GD32F450死活进去不外部中断，到底出了什么问题

GD32F450进不去外部中断！！！用的C1口,可以读出C1口的高低电平没有问题，下面是程序，，出了什么问题呢
void exti1_init()
{
RCU_AHB1EN|=1<<2; //C1上拉输入
GPIO_CTL(GPIOC)&=~(1<<2);
GPIO_CTL(GPIOC)&=~(1<<3);
GPIO_PUD(GPIOC)|=1<<2;
GPIO_PUD(GPIOC)&=~(1<<3);

nvic_priority_group_set(NVIC_PRIGROUP_PRE2_SUB2);
nvic_irq_enable(EXTI1_IRQn,0,0);

 syscfg_exti_line_config(EXTI_SOURCE_GPIOC,EXTI_SOURCE_PIN1);	
exti_init(EXTI_1,EXTI_INTERRUPT,EXTI_TRIG_FALLING);
exti_interrupt_enable(EXTI_1);

}

void EXTI1_IRQHandler(void)
{

printf("\r\进入中断\r\n");

if(exti_flag_get(EXTI_1)!=0)
{
	exti_interrupt_flag_clear(EXTI_1);
}

}