为了提高传统温度控制系统的性能，将PID控制理论与嵌入式系统相结合，采用瑞萨电子公司的H8S/2166作为核心处理器，AD公司的AD7705以及热敏电阻温度传感器作为温度检测单元，利用4&Times;6小键盘、LCD显示器和S1D13305液晶控制器达到良好的人机交互，设计出了一个应用于化工领域的嵌入式实时温度控制系统。相比于传统温度控制系统，该系统提供了更强的计算能力和可扩展能力，采用增量PID控制算法实现复杂控制。通过实验，该系统能达到0.1 ℃的温度控制精度以及小于120 s的温度稳定时间。 Abstract: In order to improve the performance of conventional temperature control system， combining PID control theory with embedded systems， using the Renesas Electronics Corp. H8S/2166 micro-controller as a core processors， AD7705 and thermistor temperature sensor as a temperature detection unit and 4&Times;6 small keyboard， LCD and S1D13305 LCD controller as a good human-computer interaction， this paper designed an embedded real-time temperature control system which is applied in chemical industry. Compared with conventional temperature control system， this system provides more computing power and extensibility， and adopts PID control algorithm for complex control. Through the experiment， the system can reach temperature control accuracy of 0.1 ℃ and temperature stabilization time of less than 120 seconds.
上传时间： 2014-12-26
上传用户：003030
目录： 1. Character Type Functions － 字符类型函数 2. Standard C Input/Output Functions － 标准输入输出函数 3. Standard Library Functions － 标准库和内存分配函数 4. Mathematical Functions － 数学函数 5. String Functions － 字符串函数 6. BCD Conversion Functions － BCD 转换函数 7. Memory Access Functions － 存储器访问函数 8. Delay Functions － 延时函数 9. LCD Functions － LCD函数 10. LCD Functions for displays with 4x40 characters － 4&Times;40 字符型LCD函数 11. LCD Functions for displays connected in 8 bit memory mapped mode －以8 位外部存储 器模式接口的LCD显示函数 12. I2C Bus Functions － I2C 总线函数 13. National Semiconductor LM75 Temperature Sensor Functions － LM75 温度传感器函数 14. Dallas Semiconductor DS1621 Thermometer/Thermostat Functions － DS1621 温度计函 数 15. Philips PCF8563 Real Time Clock Functions － PCF8563 实时时钟函数 16. Philips PCF8583 Real Time Clock Functions － PCF8583 实时时钟函数 17. Dallas Semiconductor DS1302 Real Time Clock Functions － DS1302 实时时钟函数 18. Dallas Semiconductor DS1307 Real Time Clock Functions － DS1307 实时时钟函数 19. 1 Wire Protocol Functions － 单线通讯协议函数 20. Dallas Semiconductor DS1820/DS1822 Temperature Sensors Functions － DS1820/1822 温度传感器函数 21. SPI Functions － SPI 函数 22. Power Management Functions － 电源管理函数 23. Gray Code Conversion Functions － 格雷码转换函数
上传时间： 2013-10-21
上传用户：归海惜雪
介绍以P87LPC764型单片机为核心的延时型漏电继电器设计方案。该方案可供用户选择实现额定动作电流和5倍额定动作电流下不同的延时动作时间，并有重合闸设定选择功能。解决了以往传统分立元件带来的延时时间离散性大且不易实现的弊端。 Abstract: In this paper, the delay leakage relay based on P87LPC764 is introduced in detail. This system provides different relay Times at rating current and 5× rating current for users and also offers superposition brake set selection function. So that it resolves many traditional problems.
上传时间： 2013-11-07
上传用户：zhaiye
Although Stellaris microcontrollers have generous internal SRAM capabilities, certain applicationsmay have data storage requirements that exceed the 8 KB limit of the Stellaris LM3S8xx seriesdevices. Since microcontrollers do not have an external parallel data-bus, serial memory optionsmust be considered. Until recently, the ubiquitous serial EEPROM/flash device was the only serialmemory solution. The major limitations of EEPROM and flash technology are slow write speed, slowerase Times, and limited write/erase endurance.Recently, serial SRAM devices have become available as a solution for high-speed dataapplications. The N256S08xxHDA series of devices, from AMI Semiconductor, offer 32 K x 8 bits oflow-power data storage, a fast Serial Peripheral Interface (SPI) serial bus, and unlimited write cycles.The parts are available in 8-pin SOIC and compact TSSOP packages.
上传时间： 2013-10-14
上传用户：cxl274287265
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall Times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.For input signals, which do not provide the required rise/fall Times, external circuitry mustbe used to shape the signal transitions.In the attached diagram, the effect of the sample rate is shown. The numbers 1 to 5 in thediagram represent possible sample points. Waveform a) shows the result if the inputsignal transition time through the undefined TTL-level area is less than the time distancebetween the sample points (sampling at 1, 2, 3, and 4). Waveform b) can be the result ifthe sampling is performed more than once within the undefined area (sampling at 1, 2, 5,3, and 4).Sample points:1. Evaluation of the signal clearly results in a low level2. Either a low or a high level can be sampled here. If low is sampled, no transition willbe detected. If the sample results in a high level, a transition is detected, and anappropriate action (e.g. capture) might take place.3. Evaluation here clearly results in a high level. If the previous sample 2) had alreadydetected a high, there is no change. If the previous sample 2) showed a low, atransition from low to high is detected now.
上传时间： 2013-10-23
上传用户：copu
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall Times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.
上传时间： 2014-04-02
上传用户：han_zh
近年来随着科技的飞速发展，单片机的应用正在不断深入，同时带动传统控制检测技术日益更新。在实时检测和自动控制的单片机应用系统中，单片机往往作为一个核心部件来使用，仅单片机方面知识是不够的，还应根据具体硬件结构软硬件结合，加以完善。 十字路口车辆穿梭，行人熙攘，车行车道，人行人道，有条不紊。那么靠什么来实现这井然秩序呢？靠的就是交通信号灯的自动指挥系统。交通信号灯控制方式很多。本系统采用MSC-51系列单片机ATSC51和可编程并行I/O接口芯片8255A为中心器件来设计交通灯控制器，实现了能根据实际车流量通过8051芯片的P1口设置红、绿灯燃亮时间的功能；红绿灯循环点亮，倒计时剩5秒时黄灯闪烁警示（交通灯信号通过PA口输出，显示时间直接通过8255的PC口输出至双位数码管）；车辆闯红灯报警；绿灯时间可检测车流量并可通过双位数码管显示。本系统实用性强、操作简单、扩展功能强。 程序源代码 ORG 0000H ;主程序的入口地址 LJMP MAIN ;跳转到主程序的开始处 ORG 0003H ;外部中断0的中断程序入口地址 ORG 000BH ;定时器0的中断程序入口地址
上传时间： 2013-12-21
上传用户：1234321@q
This white paper discusses how market trends, the need for increased productivity, and new legislation have accelerated the use of safety systems in industrial machinery. This TÜV-qualified FPGA design methodology is changing the paradigms of safety designs and will greatly reduce development effort, system complexity, and time to market. This allows FPGA users to design their own customized safety controllers and provides a significant competitive advantage over traditional microcontroller or ASIC-based designs. Introduction The basic motivation of deploying functional safety systems is to ensure safe operation as well as safe behavior in cases of failure. Examples of functional safety systems include train brakes, proximity sensors for hazardous areas around machines such as fast-moving robots, and distributed control systems in process automation equipment such as those used in petrochemical plants. The International Electrotechnical Commission’s standard, IEC 61508: “Functional safety of electrical/electronic/programmable electronic safety-related systems,” is understood as the standard for designing safety systems for electrical, electronic, and programmable electronic (E/E/PE) equipment. This standard was developed in the mid-1980s and has been revised several Times to cover the technical advances in various industries. In addition, derivative standards have been developed for specific markets and applications that prescribe the particular requirements on functional safety systems in these industry applications. Example applications include process automation (IEC 61511), machine automation (IEC 62061), transportation (railway EN 50128), medical (IEC 62304), automotive (ISO 26262), power generation, distribution, and transportation. 图Figure 1. Local Safety System
上传时间： 2013-11-05
上传用户：维子哥哥
Fastwel是一款基于AMD Geode LX800（500MHz）处理器的单板计算机，PC\104支持PCI（32位和16位ISA）。支持Linux，嵌入式Windows XP，QNX。CPB905的所有组件，包括CPU和板载内存均使用焊接从而提供高抗振性。并有一组丰富的接口：2个快速以太网端口，7个COM端口，4个USB2.0端口，支持视频输出（CRT，TFT，LVDS），分辨率高达1920&Times;1440像素。
上传时间： 2013-11-12
上传用户：dengzb84
论述了汉字显示的基本原理,基于OpenGL提出了在VxWorks嵌入式系统中汉字输入及显示的实现方案,并以16&Times;16点阵字库为例,给出了关键程序设计。通过该输入法的输入及显示,结果表明,OpenGL提供了一种直观的编程环境,以及一系图形变换和外部设备访问函数,使开发者可以方便地访问鼠标、键盘等外设,简化了图形程序开发。
上传时间： 2013-11-03
上传用户：tou15837271233
