5 HAL库正常驱动的UART，使用rt-thread无法正常驱动

发布于 2021-08-29 11:38:10 浏览：1314 订阅该版

事情经过是这样：我使用RT-Thread UART V2版本开驱动串口进行开发，在串口1（用于调试，无负载）、串口2（DMA收发，用于外部485通信）、串口３（DMA，与板载sim800c通信）。
在使用过程中串口1、2均能正常读写，但是串口3在使用中却无法正常驱动，主要表现为：执行类似代码：`rt_device_write(uart3, 0, "OK\r\n", 4)`成功，但是却并无数据输出。
进行跟踪调试，底层HAL库也成功执行（此时无输出）。
配置如下：
![image.png](https://oss-club.rt-thread.org/uploads/20210829/9ce81e459a5a6ab531ac350e7e80cb27.png)
![image.png](https://oss-club.rt-thread.org/uploads/20210829/3565a867fdfa5d775145e4144efdd990.png)
![image.png](https://oss-club.rt-thread.org/uploads/20210829/7e0eb7f0c19cc0b57b7557d26401d32b.png)

代码如下：
```c
int main(void)
{
    MX_USART3_UART_Init();
    sim800c_restart();
    /* 查找串口设备 */
    rt_device_t uart3 = rt_device_find(UART_Sim800C);
    rt_device_open(uart3, RT_DEVICE_FLAG_RX_NON_BLOCKING | RT_DEVICE_FLAG_TX_BLOCKING);

char *str = "OK\r\n";
    while (1)
    {
        rt_device_write(uart3,0,str,4);
        rt_thread_mdelay(1000);
    }

return RT_EOK;
}
```
有通过cubeMx重建单独测试项目，测试串口3的DMA功能，完好收发。配置如下图
![image.png](https://oss-club.rt-thread.org/uploads/20210829/671c7d9f1e4b69f5b6d26506f85883ab.png.webp)
![image.png](https://oss-club.rt-thread.org/uploads/20210829/1ce175ac55e3f00a039e8b6bbbad44cb.png.webp)

代码如下：
```c
/* USER CODE END 0 */

UART_HandleTypeDef huart3;
DMA_HandleTypeDef hdma_usart3_rx;
DMA_HandleTypeDef hdma_usart3_tx;

/* USART3 init function */

void MX_USART3_UART_Init(void)
{

huart3.Instance = USART3;
  huart3.Init.BaudRate = 115200;
  huart3.Init.WordLength = UART_WORDLENGTH_8B;
  huart3.Init.StopBits = UART_STOPBITS_1;
  huart3.Init.Parity = UART_PARITY_NONE;
  huart3.Init.Mode = UART_MODE_TX_RX;
  huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart3.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart3) != HAL_OK)
  {
    Error_Handler();
  }

}

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{

GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(uartHandle->Instance==USART3)
  {
  /* USER CODE BEGIN USART3_MspInit 0 */

/* USER CODE END USART3_MspInit 0 */
    /* USART3 clock enable */
    __HAL_RCC_USART3_CLK_ENABLE();
  
    __HAL_RCC_GPIOB_CLK_ENABLE();
    /**USART3 GPIO Configuration    
    PB10     ------> USART3_TX
    PB11     ------> USART3_RX 
    */
    GPIO_InitStruct.Pin = GPIO_PIN_10;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

GPIO_InitStruct.Pin = GPIO_PIN_11;
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

/* USART3 DMA Init */
    /* USART3_RX Init */
    hdma_usart3_rx.Instance = DMA1_Channel3;
    hdma_usart3_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_usart3_rx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_usart3_rx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_usart3_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_usart3_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_usart3_rx.Init.Mode = DMA_NORMAL;
    hdma_usart3_rx.Init.Priority = DMA_PRIORITY_LOW;
    if (HAL_DMA_Init(&hdma_usart3_rx) != HAL_OK)
    {
      Error_Handler();
    }

__HAL_LINKDMA(uartHandle,hdmarx,hdma_usart3_rx);

/* USART3_TX Init */
    hdma_usart3_tx.Instance = DMA1_Channel2;
    hdma_usart3_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
    hdma_usart3_tx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_usart3_tx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_usart3_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_usart3_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_usart3_tx.Init.Mode = DMA_NORMAL;
    hdma_usart3_tx.Init.Priority = DMA_PRIORITY_LOW;
    if (HAL_DMA_Init(&hdma_usart3_tx) != HAL_OK)
    {
      Error_Handler();
    }

__HAL_LINKDMA(uartHandle,hdmatx,hdma_usart3_tx);

/* USART3 interrupt Init */
    HAL_NVIC_SetPriority(USART3_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(USART3_IRQn);
  /* USER CODE BEGIN USART3_MspInit 1 */

/* USER CODE END USART3_MspInit 1 */
  }
}
```
```
/* USER CODE BEGIN 0 */
extern UART_HandleTypeDef huart3;
/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
  /* USER CODE BEGIN 1 */

/* USER CODE END 1 */

/* MCU Configuration--------------------------------------------------------*/

/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

/* USER CODE BEGIN Init */

/* USER CODE END Init */

/* Configure the system clock */
  SystemClock_Config();

/* USER CODE BEGIN SysInit */

/* USER CODE END SysInit */

/* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_USART3_UART_Init();
  /* USER CODE BEGIN 2 */

/* USER CODE END 2 */