队列

队列创建

宏定义：configSUPPORT_STATIC_ALLOCATION

//静态创建
QueueHandle_t xQueueCreateStatic( UBaseType_t uxQueueLength, 
UBaseType_t uxItemSize,   
uint8_t *pucQueueStorageBuffer, 
StaticQueue_t *pxQueueBuffer ); 

/* The queue is to be created to hold a maximum of 10 uint64_t variables. */
#define QUEUE_LENGTH 10
#define ITEM_SIZE sizeof( uint64_t )
/* The variable used to hold the queue's data structure. */
static StaticQueue_t xStaticQueue;
/* The array to use as the queue's storage area. This must be at least
(uxQueueLength * uxItemSize) bytes. 至少队列最大长度，用于保存队列数据*/
uint8_t ucQueueStorageArea[ QUEUE_LENGTH * ITEM_SIZE ];

QueueHandle_t xQueue;
 /* Create a queue capable of containing 10 uint64_t values. */
 xQueue = xQueueCreateStatic( QUEUE_LENGTH,
 ITEM_SIZE,
 ucQueueStorageArea,
 &xStaticQueue );



//动态创建：FreeRTOS进行RAM分配队列存储空间
/* Define the data type that will be queued. */
typedef struct A_Message
{
char ucMessageID;
char ucData[ 20 ];
} AMessage;
 
/* Define the queue parameters. */
#define QUEUE_LENGTH 5
#define QUEUE_ITEM_SIZE sizeof( AMessage )
xQueue = xQueueCreate( QUEUE_LENGTH, QUEUE_ITEM_SIZE );  //创建队列，不需要提供队列数据存储地方
vQueueDelete( xQueue );  //队列删除

队列接收

//队列数据接收
BaseType_t xQueueReceive( QueueHandle_t xQueue, 
 void *pvBuffer, 
 TickType_t xTicksToWait );



/* Create a task, passing in the queue handle as the task parameter. */
 xTaskCreate( vAnotherTask, 
 “Task”, 
 STACK_SIZE, 
 ( void * ) xQueue, /* The queue handle is used as the task parameter. */
 TASK_PRIORITY, 
 NULL );

void vAnotherTask( void *pvParameters )
{
QueueHandle_t xQueue;
AMessage xMessage;
 
 /* The queue handle is passed into this task as the task parameter. Cast the 
 void * parameter back to a queue handle. */
 xQueue = ( QueueHandle_t ) pvParameters;
 
 for( ;; )
 {
 /* Wait for the maximum period for data to become available on the queue. 
 The period will be indefinite if INCLUDE_vTaskSuspend is set to 1 in 
 FreeRTOSConfig.h. */
 if( xQueueReceive( xQueue, &xMessage, portMAX_DELAY ) != pdPASS )
 {
 /* Nothing was received from the queue – even after blocking to wait
 for data to arrive. */
 }
 else
 {
 /* xMessage now contains the received data. */
 }
 }
}


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

/*Note
1. xQueueReceiveFromISR()调用能使任务从block状态解除
2. xQueueReceiveFromISR()只能指明是否进行一个上下文切换请求
3. 不能在任务调度之前调用，即任务调度之前就能响应的中断不能调用该函数接口
*/

//重置队列 队列中所有数据都将被丢弃

BaseType_t xQueueReset( QueueHandle_t xQueue );

 

 

队列发送：

BaseType_t xQueueSend( QueueHandle_t xQueue, 
 const void * pvItemToQueue, 
 TickType_t xTicksToWait );
BaseType_t xQueueSendToFront( QueueHandle_t xQueue, 
 const void * pvItemToQueue, 
 TickType_t xTicksToWait );
BaseType_t xQueueSendToBack( QueueHandle_t xQueue, 
 const void * pvItemToQueue, 
 TickType_t xTicksToWait );
//xQueueSend() and xQueueSendToBack() perform the same operation so are equivalent.

BaseType_t xQueueSendFromISR( QueueHandle_t xQueue, 
 const void *pvItemToQueue, 
 BaseType_t *pxHigherPriorityTaskWoken );
BaseType_t xQueueSendToBackFromISR( QueueHandle_t xQueue, 
 const void *pvItemToQueue, 
 BaseType_t *pxHigherPriorityTaskWoken );
BaseType_t xQueueSendToFrontFromISR( QueueHandle_t xQueue, 
 const void *pvItemToQueue, 
 BaseType_t *pxHigherPriorityTaskWoken );

 

 

队列查询：

//队列空查询
BaseType_t xQueueIsQueueEmptyFromISR( const QueueHandle_t pxQueue );

//队列full查询
BaseType_t xQueueIsQueueFullFromISR( const QueueHandle_t pxQueue );

//查询队列中有多少项
UBaseType_t uxQueueMessagesWaiting( const QueueHandle_t xQueue );

UBaseType_t uxQueueMessagesWaitingFromISR( const QueueHandle_t xQueue );


//队列overwrite操作 主要用于队列长度为1 的队列，表示一种状态
BaseType_t xQueueOverwrite( QueueHandle_t xQueue, const void *pvItemToQueue );

BaseType_t xQueueOverwriteFromISR( QueueHandle_t xQueue, 
 const void *pvItemToQueue,
 BaseType_t *pxHigherPriorityTaskWoken );
/*pxHigherPriorityTaskWoken：如果overwrite操作导致一个block任务为unblock，且优先级比当前task高，将pxHigherPriorityTaskWoken设置为TRUE*/

//读取数据，但不将该数据从队列中移除 返回一个项目的数据
BaseType_t xQueuePeek( QueueHandle_t xQueue, 
 void *pvBuffer, TickType_t
 xTicksToWait );


BaseType_t xQueuePeekFromISR( QueueHandle_t xQueue, void *pvBuffer );

 

 

队列集：

//队列集创建：
xActivatedMember = xQueueSelectFromSet( xQueueSet, pdMS_TO_TICKS( 200 ) );

//从队列集中移除某项：
if( xQueueRemoveFromSet( xQueue, xQueueSet ) != pdPASS )

//从队列集中读取数据

QueueSetMemberHandle_t xQueueSelectFromSet( QueueSetHandle_t xQueueSet,

const TickType_t xTicksToWait );

 

QueueSetMemberHandle_t xQueueSelectFromSetFromISR( QueueSetHandle_t xQueueSet );