How to implement most basic audio input example on FRDM-K66F

[mpbyrne]

I've recently purchased a FRDM-K66F board, primarily because it offers an on-board microphone. My difficulty is in actually using that microphone or even a line-in microphone. Currently, I'm running the sai_interupt_record_playback example with headphones and a mic plugged into the appropriate jacks. I'm expecting to get some output through the headphones, but I just get a clunk sound and maybe a beep and then just air. Are my expectations wrong?

My one and only goal in using this microphone is in logging spectral data. I don't need to record or playback or anything, so I'm really just looking for the simplest possible example of sampling audio input with this board, either via the onboard mic or an external mic. Any help is appreciated. I've been futzing with this all week. 

Thanks, 

- michael

[scott1]

Hello, I also have difficulty using the digital microphone on the FRDM-K66F. I have defined DIG_MIC pre-processor symbol as outlined above, however, the sai example fails to compile with that directive enabled. Is there any other example that may be useful?

[Sebastian_Del_Rio]

Hello Michael, I hope you're doing well,

We are currently working on updating the "sai_interupt_record_playback" example in the SDK, but in the meantime you can use another example called "sai", located under the demo_apps category.

For this example to work, you just need to define the DIG_MIC macro as I explain below:

 

You can enable said macro by going into your project properties, into the Settings tab under C/C++ Build.

On the MCU C Compiler tab, select Preprocessor and you can click con the marked button to add your new macro.

I hope this helps,

Best regards,

Sebastian