USB 3.0USB 3.0

Content OverviewContent Overview• Introduction to USB 3.0• History of USB

o Overview

• Time chart• Connectors• Architecture• Dataflow• Packets• Summary

IntroductionIntroduction• Universal Serial Bus (USB) is a standard interface

for connecting peripheral devices to a host computer. The USB system was originally devised by a group of companies including Compaq, Digital Equipment, IBM, Intel, Microsoft, and Northern Telecom to replace the existing mixed connector system with a simpler architecture.

• The USB standard is maintained and enforced by the USB Implementers Forum (USB-IF).

IntroductionIntroductionUSB 3.0 specification include a number of significant changes including:•Higher data transfer rate (up to 5 Gbps)•Increased bus power and current draw•Improved power management•Full duplex data communications•Link Training and Status State Machine (LTSSM)•Interrupt driven, instead of polling•Streaming interface for more efficient data transfers

USB HISTORYUSB HISTORYUSB 1.0 specification introduced in 1994USB 2.0 specification finalized in 2001Became popular due to cost/benefit

advantage Eg. IEEE 1394 – high bandwidth, high cost

Three generations of USB USB 1.0 USB 2.0 USB 3.0 and WUSB

Also referred to as SuperSpeed USB Speeds 10x faster than USB 2.0 (5 Gbps in

controlled test environment) Extensible – Designed to scale > 25Gbps

Optimized power efficiency No device polling (asynchronous notifications) Lower active and idle power requirements

Backward compatible with USB 2.0 USB 2.0 device will work with USB 3.0 host USB 3.0 device will work with USB 2.0 host

USB:TIME CHARTUSB:TIME CHART

USB 3.0 - USB 3.0 - TimelineTimeline

Promoter Group: Hewlett-Packard, Intel, Microsoft, NEC, ST-NXP Wireless and Texas Instrument

Contributors Group contained over 200 companies (Nov 2007)

USB 3.0 Specification became available Nov 2008

USB 3.0 USB 3.0

ConnectorsConnectors

Added pins for SuperSpeed USB signals

Compatibility for USB 2.0 connectors

USB 3.0 Standard B connector (middle) contains power and ground pins for device to supply power

Physical FeaturesPhysical Features

USB 2.0 Male Ports USB 2.0 Port and USB 3.0 Male Port

Current Devices using USB 3.0 Current Devices using USB 3.0

USB 3.0 ARCHITECTURE

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• USB 3.0 is a physical SuperSpeed bus combined in parallel with a physical USB 2.0 bus

USB 2.0 VS USB 3.0 USB 2.0 VS USB 3.0 • Usb 2.0 uses a 3-part transaction(token,

data,handshake)• In USB 3.0, for OUT transactions, the token is

incorporated in the data packet.• For IN transactions the token is replaced by a

handshake.• USB3.0 supports continuous data bursting.

• USB3.0 is a dual-simplex unicast bus so INs and OUTs can occur concurrently.

• USB3.0 uses asynchronous notifications instead of polling.

• USB3.0 supports streaming for bulk endpoints.• USB3.0 allows isochronous devices to

autonomously enter power link states between service intervals.

• USB3.0 Adds a mechanism for devices to send a Bus Interval Adjustment Message.it allows the driver to change the SOF interval to +/- 13.333 microseconds.

• USB3.0 Supports link level power management that may be initiated from either end of the link.

• In USB3.0 the transmitter may send multiple data packets before receiving handshake unlike in USB2.0.

• USB3.0 packets are send over a dedicated path between host and target device unlike USB2.0 which broadcasts.

• Asynchronous notifications replace USB2.0 polling (this allows devices and links to go into power states, it preserves the bandwidth also)

Super speed packetsSuper speed packets• Link Management Packets• -Traverses only the pair of directly connecting

ports• -Used to manage that link• Transaction packet• -Traverse all links in the path directly connecting

the host and a device.• - Use to control the flow of data packets,

configure device and hub.

Data Packet-Traverse all links in the path directly connecting the host and a device- Consist of two parts-Data Packet Header (DPH) Similar to TP-Data Packet Payload (DPP) Data BlockIsochronous Timestamp Packet-Multicast packet sent by host to all active links

ConclusionConclusion• The current total of PCs and peripherals that can be

connected via USB totals over 10 billion, and this number is increasing by three billion each year. A growing proportion of these now use 3.0 technology, as the majority of motherboard, PC and notebook manufacturers have already launched products with a 3.0 port. According to studies, by 2015 the number of devices with USB 3.0 will have surpassed two billion, and the ratio of computers with built-in USB SuperSpeed connections is expected to reach 100%. According to In-Stat surveys, around 70 million USB 3.0 devices were sold in 2011, but by 2014 this number is predicted by the analysts to rise to one billion.