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The MIPI Alliance exists to standardize widely used interfaces in mobile, such as those to cameras, displays, sensors, and more. I think MIPI originally stood for mobile industry processor interface when it was created, but now it says that "MIPI is not an acronym and has no specific meaning." The audio interface is called MIPI SoundWire and is intended to replace older approaches that present limitations to system designers in terms of power, pin-count, ease of integration, or lack of scalability. SoundWire is a digital audio interface specification, originally introduced in 2014, that can replace legacy audio interfaces, reducing the cost of supporting high-
quality audio through reduced pin count, ease of integration, and low gate count. These system design benefits, and scalability of the solution from simple to high-end audio, make the standard attractive to many design applications.
MIPI SoundWire is well suited to a wide range of devices from low-cost, low-bandwidth peripherals to high-performance audio codec devices such as personal computers, high-end smartphones, headphones, and hearing aids, to name a few. It can be optimized for different applications, as small as <10K gates for the slave implementation for cost-sensitive peripheral devices. The latest version of the MIPI SoundWire standard is 1.1.
Cadence recently announced that they have delivered the industry’s first Design and Verification IP for MIPI SoundWire v1.1 and demonstrated interoperability of MIPI SoundWire solutions in collaboration with Realtek. Interoperability was proven between the Cadence IP for MIPI SoundWire Master v1.1 and Realtek’s device with MIPI SoundWire Slave v1.0 interface, demonstrating the high quality of the IP. The complete solution includes master and slave design as well as Verification IP with TripleCheck for compliance testing. The interoperability testing included traffic in both directions. Achieving interoperability took just a few hours. Of course, VIP is used to verify the designs before tapeout, but achieving interoperability between multiple companies is the gold standard for implementation.
Using this IP allows design groups to adopt MIPI SoundWire in consumer products as a way to provide a scalable, low-complexity, low-latency, low-power, 2-pin multi-drop bus implementation that allows multiple audio streams to be transferred, opening up deployment of new advanced amplifiers, microphones, and headphones.
On a related topic, today the standard connector for audio is the 3.5mm jack. Every phone in the world has one. We will have to wait a couple more months to find out whether the rumors are true that Apple is going to remove the 3.5mm connector from the next iPhone and replace it with a single connector, either their proprietary "lightning" connector (the one on current iPhones) or perhaps with USB Type-C, which is the only connector on the current 12" MacBook (if you buy a monitor that provides USB Type-C capability, then that single connector is the power supply connector, the display connector, and the connector for other USB devices, all of which connect through the monitor itself). The consensus of the net seems to be that Apple will continue with their proprietary connector. Of course, this also means that there will need to be adaptors to be used with existing headphones, although I just looked and you can already get Beats headphones with a lightning connector.
Breaking news: There is no 3.5mm jack on the iPhone 7 and 7+. It comes with lightning-based ear-buds, and a lightning to 3.5mm adapter, and supports the new Apple wireless earbuds.
To learn more about Cadence IP solutions for MIPI, please visit: www.cadence.com/go/mipi-soundwire.
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