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TLV320AIC3254: Random Pop Noise at Beginning and End of Audio on LO Driver

Part Number: TLV320AIC3254
Other Parts Discussed in Thread: TPA3112D1

Hi Team,

My customer is using the TLV320AIC3254 single-ended; LOL is fed into a TPA3112D1 RINP with a 1uF cap and they are not using the HP drivers. They are sometimes getting a pop noise at the beginning and end of audio. They have configured the driver to leave the DAC on and leave the midpoint powered all the time. Is there something else in the CODEC that can cause this random pop? 

Here is their register dump:

No size specified (using byte-data access)

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef

00: 00 00 60 00 03 21 08 00 00 00 00 02 08 00 80 03    ..`.?!?....??.??

10: 88 08 02 08 80 03 88 04 00 00 01 0c 00 01 04 00    ????????..??.??.

20: 00 00 00 00 00 cc 11 00 00 00 00 00 00 00 00 00    .....??.........

30: 00 00 00 00 00 12 02 02 02 00 00 00 00 00 00 d4    .....????......?

40: 00 ec ec 00 0f 38 00 00 00 00 00 ee 10 d8 7e e3    .??.?8.....???~?

50: 00 00 00 00 00 00 00 00 7f 00 00 00 00 00 00 00    ........?.......

60: 7f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ?...............

70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

No size specified (using byte-data access)

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef

00: 01 00 01 00 00 00 00 00 00 0c 08 10 00 00 08 08    ?.?......???..??

10: 40 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00    @@..............

20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

30: 00 00 00 00 40 00 40 40 00 40 00 00 00 00 00 30    ....@.@@.@.....0

40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

No size specified (using byte-data access)

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef

00: 2e 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

10: 00 00 00 00 00 00 00 00 00 00 00 00 7f ff ff 00    ............?...

20: 00 00 00 00 00 00 00 00 7f ff ff 00 00 00 00 00    ........?.......

30: 00 00 00 00 7f f7 00 00 80 09 00 00 7f ef 00 00    ....??..??..??..

40: 00 11 00 00 00 11 00 00 7f de 00 00 00 00 00 00    .?...?..??......

50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

Thanks,

Antonio

  • Hi Antonio,
    My colleague will look into this issue and get back to you. Thanks.

    Best regards,
    Ravi
  • Thanks, Ravi. I am looking forward to their feedback. Here is some additional info from the customer:

    This issue seems to have something to do with the starting and stopping of data transmission via i2s. To check I mixed noise with the data signal and get noise out but only until the i2s bus stops. I also tried just routing noise to the output but this also only seems to work when the i2s bus is active. This makes me think that data is only output if the i2s bus is active. What I wanted to do was mix in a low level noise factor to eliminate the pop when data starts and stops, but it appears that data is only output when data is being transmitted.
  • Hi Antonio,
    Obviously this popping sound is not normal. I'm curious about their driver, as we've had cases in the past where a driver will reconfigure the PLL every time audio is played which causes a brief dropout in the I2S clocks or other similar things. I can't say that is what is happening here of course. But I am curious because there are PLL settings that are not default, however the PLL is off.
    Register dumps are helpful, but they don't convey any intent. Just a snapshot at a given time.

    more info on their setup might be helpful. Are they using an MCLK? if not, are they using the PLL?... etc...

    best regards,
    -Steve Wilson
  • Hi Steve,

    Thanks for your help. The issue seems to happen due to the Linux driver muting the DAC after data transfer is complete. They have updated the driver by giving it access to the external amp shutdown pin to make sure it is off during these transitions.

    I will let you know if they run into any issues.

    Thanks,
    Antonio
  • Antonio,

    Thanks for the update. I'm glad they were able to resolve the popping problem. Please let us know if we can help in any way.
    best regards,
    -Steve