MIPI Introduces SoundWire Audio Interface for Mobile Devices
MIPI (Mobile Industry Processor Interface) Alliance is a non-profit corporation that establishes standards for hardware and software interfaces in mobile devices. MIPI is better known for its MIPI DSI (Display Serial Interface) and CSI (Camera Serial Interface), but as you can see from the diagram below, they’ve been busy publishing a lot more interface specifications. The latest being MIPI SoundWire, a new audio interface for amplifiers, microphones and audio codecs used in smartphones, tablets, mobile PCs and other devices.
The consortium only released a “MIPI SoundWire Specification Brief” so there aren’t that many details. SoundWire is not the first audio interface from MIPI, with SLIMbus having been first introduced in 2007, and later updated in 2013 with SLIMBus 1.1. SLIMbus must not have been that widely used, as only Intrinsyc OPEN-Q 8084 Development Kit appears to feature the interface among all the board listed on CNX Software.
Nevertheless SLIMBus and the new SoudnWire share some of the same specifications:
- Two-wire (clock and data), 1.2 or 1.8 V, time-division transport
- Embedded control and data channels to support audio, data and control applications.
- Support for multiple clocks, including natural audio clocks (24.576, 24, 19.2 MHz)
- Isochronous and asynchronous modes
- PCM format
But SoundWire also brings some improvements with support for double data rate, configurable frame size, lower complexity, PDM (Pulse Density Modulation) format, multichannel data, and more…
25 companies have been involved in SoundWire development, products based on MIPI SoundWire are already in development and IP, silicon components and test tools based on the specification are expected to become commercially available also by year-end 2014, or early 2015.