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About the PCM1864 default value

yubin he
Prodigy 40 points


Dear Sir,

  Hello,  Could you tell me the default of the listing:

  Analog PGA = 0dB , I can find it in datasheet.

  Digital PGA  = 0dB , I can find it in datasheet.

  MIXER PGA = 0dB?

  I read the Table 24. Virtual 24bit DSP Coefficient Registers, but there is no default about the mixer for erey channel.

  Thanks you.

  • 0
    TI__Mastermind 28020 points
    Hi,

    The default value for the mixer will be 0 dB for the corresponding input to the ADC control in the mixer, and the rest of the inputs will be muted (-120 dB). For example:

    For a 4 ADC part:
    Mixer 1:
    CH1L : 0 dB
    CH1R : -120 dB
    CH2L : -120 dB
    CH2R : -120 dB
    I2SL : -120 dB
    I2SR : -120 dB

    Mixer 2:
    CH1L : -120 dB
    CH1R : 0 dB
    CH2L : -120 dB
    CH2R : -120 dB
    I2SL : -120 dB
    I2SR : -120 dB

    etc..

    Justin
  • 0 in reply to Justin Bohr
    TI__Intellectual 1060 points

    Justin,

    Follow this question, how can I modify those register you mention??

    I can see them in PPC2 GUI, but don;t see how to modify in datasheet.

    Marco

  • 0 in reply to Marco Hsieh
    TI__Mastermind 28020 points
    Hi Marco,

    The mixer is controlled in the DSP, and therefore you must write to DSP coefficients to change these settings. Please look at section 14.3 Programming DSP Coefficients in the data sheet for more information. You can also enable logging by checking the check box in the lower right hand of the GUI, and open the log by hitting view log. Then make a change in the GUI to the mixer volume. Then hit refresh in the log window. You will then see the writes the GUI made to change that value.

    Justin