说明：  AT89C2051时钟程序定时器T0、T1溢出周期为50MS，T0为秒计数用， T1为调整时闪烁用， P3.7为调整按钮，P1口 为字符输出口，采用共阳显示管
(AT89C2051 Clock program timers T0, T1 overflow cycle 50MS, T0 for the second count of using, T1 flashes used for the adjustment, P3.7 to adjust the button, P1 port output ports for the characters, using a total of Yang Display Tube)