Microchip 单片机的速度和复杂性已经到达足以要 求降低电源电压的程度,并正在向 5V 电源电压以 下转换。但问题是绝大多数接口电路仍然是为 5V 电源而设计的。这就意味着,作为设计人员,我们 现在面临着连接 3.3V 和 5V 系统的任务。此外, 这个任务不仅包括逻辑电平转换,同时还包括为 3.3V 系统供电、转换模拟信号使之跨越 3.3V/5V 的 障碍。 技巧和诀窍 DS41285A_CN 第 2 页 . 2006 Microchip Technology Inc. 本 《技巧和诀窍》提供了一些电源供电组件、数 字电平转换组件甚至模拟转换组件,以解决所面临 的挑战。全书对每种转换均给出了多种选择方案, 从单片 (All-in-One)接口器件到低成本的分立解 决方案都有涉及。简而言之,无论导致转换的原因 是复杂性、成本还是尺寸,设计人员处理 3.3V 挑 战可能需要的全部组件均在本文有所讨论。
上传时间: 2013-10-30
上传用户:wqxstar
Designing read/write device (RWD) units for industrial RF-Identification applications is strongly facilitated by the NXP Semiconductors HITAG Reader Chip HTRC110. All needed function blocks, like the antenna driver, modulator demodulator and antenna diagnosis unit, are integrated in the HTRC110. Therefore only a minimum number of additional passive components are required for a complete RWD. This Application Note describes how to design an industrial RF-Identification system with the HTRC110. The major focus is dimensioning of the antenna, all other external components including clock and power supply, as well as the demodulation principle and its implementatio
上传时间: 2013-10-22
上传用户:zhengjian
针对煤矿井下调度及紧急救援系统的需求,以DTMF编解码模块为核心,设计了具有自动拨号功能的新型电话系统。该系统利用MT8880对DTMF信号的编解码功能实现一键拨号和远程设置,通过检测振铃和忙音信号,完成自动摘机和挂机过程,配合AGC等外围电路达到话音清晰流畅的效果。 Abstract: To meet the demand for mine scheduling and emergency rescue system, with using DTMF signal codec as the core, a new telephone system was designed with automatic dialing function. In the system, the DTMF signal encoding and decoding function of MT8880 was used to achieve one-touch dialing and remote setting. The circuit detects the ringing and busy signal, and then completes automatic off-hook and hangup. With AGC(Automatic Gain Control) and other peripheral circuits, the voice was regulated to a clear and smooth effect.
上传时间: 2014-11-18
上传用户:ly1994
为了使音频信号分析仪小巧可靠,成本低廉,设计了以2片MSP430F1611单片机为核心的系统。该系统将音频信号送入八阶巴特沃兹低通滤波器,对信号进行限幅放大、衰减、电平位移、缓冲,并利用一单片机负责对前级处理后的模拟信号进行采样,将采集得到的音频信号进行4 096点基2的FFT计算,并对信号加窗函数提高分辨率,另一单片机负责对信号的分析及控制显示设备。此设计精确的测量了音频信号的功率谱、周期性、失真度指标,达到较高的频率分辨率,并能将测量结果通过红外遥控器显示在液晶屏上。 Abstract: o make the audio signal analyzer cheaper, smaller and more reliable, this system sends the audio signal to the eight-order butterworth filter, and then amplifies, attenuates, buffers it in a limiting range, transfers the voltage level of the signal before utilizing two MSP430F1611 MCU to realize the audio analysis. One is charged for sampling and dealing with the processed audio signal collected by the 4096 point radix-2 FFT calculation and imposes the window function to improve the frequency resolution. The other one controls the display and realizes the spectrum, periodicity, power distortion analysis in high resolution which is displayed in the LCD screen through the infrared remote control.
上传时间: 2013-12-11
上传用户:jasonheung
现有基于MAX7219芯片的数码管驱动电路只适用于小尺寸LED,为扩展其使用范围,在介绍动态显示芯片MAX7219功能的基础上,提出了一个基于该芯片的8位高亮度8英寸数码管驱动电路。电路保留了MAX7219芯片的功能强大、编程简单等优点,通过74LS273锁存器和ULN2803达林顿驱动器,实现了对任意大尺寸数码管提供较高电压和电流驱动的静态显示,并亮度可调。 Abstract: The existing display-driving circuit based on MAX7219 was only applicable to small-size LED. To expand its use, based on the function introduction of dynamic display chip MAX7219, a display-driving circuit for high-brightness 8-bit LED with the size of 8-inch was proposed. The advantages of MAX7219 were retained, such as powerful function and simple programming. Static display with adjustable brightness for large-size LED with higher voltage and current was achieved with the help of 74LS273 and ULN2803.
上传时间: 2013-10-23
上传用户:31633073
为提高电容测量精度,针对电容式传感器的工作原理设计了基于PIC16LF874单片机电容测量模块。简单阐述了电容测量电路的应用背景和国内外研究现状,介绍了美国Microchip公司PIC16LF874单片机的特性。电容式传感器输出的动态微弱电容信号通过PS021型电容数字转换器把模拟量数据转换成数字量数据,所测数据由PIC16LF874单片机应用程序进行处理、显示和保存。实验结果表明,固定电容标称值为10~20 pF 的测量值相对误差在1%以内,同时也可知被测电容容值越大,测量值和标称值相对误差越小。 Abstract: To improve the accuracy of capacitance measurement,aimed at the principle of work of mercury capacitance acceleration transducer,the design of micro capacitance measurement circuit is based on the key PIC16LF874 chip. Briefly discusses the application of the capacitance measuring circuit for the background and status of foreign researchers,focusing on the United States PIC16LF874 microcontroller features. Capacitive sensor outputed signal through the dynamics of weak PS021-chip capacitors (capacitancedigital converter) to convert analog data into digital data,the measured data from the PIC16LF874 microcontroller application process, display and preservation. Experimental results show that the fixed capacitor 10pF ~ 20pF nominal value of the measured value of relative error is within 1%,but also it canbe seen the value of the measured capacitance larger,measuring value and the nominal value of relative error smaller.
上传时间: 2013-10-29
上传用户:wojiaohs
提出一种基于凌阳单片机的步进电机加减速的控制方法。采用凌阳科技推出的16位结构工控单片机SPMC75F2413A为控制器,由Allegro公司生产的两相步进电机专用驱动器件SLA7042M构成步进电机的驱动电路,在传统的3段直线加减速控制算法基础上增加至7段S形曲线加减速过程,控制步进电机的启动和停止。实验结果表明,该控制方法克服了直线加减速中不连续、易造成系统冲击的问题,整个系统实现柔性控制,电机启动、停止连续性能提高30%。 Abstract: The method of controlled stepping motor is referred based on SPMC75F2413A MCU, which adopts the 16 knots SPMC75F2413A MCU as the controller. The special-purpose actuation chip SLA7042M of two stepping motor produced by Allegro Corporation constituted to actuation electric circuit. The purpose of increasing to seven section of S shape curve based on the traditional three sections of straight line is to control the start and stop process of stepping motor. The experimental results show that the control method solves easy to pull-out and overshot problems. The overall system realizes flexible control, and the performance of motor start or stop continuity is increased 30%
上传时间: 2013-12-08
上传用户:jiangfire
单片机作为一种微型计算机,其内部具有一定的存储单元(8031除外),但由于其内部存储单元及端口有限,很多情况下难以满足实际需求。为此介绍一种新的扩展方法,将数据线与地址线合并使用,通过软件控制的方法实现数据线与地址线功能的分时转换,数据线不仅用于传送数据信号,还可作为地址线、控制线,用于传送地址信号和控制信号,从而实现单片机与存储器件的有效连接。以单片机片外256KB数据存储空间的扩展为例,通过该扩展方法,仅用10个I/O端口便可实现,与传统的扩展方法相比,可节约8个I/O端口。 Abstract: As a micro-computer,the SCM internal memory has a certain units(except8031),but because of its internal storage units and the ports are limited,in many cases it can not meet the actual demand.So we introduced a new extension method,the data line and address lines combined through software-controlled approach to realize the time-conversion functions of data lines and address lines,so the data lines not only transmited data signals,but also served as address lines and control lines to transmit address signals and control signals,in order to achieve an effective connection of microcontroller and memory chips.Take microcontroller chip with256KB of data storage space expansion as example,through this extension method,with only10I/O ports it was achieved,compared with the traditional extension methods,this method saves8I/O ports.
上传时间: 2014-12-26
上传用户:adada
为提高太阳能的利用率,以ATmega8单片机为控制核心,设计了一套光电跟踪与视日运动轨迹跟踪互补控制的双轴太阳跟踪器。该跟踪器在晴天时,利用光敏电阻采集光强判断太阳位置,控制步进电机实现光电跟踪;在阴天时,采集时钟器件PCF8583的时间信息,计算当前太阳位置来实现视日运动轨迹跟踪。实验表明:该太阳跟踪器能在不同天气状况下对太阳进行较准确地跟踪,能量接收效率提高了30%,达到充分利用太阳能的目的。 Abstract: To improve the utilization rate of solar energy,a kind of solar tracking controller which effectively combined the sun angle tracking and photo electric tracking based on ATmega8is designed.In the sunny days,the solar tracking con-troller determines the sun's position by using photosensitive resistances to collect light intensity and control stepper motors to achieve photo electric tracking,n cloudy days,it collects clock chip PCF8583time information to calculate the current position of the sun and achieve the sun angle tracking.Experimental results show the solar tracking controller accurately tracks the sun in different weather conditions,improves received energy efficiency by30%and reaches the purpose of full use of solar energy.
上传时间: 2013-10-15
上传用户:urgdil
设计一种基于P89V51RD2的功率因数测量仪,采用光电隔离器和专用数码管驱动器。该测量仪是以增强型单片机P89V51RD2为核心,大大简化系统硬件设计。而软件部分采用模块化设计思想,采用中值滤波和小数补偿算法,实现功率因数的高精度测量。实验测试表明,该功率因数测量仪测量精度高,运行稳定可靠。 Abstract: A power-factor measurement instrument based on P89V51RD2is designed,which uses optical coupler and specific LED drive chip.The power factor measurement instrument uses P89V51RD2as a core of which greatly simplifies the system design.Furthermore,modularization software is developed in detail.The high precision power-factor measuring system is realized by the center value filter and fractional compensation algorithm.Experiments manifests that the power- factor measurement instrument is high precision,steady and reliable.
上传时间: 2014-12-27
上传用户:CHINA526