采用外部中断INT0（用按键BUTTON模拟）中断，单片机P2口为输出口外接两位LED数码管。每申请一次中断（按下BUTTON），在中断处理程序中对数码管的显示数据作加1改变（实验中P2口外接的两位LED数码管采用7447硬件译码的方式以BCD码显示）。-The use of external interrupt INT0 (with simulated BUTTON button) interrupt, microcontroller P2 output port for an external LED digital tube 2. Interrupted every time the application (press the BUTTON), the interruption of the process of digital tube display data plus 1 change (P2 I experiment two external LED digital tube using 7447 hardware decoding approach to the BCD code display).