Regarding imp34dt05 mems sensor configuration

[AmitUpadhyay]

Sir,

I am working on the imp34dt05 sensor but how could we configure its parameter.Could u guide us for that.

What should be sampling frequency and what is the range of the frequency that it can capture and what should be sampling frequency of pcm and what should be size of pcm output and what should be size of buffer and data size of pdm output captured by the stm32f4 controller?

[Matthew_ · Accepted solution]

Hi, can you let us know what peripheral you are using as well as your stm32f4 model? First of all, you should check out AN5027, UM2372, STM32 microphone audio acquisition 8 part YouTube series, your mcu's datasheet, reference manual and check this sample code too -> Link

I hope my answer has helped you. When your question is answered, please select this topic as the solution that answered you, as it will help others find that answer faster.

Thanks for your contribution

[AmitUpadhyay]

Sir,

I am currently working with the STM32L0 series microcontroller, which features an I2S peripheral. My application involves interfacing with a PDM digital MEMS microphone (e.g., IMP34DT05), and I intend to convert the incoming PDM data into PCM format using the PDM2PCM software library.

However, I have observed that STM32CubeIDE does not offer the PDM2PCM middleware component for the STM32L0 series. I have verified that the necessary STM32Cube firmware packages are installed and up to date. Despite this, the middleware option remains unavailable for my target device.

I would like to request guidance on the following:

Whether the PDM2PCM middleware is officially supported for the STM32L0 series.

If not, what is the recommended method for manually integrating the PDM2PCM library into a CubeIDE project for STM32L0?

Are there any performance or compatibility considerations when running the library on a Cortex-M0+ core, especially in real-time audio processing?

If possible, could you provide an example project or reference implementation for STM32L0 using the PDM2PCM library with the I2S interface? Any assistance or documentation you could provide regarding this matter would be greatly appreciated.

[Matthew_]

Hi, I don't exactly know your model, but if your MCU has CRC peripheral, I think you can check this thread. In the official documentation, there is no mention of support for L0 series -> documentation. 

[AmitUpadhyay]

Sir,

We are using STM32L053R8T6 Controller. And this microcontroller has CRC and I2S2 Peripherals but in the document it is not mentioned anywhere.How to use it?

[Chris21]

General use of peripherals including CRC and I2S is described in the reference manual:  https://www.st.com/resource/en/reference_manual/rm0367-ultralowpower-stm32l0x3-advanced-armbased-32bit-mcus-stmicroelectronics.pdf

Likely there are firmware examples available also. 

I don't know about PDM2PC...

[Matthew_]

Hi, you need to first enable CRC to use PDM2PCM libraries. I don't know much about CRC but PDM2PCM library needs it, you can test that in STM32CubeIDE by choosing other supported MCUs. My recommendation is - enable CRC -> then find a way to manually install PDM2PCM library (I think i found some examples in this community, you will need to dig around) and test it. As a last resort, upgrading your MCU to a supported version could be a solution. 

[AmitUpadhyay]

Sir,
I am using the NUCLEO-STM32F401RE board along with the X-NUCLEO-CCA02M2 audio expansion board, which has two MP34DT06 digital PDM microphones.

I want to capture stereo audio and convert it to PCM using the I2S2 peripheral and PDM2PCM middleware in STM32CubeIDE. I’ve seen some examples using timers with PDM microphones, and I’m confused.

Since I2S2 can generate the clock and receive data, do I still need to use a timer in this setup to read stereo PDM data?

I am new to this domain, so any guidance would be helpful.
Thanks.

[Matthew_]

Hello, based on AN5027, you will need external timer to provide pdm clock frequencies for both mics. Please note that the incoming streams will be bit-interleaved, like each bit of pdm stream will alternate between 2 mics [Mic1 Bit, Mic2 Bit, Mic1 Bit, etc.].  For your mcu and expansion board, i think you can also use X-CUBE MEMS1 library (link).

[AmitUpadhyay]

Sir,

It will be easier for us if we use only i2s peripherals along.Could you verify it please if possible.