51单片机内部中断，P1口接发光二极管，循环亮灯，外部键盘扫描中断，发生中断时，L3456同时亮灯，并持续五秒。-51 MCU internal interrupt, P1 mouth emitting diodes, circular lights, external keyboard scan interrupt, an interrupt occurs, the L3456 lights for five seconds.