菜鸟提问，STM32F3X 串口UART

黑色幽默diablo 提问时间：2015-6-27 14:03 /

最近在做STM32F3x系列的串口实验，使用中断一直无法接受发送数据，不知道哪里错了，请大神们指教。
程序：
void My_USART1_Init(void)
{
GPIO_InitTypeDef  GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA,ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);//使能USART1时钟

  GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_7);
  GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_7);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 ;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

USART_InitStructure.USART_BaudRate=115200;
USART_InitStructure.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode=USART_Mode_Rx|USART_Mode_Tx;
USART_InitStructure.USART_Parity=USART_Parity_No;
USART_InitStructure.USART_StopBits=USART_StopBits_1;
USART_InitStructure.USART_WordLength=USART_WordLength_8b;

USART_Init(USART1,&USART_InitStructure);

USART_Cmd(USART1 ,ENABLE);
      USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
      USART_ITConfig(USART1,USART_IT_TXE,ENABLE);

NVIC_InitStructure.NVIC_IRQChannel=USART1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;
NVIC_Init(&NVIC_InitStructure);

}

void USART1_IRQHandler(void)
{
uint16_t res;
if(USART_GetITStatus(USART1,USART_IT_RXNE)==SET){

res=USART_ReceiveData(USART1);
USART_SendData(USART1,res);
}

}

int main(void)
{
My_USART1_Init();
while(1){};
}

另本人不明白，USART1_IRQHandler（）函数是自动被调用吗？main()函数里没有这个函数？