想让串口1和串口3同时实现打印输出在PC上，为什么3不正常

   //USART ³õʼ»¯ÉèÖÃ

  USART_InitStructure.USART_BaudRate = bound;

  USART_InitStructure.USART_WordLength = USART_WordLength_8b;

  USART_InitStructure.USART_StopBits = USART_StopBits_1;

  USART_InitStructure.USART_Parity = USART_Parity_No;

  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

    //Usart1 NVIC ÅäÖÃ

  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0x01 ;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x00;  

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;   //IRQͨµÀʹÄÜ

  NVIC_Init(&NVIC_InitStructure); 

  USART_Init(USART1, &USART_InitStructure);

  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);//¿ªÆôÖжÏ

  USART_Cmd(USART1, ENABLE);    //ʹÄÜ´®¿Ú  

}

 //USART3配置

void uart3_init(u32 bound)

{

  GPIO_InitTypeDef GPIO_InitStructure;

  USART_InitTypeDef USART_InitStructure;

   NVIC_InitTypeDef NVIC_InitStructure;

  

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3|RCC_APB2Periph_GPIOB|RCC_APB2Periph_AFIO, ENABLE);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;//GPIO_Speed_50MHz;

  //GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;     

  GPIO_Init(GPIOB, &GPIO_InitStructure);

   

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;//GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; 

  GPIO_Init(GPIOB, &GPIO_InitStructure); 

  USART_InitStructure.USART_BaudRate = bound;

  USART_InitStructure.USART_WordLength = USART_WordLength_8b;

  USART_InitStructure.USART_StopBits = USART_StopBits_1;

  USART_InitStructure.USART_Parity = USART_Parity_No;

  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

  GPIO_PinRemapConfig(GPIO_Remap_USART2,ENABLE);

  NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0x01 ;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;  

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;   

  NVIC_Init(&NVIC_InitStructure); 

  USART_Init(USART3, &USART_InitStructure);

  USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);

  USART_Cmd(USART3, ENABLE);    

}