Design And Research Of PCI Express Bridge Circuit Switching Core

The PCI Express bus is the third generation of high-performance IO bus released by PCISIG.Compared with the previous second-generation IO bus,there are two fundamental changes: First,the original parallel bus becomes a serial bus;The second is the use of a pointto-point interconnect structure.Compared to the PCI bus shared bus bandwidth,PCIe devices have more bandwidth.However,the number of bridges and buses is relatively large.The switch switch device then appeared in the topology of the PCI Express bus.This swap switch replaces the original bus in the PCI bus,allowing the PCI Express bus architecture to be easily extended.This paper is based on a non-blocking,low-latency,low-power 8-channel,8-port switch chip design project that I participated in during my internship.This article has carried on exhaustive analysis and research to the realization method of the switching core module(Switch Core)in this exchange switch chip,this realization way is based on the PCI Express bus key technology,carries on the data exchange through the transaction level data packet.The two functions of route control and data exchange between the exchange core module PCI Express ports were finally realized,and the design was completed.The crossover network was designed using a Butterfly BMIN architecture,and a data transfer message(DRM)method was adopted to replace the data payload transmission within the switching core module,which greatly accelerated the data transmission rate.At the same time,the module structure is simplified.And the use of hardware fixed arbitration and weighted poll arbitration to achieve the exchange of the core module port arbitration.Finally,in order to verify the correctness of the function of the designed switching core module,Synopsys' PCIe VIP was used to build a verification platform,which greatly improved the efficiency of verification.At the same time,the corresponding verification plan was developed,the function points were extracted,the test cases were written,and the functional simulation of the switching core module was carried out.For the two functions of the switching core module,we verified the exchange of data under various transmission scenarios for the data exchange function,verified the port arbitration function for the routing control function,and selected representative verification conditions and performed analysis and explanation.Finally,according to the verification results,it shows that the design of the switching core module can achieve routing control and data exchange between packets of PCI Express ports,achieving the target requirements.