Typical industrial and automotive applications requiremultiple high current, low voltage power supply solutionsto drive everything from disc drives to microprocessors.For many of these applications, particularly thosethat have size constraints, the LT3501® dual step-downconverter is an attractive solution because it’s compactand inexpensive compared to a 2-chip solution. The dualconverter accommodates a 3V to 25V input voltage rangeand is capable of supplying up to 3A per channel. Thecircuit in Figure 1 produces 3.3V and 1.8V.
上传时间： 2014-12-24
上传用户：372825274
This application note describes a reference system which illustrates how to build an embeddedPowerPC® system using the Xilinx 1-Gigabit Ethernet Media Access Controller processor core.This system has the PLB_Gemac configured to use Scatter/Gather Direct Memory Access andthe Serializer/Deserializer (SerDes) interface. This application note describes how to set up thespecific clocking structure required for the SerDes interface and the constraints to be added tothe UCF file. This reference system is complete with a standalone software application to testsome of the main features of this core, including access to registers, DMA capabilities, transmitand receive in loopback mode. This reference system is targeted for the ML300 evaluationboard.
上传时间： 2013-11-01
上传用户：truth12
15.2 已經加入了有關貫孔及銲點的Z軸延遲計算功能. 先開啟 Setup - constraints - Electrical constraint sets 下的 DRC 選項. 點選 Electrical constraints dialog box 下 Options 頁面 勾選 Z-Axis delay栏.
上传时间： 2013-11-12
上传用户：Late_Li
通用阵列逻辑GAL实现基本门电路的设计 一、实验目的 1.了解GAL22V10的结构及其应用； 2.掌握GAL器件的设计原则和一般格式； 3.学会使用VHDL语言进行可编程逻辑器件的逻辑设计； 4.掌握通用阵列逻辑GAL的编程、下载、验证功能的全部过程。 二、实验原理 1. 通用阵列逻辑GAL22V10 通用阵列逻辑GAL是由可编程的与阵列、固定（不可编程）的或阵列和输出逻辑宏单元（OLMC）三部分构成。GAL芯片必须借助GAL的开发软件和硬件，对其编程写入后，才能使GAL芯片具有预期的逻辑功能。GAL22V10有10个I/O口、12个输入口、10个寄存器单元，最高频率为超过100MHz。 ispGAL22V10器件就是把流行的GAL22V10与ISP技术结合起来，在功能和结构上与GAL22V10完全相同，并沿用了GAL22V10器件的标准28脚PLCC封装。ispGAl22V10的传输时延低于7.5ns，系统速度高达100MHz以上，因而非常适用于高速图形处理和高速总线管理。由于它每个输出单元平均能够容纳12个乘积项，最多的单元可达16个乘积项，因而更为适用大型状态机、状态控制及数据处理、通讯工程、测量仪器等领域。ispGAL22V10的功能框图及引脚图分别见图1-1和1-2所示。 另外，采用ispGAL22V10来实现诸如地址译码器之类的基本逻辑功能是非常容易的。为实现在系统编程，每片ispGAL22V10需要有四个在系统编程引脚，它们是串行数据输入(SDI)，方式选择(MODE)、串行输出(SDO)和串行时钟(SCLK)。这四个ISP控制信号巧妙地利用28脚PLCC封装GAL22V10的四个空脚，从而使得两种器件的引脚相互兼容。在系统编程电源为+5V，无需外接编程高压。每片ispGAL22V10可以保证一万次在系统编程。 ispGAL22V10的内部结构图如图1-3所示。 2.编译、下载源文件 用VHDL语言编写的源程序，是不能直接对芯片编程下载的，必须经过计算机软件对其进行编译，综合等最终形成PLD器件的熔断丝文件(通常叫做JEDEC文件，简称为JED文件)。通过相应的软件及编程电缆再将JED数据文件写入到GAL芯片，这样GAL芯片就具有用户所需要的逻辑功能。 3.工具软件ispLEVER简介 ispLEVER 是Lattice 公司新推出的一套EDA软件。设计输入可采用原理图、硬件描述语言、混合输入三种方式。能对所设计的数字电子系统进行功能仿真和时序仿真。编译器是此软件的核心，能进行逻辑优化，将逻辑映射到器件中去，自动完成布局与布线并生成编程所需要的熔丝图文件。软件中的constraints Editor工具允许经由一个图形用户接口选择I/O设置和引脚分配。软件包含Synolicity公司的“Synplify”综合工具和Lattice的ispVM器件编程工具，ispLEVER软件提供给开发者一个简单而有力的工具。
上传时间： 2013-11-17
上传用户：看到了没有
This document provides practical, common guidelines for incorporating PCI Express interconnect layouts onto Printed Circuit Boards (PCB) ranging from 4-layer desktop baseboard designs to 10- layer or more server baseboard designs. Guidelines and constraints in this document are intended for use on both baseboard and add-in card PCB designs. This includes interconnects between PCI Express devices located on the same baseboard (chip-to-chip routing) and interconnects between a PCI Express device located “down” on the baseboard and a device located “up” on an add-in card attached through a connector. This document is intended to cover all major components of the physical interconnect including design guidelines for the PCB traces, vias and AC coupling capacitors, as well as add-in card edge-finger and connector considerations. The intent of the guidelines and examples is to help ensure that good high-speed signal design practices are used and that the timing/jitter and loss/attenuation budgets can also be met from end-to-end across the PCI Express interconnect. However, while general physical guidelines and suggestions are given, they may not necessarily guarantee adequate performance of the interconnect for all layouts and implementations. Therefore, designers should consider modeling and simulation of the interconnect in order to ensure compliance to all applicable specifications. The document is composed of two main sections. The first section provides an overview of general topology and interconnect guidelines. The second section concentrates on physical layout constraints where bulleted items at the beginning of a topic highlight important constraints, while the narrative that follows offers additional insight.
上传时间： 2014-01-24
上传用户：s363994250
This a GA implementation using binary and real coded variables. Mixed variables can be used. constraints can also be handled. All constraints must be greater-than-equal-to type (g >= 0) and normalized (see the sample problem in prob1 in objective()).
标签： variables implementation Constra binary
上传时间： 2015-03-16
上传用户：qiao8960
内容如下： 1.The history of the computerized database 2.SQL Data Statements--those used to create, manipulate, and retrieve data stored in your database example statements include select, update, insert, and delete 3.SQL Schema Statements--those used to create database objects, such as tables, indexes, and constraints 4.How data sets can interact with queries 5.The importance of subqueries 6.Data conversion and manipulation via SQL s built-in functions 7.How conditional logic can be used in Data Statements
标签： computerized Statements database history
上传时间： 2015-04-25
上传用户：ardager
This project is created using the Keil ARM CA Compiler. The Logic Analyzer built into the simulator may be used to monitor and display any variable or peripheral I/O register. It is already configured to show the PWM output signal on PORT3.0 and PORT3.1 This ARM Example may be debugged using only the uVision Simulator and your PC--no additional hardware or evaluation boards are required. The Simulator provides cycle-accurate simulation of all on-chip peripherals of the ADuC7000 device series. You may create various input signals like digital pulses, sine waves, sawtooth waves, and square waves using signal functions which you write in C. Signal functions run in the background in the simulator within timing constraints you configure. In this example, several signal functions are defined in the included Startup_SIM.INI file.
标签： the Analyzer Compiler project
上传时间： 2013-12-19
上传用户：Yukiseop
Problem Statement You are given a string input. You are to find the longest substring of input such that the reversal of the substring is also a substring of input. In case of a tie, return the string that occurs earliest in input. Definition Class: ReverseSubstring Method: findReversed Parameters: string Returns: string Method signature: string findReversed(string input) (be sure your method is public) Notes The substring and its reversal may overlap partially or completely. The entire original string is itself a valid substring (see example 4). constraints input will contain between 1 and 50 characters, inclusive. Each character of input will be an uppercase letter ( A - Z ). Examples 0) "XBCDEFYWFEDCBZ" Returns: "BCDEF" We see that the reverse of BCDEF is FEDCB, which appears later in the string. 1)
上传时间： 2015-09-21
上传用户：sunjet
Embedded computer systems permeate all aspects of our daily lives. Alarm clocks, coffee makers, digital watches, cell phones, and automobiles are just a few of the devices that make use of embedded systems. The design and development of such systems is unique, because the design constraints are different for each system. Essential to the development of an embedded system is an understanding of the hardware and software used for development.
标签： Embedded computer permeate aspects
上传时间： 2013-12-15
上传用户：erkuizhang
