基于51单片机的学习资料！里面有串口通信时钟ds12c887的程序资料和原理图（protel99）！程序清晰明了！注释的很清楚便于学习！-51 single-chip-based learning materials! There are serial communication clock ds12c887 program information and schematics (protel99)! Program clarity! Note the very clear easy to le