STM32 USB Microphone

Description

The STM32 USB Microphone, or STM32MIC for short, is a self-contained, USB-bus powered unit with an embedded micro controller that implements a crystal-less stereo USB microphone interface. The board demonstrates how PDM microphone data is preprocessed by a DSP and then converted into I2S-format which is streamed over USB to a host computer.

The STM32MIC package includes the full micro controller software source code (in C-source code for MDK ARM, free version) that implements I2S to USB streaming audio, sample rate control, I2C interface to control the microphone processing in the DSP. With this variant you will get a fly start for a STM32 USB Microphone design-in regarding both hardware and the software.

If you are interested in the hardware only, we recommend the BR262HM1.1 which is hardware identical, but does not include the micro controller source code.

Key Features

The STM32MIC has the following key features:

• Compact form factor of only 50 mm x 25 mm
• ST Microelectronics STM32L052R8H6 micro controller
• Two MEMS microphones spaced 10 mm apart (Knowles part number SPU0410HR5H-PB)
• The DSP BelaSigna R262 (BR262W26A103E1G) from ON Semiconductor is processing the microphone signals to yield enhanced output signals in PDM format
• The ADAU7002ACBZ converts the enhanced PDM signals from the DSP into a stereo I2S signal
• The stereo I2S signal is streamed as a stereo 32 kHz, 16 bit USB microphone interface to the host computer

After purchase, you will receive a link to the source code. This is available for download within 30 days.

Documentation

• Product brief (PDF)
• Schematic (PDF)
• Assembly Information (PDF)