请教STM32F73 串口3的问题，一直很纠结，给位帮帮忙。

-1127 · 2013-8-16 16:52

本帖最后由 youki1234 于 2013-8-16 16:57 编辑

用下面的代码初始化后，串口接收、发送单个字符都没有问题。但如果上位机连续发两个字符给串口3时，第二个字符就会有问题。例如：

上位机发  0xAA 下位机回的就是0xAA

但如果上位机发0xAA 0xAA,下位机回的就是0xAA 0xF5 (应该回0xAA 0xAA)

大家有没有碰到过类似的问题啊？或者哪位大侠能发个373能用的UART3的代码，谢谢了。。。

UART3用的是PB8，PB9, 同样的代码在UART1和UART2中使用都没有问题。

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初始化代码如下：

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB , ENABLE);

  /* Connect pin to Periph */
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_7);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_7);

  /* Configure pins as AF pushpull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  USART_DeInit(USART3);
  USART_InitStructure.USART_BaudRate = baud;
  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_Rx | USART_Mode_Tx;
  USART_Init(USART3, &USART_InitStructure);

/* USART enable */
  USART_Cmd(USART3, ENABLE);
  USART_ITConfig(USART3,USART_IT_RXNE,ENABLE);

中断处理函数代码如下：
if(USART_GetFlagStatus(USART3, USART_FLAG_RXNE) == SET)
{
   temp3 = USART_ReceiveData(USART3);
   }
if(USART_GetFlagStatus(USART3,USART_FLAG_ORE)==SET)
{
      USART_ClearFlag(USART3,USART_FLAG_ORE); //????
      USART_ReceiveData(USART3);             //?DR
}
RecvBUF3[COUNT3++]=temp3;
if(COUNT3==20)
   COUNT3=0;

Uart_Put(3,temp3);//收到一个字符就返回一个字符。
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