Skip to content | Skip to navigation
Im Auftrag von RSIm Auftrag von RSIm Auftrag von RS

What's the most important test equipment and design considerations when developing around USB3?

3 Feb 2012

BbiteTom

United Kingdom

What's the most important test equipment and design considerations when developing around USB3? Courtesy of Wikipedia USB 3.0 is the second major revision of the Universal Serial Bus (USB) standard for computer connectivity. In late 1990’s, the first major revision was made to the USB1.1 specification. It was done by adding a new transfer speed called High Speed (HS =- 480Mbps) to the earlier Speeds (Low Speed/LS- 1.5 Mbps and Full Speed/FS - 12Mbps). This revision was called USB2.0. USB3.0 specification uses the same concepts of USB2.0 but with lots of improvements and totally different implementation. Earlier USB concepts like Endpoints and four transfer types (Bulk, Control, Isochronous and interrupt ) are preserved but the protocol and electrical interface is significantly different. It is so different that the specification defines physically separate channel to carry USB3 traffic. The changes in this specification makes improvements in the following area: transfer speed – added a new transfer type call Super Speed or SS – 5Gbps (electrically it is more similar to PCIe Gen2 than USB2) more bandwidth – instead of one-way communication USB3 uses two unidirectional data paths: one to receive data and the other is to transmit power management – U0 through U3 link power management states are defined. improved bus utilization – a new features is added (using packets NRDY and ERDY) to let device asynchronously notify the host its readiness (no need of polling) support to rotating media – Bulk protocol is updated with a new feature called Stream Protocol that allows a large number of logical streams within an Endpoint. USB 3.0 has transmission speeds of up to 5 Gbit/s, which is 10 times faster than USB 2.0 (480 Mbit/s). USB 3.0 significantly reduces the time required for data transmission, reduces power consumption, and is backwards compatible with USB 2.0. The USB 3.0 Promoter Group announced on 17 November 2008 that the specification of version 3.0 had been completed and had made the transition to the USB Implementers Forum (USB-IF), the managing body of USB specifications.[1] This move effectively opened the specification to hardware developers for implementation in future products.