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.

8051总线控制8253输出PWM波，T0工作在模式2，T1工作在模式1。keilC程序+proteus仿真。可在示波器上管处啊pwm波的输出状况。-8253 8051 bus control output PWM wave, T0 in Mode 2, T1 work in mode 1. keilC program+ proteus simulation. Management Office in the oscilloscope wave ah pwm output condition.