ａｎd ｌｏwer lim ｉｔ value ． Ｂy d ｏi ｎg so it is to kee ｐ the ｔem ｐe ｒａ
ture unchanｇed. Ｔhe sｙstｅm iｓ of high antｉ-jamminｇ， hｉgｈ contrｏｌ ｐ
reciｓｉon ａnd flｅxible ｄesigｎ; ｉt aｌso fits the ｒugged envirｏｎment。 Ｉ
t is ｍainlｙ used in ｐeoplｅ＇s lifｅ to ｉmprｏve ｔｈe quａｌｉty of ｔhｅ ｗ
ｏrk ａnd life。 Iｔ is aｌｓo ｖersaｔile, so that ｉt can ｂe conｖenienｔ to exｔ
end tｈe use oｆ the system。 So the design iｓ of profoｕnｄ ｉｍｐortance. Ｔｈ
e ｇｅneral dｅsigｎ， haｒdｗａｒe desiｇn anｄ software design oｆ thｅ sｙ
stem arｅ covered。
1.1 Iｎtｒoduｃtion
Tｈｅ 8—ｂit AT８９C51 CHMOS microcontｒｏｌlｅｒs are designed to hanｄ
le high-spee ｄ calc ｕ lations ａ n ｄ ｆａ st inp ｕ t/ ｏ utpu ｔ ｏ ｐ ｅ rat ｉ ons. Ｍ
CS 51 miｃｒｏcoｎtｒollers are typｉｃaｌｌy usｅｄ ｆor ｈigh-speed eveｎt c
ｏ ntrol sy ｓ tem ｓ 。 C ｏ ｍ mercial ａ pp ｌ icati ｏ n ｓ incl ｕ de mo ｄ em ｓ ，
motor—contrｏl syｓｔｅmｓ， printeｒｓ, phoｔocopiｅｒs, aiｒ condiｔionｅ
r c ｏ ｎtro ｌ s ｙ ｓt ｅm ｓ, ｄ ｉsk d ｒｉ ｖｅ s, and m ｅ dic ａ l instr ｕmen ｔ
s. The a ｕ t ｏ mo ｔ ｉ ve in ｄ ustry ｕs ｅ MCS 51 m ｉ cr ｏ co ｎ tro ｌ ｌ ｅ ｒｓ
in engine-con ｔ rol ｓ yste ｍ s, ai ｒ b ａ ｇ s ， ｓ ｕ spen ｓ i ｏ n sys ｔ em ｓ ，
and antilo ｃ k braki ｎ g s ｙ st ｅ ｍ s ( Ａ Ｂ S) 。 The AT89 Ｃ 5 １ is ｅ sp ｅ ci ａ
lly well suiｔed ｔo ａpplicatioｎs that benefit fr ｏm its pr ｏces ｓｉ ng sp ｅeｄ
and ｅ n ｈ a ｎ ced on—chip ｐ e ｒ ipheral fun ｃ ｔ ｉ o ｎ s set, such as automot ｉ
ve poｗｅr-ｔrａin control， vehiｃle dynａmic sｕspensｉｏn, anｔiｌocｋ ｂrak
ｉ n ｇ ， ａ ｎ d s ｔ abi ｌ i ｔ ｙ ｃ ont ｒ ol appli ｃ ａ ti ｏ ns 。 Because o ｆ t ｈ
ese criticaｌ applicaｔioｎｓ， the mａrket ｒeqｕires a reliａble cosｔ-effectｉve
ｃｏntroller wｉｔh a ｌｏw inteｒrupt latency ｒesｐonse， abｉlitｙ tｏ ｓｅ
rvice ｔhe high nｕｍｂer of ｔime ａnd eｖenｔ driveｎ integｒａtｅd ｐeripheｒ
als needed i ｎ real ti ｍ e ap ｐ l ｉ ca ｔ io ｎ ｓ ， ａ n ｄ ａ
CPU with above average processing ｐｏwer in a siｎglｅ packagｅ。 Ｔhe ｆｉn
ａnciａl ａnd legal rｉsk of having ｄevｉceｓ thaｔ operａｔe uｎpreｄｉctabｌ
y ｉｓ veｒy hｉgh. Onｃe in the market， particulaｒly iｎ misｓｉon crｉticaｌ
ａｐplicatioｎs sｕch as an ａｕtｏpilｏt oｒ antｉ-loｃk bｒaking ｓystｅm，
mistakeｓ arｅ ｆｉnａnciａllｙ prohiｂitｉve。 Ｒedｅsiｇn cosｔs ｃan run aｓ
high aｓ a ＄5００K, ｍuch more iｆ the fix meａnｓ 2 back annｏtatｉng it acｒo
ｓs a ｐｒｏdｕct famｉly ｔhat share the ｓamｅ core ａnｄ／or peｒiphｅｒａ
ｌ ｄesign flaw。 In addition， fieｌd rｅplaｃeｍenｔs of cｏmponｅnts iｓ ｅ
xtreｍeｌy exｐensiｖe， aｓ the devices ａrｅ tyｐically sealed ｉn moduleｓ wi
ｔｈ ａ ｔｏｔal value ｓeveral times ｔhat ｏf the coｍｐoneｎt。 Ｔo ｍitigaｔ
