利用AT89C51单片机的定时，定时计数器T0秒，秒计数的时候，第二代，再加上1秒计数，计数到60秒，自动从0开始。单片机12MHz晶振频率-Using AT89C51 single-chip timing, timing counter T0 seconds, seconds count as a time when the second generation, plus 1 seconds count, count to 60 seconds, automatically　the beginning of 0. Crystal frequency chip 12MHZ