Summary of Commonly Used uC/OS-II Functions and Data Structures

Data Structures

typedef struct {
    INT8U    OSEventType;                    	/* Type of event control block (see OS_EVENT_TYPE_???)     */
    INT8U    OSEventGrp;                     	/* Group corresponding to tasks waiting for event to occur */
    INT16U   OSEventCnt;                     	/* Semaphore Count (not used if other EVENT type)          */
    void    *OSEventPtr;                     	/* Pointer to message or queue structure                   */
    INT8U    OSEventTbl[OS_EVENT_TBL_SIZE];  	/* List of tasks waiting for event to occur                */
    char     OSEventName[OS_EVENT_NAME_SIZE]; 	/* Compile time directive currently has OS_EVENT_NAME_SIZE = 32 */
} OS_EVENT;


#define  OS_EVENT_TYPE_UNUSED      0		/* All possible values for OSEventType in OS_EVENT struct */
#define  OS_EVENT_TYPE_MBOX        1
#define  OS_EVENT_TYPE_Q           2
#define  OS_EVENT_TYPE_SEM         3
#define  OS_EVENT_TYPE_MUTEX       4
#define  OS_EVENT_TYPE_FLAG        5

typedef unsigned short OS_STK;                   /* Each stack entry is 16-bit wide                    */

typedef struct {
    INT32U  OSFree;                    /* Number of free bytes on the stack for a specific task */
    INT32U  OSUsed;                    /* Number of bytes used on the stack for a specific task*/
} OS_STK_DATA;

typedef struct os_tcb{
	OS_STK		*OSTCBStkPtr;		//Stack Pointer
	void		*OSTCBExtPtr;		//TCB extension pointer
	OS_STK		*OSTCBStkBottom;	//Ptr to bottom of stack
	INT32U		OSTCBStkSize;		//Size of task stack (#elements)
	INT16U		OSTCPOpt;		//Task options
	struct os_tcb	*OSTCBNext;		//Pointer to next TCB
	struct os_tcb	*OSTCBPrev;		//Pointer to previous TCB
	OS_EVENT	*OSTCBEventPtr;		//Pointer to ECB
	void		*OSTCBMsg;		//Message received
	OS_FLAG_NODE	*OSTCBFlagNode;		//Pointer to event flag node
	OS_FLAGS	OSTCBFlagsRdy		//Event flags that made task ready
	INT16U		OSTCBDly;		//Nbr ticks to delay task or, timeout
	INT8U		OSTCBStat;		//Task Status
	INT8U		OSTCBPrio;		//Task Priority (0 = highest)
	INT8U		OSTCBX;
	INT8U		OSTCBY;
	INT8U		OSTCBBitX;
	INT8U		OSTCBBitY;
	BOOLEAN		OSTCBDelReq;		//Flag to tell task to delete itself
}OS_TCB;

Global Variables

OS_EXT  INT8S             OSCPUUsage;               /* Percentage of CPU used                          */

Vector Table Entries

*((int *)0x80) = (int)OSCtxSw;	/* set up vector to Context Switch (TRAP #0) */

Initialization Functions

begin (void)    			/* SYSTEM ENTRY POINT */
{

    *((int *)0x80) = (int)OSCtxSw;	/* set up vector to Context Switch (TRAP #0) */
    OSInit();
    .
    .	
    OSStart();  			  /* away we go ! */
}

begin (void)    			/* SYSTEM ENTRY POINT */
{

    *((int *)0x80) = (int)OSCtxSw;	/* set up vector to Context Switch (TRAP #0) */
    OSInit();
    .
    .	
    OSStart();  			  /* away we go ! */
}

begin (void)    			/* SYSTEM ENTRY POINT */
{
    *((int *)0x80) = (int)OSCtxSw;	/* set up vector to Context Switch (TRAP #0) */
    OSInit();
    TaskCreate("StartTask",StartTask,StartTask_ID);
    OSStart();  			  /* away we go ! */
}

void StartTask(void *data)
{
    ScopeInit();		/* Initialize oscilloscope triggering routine */
    TickInit();		/* Start OS ticker,  see os/os_cpu_a.s */
    OSStatInit();		/* Initialize statistics task */
    OSTaskCreateExt(...);	/* all clear to call tasks now */
    OSTaskCreateExt(...);	
    .
    .
    .
    OSTaskDel(OS_PRIO_SELF);	/* This task only runs once */
}

Task Functions

	#define TASK_OPT	OS_TASK_OPT_STK_CHK + OS_TASK_OPT_STK_CLR

	void TaskCreate(char *TaskDesc, void *TaskFunc, INT8U TaskID)
	{
    		INT8U err;
    		err=OSTaskCreateExt(TaskFunc,
                        (void *)0,
                        &TaskStack[TaskID][TASK_STACK_SIZE-1],
                        TaskID+5,
                        TaskID,
                        &TaskStack[TaskID][0],
                        TASK_STACK_SIZE,
                        &TaskData[TaskID],
                        TASK_OPT);
    		if (!err)
        		strcpy(TaskData[TaskID].TaskName, TaskDesc);
    		else
        		disp_err(err);
	}

	void StartTask(void *data)
	{
    		ScopeInit();		/* Initialize oscilloscope triggering routine */
    		TickInit();		/* Start OS ticker,  see src/uC/os_cpu_a.s */
    		OSStatInit();		/* Initialize statistics task */
    		LEDQueue = OSQCreate (LEDQueueTbl, 10);
		.
		.
		.
    		OSTaskDel(OS_PRIO_SELF);	/* We don't want the Start ask to run more than once */
	}

    	OS_STK_DATA   StackData;    	
	INT8U         err;

	err = OSTaskStkChk(OS_PRIO_SELF,&StackData);

    	OS_TCB    task_data;    	
	INT8U     err;

	err = OSTaskQuery(OS_PRIO_SELF,&task_data);

Queue Functions

	begin (void)
	{
    		*((int *)0x80) = (int)OSCtxSw;	/* set up vector to Context Switch (TRAP #0) */
    		OSInit();
    		TaskCreate("StartTask",StartTask,StartTask_ID);
    		OSStart();
	}

	void StartTask(void *data)
	{
    		ScopeInit();
    		TickInit();
    		.
    		.
    		TxQueueA = OSQCreate (TxQueueTblA, FIFO_SIZE);
    		TxQueueB = OSQCreate (TxQueueTblB, FIFO_SIZE);
    		.  
    		.
    		OSTaskDel(OS_PRIO_SELF);	/* This task only runs once */
	}

	LedQueueData = *(LED_DATA *)OSQPend(LEDQueue, 0, &err);  /* this will block until a queue entry is available */
	if (err)
   		disp_err(err);

	void LedBufferPost(char num, char state)
	{
    		INT8U err; 
    		if (LedBufferIndex >=10)
        		LedBufferIndex=0;
    		LedBuffer[LedBufferIndex].LedNum = num;
    		LedBuffer[LedBufferIndex].State = state;
    		err = OSQPost(LEDQueue, (void *)&LedBuffer[LedBufferIndex++]);
	}

Semaphore Functions

	OS_EVENT *TxSemA, *TxSemB, *TxBufferLock;

	void StartTask(void *data)
	{
    		ScopeInit();
    		TickInit();
    		TxSemA = OSSemCreate(0);
    		TxSemB = OSSemCreate(0);
    		TxBufferLock =  OSSemCreate(1);
    		.
		.
    		DuartInit();
    		OSTaskDel(OS_PRIO_SELF);	/* This task only runs once */
	}

	void TxTask1 (void *data)	/* send the uppercase alphabet to TxA */

	{
    		char byte;
    		char err;
    		while(1)
    		{
    			byte=0x41;
        		OSSemPend(TxBufferLock, 0, &err);
        		while (byte <= 0x5A)
            			TxBufferPost(0, byte++);
        		TxBufferPost(0, CR);
        		TxBufferPost(0, LF);
        		OSSemPost(TxBufferLock);
        		OSTimeDly(64);
    		}
	}

	void TxTask1 (void *data)	/* send the uppercase alphabet to TxA */

	{
    		char byte;
    		char err;
    		while(1)
    		{
    			byte=0x41;
        		OSSemPend(TxBufferLock, 0, &err);
        		while (byte <= 0x5A)
            			TxBufferPost(0, byte++);
        		TxBufferPost(0, CR);
        		TxBufferPost(0, LF);
        		OSSemPost(TxBufferLock);
        		OSTimeDly(64);
    		}
	}

Time Functions

	while(1)
     	{
       		/* One second = 64 ticks*/
        	OSTimeDly(64);
     	}

	while(1)
     	{
        	LEDValue = *(char *)OSQPend(LEDQueue, 0, &err);
        	if (err)
            		disp_err(err);
        	led_current |= LEDValue;
        	*LED = led_current;
		OSTimeDlyHMSM(0,0,0,50);
        	led_current &= ~LEDValue;
        	*LED = led_current;
     }

• Refer to the source code as indicated in the Location: field in the tables above for additional comments.

• Main reference and source for this document is:
  Jean J. Labrosse, MicroC/OS-II - The Real-Time Kernel, 2nd ed., (CMP Books, 2002), ISBN 1-57820-103-9