DEM-PCM2912AEVM: Plugging in an input mic source does not work

Hi Alex,

Can you share the script you're using to configure the device? Also does windows recognize the codec as an audio device?

Best regards,

Jeff McPherson

Hey! So I'm not sure if I'm missing out on some setting up stuff, but what is the script you're referring to? And when I plug the codec into my PC with a mic plugged into it, it does recognize it in the sound settings on Windows but when I speak into the mic, the volume bar doesn't move and it is not picking up any audio. Also when I plug the mic in, the red LED on the codec flashes a few times before going dim again.

Hi Alex,

Disregard my statement on the script. I didn't realize this is a USB stick EVM. I assume you've read the user guide? https://www.ti.com/lit/ug/sbau141/sbau141.pdf?ts=1677538309451&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FDEM-PCM2912AEVM

If not it contains steps to set up the device correctly. The red LED is a mute indicator. Also try toggling SW1, the mute switch.

Best regards,

Jeff McPherson

Hey, yes I've read the user guide. I've tried toggling the mute switch. It either shows a solid red LED or a blinking red LED and neither is unmuting the mic (assuming the mic is muted). I've read the user guide as well and no luck :/

Hi,

The REC LED should turns on when you are recording and PLAY LED turns on when you run the playback as shown below.

Regards.

Hmmm yea no luck, the red light blinks when I switch the mute switch, and then is solid red if I switch the mute switch the other way. The mic is still not playing. I've tried plugging in different mics too.

Hello Alex,

Is it possible to see a picture of your test setup? I assume this is not the case, but it was brought to our attention that the figures in the user guide have flipped the labels in the for mic and headphones as per this related post: (+) DEM-PCM2912AEVM: Connection of J1 and J2 - Audio forum - Audio - TI E2E support forums. Please verify that this is not causing your issue.

Best,
Andrew

Here is the setup. I've tried switching the microphone between J1 and J2 and it still doesn't work. I've also tried this with 3 different mics.

Alex,

Since you have tried both jacks as a mic input and neither have worked, please confirm the play back feature of the EVM the green LED should flash as playback is happening.

-Andrew

Yes it flashes green when playback is happening.

Alex,

It appears that the EVM you are using is an older version and as a result we are having trouble replicating your issue (related post: DEM-PCM2912AEVM). 

On the EVM version we are using here, I noticed that the output of the mic is very quiet without the PREAMP enabled. Please try enabling the preamp using the dip switch '3:PREAMP' on your board.

Also, please confirm that the USB audio CODEC is the default device in both the playback and recoding tabs of the Windows Control Panel sound settings. Please check the microphone gain in the levels tab of the Microphone tab as well.

Best,
Andrew

Hey, so I turned the dip switches on and still no luck. I checked the default devices in the playback and recording tabs and also no luck. The microphone is set to max gain aswell.

Quick question though, for the dip switch, on is switching it to the right correct?

Hello Alex,

That sounds correct, but since we do not have the EVM and cannot test it ourselves, please try a both positions.

Is it okay to reach out over email so we can talk about possibly replacing this EVM with a new one? I think we are as far as we can go with troubleshooting this issue.

Best,
Andrew 

Hey,

Yeah I tried all possible positions with the dip switch.

Yes you may reach out over email for a replacement.

Thanks

Ok,

I will go ahead and close this thread for now. I will send an email out shortly.