本文介绍了基于AT89C52 单片机的自动水温控制系统的设计及实现过程。该系统具有实时显示、温度测量、温度设定并能根据设定值对环境温度进行调节实现控温的目的以及达到上下限温度报警功能，控制算法是基于数字PID 算法。关键词 ：PID AT89C52 脉宽调制 实时 Abstract ： This article describes AT89C52 single-chip microcomputer-basedautomatic water temperature control system design and implementation process. Thesystem has real-time display, temperature measurement, temperature settings and theenvironment in accordance with the temperature settings adjusted to achieve thepurpose of temperature control and reach the upper and lower limits of temperaturealarm function, the control algorithm is based on the digital PID algorithm.Keyword: PID AT89C52 PWM real time
上传时间： 2013-10-10
上传用户：归海惜雪
NXP Semiconductor designed the LPC2400 microcontrollers around a 16-bit/32-bitARM7TDMI-S CPU core with real-time debug interfaces that include both JTAG andembedded Trace. The LPC2400 microcontrollers have 512 kB of on-chip high-speedFlash memory. This Flash memory includes a special 128-bit wide memory interface andaccelerator architecture that enables the CPU to execute sequential instructions fromFlash memory at the maximum 72 MHz system clock rate. This feature is available onlyon the LPC2000 ARM Microcontroller family of products. The LPC2400 can execute both32-bit ARM and 16-bit Thumb instructions. Support for the two Instruction Sets meansEngineers can choose to optimize their application for either performance or code size atthe sub-routine level. When the core executes instructions in Thumb state it can reducecode size by more than 30 % with only a small loss in performance while executinginstructions in ARM state maximizes core performance.
上传时间： 2013-11-15
上传用户：zouxinwang
Features• Complete DTMF Receiver• Low power consumption• Internal gain setting amplifier• Adjustable guard time• Central office quality• Power-down mode• Inhibit mode• Backward compatible withMT8870C/MT8870C-1Applications• Receiver system for British Telecom (BT) orCEPT Spec (MT8870D-1)• Paging systems• Repeater systems/mobile radio• Credit card systems• Remote control• Personal computers• Telephone answering machine
上传时间： 2013-11-20
上传用户：mpquest
NEC 16位MCU参考手册 The 78K0R/IC3 is a 16-bit single-chip microcontroller that uses a 78K0R CPU core and incorporates peripheral functions, such as ROM/RAM, a multi-function timer, a multi-function serial interface, an A/D converter, a programmable gain amplifier (PGA), a comparator, a real-time counter, and a watchdog timer.
上传时间： 2013-11-02
上传用户：努力努力再努力
Virtex-5, Spartan-DSP FPGAs Application Note This application note demonstrates how efficient implementations of Digital Up Converters(DUC) and Digital Down Converters (DDC) can be done by leveraging the Xilinx DSP IPportfolio for increased productivity and reduced time to development. Step-by-step instruction is given on how to perform system-level trade off analysis and develop the most efficient FPGA implementation, thus allowing engineers a flexible, low-cost and low-power alternative to ASSP technologies.
标签： Spartan-DSP Virtex FPGAs Ap
上传时间： 2013-10-23
上传用户：raron1989
FeaturesThe following standard features are provided.• Choice of RTOS scheduling policy1. Pre-emptive:Always runs the highest available task. Tasks of identical priorityshare CPU time (fully pre-emptive with round robin time slicing).2. Cooperative:Context switches only occur if a task blocks, or explicitly callstaskYIELD().• Co-routines (light weight tasks that utilise very little RAM).• Message queues• Semaphores [via macros]• Trace visualisation ability (requires more RAM)• Majority of source code common to all supported development tools• Wide range of ports and examples
上传时间： 2013-10-13
上传用户：13162218709
This application note describes how to decode standard DTMF tones using the minimum number of external discrete components and a PIC. The two examples use a PIC which has an 8 bit timer and either a comparator or an ADC, although it can be modified for use on a PIC which has only digital I/O. The Appendices have example code for the 16C662 (with comparator) and 16F877 (using the ADC). As the majority of the Digital Signal Processing is done in software, little is required in the way of external signal conditioning. Software techniques are used to model the individual elements of a DTMF Decoder IC.
上传时间： 2013-11-21
上传用户：zhaoke2005
汇编器在微处理器的验证和应用中举足轻重，如何设计通用的汇编器一直是研究的热点之一。本文提出了一种开放式的汇编器系统设计思想，在汇编语言与机器语言间插入中间代码CMDL（code mapping description language）语言，打破汇编语言与机器语言的直接映射关系，由此建立起一套描述汇编语言与机器语言的开放式映射体系。基于此开放式映射体系开发了一套汇编器系统，具有较高层次上的通用性和可移植性。【关键词】指令集，CMDL，汇编器，开放式 Design of Retargetable Assembler System Liu Ling Feng Wen Nan Wang Ying Chun Jiang An Ping Ji Li Jiu IME of Peking University, 100871【摘要】An assembler plays a very important role in the field of microprocessor verifications and applications, thus how to build a retargetable assembler system has been a hotspot in this field for long time. This paper presents a new method about the retargetable assembler system design.It provides a kind of language CMDL, code mapping description language. During the process of assembling, assembler languages are firstly translated to CMDL, and then mapped to the machine codes. In an other word, CMDL is inserted between assembler languages and machine codes during the translation procedure. As a medium code, CMDL has a lot of features, such as high extraction, strong descript capabilities. It can describe almost all attributes of assembler languages. By breaking the direct mapping relationship between assembler languages and machine codes, the complexities of machine codes are hided to the users, therefore, the new retargetable assembler system has higher retargetable level by converting the mapping from assembler languages and machine codes to assembler languages and CMDL, and implementationof it becomes easier. Based on the new mapping system structure, a retargetable assemblersystem is developed. It proved the whole system has good retargetability and implantability.【关键词】instruction set, symbol table, assembler, lexical analysis, retargetability
上传时间： 2013-10-10
上传用户：meiguiweishi
自动检测80C51串行通讯中的波特率:本文介绍一种在80C51 串行通讯应用中自动检测波特率的方法。按照经验，程序起动后所接收到的第1 个字符用于测量波特率。这种方法可以不用设定难于记忆的开关，还可以免去在有关应用中使用多种不同波特率的烦恼。人们可以设想：一种可靠地实现自动波特检测的方法是可能的，它无须严格限制可被确认的字符。问题是：在各种的条件下，如何可以在大量允许出现的字符中找出波特率定时间隔。显然，最快捷的方法是检测一个单独位时间（single bit time），以确定接收波特率应该是多少。可是，在RS-232 模式下，许多ASCII 字符并不能测量出一个单独位时间。对于大多数字符来说，只要波特率存在合理波动（这里的波特率是指标准波特率），从起始位到最后一位“可见”位的数据传输周期就会在一定范围内发生变化。此外，许多系统采用8 位数据、无奇偶校验的格式传输ASCII 字符。在这种格式里，普通ASCII 字节不会有MSB 设定，并且，UART总是先发送数据低位（LSB），后发送数据高位（MSB），我们总会看见数据的停止位。在下面的波特率检测程序中，先等待串行通讯输入管脚的起始信号（下降沿），然后起动定时器T0。在其后的串行数据的每一个上升沿，将定时器T0 的数值捕获并保存。当定时器T0溢出时，其最后一次捕获的数值即为从串行数据起始位到最后一个上升沿（我们假设是停止位）过程所持续的时间。
上传时间： 2014-08-22
上传用户：dajin
51单片机及其应用:1.1.1 电子计算机的问世及其经典结构1946年2月15日，第一台电子数字计算机问世，这标志着计算机时代的到来。（CALCULATOR）ENIAC（“埃尼阿克”）◆ENIAC是电子管计算机，时钟频率仅有100 KHz，但能在1秒钟的时间内完成5000次加法运算。◆与现代的计算机相比，有许多不足，但它的问世开创了计算机科学技术的新纪元，对人类的生产和生活方式产生了巨大的影响 。 匈牙利籍数学家冯·诺依曼在方案的设计上做出了重要的贡献。1946年6月，他又提出了“程序存储”和“二进制运算”的思想，进一步构建了计算机由运算器、控制器、存储器、输入设备和输出设备组成这一计算机的经典结构。（EDVAC-ELECTRONIC DISCRETE VARIABLE AUTOMATIC COMPUTER）二、微型计算机的应用形态 从应用形态上，微机可以分成三种：
标签： 51单片机
上传时间： 2013-12-20
上传用户：d815185728
