shengchanliushuixian

代码说明：

   利用可编程计数/定时器8253设计一个应用于生产流水线的自动计数系统。通过具体阐述8253的工作原理，系统的软、硬件设计原理以实现系统所需定时、计数、中断等功能，并驱动扬声器发出所需频率的声音。(Using the programmable counts/timer 8253 design a applied to production line of automatic counting systems. Through the concrete 8253 working principle, hardware and software of the system design principle to achieve system, such as timing, counting, and drive a loudspeaker functions required sounds.)