Lattice Blog


Alternate Avenues – Using USB Type-C Alt Mode

USB Type-C Alt Mode
Posted 03/15/2016 by Abdullah Raouf

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Apple made it the only connector on the new MacBook. LG put it on the G5, their flagship phone. USB Type‑C™ looks to be game-changer, with multiple optional features, such as the ability to support up to 10 Gbps of data, 100W of power, and UHD video in a small reversible connector the size of microUSB.

Realizing the vision of a single universal connector that combines data, video and power has been tried before, but previous attempts always had challenges. USB Type-C promises to be different, with a couple of key advantages that position it for success.

The biggest advantage is who’s backing it. This connector comes from the USB IF Forum, the organizing body that manages USB, one of the most popular peripheral standards in the world. The ubiquity of USB means that USB Type-C comes to market with a broader built-in base of support than even the largest of companies could build.

Another advantage is the introduction of USB Type-C Alt Mode. Many previous attempts to create a universal connector mandated exactly how power, data and video could be sent. USB Type-C is trying something different. Data and power are still mandated, however with video, the Type-C designers have taken a more agnostic approach.

This is a smart move because the video I/O space doesn’t have any one standard with the ubiquity of USB. Rather, several video standards each have global adoption in different applications. In the computing space, DisplayPort is popular due to its broad monitor support and workspace-friendly features such as the ability to daisy-chain monitors. In the home theater market, HDMI® has long held reign with billions of products on the market, while more recently, MHL® has gained traction as a mobile video technology that is compatible to HDMI.

In order to support the various video standards, the USB IF has designated pins for generic video use. Initial handshaking and configuration is done through VDMs pins, and the different video standards each define how the reserved pins are used to support their standard. These are called USB Type-C Alt Modes.

Lattice already offers a portfolio of USB Type-C FPGA and ASSP solutions to suit a variety of market needs. Recently we partnered with MediaTek to introduce a reference platform that supports 4K video over a USB Type-C connector using the MHL protocol. Using this platform you can connect mobile devices to a 4K monitor, with simultaneous support for USB 3.1 data, to create a truly seamless experience. For more details check out our press release here.

The backing of USB and the flexibility of these Alt Modes in a reversible connector (solving the main complaint around USB for most consumers) position USB Type-C for success. This is good news for the consumer electronics industry. Once you have a single connector that is broadly adopted and that can support video, data, and power simultaneously, a whole new world of peripherals open up. Displays can charge your laptop when you plug into them. Smartphones can plug into a monitor and become computers. The rat’s nest of cables behind your desk can be eliminated, and replaced with a single chain of cables that supply all the power, data and video to each device. All of which points to big things ahead for this tiny connector.