用单脉冲发生器的输出脉冲作为中断源，每按一次按键产生一次中断申请，中断服务程序将在实验箱的显示屏显示一个字符“R”-Single-pulse generator output pulse as interrupt sources, each generated by a disruption of a key application for interrupt service routine to the display box in the experiment shows a character " R"