UCOSIII内嵌信号量

女爷i 2022-06-02 00:09 194阅读 0赞

> 不仅能够简化代码，而且比使用独立的信号量更有效

**API函数**

//等待-1
    OS_SEM_CTR OSTaskSemPend (OS_TICK timeout,
                              OS_OPT opt,
                              CPU_TS *p_ts,
                              OS_ERR *p_err);
    
    //取消等待
    CPU_BOOLEAN OSTaskSemPendAbort (OS_TCB *p_tcb,
                                    OS_OPT opt,
                                    OS_ERR *p_err);
    
    //释放+1
    OS_SEM_CTR OSTaskSemPost (OS_TCB *p_tcb,
                              OS_OPT opt,
                              OS_ERR *p_err);
    
    //设定值
    OS_SEM_CTR OSTaskSemSet (OS_TCB *p_tcb,
                             OS_SEM_CTR cnt,
                             OS_ERR *p_err);

**应用举例**

void start_task(void *p_arg)
    {
        OS_CRITICAL_ENTER();    //进入临界区
    
        //创建TASK1任务
        OSTaskCreate((OS_TCB    * )&Task1_TaskTCB,      
                     (CPU_CHAR  * )"Task1 task",        
                     (OS_TASK_PTR )task1_task,          
                     (void      * )0,                   
                     (OS_PRIO     )TASK1_TASK_PRIO,     
                     (CPU_STK   * )&TASK1_TASK_STK[0],  
                     (CPU_STK_SIZE)TASK1_STK_SIZE/10,   
                     (CPU_STK_SIZE)TASK1_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);           
    
        //创建TASK2任务
        OSTaskCreate((OS_TCB    * )&Task2_TaskTCB,      
                     (CPU_CHAR  * )"Task2 task",        
                     (OS_TASK_PTR )task2_task,          
                     (void      * )0,                   
                     (OS_PRIO     )TASK2_TASK_PRIO,     
                     (CPU_STK   * )&TASK2_TASK_STK[0],  
                     (CPU_STK_SIZE)TASK2_STK_SIZE/10,   
                     (CPU_STK_SIZE)TASK2_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
    }
    
    //任务1的任务函数
    void task1_task(void *p_arg)
    {
        OS_ERR err;
        u8 task1_str[]="First task Running!";
        while(1)
        {
            OSTaskSemPost(&Task2_TaskTCB,OS_OPT_POST_NONE,&err);    //使用系统内建信号量向任务task2发送信号量
            printf("\r\n任务1:\r\n");
            memcpy(share_resource,task1_str,sizeof(task1_str)); //向共享资源区拷贝数据
            printf("%s\r\n",share_resource);    //串口输出共享资源区数据 
            OSTimeDlyHMSM(0,0,3,0,OS_OPT_TIME_PERIODIC,&err);           //延时10ms
        }
    }
    
    //任务2的任务函数
    void task2_task(void *p_arg)
    {   
        OS_ERR err;
        u8 task2_str[]="Second task Running!";
        while(1)
        { 
            OSTaskSemPend(0,OS_OPT_PEND_BLOCKING,0,&err);       //请求任务内建的信号量
            printf("\r\n任务2:\r\n");
            memcpy(share_resource,task2_str,sizeof(task2_str)); //向共享资源区拷贝数据
            printf("%s\r\n",share_resource);    //串口输出共享资源区数据 
            OSTimeDlyHMSM(0,0,1,0,OS_OPT_TIME_PERIODIC,&err);   //延时1s
        }
    }

**实验现象**  
![1][]

[1]: /images/20220602/9a272b48da3b4440b66017edf953dbb3.png