基于CAN总线的单主时钟同步方法研究

Research of single master clock synchronization mechanism based on CAN bus

高精度和高可靠的时钟同步方法是CAN总线能够安全运行的关键,在分析主从、协商同步特点的基础上,提出了一种基于CAN总线的单主时钟协商同步方法,该方法仅需要一个时钟同步主节点即可实现总线的可靠运转,当从节点失效时利用CAN总线的时钟特性及时对即时偏差进行估计,使总线各节点依然能够正常工作,并引入时钟方差的概念更新主时钟同步优先级列表选择新的主节点。最后利用CANoe软件对该方法进行仿真,并利用51单片机、SJA1000T以及TJA1050构建硬件实验平台,结果表明该时钟同步机制能够防止单节点失效,可靠性高,具有更高的同步精度。

High precision and high reliability clock synchronization mechanism is the key to the safe operation of CAN bus. This paper aims at characteristic of master-slave clock synchronization and consultation selection clock synchronization, and proposes a single master clock syn- chronization mechanism based on CAN bus . This mechanism only needs one master synchronization node to achieve the reliable operation of the CAN bus. Estimating the value of instant deviation using clock characteristics of CAN bus can make each node of the bus work properly when slave clock node is invalid. And in order to select a new master synchronization node, the concept of clock variance is introduced to up- date master clock synchronization priority table. Finally it makes a simulation using CANoe and builds a hardware experimental platform using MCS-51 , SJA1000T and TJA1050. The results show that the mechanism can prevent single node failure and be more reliable.