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.
標(biāo)簽： 智能電表 智能電網(wǎng)
上傳時間： 2014-12-24
上傳用戶：熊少鋒
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.
上傳時間： 2013-12-14
上傳用戶：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.
標(biāo)簽： 信號源 調(diào)節(jié)器 電源 電路分析
上傳時間： 2013-11-12
上傳用戶：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.
上傳時間： 2013-11-01
上傳用戶：名爵少年
單片機(jī)作為一種微型計算機(jī)，其內(nèi)部具有一定的存儲單元（8031除外），但由于其內(nèi)部存儲單元及端口有限，很多情況下難以滿足實(shí)際需求。為此介紹一種新的擴(kuò)展方法，將數(shù)據(jù)線與地址線合并使用，通過軟件控制的方法實(shí)現(xiàn)數(shù)據(jù)線與地址線功能的分時轉(zhuǎn)換，數(shù)據(jù)線不僅用于傳送數(shù)據(jù)信號，還可作為地址線、控制線，用于傳送地址信號和控制信號，從而實(shí)現(xiàn)單片機(jī)與存儲器件的有效連接。以單片機(jī)片外256KB數(shù)據(jù)存儲空間的擴(kuò)展為例，通過該擴(kuò)展方法，僅用10個I/O端口便可實(shí)現(xiàn)，與傳統(tǒng)的擴(kuò)展方法相比，可節(jié)約8個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.
標(biāo)簽： 單片機(jī) P0口 數(shù)據(jù)存儲器 擴(kuò)展
上傳時間： 2014-12-26
上傳用戶：adada
詳細(xì)介紹工控軟件組態(tài)王與單片機(jī)多機(jī)串口通訊的設(shè)計原理。分析組態(tài)王提供的直接與單片機(jī)串口通信方法的優(yōu)點(diǎn)，給出系統(tǒng)基于RS-485總線傳輸?shù)慕涌陔娐吩韴D。根據(jù)組態(tài)王提供的通訊協(xié)議和單片機(jī)多機(jī)串口通訊的原理，給出程序設(shè)計流程與思路。 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.
標(biāo)簽： 工控軟件 單片機(jī) 串口通訊 多機(jī)
上傳時間： 2013-12-19
上傳用戶：tecman
介紹一種無極可調(diào)交流電子負(fù)載設(shè)計的新方法，由ATmega48單片機(jī)輸出PWM波，通過上位機(jī)設(shè)定不同的占空比控制場效應(yīng)管的通斷時間，即改變流過場效應(yīng)管的平均電流。根據(jù)電流的大小，可以等效為相應(yīng)的負(fù)載，并將采集的電流值顯示在上位機(jī)上。文中對該系統(tǒng)的軟﹑硬件設(shè)計思路作了詳細(xì)的分析，闡述了其設(shè)計原理。 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.
標(biāo)簽： ATmega 48 單片機(jī) 交流電子
上傳時間： 2013-11-23
上傳用戶：蟲蟲蟲蟲蟲蟲
針對當(dāng)前安檢力學(xué)試驗機(jī)所能完成的試驗種類單一、自動化程度低等問題，提出一種以ATmega128單片機(jī)為核心控制器的安檢力學(xué)試驗機(jī)的設(shè)計。詳細(xì)闡述了該安檢力學(xué)試驗機(jī)各個組成部分的設(shè)計原理和方案，并且給出了各部分的軟件設(shè)計思想和操作流程。經(jīng)過大量測試試驗表明：設(shè)計的安檢力學(xué)試驗機(jī)可以完成多達(dá)十余種的力學(xué)安檢試驗，完全符合相關(guān)國家標(biāo)準(zhǔn)，并且具有數(shù)據(jù)采集精度高、傳輸速度快、操作安全簡便等特點(diǎn)，實(shí)現(xiàn)了安檢設(shè)備的多功能化、數(shù)字化和自動化。 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.
標(biāo)簽： ATmega 128 安檢 試驗機(jī)
上傳時間： 2013-11-05
上傳用戶：a67818601
MCS-51單片機(jī)數(shù)據(jù)存儲器的擴(kuò)展:3 數(shù)據(jù)存儲器的擴(kuò)展MCS-51單片機(jī)內(nèi)部有128或256個字節(jié)的數(shù)據(jù)存儲器，這些存儲器通常被用作工作寄存器、堆棧、臨時變量等等，一般已經(jīng)夠用，但是如果系統(tǒng)要存儲大量的數(shù)據(jù)，比如數(shù)據(jù)采集系統(tǒng)，那么片內(nèi)的數(shù)據(jù)存儲器就不夠用了，需要進(jìn)行擴(kuò)展。3．1 常用的數(shù)據(jù)存儲器單片機(jī)中常用的數(shù)據(jù)存儲器是靜態(tài)RAM存儲器（SRAM），圖7是幾種常用的數(shù)據(jù)存儲器的引腳圖，以62256為例介紹，其中：A0~A14：地址輸入線；D0~D7：數(shù)據(jù)線； CE：選片信號輸入線，低電平有效； OE：讀選通信號輸入線，低電平有效； WE：寫選通信號輸入線，低電平有效；CE2：6264芯片的高有效選通端；VCC：工作電源，一般接+5V；GND：工作地.
標(biāo)簽： MCS 51 單片機(jī) 數(shù)據(jù)存儲器
上傳時間： 2013-10-28
上傳用戶：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.
標(biāo)簽： routines slave I2C 87L
上傳時間： 2013-11-19
上傳用戶：shirleyYim
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