99秒马表设计。主要实现以下功能：（1)开始时，显示“00”，第1次按下SP1后就开始计时；（2)第2次按SP1后，计时停止；（3)第3次按SP1后，计时归零。实验原理图：-99 seconds stopwatch design. Achieve the following functions: (1) beginning to show " 00" , 1st time by pressing start after SP1 (2) 2 nd by SP1, the time

单片机语言实现LED点阵显示、滚动显示；99跑马表-Single Chip LED dot matrix display language, scroll 99 Happy Valley Table