Design And Implementation Of Information Acquisition System Based On VME Bus In Loongson Platform

With the increasing number of information,it is more and and strict for the requirement of information acquisition system which processes data.The FPGA can collect and process data in real time,and can be cut according to the demand without changing the hardware circuit,it has the characterristics of flexibility.In order to meet high-speed and real-time data transmission,achieve the need of Localization acquisition system.This paper while bases on Loongson platform,adopts the VME bus architecture,and uses the FPGA hardware system designs and develops a set of high-speed information acquisition system that has good reliability and instantaneity.Under this requirement,this paper adopts the FPGA of Intel Stratix IV series as the acquisition chip.The host machine bases on Loongson 3A CPU and the hardware system which is built by PCIE bus architecture.Under the condition of high-speed data collection,this paper can improve the reliability of equipment by VME mechanical structure.The high-speed transmission system designed in this paper bases on PCIE bus,uses FPGA as the control chip,and use the VME mechanical structure is used to increase the stability on basis of high-speed transmission.Firstly,PCIE bus protocol is studied,and the TLP subcontract processing and allocation of configuration space of PCIE are emphasized.Then this paper presents the situation of the whole system's interconnection in the part of hardware system.It mainly designs and completes FPGA by On-Chip Memory,IP_Compiler for PCIE Express and Scatter-Gather DMA Controller construct the SOPC system.According to the connection of all modules in the system manually dispatch the base address of each module and allocate the key register.The development of software is based on kylin operating system that the kernel version is 3.12.11.According to the demand analysis designs the conrresponding device driver.Firstly,this paper designs the difficulties encountered in the driving development,such as scatter-gather DMA corresponding driver implementation include the design of data structure and DMA process.And then the design and description of the interrupt structure are griven.Finally,in the case of data loss in DMA transmission uses the circular queue to solve the problem,this mothod extends the data processing time and reduces the phenomenon of data deletion.In the driver realization portion,this paper adopts the implementation process of PCIE device driver and uses the character device to register for realizing the related operation of device.The key point is to explain the interruption process involving the DMA operation,and realize four FIFO parallel data transmission on the macro level.Then the API that is related to the equipment's operation is encapsulated as a dynamic link library.It is convenient for the user to call and ensure the security of the access device.Finally,it develops the QT test interface program to test the througuout of system.According to testing and analyzing data,the results are consistent with the theoretical throughput rate.