TLV320AIC3100: After ~1 hour, All Microphone Input Is Lost, Replaced with Noise

GenericEE

Part Number: TLV320AIC3100

Hi Everyone,

We're having a problem with our audio codec (TLV320AIC3100) where it reading analog input correctly after about an hour or so. We have the codec reading from analog input using the microphone input and converting this analog signal into an I2S signal. The codec works great until it suddenly stops reading analog input and starts instead reading a terrible screeching noise. We have performed a number of tests to try stop the noise including:

Verified that all voltages are in the correct range at startup. The voltage appear very stable, and other parts are powered off the same supplies and don't have problems.
Verified that the analog input is correct using an oscilloscope despite the output being screeching.
Verified that the registers are not being modified or any events occurring by reading the values back repetitively from the I2C port. The problem persists if we disable the I2C readback code.
Tested resetting the codec to verify that resetting the codec stops all sound, so the symptoms are not consistent with a spurious reset.
Verified the problem goes away with a reset of the codec and reconfiguration of the I2C registers (without power cycling).

My team and I are completely stumped on this one. If anyone has experienced anything like it, we would like to know.

Thanks,

GenericEE

over 7 years ago

0 Steve-Wilson over 7 years ago

TI__Mastermind 30210 points

GenericEE,

Can you provide your register configuration? I will need your I2S clock frequencies, data word length and format also. I"ll take a look at the configuration and make sure all is well.

best regards,
-Steve Wilson

0 GenericEE over 7 years ago in reply to Steve-Wilson

Prodigy 40 points

Hi Steve,

Thank you for the quick reply. The WCLK input is 48 kHz, the BCLK is 3.072 MHz, and the MCLK is 12.288 MHz. The format is I2S 24 bit. I've attached a file listing all the commands written to the chip to set the registers (they are listed in order of execution). The ones not listed in the file are left at the default values.

Thanks,
GenericEE

TLV320AIC3100IRHBT_reg.pdf

0 Steve-Wilson over 7 years ago in reply to GenericEE

TI__Mastermind 30210 points

GenericEE,

Looking at your configuration it seems that your AOSR is set to 256. (register 0x14 set to 0x00) your NADC = 1 and your MADC = 2 which means your ADC is trying to sample at 24kHz rather than 48kHz. try changing 0x14 to 0x80. You wont be able to run the ADC with an AOSR of 256 when fs=48kHz, (there is a Maximum frequency limit to ADC_MOD_CLK; See table 7-41 in the datasheet)

best regards,
-Steve wilson

0 GenericEE over 7 years ago in reply to Steve-Wilson

Prodigy 40 points

Hi Steve,

That is an accurate assessment based on the spreadsheet. My colleague and I found this issue a before and fixed it, and I failed to update the spreadsheet correctly. Attached is a new spreadsheet.

Thanks,
GenericEE

7178.TLV320AIC3100IRHBT_reg.pdf

0 Steve-Wilson over 7 years ago in reply to GenericEE

TI__Mastermind 30210 points

GenericEE,

Would you mind reading page 0 register 39 when this happens? I didn't see anything obvious with your configuration.

best regards,
-Steve Wilson

0 GenericEE over 7 years ago in reply to Steve-Wilson

Prodigy 40 points

Hi Steve,

I believe the value was either zero or 8. Is there a specific value that should be targeted (e.g. all zero since we don't want any interrupt flags)? Also, do we have to clear the interrupts?

Thanks,

GenericEE

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TLV320AIC3100: After ~1 hour, All Microphone Input Is Lost, Replaced with Noise