Design Of RS-422 Communication Unit Based On FPGA

Compare to RS-232, RS-422 ,which has the advantages of stronger anti-jamming ability, longer distance of transmission and higher transmission speed, has been extensive used in Distributed Control System (DCS) and local area network of industrial fields. With this in mind, this thesis developed the 422 communication unite and introduce the design method and application of the designing.This thesis originates from a practical engineering project, which belongs to the FPGA technology application in the electronic communication system category. The main task of this project is to test the parameter of an object in free flight by collecting and dealing the signals of the product. This thesis mainly introduces the designing of 422 communication unite based on FPGA, including the system overall design, the FPGA realization of the main controller, hardware design, bus connect protocol design, software design and so on.Firstly, we design the system overall structure, which is based on the analysis of the project background, project demand and the bus connect protocol. We set a transport protocol to standardize the data transmission. Secondly, according to the system design request, we select the main controller and peripheral component to build the system's platform and complete the system design. This designing includes the RS-232 Serial Communication Module(232SCM), RS-422 Electrical Level Convert Module(422ELCM), Main Control Module(MCM) and so on. Detailed hardware design and software design are performed in every module, and simulation is added to prove the function of the module.The unite is designed with modular programming mothed so that the unite is easy to extended and upgraded.The results of the system simulation show that FPGA-based 422 bus system is able to realize the data transmission of RS-422 serial bus very well.