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Task Management API Changes

Task Management API Changes

Mar 23, 2021

The table below shows the difference in API for task-management services.

Task Management API

µC/OS-II (os_task.c)

µC/OS-III (os_task.c)

Note

INT8U OSTaskChangePrio( INT8U oldprio, INT8U newprio);

void OSTaskChangePrio( OS_TCB *p_tcb, OS_PRIO prio, OS_ERR *p_err);

(1)

INT8U OSTaskCreate( void (*task)(void *p_arg), void *p_arg, OS_STK *ptos, INT8U prio);

void OSTaskCreate( OS_TCB *p_tcb, CPU_CHAR *p_name, OS_TASK_PTR *p_task, void *p_arg, OS_PRIO prio, CPU_STK *p_stk_base, CPU_STK_SIZE stk_limit, CPU_STK_SIZE stk_size, OS_MSG_QTY q_size, OS_TICK time_quanta, void *p_ext, OS_OPT opt, OS_ERR *p_err);

(2)  

INT8U OSTaskCreateExt( void (*task)(void *p_arg), void *p_arg, OS_STK *ptos, INT8U prio, INT16U id, OS_STK *pbos, INT32U stk_size, void *pext, INT16U opt);

void OSTaskCreate( OS_TCB *p_tcb, CPU_CHAR *p_name, OS_TASK_PTR *p_task, void *p_arg, OS_PRIO prio, CPU_STK *p_stk_base, CPU_STK_SIZE stk_limit, CPU_STK_SIZE stk_size, OS_MSG_QTY q_size, OS_TICK time_quanta, void *p_ext, OS_OPT opt, OS_ERR *p_err);

(2)

INT8U OSTaskDel( INT8U prio);

void OSTaskDel( OS_TCB *p_tcb, OS_ERR *p_err);

INT8U OSTaskDelReq( INT8U prio);

INT8U OSTaskNameGet( INT8U prio, INT8U **pname, INT8U *perr);

void OSTaskNameSet( INT8U prio, INT8U *pname, INT8U *perr);

(3)

OS_MSG_QTY OSTaskQFlush( OS_TCB *p_tcb, OS_ERR *p_err);

(4)

void * OSTaskQPend( OS_TICK timeout, OS_OPT opt, OS_MSG_SIZE *p_msg_size, CPU_TS *p_ts, OS_ERR *p_err);

(4)

CPU_BOOLEAN OSTaskQPendAbort( OS_TCB *p_tcb, OS_OPT opt, OS_ERR *p_err);

(4)

void OSTaskQPost( OS_TCB *p_tcb, void *p_void, OS_MSG_SIZE msg_size, OS_OPT opt, OS_ERR *p_err);

(4)

INT32U OSTaskRegGet( INT8U prio, INT8U id, INT8U *perr);

OS_REG OSTaskRegGet( OS_TCB *p_tcb, OS_REG_ID id, OS_ERR *p_err);

void OSTaskRegSet( INT8U prio, INT8U id, INT32U value, INT8U *perr);

void OSTaskRegGet( OS_TCB *p_tcb, OS_REG_ID id, OS_REG value, OS_ERR *p_err);

INT8U OSTaskResume( INT8U prio);

void OSTaskResume( OS_TCB *p_tcb, OS_ERR *p_err);

OS_SEM_CTR OSTaskSemPend( OS_TICK timeout, OS_OPT opt, CPU_TS *p_ts, OS_ERR *p_err);

(5)

CPU_BOOLEAN OSTaskSemPendAbort( OS_TCB *p_tcb, OS_OPT opt, OS_ERR *p_err);

(5)

CPU_BOOLEAN OSTaskSemPendAbort( OS_TCB *p_tcb, OS_OPT opt, OS_ERR *p_err);

(5)

OS_SEM_CTR OSTaskSemPost( OS_TCB *p_tcb, OS_OPT opt, OS_ERR *p_err);

(5)

OS_SEM_CTR OSTaskSemSet( OS_TCB *p_tcb, OS_SEM_CTR cnt, OS_ERR *p_err);

(5)

INT8U OSTaskSuspend( INT8U prio);

void OSTaskSuspend( OS_TCB *p_tcb, OS_ERR *p_err);

INT8U OSTaskStkChk( INT8U prio, OS_STK_DATA *p_stk_data);

void OSTaskStkChk( OS_TCB *p_tcb, CPU_STK_SIZE *p_free, CPU_STK_SIZE *p_used, OS_ERR *p_err);

(6)

void OSTaskTimeQuantaSet( OS_TCB *p_tcb, OS_TICK time_quanta, OS_ERR *p_err);

(7)

INT8U OSTaskQuery( INT8U prio, OS_TCB *p_task_data);

(8)

 

(1) In µC/OS-II, each task must have a unique priority. The priority of a task can be changed at run-time, however it can only be changed to an unused priority. This is generally not a problem since µC/OS-II supports up to 255 different priority levels and is rare for an application to require all levels. Since µC/OS-III supports an unlimited number of tasks at each priority, the user can change the priority of a task to any available level.

(2) µC/OS-II provides two functions to create a task: OSTaskCreate() and OSTaskCreateExt(). OSTaskCreateExt() is recommended since it offers more flexibility. In µC/OS-III, only one API is used to create a task, OSTaskCreate(), which offers similar features to OSTaskCreateExt() and provides additional ones.

(3) µC/OS-III does not need an OSTaskNameSet() since an ASCII name for the task is passed as an argument to OSTaskCreate().

(4) µC/OS-III allows tasks or ISRs to send messages directly to a task instead of having to pass through a mailbox or a message queue as does µC/OS-II.

(5) µC/OS-III allows tasks or ISRs to directly signal a task instead of having to pass through a semaphore as does µC/OS-II.

(6) In µC/OS-II, the user must allocate storage for a special data structure called OS_STK_DATA, which is used to place the result of a stack check of a task. This data structure contains only two fields: .OSFree and .OSUsed. In µC/OS-III, it is required that the caller pass pointers to destination variables where those values will be placed.

(7) µC/OS-III allows users to specify the time quanta of each task on a per-task basis. This is available since µC/OS-III supports multiple tasks at the same priority, and allows for round robin scheduling. The time quanta for a task is specified when the task is created, but it can be changed by the API at run time.

(8) µC/OS-III does not provide query services as they were rarely used.