转：开始打怪——UART

串口初始化使用UART_HandleTypeDef类型的结构体。以9600波特率、8位数据、1位停止位的配置程序如下：

查看原代码

•   UartHandle.Init.BaudRate   = 9600;
  
•   UartHandle.Init.WordLength = UART_WORDLENGTH_8B;
  
•   UartHandle.Init.StopBits   = UART_STOPBITS_1;
  
•   UartHandle.Init.Parity     = UART_PARITY_NONE;
  
•   UartHandle.Init.HwFlowCtl  = UART_HWCONTROL_NONE;
  
•   UartHandle.Init.Mode       = UART_MODE_TX_RX;
  
•   UartHandle.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  
• 
  
  

使用HAL_UART_DeInit函数将串口的配置默认，再使用HAL_UART_Init函数，将上面的结构体的配置写入到寄存器中。

串口初始化使用UART_HandleTypeDef类型的结构体。以9600波特率、8位数据、1位停止位的配置程序如下：

查看原代码
  UartHandle.Init.BaudRate   = 9600;
  UartHandle.Init.WordLength = UART_WORDLENGTH_8B;
  UartHandle.Init.StopBits   = UART_STOPBITS_1;
  UartHandle.Init.Parity     = UART_PARITY_NONE;
  UartHandle.Init.HwFlowCtl  = UART_HWCONTROL_NONE;
  UartHandle.Init.Mode       = UART_MODE_TX_RX;
  UartHandle.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;

使用HAL_UART_DeInit函数将串口的配置默认，再使用HAL_UART_Init函数，将上面的结构体的配置写入到寄存器中。

最终实现的函数如下：

查看原代码
HAL_StatusTypeDef UART_SetConfig(UART_HandleTypeDef *huart)
{
  uint32_t tmpreg                     = 0x00000000U;
  UART_ClockSourceTypeDef clocksource = UART_CLOCKSOURCE_UNDEFINED;
  uint16_t brrtemp                    = 0x0000U;
  uint16_t usartdiv                   = 0x0000U;
  HAL_StatusTypeDef ret               = HAL_OK;

  /* Check the parameters */
  assert_param(IS_UART_BAUDRATE(huart->Init.BaudRate));
  assert_param(IS_UART_WORD_LENGTH(huart->Init.WordLength));
  assert_param(IS_UART_STOPBITS(huart->Init.StopBits));
  assert_param(IS_UART_PARITY(huart->Init.Parity));
  assert_param(IS_UART_MODE(huart->Init.Mode));
  assert_param(IS_UART_HARDWARE_FLOW_CONTROL(huart->Init.HwFlowCtl));
  assert_param(IS_UART_ONE_BIT_SAMPLE(huart->Init.OneBitSampling));


  /*-------------------------- USART CR1 Configuration -----------------------*/
  /* Clear M, PCE, PS, TE, RE and OVER8 bits and configure
   *  the UART Word Length, Parity, Mode and oversampling:
   *  set the M bits according to huart->Init.WordLength value
   *  set PCE and PS bits according to huart->Init.Parity value
   *  set TE and RE bits according to huart->Init.Mode value
   *  set OVER8 bit according to huart->Init.OverSampling value */
  tmpreg = (uint32_t)huart->Init.WordLength | huart->Init.Parity | huart->Init.Mode | huart->Init.OverSampling ;
  MODIFY_REG(huart->Instance->CR1, UART_CR1_FIELDS, tmpreg);

  /*-------------------------- USART CR2 Configuration -----------------------*/
  /* Configure the UART Stop Bits: Set STOP[13:12] bits according
   * to huart->Init.StopBits value */
  MODIFY_REG(huart->Instance->CR2, USART_CR2_STOP, huart->Init.StopBits);

  /*-------------------------- USART CR3 Configuration -----------------------*/
  /* Configure
   * - UART HardWare Flow Control: set CTSE and RTSE bits according
   *   to huart->Init.HwFlowCtl value
   * - one-bit sampling method versus three samples' majority rule according
   *   to huart->Init.OneBitSampling */
  tmpreg = (uint32_t)huart->Init.HwFlowCtl | huart->Init.OneBitSampling ;
  MODIFY_REG(huart->Instance->CR3, (USART_CR3_RTSE | USART_CR3_CTSE | USART_CR3_ONEBIT), tmpreg);

  /*-------------------------- USART BRR Configuration -----------------------*/
  UART_GETCLOCKSOURCE(huart, clocksource);

  /* Check UART Over Sampling to set Baud Rate Register */
  if (huart->Init.OverSampling == UART_OVERSAMPLING_8)
  {
    switch (clocksource)
    {
    case UART_CLOCKSOURCE_PCLK1:
        usartdiv = (uint16_t)(UART_DIV_SAMPLING8(HAL_RCC_GetPCLK1Freq(), huart->Init.BaudRate));
      break;
    case UART_CLOCKSOURCE_PCLK2:
        usartdiv = (uint16_t)(UART_DIV_SAMPLING8(HAL_RCC_GetPCLK2Freq(), huart->Init.BaudRate));
      break;
    case UART_CLOCKSOURCE_HSI:
        usartdiv = (uint16_t)(UART_DIV_SAMPLING8(HSI_VALUE, huart->Init.BaudRate));
      break;
    case UART_CLOCKSOURCE_SYSCLK:
        usartdiv = (uint16_t)(UART_DIV_SAMPLING8(HAL_RCC_GetSysClockFreq(), huart->Init.BaudRate));
      break;
    case UART_CLOCKSOURCE_LSE:
        usartdiv = (uint16_t)(UART_DIV_SAMPLING8(LSE_VALUE, huart->Init.BaudRate));
      break;
      case UART_CLOCKSOURCE_UNDEFINED:
    default:
        ret = HAL_ERROR;
      break;
    }

    brrtemp = usartdiv & 0xFFF0U;
    brrtemp |= (uint16_t)((usartdiv & (uint16_t)0x000FU) >> 1U);
    huart->Instance->BRR = brrtemp;
  }
  else
  {
    switch (clocksource)
    {
    case UART_CLOCKSOURCE_PCLK1:
        huart->Instance->BRR = (uint16_t)(UART_DIV_SAMPLING16(HAL_RCC_GetPCLK1Freq(), huart->Init.BaudRate));
      break;
    case UART_CLOCKSOURCE_PCLK2:
        huart->Instance->BRR = (uint16_t)(UART_DIV_SAMPLING16(HAL_RCC_GetPCLK2Freq(), huart->Init.BaudRate));
      break;
    case UART_CLOCKSOURCE_HSI:
        huart->Instance->BRR = (uint16_t)(UART_DIV_SAMPLING16(HSI_VALUE, huart->Init.BaudRate));
      break;
    case UART_CLOCKSOURCE_SYSCLK:
        huart->Instance->BRR = (uint16_t)(UART_DIV_SAMPLING16(HAL_RCC_GetSysClockFreq(), huart->Init.BaudRate));
      break;
    case UART_CLOCKSOURCE_LSE:
        huart->Instance->BRR = (uint16_t)(UART_DIV_SAMPLING16(LSE_VALUE, huart->Init.BaudRate));
      break;
      case UART_CLOCKSOURCE_UNDEFINED:
    default:
        ret = HAL_ERROR;
      break;
    }
  }

  return ret;

}

从如下的宏定义，可看到，使用的是串口6，GPIO使用的是GPIOC的6、7引脚。

这两个引脚连接到了Arduino上。

板子的连线如下图，接了一个串口。

运行结果，按下按键后，会在串口终端中输出如下：

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