STM32比较器

yjfself-230822

我用的是STM32L151CBT6，现在使用其中的比较器1遇到了问题，请大家帮助一下啊。
STM32L系列单片机比较器基本上雷同于STM32F系列比较器。用分析STM32F的思路就可以的。
问题如下:   使用的PA4 口输入到比较器1的正输入端。软件配置如下，用查询方式是可以正确检测输入端电压的，但是就是进不去比较器中断，请问是怎么回事啊。
void COMP_Config(void)
{
  NVIC_InitTypeDef        NVIC_InitStructure;
  //COMP_InitTypeDef        COMP_InitStructure;
  EXTI_InitTypeDef        EXTI_InitStructure;
  GPIO_InitTypeDef        GPIO_InitStructure;
 
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
  /* Configure PA4 in analog mode */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
 
  /* COMP Peripheral clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_COMP, ENABLE);
   
  COMP_Cmd(ENABLE); /* Enable the Comparator 1 */
  Delay(1);
  SYSCFG_RISwitchControlModeCmd(ENABLE);/* Enable the switch control mode */ 
  SYSCFG_RIIOSwitchConfig(RI_IOSwitch_VCOMP, ENABLE);/* Close the ADC analog switch VCOMP */  
  SYSCFG_RIIOSwitchConfig(RI_IOSwitch_CH18, ENABLE); /* Close the I/O analog switch number 4 */
    
  /* Configure and enable EXTI21 */
  EXTI_InitStructure.EXTI_Line = EXTI_Line21; 
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);
  /* Configure and enable COMP interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = COMP_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0f;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0f;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure); 
 
}

yjfself-230822

不好意思，刚才发的代码有问题，下面的是正确的。
还请各位多多帮忙，拜谢。
void COMP_Config(void)
{
  NVIC_InitTypeDef        NVIC_InitStructure;
  //COMP_InitTypeDef        COMP_InitStructure;
  EXTI_InitTypeDef        EXTI_InitStructure;
  GPIO_InitTypeDef        GPIO_InitStructure;
 
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
  /* Configure PA4 in analog mode */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;----------------------------------------更改
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);---------------------------------------------更改
  
  /* COMP Peripheral clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_COMP, ENABLE);
   
  COMP_Cmd(ENABLE); /* Enable the Comparator 1 */
  Delay(1);
  SYSCFG_RISwitchControlModeCmd(ENABLE);/* Enable the switch control mode */ 
  SYSCFG_RIIOSwitchConfig(RI_IOSwitch_VCOMP, ENABLE);/* Close the ADC analog switch VCOMP */  
  SYSCFG_RIIOSwitchConfig(RI_IOSwitch_CH4, ENABLE); /* Close the I/O analog switch number 4 */----------------------------------------更改
    
  /* Configure and enable EXTI21 */
  EXTI_InitStructure.EXTI_Line = EXTI_Line21; 
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);
  /* Configure and enable COMP interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = COMP_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0f;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0f;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);  
 
}