这是一个用汇编语言编写实现的可编程并行接口实验，(1) 　　设置8255A的A口工作在方式1输出。

(2) 　　每按一次单脉冲按钮产生一个正脉冲使8255A产生一次中断请求。

(3) 　　设计中断服务程序，依次输出01H、02H、04H、08H、10H、20H、40H、80H，使L0~L7一次发光。

-It is written in assembly language implementation of a programmable parallel interface experiments, (1) A set 8255A' s work in the way of an output port. (2) a single pulse each time the button produces a positive pulse to generate an interrupt request 8255A. (3) Design interrupt service routine, followed by the output 01H, 02H, 04H, 08H, 10H, 20H, 40H, 80H, so that a light L0 ~ L7.