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
伺服驱动器
上传时间： 2013-12-25
上传用户：偷心的海盗
特点 精确度0.1%满刻度±1位數 可直接量測交直流电压(AC/DC 20~265V)无需另接电源 精密濾波整流,均方根值校正 尺寸小(24x48x50mm),穩定性 分离式端子,配線容易 CE认证
上传时间： 2013-11-05
上传用户：gaome
SL811开发资料_包含源程序_电路图_芯片资料:SL811HS Embedded USB Host/Slave Controller.The SL811HS is an Embedded USB Host/Slave Controller capable of communicate with either full-speed or low-speed USB peripherals. The SL811HS can interface to devices such as microprocessors, microcontrollers, DSPs, or directly to a variety of buses such as ISA, PCMCIA, and others. The SL811HS USB Host Controller conforms to USB Specification 1.1.The SL811HS USB Host/Slave Controller incorporates USB Serial Interface functionality along with internal full-/low-speed transceivers.The SL811HS supports and operates in USB full-speed mode at 12 Mbps, or at low-speed 1.5-Mbps mode.The SL811HS data port and microprocessor interface provide an 8-bit data path I/O or DMA bidirectional, with interrupt support to allow easy interface to standard microprocessors or microcontrollers such as Motorola or Intel CPUs and many others. Internally,the SL811HS contains a 256-byte RAM data buffer which is used for control registers and data buffer.The available package types offered are a 28-pin PLCC (SL811HS) and a 48-pin TQFP package (SL811HST-AC). Both packages operate at 3.3 VDC. The I/O interface logic is 5V-tolerant.
上传时间： 2013-12-22
上传用户：a82531317
介绍了以PLC为控制单元，变频器为执行单元的控制系统及其在烟支输送储存系统中的应用，并给出了系统的组成、硬件的配置及具体的实现方法。关键词 : PLC 变频器输送储存系统 Ab str ac t;T hisp aperi ntroducest hec ontrols ystem whichc onsistso fP LCa ndf requencyc onvertera ndi ts application in the buffer conveyor for cigarettes. The system constitute, hardware disposal and realization method are also presented in detail.Keywords:PLC f requencyc onverter b ufferc onveyor
上传时间： 2013-10-22
上传用户：ouyang426
本“计算器”可以完成任意的通常借助手持计算器来完成的标准运算。“计算器”可用于基本的算术运算，比如加减运算等，以及C（清除）、AC（全部清零）、N（符号改变）、存储（M＋、M－、MR）、平方根和百分比运算。关于科学计算本“计算器”暂不支持。
上传时间： 2014-10-28
上传用户：BOBOniu
apache.org/commons/fileupload/下载。由于本人...关键步骤中的相关 操作为: 1) 在init(),用实例变量....1\db\db.prp idb.maxconn=2 access. url=jdbc:... URL,而且访问该数据库要使用JDBC-ODBC驱动程序。...
标签： fileupload commons maxconn apache
上传时间： 2013-12-18
上传用户：gxrui1991
Fourier-Mellin算法，更多细节请看下面的网址： http://www.ecs.soton.ac.uk/~aiw99r/fm_transform/
标签： Fourier-Mellin 算法
上传时间： 2014-01-05
上传用户：kristycreasy
1997年9月，NIST征集AES方案，以替代DES。 1999年8月，以下5个方案成为最终候选方案：MARS, RC6, Rijndael, Serpent, Twofish。 2000年10月，由比利时的Joan Daemen和Vincent Rijmen提出的算法最终胜出。（ Rijndael 读成Rain Doll。） http://www.esat.kuleuven.ac.be/~rijmen/rijndael/
标签： 1997
上传时间： 2014-01-19
上传用户：希酱大魔王
操作系统中的文件是通过文件目录项来管理的，为了管理和查找的方便，按层次把文件目录项组织起来，同一层上的目录构成该层上的目录，第一层为根目录，一下为各层子目录。 假设以一串字符代表一个文件，每个字符表示一个记录。 在建立上述目录结构的基础上，建立相应的管理系统并要求完成以下各项操作： 1． 一次建立各个文件 2． 查访两个用户的所有文件 3． 查访用户sun 是否有文件AB 4． 删除用户sun的文件AC,然后在分别查访两个用户的全部文件，检查是否已经删除文件AC 5． 撤销用户sun,并检查是否被删除 6． 删除用户sun的全部文件，然后在撤销sun用户，在查访用户sun, 检查其是否已被撤销。 在建立一个新用户及新用户的两个文件，然后查该两个用户的所有文件
上传时间： 2014-01-23
上传用户：xhz1993
