The Ｉ nt ｒ oduc ｔ ion ｏｆ AT89 Ｃ 51Des ｃ r ｉ pti ｏ nＴhe ＡＴ89C51 iｓ ａ lｏw—pｏｗｅr， ｈｉgｈ－peｒforｍａｎcｅ CMＯS ８—bit ｍicｒoputer witｈ 4K bytes of Flａｓh proｇrammabｌｅ ａnｄ eraｓable reaｄ only memory (PEROM)、 Ｔｈe dｅｖiｃｅ ｉs manuｆａctuｒｅd using Atmｅl’s ｈｉｇh-density ｎonvolatile memorｙ technoｌogｙ and iｓ ｐaｔible ｗiｔｈ ｔhｅ inｄｕstry-staｎdard MＣS—5１ insｔruction sｅt、 The oｎ—chｉp Flash aｌlows the ｐroｇram meｍory tｏ be reproｇrａmmed in-syｓteｍ ｏr by ａ cｏnｖentional nｏnvolaｔilｅ mｅmorｙ progｒammer、 By ｂining a versatｉｌe 8—bｉt CPU wｉth Fｌａsh on a moｎolｉthic chip, thｅ Atmel ＡＴ89C51 ｉs a ｐoｗerful micｒｏpｕter wｈich proviｄｅs a highly—fleｘｉble ａnｄ ｃosｔ－eｆfective solｕtion to ｍaｎy eｍｂedded controｌ applｉｃations、Fu ｎｃ tion ch ａ ra ｃ ter ｉ s ｔ icThe ＡT89C５1 pｒｏvidｅs tｈｅ folｌowing sｔａndard featuｒes: 4K bytes of Ｆｌａsh, １28 bytｅｓ of RAＭ, 32 I/O lines, tｗo 16—biｔ timer/ｃoｕnｔerｓ， onｅ 5 vector two—lｅｖel inteｒrupt arｃhitecturｅ, a ｆulｌ duplｅｘ sｅriａｌ ｐort， one—chｉp osｃiｌlator anｄ clock cｉrｃｕｉtｒy、 Ｉn additｉｏn, the AT８9C5１ ｉs dｅsignｅd with statｉc logｉc ｆｏr operａtioｎ doｗn to zero freｑuｅncy and supporｔs ｔwo soｆｔware selectａbｌe pｏweｒ saｖing ｍodｅs、 Tｈe Idｌe Ｍｏde sｔｏps ｔhe ＣＰU ｗhile allｏｗing thｅ RAM， timｅr/counｔers, seｒial pｏrt and inteｒrupｔ system to continue fｕｎctioniｎg、 Thｅ Powｅr—down Modｅ saves ｔhe ＲAM cｏntenｔs but freｅzｅs the oｓcilｌator disabliｎg aｌl otheｒ chip functioｎs ｕntil ｔhe next haｒdwａrｅ reｓet、Pin D ｅ s ｃｒｉ ptio ｎVCC:Supply voltａge、GＮD:Gｒounｄ、P ｏ rt ０Pｏrt 0 ｉs an 8-bit ｏpen－drain ｂi—ｄｉrecｔiｏ...
