串口1 DMA发送9位格式串口无输出是什么原因？

看了好多遍，感觉没啥问题啊


void USART1_CFG(void)
{
  GPIO_InitTypeDef  GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef  NVIC_InitStructure;


    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);


  /* USART2 TX-->A.2   RX-->A.3 */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOAtiNG;
    GPIO_Init(GPIOA, &GPIO_InitStructure);


    USART_InitStructure.USART_BaudRate = 250000;
    USART_InitStructure.USART_WordLength = USART_WordLength_9b;
    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_Tx ;    //DMX512这里只发送数据


  USART_Init(USART1, &USART_InitStructure);
//    USART_ITConfig(USART1, USART_IT_TXE, ENABLE);


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


//  DMA_Cmd(DMA1_Channel4, ENABLE);                                    /* USART1 Tx */
//  DMA_Cmd(DMA1_Channel5, ENABLE);                                    /* USART1 Rx */


  USART_Cmd(USART2, ENABLE);
}


/*******************************************************************************
* Function Name  : DMA_INIT
* Description    : Configures the DMA for USART1.
* Input          : None
* Return         : None
*******************************************************************************/
void DMA_INIT(void)
{
    DMA_InitTypeDef DMA_InitStructure;
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);


  DMA_DeInit(DMA1_Channel4);
  DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DATAR);  /* USART2->DATAR:0x40004404 */
  DMA_InitStructure.DMA_MemoryBaseAddr = (u32)Tx_Buffer;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
  DMA_InitStructure.DMA_BufferSize = DMX_CHN;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
  DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init(DMA1_Channel4, &DMA_InitStructure);


//    DMA_DeInit(DMA1_Channel5);
//  DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART2->DATAR);
//  DMA_InitStructure.DMA_MemoryBaseAddr = (u32)RxBuffer1;
//  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
//  DMA_InitStructure.DMA_BufferSize = TxSize2;
//  DMA_Init(DMA1_Channel5, &DMA_InitStructure);
}


void DMX_Init()        //初始化 主函数调用
{
    USART1_CFG();
    DMA_INIT();
    USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);//|USART_DMAReq_Rx
}
static void USART_Send9Data(void)
{
    uint16_t tmp;
    DMA_Cmd(DMA1_Channel4, DISABLE);                                    /* USART1 Tx */
    for(tmp=0;tmp
    {
       Tx_Buffer[tmp] = (uint16_t)DMX_SendData[tmp]+0x0100;        //数据第9位为高
    }
    DMA_Cmd(DMA1_Channel4, ENABLE);                                    /* USART1 Tx */
   
}