现场总线设备链路层软件实时性分析与实现

摘要

In order to meet the real time requirement of a kind of field bus device, the real time requirement is analyzed and the link layer software is implemented.Link layer software consist of device driver, messages receive/transmit threads.Device driver controls the FPGA card and message queues are used to communicate between messages receive/transmit threads and user thread.To make time measure preciser, pulse signal at the entrance and exit of key modules are sent to oscilloscope.Employ oscilloscope to measure the runtime of key modules.The result shows the link layer software meets the real time requirement.%为满足一种现场总线设备的实时性,分析了其链路层软件的实时性需求,并实现了链路层软件.链路层软件由设备驱动程序和和消息接收发送线程组成,通过设备驱动程序实现对FPGA板卡的控制以及中断处理,使用消息队列实现消息收发线程与用户线程的通信.对影响实时性的关键时间段进行分析,为精确测量时间,在关键模块进出口使用发送脉冲到示波器,使用示波器对软件的关键模块运行时问进行测量.测量结果表明,能够满足设备的实时性需求.