Microphone Class Reference

A class to control MEMS microphone. More...

#include <Microphone.h>

Public Member Functions
int	begin ()
	Initialize the PDM MEMS microphone.
int	getSamples (int16_t *buffer, size_t samples)
	Read PCM samples from the microphone buffer.
	Microphone (uint8_t dataPin, uint8_t clkPin)
	Construct a new Microphone object.
void	setCallback (pdm_samples_ready_handler_t handler)
	Set a callback function to be called when new samples are ready.
int	start ()
	Start capturing audio samples.
void	stop ()
	Stop capturing audio samples.

Detailed Description

A class to control MEMS microphone.

This class provides control for the PDM MEMS microphone connected via PIO.

**Microphone (PDM_CLK — GPIO 15, PDM_DATA — GPIO 16)**

• Based on the [Arm Developer Ecosystem Microphone Library for Pico] (https://github.com/ArmDeveloperEcosystem/microphone-library-for-pico/tree/main)
• Uses PIO for PDM capture and OpenPDM2PCM for conversion to PCM.

Default microphone parameters:

Setting	Value
Data pin	PDM_DATA (GPIO 16)
Clock pin	PDM_CLK (GPIO 15)
Sample rate	16 kHz
Buffer size	256 samples

Constructor & Destructor Documentation

Microphone()

Microphone::Microphone	(	uint8_t	dataPin,
		uint8_t	clkPin )

Construct a new Microphone object.

Parameters

dataPin	GPIO pin connected to the PDM data signal (default: GPIO 16)
clkPin	GPIO pin connected to the PDM clock signal (default: GPIO 15)

Member Function Documentation

begin()

int Microphone::begin

(

)

Initialize the PDM MEMS microphone.

Configures the microphone using PIO to capture PDM data and the OpenPDM2PCM library to transform it into PCM samples.

Implementation is based on the official [Arm Developer Ecosystem microphone library for Pico] (https://github.com/ArmDeveloperEcosystem/microphone-library-for-pico/tree/main).

Default parameters:

• Data pin: GPIO 16
• Clock pin: GPIO 15
• Sample rate: 16 kHz
• Buffer size: 256 samples

Returns

0 on success, negative value on error.

getSamples()

int Microphone::getSamples	(	int16_t *	buffer,
		size_t	samples )

Read PCM samples from the microphone buffer.

Parameters

buffer	Pointer to an array where the samples will be stored.
samples	Number of samples to read.

Returns

The number of samples actually read, or negative on error.

setCallback()

void Microphone::setCallback

(

pdm_samples_ready_handler_t

handler

)

Set a callback function to be called when new samples are ready.

Parameters

handler

Callback function of type ::pdm_samples_ready_handler_t.

start()

int Microphone::start

(

)

Start capturing audio samples.

Returns

0 on success, negative value on error.

stop()

void Microphone::stop

(

)

Stop capturing audio samples.

Returns

0 on success, negative value on error.

---

The documentation for this class was generated from the following file:

• src/Microphone.h