1、 外文原文（复印件）
A: Fundamentals of Single-chip Microcomputer
T h e sin gle -ch ip mi c ro co m p u t e r is t h e cu lm in at io n of b ot h t h e d e ve lo p me nt of t h e d ig ita l co m p u t e r a n d t h e i nte g rated c ircu it a rgu ab l y t h e to w mo st s ign if i cant i nve nt i o n s of t h e 20t h c e nt u ry [1].
T h e to w t yp e s of arch ite ct u re are fo u n d in s in gle -ch ip m i cro co m p u te r. S o m e e mp l oy t h e sp l it p ro gra m /d at a m e m o r y of t h e H a r va rd arch ite ct u re , s h o wn in -5A , ot h e rs fo l lo w t h e p h i lo so p hy, wid e l y ad a p ted fo r ge n e ral -p u rp o co m p u te rs an d m i cro p ro ce ss o rs , of m a kin g n o l o g i ca l d i st in ct i o n b et we e n p ro gra m an d d ata m e m o r y as in t h e P rin c eto n a rch ite ct u re , sh o wn in -5A.
In ge n e ra l te r m s a s in g le -ch ip m ic ro co m p u t e r is ch a ra cte r ized b y t h e in co r p o rat io n of all t h e u n its of a co mp u te r into a s in gle d e vi ce , as s h o w n in F i g3-5A-3.
-5A-1
A Harvard type
-5A. A conventional Princeton computer
Program
memory Data
memory CPU Input& Output unit
memory
CPU Input& Output unit
Ret
Interrupts
Power
Fig3-5A-3. Principal features of a microcomputer
Read only memory (ROM).RO M is u su a l l y fo r t h e p e r m an e nt , n o n -vo lat i le sto rage
of an ap p l i cat io n s p ro g ram .M a ny m i c ro co m p u te rs a n d m i cro co nt ro l le rs are inte n d ed fo r h i gh -vo lu m e ap p l i cat io n s a n d h e n ce t h e e co n o m i cal man u fa c t u re of t h e d e vi ces re q u ires t h at t h e co nt e nts of t h e p ro gra m me mo r y b e co mm i ed p e r m a n e nt l y d u r in g t h e m a n u fa ct u re of c h ip s . C lea rl y, t h i s imp l ies a r i go ro u s ap p ro a ch to ROM co d e d e ve lo p m e nt s in ce ch an ges can n o t b e mad e af te r m an u fa ct u re .T h i s d e ve l o p m e nt p ro ces s m ay i nvo l ve e mu l at i o n u sin g a so p h ist icated d e ve lo p m e nt syste m wit h a h ard wa re e mu l at i o n capab i l it y as we ll as t h e u s e of p o we rf u l sof t war e to o l s.
So m e m an u fa ct u re rs p ro vi d e ad d it i o n a l ROM o p t io n s b y in clu d in g in t h e i r ran ge d e v ic es w it h (o r inte n d ed fo r u s e wit h ) u r p ro g ram m a b le m e mo r y. T h e s im p lest of t h e i s u su a l l y d e v i ce wh i ch can o p e rat e in a m i cro p ro ce s so r mo d e b y u s in g s o m e of t h e in p u t /o u t p u t l in es as an ad d res s a n d d ata b u s fo r a cc es sin g exte rn a l m e m o r y. T h is t yp e o f d e vi ce can b e h ave f u n ct i o n al l y as t h e s in gle ch ip m i cro co m p u t e r f ro m wh i ch it i s d e ri ved a lb e it wit h re st r icted I/O an d a m o d if ied exte rn a l c ircu it. T h e u s e of t h e RO M le ss d e vi ces i s co mmo n e ve n in p ro d u ct io n circu i ts wh e re t h e vo lu m e d o e s n ot ju st if y t h e d e
ve lo p m e nt co sts of cu sto m o n -ch ip ROM [2];t h e re ca n st i ll b e a si gn if i cant sav in g in I/O an d o t h e r ch ip s co m pared to a External Timing components System clock Timer/ Counter Serial I/O Prarallel I/O RAM ROM
CPU
co nve nt io n al m i c ro p ro ces so r b ad circ u it. M o re exa ct re p l a ce m e nt fo r
RO M d e v ice s can b e o b tain ed in t h e fo rm of va ria nts w it h 'p i g g y-b a c k'
E P ROM(E rasab le p ro gramm ab le ROM )s o cket s o r d e v ice s w it h E P ROM
in stead of ROM 。T h e d e vi ces are n at u ra ll y m o re exp e n si ve t h a n
e q u iva le nt ROM d e v i ce, b u t d o p ro vid e co m p l ete c ircu it e q u iva le nt s.
E P ROM b ad d e vi ce s are a l so ext re m e ly a ra ct ive fo r lo w-vo lu m e
a p p li cat i o n s wh e re t h e y p ro vid e t h e ad vanta ges of a sin gl e-ch ip d e vi ce, in te rm s of o n-ch ip I/O, etc. ,wit h t h e co nve n ie n ce of f l ex i
b l e u s e r
p ro gra mm ab i lit y.
Random access memory (RAM).R A M is fo r t h e sto ra ge of wo r k in g
vari ab le s an d d ata u s ed d u r in g p ro gra m exe c u t io n. T h e s ize o f t h i s m e m o r y varie s wit h d e v ic e t yp e b u t it h as t h e s a m e ch ara cte ri st i c wid t h (4,8,16 b i ts e tc.) as t h e p ro ce ss o r ,S p e c ia l f u n ct io n re gi ste rs, su ch a s sta c k p o i nte r o r t i me r re g ist e r a re of t e n lo gi ca l ly in co r p o rated into t h e RAM a re a. It is a l so co mmo n in Ha rard t yp e mi c ro co m p u t e rs t o t re at t h e RAM area a s a
co lle ct io n of re g iste r; it i s u n n e ces sa ry to m a ke d ist in ct io n b et we e n RA M a n d p ro ce s so r r e g iste r as i s d o n e in t h e cas e of a m ic ro p ro ce sso r syste m
s in ce RAM an d r e gist e rs a re n ot u su al ly p hysi ca ll y p a rated in a
m i cro co m p u te r .
Central processing unit (CPU).T h e CP U i s m u ch l i ke t h at of any
m i cro p ro ce s so r. M any a p p li cat i o n s of m i cro co m p u te rs a n d mi c ro co nt ro lle rs i nvo l ve t h e h an d l in g of b in a r y-co d ed d e c im a l (BCD) d a ta (fo r n u m e ri ca l
d i sp lays, fo r exa mp l e) ,h
e n c e it is co m m o n to
村委会成员>编年体历史著作
f in d t h at t h e CP U is we l l
ad a p ted to h an d lin g t h i s t yp e of d ata .It i s a lso co m m o n to f in d go o d
fa c i l it ie s fo r test in g, s e in g a n d re in g in d i vid u a l b it s of m e m o r y o r I/O s in ce m any co nt ro ll e r ap p l i cat i o n s invo lve t h e t u rn in g o n a n d off of s in g le o u t p u t lin e s o r t h e read in g t h e sin gl e l in e. T h e lin e s are read i l y
i nte rfa ced t o t wo-state d e vi ce s su ch as s wit ch es, t h e rm o st at s, so l id-state re lays, val ve s, moto r, et c.
Parallel input/output. Pa ra lle l in p u t an d o u t p u t sc h e m es va r y
s o me wh at in d iffe re nt mi c ro co m p u te r; in m o st a m e ch an i sm i s p ro vi d ed to at le ast a llo w s o m e f l ex i b i lit y of ch o o sin g wh i ch p in s a re o u t p u ts an d wh ich a re in p u ts. T h is may ap p l y to a ll o r so m e of t h e p o r ts. S o m e I/O lin e s a re s u itab le fo r d ire ct i nte rfa c in g to, fo r exa m p le, f lu o res ce nt d i sp l ays, o r ca n p ro v id e suffi c ie nt cu r r e nt to m a ke inte r fa cin g ot h e r co m p o n e nts
st ra ight fo r ward. So m e d e v ice s allo w a n I/O p o rt to b e co nf i gu red as a syste m b u s to a llo w off-ch ip m e m o r y a n d I/O expan si o n. T h is fa c i l it y is
p ote nt ial l y u s ef u l as a p ro d u ct ra n ge d e ve lo p s, sin ce su c ce ss ive
e n h an ce me nts m ay b e co me t o o b i g fo r o n-ch ip m e m o r y an d it is
u n d e sirab l e n ot to b u i ld o n t h e exi st in g s of t ware b a.
Serial input/output .S e ri al co m m u n i cat i o n wit h t e rm in a l d e v i ces is
co mmo n me an s of p ro v id in g a lin k u s in g a sm a l l n u m b e r of lin e s. T h is so r t of co m m u n i cat io n can al so b e exp lo ited fo r inte rfa ci n g sp e c ia l f u n ct io n
c h ip s o r lin k in g ve ral mi c ro co m p u te rs t o get h e r .Bot h t h e co m m o n
a syn ch ro n o u s syn ch ro n o u s co m m u n i cat io n s ch e m e s re q u i re p rot o co l s t h at p ro v id e f ram in g (sta r t an d sto p) info rm at i o n .T h is ca n
b e im p l e m e nted a s a h ard wa re fa
c i lit y o r U(S)A RT(Un i ve rs al(syn ch ro n o u s) a syn ch ro n o u s
re ce i ve r/t ran smi e r) re l ie v in g t h e p ro ce sso r (a n d t h e ap p li cat i o n s
p ro gra mme r) of t h is lo w-le ve l, t im e-co n su m in g, d eta i l. t is m e re ly
n e ce ss a r y t o s e le cted a b au d-rate an d p o s si b l y ot h e r o p t i o n s (n u m b e r of sto p b i ts, pa rit y, etc.) an d lo ad (o r read f ro m) t h e r ial t ra n s m i e r (o r
re ce i ve r) b uffe r. S e r ia lizat i o n of t h e d at a in t h e a p p ro p riat e fo r m at is t h e n h an d led b y t h e h ard war e cir cu it.
Timing/counter facilities. M a ny ap p l icat io n of s in g le-ch ip
m i cro co m p u te rs re q u ire a c cu rate e va lu at io n of e lap d re a l t im e .T h is ca n b e d et
e rm in ed b y car ef u l as ss m e nt of t h e exe cu t i o n t im e of ea ch b ra n ch in a p ro gra m b u t t h i s rap id l y b e co m e s in effi c ie nt fo r a ll b u t si mp lest
p ro gra ms .T h e p r efe r red ap p ro ach i s to u t ime r circu it t h at ca n
in d e p e n d e nt l y co u nt p r e c is e t i m e i n cre m e nt s an d ge n e rat e a n inte r ru p t
a f te r a p res et t im e h as e l ap d .T h i s t y p e of t im e r is u su a ll y a r ran ged t o
b e re lo ad a b le w it h t h e r e q u ired co u nt .T h e t im e r t h e n d e cre m e nt s t h i s va lu e p ro d u cin g an inte r ru p t o r s e in g a f la g wh e n t h e co u nte r rea ch es ze ro.
B e e r t ime rs t h e n h ave t h e ab i lit y to au t o m at i ca ll y re l o a d t h e in it ia l co u nt valu e. T h i s re l ie ve s t h e p ro gram m e r of t h e resp o n s i b i l it y of re lo ad in g t h e co u nt e r an d as s sin g e lap d t im e b efo re t h e t im e r resta rted ,wh i ch
o t h e r wi wo u n d b e n e ce s sa r y if co nt in u o u s p re c is e l y t im ed inte rru p ts
we re re q u ired (as in a c lo c k ,fo r exa m p l e).S o m et im es asso ci ated wit h t im e r i s a n e ve nt co u nte r. W it h t h is fa c i lit y t h e r e i s u su a l l y a sp e c ia l in p u t
p i n ,t h at can d ri ve t h e co u nte r d ire ct ly.
Timing components. T h e clo c k circu it r y of m o st m i c ro co m p u te rs
re q u ires o n l y si m p le t im i n g co m p o n e nt s. If m ax im u m p e rfo rm an ce i s
re q u ired,a cr ystal m u st b e u d to e n s u re t h e m ax im u m c lo c k f re q u e n c y i s
a p p ro a ch ed
b u t n ot exce ed ed. M a ny cl o
c k c irc u it s a ls o wo r k wit h a res ist o r a n
d ca pa c ito r as lo w-co st t i min g co m p o n
锦鲤鱼品种e nts o r ca n b e d r i ve n
f ro m a n
将军岭
ex te rn a l so u rce. T h i s la e r ar ran ge m e nt is u f u l is exte rn a l
sy n ch ro n izat io n of t h e m i c ro co m p u te r is re q u ired.
WORDS AND TERMS
culmina on n.顶点
顶点
spilt adj.分离的
分离的生意祝福
vola le n. 易变的
易变的
commit v.保证
珍惜用英语怎么说保证
数学教育albeit conj.虽然
虽然
custom adj.定制的
定制的
variant adj.不同的
不同的
piggy-back adj.背负式的
背负式的
socket n. 插座
B:PLC[1]
P LC s (p ro gra mm a b le lo gi ca l co nt ro lle r) fa ce e ve r m o re co mp l ex
c h a lle n ge s t h es e
d ays . Wh
e re o n c e t h ey q u i et l y re p la ced re lays a n d gave a n o c ca sio n al re p o rt t o a co rp o rate m a in
f ram e, t h e y are n o w gro u p ed into c e ll s, gi ve n n e w jo b an d n e w l a n gu a ge s, a n d are fo rced to co m p ete a ga in st a
g ro win g a rray of co nt ro l p ro d u ct s. Fo r t
h
i s yea r's a n n u a l P LC te ch n o l o g y
u p d ate ,we q u e ried P LC ma ke rs o n t h es e to p i cs an d m o re .
Programming languages
H i gh e r le ve l P LC p ro gram m in g lan gu a ge s h a ve b e e n a ro u n d fo r s o m e
t i me ,b u t l ate l y t h e ir p o p u la rit y h as m u sh ro o m in g. "As R ay m o n d Le ve i l le,
v i ce p re sid e nt & ge n e ral ma n a ge r, S ie m e n s E n e rgy &Au to m at i o n .in c;
P ro gra mm ab le co nt ro l s are b e in g u d fo r m o re an d m o re so p h ist i cated
o p e rat io n s, lan gu ages o t h e r t h a n lad d e r lo gi c b e co m e m o re p ra ct i ca l,
effi cie nt, a n d p o we rf u l. Fo r exam p le, it's ve r y d iffi cu lt t o wr ite a
t r i go n o met ri c f u n ct i o n u sin g lad d e r lo gi c ."Lan gu a ge s ga in in g a c ce p ta n ce in c lu d e Bo o le an, co nt ro l syste m f lo wc h a r t in g, a n d su ch f u n ct i o n ch a r t
l an g u a ges as Grap h c e t an d it s va r i at io n .An d t h e re's in cre a sin g inte rest in l an g u a ges l i ke C an d BAS IC.
PLCs in process control
T h u s far, P LC s h ave n ot b e e n u d exte n si ve l y fo r co nt in u o u s p ro ces s
co nt ro l .W i ll t h i s co nt in u e "T h e fe e lin g t h at I've go e n," s ays Ke n J an n o a, m an ge r, p ro d u ct p lan n in g, r ies On e an d Se rie s S ix p ro d u ct ,at GE Fa n u c
N o rt h A me r i ca ,'is t h at P LC s w i ll b e u d in t h e p ro ce s s in d u st r y b u t n ot
n e ce ss a r i l y fo r p ro c es s co nt ro l."
Se ve ral ve n d o rs -o b v io u sl y b e in g t h at t h e o p p o s ite wi ll h a p p e n -h ave i nt ro d u ced P LC s o pt i mized fo r p ro ces s ap p l icat i o n .R i ch Rya n, ma n ge r,
co mme rci al ma r ket in g, A lle n-b rad l ey P ro gra m m a b le C o nt ro l s D iv., c ites
P LC s's in cre as in g u s e su ch in d u st r ie s a s fo o d ,ch e m i ca l s ,an d p et ro l e u m. Rya n fe e ls t h e re are t wo t yp es of ap p li cat i o n s in wh i ch t h ey're a p p ro p riat e. "o n e," h e says," is w h e re t h e s ize of t h e p ro ce s s co nt ro l syste m t h at's b e in g a u t o m ated d o esn't ju st i f y D CS[d ist r i b u ted co nt ro l syste m].W it h t h e
st art i n g p ri ce ta g s of ch o p ro d u c ts b e in g re l at i ve ly h i gh, a p ro gra m m a b le co nt ro lle r m ake s n fo r sm a ll, lo w lo o p co u nt a p p li cat i o n .T h e s e co n d i s w h e re yo u h ave to i nte g rate t h e l o o p c lo l y wit h t h e s e q u e nt ia l
l o g i ca l .B atch co nt ro lle rs ar e p ri m e exa m p l e ,wh e re t h e q u e n c e a n d
隋炀帝开凿大运河
m aint ain i n g t h e p ro ce ss var ia b le a re inte r t win ed so cl o ly t h at t h e
b e n ef it s of h av in g a p ro gram m ab le co nt ro lle r to d o t h e q u e nt i a l lo g i ca l
o u t we i gh s so me of t h e d i sad vant a ge s of n ot h avin g a d ist r i b u ted co nt ro l syste m."
