TLV320AIC3254: ADC Powered Down when AGC is enabled

Hi,

How about the Gain status flag? It seems like the gain/target setting needs to be adjusted.

Regards.

Hi pdjuandi,

The gain status flag is return 0xFe;

BR

Trevor

I meant the gain status in register 36.

Hi pdjuandi,

It return 0;

0: Gain in Right AGC is not saturated

BR

Trevor

Do you see it powered down if AGC is disabled? I don't see how ADC is powered down by volume changed in the source. 

Is the ADC chain/path really shutdown?

Hi pdjuandi,

We don't see the ADC powered down with AGC disabled. 

We did some experiments on the CC3200AUDBOOST Evaluation board | TI.com .

It doesn't appear on the Microphone path, it only appears on the Line-in path.

You also could refer our pervious thread(TLV320AIC3254: Update filter coefficients on the fly when AGC is enabled - Audio forum - Audio - TI E2E support forums):

Step 3  (ADC Flag Register = 0x46)

Step 4  Generate loud sound(simple pulse) into ADC,  (ADC Flag Register = 0x44)

Step 5 Remove the pulse signal (ADC Flag Register = 0x46)

Regarding ADC powered down issue will disappear when we decrease the input voluome(for example ： win 10 volume control) .

BR

Trevor

Hi,

When ADC powered down, what is register 81 read back values? AGC should not disable ADC unless it's written to power it down.

Previous thread does not show ADC powered down - is this new?

Regards.

Hi pdjuandi,

Regarding previous thread, our question is how to update the filter coefficients on the fly when AGC is enabled.

The first things is we can only update the filter coefficients after ADC power-up.

You could check the previous steps(we only enable the right channel):

Step 3  (ADC Flag Register = 0x46)  ->   in this step, the right ADC is powered up

Step 4  Generate loud sound(simple pulse) into ADC,  (ADC Flag Register = 0x44)

-> in this step, the right ADC is powered down

Step 5 Remove the pulse signal (ADC Flag Register = 0x46)

-> in this step, the right ADC is powered up

So, Diljith didn't answer our question !

We will provide the status of register 81 later.

BR

Trevor

Hi,

Per this apps. note https://www.ti.com/lit/an/slaa425d/slaa425d.pdf?ts=1651861238063&ref_url=https%253A%252F%252Fe2e.ti.com%252F AIC3254 is a non-adaptive codec family therefore you can't change the coefficient on the fly.

Regards.

Hi pdjuandi,

Regarding updating filter coefficient, we did it on the following thread:

https://e2e.ti.com/support/audio-group/audio/f/audio-forum/922969/tlv320aic3254-can-t-change-filter-coefficients

When ADC powered down, what is register 81 read back values? AGC should not disable ADC unless it's written to power it down.

>>>>>>>>>>>>>>>>>>>>>>>>

The Register 81 returns 0xC0 when ADC powered down.

BR

Trevor 

You were not able to update the coefficients in previous thread also - correct?

This ADC power down status is strange and I'm checking internally if there's any mechanism that can power down ADC path with AGC enabled. You did not see this in the previous thread.

Hi pdjuandi,

Thanks for your suggestions.

BR

Trevor