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以80X86为CPU的PC机已广泛应用于工业控制.工业环境中存在着大量的电磁干扰,这些干扰可能引起程序跑飞而死机.为了克服因程序跑飞而死机的故障,一般设置硬件看门狗定时器(WDT).硬件WDT有不足之处,它的时间常数需要合理选择,太短会使程序不能正常执行,太长则不能使系统及时恢复,另外硬件WDT会妨碍软件的开发调试.为了弥补硬件WDT的不足,设计了软件WDT,它能监视程序是否跑飞,跑飞时能自动复位系统.
80X86 as the CPU for the PC has been widely used in industrial control.Industrial environment there is a lot of electromagnetic interference, these disturbances may cause the program to fly and crash. In order to overcome the hang of the program due to run-time failure, the general set hardware gatekeeper The WDT has some shortcomings. The time constant of the WDT needs to be chosen reasonably. If it is too short, the program can not be executed normally. If the WDT is too long, the system can not be recovered timely. In addition, the WDT will hinder the development and debugging of the software. In order to make up for the shortage of the hardware WDT, the software WDT is designed, which can monitor whether the program runs and runs and automatically resets the system when running.