| Nowadays, it is an inevitable trend that the new generation train is developing toward the aim of high-speed and automation. Train Communication Network (TCN) has become one of the key technologies which are applied to the control system of high-speed electrical train. There is no doubt that the devices conforming to the international standard of TCN will have a very promising prospect.According to the standard of IEC61375 the architecture of TCN is defined as a hierarchy which consists of two levels, they are Wired Train Bus (WTB) and Multifunction Vehicle Bus (MVB). As a recommendatory standard of IEC61375, the MVB is more and more applied in locomotives and vehicles. A device must connect to a special MVB network adaptor when it is communicating with MVB. However there are still some devices based on RS485 because of several reasons. So how to realize the data transmission between theses two kind of devices is becoming a problem needed to be solved as soon as possible.First, this thesis deeply analyses the MVB and R.S485 bus and the characteristics of their communication. Then it gives the implementation of the data transition between RS485 bus and MVB based on FPGA and AT89S52 platform. The FPGA is responsible for the communication with MVB while the MCU is responsible for the communication with RS485 bus. The transmission and control of data is realized through the connection of address bus and data bus between FPGA and MCU. The FPGA is designed as a MVB controller which consists of Manchester encoder, Manchester decoder, buffer, center control unit, internal memory, MCU interface and so on. This paper defines seven key words which can be used to access the MVB controller by MCU. User can program the MCU according to different protocol in RS485 bus to realize the data transmission between these two kinds of bus. Through the design of scheme and PCB, the network adaptor is implemented and is performed through the experiment. |
PDF Full Text Request