Design And Implentation Signal Converter Module Based On FPGA

With the development of semiconductor process technology,monolithic integrated circuit integrity more and more high,greatly enhance the performance.Integration of industrial control,control precision and the complexity of the control is becoming more and more big.With the rapid development of computer network at the same time,and form a complete set of computer software and hardware also rely on each other,software system size is bigger and bigger.In order to meet the development of all walks of life,industry often communication bus is proposed to meet the needs of the industry itself,such as RS485 and CAN,an LVDS,as well as USB and so on.The bus personality,have their own characteristics.Both RS485 and CAN,an LVDS and USB communication protocol,although you CAN play to their respective characteristics in the specific field,but with diverse and interconnected bus equipment,the data exchange between different bus demand more and more strong.All kinds of industrial bus topology,electrical connections;Protocol processing,there is a large structure differences between application design.Between applications to the protocol processing,design,there exists a big difference in the structure of,even the most basic logic between bus are not compatible,let alone for data exchange.Industrial bus another characteristic is usually service for embedded systems,the stability of the bus is high,but relatively closed,debugging complex,bus erect when need to pay more time and money to debug the bus,until it can run on its own.In order to solve the above problems,many research institutes also has carried on the related research,design the function of many different protocol conversion equipment,to debug the underlying embedded bus system.Such as USB-CAN,PCI-CAN,USB-RS485 and PCIE-LVDS protocol conversion module and so on,although to a certain extent,solve the problem of single embedded bus debugging,but it cannot solve the problem of industrial bus extension.In order to solve the industrial bus extension ability,further between different bus equipment interconnection,for data sharing,a single protocol conversion function module is not enough.To solve the above problems,this paper proposes a based on the FPGA as the main controller,through the SJA1000 and PCA82C250 CAN bus interface,with CY7C68013 as USB bus controller to realize the USB interface from the machine,with SP485 EE as data parsing,RS485 bus driver with FPGA implementation RS485 interface,DS90LV032 as data parsing an LVDS receiver with FPGA to realize an LVDS interface.Designed a module to support multiple protocol data conversion.The protocol conversion module,respectively,to collect the data on the RS485 and an LVDS,through the FPGA to convert the string and parsing data after forwarding to the USB interface and uploaded to the computer,at the same time,the message of CAN bus CAN be independent to receive or send,through its then complete the traditional USB-CAN and USB-an LVDS-RS485 protocol conversion function.Based on this through the PC software to forward the data parsing and heavy package to a different interface,the realization of the indirect USB-CAN-LVDS-RS485 bus data transfer function.In this article,through further study of USB bus,CAN bus and RS485,the relation and difference between an LVDS,detailed elaborated the equipment hardware and software design,contains the power of the hardware design,to the bus interface design,match to the processor of each interface software.And leave on the bus extension interface,convenient for the expansion of the late.Finally,design the test platform to validate the design implementation of function,protocol conversion module can complete each bus data forwarding,can accomplish a certain number of packets analytical work.Through the test platform for the long time test data,ensure the stability of the whole design.Realized the purpose of data through the computer monitor the underlying bus,make up for the disadvantages of the current protocol conversion module single further expands the existing system.