| WTB (Wire Train Bus) is a part of TCN (Train Communication Network). TCN is the data communication network, which connects all equipments of whole train vehicles. The driver can control the whole train by TCN commands with the montor in driver's room, in order that the train can run normally. In 1999, the International Standard of TCN, IEC (International Electrotechnical Commission) 61375-1, was published, in which the TCN was defined as a bus of two-leveled hierachical structure, WTB and MVB( Multifunction Vehicle Bus). MVB is the internal bus in vehicle, and WTB is used to connect all MVBs in vehicles. So, each WTB node, including network adapter, plays the role of gateway.We have ever researched and developed WTB node, with PC104 Industrial Control Node Computer (ICNC) as node computer. WTB node network adapter is composed mainly by Altera FPGA EP1C6Q240C8. We proposed using embedded CPU to replace the PC104 ICNC. A project of WTB (Wire Train Bus) Network Control Node Computer (WNCNC) based on SOPC is researched and developed. The soft-core of embedded CPU, Nios II, and WTB network adapter are integrated in a single FPGA EP1C6Q240C8 chip, realizing the WNCNC functions. It significantly reduces the volume and weight, lowers hardware costs and increases the reliability of the system.To replace PC104 by Nios II, the PC104 bus must be replaced by the unique Avalon Bus of Nios II firstly. Secondly, the expansion of external RAM and FLASH should be sloved. Finally, the technology of the FPGA configuration has to be mastered.The project is firstly designed in the Altera development kits and successfully verified. We have researched and developed three prototypes and overcomed all difficulties. Many key technologies, such as Avalon Bus, the external RAM, FLASH and configuration, were sloved. Lastly, the WNCNC was successfully researched and developed. The experimental results show that SOPC based WNCNC achieved the desired specifications and requirements. |
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