MEMS audio sensor MP23DB01HP Values/Units

[FilipeLourenço]

I have a question about the MEMS audio sensor MP23DB01HP.

I think i already undertood that the output is a PDM, but my question is, how can I convert that to obtain a corresponding value in dB? Or some used unit?

I have done the acquisitons, but know i don't know what to do with that values...

Thank you in advance for your replies

[Andrea VITALI]

What have you acquired? not clear - if you have the PCM (pulse code modulated) stream then you already have everything. If you do not know how to convert from PDM to PCM, then PCM was not saved, did you save the PDM bitstream?

The PDM to PCM conversion can be done by the firmware, check for example AN3998 and UM2372 that describe the API of the library in STM32Cube software packages: 

• AN3998 "PDM audio software decoding on STM32 microcontrollers" AN3998.book 
• UM2372 "STM32Cube PDM2PCM software library for the STM32F4/F7/H7 Series" STM32Cube PDM2PCM software library for the STM32F4/F7/H7 Series - User manual

The PDM to PCM conversion can also be done by a dedicated hardware peripheral on STM32 models equipped with that peripheral, check AN5027 for more information

• AN5027 "Interfacing PDM digital microphones using STM32 MCUs and MPUs" Interfacing PDM digital microphones using STM32 MCUs and MPUs - Application note

Finally, audio processing and fusion such as BeamForming (BF), Sound Source Localization (SL), FFT analysis, and of course PDM to PCM conversion is in X-Cube-MEMSMIC1 software package!

• X-Cube-MEMSMIC1 "Analog and digital MEMS microphone acquisition and processing software expansion for STM32Cube" X-CUBE-MEMSMIC1 - Analog and digital MEMS microphone acquisition and processing software expansion for STM32Cube - STMicroelectronics

 

[FilipeLourenço]

Thanks @Andrea VITALI 

I am using steval mkboxpro with FP-SNS-DATALOG2, and after acquisition i obtained a .dat file, then i used the program that came in  FP-SNS-DATALOG2 to convert .dat to .csv, after opening the .csv i have the timestamps and waveform. Like this:

From what i understand by reading the files and your explanation, the output is a PDM, a stream os 0s and 1s, but i don't have that output. My problem is that i need to have this in db or dbSPL.

[FilipeLourenço]

Any of the solution that you suggested is compatible with using FP-SNS-DATALOG2?