The development and application of SCM

Single chip microcomputer is integrated the various components on a single silicon chip. With the development of large scale integrated circuit technology,the central processing unit (CPU), data storage (RAM), program memory (ROM)timer counter and input / output (I/O) interface circuit of computer components,integrated on a chip. Although the chip is a chip, but from the composition and the function, has the meaning of microcomputer system. As the microcontrollercan independently carry out internal procedures, so it is also called microcontroller (Microcontroller).
SCM since inception, performance in the continuous improvement and perfection,it can not only meet the needs of many applications, but also has thecharacteristics of high integration, strong function, high speed, small size and convenient use, reliable performance, low price etc.. Therefore, it has been widely used in industrial control, smart instrumentation, data acquisition and processing, communication, intelligent interface, business marketing and other fields, and is replacing the existing multi chip microcomputer application systemgradually. The potential of SCM is more and more attention by people, so the more expanded the scope of application of SCM, but also further promote thedevelopment of SCM technology, SCM development history can be divided into three stages.
The first stage (1976-1978): the primary single-chip micro processing stage. The period of single chip with 8 bit CPU, parallel I/O port, 8 bit timing synchronization counter, addressing range 4KB, but no serial port.
The second stage (1978-1982): high performance single chip microcomputerprocessing stage, the period of the single-chip microcomputer with I/O serial port,a multilevel interrupt processing system, 15 bit timing synchronization technology,RAM, ROM capacity is increased, the addressing range up to 64KB.
The third stage (since 1982-) bit single chip microprocessor improved and 16 bit single chip micro processing stage. The application of SCM
Because the SCM has significant advantages, it has become a powerful tool inthe field of science and technology, human life's right-hand man. Its application in various areas, mainly in the following areas:
Application of 1 single chip microcomputer in intelligent instrument
SCM is widely used in a variety of instrumentation, the intelligent instrument, and can improve the degree of automation and the accuracy of the measurement,simplify the hardware structure of the instrument, improve its performance price ratio.
Application of 2 single chip microcomputer in the Mechatronics
The mechanical and electrical integration of mechanical industrial development direction. Electromechanical integration products refers to the integration ofmachinery technology, microelectronic technology, computer technology,mechanical and electrical products with intelligent features, such asmicrocomputer control of 1 Bao Hong: single chip digital clock design bed, drill etc.. As the MCU in the product, can give full play to the advantages of its small size, high reliability, strong function, can greatly improve the degree ofautomation, intelligent machine.
Application of 3 single chip microcomputer in the real-time control
SCM is widely used in real-time control system. For example, in industrial control,aerospace, sophisticated weapons, robots and other real-time control system,can be used as a controller with mcu. The ability of real-time data processing andcontrol functions of SCM, which can keep the system in the best working condition, improve the work efficiency and the quality of the products.
Application of 4 single chip microcomputer in distributed in multi machine system
In the complex system, often adopts distributed system. Multi machine system generally consists of several different functional microcontroller, to complete theirtask, they contact each other through serial communication, coordination. The microcontroller is often used as a terminal in the system, installed in some nodesystem, measurement and control to real-time information. Anti jamming ability ofSCM is of high reliability and strong, so that it can work in the harsh environment of the front.
Application of 5 single chip microcomputer in human life
Since the birth of single-chip, it entered the human life, such as washing machine, refrigerator, electronic toy, radio cassette recorders and other household appliances with MCU, improve intelligence, increase the function, the favorite. SCM will make human life more convenient, comfortable, rich and colorful. 1.3 MCU development trend at present, SCM is a high performance and multiple varieties of the direction of development, its development will be further towards the CMOS, low power consumption, small volume, large capacity, high performance.
In recent years, due to the CHMOS technology into a small, greatly promoted the single chip microcomputer CMOS. The CMOS chip in addition to low power consumption characteristics, controllable also has the power, the microcontroller can work in the power management state. This is also the future to replace 80C51 8051 as the standard MCU chip. Because the microcontroller chip most is the use of CMOS (metal oxide semiconductor) process. The characteristics of CMOS circuits is low power consumption, high density, low speed, low price. TTL circuit speed using bipolar semiconductor process faster, but the power consumption and chip area. Along with the technical and technological level, and the emergence of HMOS (high density, high speed MOS), combined with CHMOS technology and the CHMOS and HMOS technology. The current CHMOS circuit production has reached the speed of LSTTL, transmission delay time is less than 2ns, its comprehensive advantages has been greater than the TTL circuit. Therefore, in the field of SCM, CMOS circuit is gradually replacing TTL circuit.
2 low power consumption
Single chip power from mA level, or even below 1uA; the use of voltage between 36V, fully meet the battery work. Effects of low power consumption is not only the low power consumption, but also brings high reliability, high resistance
3 low voltage
Almost all the SCM has WAIT, STOP power-saving operation mode. Allowable voltage range more and use more wide, generally work in the range of 36V. Single chip power supply low voltage supply is up to 12V. The 0.8V powered microcontroller has come out.
4 low noise and high reliability
In order to improve the anti electromagnetic interference ability of MCU, so that products can adapt to the harsh working environment, to meet the higher standards of electromagnetic compatibility requirements, the chip manufacturers have adopted the new measures in the internal circuit in single chip microcomputer. 1.4 digital clock scheme comparison of 1.4.1 digital circuit and SCM performance comparison of digital clock system can be implemented by digital circuit, also can use the microcontroller to complete. If done by digital circuit, the circuit design is quite complicated, probably more than ten digital integrated block, the function module combination and its function mainly depend on the digital circuit to realize, the welding process is complicated, the cost is very high. If you use the SCM to design completed, due to the realization of its function is mainly completed through software programming, it reduces the complexity of hardware circuit, and the cost is reduced, so the use of AT89S52 microcontroller in the design and production, it is the CMOS of low power consumption, high performance 8 bit MCU, Flash program memory with the 8KB, and allows the rewriting or programmer in the system. In addition, instruction system and the pins of the AT89S52 is fully compatible with the 8051, the chip has 256B RAM, 32 I / O lines, 2 16 bit timer counter.
1.4.2 digital tube and LCD liquid crystal display performance comparison
Single chip microcomputer application system display the most commonly used LED (light emitting diode display) and LCD (liquid crystal display), the two display device can display numbers, character and the state of the system, they drive circuit is simple, easy to realize and the price is low, so it has been widely applied. At the same time as digital tube can display digital tube digital display the contents of a single, liquid crystal display with its low power consumption, small size, show many advantages of rich content, thin and light, no electromagnetic radiation, the advantages of long service life, to get more and more widely used in portable instruments and low power application system, this graduation design in the functional requirements, more, in order to make the circuit shows more clear, in the design we decided to use LCD1602 as a liquid crystal display device we singlechip digital clock. Bao Hong: 4 singlechip digital clock design.
The design and Realization of the hardware system
This system is composed of AT89S52 single chip microcomputer as control core, with the online programming function, low power consumption, can be in 3V ultra low work environment; clock circuit consists of the external crystal to provide internal clock circuit, it is can be adjusted at any time clock circuit of a high performance, low power consumption, with RAM, the working voltage is 3V ~ 5V using DS1302 as calendar chip; so this design; display part use LCD1602B LCD digital display, 1602B LCD module can display 2 lines of 16 characters, 8 bit data bus D0 - D7 and RS, R/W, EN three control port, the working voltage is 5V, and with the character contrast adjustment and backlight. The module can also use D4-D7 as a four bit data two times transmitting, so it can save MCU of the I/O resource.
Each boot to re set the standard time, inconvenient use and occupation of single-chip timer resources, direct programming chip clock circuit while saving the cost, but there are insufficient, and SCM is not very stable, easy to crash, ran the wrong and so on, a reset circuit is also from the new adjustment time, obviously this is very troublesome in the actual situation, and the mainstream of development of society -- intelligent, is not consistent. But USA DALLAS company has low power consumption real-time clock circuit DS1302 small trickle charge current capacity, it can be years, months, days, weeks, days, hours, minutes, seconds for time, and has a leap year compensation and other functions. The serial data transmission, can provide the charging function programmable power down protection for the power supply, and can turn off the charging function, so here we will use the DS1302 as the clock chip our single-chip digital clock.
1.4.3 microcontroller programming clock and clock chip performance comparison
In the process of application of MCU system, often need a clock circuit timing, control purposes; there are many kinds of method to realize the digital clock, the simplest is to use integrated chip timer, through software programming to constitute a clock to use, but based on this method, the timer in interrupt mode, it is frequently interrupted by the work of CPU.

单片机的应用与发展

单片机是各部件集成在一块芯片上。随着大规模集成电路技术的发展，中央处理单元，数据存储器，程序存储器和定时器计数器输入/输出接口电路等主要计算机组件，集成在一个芯片。虽然芯片是一个芯片，但组成和功能，有一个电脑系统。由于单片机可以独立执行内部程序，所以它也被称为微控制器。
单片机问世以来，在不断的改进和完善的性能，它不仅能满足许多应用的需要，而且还具有集成度高，功能强，速度快，体积小],性能可靠，使用方便，价格低廉等特点。因此，广泛应用于工业控制，智能化仪器仪表，数据采集与处理，通信，智能接口，业务营销和其他领域，并逐步取代现有的多单片机应用系统。单片机的潜力越来越受到人们的重视，因此，更扩大了范围的微控制器的应用,进一步促进了计算机技术的发展，对单片机的发展历史大致可以分为三个阶段。
第一阶段（1976-1978年）：初级单片机微处理阶段,随着8位CPU芯片的时期，并行I/O端口，8位的定时同步计数器，寻址4KB的范围，但没有串口。
第二阶段（1978-1982年）：高性能单片机处理阶段，这个时间与I / O单片机串行口，一个多级中断处理系统，15位的定时同步技术，RAM，ROM容量增加，寻址范围可达64KB。
第三阶段（自1982）位单片机微处理的改进和16位单片微处理阶段。单片机应用
由于单片机具有显著的优点，它已成为在科学和技术领域的一个强大的工具，人类生活的得力助手。它在各个领域的应用，主要在以下几个方面：
1单片机在智能仪表中的微机应用
单片机广泛应用于各种仪表，智能仪表，并能提高自动化程度和精度，简化了仪器的硬件结构，提高性能价格比。
2单片机在机电一体化中的应用。
机电一体化是机械行业的发展方向。机电一体化产品指的是机械技术，微电子技术的集成，计算机技术，机电产品具有智能功能，如微机控制1堡红：单片机数字钟的设计，钻井和其他床。单片机作为控制器的产品，可以充分发挥其体积小，可靠性高的优点，功能强大，可以大大提高自动化程度，智能机。
3 单片机在实时控制中的应用
单片机广泛地用于各种实时控制系统中。例如，在工业测控、航空航天、尖端武器、机器人等各种实时控制系统中，都可以用单片机作为控制器。单片机的实时数据处理能力和控制功能，可使系统保持在最佳工作状态，提高系统的工作效率和产品质量。
 4 单片机在分布式多机系统中的应用
在比较复杂的系统中，常采用分布式多机系统。多机系统一般由若干台功能各异的单片机组成，各自完成特定的任务，它们通过串行通信相互联系、协调工作。单片机在这种系统中往往作为一个终端机，安装在系统的某些节点上，对现场信息进行实时的测量和控制。单片机的高可靠性和强抗干扰能力，使它可以置于恶劣环境的前端工作。
5 单片机在人类生活中的应用
自从出生后的芯片，它已进入人类生活，如洗衣机，冰箱，电子玩具，录音机等家用电器的控制器，提高智力，增加功能，非常受欢迎。单片机将让人类的生活更方便，舒适，丰富多彩的。1.3单片机的发展趋势目前，单片机是一款高性能、多样化的发展方向，趋势将进一步向着CMOS，低功耗，小体积，大容量，高性能。
近年来，由于CHMOS技术为小，极大地促进了单片机的CMOS。除了低功耗CMOS芯片的特点，还具有功率控制，单片机可以工作在功耗精细管理。这是用80C51的而不是8051标准的MCU芯片的未来。因为大部分的芯片的CMOS（金属氧化物半导体）工艺。CMOS电路的特点是低功耗，高密度，低转速，低价格。TTL电路采用双极性半导体工艺的速度更快，但功耗和芯片面积较大。随着技术和工艺水平，和HMO的出现（高密度，高速MOS），结合CHMOS技术和CHMOS和医疗技术。CHMOS电路的生产已达到输入通道的速度快，传输延迟时间小于2ns，其综合优势已大于TTL电路。因此，在单片机领域，CMOS电路逐渐由TTL电路取代。
2低功耗
从马单片机功率水平，甚至低于1uA；电压36V之间使用，完全满足电池。低功率消耗的影响不仅功耗低，可靠性高，但也带来了高康产品
3低电压
几乎所有的单片机等，停止省电模式。让更多的和更宽的电压范围内使用，一般在36V范围。单片机的低压电源已高达12V的下限。目前0.8V供电的微控制器已经被公布。               4低噪声与高可靠性
    为了提高单片机抗电磁干扰的能力，使产品能适应恶劣的工作环境，满足电磁兼容性要求更高的标准，芯片制造商已经在单片机内部电路采用新的技术措施。1.4的数字时钟演示程序1.4.1数字电路和单片机的数字时钟系统的性能比较，可用于数字电路，也可以采用单片机来完成。如果用数字电路，该电路是相当复杂的，大约有十几个数字集成块，功能模块的组合，其功能也主要取决于实现数字电路，焊接过程越复杂，成本很高。如果单片机来设计完成的使用，因为它的功能是通过软件编程主要完成，从而降低了硬件电路的复杂性，降低了成本，因此在与CMOS型设计制造的AT89S52单片机，它是一种高性能、低功耗的8位单片机，具有8KB Flash程序存储器，并允许程序员重写或在系统中的应用。此外，指令集和引脚与AT89S52 8051兼容，该芯片具有256B RAM，32个I/O口线，2个16位定时器计数器。
1.4.2数码管和液晶显示器的性能比较
单片机应用系统的显示最常用的LED（发光二极管显示）和LCD（液晶显示器），这两种显示设备可以显示数字，字符和系统状态，电路简单，易于实现，价格较低，因此得到了广泛的应用。同时，由于数码管可以显示数码管显示数字内容单一，液晶显示器以其微功耗，体积小，显示内容丰富等众多优点，轻薄，无电磁辐射，使用寿命长等优点，得到越来越广泛的应用便携式仪器的低功耗应用，本毕业设计在功能上的要求，更多的，为了使电路的显示更加清晰，在设计中我们决定使用LCD1602作为液晶显示装置的单片机的数字钟。宝红：4单片机数字钟的设计
1.4.3单片机编程的时钟和时钟芯片的性能比较
在单片机系统中的应用过程中，往往需要一个时钟电路的时序，并使用；有许多方法来实现数字钟，最简单的是集成定时器单片机的使用，通过软件编程来形成一个时钟使用，但基于这一方法，定时器中断方式中断由CPU，它会工作。
每次开机重新设定标准时间，使用不方便，利用单片机的定时器资源占用，直接编程的单片机时钟电路，节约了成本，但存在不足，该芯片是不是很稳定，很容易崩溃，跑错等等，一个新的电路复位也从调整时间，显然这是非常困难的实际情况，和主流社会的发展——智能，是不一致的。但美国达拉斯公司推出的一种低功耗实时时钟电路DS1302涓流充电电流的能力，它可以是年，月，日，周，日，小时，分钟，秒的时间，并且具有闰年补偿等功能。串行数据传输，可为掉电保护功能的可编程充电电源，可以关闭充电功能，所以在这里我们将使用DS1302作为时钟芯片单片机数字钟的我们。
硬件系统的设计与实现
该系统由AT89S52单片机为控制核心，通过在线编程功能，功耗低，可以在3V的超低气压环境；通过一个内部时钟电路的外部晶体振荡器的时钟电路提供时钟电路是可以调整的，它始终是一种高性能，低内存消耗功率，工作电压为3V，5V ~；所以DS1302芯片作为一个万年历的设计；显示部分采用LCD1602B的液晶数字显示，1602b液晶显示模块，可以显示2行16字，d0-d7和RS 8位数据总线，R/W，EN三控制端口，工作电压为5V，并与字符对比度调节和背光。该模块可作为一四位D4-D7数据分成两个传输，这样可以节省单片机的I/O资源。