Uni

vers

ity o

f Pun

e S.

E. I.

T.

Subj

ect c

ode:

214

442

Part

35

: Uni

vers

al S

eria

l Bus

Com

pute

r Org

aniz

atio

n

UN

IT

V

Tush

ar B

. Kut

e,

Dep

artm

ent o

f Inf

orm

atio

n Te

chno

logy

, Sa

ndip

Inst

itute

of T

echn

olog

y &

Res

earc

h Ce

ntre

, Nas

hik.

ht

tp:/

/tus

hark

ute.

com

USB

U

nive

rsal

Ser

ial B

us (U

SB) i

s a sp

ecifi

catio

n to

est

ablis

h co

mm

unic

atio

n be

twee

n de

vice

s and

a h

ost c

ontr

olle

r (us

ually

pe

rson

al c

ompu

ters

), de

velo

ped

and

inve

nted

by

Ajay

Bha

tt w

hile

w

orki

ng fo

r Int

el.

USB

is in

tend

ed to

repl

ace

man

y va

rietie

s of s

eria

l and

par

alle

l por

ts.

USB

can

con

nect

com

pute

r per

iphe

rals

such

as m

ice,

key

boar

ds,

digi

tal c

amer

as, p

rinte

rs, p

erso

nal m

edia

pla

yers

, fla

sh d

rives

, N

etw

ork

Adap

ters

, and

ext

erna

l har

d dr

ives

. Fo

r man

y of

thos

e de

vice

s, U

SB h

as b

ecom

e th

e st

anda

rd co

nnec

tion

met

hod.

USB

was

des

igne

d fo

r per

sona

l com

pute

rs, b

ut it

has

be

com

e co

mm

onpl

ace

on o

ther

dev

ices

such

as s

mar

tpho

nes,

PDA

s an

d vi

deo

gam

e co

nsol

es, a

nd a

s a p

ower

cord

. As o

f 200

8, th

ere

are

abou

t 2 b

illio

n U

SB d

evic

es so

ld p

er y

ear,

and

appr

oxim

atel

y 6

billi

on

tota

l sol

d to

dat

e.

So

urce

: Wik

iped

ia fr

ee e

ncyc

lopa

edia

.

Hist

oric

al B

ackg

roun

d-1

The

Uni

vers

al S

eria

l Bus

(USB

) is a

stan

dard

for p

erip

hera

l de

vice

s. It

beg

an d

evel

opm

ent i

n 19

94 b

y a

grou

p of

se

ven

com

pani

es: C

ompa

q, D

EC, I

BM, I

ntel

, Mic

roso

ft,

NEC

and

Nor

tel.

U

SB w

as in

tend

ed to

mak

e it

fund

amen

tally

eas

ier t

o co

nnec

t ext

erna

l dev

ices

to P

Cs b

y re

plac

ing

the

mul

titud

e of

con

nect

ors a

t the

bac

k of

PCs

, add

ress

ing

the

usab

ility

issu

es o

f exi

stin

g in

terf

aces

, and

sim

plify

ing

soft

war

e co

nfig

urat

ion

of a

ll de

vice

s con

nect

ed to

USB

, as

wel

l as p

erm

ittin

g gr

eate

r ban

dwid

ths f

or e

xter

nal

devi

ces.

The

firs

t sili

con

for U

SB w

as m

ade

avai

labl

e by

In

tel i

n 19

95

Hist

oric

al B

ackg

roun

d-2

The

USB

1.0

spec

ifica

tion

was

intr

oduc

ed in

Janu

ary

1996

. The

orig

inal

USB

1.0

spec

ifica

tion

had

a da

ta

tran

sfer

rate

of 1

2 M

bit/

s.

The

first

wid

ely

used

ver

sion

of U

SB w

as 1

.1, w

hich

w

as re

leas

ed in

Sep

tem

ber 1

998.

It a

llow

ed fo

r a 1

2 M

bit/

s dat

a ra

te fo

r hig

her-

spee

d de

vice

s suc

h as

di

sk d

rives

, and

a lo

wer

1.5

Mbi

t/s r

ate

for l

ow

band

wid

th d

evic

es su

ch a

s joy

stic

ks.

Hist

oric

al B

ackg

roun

d-3

The

USB

2.0

spec

ifica

tion

was

rele

ased

in A

pril

2000

an

d w

as st

anda

rdize

d by

the

USB

-IF a

t the

end

of

2001

. He

wle

tt-P

acka

rd, I

ntel

, Luc

ent T

echn

olog

ies (

now

Al

cate

l-Luc

ent f

ollo

win

g its

mer

ger w

ith A

lcat

el in

20

06),

NEC

and

Phi

lips j

oint

ly le

d th

e in

itiat

ive

to

deve

lop

a hi

gher

dat

a tr

ansf

er ra

te, w

ith th

e re

sulti

ng

spec

ifica

tion

achi

evin

g 48

0 M

bit/

s, a

fort

yfol

d in

crea

se o

ver 1

2 M

bit/

s for

the

orig

inal

USB

1.0

.

USB

feat

ures

Sim

ple

Conn

ectiv

ity.

Sim

ple

Cabl

es.

One

inte

rface

for m

any

devi

ces.

Au

tom

atic

Con

figur

atio

n.

No

user

set

ting.

Fr

ee h

ardw

are

reso

urce

s for

oth

er d

evic

es.

Hot P

lugg

able

.

USB

Con

nect

or

USB

Con

nect

ors

USB

3.0

USB

Dat

a

USB

dat

a sig

nals

are

bi-p

hase

sign

als.

U

sual

ly, IC

757

73 fr

om Te

xas i

nstr

umen

ts is

use

d as

bo

th th

e di

ffere

ntia

l lin

e dr

iver

and

rece

iver

. Th

e U

SB u

ses N

RZI (

Non

-Ret

urn

to Z

ero

Inve

rted

) da

ta e

ncod

ing

met

hod

for t

rans

mitt

ing

data

pac

kets

. In

this

met

hod,

the

signa

l lev

el d

oes n

ot c

hang

e fo

r th

e tr

ansm

issio

n of

logi

c 1. H

owev

er, i

t is i

nver

ted

for

each

cha

nge

to a

logi

c 0.

USB

inte

rfac

e us

ing

CMO

S bu

ffers

NRZ

I enc

odin

g sc

hem

e

Bit S

tuffi

ng

USB

Com

man

ds

Pack

et F

orm

ats

Data

Tra

nsfe

r Typ

es

Cont

rol T

rans

fer

Bulk

Tra

nsfe

r In

terr

upt T

rans

fer

Isoc

hron

ous

Tran

sfer

IEEE

488

Gen

eral

Pur

pose

Inte

rfac

e Bu

s

Talk

ers:

Cap

able

of p

uttin

g th

e da

ta o

n th

e bu

s fo

r tra

nsm

issio

n e.

g. ta

pe re

ader

s, d

igita

l vo

ltmet

ers,

freq

uenc

y co

unte

rs.

List

ener

s: C

apab

le o

f rea

ding

the

data

on

the

bus o

utpu

t by

talk

ers e

.g. p

rinte

rs, d

ispla

y de

vice

s.

Cont

rolle

rs: D

eter

min

es w

ho ta

lks a

nd w

ho

liste

ns o

n th

e bu

s e.g

. pro

gram

dev

ices

on

bus.

Refe

renc

es

Web

sites

: ht

tp:/

/en.

wik

iped

ia.o

rg

Com

pute

r Arc

hite

ctur

e an

d O

rgan

izatio

n

By A

. P. G

odse

(fro

m b

ooks

.goo

gle.

com

)

Com

pute

r Org

aniza

tion

By

Ham

ache

r and

Zak

y