共阳、共阴数码管显示原理、定时器工作方式介绍、重点讲述工作方式2、中断概念及中断函数写法、外部中断试验、定时器中断应用-A total of Yang, a total of yin principle of digital tube display, timer, work presentations, focus on the work 2, interrupt concepts and interrupt function formulation, external interrupt test application of the timer interrupt