emUSB-Device Audio

emUSB-Device Audio allows easy transmission of digital audio data via the standardized USB interface by means of plug-and-play on any operating system, without any drivers needed.

Downloads

Documentation

Overview

Using emUSB-Device Audio, an embedded device can be transformed into an audio recorder or an audio speaker. An audio jack and dedicated audio hardware is not necessarily available on every design. emUSB-Device Audio allows the device to handle audio data irrespective of the available hardware, for example audio data played from a PC (Linux/Windows/Mac) can be saved directly onto an SD card.

Key features

Compatible to USB Audio version 1 and version 2 device class
Record audio from the host
Send audio to the host
Arbitrary number of input and output audio streams
Arbitrary number of channels for each audio stream
Sample resolution from 8- to 32-bit
Arbitrary number of audio control units
Synchronous, asynchronous, adaptive and implicit synchronization for each audio stream
Audio interrupt messages
Multi-platform, no drivers needed on Linux, macOS or Windows
High performance
Small footprint

Technical details

SEGGER’s implementation of the Audio class is designed with minimal resource usage in mind, especially targeted to embedded devices. The implementation supports the usage of one or more audio input streams (e.g. to implement a speaker), and one or more audio output streams (e.g. to implement a microphone). All audio streams can be used independently of each other; all may be enabled at the same time allowing audio transfer in either direction.

The Audio class supports all synchronization methods, including methods using feedback endpoints. Audio controls like feature units (volume, mute, etc.), mixer units, and selector units can be configured. emUSB-Device Audio does not provide drivers/codecs for any audio peripherals. Writing a driver to interface with the audio hardware is the customer's responsibility.

Detailed information on resource usage

Example project

Download the emUSB-Device Audio demo for the emPower board:

Program the emPower with the default application using Embedded Studio
Connect the HS USB connector to your PC
Select the emUSB-Device Audio demo as your default sound output and sound input device
Play audio which will be saved onto the SD card
Loopback the emUSB-Device Audio microphone to your speakers to listen to the audio demo

Download emUSB-Device Audio demo for emPower board

SEGGER emPack - emPower 500 — emPower board

Use cases

The audio class is the foundation for any embedded device handling audio data. Whether it has a microphone or speaker, or whether it simply functions as an audio editor.

Typical applications range from speaker phones, conferencing systems, or headsets, to music instruments, voice recorders, music players, or sports wearables.