if (IC2Value != 0)
  {
    /* Duty cycle computation */
    DutyCycle = (TIM_GetCapture1(TIM2) * 100) / IC2Value;

    /* Frequency computation */
    Frequency = 72000000 / IC2Value;
  }
PWM输入捕获模式下计算占空比，为什么要乘以100“