说明：  介绍美国DALLAS公司推出的具有涓细电流充电能力的低功耗实时时钟电路DS1302的结构、工作原理及其在实时显示时间中的应用。它可以对年、月、日、周日、时、分、秒进行计时，且具有闰年补偿等多种功能。给出DS1302在读写中的C51程序及流程图，以及在调试过程中的注意事项。
(Introduction of American DALLAS company with the introduction of the fine charging current capacity of low power real-time clock circuit DS1302 structure, working principle and application of real-time display of time.It can be years, months, days, Sunday, hours, minutes and seconds for time, and has multiple functions such as leap year compensation.DS1302 given in read and write in the C51 procedures and flow chart, as well as in the debugging process matters needing attention.)