Hey ST Community,I'm currently trying out the CCA02M2 MEMS microphone board on a NUCLEO-L476RG, using firmware compiled from X-CUBE-MEMSMIC1.The microphones work, but the signal seems to have some heavy filtering. For example:If I record with Audacity and snap/tap near the mic, I don’t see any response.If I play a frequency sweep from my laptop, it only gets recorded when I’m also speaking, but not if the sweep is played alone.This makes me think there’s a strong filter or noise suppression enabled by default. Where in the firmware should I look to disable these filters? Is it controlled by the PDM2PCM library, or another stage in the middleware?Thanks in advance for any guidance!

Visitor II

Question

Filltering on CCA02M2

Hey ST Community,

I'm currently trying out the CCA02M2 MEMS microphone board on a NUCLEO-L476RG, using firmware compiled from X-CUBE-MEMSMIC1.

The microphones work, but the signal seems to have some heavy filtering. For example:

If I record with Audacity and snap/tap near the mic, I don’t see any response.
If I play a frequency sweep from my laptop, it only gets recorded when I’m also speaking, but not if the sweep is played alone.

This makes me think there’s a strong filter or noise suppression enabled by default.

Where in the firmware should I look to disable these filters? Is it controlled by the PDM2PCM library, or another stage in the middleware?

Thanks in advance for any guidance!

This topic has been closed for replies.