CSM51Ach5

CSM51Ach5 - Chap ter D es igno fcom b inat iona l sy stem s...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chap ter D es igno fcom b inat iona l sy stem s :tw o-leve lgate netw ork s Inth ischap terw ep resen t D es igno ftw o-leve lgatenetw ork s : and- or and or- and netw ork s . M in im a ltw o-leve lnetw ork s .K arnaughm ap s .M in im izat ionp rocedu re andtoo ls .L im itat ion so ftw o-leve lnetw ork s . D es igno ftw o-leve l nand- nand and nor- nor netw ork s . P rogramm ab lelog ic : pla sand pal s . Thedes igno fagatenetw ork isthep rocesso fob ta in inganetw orkthat im p lem en tsag iven funct iona lspec icat ionandsat isessom eadd it iona lcon- stra in ts ,suchasde layandnum bero fgates .Inth ischap ter ,w ep resen td irect m ethod sforthedes igno fs im p lenetw ork s .C om p lexnetw ork srequ ireah ier- arch ica l(m odu lar)app roach ,wh ich isd iscu ssed in laterchap ters . W ebeg indescr ib ingthedes igno ftw o-leve lgatenetw ork s ,forwh ichthereis aw e ll-denedsy stem at icp rocedu re .InChap terw econ s iderthem oregenera l caseo fm u lt ileve lnetw ork s ,forwh ichthedes ignp rocedu reissom ewhatless sy stem at ic . A nycom b inat iona lsy stem canbeim p lem en tedbyanetw ork form edbyone leve lo f not gates ,as econd leve lo f and gates ,andath ird leve lo f or gates . Th isim p lem en tat ionresu ltsfrom thefactthatanysw itch ingfunct ioncanbe rep resen tedbyasum o fp roducts(SP ) ,andth isexp ress ion iscom posedo fthe fo llow inge lem en ts : C hap ter.D esigno fcom b ina tiona lsystem s:tw o- leve lga tene tw orks i)L itera ls(uncom p lem en tedandcom p lem en tedvar iab les) .Theleve lo f not gatesinthenetw ork isu sedtoob ta inthecom p lem en tedvar iab leswhen- evertheyarenotava ilab leasex terna linpu ts . ii)P roducts ,wh ichareim p lem en tedbytheleve lo f and gates . iii)Sum ,im p lem en tedbyone or gate . Ifthenetw orkhassevera lou tpu ts ,one or gateisu sed foreachou tpu t ;the ou tpu tfrom not and and gatescanbesharedasinpu tstothe or gates . Inanana logou sfash ion ,an etw orkform edbyoneleve lo f not gates ,one leve lo f or gates ,andone and gateisob ta ined from ap roducto fsum s . Exam p le. C on s idertheim p lem en tat iono fam odu lo-increm enterwhose h igh-leve lspec icat ion is Inpu t : x O u tpu t : z Funct ion : z = ( x +)m od Ab inaryspec icat ionisob ta inedbycod ingthevar iab les x and z onb it- vectors x and z ,respect ive ly .W eu searad ix-rep resen tat iono fin tegers ,so thattheb itvectorshaves ixb itseach .Thetab lethatdescr ibesth isspec icat ion issom ewhatlargesow eg ivethesum o fp roductsd irect ly .Th iscanbeach ieved bynot ingthat z i iswhenever x i isandatleastoneo ftheless-s ign icant b itso f x is,orwhen x i =anda llless-s ign icantb itso f x are.Th isis illu stratedbythefo llow ingcases : x z x z Thespec icat ion isthen z = if x = otherw ise and for i> z i = < : if ( x i = and thereex ists j< i suchthat x j =) or ( x i = and x j =fora ll j< i ) otherw ise Thecorrespond ingexp ress ion sare z = x ( x x x x x ) xxxxxx = xx xx xx xx xx xxxxxx z 5 x 5 x' 4 x' 3 x' 2 x' 1 x' x 4 x' 5 x 3 x 2 x...
View Full Document

Page1 / 42

CSM51Ach5 - Chap ter D es igno fcom b inat iona l sy stem s...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online