外文翻譯--基于at89c52的led概述

1、<p>　　2000英文單詞，10900英文字符，4050漢字</p><p>　　Based on AT89C52 LED overview</p><p>　　LED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can be direct

2、ly converted into electricity to light. LED is the heart of a semiconductor chip, the chip is attached to one end of a stent, is the negative side, the other end of the power of the cathode, the entire chip package to be

3、 epoxy resin. Semiconductor chip is composed of two parts, part of the P-type semiconductor, it inside the hole-dominated, the other side is the N-type semiconductor, here</p><p>　　LED history 50 years ago,

4、 people have to understand semiconductor materials can produce light of the basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an elect

5、roluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the seismic per

6、formance LED good. </p><p>　　LED is the core of the P-type semiconductor and components of the N-type semiconductor chips, the P-type semiconductor and N-type semiconductor between a transition layer, call

7、ed the PN junction. In some semiconductor materials in the PN junction, the injection of a small number of carrier-carrier and the majority of the extra time will be in the form of light energy to release, thus the power

8、 to direct conversion of solar energy. PN junction on reverse voltage, a few hard-carrier injection, it </p><p>　　Instruments used for the first LED light source instructions, but all kinds of light colored

9、LED lights in traffic and large screen has been widely applied, have a very good economic and social benefits. The 12-inch red traffic lights as an example, is used in the United States have long life, low-efficiency 140

10、 watt incandescent lamp as a light source, it produced 2,000 lumens of white light. The red filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design, Lumi</p><p>　　For genera

11、l lighting, people need more white light sources. The 1998 white LED successful development. This is the GaN LED chip and Yttrium Aluminum Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd = 3

12、0nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the LED-based Wanxing reflection in the cavity, covered with

13、 a resin mixed with YAG thin layer, about 200-500 </p><p>　　In the 1960s, the use of science and technology workers semiconductor PN junction of The principle of developing a LED light-emitting diodes. At th

14、at time, the development of LED, the materials used are GaASP, its luminous color is red. After nearly 30 years of development, and now we are very familiar with the LED, has been sent to red, orange, yellow, green, blue

15、, and other shade. However lighting necessary for white LED light only in recent years to develop, readers here to tell us about ligh</p><p>　　The LED display screen and video display into the text by LED ma

16、trix blocks. Graphic display can be displayed with computer, English, Chinese text and graphics, Video screen using microcomputer control, graphic, image, with real-time, synchronization, clear information dissemination

17、way play all kinds of information, but also shows 2d, 3d animation, videos, TV, VCD programs and live. The LED display screen display bright colors, stereo sense is strong, such as oil, such as films, widely used in <

18、/p><p>　　The LED display can display the change of digital image; text, graphics, Not only can be used for indoor environment can also be used in outdoor environment, projectors, LCD TV wall, and the incomparab

19、le advantages.</p><p>　　LED by the wide attention and rapid development, and it is the advantages of itself. These advantages in is: high brightness, working voltage, low consumption, miniaturization, impact

20、 resistance and long service life and stable performance. LED the development prospect, is currently towards a higher brightness, higher resistance to climate, higher and higher light shine density evenness, reliability,

21、 the direction of development. Full-color</p><p>　　The classification of the LED display</p><p>　　1, the color can be divided into gezer</p><p>　　The single color display: single co

22、lors (red or green).</p><p>　　Double colors: red and green screen, double colors gray, can show 256 levels 65536 colors.</p><p>　　Full-color display: red, green, and blue, gray level 256 gezer f

23、ull-color display screen can show more than 1,600 colors.</p><p>　　2, according to the classification of display devices</p><p>　　LED digital display: display device for seven yards, suitable fo

24、r making the clock display screen, interest rates, digital electronic display screen.</p><p>　　Pictures of LED dot matrix LCD display device is composed of many: evenly composed of light emitting diode matri

25、x display module, suitable for broadcast text, images of information.</p><p>　　LED video display: display device is composed by many light-emitting diodes, video, animation shows various video files.</p&g

26、t;<p>　　3, by using occasions classification</p><p>　　Indoor display: light point is lesser, general Φ 3mm - Φ 8mm, display area of general several ten square meters to.</p><p>　　Outdoor

27、screen area to several hundred square meters general dozens, high brightness, can work under the sun, in the wind, rain, waterproof function.</p><p>　　4 points, according to the classification of light in di

28、ameter</p><p>　　Indoor screens: Φ 3mm, Φ 3.75 mm, Φ 5mm,</p><p>　　Outdoor screen: Φ 10mm, Φ 12mm and Φ 16mm Φ, 19mm, Φ 20mm, Φ 21mm, Φ 22mm, Φ 26mm</p><p>　　The basic unit of the li

29、ght outdoor screen for led light cone tube, the principle is a group of red, green, and blue light emitting diode sealed in a plastic tube in common</p><p>　　5. Display horizontally scrolling, static, vertic

30、al scroll and flip shows, etc. Single block module control drive 12 (maximum control and block), 16X48 matrix 8X8 matrix (or 32X48 matrix), is a single block of MAX7219 (or PS7219, HD7279, ZLG7289 8279 and other similar

31、LED display driver module) 12 times (or 24 times)! Can use "cascade" means any bitmap big screen composed. Show good effect, low consumption, and the cost of using MAX7219 circuit is lower.</p><p>

32、　　The LED display inspection method,</p><p>　　See appearance, specifications, screen body flatness, screen the attachment within2 look bad, after the light screen is not in scope, the screen (generally now b

33、asically no)</p><p>　　Color consistency, displays text display is normal, the picture to screen, full-color play white, red, green and blue.</p><p>　　Technical advantage</p><p>　　Ex

34、isting common indoor full-color scheme comparison:</p><p>　　1 the matrix modules: design, color dot matrix LCD by indoor artifacts</p><p>　　Advantage: the cost of raw materials, production and p

35、rocessing of the most advantage of simple process, quality is stable.</p><p>　　Faults: color consistency, Mosaic phenomenon, serious effect.</p><p>　　2. Single lamp schemes for solving the bitma

36、p screen color: for outdoor screen technology, a scheme of pixels, outdoor multiplexing technique (also called pixel sharing technology, virtual pixels to indoor display technology) transplantation.</p><p>　

37、　Advantage: color consistency than bitmap module of good way.</p><p>　　Weakness: the effect not beautiful, color mixing, horizontal Angle and have off color. Process is relatively complex, anti-static high.

38、Actual pixel resolution do 10,000 more difficult.</p><p><b>　　Features</b></p><p>　　? Compatible with MCS-51® Products</p><p>　　? 8K Bytes of In-System Programmable

39、 (ISP) Flash Memory</p><p>　　? 1000 Write/Erase Cycles</p><p>　　? Fully Static Operation: 0 Hz to 33 MHz</p><p>　　? Three-level Program Memory Lock</p><p>　　? 256 x 8-b

40、it Internal RAM</p><p>　　? 32 Programmable I/O Lines</p><p>　　? Three 16-bit Timer/Counters</p><p>　　? Eight Interrupt Sources</p><p>　　? Full Duplex UART Serial Channe

41、l</p><p>　　? Low-power Idle and Power-down Modes</p><p>　　? Interrupt Recovery from Power-down Mode</p><p>　　? Watchdog Timer</p><p>　　? Dual Data Pointer</p>&

42、lt;p>　　? Power-off Flag</p><p>　　Description</p><p>　　The AT89C52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. The device

43、is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and pinout. The on-chip Flash allows the programmemory to be reprogrammed in-sys

44、tem or by a conventional nonvolatile memory programmer.By combining a versatile 8-bit CPU with in system programmable Flash on a monolithicchip</p><p>　　In the Counter function, the register is incremented i

45、n response to a 1-to-0 transition at its corresponding external input pin, T2. In this function, the external input is sampled during S5P2 of every machine cycle. When the samples show a high in one cycle and a low in th

46、e next cycle, the count is incremented. The new count value appears in the register during S3P1 of the cycle following the one in which the transition was detected. Since two machine cycles (24 oscillator periods) are re

47、quired</p><p>　　Interrupts</p><p>　　The AT89C52 has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial port in

48、terrupt. These interrupts are all shown in Figure 10. Each of these interrupt sources can be individually enabled or disabled by setting or clearing a bit in Special Function Register IE. IE also contains a global disabl

49、e bit, EA, which</p><p>　　disables all interrupts at once. Note that Table 5 shows that bit position IE.6 is unimplemented. In the AT89C52, bit position IE.5 is also unimplemented.</p><p>　　User

50、 software should not write 1s to these bit positions, since they may be used in future AT89 products. Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in register T2CON. Neither of these flags is cle

51、ared by hardware when the service routine is vectored to. In fact, the service routine may have to determine whether it was TF2 or EXF2 that generated the interrupt, and that bit will have to be cleared in software. The

52、Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 </p><p>　　基于AT89C52的LED概述</p><p>　　LED（Light Emitting Diode），發(fā)光二極管，是一種固態(tài)的半導(dǎo)體器件，它可以直接把電轉(zhuǎn)化為光。LED的心臟是一個(gè)半導(dǎo)體的晶片，晶片的一端附在一個(gè)支架上，一端是負(fù)極，另一端連接電源的正極，使

53、整個(gè)晶片被環(huán)氧樹(shù)脂封裝起來(lái)。半導(dǎo)體晶片由兩部分組成，一部分是P型半導(dǎo)體，在它里面空穴占主導(dǎo)地位，另一端是N型半導(dǎo)體，在這邊主要是電子。但這兩種半導(dǎo)體連接起來(lái)的時(shí)候，它們之間就形成一個(gè)“P-N結(jié)”。當(dāng)電流通過(guò)導(dǎo)線(xiàn)作用于這個(gè)晶片的時(shí)候，電子就會(huì)被推向P區(qū)，在P區(qū)里電子跟空穴復(fù)合，然后就會(huì)以光子的形式發(fā)出能量，這就是LED發(fā)光的原理。而光的波長(zhǎng)也就是光的顏色，是由形成P-N結(jié)的材料決定的。</p><p>　　L

54、ED歷史50年前人們已經(jīng)了解半導(dǎo)體材料可產(chǎn)生光線(xiàn)的基本知識(shí)，第一個(gè)商用二極管產(chǎn)生于1960年。LED是英文light emitting diode（發(fā)光二極管）的縮寫(xiě)，它的基本結(jié)構(gòu)是一塊電致發(fā)光的半導(dǎo)體材料，置于一個(gè)有引線(xiàn)的架子上，然后四周用環(huán)氧樹(shù)脂密封，即固體封裝，所以能起到保護(hù)內(nèi)部芯線(xiàn)的作用，所以L(fǎng)ED的抗震性能好。發(fā)光二極管的核心部分是由P型半導(dǎo)體和N型半導(dǎo)體組成的晶片，在P型半導(dǎo)體和N型半導(dǎo)體之間有一個(gè)過(guò)渡層，稱(chēng)為P-N結(jié)。在某

55、些半導(dǎo)體材料的PN結(jié)中，注入的少數(shù)載流子與多數(shù)載流子復(fù)合時(shí)會(huì)把多余的能量以光的形式釋放出來(lái)，從而把電能直接轉(zhuǎn)換為光能。PN結(jié)施加反向電壓時(shí)，少數(shù)載流子難以注入，故不發(fā)光。這種利用注入式電致發(fā)光原理制作的二極管叫發(fā)光二極管，通稱(chēng)LED。 當(dāng)它處于正向工作狀態(tài)時(shí)（即兩端加上正向電壓），電流從LED陽(yáng)極流向陰極時(shí)，半導(dǎo)體晶體就發(fā)出從紫外到紅外不同顏色的光線(xiàn)，光的強(qiáng)弱與電流有關(guān)。 </p><p>　　最初LED用作

56、儀器儀表的指示光源，后來(lái)各種光色的LED在交通信號(hào)燈和大面積顯示屏中得到了廣泛應(yīng)用，產(chǎn)生了很好的經(jīng)濟(jì)效益和社會(huì)效益。以12英寸的紅色交通信號(hào)燈為例，在美國(guó)本來(lái)是采用長(zhǎng)壽命、低光效的140瓦白熾燈作為光源，它產(chǎn)生2000流明的白光。經(jīng)紅色濾光片后，光損失90%，只剩下200流明的紅光。而在新設(shè)計(jì)的燈中，Lumileds公司采用了18個(gè)紅色LED光源，包括電路損失在內(nèi)，共耗電14瓦，即可產(chǎn)生同樣的光效。 汽車(chē)信號(hào)燈也是LED光源應(yīng)用的重要領(lǐng)

57、域。 </p><p>　　對(duì)于一般照明而言，人們更需要白色的光源。1998年白光的LED開(kāi)發(fā)成功。這種LED是將GaN芯片和釔鋁石榴石（YAG）封裝在一起做成。GaN芯片發(fā)藍(lán)光（λp=465nm，Wd=30nm），高溫?zé)Y(jié)制成的含Ce3+的YAG熒光粉受此藍(lán)光激發(fā)后發(fā)出黃色光射，峰值550nm。藍(lán)光LED基片安裝在碗形反射腔中，覆蓋以混有YAG的樹(shù)脂薄層，約200-500nm。 LED基片發(fā)出的藍(lán)光部分被熒

58、光粉吸收，另一部分藍(lán)光與熒光粉發(fā)出的黃光混合，可以得到得白光?，F(xiàn)在，對(duì)于InGaN/YAG白色LED，通過(guò)改變YAG熒光粉的化學(xué)組成和調(diào)節(jié)熒光粉層的厚度，可以獲得色溫3500-10000K的各色白光。這種通過(guò)藍(lán)光LED得到白光的方法，構(gòu)造簡(jiǎn)單、成本低廉、技術(shù)成熟度高，因此運(yùn)用最多。 </p><p>　　上個(gè)世紀(jì)60年代，科技工作者利用半導(dǎo)體PN結(jié)發(fā)光的原理，研制成了LED發(fā)光二極管。當(dāng)時(shí)研制的LED，所用的

59、材料是GaASP，其發(fā)光顏色為紅色。經(jīng)過(guò)近30年的發(fā)展，現(xiàn)在大家十分熟悉的LED，已能發(fā)出紅、橙、黃、綠、藍(lán)等多種色光。然而照明需用的白色光LED僅在近年才發(fā)展起來(lái)，這里向讀者介紹有關(guān)照明用白光。</p><p>　　LED顯示屏分為圖文顯示屏和視頻顯示屏，均由LED矩陣塊組成。圖文顯示屏可與計(jì)算機(jī)同步顯示漢字、英文文本和圖形；視頻顯示屏采用微型計(jì)算機(jī)進(jìn)行控制，圖文、圖像并茂，以實(shí)時(shí)、同步、清晰的信息傳播方式播放

60、各種信息，還可顯示二維、三維動(dòng)畫(huà)、錄像、電視、VCD節(jié)目以及現(xiàn)場(chǎng)實(shí)況。LED顯示屏顯示畫(huà)面色彩鮮艷，立體感強(qiáng)，靜如油畫(huà)，動(dòng)如電影，廣泛應(yīng)用于金融、稅務(wù)、工商、郵電、體育、廣告、廠礦企業(yè)、交通運(yùn)輸、教育系統(tǒng)、車(chē)站、碼頭、機(jī)場(chǎng)、商場(chǎng)、醫(yī)院、賓館、銀行、證券市場(chǎng)、建筑市場(chǎng)、拍賣(mài)行、工業(yè)企業(yè)管理和其它公共場(chǎng)所。 </p><p>　　LED顯示屏可以顯示變化的數(shù)字、文字、圖形圖像；不僅可以用于室內(nèi)環(huán)境還可以用于室外

61、環(huán)境，具有投影儀、電視墻、液晶顯示屏無(wú)法比擬的優(yōu)點(diǎn)。 </p><p>　　LED之所以受到廣泛重視而得到迅速發(fā)展，是與它本身所具有的優(yōu)點(diǎn)分不開(kāi)的。這些優(yōu)點(diǎn)概括起來(lái)是：亮度高、工作電壓低、功耗小、小型化、壽命長(zhǎng)、耐沖擊和性能穩(wěn)定。LED的發(fā)展前景極為廣闊，目前正朝著更高亮度、更高耐氣候性、更高的發(fā)光密度、更高的發(fā)光均勻性，可靠性、全色化方向發(fā)展。 </p><p>　　LED顯

62、示屏的分類(lèi)：1、按顏色基色可以分為 ，單基色顯示屏:單一顏色（紅色或綠色）。雙基色顯示屏：紅和綠雙基色，256級(jí)灰度、可以顯示65536種顏色。全彩色顯示屏：紅、綠、藍(lán)三基色，256級(jí)灰度的全彩色顯示屏可以顯示一千六百多萬(wàn)種顏色。2、按顯示器件分類(lèi)：LED數(shù)碼顯示屏：顯示器件為7段碼數(shù)碼管，適于制作時(shí)鐘屏、利率屏等，顯示數(shù)字的電子顯示屏。 </p><p>　　LED點(diǎn)陣圖文顯示屏：顯示器件是由許多均勻排列

63、的發(fā)光二極管組成的點(diǎn)陣顯示模塊，適于播放文字、圖像信息。 </p><p>　　LED視頻顯示屏：顯示器件是由許多發(fā)光二極管組成，可以顯示視頻、動(dòng)畫(huà)等各種視頻文件。3、按使用場(chǎng)合分類(lèi)，室內(nèi)顯示屏：發(fā)光點(diǎn)較小，一般Φ3mm--Φ8mm，顯示面積一般幾至十幾平方米。室外顯示屏：面積一般幾十平方米至幾百平方米，亮度高，可在陽(yáng)光下工作，具有防風(fēng)、防雨、防水功能。4、按發(fā)光點(diǎn)直徑分類(lèi)，室內(nèi)屏：Φ3mm、Φ3.75mm

64、、Φ5mm。室外屏：Φ10mm、Φ12mm、Φ16mm、Φ19mm、Φ20mm、Φ21mm、Φ22mm、Φ26mm 。室外屏發(fā)光的基本單元為發(fā)光筒，發(fā)光筒的原理是將一組紅、綠、藍(lán)發(fā)光二極管封在一個(gè)塑料筒內(nèi)共同發(fā)。5.顯示方式有靜態(tài)、橫向滾動(dòng)、垂直滾動(dòng)和翻頁(yè)顯示等。單塊模塊控制驅(qū)動(dòng)12塊（最多可控制24塊）8X8點(diǎn)陣，共16X48點(diǎn)陣（或32X48點(diǎn)陣），是單塊MAX7219（或PS7219、HD7279、ZLG7289及8279等類(lèi)似L

65、ED顯示驅(qū)動(dòng)模塊）的12倍（或24倍）！可采用“級(jí)聯(lián)”的方式組成任意點(diǎn)陣大顯示屏。顯示效果好，功耗小，且比采用MAX7219電路的成本更低。LED顯示屏檢驗(yàn)方法，一看屏體規(guī)格，外觀，平整度，屏內(nèi)的連線(xiàn)等。二看屏點(diǎn)亮后壞點(diǎn)，在不在不</p><p><b>　　主要性能</b></p><p>　　與MCS-51單片機(jī)產(chǎn)品兼容</p><p>　

66、　8K字節(jié)在系統(tǒng)可編程Flash存儲(chǔ)器</p><p><b>　　1000次擦寫(xiě)周期</b></p><p>　　全靜態(tài)操作：0Hz～33Hz</p><p><b>　　三級(jí)加密程序存儲(chǔ)器</b></p><p>　　32個(gè)可編程I/O口線(xiàn)</p><p>　　三個(gè)16位

67、定時(shí)器/計(jì)數(shù)器</p><p><b>　　八個(gè)中斷源</b></p><p>　　全雙工UART串行通道</p><p>　　低功耗空閑和掉電模式</p><p><b>　　掉電后中斷可喚醒</b></p><p><b>　　看門(mén)狗定時(shí)器</b>&

68、lt;/p><p><b>　　雙數(shù)據(jù)指針</b></p><p><b>　　掉電標(biāo)識(shí)符</b></p><p><b>　　功能特性描述</b></p><p>　　AT89C52是一種低功耗、高性能CMOS8位微控制器，具有8K在系統(tǒng)可編程Flash 存儲(chǔ)器。使用Atmel公

69、司高密度非易失性存儲(chǔ)器技術(shù)制造，與工業(yè)80C51產(chǎn)品指令和引腳完全兼容。片上Flash允許程序存儲(chǔ)器在系統(tǒng)可編程，亦適于常規(guī)編程器。在單芯片上，擁有靈巧的8位CPU和在系統(tǒng)可編程Flash，使得AT89C52為眾多嵌入式控制應(yīng)用系統(tǒng)提供高靈活、超有效的解決方案。AT89C52具有以下標(biāo)準(zhǔn)功能：8k字節(jié)Flash，256字節(jié)RAM，32位I/O口線(xiàn)，看門(mén)狗定時(shí)器，2個(gè)數(shù)據(jù)指針，三個(gè)16位定時(shí)器/計(jì)數(shù)器，一個(gè)6向量2級(jí)中斷結(jié)構(gòu)，全雙工串行口

70、，片內(nèi)晶振及時(shí)鐘電路。另外，AT89C52可降至0Hz靜態(tài)邏輯操作，支持2種軟件可選擇節(jié)電模式?？臻e模式下，CPU停止工作，允許RAM、定時(shí)器/計(jì)數(shù)器、串口、中斷繼續(xù)工作。掉電保護(hù)方式下，RAM內(nèi)容被保存，振蕩器被凍結(jié)，單片機(jī)一切工作停止，直到下一個(gè)中斷或硬件復(fù)位為止。</p><p>　　ST: 復(fù)位輸入。晶振工作時(shí)，RST腳持續(xù)2個(gè)機(jī)器周期高電平將使單片機(jī)復(fù)位?？撮T(mén)狗計(jì)時(shí)完成后，RST腳輸出96個(gè)晶振周期的高

71、電平。特殊寄存器AUXR(地址8EH)上的DISRTO位可以使此功能無(wú)效。DISRTO默認(rèn)狀態(tài)下，復(fù)位高電平有效。</p><p>　　ALE/：地址鎖存控制信號(hào)（ALE）是訪(fǎng)問(wèn)外部程序存儲(chǔ)器時(shí)，鎖存低8位地址的輸出脈沖。在flash編程時(shí)，此引腳（）也用作編程輸入脈沖。</p><p>　　在一般情況下，ALE 以晶振六分之一的固定頻率輸出脈沖，可用來(lái)作為外部定時(shí)器或時(shí)鐘使用。然而，特別

72、強(qiáng)調(diào)，在每次訪(fǎng)問(wèn)外部數(shù)據(jù)存儲(chǔ)器時(shí)，ALE脈沖將會(huì)跳過(guò)。</p><p>　　如果需要，通過(guò)將地址為8EH的SFR的第0位置“1”，ALE操作將無(wú)效。這一位置“1”，ALE 僅在執(zhí)行MOVX 或MOVC指令時(shí)有效。否則，ALE 將被微弱拉高。這個(gè)ALE 使能標(biāo)志位（地址為8EH的SFR的第0位）的設(shè)置對(duì)微控制器處于外部執(zhí)行模式下無(wú)效。</p><p>　　:外部程序存儲(chǔ)器選通信號(hào)（）是外部程

73、序存儲(chǔ)器選通信號(hào)。當(dāng) AT89S52從外部程序存儲(chǔ)器執(zhí)行外部代碼時(shí)，在每個(gè)機(jī)器周期被激活兩次，而在訪(fǎng)問(wèn)外部數(shù)據(jù)存儲(chǔ)器時(shí)，將不被激活。/VPP:訪(fǎng)問(wèn)外部程序存儲(chǔ)器控制信號(hào)。為使能從0000H 到FFFFH的外部程序存儲(chǔ)器讀取指令，必須接GND。為了執(zhí)行內(nèi)部程序指令，應(yīng)該接VCC。在flash編程期間，也接收12伏VPP電壓。XTAL1:振蕩器反相放大器和內(nèi)部時(shí)鐘發(fā)生電路的輸入端。XTAL2:振蕩器反相放大器的輸出端。</p>

74、<p>　　存儲(chǔ)器結(jié)構(gòu):MCS-51器件有單獨(dú)的程序存儲(chǔ)器和數(shù)據(jù)存儲(chǔ)器。外部程序存儲(chǔ)器和數(shù)據(jù)存儲(chǔ)器都可以64K尋址。</p><p>　　程序存儲(chǔ)器：如果引腳接地，程序讀取只從外部存儲(chǔ)器開(kāi)始。對(duì)于89C52，如果接VCC，程序讀寫(xiě)先從內(nèi)部存儲(chǔ)器（地址為0000H～1FFFH）開(kāi)始，接著從外部尋址，尋址地址為：2000H~FFFFH。</p><p>　　中斷 AT89C52有

75、6個(gè)中斷源：兩個(gè)外部中斷（和），三個(gè)定時(shí)中斷（定時(shí)器0、1、2）和一個(gè)串行中斷。這些中斷每個(gè)中斷源都可以通過(guò)置位或清除特殊寄存器IE中的相關(guān)中斷允許控制位分別使得中斷源有效或無(wú)效。IE還包括一個(gè)中斷允許總控制位EA，它能一次禁止所有中斷。IE.6位是不可用的。對(duì)于AT89C52，IE.5位也是不能用的。用戶(hù)軟件不應(yīng)給這些位寫(xiě)1。它們?yōu)锳T89系列新產(chǎn)品預(yù)留。</p><p>　　定時(shí)器2可以被寄存器T2CON中的

76、TF2和EXF2的或邏輯觸發(fā)。程序進(jìn)入中斷服務(wù)后，這些標(biāo)志位都可以由硬件清0。實(shí)際上，中斷服務(wù)程序必須判定是否是TF2 或EXF2激活中斷，標(biāo)志位也必須由軟件清0。</p><p>　　定時(shí)器0和定時(shí)器1標(biāo)志位TF0 和TF1在計(jì)數(shù)溢出的那個(gè)周期的S5P2被置位。它們的值一直到下一個(gè)周期被電路捕捉下來(lái)。然而，定時(shí)器2的標(biāo)志位TF2在計(jì)數(shù)溢出的那個(gè)周期的S2P2被置位，在同一個(gè)周期被電路捕捉下來(lái)。</p>