PCM2706C: Line-IN/Microphone from TLV320AIC3204

Jack Lin3

Part Number: PCM2706C
Other Parts Discussed in Thread: PCM2706, TLV320AIC3204,

Hi Sirs,

Below is our application. The Line-OUT function works fine. However Line-IN/Microphone doesn't work.

(CPU-PCIe X1)--> (TUSB7340 -USB2.0)--> (PCM2706C -I2S) --> (TLV320AIC3204 -Line-IN*1 / Line-OUT*1 / Microphone*2 / Headphone*1)

Would you please help advise how to make Line-IN/Microphone work?

over 4 years ago

0 Paul_Frost over 4 years ago

TI__Guru 53163 points

Hi Jack,

The PCM2706 does not support any mic inputs. Are you actually using the PCM2906?

0 Collin Wells over 4 years ago in reply to Paul_Frost

TI__Guru 62475 points

Can you show the connections between the PCM2906 and the TLV320AIC3204? The PCM2906 has an S/PDIF digital in/out capability, but not I2S like shown in your drawing.

0 Jack Lin3 over 4 years ago in reply to Collin Wells

Prodigy 60 points

Hi Paul and Collin,

We do use PCM2706C instead of PCM2906. The Line-IN and Microphone are connected to TLV320AIC3204.

We thought the mic input can go into PCM2706 through I2S interface and then go into CPU from the topology mentioned above.

0 Paul_Frost over 4 years ago in reply to Jack Lin3

TI__Guru 53163 points

Hi Jack,

Sorry for the confusion. Can you find where the Mic input stops working? Please monitor all of the I2S connections - do you have a data on the I2S Data In pin (FUN3 pin)? Is the LRCK, SCK correct as well?

0 Jack Lin3 over 4 years ago in reply to Paul_Frost

Prodigy 60 points

Hi Paul,

We monitored the I2S interface and all of them have signals including data in and out. Both LRCK and SCK have the correct frequency.

0 Paul_Frost over 4 years ago in reply to Jack Lin3

TI__Guru 53163 points

Hi Jack,

I think the issue is caused by confusion over the I2S input functionality. The input pin is not for an ADC input, but rather for external data to be used with the internal DAC. The internal DAC has the option of accepting external I2S rather than the USB data.

Thanks,

Paul

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PCM2706C: Line-IN/Microphone from TLV320AIC3204