单片机课程设计英文参考文献.pdf

ABOUT SCMIt can be said across the twentieth century, the three electric era, that is, electricalera, the electronic age, and has now entered the computer age. However, such acomputer, usually refers to the personal computer, referred to as PC. It consists of thehost, keyboard, monitor etc. Another type of computer, most people do not know how.This computer is to smart to give a variety of mechanical microcontroller (also known asmicro-controller). As the name suggests, this computer system only used the smallest oneIC, you can perform simple operations and control. Because of its small size, usuallyhidden in a charged mechanical stomach Lane. It is the entire device, like the humanbrain plays a role, it goes wrong, the whole device was paralyzed.Now, this MCU has a very wide field of use, such as smart meters, real-time industrialcontrol, communications equipment, navigation systems, home appliances and so on.Once the microcontroller were using a variety of products, you can serve to upgrade theeffectiveness of the product, often in the product name is preceded by the adjective -smart, such as washing machines and so intelligent. At present, some technicalpersonnel of factories or other amateur electronics developers to engage in out of certainproducts, not the circuit is too complex, that is, functions are too simple and easy to becopied. The reason may be stuck in the product without the use of a microcontroller orother programmable logic device.SCM basic component is a central processing unit (CPU in the computing device andcontroller), read-only memory (usually expressed as a ROM), read-write memory (alsoknown as Random Access Memory MRAM is usually expressed as a RAM) , input / outputport (also divided into parallel port and serial port, expressed as I / O port), and socomposed. In fact there is also a clock circuit microcontroller, so that during operation andcontrol of the microcontroller, can rhythmic manner. In addition, there are so-called breaksystem, the system is a janitor role, when the microcontroller control object parametersthat need to be intervention to reach a particular state, can after this janitorcommunicated to the CPU, so that CPU priorities of the external events to takeappropriate counter-measures.Electric boiler temperature system1.MCUA microcontroller (or MCU) is a computer-on-a-chip. It is a type of microprocessoremphasizing self-sufficiency and cost-effectiveness, in contrast to a general-purposemicroprocessor (the kind used in a PC).The majority of computer systems in use today areembedded in other machinery,such as telephones, clocks, appliances, vehicles, and infrastructure. An embeddedsystem usually has minimal requirements for memory and program length and mayrequire simple but unusual input/output systems. For example, most embedded systemslack keyboards, screens, disks, printers, or other recognizable I/O devices of a personalcomputer. They may control electric motors, relays or voltages, and read switches,variable resistors or other electronic devices. Often, the only I/O device readable by ahuman is a single light-emitting diode, and severe cost or power constraints can eveneliminate that.In contrast to general-purpose CPUs, microcontrollers do not have an address bus ora data bus, because they integrate all the RAM and non-volatile memory on the same chipas the CPU. Because they need fewer pins, the chip can be placed in a much smaller,cheaper package.Integrating the memory and other peripherals on a single chip and testing them as aunit increases the cost of that chip, but often results in decreased net cost of theembedded system as a whole. (Even if the cost of a CPU that has integrated peripheralsis slightly more than the cost of a CPU + external peripherals, having fewer chips typicallyallows a smaller and cheaper circuit board, and reduces the labor required to assembleand test the circuit board). This trend leads to design.A microcontroller is a single integrated circuit, commonly with the following features:central processing unit - ranging from small and simple 4-bit processors to sophisticated32- or 64-bit processorsinput/output interfaces such as serial ports (UARTs)other serial communications interfaces like IC, Serial Peripheral Interface and ControllerArea Network for system interconnectperipherals such as timers and watchdogRAMfor data storage ROM, EPROM, EEPROM or Flash memory for program storageclockgenerator - often an oscillator for a quartz timing crystal, resonator or RC circuit manyinclude analog-to-digital converters .This integration drastically reduces the number of chips and the amount of wiring andPCB space that would be needed to produce equivalent systems using separate chipsand have proved to be highly popular in embedded systems since their introduction in the1970s.Some microcontrollers can afford to use a Harvard architecture: separate memorybuses for instructions and data, allowing accesses to take place concurrently.The decision of which peripheral to integrate is often difficult. The Microcontrollervendors often trade operatingfrequencies and system designflexibility againsttime-to-market requirements from their customers and overall lower system cost.Manufacturers have to balance the need to minimize the chip size against additionalfunctionality.Microcontroller architectures are available from many different vendors in so manyvarieties that each instruction set architecture could rightly belong to a category of theirown. Chief among these are the 8051, Z80 and ARM derivatives.citation neededA microcontroller (also MCU or C) is a functional computer system-on-a-chip. Itcontains a processor core, memory, and programmable input/output peripherals.Microcontrollers include an integrated CPU, memory (a small amount of RAM, programmemory, or both) and peripherals capable of input and output.It emphasizes high integration, in contrast to a microprocessor which only contains aCPU (the kind used in a PC). In addition to the usual arithmetic and logic elements of ageneral purpose microprocessor, the microcontroller integrates additional elements suchas read-write memory for data storage, read-only memory for program storage, Flashmemory for permanent data storage, peripherals, and input/output interfaces. At clockspeeds of as little as 32KHz, microcontrollers often operate at very low speed comparedto microprocessors, but this is adequate for typical applications. They consume relativelylittle power (milliwatts or even microwatts), and will generally have the ability to retainfunctionality while waiting for an event such as a button press or interrupt. Powerconsumption while sleeping (CPU clock and peripherals disabled) may be just nanowatts,making them ideal for low power and long lasting battery applications.Microcontrollers are used in automatically controlled products and devices, such asautomobile engine control systems, remote controls, office machines, appliances, powertools, and toys. By reducing the size, cost, and power consumption compared to a designusing a separate microprocessor, memory, and input/output devices, microcontrollersmake it economical to electronically control many more processes.The majority of computer systems in use today are embedded in othermachinery,such as automobiles, telephones, appliances, and peripherals for computer systems.These are called embedded systems. While some embedded systems are verysophisticated, many have minimal requirements for memory and program length, with nooperating system, and low software complexity. Typical input and output devices includeswitches, relays, solenoids, LEDs, small or custom LCD displays, radio frequency devices,and sensors for data such as temperature, humidity, light level etc. Embedded systemsusually have no keyboard, screen, disks, printers, or other recognizable I/O devices of apersonal computer, and may lack human interaction devices of any kind.It is mandatory that microcontrollers provide real time response to events in theembedded system they are controlling. When certain events occur, an interrupt systemcan signal the processor to suspend processing the current instruction sequence and tobegin an interrupt service routine (ISR). The ISR will perform any processing requiredbased on the source of the interrupt before returning to the original instruction sequence.Possible interrupt sources are device dependent, and often include events such as aninternal timer overflow, completing an analog to digital conversion, a logic level change onan input such as from a button being pressed, and data received on a communication link.Where power consumption is important as in battery operated devices, interrupts mayalso wake a microcontroller from a low power sleep state where the processor is halteduntil required to do something by a peripheral event.Microcontroller programs must fit in the available on-chip program memory, since itwould be costly to provide a system with external, expandable, memory. Compilers andassembly language are used to turn high-level language programs into a compactmachine code for storage in the microcontrollers memory. Depending on the device, theprogram memory may be permanent, read-only memory that can only be programmed atthe factory, or program memory may be field-alterable flash or erasable read-onlymemory.Since embedded processors are usually used to control devices, they sometimesneed to accept input from the device they are controlling. This is the purpose of the analogto digital converter. Since processors are built to interpret and process digital data, i.e. 1sand 0s, they wont be able to do anything with the analog signals that may be being sent toit by a device. So the analog to digital converter is used to convert the incoming data into aform that the processor can recognize. There is also a digital to analog converter thatallows the processor to send data to the device it is controlling.In addition to the converters, many embedded microprocessors include a variety oftimers as well. One of the most common types of timers is the Programmable IntervalTimer, or PIT for short. A PIT just counts down from some value to zero. Once it reacheszero, it sends an interrupt to the processor indicating that it has finished counting. This isuseful for devices such as thermostats, which periodically test the temperature aroundthem to see if they need to turn the air conditioner on, the heater on, etc.Time Processing Unit or TPU for short. Is essentially just another timer, but moresophisticated. In addition to counting down, the TPU can detect input events, generateoutput events, and other useful operations.Dedicated Pulse Width Modulation (PWM) block makes it possible for the CPU tocontrol power converters, resistive loads, motors, etc., without using lots of CPUresources in tight timer loops.Universal Asynchronous Receiver/Transmitter (UART) block makes it possible toreceive and transmit data over a serial line with very little load on the CPU.For those wanting ethernet one can use an external chip like Crystal SemiconductorCS8900A, Realtek RTL8019, or Microchip ENC 28J60. All of them allow easy interfacingwith low pin count.中文翻译：可以说，二十世纪跨越了三个“电”的时代， 即电气时代、电子时代和现已进入的电脑时代。不过，这种电脑，通常是指个人计算机，简称PC 机。它由主机、键盘、显示器等组成。还有一类计算机，大多数人却不怎么熟悉。 这种计算机就是把智能赋予各种机械的单片机（亦称微控制器）。顾名思义，这种计算机的最小系统只用了一片集成电路，即可进行简单运算和控制。因为它体积小，通常都藏在被控机械的“肚子”里。它在整个装置中， 起着有如人类头脑的作用，它出了毛病，整个装置就瘫痪了。现在，这种单片机的使用领域已十分广泛，如智能仪表、实时工控、通讯设备、导航系统、家用电器等。各种产品一旦用上了单片机， 就能起到使产品升级换代的功效， 常在产品名称前冠以形容词“智能型”， 如智能型洗衣机等。 现在有些工厂的技术人员或其它业余电子开发者搞出来的某些产品，不是电路太复杂，就是功能太简单且极易被仿制。究其原因，可能就卡在产品未使用单片机或其它可编程逻辑器件上。单片机的基本组成是由中央处理器（即CPU 中的运算器和控制器）、只读存贮器（通常表示为 ROM）、读写存贮器（又称随机存贮器通常表示为RAM）、输入/输出口（又分为并行口和串行口，表示为I/O 口）等等组成。实际上单片机里面还有一个时钟电路， 使单片机在进行运算和控制时， 都能有节奏地进行。 另外， 还有所谓的“中断系统”， 这个系统有“传达室”的作用， 当单片机控制对象的参数到达某个需要加以干预的状态时， 就可经此“传达室”通报给 CPU，使 CPU 根据外部事态的轻重缓急来采取适当的应付措施。单片机即单片微型计算机，是把中央处理器、存储器、定时/计数器、输入输出接口都集成在一块集成电路芯片上的微型计算机。 与应用在个人电脑中的通用型微处理器相比， 它更强调自供应（不用外接硬件）和节约成本。它的最大优点是体积小，可放在仪表内部，但存储量小，输入输出接口简单，功能较低。由于其发展非常迅速， 旧的单片机的定义已不能满足， 所以在很多应用场合被称为范围更广的微控制器， 但是目前在中国大陆仍多沿用“单片机”的称呼。绝大多数现在的单片机都是基于冯诺伊曼结构的， 这种结构清楚地定义了嵌入式系统所必需的四个基本部分：一个中央处理器核心，程序存储器（只读存储器或者闪存） 、数据存储器（随机存储器） ，一个或者更多的定时/计时器，还有用来与外围设备以及扩展资源进行通信的输入/输出端口所有这些都被集成在单个集成电路芯片上。说单片机与通用型中央处理单元芯片不同是因为前者一般很容易配合最小型的外部支持芯片制成工作计算机。这样就可以很容易的把单片机系统植入装置内部来控制装置了。 近年来为了在指令和数据上使用不同的字宽， 并提高处理器流水线速度， 哈佛结构在微控制器和 DSP 也逐渐得到了广泛的应用。传统的微处理器是不允许这么做的。 它要完成单片机的工作， 就必须连接一些其他芯片。比如说，片上没有数据存储器，就必须要添加一些 RAM 的存储芯片，虽然所添加存储器的容量很灵活，但是至少还是要添加， 另外还需要添加很多连线来传递芯片之间的数据。 比如，一个典型的微控制器只需要一个时钟发生器和很少的RAM 和 ROM(或者 EPROM, E2PROM)就可以在软件和晶振下工作了。同时，微控制器具有丰富的输入输出设备，像是模拟数字转换(ADC)， 定时器， 串口或者其他串行通讯接口(比如 I2C， 串行外围接口(SPI),控制器局域网)。通常，这些继承在内部的设备可以通过特殊的指令来操作。一些现代的微控制器支持一些内建的高级编程语言，比如BASIC 语言。一个微控制器（也叫MCU）是一个微型计算芯片。它包含一个处理器、一个内存（有少量的 RAM ，程序存储器，或两者兼而有之）和一个可编程输入/输出外设。它强调高度集成，而相比之下，一个微处理器只包含一个CPU （比如一台 PC ） 。除了通常的算术和逻辑要素等一般用途的微处理器， 微控制器还集成了更多的要素， 如读写存储器的数据存储，只读存储器的存储程序，快闪记忆体的永久数据存储，外设，和输入/输出接口。在时钟频率只有 32Mhz 的情况下 ，微操作系统往往以非常低的速度相运行，但是这足够典型的应用。他们消耗较少的功率（毫瓦或什微） ，且具有保持功能，同时可以等待一个事件，如一个按钮的按下或中断。在睡眠状态时， CPU 时钟和外设禁用，从而使它们适合用于低功耗和长期持久的电池应用。微控制器广泛应用于自动控制产品和设备， 如汽车发动机控制系统， 远程控制系统，办公室机器设备系统，家用电器，电动工具，和玩具等。通过降低尺寸，成本和能耗，设计使用单独的微处理器，内存和输入/输出设备，能够使微控制器控制更多的进程，更经济。目前，大多数的计算机系统被嵌入在其他设备中使用，如汽车，电话以及很多需要外设的计算机系统。 这些嵌入其他设备的计算机系统被称为嵌入式系统。 有些嵌入式系统是非常复杂的，很多能够达到人们的要求， 但由于内存和程序长度的限制，软件的复杂性降低。典型的输入和输出设备包括交换机， 继电器， 螺线管， 发光二极管， 小形或定制的液晶显示器，数码显示器等。射频设备和传感器等嵌入式系统通常没有键盘，屏幕， 硬盘，打印机或其他公认的 I / O 设备，并可能缺乏人机互动装置的任何一种。某些强制性的微控制器能够提供实时应对突发事件的嵌入式系统并控制它们。 当某些事件发生时，中断系统能够让信号处理器暂停处理当前的指令序列， 并开始了中断服务。当中断服务结束之后，再返回原来的指令序列， 这就是我们通常所说的单片机的中断系统。 中断源的设备依赖通常有很多种， 如内部定时器溢、完成了模拟向数字转换、 逻辑水平变化的一种投入、 一个按钮被按下和收到了数据的通信联系等。 凡是许多重要的中断源发出中断申请，都必须中断， 如电池供电的设备停止运行后， 微控制器在低功耗睡眠状态下的处理器必须停止，直到做一些外围的活动才重新开始返回当前指令序列。单片机程序必须符合现有的芯片程序存储器的要求， 因为这将是代价高昂的系统提供了与外部设备之间可以扩展的存储器。 编译器和汇编语言是用来打开高级语言程序到一个紧凑机器代码存储在微控制器的存储过程。 根据不同的设备，程式记忆体可能是永久性的， 而唯读存储器，只能进行编程。在工厂，可以生产可擦除式只读存储器。由于嵌入式处理器通常是用来控制设备的， 他们有时需要接受输入设备的数据输入， 但由于处理器内置处理数数据只有1 和 0 ，所以它们将无法直接处理任何模拟信号。因此，要先使需要处理的数据通过模拟向数字转换的过程， 才能使传入的数据转化为处理器可以识别的形式。 还有一种转换器叫做数模转换器， 他能够使数字信号转换为模拟信号并将数据发送到需要 CPU 控制的设备上，以达到控制的目的。此外， 许多嵌入式微处理器包括各种兼职的转换器。 最常见的一种类型的转换器是可编程间隔定时转换器。 工作过程为一个倒计时刚到达零， 它就会对处理器发出一个中断的指令。这表明它已经完成转换， 并需要对所控制的设备发出指令， 使其作出某些动作。这是非常有用的设备，如恒温系统，需要定期测试他们周围的温度， 看看他们是否需要打开空调或者加热器等等。