8.1 可编程并行接口芯片8255A 8.2 可编程定时器/计数器芯片8253/8254 8.3 串行通信及可编程串行接口芯片8251A 8.4 模/数（A/D）与数模（D/A）转换技术 及其接口 -8.1 programmable parallel interface chip 8255A8.2 programmable timer/counter chip 8253/82548.3 serial communications and programmable seri

实验采用七段码LED设计（数码管），显示直观；采用定时器中断，计时更准确；功能齐全，可随时启动、停止、清零，后者智能化程度更高。-Seven-Segment LED code using the experimental design (digital control), visual display using timer interrupt, a more accurate time functions, may at any time to start, stop, cleared,