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Test & Measurement on the computer. There was a lot of consideration put into every aspect of typical usage models for mechanical robustness, current sourcing, scalable bandwidth, host or device role swapping, and even supporting other signalling or "alternate mode" as it's referred to in the specification. Figure 3. A USB Type-C connector measures about 8.25 mm side, smaller than a USB 3.0 connector. It's worth discussing alt mode. This is a user definable mode that lets you transmit anything you want over the USB cable. One example is DisplayPort, which has now adopted the Type- Figure 4. A USB Type-C connector adds duplicate power, ground and data connections that can enhance performance. C cable as an option. The Type-C connector's flexibility means the DisplayPort alt mode can also choose to transmit on just one or two of the four available signal lanes, allowing remaining lanes for 10 Gbps USB data. Over time, alt mode will be used for a lot of other video, audio, and power applications. It's a bit ironic that on one hand USB is all about standardisation, but with alt mode, implementers can create plug-and-play devices that only work with their brand of devices. Physically, the Type-C port and connector is most similar to that of the Micro-B USB. Figure 3 compares the USB 3.0 Micro-USB plug to the Type-C plug. A Type-C port measures 8.4 x 2.6 mm, meaning it's small enough for use on even the smallest peripheral devices. Unlike the Micro-B plug, the Type-C plug has a duplicate set of pins that can be used in either direction. The USB 2.0 differential pair and VCONN pins are duplicated on the receptacle side. As you can see in Figure 4, the Type-C connector has more signals such as RX2 and TX2, plus additional ground pins. These new signals, plus the additional power and ground pins, allow for as much as 100W (20V, 5A) and more intelligent bus configuration capabilities. Looking toward the future, it's not hard to imagine that the duplicate set of pins could be put to use to further boost data transfer throughput through lane aggregation. The article goes on to discuss the modified definitions of pass/fail testing that will prevail with the updated standard. Click to download the pdf; for part 1 of this article, click here. Download PDF of Article Find USB 3.1 on EETsearch 22 EDN Europe | MAY 2015 www.edn-europe.com


EDNE MAY 2015
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