串口選擇

示例給出的是串口的，因為今天回老家，帶的杜綁線(xiàn)是公對母的，不能接串口1，所以選擇串口2，即PA2--TX，PA3--RX。

初始化串口

1. 初始化UART2的時(shí)鐘：__RCC_UART2_CLK_ENABLE();
2. 初始化GPIOA外設時(shí)鐘：RCC_AHBPeriphClk_Enable( RCC_AHB_PERIPH_GPIOA, ENABLE);
3. 復用PA2為UART2TX： PA02_AFx_UART2TXD();
4. 復用PA3為UART2RX：PA03_AFx_UART2RXD();
5. 初始化PA2為高速輸出模式：

GPIO_InitStructure.Pins = GPIO_PIN_2; //PA2
  GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStructure.Speed = GPIO_SPEED_HIGH;
  GPIO_Init(CW_GPIOA, &GPIO_InitStructure);

6. 初始化PA3為上拉輸入：

GPIO_InitStructure.Pins = GPIO_PIN_3; //PA3
  GPIO_InitStructure.Mode = GPIO_MODE_INPUT_PULLUP;
  GPIO_Init(CW_GPIOA, &GPIO_InitStructure);

7. 初始化UART2配置為9600波特率：

USART_InitStructure.USART_BaudRate = 9600;
  USART_InitStructure.USART_Over = USART_Over_16;
  USART_InitStructure.USART_Source = USART_Source_PCLK;
  USART_InitStructure.USART_UclkFreq = 64000000;
  USART_InitStructure.USART_StartBit = USART_StartBit_FE;
  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(CW_UART2, &USART_InitStructure);

8. 使能中斷輸入

//使能UARTx RC中斷
  USART_ITConfig(CW_UART2, USART_IT_RC, ENABLE);
  //優(yōu)先級，無(wú)優(yōu)先級分組
  NVIC_SetPriority(UART2_IRQn, 0);
  //UARTx中斷使能
  NVIC_EnableIRQ(UART2_IRQn);

9. 中斷接收函數，主要功能為判斷接收到的第一位是否為0，第二位是否為1，如果總接收長(cháng)度為4位，測翻轉LED4，具體代碼如下：

void UART2_IRQHandler(void)
{
  /* USER CODE BEGIN */
  unsigned char TxRxBuffer;
  if(USART_GetITStatus(CW_UART2, USART_IT_RC) != RESET)
  { 
		USART_ClearITPendingBit(CW_UART2, USART_IT_RC); 
    TxRxBuffer = USART_ReceiveData_8bit(CW_UART2);
			rec[re_count]=TxRxBuffer;
		 if (re_count == 0&&rec[0]==0x00)
			{          
				rev_start=1;
				re_count++;
			}
			else if(rev_start==1)
			{		
				if(re_count==1&&rec[1]!=0x01)
				{
					re_count=0;rev_start=0;
				}
				else if(re_count==4)           //計算總個(gè)數，0-4 
			      {check_flag=1;re_count=0;rev_start=0;}	  //如果對，那么將標志位置1，并清除里面的值從新接收
				else		
				   re_count++;		
			}
  }
  /* USER CODE END */
}

實(shí)現效果，下載后，串口接收到0x00 0x01 0x02 0x03 ,HEX發(fā)送00 01 02 03 可以實(shí)現LED4的翻轉：

審核編輯：湯梓紅