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PDM2PCM example code

kcire L.
Associate III

Hello,

I am trying to understand the PDM2PCM conversion using I2S as the receiving protocol. Does anyone have an easy example for generating a single PCM sample from the PDM data bits? I am having some difficulty doing this using the VM3000 PDM MEMS microphone.

Any help would really be appreciated.

Thanks

5 REPLIES 5
Imen.D
ST Employee

Hello @kcire L.​ ,

Which STM32 are using ?

Have a look at these resources, it may helpful for you depending to your needs.

  • UM2372 User manual STM32Cube PDM2PCM software library for the STM32F4/F7/H7 Series.

The performances for PDM2PCM library and the Frequency required depends on the configuration of many factors : sampling Freq, resolution etc.

The UM2372 provides resources requirements for memories and frequency for a PCM sample rate and detailed the parameters for the configuration of the library.

  • AN5027 Application note Interfacing PDM digital microphones using STM32 MCUs and MPUs
  • AN3998 Application note PDM audio software decoding on STM32 microcontrollers

Hope this helps you 😊!

Imen

When your question is answered, please close this topic by clicking "Accept as Solution".
Thanks
Imen
kcire L.
Associate III

Hi Yes, I have seen those resources you posted. I am using the NUCLEO-F401RE.

Any ideas on how to convert a single sample for each PDM_Filter() call?

Thanks

I am checking if there is a PDM2PCM example

I will try to contact expert internally for helping and I will come back to you with details.

Imen

When your question is answered, please close this topic by clicking "Accept as Solution".
Thanks
Imen
kcire L.
Associate III

Thanks very much! I look forward to hearing back from you.

Hi @kcire L.​ ,

Sorry for my late reply, but I've found it difficult to come back to you as the expert was on leave.

and I just received a response from him that unfortunately there is no such example available.

Imen

When your question is answered, please close this topic by clicking "Accept as Solution".
Thanks
Imen