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June 2014

DocID026565 Rev 1

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STEVAL-MKI138V3

STAudioHub USB interface board based on MP45DT02 and STM32

Data brief

Features

• Sound card automatically recognized by a PC

as an audio device.

• MEMS microphones provide a high frequency

data stream (1 to 3.25 MHz) of 1-bit digital

samples (PDM technique)

• Audio signals collected from the microphones

are sent to the PC by USB (powered and

connected to PC through USB)

• LED status indicator

• RoHS compliant

Description

The purpose of the STEVAL-MKI138V3

STAudioHub evaluation board is to demonstrate

the decoding and streaming performance of

digital MEMS microphone outputs.

The STEVAL-MKI138V3 hosts the MP45DT02

top-port digital microphone, which works as a

sensor, and the STM32F107RC microcontroller,

working as an audio decoder.

These microphones are analog-to-digital

transducers. They are able to sense sound

pressure and convert this signal into a digital

signal using the PDM technique.

The STM32 microcontroller decodes the PDM

signal coming from the microphones and streams

the audio via the USB.

The STEVAL-MKI138V3 evaluation board is a

sound card which is automatically recognized by

a PC as an audio device. Connection is made

through a USB cable, which also supplies the

board, and then streams the audio collected from

the microphones to the PC.

It is also possible to use the board as an interface

for other microphone PCBs (STEVAL-MKI126Vx).

In this case is recommended the use of the

APWorkbench software tool.

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