Abstract: Investment in smart meters and smart grid end equipment continues to grow worldwide as countriestry to make their electric delivery systems more efficient. However, as critical as the electric deliveryinfrastructure is, it is normally not secured and thus subject to attack. This article describes the concept oflife-cycle security—the idea that embedded equipment in the smart grid must have security designed into theentire life of the product, even back to the contract manufacturer. we also talk about how life-cycle securityapplies to embedded equipment in the smart grid. Potential threats are discussed, as are potential solutionsto mitigate the risks posed by those threats.
上传时间： 2014-12-24
上传用户：熊少锋
Each year Vishay releases thousands of new components that enable our customers to create new and superior end products. we recognize that offering unique component solutions helps improve the performance of next-generation devices, overcome technical barriers, and create new markets.
上传时间： 2013-12-14
上传用户：ming529
Occasionally, we are tasked with designing circuitry for aspecific purpose. The request may have customer originsor it may be an in-house requirement. Alternately, a circuitmay be developed because its possibility is simply tooattractive to ignore1. Over time, these circuits accumulate,encompassing a wide and useful body of proven capabilities.They also represent substantial effort. These considerationsmake publication an almost obligatory propositionand, as such, a group of circuits is presented here. This isnot the first time we have displayed such wares and, giventhe encouraging reader response, it will not be the last2.Eighteen circuits are included in this latest effort, roughlyarranged in the categories given in this publication’s title.They appear at the next paragraph.
上传时间： 2013-11-12
上传用户：012345
Providing power for the Pentium® microprocessor family isnot a trivial task by any means. In an effort to simplify thistask we have developed a new switching regulator controlcircuit and a new linear regulator to address the needs ofthese processors. Considerable time has been spent developingan optimized decoupling network. Here are severalcircuits using the new LTC®1266 synchronous buck regulatorcontrol chip and the LT®1584 linear regulator toprovide power for Pentium processors and Pentium VREprocessors. The Pentium processor has a supply requirementof 3.3V ±5%. The Pentium VRE processor requires3.500V ±100mV.
上传时间： 2013-11-01
上传用户：名爵少年
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
详细介绍工控软件组态王与单片机多机串口通讯的设计原理。分析组态王提供的直接与单片机串口通信方法的优点，给出系统基于RS-485总线传输的接口电路原理图。根据组态王提供的通讯协议和单片机多机串口通讯的原理，给出程序设计流程与思路。 Abstract: In this paper，the design principle of communication between multi-SCM and KingView by serial ports is described in detail.we analysis the advantage of method supplied by KingView,by which KingView can communicate with serial ports of SCM directly，and provide the system’s interface circuit based on the RS-485transmission line.we provide flow diagram of programming and thinking on the basis of communication protocol supplied by KingView and principle of communication among multi-SCM through serial ports.
上传时间： 2013-12-19
上传用户：tecman
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
针对当前安检力学试验机所能完成的试验种类单一、自动化程度低等问题，提出一种以ATmega128单片机为核心控制器的安检力学试验机的设计。详细阐述了该安检力学试验机各个组成部分的设计原理和方案，并且给出了各部分的软件设计思想和操作流程。经过大量测试试验表明：设计的安检力学试验机可以完成多达十余种的力学安检试验，完全符合相关国家标准，并且具有数据采集精度高、传输速度快、操作安全简便等特点，实现了安检设备的多功能化、数字化和自动化。 Abstract: Currently， many mechanical security testing machines have only one function. The degree of automation of them is low. To solve those problems， a new kind of mechanical security testing machine， using ATmega128 micro-controller as its core controller， has been advanced. It describes the components of the machine. The principles and the scheme in the designing processes are presented in detail， and the software architecture and the operation processes of each part are given. After having done many testing， we have reached the following conclusions: the mechanical security testing machine presented can do over ten mechanical security tests complying with related national standards. It has high data acquisition accuracy and high transmission speed. The operation of the machine is simple and safe. In general， this machine is a multi-functional， highly automatic， digitalized security testing device.
上传时间： 2013-11-05
上传用户：a67818601
MCS-51单片机数据存储器的扩展:3 数据存储器的扩展MCS-51单片机内部有128或256个字节的数据存储器，这些存储器通常被用作工作寄存器、堆栈、临时变量等等，一般已经够用，但是如果系统要存储大量的数据，比如数据采集系统，那么片内的数据存储器就不够用了，需要进行扩展。3．1 常用的数据存储器单片机中常用的数据存储器是静态RAM存储器（SRAM），图7是几种常用的数据存储器的引脚图，以62256为例介绍，其中：A0~A14：地址输入线；D0~D7：数据线； CE：选片信号输入线，低电平有效； OE：读选通信号输入线，低电平有效； we：写选通信号输入线，低电平有效；CE2：6264芯片的高有效选通端；VCC：工作电源，一般接+5V；GND：工作地.
上传时间： 2013-10-28
上传用户：jkhjkh1982
The 87LPC76X Microcontroller combines in a small package thebenefits of a high-performance microcontroller with on-boardhardware supporting the Inter-Integrated Circuit (I2C) bus interface.The 87LPC76X can be programmed both as an I2C bus master, aslave, or both. An overview of the I2C bus and description of the bussupport hardware in the 87LPC76X microcontrollers appears inapplication note AN464, Using the 87LPC76X Microcontroller as anI2C Bus Master. That application note includes a programmingexample, demonstrating a bus-master code. Here we show anexample of programming the microcontroller as an I2C slave.The code listing demonstrates communications routines for the87LPC76X as a slave on the I2C bus. It compliments the program inAN464 which demonstrates the 87LPC76X as an I2C bus master.One may demonstrate two 87LPC76X devices communicating witheach other on the I2C bus, using the AN464 code in one, and theprogram presented here in the other. The examples presented hereand in AN464 allow the 87LPC76X to be either a master or a slave,but not both. Switching between master and slave roles in amultimaster environment is described in application note AN435.The software for a slave on the bus is relatively simple, as theprocessor plays a relatively passive role. It does not initiate bustransfers on its own, but responds to a master initiating thecommunications. This is true whether the slave receives or transmitsdata—transmission takes place only as a response to a busmaster’s request. The slave does not have to worry about arbitrationor about devices which do not acknowledge their address. As theslave is not supposed to take control of the bus, we do not demandit to resolve bus exceptions or “hangups”. If the bus becomesinactive the processor simply withdraws, not interfering with themaster (or masters) on the bus which should (hopefully) try toresolve the situation.
上传时间： 2013-11-19
上传用户：shirleyYim
