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。-DS1302 structure, working principle and its application in real-time display of time. It can be year, month, day, Sunday, hours, minutes, seconds for time, and has a leap year compensation and other functions. Gives the DS1302 in read and write procedures and flow chart of C51, and debugging process considerations.