Features

• Complete firmware to implement full-duplex speech communication over

Bluetooth low energy (BLE) using Opus compression

• 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 v1.2.1 (downloadable from http://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 or jack connector

• Sample implementation available for X-NUCLEO-IDB05A1 plus X-NUCLEO-

CCA02M1 connected to a NUCLEO-F446RE or NUCLEO-L476RG, for

SensorTile (STEVAL-STLKT01V1) and BlueCoin (STEVAL-BCNKT01V1)

• Easy portability across different MCU families thanks to STM32Cube

• Free, user-friendly license terms

Description

FP-AUD-BVLINK2 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 the STM32 Nucleo and includes drivers and

middleware for BLE (BlueNRG-MS) and digital MEMS microphones.

The software with the suggested combination of STM32 and ST devices can be

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

or wearable applications.

Thanks to the low bitrates you can achieve while maintaining high voice quality with

Opus, combined with the low power features of BlueNRG, you can develop

applications featuring very low consumption.

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

streaming.

The software runs on the STM32 microcontroller and includes all the necessary

drivers to use the devices on the STM32 Nucleo development board and expansion

boards, as well as on the STEV

AL-BCNKT01V1 and STEVAL-STLKT01V1 evaluation

boards.

It also includes the Opus audio codec as the STM32Cube middleware.

Product summary

STM32Cube

function pack for

full-duplex voice

streaming over

Bluetooth Low

Energy via Opus

compression

FP-AUD-BVLINK2

Bluetooth low

energy expansion

board based on

SPBTLE-RF

module for STM32

Nucleo

X-NUCLEO-

IDB05A1

Digital MEMS

microphone

expansion board

based on

MP34DT01-M for

STM32 Nucleo

X-NUCLEO-

CCA02M1

SensorTile

development kit

STEVAL-

STLKT01V1

BlueCoin starter kit

STEVAL-

BCNKT01V1

STM32Cube function pack for full-duplex voice streaming over Bluetooth low

energy using Opus compression

FP-AUD-BVLINK2

Data brief

DB3552 - Rev 1 - March 2018

For further information contact your local STMicroelectronics sales office.

www.st.com

1 Detailed description

■

What can you do with STM32Cube function packs?

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

boards, and STM32Cube and X-CUBE software, to create function examples, embodying some of the most

common use cases, for each application area.

These software function packs are designed to exploit as much as possible the underlying STM32 ODE hardware

and software components to best fit the requirements of final users’ applications.

Moreover, function packs may include additional libraries and frameworks which do not present the original

X-CUBE packages, thus enabling new functionalities and creating a real and usable system for developers.

What is STM32Cube?

STMCube™ is designed by STMicroelectronics to reduce development effort, time and cost across the entire

STM32 portfolio.

STM32Cube version 1.x includes:

• STM32CubeMX, a graphical software configuration tool that allows the generation of C initialization code

using graphical wizards.

• A comprehensive embedded software platform specific to each series (such as the STM32CubeF4 for the

STM32F4 series), which includes:

– the STM32Cube HAL embedded abstraction-layer software, ensuring maximized portability across the

STM32 portfolio

– a consistent set of middleware components such as RTOS, USB, TCP/IP and graphics

– all embedded software utilities with a full set of examples

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 BlueNRG-MS, MEMS microphone

expansion boards, SensorTile and BlueCoin; 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 (BlueVoiceOPUS).

The third party Opus (v1.2.1) 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 message. 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 middleware is responsible for audio encoding and periodic data transmission on the server

side and for decoding of received data 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. The receiver 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. Depending on the hardware used, the audio can be

played through a jack connector. Both the central and the peripheral modules can act as a transmitter and a

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

FP-AUD-BVLINK2

Detailed description

DB3552 - Rev 1

page 2/4