TMDSLCDK6748: Reading data from Line and Microphone Input

Carlo

Part Number: TMDSLCDK6748
Other Parts Discussed in Thread: PCM1864

Hi Team,

Good day. Our customer needs to read in data from the line input and the microphone input. He needs to create two buffers, one for line in and one for mic in, to use for some processing algorithms that have written in Matlab and converted to C already. Then, he will need to send data through the line out through a speaker. The customer has the MCASP example running properly and has just been trying to make it works so that it can be altered for his needs.

Do you have any suggestions on how to read data in from both inputs and then send data out? Your assistance is appreciated.

Regards,
Carlo

over 3 years ago

0 Sahin Okur over 3 years ago

TI__Mastermind 27355 points

Hi Carlo,

My colleague who is more familiar with the McASP is out of office until next week. Until then I will try to help as best I can.

From looking at the LCDK schematic, I am not sure the codec can receive input from mic in and line in simultaneously. I see there is only one DOUT signal on the codec. The customer may need to do something such as using the L channel for mic input and the R channel for line input. They may need to reprogram the AIC3106 codec to do this. I would recommend also asking this question on the Audio forum as they would be more familiar with the AIC3106.

I'm also linking some resources below that may help with this.

Processor SDK RTOS Device Drivers - McASP

Training Series - The multichannel audio serial port (McASP) primer

McASP design guide: Tips, tricks and practical examples

E2E - using TLV320AIC3106(Audio codec), How can I "separately" receive and control two signals from two microphones in ccs?

Regards,
Sahin

0 Rahul Prabhu over 3 years ago

TI__Guru** 114920 points

Hi Carlo,

The LCDK board has been designed to get only Line in input and provide Line out using a stereo AIC31x codec. Stereo codec only allow only two channel (left and right) to be input to DSP using the MCASP codec. You may not be able to exercise the MIC Input and line input at the same time. Also note the MICBIAS on the board is not connected so the board doesn`t support providing power to external microphones. Having said that you can use externally powered mic to mic in and try if that works.

You don`t need to modify the configuration for Line out as the output from the system still appears to be stereo line out.

Ideally to make this work you will need a separate serializer pin on the MCASP to get Mic input and a separate MCASP serializer to get line out. We do provide a reference design that shows multi mic input and stereo out using C6747 EVM that can be used as reference. This design uses PCM1864 for mic in and AIC codec for output. Check out the design here:

https://www.ti.com/tool/TIDEP-0099

Regards,

Rahul

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TMDSLCDK6748: Reading data from Line and Microphone Input