UCOSIII内嵌信号量

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("
任务1:
");
        memcpy(share_resource,task1_str,sizeof(task1_str)); //向共享资源区拷贝数据
        printf("%s
",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("
任务2:
");
        memcpy(share_resource,task2_str,sizeof(task2_str)); //向共享资源区拷贝数据
        printf("%s
",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