STM32L073RZ的串口问题请教

ataudio 提问时间：2017-7-4 10:08 /

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使用STM32L073RZ开发的过程中，有两个疑问请网友帮忙解答一下。谢谢！

1）在STM32L073上使用4个串口，不包括LPUART。配置USART4和5时，HAL库中定义了USART4_5_IRQn作为中断向量。是否会导致中断乱入，或者不可控。有没有网友同时使用过？如果有深入理解的朋友，能不能对原理做下解释。
/*!< Interrupt Number Definition */
typedef enum
{
/******  Cortex-M0 Processor Exceptions Numbers ******************************************************/
  NonMaskableInt_IRQn       = -14, /*!< 2 Non Maskable Interrupt                               */
  HardFault_IRQn             = -13, /*!< 3 Cortex-M0+ Hard Fault Interrupt                      */
  SVC_IRQn                   = -5,    /*!< 11 Cortex-M0+ SV Call Interrupt                      */
  PendSV_IRQn                = -2,    /*!< 14 Cortex-M0+ Pend SV Interrupt                      */
  SysTick_IRQn             = -1,    /*!< 15 Cortex-M0+ System Tick Interrupt                   */

/******  STM32L-0 specific Interrupt Numbers *********************************************************/
  WWDG_IRQn                = 0,    /*!< Window WatchDog Interrupt                            */
  PVD_IRQn                   = 1,    /*!< PVD through EXTI Line detect Interrupt                */
  RTC_IRQn                   = 2,    /*!< RTC through EXTI Line Interrupt                      */
  FLASH_IRQn                = 3,    /*!< FLASH Interrupt                                        */
  RCC_CRS_IRQn             = 4,    /*!< RCC and CRS Interrupts                               */
  EXTI0_1_IRQn             = 5,    /*!< EXTI Line 0 and 1 Interrupts                         */
  EXTI2_3_IRQn             = 6,    /*!< EXTI Line 2 and 3 Interrupts                         */
  EXTI4_15_IRQn             = 7,    /*!< EXTI Line 4 to 15 Interrupts                         */
  TSC_IRQn                   = 8,    /*!< TSC Interrupt                                        */
  DMA1_Channel1_IRQn       = 9,    /*!< DMA1 Channel 1 Interrupt                               */
  DMA1_Channel2_3_IRQn       = 10,    /*!< DMA1 Channel 2 and Channel 3 Interrupts                */
  DMA1_Channel4_5_6_7_IRQn = 11,    /*!< DMA1 Channel 4, Channel 5, Channel 6 and Channel 7 Interrupts */
  ADC1_COMP_IRQn             = 12,    /*!< ADC1, COMP1 and COMP2 Interrupts                      */
  LPTIM1_IRQn                = 13,    /*!< LPTIM1 Interrupt                                     */
  USART4_5_IRQn             = 14,    /*!< USART4 and USART5 Interrupt                            */
  TIM2_IRQn                = 15,    /*!< TIM2 Interrupt                                        */
  TIM3_IRQn                = 16,    /*!< TIM3 Interrupt                                        */
  TIM6_DAC_IRQn             = 17,    /*!< TIM6 and DAC Interrupts                               */
  TIM7_IRQn                = 18,    /*!< TIM7 Interrupt                                        */
  TIM21_IRQn                = 20,    /*!< TIM21 Interrupt                                        */
  I2C3_IRQn                = 21,    /*!< I2C3 Interrupt                                        */
  TIM22_IRQn                = 22,    /*!< TIM22 Interrupt                                        */
  I2C1_IRQn                = 23,    /*!< I2C1 Interrupt                                        */
  I2C2_IRQn                = 24,    /*!< I2C2 Interrupt                                        */
  SPI1_IRQn                = 25,    /*!< SPI1 Interrupt                                        */
  SPI2_IRQn                = 26,    /*!< SPI2 Interrupt                                        */
  USART1_IRQn                = 27,    /*!< USART1 Interrupt                                     */
  USART2_IRQn                = 28,    /*!< USART2 Interrupt                                     */
  RNG_LPUART1_IRQn          = 29,    /*!< RNG and LPUART1 Interrupts                            */
  LCD_IRQn                   = 30,    /*!< LCD Interrupt                                        */
  USB_IRQn                   = 31,    /*!< USB global Interrupt                                  */
} IRQn_Type;

配置USART4的代码：
            ....
__HAL_RCC_USART4_CLK_ENABLE();

GPIO_InitStruct.Pin = GPIO_PIN_9|GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF6_USART4;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

/* Peripheral interrupt init */
HAL_NVIC_SetPriority(USART4_5_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(USART4_5_IRQn);

            .....

配置USART5的代码基本也类似。中断向量号IRQn也完全一样，这样USART4和5不会冲突吗？

2）配置USART2的GPIO的Alternate 时，有：
GPIO_InitStruct.Alternate = GPIO_AF0_USART2;
也有：
GPIO_InitStruct.Alternate = GPIO_AF4_USART2;
这里的AF0和AF4只见存在怎样的差异，对芯片实际有什么影响？

谢谢各位不吝指点！