用AT89C51单片机的定时，计数器T0产生一秒的 定时时间，作为秒计数时间，当一秒产生时，秒计数加1，秒计数到60时，自动从0开始。单片机晶振频率为12MHZ-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 to 60 seconds, automatically　the beginning of 0. MCU/crystal oscillator frequency is 12MHZ//1: with AT89C51 microcontroller timer/counter T0 timer seconds /, counts as a second time, when a second generation, second and 1// count, count to 60 seconds, automatically　the beginning of 0. Crystal frequency chip// 12MHZ