可编程并行接口8255A原理实验以及8253a中所用到的源程序.已经经过编译及上机实验。功能良好运转正常 -programmable parallel interface 8255A principle experiment and 8253a used by the source. Had already been Compiling and experiment on the plane. Good function in normal operation

8259原理 中断程序源代码.编译通过.运行良好