Research On Adapter Technology For Multi-bus Interfaces Based On FPGA

Because of the heavy weight, low transmission speed and expensive cost, traditional aviation data bus has been unable to meet the needs of new aircrafts.Therefore,ARINC664 standard proposed a new type of aviation data network standard, that is, Avionics Full Duplex Switched Ethernet(AFDX).However, due to current aircrafts still preserve a lot of airborne equipment using RS-422 and CAN bus protocol, how to make these equipment access AFDX backbone network to complete the interaction with the AFDX is a question worth researching.This paper designed a multi-bus adapter unit using FPGA based on the research of RS-422, CAN and AFDX bus protocol. The multi-bus adapter is mainly used to solve the problem of the interaction between RS-422, CAN and AFDX bus protocol, and complete the bidirectional conversion between these protocols. In the hardware design of the multi bus adapter unit, this paper selected Spartan 6 designed by Xilinx as the core chip, LXT973, CTM8251 LAT and MAX3283/MAX3295 as the AFDX, CAN and RS-422 physical layer chip to complete information exchange task between the three and core chip FPGA. At the same time, the hardware language was used to complete the design of IP core of CAN controller, which provides the basic conditions for the realization of the exchange between CAN and AFDX bus. In the software design, this paper made FPGA equipped with MicroBlaze processor, selected AXI bus as an external device interface bus and used the Xilkernel operating system as the software processing platform. This paper described the software system design, hardware driver and the main program of the signal exchange for the multi-bus adapter unit in detail.The design of the multi-bus adapter unit through the combination of hardware and software to realized the AFDX bus protocol from the application layer to the physical layer and completed the signal exchange between AFDX/RS-422 and AFDX/CAN bus protocol. Finally, the function test of the multi-bus adapter unit is completed by experiments, which proves the feasibility of the design.