What is SoundWire interface | Advantages of SoundWire protocol

This page covers SoundWire interface protocol basics. It mentions benefits or advantages of SoundWire interface.

Introduction : The initial version of SoundWire is published in 2014 by MIPI Alliance group of companies. Latest version is SoundWire V1.2.1 published in June 2022.

What is SoundWire protocol ?

This is audio interface used in mobile phones, PCs, tablets, wearables and other devices. SoundWire is used as command/control protocol. It utilizes 2 pin and offers multi-drop interface using DATA and CLOCK lines. Each frame of SoundWire protocol can transmit read or write command. It does not require control interfaces as used in I2S/I2C. This audio architecture supports 11 slave devices with each master. The devices can be interfaced in different topologies such as basic system stereo I/O, daisy chain, star, Multi-lane, bridge, multiple masters with function split/ alternate partitioning etc.

Following are the features of SoundWire Interface developed by MIPI Alliance.
• 2 pin Data and Clock, 1.2V or 1.8V
• Dual data rate : Sampled on each edge, NRZI encoding
• Clocking up to 12.288 MHz, Clock stop
• Frame length (adjustable)
• Transports frames with PCM (Pulse Code Modulation) and PDM (Pulse Density Modulation) formats
• Isochronous and asynchronous mode
• Bulk transfer capability
• Event Signalling
• Enumerable bus (Software handles enumeration)
• Device types supported (Master, Slave, Monitor equipments) and supports 48 bit device ID

The functionalities and roles of SoundWire devices are as follows.
➨Master : It offers clock and synchronization between devices and master. It offers bus management.
➨Slaves : It is available in the form of audio components which support wake-up capabilities and utilizes in-band interrupts. Audio peripherals can be audio codec, microphone, speaker, amplifier, bluetooth, FM radio etc.
➨Monitoring equipments : Equipments can monitor, debug and test data over the bus.

Soundwire interface can be used to connect application processor with multiple digital microphones and speakers. The first ware of 5G smartphones will be equipped with Soundwire and its complement interface known as SLIMbus.

Benefits or advantages of SoundWire

Following are the benefits or advantages of SoundWire:
➨This interface simplify integration of multiple audio components across wide range of platforms and devices.
➨It supports low gate count hardware designs which minimizes cost.
➨It uses configurable frame sizes which reduces transport overhead.
➨Number of data channels and number of data ports are configurable based on bandwidth requirements of a peripheral. A data port supports 1 to 8 channels and a slave supports up to 14 data ports.
➨It offers superior power and performance compare to other audio connectivity standards.

➨Also refer advantages or benefits of SLIMbus interface protocol, Unipro interface protocol >> and M-PHY Physical layer >>.

Refer advantages and disadvantages of following interface protocols.
UART,   SPI,   I2C,   I2S,   Serial interface,   Parallel interface

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