这是一个简单的时钟综合实验，能够了解始终的工作原理，外部中断原理，单片机控制的多位数码管扫描显示电路，数码管动态显示的原理。-This is a simple clock experiments, always be able to understand the working principle, the principle of external interrupt, a number of microprocessor controlled digital tube to scan the