自动化专业可参考的外文文献.docx

自动化专业可参考的外文文献.docx

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自动化专业可参考的外文文献

1外文原文

A:

FundamentalsofSingle-chipMicrocomputer

Thesingle-chipmicrocomputeristhedevelopmentofthedigitalcomputeranarguablythetowmostsignificantinventionsofthe20thcentury[1].

Thesetowtypesofarchitecturearefoundinsingle-chipmicrocomputer.Someemploythesplitprogram/datamemoryofthe

Harvardarchitecture,showninFig.3-5A-1,othersfollowthe

philosophy,widelyadaptedforgeneral-purposecomputersand

microprocessors,ofmakingnologicaldistinctionbetweenprogram

anddatamemoryasinthePrincetonarchitecture,showninFig.3-5A-2.

Ingeneraltermsasingle-chipmicrocomputeris

characterizedbytheincorporationofalltheunitsofacomputer

intoasingledevice,asshowninFig3-5A-3.

Fig.3-5A-1AHarvardtype

Fig.3-5A-2.AconventionalPrincetoncomputer

Fig3-5A-3.Principalfeaturesofamicrocomputer

Readonlymemory（ROM）.ROMisusuallyforthepermanent,

non-volatilestorageofanapplicationsprogram.Many

microcomputersandmicrocontrollersareintendedforhigh-volume

applicationsandhencetheeconomicalmanufactureofthedevices

requiresthatthecontentsoftheprogrammemorybecommitted

permanentlyduringthemanufactureofchips.Clearly,thisimpliesarigorousapproachtoROMcodedevelopmentsincechangescannotbemadeaftermanufacture.Thisdevelopmentprocessmayinvolveemulationusingasophisticateddevelopmentsystemwithahardwareemulationcapabilityaswellastheuseofpowerfulsoftwaretools.

SomemanufacturersprovideadditionalROMoptionsbyincludingintheirrangedeviceswith（orintendedforusewith）

userprogramnablememory.Thesimplestoftheseisusuallydevice

whichcanoperateinamicroprocessormodebyusingsomeofthe

input/outputlinesasanaddressanddatabusforaccessingexternal

memory.Thistypeofdevicecanbehavefunctionallyasthesinglechipmicrocomputerfromwhichitisderivedalbeitwithrestricted

I/Oandamodifiedexternalcircuit.TheuseoftheseROMless

devicesiscommoneveninproductioncircuitswherethevolumedoes

notjustifythedevelopmentcostsofcustomon-chipROM[2];there

I/

conventionalmicroprocessorbasedacementforROMdevicescanbeobtaipiggy-swit

canstillbeasignificantsavingintoareplwithdevi

Oandotherchipscomparedcircunedinammabl

ce

progr

Thesedevic

it.MoreexacttheformofvaeROM

esare

）socketsnaturall

riants

ymore

expensive

th

aneq

uival

ent

ROMdev

ice

J

bu

tdo

p

rov

idecompl

ete

circuiteq

ui

valen

ts.E

PROMbased

devic

es

are

a

lso

extremel

y

attractive

f

orlo

w-vol

ume

applica

tio

ns

w

here

t

hey

provide

the

advantages

o

fas

ingle

-chi

pdevic

e,

in

t

ermso

fo

n-chipI/

O,

etc.,with

t

heco

nveni

ence

offle

xib

le

u

ser

progr

amnabilit

y.

back'EPROM（ErasableEPROMinsteadofROM。

Randomaccessmemory（RAM）.

RAM

fo

the

stora

ge

ofw

or

king

variable

memoryvawidtregilogiHaraofr

ut

hesamech,Specialregister

Itisa

size

aracteristicfunctionareoftensocommoninacollectionetweenRAMandsystemdina

grahdevicetypebutithasetc.）as

sstackpoiratedintocomputerstounnecessar

sanddatauseddurinri

8

gpro

mexecst

ion.T

he

ofthis

eswit,16bitsuchaincorpo

h（4stercallyrdtypemicroegister;itis

s,

thep

nter

theR

tre

rocessorortimerAMarea.

attheRAMareaas

ytomakedistinctionb

inthecaseofamicroprocessorparate

processorregisterasisdonesinceRAMandregistersarenotusuallyphysicallysemicr

ocomputer.

Centralprocessingunit（CPU）.

TheCPUismuchl

iketh

atof

anymicrdata（ffindtisals

microprocessor.Manyapplicatocontrollersinvolvethehandlornumericaldisplays,forhattheCPUiswelladaptedtndgoodfacil

onsofngofbixample

resettapplorttotrela

o

in

at

ichewo-stateys,valv

re

commontofigindividualions

adin

invoIvegthesidevicessuches,motor,etc.

Parallel

ohandlitiesf

bitsofmemoryorthetungleli

ersand

nary-codeddecimal（BCD）itiscommontotypeofdag,settinmanycont

microcomput

）,henee

ingthis

ortestin

input/output.

somewhatin

providedtoatleastalareoutputsandwhichatheports.SomeI/Olinfor

different

currdevioff-

example,fluoenttomakeincesallowanIchipmemorya

rningonandne.Theseliasswitches,

Parallel

micr

lowsomereinputesar

rescentterfaci/Oportnd1/O

in

i

il

ta.Itgandroller

lines

I/Osince

offofsi

nesarereadilyinterfacedthermostats,solid-state

ngleoutput

putandoutputschemesvary

ocomputer;

flexib

s.Thismayapplytoallornterfasuffic

nmostamechanismiityofchoosingwh

ic

uitablefordirectiays,orcanprovideraig

esdisplngothercomponentssttobeconfiguredasasystexpansion.Thisfacility

s

ci

ie

s

hpinsomeofngto,nt

htforward.Someembustoallowispotentially

usefulasaproductramaybecometoobigforbuil

dontheexisting

Serialinput/output

ncesuccessiveenhancementstto

ngedevelops,si

on-chipmemoryanditisundesir

se.

ableno

soft

wareba

.Serial

communicationw

itht

ermin

al

devioflintemicr

cesiscommonmeansofines.Thissorfacingspeciocomputersto

comnun（stafaci

rtliivic

icatandtyoer/tatio

providrtofcommunialfunctioncgether.Bothtemesrenformat

cat

hip

he

ingalinkusingioncanalssorli

obe

nkin

asmexploeral

allnuitedfor

mber

ionschstop）irU（S）ART（Univransmitter）rensprogrammer）

quio

receappltismerelynecessaroptionstheseridataci

rc

inuit.

（n

al

th

umberofst

transmitt

eappropri

mi

i

i

ttiii

iren.Tsal（evin

pro

his

common

tocols

canbe

gsevchronoussyprovidef

asynthat

implementedasahardware

nchronousraming

er

li

ofthi

chronous）asynchronousheprocessor（andthe

syn

gt

slow-level,time-consuming,detail.

ytoselectedabaud-rateandpossiblyotheropbiter（oratefo

Timing/counterfacilities.

cr

me.Thiscanmeofeachb

ocomputers

s,parity,etc.）anreceiver）buffer.rmatisthenhandl

requireaccurateebedeterminedbycarranchinarallbuts

nefficientfo

stousetimercircuittncrementsandgenerate

programimplestphatcaninaninterr

elapsed.Thistypeoftimerisuswiththerequiredproducinganintezero.Bettertimetheinitialresponsibilibeforethetcontinclockcountepin,t

uousp

fore

r.Wit

Manyapplic

valuationoefulassessbutthisra

dload（orreadfrom）Serializationoftheedby

ation

the

ofs

hardware

ingle-chip

fela

mentoftheexecutionpidlybecomes

psed

real

rograms.Thepreferredapproachdependentlycountprecisetimeuptual

afterapresettimehaslyarhen

agwhenthecounterre

litytoautomaticallyre

rangedtobereloadabledecrementsthisvalueachesload

count.Thet

■ruptorsett

■sthenhavet

value.Thisreloadingthecostarted,whichtimedSometiacilthe

counttyofimerre

imerting

he

rel

reciselyxample）.hthisf

int

err

it

hatcandrive

co

mesythunte

ass

ererd

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abi

ievestheprogrammeroftheunterandassessingelapsedtimeoth

upt

oci

is

ire

erwisewoundbenecessaryifed（asinaer

s

at

u

ct

wereedwal

su

ly.

r

it

ly

equirhtim

asp

is

anevent

ecialinput

Timingcomponents.Theclock

circuit

ry

ofmost

microcomputers

requiresonlysimpletimingcomponents.Ifrequired,acrystalmustbeusedtfrequencyisapproachedbutnotexworkwitharorcanbedriisuseful

maximumperformaneeisethemaximumclock

esistorandcapacitovenfromanexternalisexternaIsynchroniza

oensur

ceeded.Manyclockcircuitsalsoraslow-costtisource.Thisla

mngcomponents

tterarrangement

tionofthemicrocomputeris

required.

WORDSANDTERMS

culminationn.顶点spiltadj.分离的volatilen.易变的

commitv.保证albeitconj.虽然

customadj.定制的variantadj.不同的piggy-backadj.背负式的socketn.插座

B:

PLC[1]

PLCs（programmablelogicalcontroller）faceevermorecomplexchallengesthesedays.Whereoncetheyquietlyreplaced