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.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
afl
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
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