stm32使用HAL_UART_Transmit()函数将收到的dht11数据通过串口发送数据到HC-05

首先需要在代码中初始化串口和DHT11。假设串口使用USART1，DHT11连接到PA0引脚。

UART_HandleTypeDef huart1;

void MX_USART1_UART_Init(void)
{
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 9600;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart1) != HAL_OK)
  {
    Error_Handler();
  }
}

void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  __HAL_RCC_GPIOA_CLK_ENABLE();

  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, GPIO_PIN_RESET);

  GPIO_InitStruct.Pin = GPIO_PIN_0;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

void DHT11_Start(void)
{
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, GPIO_PIN_RESET);
  HAL_Delay(18);
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, GPIO_PIN_SET);
  HAL_Delay(40);
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, GPIO_PIN_RESET);
}

uint8_t DHT11_Check_Response(void)
{
  uint8_t Response = 0;
  HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0);
  HAL_Delay(10);
  if (!HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0))
  {
    HAL_Delay(80);
    if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0))
      Response = 1;
  }
  while (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0))
    ;
  return Response;
}

uint8_t DHT11_Read_Data(void)
{
  uint8_t i, j;
  for (j = 0; j < 8; j++)
  {
    while (!HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0))
      ;
    HAL_Delay(40);
    if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0) == 0)
    {
      i &= ~(1 << (7 - j));
    }
    else
    {
      i |= (1 << (7 - j));
      while (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0))
        ;
    }
  }
  return i;
}

然后在主函数中，读取DHT11数据并发送到HC-05。

int main(void)
{
  uint8_t hum_int, hum_dec, temp_int, temp_dec, check_sum;
  MX_GPIO_Init();
  MX_USART1_UART_Init();
  while (1)
  {
    DHT11_Start();
    if (DHT11_Check_Response())
    {
      hum_int = DHT11_Read_Data();
      hum_dec = DHT11_Read_Data();
      temp_int = DHT11_Read_Data();
      temp_dec = DHT11_Read_Data();
      check_sum = DHT11_Read_Data();
      if ((hum_int + hum_dec + temp_int + temp_dec) == check_sum)
      {
        char data[50];
        sprintf(data, "Humidity: %d.%d%%, Temperature: %d.%dC\r\n", hum_int, hum_dec, temp_int, temp_dec);
        HAL_UART_Transmit(&huart1, (uint8_t *)data, strlen(data), HAL_MAX_DELAY);
      }
    }
    HAL_Delay(2000);
  }
}

在上面的代码中，我们使用sprintf()函数将DHT11数据格式化为字符串，然后使用HAL_UART_Transmit()函数将其发送到HC-05。请注意，我们将字符串转换为uint8_t型数组，并计算它的长度。在HAL_UART_Transmit()函数中，我们使用HAL_MAX_DELAY作为超时参数，以确保数据完全发送。