说明：  (1) 用单脉冲发生器的输出作为中断请求信号使8259A产生中断,进入中断后显示一个字符串。(2) 中断请求通过8259的IRQ2端输入，中断源可以是片外8253定时器输出的脉冲，并把8253的OUTO和总线槽IR02连接好。 (3) 编写程序,要求每次主机响应外部中断IRQ2时,显示字符串“THIS IS A 8259A INTERRUPT!”(或其它串)，中断十次后，程序退出。
((1) single-pulse generator output as an interrupt request signal generated interrupt 8259A, enter the show after the interruption of a string. (2) interrupt request through the 8259 end of IRQ2 input, interrupt source can be a 8253-chip timer output pulse, and the 8253 bus OUTO and IR02 connected trough. (3) preparation of procedures, requirements for each host in response to external interrupt IRQ2, the display string THIS IS A 8259A INTERRUPT! (Or other strings), interruption of ten times, withdraw from the program.)