Design And Implementation Of Statistical Eye Diagram Simulation Tool Based On PCIe

With the development of electronic science and the continuous development of the electronic terminal market,the digital signal transmission rate of various electronic devices is continuously increasing,and the parallel bus can no longer meet the development speed of the processor.To effectively increase the transmission speed of the bus,there are generally two ways,one is to increase the frequency,and the other is to increase the processor bit width.If the frequency is increased blindly,the crosstalk between the parallel bus signals may increase,making it difficult to converge the timing;if the bit width is increased,the number of signal lines will increase,and other unnecessary problems will be caused.Based on the above problems,the high-speed serial bus began to take the stage of history,gradually replacing the parallel bus to occupy the mainstream position in the market,and the PCIe bus came into being.With the development of the PCIe bus,how to quickly and accurately evaluate the performance of the PCIe bus has become the primary concern of signal integrity engineers.Generally speaking,the eye diagram is one of the important ways for signal integrity engineers to evaluate the performance of high-speed systems.However,in many types of eye diagrams,the statistical domain eye diagram can contain more information.However,the traditional method of obtaining eye diagrams in the statistical domain consumes a lot of simulation time,such as using SPICE for pseudo-random binary sequence simulation,which makes it extremely time-consuming for engineers to perform signal integrity simulation and cannot meet the design requirements of signal integrity engineers.Therefore,it is extremely urgent to develop a signal integrity simulation tool that can quickly and accurately obtain eye diagrams in the statistical domain for the PCIe bus.Based on the above industry background and the current needs of the industry,this thesis develops a set of statistical domain eye diagram simulation tools for PCIe bus based on C++code.The input parameters of this tool are the S-parameter file of the target channel and crosstalk,and the output result is the statistical domain eye diagram of the target channel.In addition,a series of signal integrity simulation parameters such as equalization,jitter,and noise are added to the tool.Among them,equalization is mainly divided into forward feedback equalization(FFE),continuous-time linear equalization(CTLE)and decision feedback equalization(DFE),and all three types of equalization support fixed coefficient and adaptive equalization;Jitter is divided into random jitter,dual-Dirac jitter,and uniformly distributed jitter;noise is divided into random voltage noise and uniformly distributed voltage noise.At the same time,it supports the multi-parameter sweep simulation(Sweep)function,that is,the user inputs multiple sets of different simulation parameters,and the tool can simulate all the results at one time.This thesis also develops a simple and easy-tounderstand user interface based on Qt,which makes it easier for engineers to use.At the same time,it also uses multi-threading technology to separate the interface part from the algorithm department.The advantage of multithreading is that the software can provide error reporting functions and avoid crashes and jams when simulation errors occur.This thesis describes in detail the principle of the algorithm part of the tool,the design of the code part and the detailed use of the tool,and verifies the accuracy,practicability and feasibility of the statistical domain eye diagram simulated by the tool,which is signal integrity Engineers provide convenience when designing PCIe high-speed systems,and have strong guiding significance for the design of future signal integrity EDA tools.