AIC3254 and MICBIAS

Emanuele8874

Other Parts Discussed in Thread: TLV320AIC3254, TLV320AIC3254EVM-K

Hi,

I'm developing an expansion board of IGEPv2 using TLV320AIC3254 codec.

We are in a pre-prototyping phase and we are still using TLV320AIC3254EVM-K. We are able to set various configurations for the adc function using alsamixer (routing, pga level and adc level).

We have an issue regarding MICBIAS function.

If MICBIAS is powered down (MICBIAS Configuration Register Page 1 reg 51 bit 6) we have audible audio on our registered files. We noticed also in this configuration, there is a 0.5 volt in micbias pin.

If MICBIAS is powered on, in every possible configurations mode (Output voltage configuration and voltage source power (AVDD or LDOIN)), the registered files are muted.

Microphone is in differential configuration, and is connected to MICBIAS pin through 1K resistor. It is a sonion electret microphone.

The MICBIAS Configuration Register is set in aic32x4_probe function of the TLV320aic32x4.c file driver http://lxr.linux.no/#linux+v3.3.6/sound/soc/codecs/tlv320aic32x4.c#L626

What's wrong?

Thank you

over 13 years ago

0 J- over 13 years ago

TI__Mastermind 46195 points

Emanuel,

I sent a message to you directly.

Regards,

J-

0 Emanuele8874 over 13 years ago in reply to J-

Intellectual 510 points

Hi Arabona,

I've received your "friend request" but nothing about MICBIAS issue.

0 J- over 13 years ago in reply to Emanuele8874

TI__Mastermind 46195 points

Hi,

Since you have the AIC3254EVM-K board, I suggest you start by looking at the differential mic script found in the control software (AIC3254 CS) under 'Typical Configurations > Recording > Differential On-Board Microphone'. The script tab will show you the script.

The required hardware configuration can be found in the device schematic in the EVM User's Guide. There is a table showing all mic jumper configurations in the first schematic page.

Regards,

J-

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AIC3254 and MICBIAS