初始化如下，读取TIM2->CNT就是没有计数，大神看看哪里有问题

void TIM2_init(void)
{
        RCC->APB1ENR |= 1<<0;//TIM2????
        GPIOA->MODER &=0XFFFFFFC0;//ê&#228;è&#235;&#196;￡ê&#189;
        GPIOA->PUPDR &=0XFFFFFFC0;//&#206;Té&#207;&#207;&#194;à-
        GPIOA->AFR[0] &= 0XFFFFFFF1;//

        TIM2->ARR = 5000;
        TIM2->SMCR = (1<<4)|(1<<5)|(1<<6)|(1<<14);//ía2&#191;′￥·￠ê&#228;è&#235;ETRF  ê1&#196;üía2&#191;ê±&#214;ó&#196;￡ê&#189;2
        TIM2->DIER |= (1<<0)|(1<<6);//&#212;êDí&#184;üD&#194;&#214;D&#182;&#207;  &#212;êDí′￥·￠&#214;D&#182;&#207;

        HAL_NVIC_SetPriority(TIM2_IRQn,3,3);
       
        TIM2->CNT =0;//&#188;&#198;êy&#198;÷&#199;&#229;á&#227;
        TIM2->CR1 |= 1<<0;//&#207;òé&#207;&#188;&#198;êy  ê1&#196;ü&#188;&#198;êy&#198;÷
}