When two counters of the Intel8253 work at mode 1 and mode 2 respectively,the pulse sequence can be programmed with the change of the pulse width and pulse period.

• 该方法利用8253芯片的两个计时计、数通道分别工作在方式1和方式2,通过软件编程改变脉宽和脉间的时间值产生脉宽、脉间可变的脉冲序列。