High Speed Signal Integrity Analysis And Design Of Hardware System Based On Enterprise Router

Routers, as an important part in the internet system, are the devices for LAN andwan connection. They select the most appropriate path according to thereal situation ofthe channel and are widely used in all walks of our life..Forwarding abilities of a router,largely determine the performance of the entire network.Forwarding capabilities of router are determined by network throughput. Highperformance processor chip and advanced routing algorithm are the bases for routerperformance.With the rapid development of semiconductor industry under the Moore’slaw, the chip rate goes higher and higher.The enterprise-class router chip introduced inthe paper is a dual-core communication processor from Freescale PowerQUICC productline. The real time clock reaches125MHz, which then brings all sorts of challenges tohigh-speed high-density circuit design. Signal integrity problems are the mostprominent problems in high speed digital system design. Crosstalk, overshoot andringing which appeared simple questions may cause time-series of discontent, and evenlead to system instability, making system down.In this paper, based on the signalintegrity analysis method of the high-speedrouter hardware system design, CadenceAllegro SPB16was used for single board layout and wiring in simulation. Constraintrules were also set to ensure the signal quality and stability of the veneer.This paper firstly introduces the P1025microprocessor and CPLD based onfreescale hardware platform composed of high-speed router. Then system design basedon the simulation results and the test results of reflection and ringing, timing and signalintegrity problems, and putting forward the solutions. The main contents are as follows:①According to the demand analysis and design the router architecture, the designmethod based on signal integrity analysis of hardware circuit design work.②Analysis of signal integrity problems of router hardware system, and the keysignal level front-end circuit simulation design.③Introduce the basic theory of transmission line, the integrity of the definition ofhigh speed signal and its basic problems, analysis of crosstalk, noise, and the principleof timing problem. Establish equivalent model, starting from the principle analysis ofthe topology of the clock, optimize the clock go line, design matching signal distortioncaused by resistance to avoid impedance discontinuity.④In view of the higher rate of DDR3memory principle, design circuit and a new test method based on signal integrity, ensure DDR3under the specialty experiment ofhigh speed high temperature can normal work.Finally through the professional experiment test and the feedback of the result partof the revision,we revise the high-speed router system schematic diagram design, makethe system to optimize the signal integrity, the system also can work stable under harshconditions. The entire design process adopted a new design method based on signalintegrity, and starting from the principle diagram in detail design phase signal testingmethod and strategy, greatly save the design cycle, and guarantee the quality of veneer.