利用单片机的内部定时器溢出产生中断来实现定时，

把单片机内部的定时/计数器0作为定时器，实现2.5ms定时。外部待测脉冲从单片机的TI（第15引脚）输入，以定时/计数器1作为计数器，利用中断方式来达到间接测量的目的。最后采用四位数码管显示-The use of MCU internal timer overflow interrupt to achieve timing, the MCU internal timer/counter 0 as a timer, the timing to achieve 2.5ms. External test pulses　the microcontroller TI (15 pin) input to timer/counter 1 as a counter, interrupt use to achieve the purpose of indirect measurement. Finally, four digital display