本人遇到如下问题，按照下面的库函数调用，单独打开一个串口，完全正常，但是同时打开USART1 USART2时，USART2不工作，不知道何故，请高人指点一二//-------------------------------------------初始化部分----------------------------------------------------------------------------------------------------------------------------------------------------------------------
void GPIO_System_Initrial()
{  
GPIO_InitTypeDef GPIO_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD|RCC_APB2Periph_GPIOA,ENABLE);        //串口部分初始化和LED显示部分的初始化

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;//推挽输出
GPIO_Init(GPIOD, &GPIO_InitStructure);              //LED全部输出状态。

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//复用推挽输出，针对TXD1 TXD2设置
GPIO_Init(GPIOA, &GPIO_InitStructure);   

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_3;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//，针对TXD1 TXD2设置
GPIO_Init(GPIOA, &GPIO_InitStructure);   
}
//-------串口的初始化过程------------------------
void Uart_System_Initrial()
{
  USART_InitTypeDef USART_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);

  USART_InitStructure.USART_BaudRate = 9600;//波特率=115200
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;//数据位字长=8
  USART_InitStructure.USART_StopBits = USART_StopBits_1;//停止位=1
  USART_InitStructure.USART_Parity = USART_Parity_No;//无奇偶校验位
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; //无需RTS CTS硬件控制
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //串口接收发送同时有效
  USART_Init(USART1, &USART_InitStructure); //配置串口1，若配置USART2，需重新写一遍上述
  
  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
  USART_ITConfig(USART1, USART_IT_TXE, ENABLE);

  USART_ClearFlag(USART1, USART_FLAG_RXNE);
  USART_ClearFlag(USART1, USART_FLAG_TXE);

  USART_InitStructure.USART_BaudRate = 9600;//波特率=115200
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;//数据位字长=8
  USART_InitStructure.USART_StopBits = USART_StopBits_1;//停止位=1
  USART_InitStructure.USART_Parity = USART_Parity_No;//无奇偶校验位
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; //无需RTS CTS硬件控制
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //串口接收发送同时有效
  USART_Init(USART2, &USART_InitStructure); //配置串口1，若配置USART2，需重新写一遍上述

  USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
  USART_ITConfig(USART2, USART_IT_TXE, ENABLE);

  USART_ClearFlag(USART2, USART_FLAG_RXNE);
  USART_ClearFlag(USART2, USART_FLAG_TXE);

  USART_Cmd(USART2, ENABLE);
  USART_Cmd(USART1, ENABLE);

}
//---------中断模块的初始化配置过程--------------
void NVIC_System_Initrial()
{
  NVIC_InitTypeDef NVIC_InitStructure;

  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);  

  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;             //定义
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;   //先占优先级
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;          //从占优先级
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;             //使能定义的中断是否开启。
  NVIC_Init(&NVIC_InitStructure);
   
  NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;             //定义
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;   //先占优先级
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;          //从占优先级
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;             //使能定义的中断是否开启。
  NVIC_Init(&NVIC_InitStructure);

}
//------------------------------------------------结束--------------------------------------------------

//---------------------------中断部分---------------------------------------------------
void USART1_IRQHandler(void)
{
if(USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == SET)
  {
    USART_ClearFlag(USART1,USART_FLAG_RXNE);
    USART_SendData(USART1,USART_ReceiveData(USART1));
        while(USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET);
    USART_ClearFlag(USART1,USART_FLAG_TC);
  }
}
void USART2_IRQHandler(void)
{
if(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == SET)
  {
    USART_ClearFlag(USART2,USART_FLAG_RXNE);
    USART_SendData(USART2,USART_ReceiveData(USART2));
        while(USART_GetFlagStatus(USART2, USART_FLAG_TC) == RESET);
    USART_ClearFlag(USART2,USART_FLAG_TC);
  }

}