请问为什么我这个仿真 定时器进入不了中断

窄门

f103的
void TIM5_Int_Init(u16 arr,u16 psc)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
        NVIC_InitTypeDef NVIC_InitStructure;

        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE); //ê±Öóê1Äü

        TIM_TimeBaseStructure.TIM_Period = arr; //éèÖÃÔúÏÂò»¸ö¸üDÂê¼t×°èë»î¶ˉμÄ×Ô¶ˉÖØ×°ÔؼÄ′æÆ÷ÖüÆúμÄÖμ         ¼Æêyμ½5000Îa500ms
        TIM_TimeBaseStructure.TIM_Prescaler =psc; //éèÖÃóÃà′×÷ÎaTIMxê±ÖóÆμÂê3yêyμÄÔ¤·ÖÆμÖμ  10KhzμļÆêyÆμÂê  
        TIM_TimeBaseStructure.TIM_ClockDivision = 0; //éèÖÃê±Öó·Ö¸î:TDTS = Tck_tim
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIMÏòéϼÆêyÄ￡ê½
        TIM_TimeBaseInit(TIM5, &TIM_TimeBaseStructure); //¸ù¾YTIM_TimeBaseInitStructÖDÖ¸¶¨μÄ2Îêy3õê¼»ˉTIMxμÄê±¼ä»ùêyμ￥λ
        TIM_ITConfig(TIM5,TIM_IT_Update,ENABLE);//ê1Äü»òÕßê§ÄüÖ¸¶¨μÄTIMÖD¶Ï
       
        NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn;  //TIM4ÖD¶Ï
        NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;  //ÏèÕ¼óÅÏ輶0¼¶
        NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;  //′óóÅÏ輶3¼¶
        NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQí¨μà±»ê1Äü
        NVIC_Init(&NVIC_InitStructure);  //¸ù¾YNVIC_InitStructÖDÖ¸¶¨μÄ2Îêy3õê¼»ˉíaéèNVIC¼Ä′æÆ÷

        TIM_Cmd(TIM5, ENABLE);  //ê1ÄüTIMxíaéè                                         
}