Scheme Of Can Bus Application Layer Protocol And Fault Tolerant Technology Research

Controller Area Network (CAN) is a serial bus system was introduced by Robert Bosch GmbH at the Society of Automotive Engineers (SAE) congress. in February 1986. The Controller Area Network (CAN) is a serial communications protocol which efficiently supports distributed realtime control with a very high level of security. Its domain of application ranges from high speed networks to low cost multiplex wiring. CAN is one of the most dominating bus protocols.CAN sepcification now has been set down the international standard bye ISO,and supported by many comapy.SAEJ1939 protocol is an application protocol introduced by SAE at first. It's widely used in automotive industry and other industrial equipument. Among all ripe high layer protocols, SAEJ1939 use extended identifier. The present analysis of SAEJ1939 mainly focus on protocol data unit, and there is few refermance to consult. In order to use J1939 protocol more effiecently, It is necessary to study J1939 protocol farther more and discuss realization of it.The work start with analysis of J1939 protocol specification.Firstly, make an intr-oduction about PDU (protocol data unit) which base on CAN2.0 PartB. PDU1 and PDU2 were introduced succeedingly.Dessertation in this part also discuss how to desig-n PDU. Senondly, connection establishment, data transmission and connection closure were introduced in transmission protocol part. Finally, net management protocol and procedure of address management was illustrated.On the basis of analysis of J1939 protocol data unit, This dissertation discuss methods of protocol realization such as protocol interface function, management protocol. In addition protocol software porting is discussed for different MCU. Finally, test of protocol software was made.And software stack works well.This dissertation also introduces a redundant CAN bus system without switch strategy in order to meet the requirements of high reliability. Dual redundant structure of the system is presented. Basic design considerations of J1939 protocol and processing method of redundant information are discussed. This system is reliable, pragmatic and easy to be implemented.