X-NUCLEO-CCA02M1 Expansion sample program problem

[Muneeb khan]

Posted on January 08, 2017 at 07:42

I have got a strange problem with X-NUCLEO-CCA02M1 expansion board interfacing with NUCLEO-L476RG. I have followed

https://my.st.com/content/ccc/resource/sales_and_marketing/presentation/product_presentation/d3/44/de/b9/33/a0/4e/25/x-nucleo-cca02m1_quick_start_guide.pdf/files/x-nucleo-cca02m1_quick_start_guide.pdf/jcr:content/translations/en.x-nucleo-cca02m1_quick_start_guide.pdf

quick start guide to test the functionality of MEMS mic through the audacity(v2.1.2) software as mentioned in  doc. I have loaded the test binaries to the X-NUCLEO-L476RG and I am able to get the device recognized as �STM32 AUDIO Streaming in FS Mode� both in my device manager and Audacity software�s microphone list. Now when I start recording in Audacity I get random signals not even close to a normal sound waveform. I have also attached the screenshot of what I am getting along with waveforms of sound I recorded with my internal mic array. I have very little knowledge of internal programming of the test application but consulting

https://my.st.com/content/ccc/resource/technical/document/user_manual/88/5d/3e/6d/9c/ae/42/de/DM00187403.pdf/files/DM00187403.pdf/jcr:content/translations/en.DM00187403.pdf

Getting started guide section 3.4.2.2 I can confirm the jumper connections on board are exactly same as mentioned in this section. I have checked on two windows based machines one is running windows 10 64-bit and other windows 7 64-bit but results are same. I am looking forward for your guidelines to debug the issue. I am sure there is nothing wrong in compiled binaries as I am getting Audio device recognized, I suspect this could be a hardware issue.#cca02m1-memsmic1 #steval-boards-for-mems-mics

[MCU Support Center]

Posted on January 11, 2017 at 10:10

Hello  Muneeb Khan,

the STM32L4  you are adopting is equipped with a peripheral called DFSDM, that allows to acquire and decimate the microphone PDM streams in hardware; the example firmware for L4 uses exactly this interface, thus the solder bridge configuration to be used in this case is the one depicted in the paragraph 3.4.2.1 (not 3.4.2.2) of the user manual, titled 'Jumper settings for DFSDM-based systems'.

Please let me know if this solves the issue.

Regards

Matteo

[Muneeb khan]

Posted on January 11, 2017 at 10:55

Hi Matteo!

Thanks for your good catch. I just changed solder bridges according to the section 3.4.2.1 to use the DFSDM mode but still there is no response from the mems. I don't have oscilloscope around to check whether DFSDM clock is being generated or propogated to mems mics or not. Any other suggestion would be appreciated. 

Regards

Muneeb Khan