求助，原子ucosIII例程互斥信号的系统进程

wuxxxxx炫 · 发表于 2018-1-26 17:00:16

本帖最后由 wuxxxxx炫于 2018-1-26 17:05 编辑

//任务优先级
#define HIGH_TASK_PRIO                      7
//任务堆栈大小
#define HIGH_STK_SIZE                      128
//任务控制块
OS_TCB High_TaskTCB;
//任务堆栈
CPU_STK HIGH_TASK_STK[HIGH_STK_SIZE];
void high_task(void *p_arg);

//任务优先级
#define MIDDLE_TASK_PRIO             8
//任务堆栈大小
#define MIDDLE_STK_SIZE                128
//任务控制块
OS_TCB Middle_TaskTCB;
//任务堆栈
CPU_STK MIDDLE_TASK_STK[MIDDLE_STK_SIZE];
void middle_task(void *p_arg);

//任务优先级
#define LOW_TASK_PRIO                      9
//任务堆栈大小
#define LOW_STK_SIZE                      128
//任务控制块
OS_TCB Low_TaskTCB;
//任务堆栈
CPU_STK LOW_TASK_STK[LOW_STK_SIZE];
void low_task(void *p_arg);

//高优先级任务的任务函数
void high_task(void *p_arg)
{
      u8 num;
      OS_ERR err;

      CPU_SR_ALLOC();
      POINT_COLOR = BLACK;
      OS_CRITICAL_ENTER();
      LCD_DrawRectangle(5,110,115,314);       //画一个矩形
      LCD_DrawLine(5,130,115,130);             //画线
      POINT_COLOR = BLUE;
      LCD_ShowString(6,111,110,16,16,"High Task");
      OS_CRITICAL_EXIT();
      while(1)
      {
            OSTimeDlyHMSM(0,0,0,500,OS_OPT_TIME_PERIODIC,&err);                //延时500ms
            num++;
            printf("high task Pend Mutex\r\n");
            OSMutexPend (&TEST_MUTEX,0,OS_OPT_PEND_BLOCKING,0,&err);       //请求互斥信号量
            printf("high task Running!\r\n");
            LCD_Fill(6,131,114,313,lcd_discolor[num%14]);                               //填充区域
            LED1 = ~LED1;
            OSMutexPost(&TEST_MUTEX,OS_OPT_POST_NONE,&err);                               //释放互斥信号量
            printf("high task Post Mutex\r\n");
            OSTimeDlyHMSM(0,0,0,500,OS_OPT_TIME_PERIODIC,&err);                //延时500ms
      }
}

//中等优先级任务的任务函数
void middle_task(void *p_arg)
{
      u8 num;
      OS_ERR err;
      CPU_SR_ALLOC();

      POINT_COLOR = BLACK;
      OS_CRITICAL_ENTER();
      LCD_DrawRectangle(125,110,234,314); //画一个矩形
      LCD_DrawLine(125,130,234,130);             //画线
      POINT_COLOR = BLUE;
      LCD_ShowString(126,111,110,16,16,"Middle Task");
      OS_CRITICAL_EXIT();
      while(1)
      {
            num++;
            printf("middle task Running!\r\n");
            LCD_Fill(126,131,233,313,lcd_discolor[13-num%14]); //填充区域
            LED0 = ~LED0;
            OSTimeDlyHMSM(0,0,1,0,OS_OPT_TIME_PERIODIC,&err); //延时1s
      }
}

//低优先级任务的任务函数
void low_task(void *p_arg)
{
      static u32 times;
      OS_ERR err;
      while(1)
      {
            OSMutexPend (&TEST_MUTEX,0,OS_OPT_PEND_BLOCKING,0,&err);//请求互斥信号量
            printf("low task Running!\r\n");
            for(times=0;times<10000000;times++)
            {
                     OSSched();                                                                                     //发起任务调度
            }
            OSMutexPost(&TEST_MUTEX,OS_OPT_POST_NONE,&err);                      //释放互斥信号量
            OSTimeDlyHMSM(0,0,1,0,OS_OPT_TIME_PERIODIC,&err);          //延时1s
      }
}

代码在上面，阉割了与问题无关的部分

高优先级获得互斥信号运行后，根据优先级，运行中等优先级，为什么之后运行的又是高优先级任务，不明白！