FreeRTOS队列操作

API函数

//创建
#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
    #define xQueueCreate( uxQueueLength, uxItemSize ) 
            xQueueGenericCreate( ( uxQueueLength ), ( uxItemSize ), ( queueQUEUE_TYPE_BASE ) )
#endif
QueueHandle_t xQueueGenericCreate( const UBaseType_t uxQueueLength, 
                                const UBaseType_t uxItemSize, const uint8_t ucQueueType )

#define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) 
        xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
BaseType_t xQueueGenericSend( QueueHandle_t xQueue, const void * const pvItemToQueue, 
                            TickType_t xTicksToWait, const BaseType_t xCopyPosition )

#define xQueueReceive( xQueue, pvBuffer, xTicksToWait ) 
        xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE )
BaseType_t xQueueGenericReceive( QueueHandle_t xQueue, void * const pvBuffer, 
                                TickType_t xTicksToWait, const BaseType_t xJustPeeking )

//队列剩余大小
UBaseType_t uxQueueSpacesAvailable( const QueueHandle_t xQueue )

//队列使用大小
UBaseType_t uxQueueMessagesWaiting( const QueueHandle_t xQueue )

使用举例

QueueHandle_t Key_Queue //按键值消息队列句柄

void start_task(void *pvParameters)
{
    Key_Queue = xQueueCreate(1, sizeof(u8));
    if(Key_Queue == 0)
    {
        printf("xQueueCreate err\r\n");
    }
}

void key_task(void *pvParameters)
{
    BaseType_t ret;

    while(1)
    {
        key = KEY_Scan(0);              //扫描按键
        if((Key_Queue != 0) && (key))   //消息队列Key_Queue创建成功,并且按键被按下
        {
            ret = xQueueSend(Key_Queue, &key, 10);
            if(ret != pdPASS)           //发送按键值
            {
                printf("xQueueSend err\r\n");
            }
        }

        vTaskDelay(10);
    }
}

void recv_task(void *pvParameters)
{
    while(1)
    {
        if(Key_Queue != 0)
        {
            if(xQueueReceive(Key_Queue, &key, portMAX_DELAY))
            {
                printf("recv_task key %d\r\n", key);
            }
        }
    }
}

实验现象
点击按键

中断相关API函数

#define xQueueSendFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) 
                        xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), 
                        ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
BaseType_t xQueueGenericSendFromISR( QueueHandle_t xQueue, const void * const pvItemToQueue, 
                    BaseType_t * const pxHigherPriorityTaskWoken, const BaseType_t xCopyPosition )

BaseType_t xQueueReceiveFromISR( QueueHandle_t xQueue, void * const pvBuffer, 
                                BaseType_t * const pxHigherPriorityTaskWoken )

使用举例

void start_task(void *pvParameters)
{
    Message_Queue = xQueueCreate(1, sizeof(u8));
    if(Message_Queue == 0)
    {
        printf("xQueueCreate err\r\n");
    }
}

void USART1_IRQHandler(void)
{
    u8 Res;
    BaseType_t xHigherPriorityTaskWoken;

    if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
    {
        Res = USART_ReceiveData(USART1);

        xQueueSendFromISR(Message_Queue, &Res, &xHigherPriorityTaskWoken);

        portYIELD_FROM_ISR(xHigherPriorityTaskWoken); //如果需要的话进行一次任务切换
    }
}

void TIM2_IRQHandler(void)
{
    u8 Res;
    BaseType_t ret;
    BaseType_t xTaskWokenByReceive = pdFALSE;

    if(TIM_GetITStatus(TIM2, TIM_IT_Update) == SET)
    {
        TIM_ClearITPendingBit(TIM2, TIM_IT_Update); 

        ret = xQueueReceiveFromISR(Message_Queue, &Res, &xTaskWokenByReceive);
        if(ret == pdTRUE)
        {
            printf("xQueueReceiveFromISR Res %c\r\n", Res);
        }

        portYIELD_FROM_ISR(xTaskWokenByReceive); //如果需要的话进行一次任务切换
    }
}

实验现象