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TLV320ADC6140: Any ways to smoothly update biquads for each channel?

Part Number: TLV320ADC6140
Other Parts Discussed in Thread: PCM1690

Hello,

I am currently using two TLV320ADC6140s for my device, and I want to be able to smoothly modify the biquad coefficents without it sounding choppy and cutting in/out. The ADCs are configured for 4 channels each (8 channels total) at 96 kHz, and I have had success testing different EQ filters based on values I generated from PPC3 software.

Right now, I am powering down the ADCs through the PWR_CFG registers (also disabling inputs/outputs with IN_CH_EN and ASI_OUT_CH_EN). Once the coefficients are written, I add a short delay then power the ADCs back up. I figure this is the safest way to configure the biquads (I use a similar method for changing the input gain, which requires powering down the ADCs according to the datasheet).

However, because I am adding that delay and manually shutting down the ADCs, I can't continuously modify my EQ and get a smooth output. I have tested NOT shutting down the ADCs, but I still hear some choppiness and audio artifacts when trying to modify different parameters on the fly (I'm calculating my biquads locally).

Is there any workaround or solution to this problem? It would be great if I could test different filters by smoothly modifying the input parameters and then hear it without the audio cutting in and out.

Additional details about my setup:

  • 24-bit TDM audio (formatted as 32-bit for interface with my two PCM1690 DACs)
  • 24.576 MHz MCLK frequency
  • DRE and AGC both disabled

Thank you!
Max

  • Hi Max,

    Unfortunately, the biquad coefficients must be written to before powering on the ADC channel as advised by the datasheet:

    My only idea for this testing would be to apply a different biquad to each channel, then test the audio from each channel individually. You could use the DVOL control in CHx_CFG2 to mute the other channels to isolate each biquad output. DVOL can be changed on the fly.

    Best,

    Garret

  • Hello Garret,

    Ok, I understand. Thank you for the reply. Unfortunately, my goal was to have customizable biquads for each channel, so muting probably wouldn't be an option for me. I will continue using it as is, but this was helpful.

    Thank you for the help,
    Max