为了满足智能汽车对多路车载传感器的数据采集和数据可靠传输的需求,在CAN通信的标准帧中添加应用层协议,以“点名-应答”机制实现了一主多从的数据传输,并利用C8051F060内部的定时器实时监测总线上主节点下发点名指令和从节点应答的时间间隔,解决了传输链路在受到外部干扰后导致的数据包长短帧、节点延迟响应和故障节点异常离线等传输错误。采集模块采用单片机控制16选1的模拟开关ADG706和模/数转换器AD7667,实现对16路传感器数据的采集。最后经过多次测试验证和监测总线上的数据,CAN总线上传输速率达500 kb/s,可挂载32个从节点,并且每个节点可单独采集16路传感器数据,满足智能汽车对缓变信号的采集需求。

In order to meet the needs of smart cars for data collection and reliable data transmission of multi-channel on-board sensors,the application layer protocol is added to the standard frame of CAN communication,and the data transmission of one master and multiple slaves is realized by the mechanism of "call-and-reply",and use the timer inside the C8051F060 to monitor the time interval between the master node issuing the roll call command and the slave node replying on the bus from time to time,which solves the problem of the length of the data packet,the delay of the node response and the abnormal offline of the faulty node caused by the external interference of the transmission link.The acquisition module adopts the single-chip microcomputer to control the 16-to-1 analog switch ADG706 and the analog-to-digital converter AD7667 to realize the acquisition of 16-channel sensor data.Finally,after several tests to verify and monitor the data on the bus,the transmission rate on the CAN bus reaches 500 kb/s,32 slave nodes can be mounted,and each node can collect 16 channels of sensor data independently,which meets the requirements of smart cars for slowly changing signals.