原理为：在单片机内部存储器设三个字节分别存放时钟的时、分、秒信息。利用定时器与软件结合实现1秒定时中断，每产生一次中断，存储器内相应的秒值加1；若秒值达到60，则将其清零，并将相应的分字节值加1；若分值达到60，则清零分字节，并将时字节值加1；若时值达到24，则将十字节清零。-The principle is: the single-chip internal memory set of three bytes of storage clock, minute and second information. Use a timer and software combination one second timer interrupt each generate an interrupt, the second value in memory plus 1 Seconds value of 60, it is clear, and the corresponding sub-byte value plus 1　if the score reach 60, the clear sub-bytes, and when the byte value 1　if the time value to reach 24will be 10 bytes cleared.