STM32F103VBT6的串口2不能发送数据，请FAE帮忙看一下，谢谢！

yang100 提问时间：2018-4-20 09:55 /

这几天调试modbus，使用STM32F103VBT6的串口2，在配置完成后查询方式和中断方式都不能发送数据。不知道是配置还是哪里出错，请帮忙看下，谢谢！
/**
  * @brief  串口初始化
  * @param  ucPORT    串口号
  *       ulBaudRate  波特率
  *       ucDataBits  数据位
  *       eParity    校验位
  * @retval None
  */
BOOL
xMBPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity )
{
  GPIO_InitTypeDef GPIO_InitStructure;
  USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
(void)ucPORT;    //不修改串口
  (void)ucDataBits; //不修改数据位长度
  (void)eParity; //不修改校验格式

  //使能USART2，GPIOA
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);//使能GPIOA时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);//使能USART2时钟

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; //PA2
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;//PA3
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; //浮空输入
  GPIO_Init(GPIOA, &GPIO_InitStructure);

// RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART2,ENABLE);//复位串口2
// RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART2,DISABLE);//停止复位

  USART_InitStructure.USART_BaudRate = ulBaudRate;          //只修改波特率
  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;
  //串口初始化
  USART_Init(USART2, &USART_InitStructure);

  USART_ITConfig(UART2, USART_IT_RXNE, ENABLE); /* 使能接收中断*/
  USART_ITConfig(UART2, USART_IT_TC, ENABLE); /* 使能接收中断*/

  //使能USART2
  USART_Cmd(USART2, ENABLE);

  USART_ClearFlag(UART2, USART_FLAG_TC);

  //设定USART2 中断优先级
  NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  return TRUE;
}

/**
  * @brief  通过串口发送数据
  * @param  None
  * @retval None
  */
BOOL
xMBPortSerialPutByte( CHAR ucByte )
{
  //发送数据
  USART_SendData(USART2, ucByte);
  return TRUE;
}

/**
  * @brief  从串口获得数据
  * @param  None
  * @retval None
  */
BOOL
xMBPortSerialGetByte( CHAR * pucByte )
{
  //接收数据
  *pucByte = USART_ReceiveData(USART2);
  return TRUE;
}

/* Create an interrupt handler for the transmit buffer empty interrupt
* (or an equivalent) for your target processor. This function should then
* call pxMBFrameCBTransmitterEmpty( ) which tells the protocol stack that
* a new character can be sent. The protocol stack will then call
* xMBPortSerialPutByte( ) to send the character.
*/
static void prvvUARTTxReadyISR( void )
{
  //mb.c eMBInit函数中
  //pxMBFrameCBTransmitterEmpty = xMBRTUTransmitFSM
  //发送状态机
  pxMBFrameCBTransmitterEmpty();
}

/* Create an interrupt handler for the receive interrupt for your target
* processor. This function should then call pxMBFrameCBByteReceived( ). The
* protocol stack will then call xMBPortSerialGetByte( ) to retrieve the
* character.
*/
static void prvvUARTRxISR( void )
{
  //mb.c eMBInit函数中
  //pxMBFrameCBByteReceived = xMBRTUReceiveFSM
  //接收状态机
  pxMBFrameCBByteReceived();
}

/**
  * @brief  USART2中断服务函数
  * @param  None
  * @retval None
  */
void USART2_IRQHandler(void)
{
  //发生接收中断
  if(USART_GetITStatus(USART2, USART_IT_RXNE) == SET)
  {
prvvUARTRxISR();
//清除中断标志位
USART_ClearITPendingBit(USART2, USART_IT_RXNE);
  }

  //发生完成中断
  if(USART_GetITStatus(USART2, USART_IT_TC) == SET)
  {
prvvUARTTxReadyISR();
//清除中断标志
USART_ClearITPendingBit(USART2, USART_IT_TC);
  }

}