stm32 串口连续接收 发送的出错的问题

/*
* 串口1 初始化
*/
void USART1_Initial(void)
{
USART_InitTypeDef USART_InitStruct;
GPIO_InitTypeDef GPIO_InitStructure;

// 设置复用到串口的IO口 PA10 PA11

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);//

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //USART1 TX
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出
GPIO_Init(GPIOA, &GPIO_InitStructure); //A端口

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; //USART1 RX
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; //复用开漏输入
GPIO_Init(GPIOA, &GPIO_InitStructure);


RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);//

USART_DeInit(USART1); //首先复位

/*!< This member configures the USART communication baud rate.
The baud rate is computed using the following formula:
- IntegerDivider = ((PCLKx) / (16 * (USART_InitStruct->USART_BaudRate)))
- FractionalDivider = ((IntegerDivider - ((u32) IntegerDivider)) * 16) + 0.5 */
USART_InitStruct.USART_BaudRate=2400;

USART_InitStruct.USART_WordLength=USART_WordLength_8b;

USART_InitStruct.USART_StopBits=USART_StopBits_1;

USART_InitStruct.USART_Parity=USART_Parity_No;

USART_InitStruct.USART_Mode=USART_Mode_Rx|USART_Mode_Tx;

USART_InitStruct.USART_HardwareFlowControl=USART_HardwareFlowControl_None;

USART_Init(USART1, &USART_InitStruct);

USART_ITConfig(USART1,USART_IT_RXNE,ENABLE); //USART1 接收中断使能

USART_Cmd(USART1,ENABLE); // USART1 模块使能
}