void My_UART5_Init(void)
{
GPIO_InitTypeDef  GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

 RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART5,ENABLE);//????USART1?±??
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC,ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD,ENABLE);

GPIO_PinAFConfig(GPIOC,GPIO_PinSource12,GPIO_AF_UART5);


 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

GPIO_PinAFConfig(GPIOD,GPIO_PinSource2,GPIO_AF_UART5);
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOD, &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(UART5,&USART_InitStructure);
USART_Cmd(UART5 ,ENABLE);
  
USART_ITConfig(UART5,USART_IT_RXNE,ENABLE);

NVIC_InitStructure.NVIC_IRQChannel=UART5_IRQn;
NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;
NVIC_Init(&NVIC_InitStructure);


}

void UART5_IRQHandler(void)
{
u8 res;
if(USART_GetITStatus(UART5,USART_IT_RXNE)){

res=USART_ReceiveData(UART5);
USART_SendData(UART5,res);
}

}