USB Universal Serial Bus

USB(Universal Serial

Bus)

G.Krishna Koushik

Birth of USB A group of seven companies began the development of USB in 1994. Compaq,DEC,IBM,Intel,Microsoft,NEC and NortelIt was developed to make easy to connect external devices to PC. Ajay V. Bhatt is an Indo-American computer architect who helped define and develop USB

The goal was to make it fundamentally easier to connect external devices to PCs by replacing the multitude of connectors at the back of PCs.

GOAL

Various

Different Types Of USB Plugs and Jacks

USB System DesignThe design architecture of USB is asymmetrical in its topology, consisting of a host, a multitude of downstream USB ports, and multiple peripheral devices connected in a tiered-star topology.USB device communication is based on pipes ( A pipe is a connection from the host controller to a logical entity, found on a device)

Host ControllerOnly one host in any USB systemTypically implemented in PC chipset (root hub) Host responsibilities • Detect attachments and removals • Manage control and data flow between host and devices • Monitor status and activity • Provide power to attached devices

Four types of Data TransfersControl (all devices must support)Interrupt (keyboards, mice, joysticks)Bulk (printers, scanners, storage devices) Isochronous (web-cams, speakers)

Release Name Release Date Speed

USB 0.8 December 1994

USB 0.9 April 1995USB 0.99 August 1995USB 1.0 January 1996 Low Speed

(1.5 Mbit/s), Full Speed (12 Mbit/s)

USB 1.1 August 1998USB 2.0 April 2000 High

Speed(480 Mbit/s)

USB 3.0 November 2008

SuperSpeed(5 Gbit/s)

USB 3.1 July 2013 SuperSpeed+(10 Gbit/s)

Generations of USB

Generations of USBUSB 1.0 specified data rates of 1.5 Mbit/s (Low Speed) and 12 Mbit/s (Full Speed).

It did not allow for extension cables or pass-through monitors, due to timing and power limitations.

USB 1.1 was the earliest revision that was widely adopted and led to Legacy-free PCS

USB 1.0

USB 2.0

A big step in USB’s evolution was version 2.0

Support for much faster transfers.

A 40-times increase was found to be feasible, for a bus speed of 480

Megabits per second.

USB 3.0

 Communication is full-duplex in Super Speed transfer mode

Extensible – Designed to scale > 25GbpsSpeeds 10x faster than 2.0 (5 Gbps in

controlled test environment)Transfer of 25 GB file in approx 70 seconds.

FILE TRANSMISSION SPEED

USB 3.1

A faster transfer mode called "SuperSpeed+ USB 10 Gbit/s“.

New ERA of USB

Apple MacBook

USB On-the-Go (USB OTG)Connect two ‘peripherals’ togetherPC is not required (but still supported)

Allow two devices to exchange the host role

New OTG devices can tap into the existing 900 million USB devices

Advantages of a Universal Serial Bus:

Portable/convenientA large amount of information can be storedResistant to scratchesFits almost all devices that have a USB portHigh speed

BENEFITS OF USBEase of UseOne interface for many devices. Automatic configuration. Hot pluggable No power supply required

Any Questions