rt-thread中STM32L431 的LPUART1 open失败的原因

STM32L431 的LPUART1 是低功耗串口,使用LSE或LSI时最大支持9600波特率,大于此波特率需要用PCLK1或SYSCLK,同时如果选择用PCLK1或SYSCLK时波特率必须大于9600,否则初始化会失败

if (HAL_UART_Init(&uart->handle) != HAL_OK)
    {
        return -RT_ERROR;
    }

rt-thread中open device时会先初始化此设备,当打开LPUART1时如果波特率设置有问题则初始化返回失败,导致open失败

 

低于9600(含)选RCC_LPUART1CLKSOURCE_LSE

否则选择RCC_LPUART1CLKSOURCE_PCLK1

 

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
  if(uartHandle->Instance==LPUART1)
  {
  /* USER CODE BEGIN LPUART1_MspInit 0 */

  /* USER CODE END LPUART1_MspInit 0 */
  /** Initializes the peripherals clock
  */
    PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
    PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_LSE;//≤9600选LSE
    if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
    {
      Error_Handler();
    }

    /* LPUART1 clock enable */
    __HAL_RCC_LPUART1_CLK_ENABLE();

    __HAL_RCC_GPIOC_CLK_ENABLE();
    /**LPUART1 GPIO Configuration
    PC0     ------> LPUART1_RX
    PC1     ------> LPUART1_TX
    */
    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF8_LPUART1;
    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /* USER CODE BEGIN LPUART1_MspInit 1 */

  /* USER CODE END LPUART1_MspInit 1 */
  }
}