on an smartphone. I have to talk very close to the microphone piece to obtain a strong level. Whenever I move away the microphone (let say half meter) the audio is very weak.

    I've tested 3 microphone units on 3 carrier boards and one EVK with the same results.

    Perhaps the microphone is mono and the recording is stereo, therefore I'm losing audio level... there are some way to send same audio to both channels or so?

    best regards,

    Sergio

  • 0 in reply to sergios
    TI__Mastermind 30210 points
    Hi Sergio,

    Do the other codecs you have tried have any digital processing? Also what is the digital mic clock frequency you are using on the other devices?
    The performance of the mic shouldn't be different across different codecs. So something else must be different.

    -Steve
  • 0 in reply to Steve-Wilson
    TI__Mastermind 30210 points
    Hello Sergio,
    I did not hear back from you on this, I know that the AIC3106 works quite well with digital mics so I hope you were able to figure this out. if not please let me know and we can figure out what is going on.

    best regards,
    -Steve Wilson