Five differences to consider when implementing SuperSpeed USB 3.0

August 21, 2014 OpenSystems Media

Universal Serial Buses (USBs) have undergone many technological upgrades and enhancements since their standardization in 1994. As a familiar component to anyone who owns a device with connective capabilities, USBs dominate PC, consumer electronics, and mobile interfaces. Because of their universal functionality, USBs must be able to adapt and change in the same direction with the industry as a whole.

The Internet of Things (IoT) and general tech advancements have created a space for an advanced USB model to fill. The answer is SuperSpeed USB 3.0 and it provides the bandwidth and power capacity needed to take the digital revolution to the next stage.

USB cables have established a reputation as being a quick, inexpensive, and bidirectional solution to connect otherwise independent devices. USB 3.0 comes packed with a series of upgrades that suit it for future devices.

There are five main differences between USB 2.0 and SuperSpeed 3.0, all covered here.

Speed
Needless to say, SuperSpeed 3.0 has increased speed compared to the 2.0 model, more than 10X the capacity. Information transfer rates have gone from 480 Mbps to 5 Gbps, granting faster device updates and removing time constraints.

Physical layering
With the new layering updates, made possible by a dual-simplex data path, packets arrive and leave at the same time. By allowing the two actions to occur simultaneously, users enjoy greater speed and convenience. The information transfers via the new set of connections that are layered over the existing USB 2.0 two-wire interface.

Polling
Polling is a draining task that involves checking the status of different devices throughout a repeated cycle. With USB 3.0, polling is eliminated in favor of asynchronous notification, meaning that a device will only be monitored and begin a new data transfer task once it receives indication that the prior step in a cycle is complete. Polling in 2.0 required all devices to be on at all times for constant monitoring. USB 3.0 lets the host contact specific peripheral devices to communicate when data is ready to transfer on both ends.

Broadcast
SuperSpeed USB 3.0 has also eliminated the need for broadcast between the host and transceivers for required devices. This, like the removal of polling, is a huge power-saving addition. It means that the only devices turned on and using power are the ones that have been notified to do so.

Power
USB 3.0 comes with a trifecta of advancements in available power, unconfigured current limit, and battery capabilities. The overall power from 2.0 to 3.0 has been enhanced from 5 V at 500 mA to 5 V at 900 mA. The unconfigured current has been raised from 100 to 150 mA, and the new battery charging function increases power capability to 5 V at 1,500 mA with compatible hardware. These new power features allow USB 3.0 to foster larger and more technologically intensive projects.

SuperSpeed USB 3.0 is compatible with old devices, while also providing room for growth with newer, more advanced technologies. It offers the same reliable functionalities as the 2.0 model, with these enhancements. USB needs to keep up with the times, because it’s a crucial part of the data-transfer process.

Ankur Tomar is a Technical Marketing Manager for Newark element14, a global electronics distributor and online community of more than 250,000 design engineers and tech enthusiasts. To learn more, visit element14.com.

Ankur Tomar, Newark element14
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