Research And Implementation Of Data Link For Vehicle Bus Based On CPLD

since the 80's a big grows of electronic equipment have required more and more signals traveling from the sensors and actuators. Nowadays there is a lot of electronic equipment in a train: The traction control, the doors control, the air conditioners, the navigation systems, the passenger information services, and even TV and internet access, so it's require much higher levels to the train communication.The Multifunction Vehicle Bus (MVB), together with the Wire Train Bus (WTB) are part of the Train Communication Network (TCN), which is developed of the International Standard of IEC 61375-1. The MVB is a highly robust real-time field bus specifically designed for control systems built into railroad vehicles, and has become an international standard field bus in modern train communication network. It provides both the interconnection of programmable equipment amongst themselves and the interconnection of this equipment with its sensors and actors. Due to the fact that the MVB protocol is not specialized to specific transportation application, it is also very well suited in industrial application as a universal field bus where strict safety and reliability requirements are needed.This dissertalion firstly gives a brief introduction on the TCN, including the network structure, the Real-Time Protocol, data communication and the configurations. Then focus on the MVB, gives a research of the MVB in detail, especially the physical and link layers, and introduces the physical media, device types, bus structure and so on. Meanwhile, MVB is analyzed in theory, it is a deterministic and robust field bus more suitable for safety-sensitive systems which must operate in harsh and disturbed environments, for example inside railway vehicles of the train communication network.Two integrated design schemes of Multifunction Vehicle Bus Controller (MVBC) are presented in this thesis, and based on the laboratory condition we put forward a "MCU+CPLD/FPGA Architecture", to realize the function of MVBC. The main part of this scheme includes a microcontroller for the link and network layers, a CPLD for the implementation of Encoder/Decoder of the physical layer, to perform a slave node in a MVB communication. The emphasis of the design is the function realization in CPLD, the detailed logic circuit of CPLD and its VHDL program, and also the extended work for future are given.