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STM32F4-Discovery's Microphone

Question asked by Franch on Nov 4, 2012
Latest reply on Nov 5, 2012 by K A

I want to do a very simple project using FreeRTOS alongside with STM32F4-Discovery. I want to create a task to read from a microphone, another one will filter the mic's data and a final task would output the filtered data to the headphone output.
I decided to start by the input side and, for so, I took a look at the audio playback and record demo that came with the kit.
But it is actually confusing me more than helping.
I wanted to simply get the data from the mic and store it in a buffer. But it seems that I must use the SPI interruption. I wanted to make it simpler than that.
Also, I tried copying waverecorder's functions to my project but I am having a really hard time with the pdm filter. 
The linker always complains that it can't find the functions defined in pdm_filter.h, even though I have added pdm_filter.h and libPDM_filter_IAR.a to my project.

I have looked on the internet and on forums for help, but I couldn't get much of it. Also, the documentation is not clear enough on this aspects.

Thanks in advance