STM32使用USART初始化设置停止位为1，示波器实际测量是2位，是什么原因呢？请高手帮忙看看
初始化部分代码：
        USART_InitStructure.USART_BaudRate = bound;
        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;       

       USART_Init(USART1, &USART_InitStructure);
       USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
       USART_Cmd(USART1, ENABLE);

串口发送数据部分代码：
        for(i=0;i<DataLen;i++)
        {
            USART_SendData(USART1, DMX_buf[i]);
            while(USART_GetFlagStatus(USART1,USART_FLAG_TC)!=SET);
        }