基于Cortex-M3的串口与CAN转换模块的设计与实现

Design and Implementation of Serial Port and CANConversion Interface Based on Cortex⁃M3

针对采用控制器局域网络(CAN:Controller Area Network)总线的自动操舵系统和采用串口通讯的航海导航设备之间通讯的不匹配问题,设计了一种基于Cortex-M3嵌入式平台的通信转换模块,实现了串口与CAN总线数据的双向转换功能。同时对传统CAN收发器CTM1050存在的信号稳定性不足、波特率精准度低等问题,提出并实现了一种硬件电路的替代方案,提高了数据通讯的时效性和稳定性。基于CAN2.0B扩展帧,设计了自动操舵系统内部CAN总线协议。该协议可根据报文信息优先级分配标识帧,保证了总线数据的有序传输。实验结果表明,该通讯模块功能使用正常且通讯效果良好,具有一定通用性,可在多种需要转换的设备系统上推广使用。

In order to solve the problem of communication mismatch between autopilot system using CAN(Controller Area Network)bus and navigation equipment using serial port communication,a communication conversion interface module based on Cortex⁃M3 is designed and the function of data conversion between serial port and CAN bus is realized.Aiming at the problems of poor signal stability and low baud rate accuracy of traditional CAN transceiver circuit CTM1050,an alternative hardware scheme is proposed and implemented to improve the timeliness and stability of data communication.Based on the CAN2.0B extension frame,the internal CAN bus protocol of the autopilot system is designed to ensure the scalability and stability of the bus.The protocol can assign identity frames according to the priority of message information to ensure the orderly transmission of bus data.The actual test results indicate that the communication module is normal and the communication effect is good.The communication module has a certain universality and can be used in a variety of equipment systems.