外文翻譯--pic系列單片機(jī)的特點(diǎn)

1、<p>　　PIC系列單片機(jī)的特點(diǎn)</p><p>　　隨著大規(guī)模集成電路（LSI）制造技術(shù)的飛速發(fā)展，電腦正朝著兩個明顯的方向（即兩大分支）發(fā)展：一是微型計算機(jī)系統(tǒng)的性能不斷提高，以滿足高速度大容量的"數(shù)據(jù)處理"；二是單片微機(jī)的功能日益完善，以滿足諸多領(lǐng)域各種錯綜復(fù)雜的"現(xiàn)場控制"。</p><p>　　在1975年德克薩斯儀器公司發(fā)明的

2、世界上第一個4位單片機(jī)TMS－1000誕生后，一些大型微電子公司競相研制開發(fā)了各種單片機(jī)系列產(chǎn)品。從字長方面劃分，單片機(jī)有4位、8位、16位、32位四大類，其中前三類占據(jù)了單片機(jī)市場的主要份額，在這三類單片機(jī)當(dāng)中，8位機(jī)又一直為主流產(chǎn)品。</p><p>　　較具有代表性的4位單片機(jī)有美國德克薩斯儀器公司的TMS－1000，日本電氣公司（NEC）的μPD75××系列，美國國家半導(dǎo)體公司（NS）

3、的COP400系列，美國洛克威爾公司（ROCKWELL）的PPS/1系列，日本松下公司的MN1400系列，日本富士通公司的MB88系列以及日本夏普公司的SM××系列等等。</p><p>　　較具有代表性的8位單片機(jī)有美國微芯片公司的PIC16C××系列、PIC17C××系列、PIC1400系列，美國英特爾公司的MCS－48和MCS－51系列，美國摩托羅

4、拉公司的MC68HC05系列和MC68HC11系列，美國齊洛格公司的Z8系列，日本電氣公司的μPD78××系列，美國莫斯特克公司和仙童公司合作生產(chǎn)的F8(3870)系列等。 較具有代表性的16位單片機(jī)有美國莫斯特克公司的MC68200，美國英特爾公司的MCS－96系列，日本電氣公司的μPC14040系列，美國國家半導(dǎo)體公司（NS）的783××系列等。</p><p>　　目

5、前，單片機(jī)正朝著片內(nèi)存儲器RAM和ROM容量大、I/O端口功能多、電源電壓范圍寬、功率消耗低、操作速度快的方向發(fā)展。</p><p>　　在上述各種單片機(jī)中，本講座為什么選用微芯片公司的PIC系列中的PIC16F873單片機(jī)作為樣板介紹呢?</p><p>　　PIC系列單片機(jī)的硬件系統(tǒng)設(shè)計簡潔，指令系統(tǒng)設(shè)計精煉。在所有的單片機(jī)品種當(dāng)中，它是最容易學(xué)習(xí)、最容易應(yīng)用的單片機(jī)品種之一。對于單片

6、機(jī)的初學(xué)者來說，若選擇PIC單片機(jī)作為攻入單片機(jī)王國的"突破口"，將是一條最輕松的捷徑，定會取得事半功倍的功效。目前已有好幾家著名半導(dǎo)體公司仿照PIC系列單片機(jī)，開發(fā)出與之引腳兼容的系列單片機(jī)，比如美國SCENIX公司的SX系列、臺灣EMC公司的EM78P系列、臺灣MDT公司的MDT系列等。 PIC系列單片機(jī)具有以下特點(diǎn)：（1）采用哈佛結(jié)構(gòu)。在國內(nèi)最常見的單片機(jī)中，PIC系列單片機(jī)是唯一一種在芯片內(nèi)部采用哈佛結(jié)構(gòu)的機(jī)

7、型。這里所說的"哈佛結(jié)構(gòu)"就是，在芯片內(nèi)部將數(shù)據(jù)總線和指令總線分離，并且采用不同的寬度。這樣做的好處是，便于實(shí)現(xiàn)"流水作業(yè)"，也就是在執(zhí)行一條指令的同時對下一條指令進(jìn)行取指操作，而在一般的單片機(jī)中，指令總線和數(shù)據(jù)總線是共用的。 </p><p>　?。?）指令的"單字節(jié)化"。因?yàn)閿?shù)據(jù)總線和指令總線是分離的，并且采用了不同的寬度，所以程序存儲器ROM和數(shù)據(jù)

8、存儲器RAM的尋址空間是互相獨(dú)立的，而且兩種存儲器寬度也不同。這樣設(shè)計不僅可以確保數(shù)據(jù)的安全性，還能提高運(yùn)行速度和實(shí)現(xiàn)全部指令的"單字節(jié)化"。在此所說的"字節(jié)"，特指PIC單片機(jī)的指令字節(jié)，而不是常說的8比特字節(jié)。例如，PIC12C50×/ PIC16C5×系列單片機(jī)的指令字節(jié)為12比特；PIC16C6×/ PIC16C7×/ PIC16C8×系列

9、的指令字節(jié)為14比特；PIC17C××系列的指令字節(jié)為16比特。它們的數(shù)據(jù)存儲器全為8位寬。而MCS－51系列單片機(jī)的ROM和RAM寬度都是8位，指令長度從1個字節(jié)（8位）到3個字節(jié)長短不一。 </p><p>　?。?）精簡指令集（RISC）技術(shù)。PIC系列單片機(jī)的指令系統(tǒng)只有35條指令。這給指令的學(xué)習(xí)、記憶、理解帶來很大的好處，也給程序的編寫、閱讀、調(diào)試、修改、交流帶來極大的便利，真可謂&

10、quot;易學(xué)好用"。而MCS－51單片機(jī)的指令系統(tǒng)共有111條指令，MC68HC05單片機(jī)的指令系統(tǒng)共有89條指令。PIC系列單片機(jī)不僅全部指令均為單字節(jié)指令，而且絕大多數(shù)指令為單周期指令，以利于提高執(zhí)行速度。</p><p>　　（4）尋址方式簡單。尋址方式就是尋找操作數(shù)的方法。PIC系列單片機(jī)只有4種尋址方式（即寄存器間接尋址、立即數(shù)尋址、直接尋址和位尋址，以后將作詳細(xì)解釋），容易掌握，而MCS－

11、51單片機(jī)則有7種尋址方式，68HC05單片機(jī)有6種。</p><p>　?。?）代碼壓縮率高。 1K字節(jié)的存儲器空間，對于像MCS－51這樣的單片機(jī)，大約只能存放600條指令，而對于PIC系列單片機(jī)則能夠存放多達(dá)1024條指令條數(shù)。從圖1中可以看出，與幾種典型的單片機(jī)相比，PIC16C5×是一種最節(jié)省程序存儲器空間的單片機(jī)。也就是說，完成相同功能的一段程序所占用的空間，MC68HC05是PIC16C5

12、×的2.24倍。</p><p>　?。?）運(yùn)行速度高。由于采用了哈佛總線結(jié)構(gòu)，又由于指令的讀取和執(zhí)行采用了流水作業(yè)方式，PIC系列單片機(jī)的運(yùn)行速度大大提高。從圖2中可以看出，PIC系列單片機(jī)的運(yùn)行速度遠(yuǎn)遠(yuǎn)高于其它相同檔次的單片機(jī)。在所有8位機(jī)中，PIC17C×是目前世界上速度最快的品種之一。</p><p>　　（7）功耗低。PIC系列單片機(jī)的功率消耗極低，有些型號的

13、單片機(jī)在4MHz時鐘下工作時耗電不超過2mA，在睡眠模式下低到1μA以下。</p><p>　?。?）驅(qū)動能力強(qiáng)。I/O端口驅(qū)動負(fù)載的能力較強(qiáng)，每個I/O引腳吸入和輸出電流的最大值可分別達(dá)到25mA和20mA，能夠直接驅(qū)動發(fā)光二極管、光電耦合器或者微型繼電器等。</p><p>　?。?）具備I2C 和SPI串行總線端口：PIC系列單片機(jī)的一些型號具備I2C 和SPI串行總線端口。I2C和

14、SPI分別是由PHILIPS和MOTOROLA公司發(fā)明的在芯片之間實(shí)現(xiàn)同步串行數(shù)據(jù)傳輸?shù)膬煞N串行總線技術(shù)。利用單片機(jī)串行總線端口可以方便靈活地擴(kuò)展一些必要的外圍器件。串行接口和串行總線的設(shè)置，不僅大大地簡化了單片機(jī)應(yīng)用系統(tǒng)的結(jié)構(gòu)，而且還極易形成產(chǎn)品電路的模塊化結(jié)構(gòu)。目前，松下、日立、索尼、夏普、長虹等公司都在其大屏幕彩電等產(chǎn)品中引入了I2C技術(shù)。</p><p>　?。?0）尋址空間設(shè)計簡潔。PIC系列單片機(jī)的程

15、序、堆棧、數(shù)據(jù)三者各自采用互相獨(dú)立的尋址（或地址編碼）空間，而且前兩者的地址安排不需要用戶操心，這會受到初學(xué)者的歡迎。而MC68HC05和MC68HC11單片機(jī)的尋址空間只有一個，編程時需要用戶對程序區(qū)、堆棧區(qū)、數(shù)據(jù)區(qū)和I/O端口所占用的地址空間作精心安排，這樣會給高手的設(shè)計上帶來靈活性，但是也會給初學(xué)者帶來一些麻煩。</p><p>　?。?1）外圍電路簡潔。PIC系列單片機(jī)片內(nèi)集成了上電復(fù)位電路、I/O引腳上

16、拉電路、看門狗定時器等，可以最大程度地減少或免用外圍器件，以便實(shí)現(xiàn)"純單片"應(yīng)用。這樣，不僅便于開發(fā)，而且還可節(jié)省用戶的電路板空間和制造成本。</p><p>　?。?2）開發(fā)方便。通常，業(yè)余條件下學(xué)習(xí)和應(yīng)用單片機(jī)，最大的障礙是實(shí)驗(yàn)開發(fā)設(shè)備昂貴，使許多初學(xué)者望而卻步。微芯片公司及其國內(nèi)多家代理商，為用戶的應(yīng)用開發(fā)提供了豐富多彩的硬件和軟件支持。有各種檔次的燒錄器（或稱編程器）和硬件仿真器出售，

17、其售價大約從500元到2000元不等。此外，微芯片公司還研制了多種版本的軟件仿真器和軟件綜合開發(fā)環(huán)境（MPLAB－IDE），為愛好者學(xué)習(xí)與實(shí)踐、應(yīng)用與開發(fā)的實(shí)際操練提供了極大的方便。對于PIC系列中任一款單片機(jī)的開發(fā)，都可以借助于一套免費(fèi)的軟件綜合開發(fā)環(huán)境實(shí)現(xiàn)程序編寫和模擬仿真，再用任何一種廉價的燒錄器完成程序燒寫，便形成一套經(jīng)濟(jì)實(shí)用的開發(fā)系統(tǒng)。它特別適合那些不想過多投資購置昂貴開發(fā)工具的初學(xué)者和業(yè)余愛好者。借助于這套廉價的開發(fā)系統(tǒng)，用

18、戶可以完成一些小型電子產(chǎn)品的研制開發(fā)。由此可見，對初級水平的自學(xué)者來說，PIC單片機(jī)是一種最為適合、最容易接近的單片機(jī)。</p><p>　?。?3）C語言編程。對于掌握了C語言的用戶，微芯片公司還為其提供了"C語言編譯程序"，這樣的用戶如果使用C語言這種高級語言進(jìn)行程序設(shè)計的話，還可以大大提高工作效率。</p><p>　?。?4）品種豐富。PIC系列單片機(jī)目前已形成

19、三個層次、50多個型號。片內(nèi)功能從簡單到復(fù)雜，封裝形式從8腳到68腳，可以滿足各種不同的應(yīng)用需求。用戶總能在其中找到一款適合自己開發(fā)目標(biāo)的單片機(jī)。在封裝形式多樣化方面，不像MCS－51系列單片機(jī)那樣，大都采用40腳封裝，應(yīng)用靈活性受到極大的限制。此外，微芯片公司最先開發(fā)出世界上第一個最小的8腳封裝的單片機(jī)。</p><p>　　（15）規(guī)格齊全。微芯片公司對其單片機(jī)的某一種型號又可提供多種封裝工藝的產(chǎn)品：帶窗口的

20、EPROM型芯片，適合程序反復(fù)修改的開發(fā)階段；一次編程（OTP）的EPROM芯片，適合于小批量試生產(chǎn)和快速上市的需要；ROM掩模型芯片，適合大企業(yè)大批量定型產(chǎn)品的規(guī)模化生產(chǎn)；個別型號具有EEPROM或Flash程序存儲器，特別適合初學(xué)者"在線"反復(fù)擦寫、練習(xí)編程。</p><p>　　（16）程序保密性強(qiáng)。目前尚無辦法對PIC系列單片機(jī)的程序直接進(jìn)行解密拷貝，可以最大限度地保護(hù)用戶的程序版權(quán)。

21、</p><p>　　在PIC系列單片機(jī)中，PIC16F873是微芯片公司于1998年底推出的一款特色鮮明的新產(chǎn)品，它除了具有上述特點(diǎn)之外，還有一個最重要的特點(diǎn)，就是它可以實(shí)現(xiàn)在線調(diào)試和在線編程。這是MCS－51 和MC68系列單片機(jī)所不具備的，但卻正是廣大單片機(jī)初學(xué)者最需要的。</p><p>　　微芯片公司還專為此款單片機(jī)開發(fā)了一套小巧廉價的仿真工具套件，以下簡稱"仿真板&q

22、uot;或MPLAB－ICD。在該仿真板上既可以實(shí)現(xiàn)硬件仿真，又可以實(shí)現(xiàn)程序燒錄，還保留了一塊用戶可以隨意焊接一些元器件的布滿焊孔的電路板空間。由此可見，開發(fā)PIC16F873比前面介紹的開發(fā)其它PIC型號單片機(jī)的手段就更加簡便易行。當(dāng)然，如果只是為了學(xué)習(xí)，也可以一分錢不花，只用免費(fèi)的軟件綜合開發(fā)環(huán)境（MPLAB－IDE），對PIC16F873進(jìn)行軟件模擬仿真來調(diào)試程序。該軟件約有24M字節(jié)，并可以從因特網(wǎng)上下載，該公司還在中國開設(shè)了中

23、文網(wǎng)站，其網(wǎng)址為：http://www.microchip.com.cn/。</p><p>　　其實(shí)在PIC單片機(jī)的家族中，PIC16F873還有另外三個"近親弟兄"，它們分別是PIC16F874、PIC16F876、PIC16F877。微芯片公司將這四兄弟統(tǒng)稱為PIC16F87×。它們之間的差別很小，學(xué)會其中一款就基本上等于認(rèn)識了這四兄弟，所以我們先在其中挑一款相對簡單的型號向大

24、家介紹?？傮w上講，論本領(lǐng)、威力或者性能的話，在眾多的PIC單片機(jī)家族成員中，PIC16F87×占據(jù)著中上等水平。有的初學(xué)者可能要問，既然PIC系列中還有更簡單易學(xué)的品種，為什么先給大家引見PIC16F873呢？理由就是該型號具備讓人接近的良好途徑--在線調(diào)試和在線編程。借助于這項(xiàng)獨(dú)特的性能，我們可以邊學(xué)邊練，學(xué)用結(jié)合。</p><p>　　PIC series monolithic integrated

25、 circuit characteristic</p><p>　　Along with the large scale integrated circuit (LSI) the manufacture technology rapid development, the computer is facing two obvious directions (namely two big branches) to d

26、evelop: One is the microcomputer system performance enhances unceasingly, by satisfies the high velocity large capacity data processing; Two is the monolithic microcomputer function consummates day by day, by satisfies m

27、any domains each kind of intriguing scene control.</p><p>　　The Texas instrument company invented after 1975 in the world the first 4 monolithic integrated circuit TMS - 1,000 births, some large-scale micro

28、electron companies competed to develop have developed each kind of monolithic integrated circuit series product. Divides from the word length aspect, the monolithic integrated circuit has 4, 8, 16, 32 four big kinds, fir

29、st three kinds occupied the monolithic integrated circuit market main share, in the middle of these three kind of monolithic integrat</p><p>　　Has the representative 4 monolithic integrated circuits to have

30、the American Texas instrument company TMS - 1,000, Nippon Electric Company (NEC) mu PD75 long neck hair series, American country semiconductor company (NS) COP400 series, American company (ROCKWELL) PPS/1 series, Japanes

31、e Panasonic company's MN1400 series, Japanese Fujitsu Corporation's MB88 series as well as Japanese Sharp Corporation's SM long neck hair series and so on.</p><p>　　Has the representative 8 monol

32、ithic integrated circuits to have the American micro chip company the PIC16C long neck hair series, the PIC17C long neck hair series, the PIC1400 series, American Intel Corporation's MCS - 48 and the MCS - 51 series,

33、 the American Motorola Corporation's MC68HC05 series and the MC68HC11 series, the American uneven speech company's Z8 series, the Nippon Electric Company mu the PD78 long neck hair series, American Moses the Turk

34、 company and young attendants to the immor</p><p>　　At present, the monolithic integrated circuit is facing internal memory RAM and the ROM capacity is big, I/The O port function many, the supply voltage sco

35、pe width, the power dissipation are low, the operating speed quick direction develops.</p><p>　　In the above each kind of monolithic integrated circuit, why does this course select the micro chip company PIC

36、 in the series PIC16F873 monolithic integrated circuit to take the model introduction?</p><p>　　The PIC series monolithic integrated circuit hardware system design is succinct, command system design fining.

37、In the middle of all monolithic integrated circuits variety, it is easiest to study, one of easiest application monolithic integrated circuit varieties. Said regarding the monolithic integrated circuit beginner, if choos

38、es the PIC monolithic integrated circuit achievement to capture the monolithic integrated circuit kingdom the breach , will be a most relaxed shortcut, decides can obt</p><p>　　(2) And has used the differe

39、nt width, therefore program memory ROM and the data-carrier storage RAM addressing space is mutually independent, moreover two kind of memories widths are also different. Like this designs not only may guarantee the data

40、 the security, but also can enhance the running rate and realize the complete instruction the single byte. Byte said which in this, refers in particular to the PIC monolithic integrated circuit the instruction byte, but

41、is not 8 bits bytes which often </p><p>　　(3) Simplifies the set of instructions (RISC) the technology. PIC series monolithic integrated circuit command system only then 35 instructions. This for the instruc

42、tion study, the memory, the understanding brings the very big advantage, also gives the procedure the compilation, reading, the debugging, the revision, the exchange brings the enormous convenience, really it may be said

43、 is easy to study easily to use. But the MCS - 51 monolithic integrated circuits command systems altogether have 11</p><p>　　(4) The addressing way is simple. The addressing way is seeks the operand the meth

44、od. The PIC series monolithic integrated circuit only then 4 addressing ways (namely register indirect addressing, immediately number addressing, direct addressing and position addressing, later will make detailed explan

45、ation), will be easy to grasp, but MCS - 51 monolithic integrated circuits then will have 7 addressing ways, the 68HC05 monolithic integrated circuit will have 6 kinds.</p><p>　　(5)The code compression ratio

46、 is high. The 1K byte memory space, regarding likes the MCS - 51 such monolithic integrated circuits, only can deposit 600 instructions approximately, but regarding PIC series monolithic integrated circuit then can depos

47、it reaches 1,024 instructions strip number. May see from chart 1, compares with several kinds of typical monolithic integrated circuits, PIC16C5 is one kind most saves the program memory space the monolithic integrated c

48、ircuit. In other words, complet</p><p>　　(6) The running rate is high. Because has used the Harvard main line structure, also because instruction reading has selected the streamlined production method with t

49、he execution, the PIC series monolithic integrated circuit running rate enhances greatly. May see from chart 2, the PIC series monolithic integrated circuit running rate is higher than other same scales by far the monoli

50、thic integrated circuit. In all 8 machine center, PIC17C is in the present world one of speed quickest varieties.</p><p>　　(7) The power loss is low. The PIC series monolithic integrated circuit power dissip

51、ation is extremely low, some models monolithic integrated circuit works when the 4MHz clock consumes the electricity not to surpass 2mA, lowers under the sleep pattern to 1 mu A below.</p><p>　　(8) Driving f

52、orce. I/The O port actuates the load the ability to be strong, each I/The O pin inspiration and the output current maximum value may respectively achieve 25mA and 20mA, can the direct drive light emitter diode, the photo

53、electric coupler or the miniature relay and so on.</p><p>　　(9) Has I2C and the SPI serial main line port: PIC series monolithic integrated circuit some models has I2C and the SPI serial main line port. I2C

54、and SPI respectively are invents by PHILIPS and MOTOROLA Corporation realizes the synchronization serial data transmission SDT two kind of serial main lines technology between the chip. May facilitate using the monolithi

55、c integrated circuit serial main line port nimbly expands some essential periphery components. Serial interface and serial main line </p><p>　　(10) The addressing space design is succinct. The PIC series mon

56、olithic integrated circuit procedure, the storehouse, the data three use mutually the independent addressing respectively (or address code) the space, moreover the first two addresses arrangement does not need the user t

57、o worry, this can receive beginner's welcome. But MC68HC05 and MC68HC11 monolithic integrated circuit addressing space when, programming needs the user to the procedure area, the storehouse area, the data area and I/

58、</p><p>　　(11) The periphery electric circuit is succinct. The PIC series monolithic integrated circuit internal integrated on the electricity replacement electric circuit, I/On the O pin pulls the electric

59、circuit, the watch-dog timer and so on, may the greatest degree reduction or exempts with the periphery component, in order to realizes the pure monolithic application. Thus, not only is advantageous for the development,

60、 moreover also may save the user the electric circuit board space and the productio</p><p>　　(12) Develops conveniently. Usually, under the extra-curricular condition the study and the application monolithic

61、 integrated circuit, the biggest barrier is the experiment develops the equipment to be expensive, causes many beginners to shrink back at the sight. The micro chip company and its domestic many business agents have prov

62、ided the richly colorful hardware and the software support for user's application development. Has each kind of scale fever recording (or called programming) and the </p><p>　　(13) C language programming

63、. Regarding has grasped the C language user, the micro chip company has also provided the C language compiler for it , such user if uses the C language this kind of higher order language to carry on the programming, but

64、 also may enhance the working efficiency greatly.</p><p>　　(14) The variety is rich. The PIC series monolithic integrated circuit has formed three levels, more than 50 models at present. The internal functio

65、n from to is simply complex, the seal form from 8 feet to 68 feet, may meet each kind of different application need. The user always can find section in among to suit oneself develops the goal the monolithic integrated c

66、ircuit. In the seal form diversification aspect, does not like MCS - 51 series monolithic integrated circuits such, uses 40 feet sea</p><p>　　(15) The specification is complete. The micro chip company may pr

67、ovide the many kinds of seals craft to its monolithic integrated circuit some kind of model the product: The belt window EPROM chip, suits the phase of exploitation which the procedure revises repeatedly; A programming (

68、OTP) the EPROM chip, suits the need which and fast goes on the market in the trial production; ROM covers the model chip, suits the big enterprise mass stereotype product the production; The individual model has EEP</

69、p><p>　　(16) Procedure secret. At present still did not have the means to carry on the decipher copy directly to the PIC series monolithic integrated circuit procedure, might maximum limit protect the user the

70、procedure copyright.</p><p>　　In the PIC series monolithic integrated circuit, PIC16F873 is the micro chip company a section characteristic bright new product which promoted in 1998 year's end, it beside

71、s had the above characteristic, but also some most important characteristic, was it may realize the on-line debugging and the on-line programming. This is MCS - 51 and the MC68 series monolithic integrated circuit does n

72、ot have, but is precisely actually the general monolithic integrated circuits beginner most needs.</p><p>　　The micro chip company also specially developed set of exquisite inexpensive simulations tools set

73、of for this section monolithic integrated circuit, has hereafter referred to as the simulation board or MPLAB - ICD. Both may realize the hardware simulation on this simulation board, and may realize the procedure to bur

74、n the record, but also retained a user to be possible to weld some primary devices to cover entirely at will welds the hole the electric circuit board space. Thus it can be seen, de</p><p>　　In it really PIC

75、 monolithic integrated circuit family, PIC16F873 also has other three close relatives’ brother, they respectively are PIC16F874, PIC16F876, and PIC16F877. The micro chip company is called these four brothers is PIC16F87.

76、 Between them difference very small, academic society section on was basic superiorly in has known these four brothers, therefore we selected a section relatively simple model first in among to everybody introduction. In