Many CAD users dismiss schematic capture as a necessary evil in the process of creating\r\nPCB layout but we have always disputed this point of view. With PCB layout now offering\r\nautomation of both component placement and track Routing, getting the des
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.
The LTM8020, LTM8021, LTM8022 and LTM8023 μModule®regulators are complete easy-to-use encapsulated stepdownDC/DC regulators intended to take the pain and aggravationout of implementing a switching power supplyonto a system board. With a μModule regulator, you onlyneed an input cap, output cap and one or two resistorsto complete the design. As one might imagine, this highlevel of integration greatly simplifi es the task of printedcircuit board design, reducing the effort to four categories:component footprint generation, component placement,Routing the nets, and thermal vias.
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Xilinx UltraScale:The Next-Generation Architecture for Your Next-Generation Architecture
The Xilinx® UltraScale™ architecture delivers unprecedented levels of integration and capability with ASIC-class system- level performance for the most demanding applications.
The UltraScale architecture is the industr y's f irst application of leading-edge ASIC architectural enhancements in an All Programmable architecture that scales from 20 nm planar through 16 nm FinFET technologies and beyond, in addition to scaling from monolithic through 3D ICs. Through analytical co-optimization with the X ilinx V ivado® Design Suite, the UltraScale architecture provides massive Routing capacity while intelligently resolving typical bottlenecks in ways never before possible. This design synergy achieves greater than 90% utilization with no performance degradation.
Some of the UltraScale architecture breakthroughs include:
• Strategic placement (virtually anywhere on the die) of ASIC-like system clocks, reducing clock skew by up to 50%
• Latency-producing pipelining is virtually unnecessary in systems with massively parallel bus architecture, increasing system speed and capability
• Potential timing-closure problems and interconnect bottlenecks are eliminated, even in systems requiring 90% or more resource utilization
• 3D IC integration makes it possible to build larger devices one process generation ahead of the current industr y standard
• Greatly increased system performance, including multi-gigabit serial transceivers, I/O, and memor y bandwidth is available within even smaller system power budgets
• Greatly enhanced DSP and packet handling
The Xilinx UltraScale architecture opens up whole new dimensions for designers of ultra-high-capacity solutions.
在車載自組網(wǎng)中，路由協(xié)議很大程度上決定了整個網(wǎng)絡(luò)的性能。如何有效的利用車流信息提高傳輸質(zhì)量是改善路由性能的一個關(guān)鍵問題。本文基于速度-密度線性模型，提出了一種實(shí)時(shí)車流密度的路由協(xié)議RVDR（Real-time Vehicle Density Routing）。該協(xié)議通過與鄰居節(jié)點(diǎn)交換的速度信息，對相關(guān)道路車流密度進(jìn)行預(yù)測，并給出基于車流密度信息的路徑選擇方法。仿真結(jié)果表明，與現(xiàn)有協(xié)議相比，RVDR協(xié)議在實(shí)時(shí)性和高效性等性能方面得到改進(jìn)。
為滿足無線網(wǎng)絡(luò)技術(shù)具有低功耗、節(jié)點(diǎn)體積小、網(wǎng)絡(luò)容量大、網(wǎng)絡(luò)傳輸可靠等技術(shù)要求，設(shè)計(jì)了一種以MSP430單片機(jī)和CC2420射頻收發(fā)器組成的無線傳感節(jié)點(diǎn)。通過分析其節(jié)點(diǎn)組成，提出了ZigBee技術(shù)中的幾種網(wǎng)絡(luò)拓?fù)湫问剑⒀芯苛薢igBee路由算法。針對不同的傳輸要求形式選用不同的網(wǎng)絡(luò)拓?fù)湫问娇梢员M大可能地減少系統(tǒng)成本。同時(shí)針對不同網(wǎng)絡(luò)選用正確的ZigBee路由算法有效地減少了網(wǎng)絡(luò)能量消耗，提高了系統(tǒng)的可靠性。應(yīng)用試驗(yàn)表明，采用ZigBee方式通信可以提高傳輸速率且覆蓋范圍大，與傳統(tǒng)的有線通信方式相比可以節(jié)約40%左右的成本。
Abstract:
To improve the proposed technical requirements such as low-ower， small nodes， large capacity and reliable network transmission， wireless sensor nodes based on MSP430 MCU and CC2420 RF transceiver were designed. This paper provided network topology of ZigBee technology by analysing the component of the nodes and researched ZigBee Routing algorithm. Aiming at different requirements of transmission mode to choose the different network topologies form can most likely reduce the system cost. And aiming at different network to choose the correct ZigBee Routing algorithm can effectively reduced the network energy consumption and improved the reliability of the system. Results show that the communication which used ZigBee mode can improve the transmission rate， cover more area and reduce 40% cost compared with traditional wired communications mode.
