FP-AUD-BVLINKWB1

Application

STM32 WPAN USB Device PDM Lib

OPUS

Middleware

STM32Cube Hardware Abstraction Layer (HAL)

Hardware

Abstraction

Hardware

STM32 Nucleo development board

Discovery board

STM32 Nucleo expansion boards

X-NUCLEO-CCA02M1 (Sense)

Features

• Complete firmware to implement full-duplex audio streaming over Bluetooth 5.0

using Opus codec for both encoding and decoding

• A BlueVoiceOPUS customized profile for audio over BLE, including an easy-to-

use set of APIs to exploit advanced Opus functionality (source code available)

• Third-party Opus v1.3 (downloadable from https://www.opus-codec.org)

middleware: an open, royalty-free and highly versatile audio codec that is

standardized by the Internet Engineering Task Force (IETF) as RFC 6716

• Digital audio signal acquisition and processing

• Audio out playback through USB

• Sample implementation available for X-NUCLEO-CCA02M1 connected to a P-

NUCLEO-WB55

• Compatibility with STBLESensor app (v 4.2.0 or higher) for Android, to perform

audio streaming at 16 kHz and speech-to-text

• Free, user-friendly license terms

Description

FP-AUD-BVLINKWB1 is an STM32Cube function pack that performs voice streaming

over BLE in a full-duplex configuration using the advanced Opus compression

algorithm.

The application runs on P-NUCLEO-WB55 and includes drivers and middleware for

BLE and digital MEMS microphones. It also includes the complete Opus audio codec

(v 1.3) as third-party middleware.

The peripheral module can also stream audio to an Android device running the

STBLESensor app v 4.2.0 or higher.

The software with the suggested combination of STM32WB and ST devices can be

used, for example, to develop wireless audio communication systems for smart home

or wearable applications.

The Opus algorithm provides the flexibility to achieve high voice quality even at low

bitrates, and the STM32WB has the low power capabilities to allow the development

of applications featuring very low consumption.

The same audio codec can be used to implement high quality stereo music

streaming, depending on the available resources.

Product summary

STM32Cube function

pack for STM32WB

MCU featuring full-

duplex audio streaming

over Bluetooth 5.0

using Opus codec

FP-AUD-

BVLINKWB1

Digital MEMS

microphone expansion

board based on

MP34DT01-M for

STM32 Nucleo

X-NUCLEO-

CCA02M1

Bluetooth 5 and

802.15.4 Nucleo pack

including USB dongle

and Nucleo-68 with

STM32WB55 MCUs

P-NUCLEO-

WB55

BLE sensor application

for Android and iOS

STBLESensor

STM32Cube function pack for STM32WB MCU featuring full-duplex audio

streaming over Bluetooth 5.0 using Opus codec

FP-AUD-BVLINKWB1

Data brief

DB3973 - Rev 1 - July 2019

For further information contact your local STMicroelectronics sales office.

www.st.com

1 Detailed description

1.1 What can you do with STM32Cube function packs?

STM32Cube function packs leverage the modularity and interoperability of STM32 Nucleo and X-NUCLEO

boards together with STM32Cube and X-CUBE software to create function examples for some of the most

common use cases of different application technologies.

These software function packs are designed to exploit the underlying STM32 ODE hardware and software

components as much as possible to best satisfy the requirements of final user applications.

Moreover, function packs may include additional libraries and frameworks that are not present in the original X-

CUBE packages, thus enabling new functionalities allowing real and usable system for developers.

1.2 What is STM32Cube?

STM32Cube is a combination of a full set of PC software tools and embedded software blocks running on STM32

microcontrollers and microprocessors:

• STM32CubeMX configuration tool for any STM32 device; it generates initialization C code for Cortex-M

cores and the Linux device tree source for Cortex-A cores

• STM32CubeIDE integrated development environment based on open-source solutions like Eclipse or the

GNU C/C++ toolchain, including compilation reporting features and advanced debug features

• STM32CubeProgrammer programming tool that provides an easy-to-use and efficient environment for

reading, writing and verifying devices and external memories via a wide variety of available communication

media (JTAG, SWD, UART, USB DFU, I2C, SPI, CAN, etc.)

• STM32CubeMonitor family of tools (STM32CubeMonRF, STM32CubeMonUCPD, STM32CubeMonPwr) to

help developers customize their applications in real-time

• STM32Cube MCU and MPU packages specific to each STM32 series with drivers (HAL, low-layer, etc.),

middleware, and lots of example code used in a wide variety of real-world use cases

• STM32Cube expansion packages for application-oriented solutions

1.2.1 How does this STM32Cube function pack complement STM32Cube?

This software is based on the STM32CubeHAL hardware abstraction layer for the STM32 microcontroller. The

package extends STM32Cube by providing a board support package (BSP) for the MEMS microphone expansion

board and STM32WB Nucleo board, as well as middleware components for audio acquisition, communication

with other BLE devices, USB streaming of recorded signals and a dedicated profile for full-duplex speech

transmission over BLE (bvopus_service_stm).

The third party Opus (v1.3) middleware is included in the function pack.

The BlueVoiceOPUS profile defines a BLE service which includes one characteristic for audio transmission and

one for optional control messages. In a full-duplex system, both sides of the communication (central and

peripheral) can act as a server of information. Periodic notifications containing compressed audio data are sent

from the central node acting as a server to the peripheral node acting as a client, and vice versa.

The BlueVoiceOPUS service is responsible for audio encoding and periodic data transmission on the server side

and for received data decoding on the client side.

The drivers abstract low-level hardware details and allow the middleware components and applications to access

the devices in a hardware-independent fashion.

The package includes a sample application that developers can use to start experimenting with the code. It

enables audio acquisition, compression and transmission over BLE from the module acting as a transmitter to the

module acting as a receiver, which is responsible for audio decompression and USB streaming of audio data to a

PC.

The system is recognized by the PC as a standard microphone, and any freeware or commercial audio recording

software can be used to interface with it. Both the central and the peripheral modules can act as a transmitter and

a receiver at the same time, enabling full-duplex voice streaming.

The peripheral module can also stream audio at 16kHz to an Android device running the STBLESensor app (v

4.2.0 or higher).

FP-AUD-BVLINKWB1

Detailed description

DB3973 - Rev 1

page 2/4