單片機外文翻譯--修改版

1、<p>　　Electric boiler temperature system</p><p><b>　　1.MCU</b></p><p>　　A microcontroller (or MCU) is a computer-on-a-chip. It is a type of microprocessor emphasizing self-suffi

2、ciency and cost-effectiveness, in contrast to a general-purpose microprocessor (the kind used in a PC). </p><p>　　The majority of computer systems in use today are embedded in other machinery, such as teleph

3、ones, clocks, appliances, vehicles, and infrastructure. An embedded system usually has minimal requirements for memory and program length and may require simple but unusual input/output systems. For example, most embedde

4、d systems lack keyboards, screens, disks, printers, or other recognizable I/O devices of a personal computer. They may control electric motors, relays or voltages, and read switches, vari</p><p>　　In contras

5、t to general-purpose CPUs, microcontrollers do not have an address bus or a data bus, because they integrate all the RAM and non-volatile memory on the same chip as the CPU. Because they need fewer pins, the chip can be

6、placed in a much smaller, cheaper package. </p><p>　　Integrating the memory and other peripherals on a single chip and testing them as a unit increases the cost of that chip, but often results in decreased n

7、et cost of the embedded system as a whole. (Even if the cost of a CPU that has integrated peripherals is slightly more than the cost of a CPU + external peripherals, having fewer chips typically allows a smaller and chea

8、per circuit board, and reduces the labor required to assemble and test the circuit board). This trend leads to design. </p><p>　　A microcontroller is a single integrated circuit, commonly with the following

9、features: </p><p>　　central processing unit - ranging from small and simple 4-bit processors to sophisticated 32- or 64-bit processors input/output interfaces such as serial ports (UARTs) other serial commun

10、ications interfaces like I²C, Serial Peripheral Interface and Controller Area Network for system interconnect peripherals such as timers and watchdog RAM for data storage ROM, EPROM, EEPROM or Flash memory for pro

11、gram storage clock generator - often an oscillator for a quartz timing crystal, resonator or RC c</p><p>　　This integration drastically reduces the number of chips and the amount of wiring and PCB space tha

12、t would be needed to produce equivalent systems using separate chips and have proved to be highly popular in embedded systems since their introduction in the 1970s. </p><p>　　Some microcontrollers can afford

13、 to use a Harvard architecture: separate memory buses for instructions and data, allowing accesses to take place concurrently. </p><p>　　The decision of which peripheral to integrate is often difficult. The

14、Microcontroller vendors often trade operating frequencies and system design flexibility against time-to-market requirements from their customers and overall lower system cost. Manufacturers have to balance the need to mi

15、nimize the chip size against additional functionality. </p><p>　　Microcontroller architectures are available from many different vendors in so many varieties that each instruction set architecture could righ

16、tly belong to a category of their own. Chief among these are the 8051, Z80 and ARM derivatives.[citation needed] </p><p>　　A microcontroller (also MCU or µC) is a functional computer system-on-a-chip. I

17、t contains a processor core, memory, and programmable input/output peripherals.</p><p>　　Microcontrollers include an integrated CPU, memory (a small amount of RAM, program memory, or both) and peripherals ca

18、pable of input and output. </p><p>　　It emphasizes high integration, in contrast to a microprocessor which only contains a CPU (the kind used in a PC). In addition to the usual arithmetic and logic elements

19、of a general purpose microprocessor, the microcontroller integrates additional elements such as read-write memory for data storage, read-only memory for program storage, Flash memory for permanent data storage, periphera

20、ls, and input/output interfaces. At clock speeds of as little as 32KHz, microcontrollers often operate at very</p><p>　　Microcontrollers are used in automatically controlled products and devices, such as aut

21、omobile engine control systems, remote controls, office machines, appliances, power tools, and toys. By reducing the size, cost, and power consumption compared to a design using a separate microprocessor, memory, and inp

22、ut/output devices, microcontrollers make it economical to electronically control many more processes.</p><p>　　The majority of computer systems in use today are embedded in other machinery, such as automobil

23、es, telephones, appliances, and peripherals for computer systems. These are called embedded systems. While some embedded systems are very sophisticated, many have minimal requirements for memory and program length, with

24、no operating system, and low software complexity. Typical input and output devices include switches, relays, solenoids, LEDs, small or custom LCD displays, radio frequency devices, and</p><p>　　It is mandato

25、ry that microcontrollers provide real time response to events in the embedded system they are controlling. When certain events occur, an interrupt system can signal the processor to suspend processing the current instruc

26、tion sequence and to begin an interrupt service routine (ISR). The ISR will perform any processing required based on the source of the interrupt before returning to the original instruction sequence. Possible interrupt s

27、ources are device dependent, and often include </p><p>　　Microcontroller programs must fit in the available on-chip program memory, since it would be costly to provide a system with external, expandable, mem

28、ory. Compilers and assembly language are used to turn high-level language programs into a compact machine code for storage in the microcontroller's memory. Depending on the device, the program memory may be permanent

29、, read-only memory that can only be programmed at the factory, or program memory may be field-alterable flash or erasable read-only me</p><p>　　Since embedded processors are usually used to control devices,

30、they sometimes need to accept input from the device they are controlling. This is the purpose of the analog to digital converter. Since processors are built to interpret and process digital data, i.e. 1s and 0s, they won

31、't be able to do anything with the analog signals that may be being sent to it by a device. So the analog to digital converter is used to convert the incoming data into a form that the processor can recognize. There

32、i</p><p>　　In addition to the converters, many embedded microprocessors include a variety of timers as well. One of the most common types of timers is the Programmable Interval Timer, or PIT for short. A PIT

33、 just counts down from some value to zero. Once it reaches zero, it sends an interrupt to the processor indicating that it has finished counting. This is useful for devices such as thermostats, which periodically test th

34、e temperature around them to see if they need to turn the air conditioner on, the he</p><p>　　Time Processing Unit or TPU for short. Is essentially just another timer, but more sophisticated. In addition to

35、counting down, the TPU can detect input events, generate output events, and other useful operations.</p><p>　　Dedicated Pulse Width Modulation (PWM) block makes it possible for the CPU to control power conve

36、rters, resistive loads, motors, etc., without using lots of CPU resources in tight timer loops.</p><p>　　Universal Asynchronous Receiver/Transmitter (UART) block makes it possible to receive and transmit dat

37、a over a serial line with very little load on the CPU.</p><p>　　For those wanting ethernet one can use an external chip like Crystal Semiconductor CS8900A, Realtek RTL8019, or Microchip ENC 28J60. All of the

38、m allow easy interfacing with low pin count.</p><p><b>　　中文翻譯：</b></p><p><b>　　1.單片機</b></p><p>　　單片機即單片微型計算機，是把中央處理器、存儲器、定時/計數器、輸入輸出接口都集成在一塊集成電路芯片上的微型計算機。與應

39、用在個人電腦中的通用型微處理器相比，它更強調自供應（不用外接硬件）和節(jié)約成本。它的最大優(yōu)點是體積小，可放在儀表內部，但存儲量小，輸入輸出接口簡單，功能較低。由于其發(fā)展非常迅速，舊的單片機的定義已不能滿足，所以在很多應用場合被稱為范圍更廣的微控制器，但是目前在中國大陸仍多沿用“單片機”的稱呼。 </p><p>　　絕大多數現在的單片機都是基于馮·諾伊曼結構的，這種結構清楚地定義了嵌入式系統(tǒng)所必需的四個基

40、本部分：一個中央處理器核心，程序存儲器（只讀存儲器或者閃存）、數據存儲器（隨機存儲器），一個或者更多的定時/計時器，還有用來與外圍設備以及擴展資源進行通信的輸入/輸出端口——所有這些都被集成在單個集成電路芯片上。說單片機與通用型中央處理單元芯片不同是因為前者一般很容易配合最小型的外部支持芯片制成工作計算機。這樣就可以很容易的把單片機系統(tǒng)植入裝置內部來控制裝置了。近年來為了在指令和數據上使用不同的字寬，并提高處理器流水線速度，哈佛結構在微

41、控制器和DSP也逐漸得到了廣泛的應用。 </p><p>　　傳統(tǒng)的微處理器是不允許這么做的。它要完成單片機的工作，就必須連接一些其他芯片。比如說，片上沒有數據存儲器，就必須要添加一些RAM的存儲芯片，雖然所添加存儲器的容量很靈活，但是至少還是要添加，另外還需要添加很多連線來傳遞芯片之間的數據。 比如，一個典型的微控制器只需要一個時鐘發(fā)生器和很少的RAM和ROM(或者EPROM, E2PROM)就可以在軟件和晶振

42、下工作了。同時，微控制器具有豐富的輸入輸出設備，像是模擬數字轉換(ADC)，定時器，串口或者其他串行通訊接口(比如I2C，串行外圍接口(SPI),控制器局域網)。通常，這些繼承在內部的設備可以通過特殊的指令來操作。 一些現代的微控制器支持一些內建的高級編程語言，比如BASIC語言。一個微控制器（也叫MCU）是一個微型計算芯片。它包含一個處理器、一個內存（有少量的RAM ，程序存儲器，或兩者兼而有之）和一個可編程輸入/輸出外設。 <

43、/p><p>　　它強調高度集成，而相比之下，一個微處理器只包含一個CPU （比如一臺PC ） 。除了通常的算術和邏輯要素等一般用途的微處理器，微控制器還集成了更多的要素，如讀寫存儲器的數據存儲，只讀存儲器的存儲程序，快閃記憶體的永久數據存儲，外設，和輸入/輸出接口。在時鐘頻率只有32Mhz的情況下 ，微操作系統(tǒng)往往以非常低的速度相運行，但是這足夠典型的應用。他們消耗較少的功率（毫瓦或什微） ，且具有保持功能，同時可

44、以等待一個事件，如一個按鈕的按下或中斷。在睡眠狀態(tài)時， CPU時鐘和外設禁用，從而使它們適合用于低功耗和長期持久的電池應用。 </p><p>　　微控制器廣泛應用于自動控制產品和設備，如汽車發(fā)動機控制系統(tǒng)，遠程控制系統(tǒng)，辦公室機器設備系統(tǒng)，家用電器，電動工具，和玩具等。通過降低尺寸，成本和能耗，設計使用單獨的微處理器，內存和輸入/輸出設備，能夠使微控制器控制更多的進程，更經濟。</p><p

45、>　　目前，大多數的計算機系統(tǒng)被嵌入在其他設備中使用，如汽車，電話以及很多需要外設的計算機系統(tǒng)。這些嵌入其他設備的計算機系統(tǒng)被稱為嵌入式系統(tǒng)。有些嵌入式系統(tǒng)是非常復雜的，很多能夠達到人們的要求，但由于內存和程序長度的限制，軟件的復雜性降低。典型的輸入和輸出設備包括交換機，繼電器，螺線管，發(fā)光二極管，小形或定制的液晶顯示器，數碼顯示器等。射頻設備和傳感器等嵌入式系統(tǒng)通常沒有鍵盤，屏幕，硬盤，打印機或其他公認的I / O設備，并可能缺

46、乏人機互動裝置的任何一種。</p><p>　　某些強制性的微控制器能夠提供實時應對突發(fā)事件的嵌入式系統(tǒng)并控制它們。當某些事件發(fā)生時，中斷系統(tǒng)能夠讓信號處理器暫停處理當前的指令序列，并開始了中斷服務。當中斷服務結束之后，再返回原來的指令序列，這就是我們通常所說的單片機的中斷系統(tǒng)。中斷源的設備依賴通常有很多種，如內部定時器溢、完成了模擬向數字轉換、邏輯水平變化的一種投入、一個按鈕被按下和收到了數據的通信聯系等。凡是

47、許多重要的中斷源發(fā)出中斷申請，都必須中斷，如電池供電的設備停止運行后，微控制器在低功耗睡眠狀態(tài)下的處理器必須停止，直到做一些外圍的活動才重新開始返回當前指令序列。</p><p>　　單片機程序必須符合現有的芯片程序存儲器的要求，因為這將是代價高昂的系統(tǒng)提供了與外部設備之間可以擴展的存儲器。編譯器和匯編語言是用來打開高級語言程序到一個緊湊機器代碼存儲在微控制器的存儲過程。根據不同的設備，程式記憶體可能是永久性的，

48、而唯讀存儲器，只能進行編程。在工廠，可以生產可擦除式只讀存儲器。</p><p>　　由于嵌入式處理器通常是用來控制設備的，他們有時需要接受輸入設備的數據輸入，但由于處理器內置處理數數據只有1和0 ，所以它們將無法直接處理任何模擬信號。因此，要先使需要處理的數據通過模擬向數字轉換的過程，才能使傳入的數據轉化為處理器可以識別的形式。還有一種轉換器叫做數模轉換器，他能夠使數字信號轉換為模擬信號并將數據發(fā)送到需要CPU