1、 8个LED按流水方式显示，即LED1亮，其他LED灭；然后LED2亮，其他LED灭；以此类推。重复进行以上操作。
2、 当LED2、LED4、LED6、LED8亮时，蜂鸣器响；否则蜂鸣器不响。
3、 检测KEY1按键，如果KEY1按下，当前LED、蜂鸣器操作状态保持不变；否则，继续执行1、2控制策略。(1 , 8 LED are displayed by water flow, that is, LED1 is bright, other LED is destroyed; then LED2 is bright, other LED is eliminated, and so on. Repeat the above operation.
2, when LED2, LED4, LED6, LED8 bright, buzzer sound; otherwise buzzer does not sound.
3, detect the KEY1 button, if KEY1 press, the current LED, buzzer operating state remains unchanged; otherwise, continue to implement 1, 2 control strategy.)