利用8088/86外接8253可编程定时器/计数器，可以实现对外部事件进行计数。设置断点读回计数器的值。-8253 using 8088/86 external programmable timer/counter, external events can be counted on. Set a breakpoint counter value read-back.

微机原理数字钟 用8255 8253 8259等芯片 实现七段数码管 键盘控制-Principle of Microcomputer digital clock chip, etc. with 825,582,538,259 digital control keyboard control of Seven

8255的51单片机电子琴设计-8255 51 51 8255 microcontroller chip keyboard design keyboard design