Fpga-based Multi-function Serial Communications Test Systems Designed

With the development of computer science and communication technology, more and more peripherals adopt USB interfaces which have high speed and excellent performance, while the RS232 interfaces on personal computers are phased out. In industrial applications, the mainstream communication interfaces of many devices used in industrial field are RS232, RS422, RS485,CAN and so on. The traditional interface conversion devices are designed by a variety of bus controllers, and they have high cost and large size.Most of these devices just achieve one to one conversion, and they can't process data.In view of the aforementioned background, this paper designs a kind of multi-serial communication system. It exchanges the USB with RS232, RS422, RS485 and CAN,then achieve the communication between the upper control computer and lower equipments.According to the system functional requirements, this paper adopts FPGA as the main chip to design the circuit. Some kinds of bus controller, such as UART and CAN controller, are realized in the FPGA through Verilog HDL. The user can set the baudrate through switch arrays, and add data processing section in the FPGA configuration process. The hardware system has lower cost, smaller size, and can process the data sent by lower equipments.In the part of software design, this study combines virtual instrument which has the feature of visual programming, and then design a LabVIEW test program. This test program completes the data transmission between the upper control computer and lower equipments, then saves and analyzes the data.At last, this study combines a servo control system with its communication protocol to verify the function of this multi-function serial communication test system.