Gather sound with Sony Spresense and digital microphone

Sketch Example for Spresense, if developed in Arduino Audio/application/recorder Sample Sketch

theAudio->setRecorderMode(AS_SETRECDR_STS_INPUTDEVICE_MIC);

can be digitized by changing the .

err_t setRecorderMode(
      uint8_t input_device,
      int32_t input_gain,
      bool is_digital
  );

So,

theAudio->setRecorderMode(AS_SETRECDR_STS_INPUTDEVICE_MIC, 0,0x4000,true);

You can record with a digital microphone by changing to the .

However, if Gain is digital, it cannot be set to 0 or higher, so the sound is quite low and you may need to do Gain Up in software.

The following pages were helpful.

Record in MP3 format|Spresense Arduino Sample & Tutorial

IM69D130 is a Pulse Density Modulation (PDM) output, so you can get the data by sending a clock from the Presense side and reading the data accordingly.Since it is a PDM, the data that appears can be either 0 or 1.

The PDM data must be digitally signal-processed and converted to digital audio signals, or output as is and converted to analog audio signals through a low-pass filter.

In the Arduino library list, click
"Adafruit Zero PDM Library
PDM Microphone Input Library for Arduino Zero/Adafruit Feather M0 (SAMD21 processor).

You may be able to use it, so why don't you check it out?