这个程序是在前面实验的基础上设计的一个综合程序。进入程序后演示led闪烁的各种效果。通过中断来接收PC的命令。在接收PC的命令时，使用Timer0来不保证命令的正确性、即保证命令是一个完整的语句。根据命令可以演示指定的led闪烁效果，写8255的任何一个端口，读8255任何一个端口的数据。如果发生外部中断，蜂鸣器连线正确，则蜂鸣器会一直响，直到目标板掉电或被复位。-This procedure is in front of the experimental design based on a comprehensive program. After entering the demonstration of the various effects of blinking led. PC through the disruption to receive orders. PC in order to receive, use Timer0 to the order does not guarantee the correctness, that is, to ensure that the order is a complete sentence. According to the order can be designated demonstration led blinking effect, to write a port of any 8255, 8255 any time the data port. If external interrupt, buzzer connected correctly, buzzer will sound until power-down or reset the target board.