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TLV320AIC3254: IN1 to headphone output audio root bypassing DSP processing

Takashi Onawa
Genius 13200 points
Part Number: TLV320AIC3254

Hi Team,

I would like to connect the root of TLV320AIC3254EVM as below. In order to compare the performance difference between with DSP and without DSP condition, I would like to bypass DSP block and connect internal ADC to DAC directly but I could not. 

Could you tell me procedure which allows us to connect as below on the GUI? Or Could you share any macros to import the settings?

Regards,

Takashi Onawa

  • 0
    TI__Guru 57800 points

    Hi, Takashi,

    The 'AIC3254 features a loopback option that will connect the ADC output to the DAC input internally. Please Take a look to Page 0 / Register 29, bit D4. In the CS software, this option can be enabled in the Audio Interface Tab of the Clocks/Interface Window as shown below:

    Regarding the device configuration, you need to manually setup the playback or record depending on the typical configuration you used. I am attaching a script that can be used as reference, you can load it with the command-line interface tool of the GUI.

    4062.AIC3254-Recording_Playback.cfg

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    TI__Genius 13200 points
    Hi Diego-san,

    Thanks for your quick response on this.

    I can do it with following procedure.
    [Typical Configurations]
    Recording → Audio Recording Tab → Select "High Performance Stereo Recording(IN1)" and Push "LOAD"

    [Digital Settings]
    Clocks / Interface →　Dividers tab → Push "Program USB Audio Settings" button
    Clocks / Interface →　Audio Interface tab → Check "Digital Loopback"

    [Analog Settings]
    Audio Outputs → Output Routing tab → Headphone Output Routing → check "LDAC_P" and "RDAC_P"
    Audio Outputs → DAC / Line Outputs tab → DAC Output Gain Control → Check "Power"s
    Audio Outputs → Headphone Outputs tab → HP Output Gain Control → Check "Power"s

    I could set the EVM as the following condition
    - Stereo Input from IN1
    - Bypass internally(ADC to DAC)
    - Stereo Output

    Then, I want to import High pass filter to both LADC and RADC.
    Could you tell me how to do it?
    I could write settings for the Right ADC only by belonging to the procedure of capture 7 in the document below.
    But I haven't found the way to write for Left ADC.

    Configure the Coefficients for Digital Biquad Filters in TLV320AIC3xxx Family
    www.ti.com/.../slaa447.pdf

    Regards,
    Takashi Onawa
  • 0 in reply to Takashi Onawa
    TI__Guru 57800 points

    Hi, Takashi-san,

    Thanks for the explanation. With the configuration you followed, the biquads available are set in the DAC side, the default processing block is PRB_P1, which have three biquads available per channel. The location of these biquads is mentioned in Table 2-18 of the Applications Reference guide.  You need to write the biquad coefficients to these locations, please also consider that only Biquads A, B and C are available with the default DAC processing block.

    The code from the mentioned document is only an example of how to configure the Biquads in a generic AIC3xxx device, but you need to adjust the coefficient location for each particular codec.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    TI__Genius 13200 points
    Hi Diego-san,

    Which application note are you referring for Table 2-18?
    There are so many document for this product, so could you please put the link here?

    If I will not make it after reading the Ref guide, I might ask again in another thread.

    Regards,
    Takashi Onawa
  • 0 in reply to Takashi Onawa
    TI__Guru 57800 points

    Hi, Takashi-san,

    The document I mention is effectively the Applications Reference Guide for the 'AIC3254:

    Table 2-18 is located in Page 45 of the document.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer