DZ241電動汽車自動控制系統(tǒng),dz241,電動汽車,自動控制系統(tǒng) 微處理器1.1 前言微處理器是一個電子電路，其功能相當(dāng)于計算機(jī)的中央處理單元，提供計算的控制。微處理器也用于電子系統(tǒng)，例如計算機(jī)的打印機(jī)，汽車和噴氣飛機(jī)等，微處理器是一類超大規(guī)模集成電路。集成電路是復(fù)雜的電子電路，它由印制在單個，細(xì)小和平整的半導(dǎo)體材料上的極其微小的元件組成?，F(xiàn)代微處理器合并了多達(dá) 1 千萬個晶體管，另外還有像電阻，二極管，電容和導(dǎo)線等其他元件，通通裝進(jìn)大約郵票大小的一塊面積里。一個微處理器由幾個不同的部分組成，算術(shù)邏輯單元實(shí)現(xiàn)數(shù)字計算和邏輯推理判斷；寄存器是存儲器暫時信息的特殊記憶區(qū)，就像便攜本的功能一樣；控制單元解釋程序；總線承載出入芯片和計算機(jī)的數(shù)據(jù)信息；內(nèi)存支持片上計算。更復(fù)雜的微處理器往往包含其他部件，例如特殊存儲區(qū)，也叫高速緩存存儲器，也可以加速微處理器對外部數(shù)據(jù)存儲設(shè)備訪問。新式微處理器是以 64 比特的總線寬度工作的，這就是說，可同時傳輸 64 位數(shù)據(jù)，它是一個二進(jìn)制數(shù)，即用 1 和 0 表示的信息單位元。計算機(jī)的晶振提供協(xié)調(diào)微處理器所有活動的時鐘信號。最先進(jìn)的微處理器的時鐘頻率是 300MHz，允許在每秒鐘可以執(zhí)行 10 億個計算機(jī)指令。1.2 計算機(jī)存儲器由于微處理器本身不能提供大量的存儲空間去存儲程序指令和數(shù)據(jù)，像字處理程序中的文本，就需要晶體管與微處理器結(jié)合當(dāng)作存儲元件使用。單獨(dú)的存儲集成電路稱為隨機(jī)訪問存儲器，它包括大量的晶體管，與微處理器結(jié)合在一起提供需要的存儲空間。隨機(jī)訪問存儲器分為：靜態(tài) RAM 在有電時可以保存信息，由于其操作速度快，通常被當(dāng)作高速緩存存儲器使用。另一類存儲器是動態(tài) RAM 比靜態(tài)的速度慢，必須用電定期刷新，否則保持的信息將丟失。動態(tài) RAM 比靜態(tài) RAM 有更高的效率，在大多數(shù)計算機(jī)中，動態(tài) RAM 作為主要的存儲單元。1.3 微控制器微控制器不是完整的計算機(jī)。它沒有大容量的存儲器，也沒有能力鍵盤，游戲桿和鼠標(biāo)等輸入設(shè)備以及顯示器和打印器和打印機(jī)等輸出設(shè)備進(jìn)行通信。微控制器是一個不同類型的集成電路，它是一個完整的片上計算機(jī)面包喊了具有特殊功能的基本微處理器的所有功能部件。視頻游戲，錄象機(jī)，汽車和其他機(jī)器都使用了微控制器。1.4 半導(dǎo)體 所有的集成電路都是由半導(dǎo)體制造的，半導(dǎo)體的導(dǎo)電性能介于導(dǎo)體和非導(dǎo)體或絕緣體之間。硅是最通用的半導(dǎo)體材料。因?yàn)榘雽?dǎo)體的導(dǎo)電性能可以隨著施加電壓的改變而改變。由半導(dǎo)體制成的集體觀可以像微開關(guān)那樣動作，在僅僅幾納秒的時間內(nèi)可以切斷和連接電流。晶體管的這種能力可以使計算機(jī)一秒鐘執(zhí)行上百萬條單指令，也可以很快完成復(fù)雜的任務(wù)。大多數(shù)半導(dǎo)體器件的基本組成有二極管，N 型和 P 型的連接或合并。 “N”型和“P”型指的是經(jīng)過摻雜的半導(dǎo)體材料，控制加入非常少量的硼或磷這樣的雜質(zhì)。這些半導(dǎo)體材料的連接處，而且僅發(fā)生在 P 區(qū)電壓比 N 區(qū)高的情況下。這種情況下施加給二極管的電壓叫正向偏置。施加相反的電壓叫反向偏置，二極管沒有電流通過。一個集成電路包含有幾百萬個 PN 結(jié)，而且每一個結(jié)服務(wù)與特定的目的。P 區(qū)和 N 區(qū)的恰當(dāng)布局和偏置要求電流有正確的路徑，確保整個芯片正確地工作。1.5 晶體管在微電子行業(yè)廣泛使用的晶體管被稱為金屬氧化物半導(dǎo)體場效應(yīng)管。它包含有兩個 N 型區(qū)，被稱為源極和漏極，在源極和漏極之間的 P 型區(qū)被稱為溝道。在溝道上是一層很薄的不導(dǎo)電的二氧化硅，二氧化硅上面附的另一層叫做柵極。要使電流從源極流向漏極，必須在柵極加一個正偏壓。這就使得柵極像一個控制開關(guān)，連通和關(guān)斷 MOS 場效應(yīng)，構(gòu)成一個邏輯門，在微處理器中傳送數(shù)字 1 和 0。1.6 微處理器的制造制造微處理器采用的技術(shù)與制造其他集成電路使用的技術(shù)類似，例如存儲器芯片。微處理器通常具有比其他芯片更復(fù)雜的結(jié)構(gòu)，而且微處理器的制造需要極其精細(xì)的技術(shù)。微處理器的經(jīng)濟(jì)制造需要批量生產(chǎn)。在硅晶片的表面，上百個的掩膜或電路模式被同時制造出來。微處理器是通過導(dǎo)電物質(zhì)，絕緣物質(zhì)和半導(dǎo)體物質(zhì)的無數(shù)次沉積和清除過程制造的，每次一薄層，直到幾百萬個分離的步驟后，才制成一個復(fù)雜的“三明治” ，它包含了微處理器的所有內(nèi)部連線和電路。僅在硅晶體的外表面的部分被用于電子電路。加工處理的步驟包括襯基的制備，氧化，光刻，蝕刻，注入和薄膜沉積。生產(chǎn)微處理器的第一步是制造超純的硅基體，然后將所有圓晶體形狀的硅切片磨成平滑的鏡面。幾乎沉積在晶體的每一層都必須精確地按晶體管和其他電子元件的形狀制備。通常這個處理過程叫做光刻，它類似于把晶片轉(zhuǎn)換為一張攝像圖片和投射一個電路圖片在晶片上。晶片邊面的叫防光劑或防腐蝕劑的涂層，當(dāng)曝露在光線下將發(fā)生變化，這樣使得它很容易溶解在規(guī)定的模板中。這些模板的尺寸只有 0.25 微米，因?yàn)樽疃痰目梢姽獾牟ㄩL是大約 0.5 微米，短波長的紫外線才可以用于模板微小細(xì)節(jié)的溶解。光刻后，對晶片進(jìn)行腐蝕，或者用化學(xué)藥品進(jìn)行濕腐蝕，或者放在一個特別的裝有等離子體腐蝕氣體的密室中，出去抗蝕劑。緊接著的步驟是離子注入，像硼和磷等雜質(zhì)被摻入硅內(nèi)，可以改變其導(dǎo)電性。完成這個過程需要電離硼或者磷原子，用離子注入機(jī)使用巨大的能量將它們推進(jìn)晶片里，最后離子依次嵌入在晶片的表面中。用于構(gòu)建微處理器的薄層被稱做薄膜。這一過程的最后一步，是在一個等離子體濺射器中進(jìn)行沉積的，生成一層薄膜。這可以用蒸發(fā)法，把涂料熔化，然后蒸發(fā)，使其涂覆在晶片中；也可以用化學(xué)氣化沉積法，使涂料在低壓或正常氣壓下，從氣態(tài)濃縮在晶片中。在每種方法中，薄膜必須似是高度純凈的，它的厚度必須控制在幾個微米之內(nèi)。微處理器的結(jié)構(gòu)如此小和精細(xì)以至于灰塵可以破壞整個掩模。因?yàn)樯a(chǎn)微處理器車間的空氣需要極好的過濾和沒有任何灰塵，所以此車間被稱為清潔車間。今天最清潔的車間被定義為一類車間：它表明每立方英尺的空氣中超過 0.12μm 微粒的最大數(shù)目。1.7 微處理器的歷史第一個微處理器是 1971 年生產(chǎn)的英特爾 4004。它最初是為計算機(jī)開發(fā)的，但它是那個時代的革命，在這個 4 位微處理器上包含 2300 個晶體管，每秒鐘可以執(zhí)行將近 6 萬個指令。第一個 8 位微處理器是 1972 年開發(fā)的作為計算機(jī)終端的英特爾8080，它包含 4500 個晶體管，每秒能夠執(zhí)行 20 萬個指令?，F(xiàn)代微處理器具有更大的容量和更高的速度。1.8 未來技術(shù)微處理器和集成電路的制造技術(shù)變革非?？臁．?dāng)前，最復(fù)雜的微處理器集成了將近 1000 萬個晶體管。到 2000 年，先進(jìn)的微處理器將期望達(dá)到可以集成 5000 萬個晶體管，到 2010 年，將達(dá)到 80 億個。光刻技術(shù)也將改進(jìn)。到 2000 年，最小元件的尺寸將小于 0.2μm。按這樣的尺寸，即使最短的紫外線也可能達(dá)不到必須的精度?？赡艿倪x擇包括使用非常窄的電子和離子束，或者使用超短波長的 X 射線代替光刻技術(shù)。未來的微處理器可能需要像分子束外延和掃描隧道顯微檢查這些技術(shù)作為其制造工具。分子束外延是半導(dǎo)體在超真空的密室里一次一個原子地培植，利用掃描隧道顯微檢查，都能夠看到單個的原子，甚至以原子大小的精度對原子進(jìn)行移動。 Microprocessor1.IntroductionMicroprocessor is an electronic circuit that functions as the central processing unit (CPU) of a computer , providing computational control .Microprocessors are also used in other advanced electronic systems ,such as computer printers ,automobiles ,and jet airline .In 1995 about 4 billion microprocessors were produced worldwide .The microprocessor is one type of ultra-large-scale integrated circuit .Integrated circuits ,also known as microchips or chips ,are complex electronic circuits consisting of extremely tiny components formed on a single ,thin ,flat piece of material known as a semiconductor .Modern microprocessors incorporate as many as ten million transistors(which act as electronic amplifiers ,oscillators ,or ,most commonly, switches),in addition to other components such as resistors ,diodes ,capacitors ,and wires ,all packed into an area about the size of a postage stamp .A microprocessor consists of several different sections :the arithmetic/logic unit (ALU) performs calculations on numbers and makes logical decisions ;the registers are special memory locations for storing temporary information much as scratch pad does ;the control unit deciphers programs ;bused carry digital information throughout the chip and computer ;and local memory supports on-chip computation .More complex microprocessors often contain other sections ,such as sections of specialized memory ,called cache memory ,to speed up access to external data-storage devices .Modern microprocessors operate with bus widths of 64 bits ( binary digits ,or units of information represented as 1s and 0s ) ,meaning that 64 bits of data can be transferred at the same time .A crystal oscillator in the computer provides a clock signal to coordinate all activities of the microprocessor .The clock speed of the most advanced microprocessors is about 300 megahertz (MHz) –about 300 million cycles per second-allowing about a billion computer instructions to be executed every second . 2 .Computer Memory Because the microprocessor alone cannot accommodate the large amount of memory required to store program instructions and data ,such as the text in a word-processing program ,transistors can be used as memory elements in combination with the microprocessor .Separate integrated circuits ,called random-access memory (RAM) chips ,which contain large numbers of transistors ,are used in conjunction with the microprocessor to provide the needed memory .There are different kinds of random-access memory ,Static RAM (SRAM) holds information as long as power is turned on and is usually used as cache memory because it operates very quickly .Another type of memory ,dynamic RAM (DRAM) ,is slower than SRAM and must be periodically refreshed with electricity or the information it holds is lost .DRAM is more economical than SRAM and serves as the main memory element in most computers 3 .MicrocontrollerA microprocessor is not a complete computer .It does not contain large amounts of memory or have the ability to communicate with input devices ,such as keyboards ,joysticks ,and mice-or with output devices ,such as monitors and printers .A different kind of integrated circuit ,a microcontroller , is a complete computer on a chip ,containing all of the elements of the basic microprocessor along with other specialized functions .Microcontrollers are used in video games ,videocassette recorders (VCRs) automobiles ,and other machines . 4.SemiconductorsAll integrated circuits are fabricated from semiconductors ,substances whose ability to conduct electricity ranks between that of a conductor and that of a nonconductor ,or insulator .Silicon is the most common semiconductor material .Because the electrical conductivity of a semiconductor can change according to the voltage applied to it ,transistors made from semiconductors act like tiny switches that turn electrical concurrent on and off in just a few nanoseconds ( billionths of a second ) .This capability enables a computer to perform many millions of simple instructions each second and to complete complex tasks quickly . The basic building block of most semiconductor devices is the diode ,a junction ,or union ,of negative-type (n-type) and positive-type (p-type) materials .The terms n-type and p-type refer to conducting materials that have been doped-that is ,that have had their electrical properties altered by the controlled addition of very small quantities of impurities such as boron or phosphorus .In a diode ,current floes in only one direction :across the junction from the n-type material ,and then only when the p-type material is at a higher voltage than the n-type .The voltage applied to the diode to create this condition is called the forward bias ,the opposite voltage ,for which current will not flow ,is called the reverse bias ,An integrated circuit contains millions of p-n junctions ,each serving a specific purpose within the millions of electronic circuit elements .Proper placement and biasing of p- and n-type regions restrict the electrical current to the correct paths and ensure the operation of the entire chip .5.Transistors The transistor used most commonly in the microelectronics industry is called a metal-oxide-semiconductor field effect transistor (MOSFET) .it contains two n-type regions ,called the source and the drain ,with a p-type region in between them , called the channel .Over the channel is a thin layer of nonconductive silicon dioxide topped by another layer ,called the gate .For electrons to flow from the source to the drain ,a voltage (forward bias) must be applied to the gate .This cause the gate to act like a control switch ,turning the MOSFET on and creating a logic gate that transmits digital 1s and 0s throughout the microprocessor .6.Construction of Microprocessors Microprocessors are fabricated using techniques similar to those used for other integrated circuits ,such as memory chips .Microprocessor generally have a more complex structure than do other chips ,and their manufacture requires extremely precise techniques .Economical manufacturing of microprocessors requires mass production .Several hundred dies ,or circuit patterns ,are created on the surface of a silicon wafer simultaneously .Microprocessors are constructed by a process of deposition and removal of conducting ,insulating ,and conducting material one thin layer at a time until ,after hundreds of separate steps ,a complex sandwich is constructed that contains all the interconnected circuitry of the microprocessor . only the outer surface of the silicon wafer-a layer about 10 microns (about 0.01mm/0.0004in ) thick ( about one-tenth the thickness of a human hair )—is used for the electronic circuit .The processing steps include substrate creation ,oxidation ,lithography ,etching ,ion implantation ,and film deposition .The first step in producing a microprocessor is the creation of an ultra pure silicon substrate ,a silicon slice in the shape of a round wafer that is polished to a mirror like smoothness .At present ,the largest wafers used in industry are 200 mm (8 in) in diameter .In the oxidation step , an electrically no conducting layer ,called a dielectric ,is placed between each conductive layer on the wafer . The most important type of dielectric is silicon dioxide ,which is ‘grown’ by exposing the silicon wafer to oxygen in a furnace at about 1000 . The oxygen combines with the silicon to form a thin layer of oxide about 75 angstroms deep ( an angstrom is one ten-billionth of a meter ) .Nearly every layer that is deposited on the wafer must be patterned accurately into the shape of the transistors and other electronic elements .Usually this is done in process known as photolithography ,which is analogous to transforming the wafer into a piece of photographic film and projecting a picture of the circuit on it . A coating on the surface of the wafer ,called the resist ,changes when exposed to light ,making it east to dissolve in a developing solution .These patterns are as small as 0.25 microns in size .because th shortest wavelength of visible light is about 005 microns ,Short-wave-length ultraviolet light must be used to resolve the tiny details of the patterns .After photolithography ,the wafer is etched-that is ,the resist is removed from the wafer either by chemicals ,in a process known as wet etching ,or by exposure to a corrosive gas , called a plasma , in a special vacuum chamber .In the next step of the process ,ion implantation ,impurities such as boron and phosphorus are introduced into the silicon to alter its conductivity .This is accomplished by ionizing the boron or phosphorus atoms ( stripping off one or two electrons ) and propelling them at the wafer with an ion implanter at very high energies . The ions become embedded in the surface of the wafer .The thin layers used to build up a microprocessor are referred to as films .In the final step of the process ,the films are deposited using sputters in which thin films are grown in a plasma ;by means of evaporation whereby the material is melted and then evaporated coating the wafer ;or by means of chemical-vapor deposition ,whereby the material condenses from a gas at low or atmospheric pressure .In each case ,the film must be of high purity and its thickness must be controlled within a small fraction of a micron . Microprocessor features are to small and precise that a single speck of dust can destroy an entire die .The rooms used for microprocessor creation are called clean rooms because the air in them is extremely well filtered and virtually free of dust .The purest of today’s clean rooms are referred to as class 1 , indicating the maximum number of allowed particles larger than 0.12 micron in one cubic foot of air .( For comparison , a typical home is class one million or so ).History of the MicroprocessorThe first microprocessor was the Intel 4004 ,produced in 1971 Originally developed for a calculator ,and revolutionary for its time ,it contained 2,300 transistors on a 4-bit microprocessor that could perform only 60,000 operations per second .The first 8-bit microprocessor was the Intel8008 ,developed in 1972 to run computer terminals ,The Intel 8008 contains 3,300transistors .The first truly general-purpose microprocessor ,developed in 1974 , was the 8-bit Intel8080 ,which contained 4,500 transistors and could execute 200,000 instructions per second .Modern microprocessors have much greater capacity and speed .They include the Intel Pentium Pro ,containing 5.5 million transistors ;the UltraSparc-II ,by Sun Microsystems ,containing 5.4 million transistors ;the PowerPC620 , developed jointly by Apple ,IBM ,and Motorola , and containing 7 million transistors ;and the Digital Equipment Corporation’s Alpha 21164A ,containing 9.3 million transistors . 8.Future TechnologyThe technology of microprocessors and integrated-circuit fabrication is changing rapidly .Currently ,the most sophisticated microprocessors contain about 10 million transistors .By the year 2000 ,advanced microprocessors are expected to contain more than 50 million transistors ,and about 800 million by 2010.Lithographic techniques will also require improvements . By the year 2000 ,minimum element size will be less than 0.2 microns .At these dimensions ,even short-wave-length ultraviolet light may not reach the necessary resolution .Alternative possibilities include using very narrow beams of electrons and ions or replacing optical lithography with lithography that uses X rays of extremely short wavelength .U sing these technologies ,clock speeds could increase to more than 1,000 MHz by 2010 . It is expected that the limiting factor in microprocessor performance will be the behavior of the electrons themselves as they are propelled through the transistors .At extremely small dimensions ,quantum effect due to the wavelike nature of electrons could dominate the behavior of transistors and circuits .New devices and circuit designs may be necessary as microprocessors approach atomic dimensions .Techniques including molecular-beam epitaxy, in which semiconductors are layered one atom at a time in an ultra-high-vacuum chamber ,and scanning tunneling microscopy ,whereby single atoms can be viewed and even moved with atomic precision ,may be the tools needed to produce future generations of microprocessors .