June 2013 DocID024359 Rev 2 1/4
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STEVAL-MKI138V1
STAudioHub USB interface board
based on MP34DT01 and STM32
Data brief
Features
• Powered and connected to PC through USB
• Sound card automatically recognized by the
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 collected from the microphones is sent to
the PC through USB
• LED status indicator
• RoHS compliant
Description
The purpose of STEVAL-MKI138V1 is to provide
a demonstration of decoding and streaming of
digital MEMS microphone outputs.
The STEVAL-MKI138V1 demonstration board
hosts the MP34DT01 (top-port digital
microphone), working as a sensor and the
STM32F107RC microcontroller, which functions
as an audio decoder.
These microphones are analog-to-digital
transducers. They are capable of sensing sound
pressure and converting it to a digital signal using
the PDM technique.
The STM32 microcontroller decodes the PDM
signals from the microphones and streams the
audio via USB.
The STEVAL-MKI138V1 is a sound card
automatically recognized by the PC as an audio
device. Connection is made through a USB cable,
which both powers the board and streams the
audio collected from the microphones to the PC.
It is also possible to use the STEVAL-MKI138V1
as an interface board for other microphone
boards (STEVAL-MKI126Vx), in which case use
of the APWorkbench software tool is
recommended.
www.st.com
