1 串口

STM32串口中断接收和中断发送
 STM32 硬件UART接收超时检测设置

1.1 HAL_UART_Transmit_IT执行流程

HAL_StatusTypeDef HAL_UART_Transmit_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)

/* HAL_UART_Transmit_IT 函数 */
/* 1. 初始化发送缓存的指针和大小 */
huart->pTxBuffPtr  = pData;
huart->TxXferSize  = Size;
huart->TxXferCount = Size;
huart->TxISR       = NULL;

/* 2. 初始化发送完成中断处理函数 */
/* Set the Tx ISR function pointer according to the data word length */
if ((huart->Init.WordLength == UART_WORDLENGTH_9B) && (huart->Init.Parity == UART_PARITY_NONE))
      {
        huart->TxISR = UART_TxISR_16BIT;
      }
      else
      {
        huart->TxISR = UART_TxISR_8BIT;
      }

/* 3. 使能发送为空中断，打开该标志位后，串口会进入接收中断HAL_UART_IRQHandler */
/* Enable the Transmit Data Register Empty interrupt */
SET_BIT(huart->Instance->CR1, USART_CR1_TXEIE_TXFNFIE);

void HAL_UART_IRQHandler(UART_HandleTypeDef *huart)

/* 1. 判断串口中断是否为发送为空中断，如果是就发送数据 */
/* UART in mode Transmitter ------------------------------------------------*/
  if (((isrflags & USART_ISR_TXE_TXFNF) != 0U)
      && (((cr1its & USART_CR1_TXEIE_TXFNFIE) != 0U)
          || ((cr3its & USART_CR3_TXFTIE) != 0U)))
  {
  /* 2. 判断串口发送中断处理函数是否为空，如果不为空就发送数据 */
    if (huart->TxISR != NULL)
    {
      huart->TxISR(huart);
    }
    return;
  }
 /* 3. 判断串口数据是否发送完成，huart->TxISR发送完成后，会将USART_CR1_TCIE置1 */ 
 /* UART in mode Transmitter (transmission end) -----------------------------*/
  if (((isrflags & USART_ISR_TC) != 0U) && ((cr1its & USART_CR1_TCIE) != 0U))
  {
  	/* 3. 串口数据发送完成，复位发送状态及标志 */ 
    UART_EndTransmit_IT(huart);
    return;
  }

static void UART_TxISR_8BIT(UART_HandleTypeDef *huart)

/* Check that a Tx process is ongoing */
  if (huart->gState == HAL_UART_STATE_BUSY_TX)
  {
  	/* 判断数据是否发送完 */
    if (huart->TxXferCount == 0U)
    {
      /* 数据发送完成，关闭接收为空中断，使能发送完成中断 */
      /* Disable the UART Transmit Data Register Empty Interrupt */
      CLEAR_BIT(huart->Instance->CR1, USART_CR1_TXEIE_TXFNFIE);

      /* Enable the UART Transmit Complete Interrupt */
      SET_BIT(huart->Instance->CR1, USART_CR1_TCIE);
    }
    else
    {
     /* 数据没有发送完成，继续发送 */
      huart->Instance->TDR = (uint8_t)(*huart->pTxBuffPtr & (uint8_t)0xFF);
      huart->pTxBuffPtr++;
      huart->TxXferCount--;
    }
  }

static void UART_EndTransmit_IT(UART_HandleTypeDef *huart)

/* Disable the UART Transmit Complete Interrupt */
  CLEAR_BIT(huart->Instance->CR1, USART_CR1_TCIE);

  /* Tx process is ended, restore huart->gState to Ready */
  huart->gState = HAL_UART_STATE_READY;

  /* Cleat TxISR function pointer */
  huart->TxISR = NULL;

#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
  /*Call registered Tx complete callback*/
  huart->TxCpltCallback(huart);
#else
  /*Call legacy weak Tx complete callback*/
  HAL_UART_TxCpltCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */