从系统硬件设计和软件构成上，介绍一种以AT89C52单片机为核心,通过无线遥控方法实现对预设电话自动拨号报警的智能呼救系统。系统提供了患者在紧急情况下无法使用电话报警时的一种报警手段。由用户预设的多组电话号码作为语音报警对象,预录可长达20 s的语音信号来说明患者所处地点及病情，并通知患者家人。 Abstract: This paper introduces a intelligent alarming system which is realized by wireless remote control system.This system chiefly consists of AT89C51 the system can processor.User can input several groups of telephone number regarded as alarming objects,The system can record some information 20 seconds to tell the site of the patient.And notice the rokonok of the patient.
上传时间： 2013-11-19
上传用户：wd450412225
气压是气象监测中的一个重要参数，提出了一种气压数据采集模块设计方案，该模块采用数字气压传感器MS5534B、MSP430单片机MSP430F2272和带实时时钟（RTC）64 KB铁电存储器。通过低功耗软件设计方法以微安级整体平均功耗实现了气压数据的采集和存储，适合电池供电的连续高精度气压采集应用。给出了模块的软硬件设计以及MS5534B的性能指标和使用经验。 Abstract: Air pressure is an important parameter in weather monitor.This paper futs forward a new design scheme of low power-air pressure data acquisition module.The module uses a digital output barometer sensor MS5534B,MSP430 microcontroller MSP430F2272 and integrated RTC 64KB FRAM,precision air pressure measurement and storage chip.Another point of this module is low power consumption, so it is well suited for battery powered air pressure data acquisition applications. At the same time,the software and hardware deign of module is presented,And the speciaties and use notices of MS5534B are given.
上传时间： 2014-12-27
上传用户：drink！
介绍一种无极可调交流电子负载设计的新方法，由ATmega48单片机输出PWM波，通过上位机设定不同的占空比控制场效应管的通断时间，即改变流过场效应管的平均电流。根据电流的大小，可以等效为相应的负载，并将采集的电流值显示在上位机上。文中对该系统的软﹑硬件设计思路作了详细的分析，阐述了其设计原理。 Abstract: A new type electronic load is introduced.Due to ATmega48 microcomputer output PWM wave.The different duty is set ratio through PC to control FET turn-on time.We can equivalent homologous load according the current and display the current at PC.The hardware and software designing are analysed in detail. The principle is explained and the output is also given.
上传时间： 2013-11-23
上传用户：虫虫虫虫虫虫
为了解决磁放大器性能测试过程中，需要对其供给不同数值恒定电流的问题，设计了一种基于DAC7512和单片机的数控恒流源系统。该系统采用AT89C51作为主控器件，将计算机发送的电流控制字命令转换为D/A转换器控制字，通过模拟SPI通信接口，写D/A控制字到DAC7512，从而控制其输出相应数字电压值，经差动缩放电路、电压/电路变换电路和功率驱动电路，最后输出恒定电流。实验结果表明，恒流源输出电流调节范围为-45~+45 mA、精度为±0.1 mA，分辨率达0.024 4 mA，具有应用灵活，外围电路简单，可靠性高的特点。该数控直流恒流源也可为相关产品的测试系统研发提供参考。 Abstract: In order to solve the need to supply different values constant current for the magnetic amplifier in testing process， numerical control constant current source system was designed based on DAC7512 chip and microcontroller technology. The system used the AT89C51 as the main chip， which can convert the current control word from computer into to D/A control words. And the system wrote D/A control word into the DAC7512 chip to control the output voltage value by the SPI communication interface， which can output corresponding constant current figures by scaling circuit， the V/I converter and power drive circuit. Experimental results show that the current source output current adjustment range is -45~+45mA， accuracy is ± 0.1mA， and resolution ratio is 0.024 4mA
上传时间： 2014-12-27
上传用户：invtnewer
为降低成本和解决现有膜片钳放大器系统中PC机的干扰问题，研究了一种基于单片机的膜片钳放大器小系统。该系统采用ADI公司生产的ADuC841作为控制核心，并且配置相应的液晶显示模块LCM3202401。模拟电路部分采用高输入阻抗的AD8627实现微电流信号的采集，并由后级电路进行信号的放大和电阻电容的补偿。它具有硬件电路简单、体积小、使用方便的特点。既可以单独作为小系统实现采集和显示，也可以通过红外方式和PC机进行通讯，在PC机上进行信号的处理。 Abstract: In order to reduce cost and resolve the interferential problem with PC in existing patch clamp amplifiers, a small patch clamp amplifier system design based on microcontroller is studied. It adopts a new high performance microconverter ADuC841 by the ADI as the control core in the system, configuring a liquid crystal module LCM3202401. In the analog circuit, AD8627 with high input impedance is used to detect the low current，signal magnification, as well as resistance and capacitance compensation are accomplished by subsequent circuits. It has the advantage of simple hardware circuit design, small volume and convenient operation. It can either be used as an independent system to measure and show signal detected or transmit to PC by infrared ray.
上传时间： 2013-11-06
上传用户：yy_cn
在需要实时大量输入汉字的显示控制处理应用中，利用传统单片机实现显示控制的设计方法是较难实现的。带汉字字库的液晶模块的使用使得小容量ROM单片机的大量汉字信息输入与显示成为可能。提出了针对汉字字库编码的二级索引拼音输入检索方法,介绍了以ST7920作为控制器的带汉字字库的液晶显示模块的接口方法及汉字显示和控制原理，给出了通用计算机键盘在单片机中的串行接口，采用该技术可大大增强单片机的汉字输入功能。为小容量ROM单片机的大批量汉字信息处理提供了一种汉字输入解决方案。 Abstract: It is difficult to realize Chinese characters input method based on the embedded system by using the traditional design method of display control. It is possible to input and display Chinese characters based on the embedded system with the ROM of small content by using the LCD module with Chinese characters.Chinese characters input method of the quadric index recall in allusion to Chinese characters code is brought forward.The interface and the principle of Chinese characters display control based on the LCD module controlled with the ST7920 is introduced too.The serial interface of the computer keyboard in common use and the embedded system is given at the same time. It can enhance the embedded system function of Chinese characters input by using this technology, and provide a kind of Chinese characters input scheme for the embedded system with small capacity ROM.
上传时间： 2013-11-19
上传用户：jhksyghr
介绍了一种基于MSP430系列单片机和ADXL203加速度传感器的数字式倾角仪，它不仅可以实现水平度检测，而且可以测量00～3600范围内的任意倾角，分辨率可达O．1。。此外，由于该倾角仪输出为数字结果，因此它也可以与其他的数字设备结合起来，组合成一个功能更加强大的仪器。该数字倾角仪可广泛应用于建筑、机械、道路、桥梁、石油、煤矿和地质勘探等各种需要测量重力参考系下倾角的场合。关键词：MSP430F133单片机；力敏传感器；ADXL203加速度计；角度测量 Abstract：This paper presents a new style digital inclinometer which is developed on the basis of the MSP430F133 MCU and the ADXL203 dual axis aeeelerometer．This inclinometer not only can test levelness，but also can measure any angle between 0。and 360。with an accuracy of 0．1 O．In addition，its output is a digital result，which makes it possible to integrate itself with other digital devices to form a more functional unit．This inclinometer can be widely used in any construction site，oil field，coal-mine or geologic survey and SO on where it will provide the working people with convenience to measure any angles．Key words：MSP430F133 MCU；force sensor；ADXL203 accelerometer；angle measurement
上传时间： 2013-11-14
上传用户：lizhizheng88
The CAT823, CAT824, and CAT825 provide basic reset and monitoring functions for the electronic systems. Each device monitors the system voltage and maintains a reset output until that voltage reaches the device’s specified trip value and then maintains the reset output active condition until the device’s internal timer, after a minimum timer of 140ms; toallow the systems power supply to stabilize.
上传时间： 2014-11-18
上传用户：BOBOniu
The PCA9542A is a 1-of-2 bidirectional translating multiplexer, controlled via the I2C-bus.The SCL/SDA upstream pair fans out to two SCx/SDx downstream pairs, or channels.Only one SCx/SDx channel is selected at a time, determined by the contents of theprogrammable control register. Two interrupt inputs, INT0 and INT1, one for each of theSCx/SDx downstream pairs, are provided. One interrupt output, INT, which acts as anAND of the two interrupt inputs, is provided.
上传时间： 2013-12-07
上传用户：europa_lin
The PCA9549 provides eight bits of high speed TTL-compatible bus switching controlledby the I2C-bus. The low ON-state resistance of the switch allows connections to be madewith minimal propagation delay. Any individual A to B channel or combination of channelscan be selected via the I2C-bus, determined by the contents of the programmable Controlregister. When the I2C-bus bit is HIGH (logic 1), the switch is on and data can flow fromPort A to Port B, or vice versa. When the I2C-bus bit is LOW (logic 0), the switch is open,creating a high-impedance state between the two ports, which stops the data flow.An active LOW reset input (RESET) allows the PCA9549 to recover from a situationwhere the I2C-bus is stuck in a LOW state. Pulling the RESET pin LOW resets the I2C-busstate machine and causes all the bits to be open, as does the internal power-on resetfunction.
上传时间： 2014-11-22
上传用户：xcy122677
