UCOSIII消息队列

迈不过友情╰ 2022-06-02 00:16 217阅读 0赞

**任务间消息传递2种途径**

> 全局变量  
> 发布消息

**主结构体**

typedef struct os_q OS_Q;
    struct  os_q {                            /* Message Queue */
    
        OS_OBJ_TYPE          Type;            /* Should be set to OS_OBJ_TYPE_Q */
        CPU_CHAR            *NamePtr;         /* Pointer to Message Queue Name (NUL terminated ASCII) */
        OS_PEND_LIST         PendList;        /* List of tasks waiting on message queue */
    #if OS_CFG_DBG_EN > 0u
        OS_Q                *DbgPrevPtr;
        OS_Q                *DbgNextPtr;
        CPU_CHAR            *DbgNamePtr;
    #endif
    
        OS_MSG_Q             MsgQ;            /* List of messages */
    };
    
    typedef struct os_msg_q OS_MSG_Q;
    struct  os_msg_q {                        /* OS_MSG_Q */
        OS_MSG              *InPtr;           /* Pointer to next OS_MSG to be inserted in the queue */
        OS_MSG              *OutPtr;          /* Pointer to next OS_MSG to be extracted from the queue */
        OS_MSG_QTY           NbrEntriesSize;  /* Maximum allowable number of entries in the queue */
        OS_MSG_QTY           NbrEntries;      /* Current number of entries in the queue */
        OS_MSG_QTY           NbrEntriesMax;   /* Peak number of entries in the queue */
    };
    
    typedef struct os_msg OS_MSG;
    struct  os_msg {                          /* MESSAGE CONTROL BLOCK */
        OS_MSG              *NextPtr;         /* Pointer to next message */
        void                *MsgPtr;          /* Actual message */
        OS_MSG_SIZE          MsgSize;         /* Size of the message (in # bytes) */
        CPU_TS               MsgTS;           /* Time stamp of when message was sent */
    };

![1][]

**API函数**

//创建
    void OSQCreate (OS_Q *p_q,
                    CPU_CHAR *p_name,
                    OS_MSG_QTY max_qty,
                    OS_ERR *p_err);
    
    #if OS_CFG_Q_DEL_EN > 0u
    //删除
    OS_OBJ_QTY OSQDel (OS_Q *p_q,
                       OS_OPT opt,
                       OS_ERR *p_err);
    #endif
    
    #if OS_CFG_Q_FLUSH_EN > 0u
    //清空
    OS_MSG_QTY OSQFlush (OS_Q *p_q,
                         OS_ERR *p_err);
    #endif
    
    //等待-1，接收消息
    void *OSQPend (OS_Q *p_q,
                   OS_TICK timeout,
                   OS_OPT opt,
                   OS_MSG_SIZE *p_msg_size,
                   CPU_TS *p_ts,
                   OS_ERR *p_err);
    
    #if OS_CFG_Q_PEND_ABORT_EN > 0u
    //取消等待
    OS_OBJ_QTY OSQPendAbort (OS_Q *p_q,
                             OS_OPT opt,
                             OS_ERR *p_err);
    #endif
    
    //释放+1，发送消息
    void OSQPost (OS_Q *p_q,
                  void *p_void,
                  OS_MSG_SIZE msg_size,
                  OS_OPT opt,
                  OS_ERR *p_err);

**应用举例**

#define DATAMSG_Q_NUM 4 //发送数据的消息队列的数量
    OS_Q DATA_Msg;              //定义一个消息队列，用于发送数据
    
    void start_task(void *p_arg)
    {
        OS_CRITICAL_ENTER();    //进入临界区
    
        //创建消息队列DATA_Msg
        OSQCreate ((OS_Q*       )&DATA_Msg, 
                    (CPU_CHAR*  )"DATA Msg",    
                    (OS_MSG_QTY )DATAMSG_Q_NUM, 
                    (OS_ERR*    )&err); 
    
        //创建定时器
        OSTmrCreate((OS_TMR     *)&tmr,         //定时器
                    (CPU_CHAR   *)"tmr",        //定时器名字
                    (OS_TICK     )0,            //0ms
                    (OS_TICK     )50,           //50*10=500ms
                    (OS_OPT      )OS_OPT_TMR_PERIODIC, //周期模式
                    (OS_TMR_CALLBACK_PTR)tmr_callback,//定时器回调函数
                    (void       *)0,            //参数为0
                    (OS_ERR     *)&err);        //返回的错误码
    
        //创建msgpend任务
        OSTaskCreate((OS_TCB    * )&Msgpend_TaskTCB,        
                     (CPU_CHAR  * )"msgpend task",      
                     (OS_TASK_PTR )msgpend_task,            
                     (void      * )0,                   
                     (OS_PRIO     )MSGPEND_TASK_PRIO,     
                     (CPU_STK   * )&MSGPEND_TASK_STK[0],    
                     (CPU_STK_SIZE)MSGPEND_STK_SIZE/10, 
                     (CPU_STK_SIZE)MSGPEND_STK_SIZE,        
                     (OS_MSG_QTY  )0,                   
                     (OS_TICK     )0,                   
                     (void      * )0,                   
                     (OS_OPT      )OS_OPT_TASK_STK_CHK|OS_OPT_TASK_STK_CLR,
                     (OS_ERR    * )&err);
    
        OS_CRITICAL_EXIT(); //退出临界区
    }
    
    //定时器的回调函数
    void tmr_callback(void *p_tmr,void *p_arg)
    {
        u8 *pbuf;
        static u8 msg_num;
        OS_ERR err;
    
        pbuf = mymalloc(SRAMIN,10); //申请10个字节
        if(pbuf)    //申请内存成功
        {
            msg_num++;
            sprintf((char*)pbuf,"ALIENTEK %d",msg_num);
            printf("tmr_callback: %s\r\n", pbuf);
            //发送消息
            OSQPost((OS_Q*      )&DATA_Msg,     
                    (void*      )pbuf,
                    (OS_MSG_SIZE)10,
                    (OS_OPT     )OS_OPT_POST_FIFO,
                    (OS_ERR*    )&err);
            if(err != OS_ERR_NONE)
            {
                myfree(SRAMIN,pbuf);    //释放内存
                OSTmrStop(&tmr,OS_OPT_TMR_NONE,0,&err); //停止定时器
                printf("TMR STOP!\r\n");
            }
        }   
    }
    
    //等待消息队列中的消息
    void msgpend_task(void *p_arg)
    {
        u8 *p;
        OS_MSG_SIZE size;
        OS_ERR err; 
        while(1)
        {
            //请求消息
            p=OSQPend((OS_Q*        )&DATA_Msg,   
                      (OS_TICK      )0,
                      (OS_OPT       )OS_OPT_PEND_BLOCKING,
                      (OS_MSG_SIZE* )&size, 
                      (CPU_TS*      )0,
                      (OS_ERR*      )&err);
            printf("msgpend_task: %s\r\n", p);
            myfree(SRAMIN,p);   //释放内存
            OSTimeDlyHMSM(0,0,1,0,OS_OPT_TIME_PERIODIC,&err); //延时1s
        }
    }

**实验现象**  
![1][1 1]

[1]: /images/20220602/027caf0bf7e44950a18ce54d662150e0.png
[1 1]: /images/20220602/f077c4fb0ac141b0ac28dbf358713e39.png