针对CAN总线通信方式的半双工和光纤传输全双工的转换问题,提出了一种基于等待接收和控制发送的机制。采用这种机制完成了光电转换电路的设计,在CPLD的控制下实现了半双工和全双工传输模式的转换,进而完成信号的光电转换。根据车辆总线信号电气特点以及光信号自身的特性,设计了车辆总线中数字信号在收发端的传输模式,完成光电转换的同时进行有效传输。搭建了整体的光电系统,通过测试系统能够传输CAN总线信号的最高速率为1 Mbps,并且长时间工作稳定,达到设计要求。
Propose a mechanism on the basis of the waiting to receive and controlling transmission to solve the problem of the conversion between the half-duplex of CAN-Bus communication and the full- duplex of fiber communication. Complete the design of the photoelectric conversion circles, realize the conversion between the half-duplex and full-duplex transition mode under the controlling of CPLD, and eventually accomplish the signal photoelectric conversion. According to the feathers of the vehicle bus signal and the characters of the optical signal of its own, designed a kind of transition mode of digital signal in the vehicle bus in order to get an effective transmission while the photoelectric conversion happened. Set up the whole optical and electrical system, and the highest transmission speed of the CAN-Bus is 1Mbps and run for a long time. It met the design requirements.