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TAS2563: Digital Volume Control issue

Part Number: TAS2563

Tool/software:

Hi Ivan,

We observe that the final PPC file you had shared after implementing the thermal protection (CLS0281MAE-L152_TI-010925.ppc3) has an issue with the Digital Volume Control feature. The speaker output volume does not not change when the DVC gain registers (book 0 page 7 register 0x10-0x13) are altered. 

However, we did not observe this with the older PPC, the one before implementing thermal protection(CLS0281MAE-L152_012924.ppc3).

As this is a critical issue impacting our testing, your prompt support would be greatly appreciated.

Best Regards,

Sriman

  • Hi Sriman,

    I'll double check this on my side and come back to you on Monday.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • Hi Sriman,

    The gain control at Tuning and Audio Processing is setting book 0 page 7 registers 0x10-0x13, you should set the device into SW shutdown before changing these registers, below is an example of the script for 0dB, from the test this is working normally for CLS0281MAE-L152_TI-010925.ppc3. Perhaps you're adding more gain but the protection and other settings are not letting the output go higher.

    w 98 00 00
    w 98 7f 00
    w 98 00 00
    w 98 02 0d 
    w 98 00 00
    w 98 7f 00
    w 98 00 07
    w 98 10 04 00 00 00 
    w 98 00 00
    w 98 7f 00
    w 98 00 00
    w 98 02 00 

    The gain control at Device Control is setting book 0 page 2 registers 0x0c-0x0f, this works the same for ROM mode or Tuning mode.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • Hi Ivan,

    We tried changing the DVC gain in the similar manner, however there is no change in the speaker output volume. The following is the output dBSPL as measured using our audio instrument. 

    Audio dsp.bin Gain dB dBSPL
    1KHz_signal.wav dsp_0925 -10 86.65
    0 86.6
    10 86.4
    15 86.3

    However, changing the playback volume control in Device control (book 0 page 2 registers 0x0c-0x0f), has desired effect on speaker output.

    Even after setting the Device control volume to -10dB, changing the DVC gain does not alter the speaker output (The audio was playing in faint volume, ruling out the "output clipping" case).

  • Hi Sriman,

    What registers do you mean by "DVC gain"? Is it book 0 page 7 registers 0x10-0x13?

    What is your actual purpose? Do you need to change the gain during runtime? Is there amixer or similar driver gain you should use?

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • Yes, by DVC gain, I mean the book 0 page 7 registers 0x10-0x13. We would like to use these registers to set the speaker output volume based on requirements, during runtime. No, we are not using any amixer or driver gain from the host side.

    Regards,

    Sriman

  • Hi Sriman,

    I think you're comparing against snapshot 1 of CLS0281MAE-L152_012924.ppc3, correct? I think if you compared to snapshot 2 instead, you'll have similar results as the new PPC3 file.

    It seems to me your PPC3 file has too much gain overall. There's +12dB in pretty much all the snapshots. Then you also have +12dB make-up gain at the DRC, this means you won't see meaningful difference in gain until you reach more than about -24dB attenuation, and you're testing only down to -10dB.
    The output is not increasing any further as the gain increases due to protection limiter.

    Best regards,
    -Ivan Salazar
    Applications Engineer