...
This field contains a pointer to a user-definable data area used to extend the TCB as needed. This pointer is provided as an argument passed in OSTaskCreate(). This pointer is easily accessible from assembly language since it always follows the .StkPtr. .ExtPtr can be used to add storage for saving the context of a FPU (Floating-Point Unit) if the processor you are using has a FPU.
.StkLimitPtr
...
NamePtr
This pointer allows a name (an ASCII string) to be assigned to each task. Having a name is useful when debugging, since it is user friendly compared to displaying the address of the OS_TCB. Storage for the ASCII string is assumed to be in user space, either in code memory (ASCII string declared as a const) or in RAM.
.StkLimitPtr
The field contains a pointer to a location in the task’s stack to set a watermark limit for stack growth and is determined from the value of the “stk_limit” argument passed to OSTaskCreate(). Some processors have special registers that automatically check the value of the stack pointer at run-time to ensure that the stack does not overflow. .StkLimitPtr may be used to set this register during a context switch. Alternatively, if the processor does not have such a register, this can be “simulated” in software. However, this is not as reliable as a hardware solution. If this feature is not used then you can set the value of “stk_limit” can be set to 0 when calling OSTaskCreate(). See also Detecting Task Stack Overflows).
...
This pointer points to one of two tick lists: either the list of tasks delayed waiting for time to expire (OSTickListDly) or tasks pending on an object with a timeout (OSTickListTimeout). This field is used to easily remove the OS_TCB from the list.
.NamePtr
This pointer allows a name (an ASCII string) to be assigned to each task. Having a name is useful when debugging, since it is user friendly compared to displaying the address of the OS_TCB. Storage for the ASCII string is assumed to be in user space, either in code memory (ASCII string declared as a const) or in RAMthe OS_TCB from the list.
.StkBasePtr
This field points to the base address of the task’s stack. The stack base is typically the lowest address in memory where the stack for the task resides. A task stack is declared as follows:
...
This field contains the value of the argument that is passed to the task when the task starts. As previously mentioned, a task is declared as shown below and this field contains the value of p_arg.
void MyTask (void *p_arg);
.PendDataTblPtr
µC/OS-III allows the task to pend on any number of semaphores or message queues simultaneously. This pointer points to a table containing information about the pended objects. This is value of p_arg.
void MyTask (void *p_arg);
.PendNextPtr and .PendPrevPtr
These two pointers are used to doubly link the OS_TCB in a wait list for a kernel object such as a semaphore, event flag group, mutex or message queue. This is further described in Chapter 10, “Pend Lists”.
.PendObjPtr
Is a pointer to the kernel object pended on. This is further described in Chapter 10, “Pend Lists”..
This field indicates what the task is pending on and contains one of the following values declared in os.h:
OS_TASK_PEND_ON_NOTHING
OS_TASK_PEND_ON_FLAG
OS_TASK_PEND_ON_TASK_Q
OS_TASK_PEND_ON_MULTIMUTEX
OS_TASK_PEND_ON_MUTEXQ
OS_TASK_PEND_ON_QSEM
OS_TASK_PEND_ON_TASK_SEM
OS_TASK_PEND_ON_TASKCOND_SEM VAR
.PendStatus
This field indicates the outcome of a pend and contains one of the values declared in os.h:
...
This field is used to store a “time stamp” of when an event that the task was waiting on occurred. When the task resumes execution, this time stamp is returned to the caller.
.SemID
This field is used by third-party tools such TraceAlyzer by Percepio.
.SemCtr
This field contains a semaphore counter associated with the task. Each task has its own built-in semaphore. An ISR or another task can signal a task using this semaphore. .SemCtr is therefore used to keep track of how many times the task is signaled. .SemCtr is used by OSTaskSem???() services.
...
You can also ‘add’ OS_OPT_PEND_FLAG_CONSUME and either OS_OPT_PEND_BLOCKING or OS_OPT_PEND_NON_BLOCKING to the above options.
.MonData
Monitor data associated with a task.
.SuspendCtr
This field is used by OSTaskSuspend() and OSTaskResume() to keep track of how many times a task is suspended. Task suspension can be nested. When .SuspendCtr is 0, all suspensions are removed. This field only exists in a TCB if task suspension is enabled at compile time (OS_CFG_TASK_SUSPEND_EN is set to DEF_ENABLED in os_cfg.h).
...
This field contains a pointer to the name of the object that the task is pending on when the task is pending on either an event flag group, a semaphore, a mutual exclusion semaphore or a message queue. This information is quite useful during debugging and thus, this field is only present if if OS_CFG_DBG_EN is is set to to DEF_ENABLED in in os_cfg.h.
.TaskID
This field is used by third-party tools such as TraceAlyzer by Percepio.