STM32 HAL库串口注意点

现象

STM32CubeMX提供了串口的HAL库，网上能找到很多例子，但是真正运行起来会时不时卡死。

原因

代码中使用了在

1	void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)

函数中调用

1	HAL_StatusTypeDef HAL_UART_Receive_IT(UART_HandleTypeDef huart, uint8_t pData, uint16_t Size)

重新启动中断，并将数据送入队列的方法。

会造成两个问题：

HAL_UART_Receive_IT中检测__HAL_LOCK(huart)，中断外调用HAL_UART_Transmit时也会锁定此huart，再进入接收中断时有几率造成死锁。
发生OverRun错误会停止中断。

解决方法

定期检测串口，防止死锁造成的无法恢复的失败。
写好HAL_UART_ErrorCallback函数。

// define and initial variables outside
extern UART_HandleTypeDef huart3;
volatile char data;
extern osMessageQId rxQHandle;

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
    if (huart->Instance == USART3){
        BaseType_t xHigherPriorityTaskWoken;
        xHigherPriorityTaskWoken = pdTRUE;
        xQueueSendFromISR(rxQHandle, (void*)&data, &xHigherPriorityTaskWoken);
        if (HAL_UART_Receive_IT(huart, (uint8_t*)&data ,1) != HAL_OK){
            // fail ++;
        }
    }
}

void HAL_UART_ErrorCallback(UART_HandleTypeDef* huart){
    uint32_t isrflags = READ_REG(huart->Instance->SR);
    if((__HAL_UART_GET_FLAG(huart, UART_FLAG_PE))!=RESET)
    {
        __HAL_UART_CLEAR_PEFLAG(huart);
    }
    if((__HAL_UART_GET_FLAG(huart, UART_FLAG_FE))!=RESET)
    {
        __HAL_UART_CLEAR_FEFLAG(huart);
    }
    if((__HAL_UART_GET_FLAG(huart, UART_FLAG_NE))!=RESET)
    {
        __HAL_UART_CLEAR_NEFLAG(huart);
    }
    if((__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE))!=RESET)
    {
        __HAL_UART_CLEAR_OREFLAG(huart);
    }
    huart->RxState = HAL_UART_STATE_READY;
    huart->ErrorCode = HAL_UART_ERROR_NONE;

    __HAL_UART_DISABLE_IT(huart, UART_IT_RXNE);
    __HAL_UART_DISABLE_IT(huart, UART_IT_PE);
    __HAL_UART_DISABLE_IT(huart, UART_IT_ERR);


    if (huart->Instance == USART3){
        if (HAL_UART_Receive_IT(huart, (uint8_t*)&data ,1) != HAL_OK){
        }
    }
}

void call_this_function_periodically(ali_cloud* app){
    if ((__HAL_UART_GET_FLAG(&huart3, UART_FLAG_ORE) != RESET) || (huart3.Instance->CR1 & USART_CR1_RXNEIE == RESET)) {
        __disable_irq();
        HAL_UART_ErrorCallback(&huart3);
        __enable_irq();
    }
}