Teach you how to use UCOS

Ucos Operating system learning

 

Real-time operating system ：

Task switching , Dispatch

Fractional operating system

 

Inalienable kernel

Ucosii The source code of embedded real-time operating system is divided into three parts ： Hardware independent kernel code , Processor related migration code and user profiles .

 

Ucos Most support 64 A mission , The priorities correspond to 0~63, among 0 Is the highest priority , System reservation 4 Top priority tasks , and 4 The lowest priority task , Tasks available to all users 56 individual

1. Set up tasks

a)      OSTaskCReat()/OStaskCreat(

    i.           OStaskCreat(void(*task),void pdata ,OS_STK * post,INTU prio)

        1.      Task: Pointer to the task code

        2.      Pdata: When the task starts to execute , Pointer to the parameter passed to the task

        3.      Post: The top pointer to the stack assigned to the task

        4.      Prior： Assign priority to tasks

2,  Task stack

a)      OS_STK()

        i.            Each task has its own stack , The stack must be declared as OS_STK type , And continuous memory space .

            ii.            It can be allocated statically and dynamically

3,  Stack check

        a)      OSTaskStkChk()

            i.  Sometimes the determining task is to know the size of the stack space , This function avoids allocating too much space

4.    Delete task OSTask()

       a.    It means that the task enters the sleep state , It doesn't mean that the code is deleted , Just no longer ucos call . Be careful ： Before deleting a task, make sure that it is not an idle task

5.    Request to delete task OSTaskDelreq()

        a. Sometimes a task will occupy some memory or semaphore resources . At this time , Suppose another task tries to delete a task , These occupied resources will be lost because they have not been released . under these circumstances , The task needs to be released after use , Then delete it yourself .

6.    Change the priority of the task OSTaskChangePrio()

        a. When creating a task , Need to use OSTaskCreate() Function to specify the priority of the task , In most cases, there is no need to change the task priority when the system is running , But if it changes ,OSTaskChangePrio() It can be done .

          b.void OSTaskChangePrio(OS_TCB *p_tcp,OS_PRIO prio_new,OS_ERR *err);

                i.p_tcp : Need to change priority tasks . If you pass in NULL Refers to the priority of the current task

                ii：p_new: New priorities , The value cannot be greater than or equal to OS_CFG_PRIO_MAX-1de The number , Not for 0.

                iii: Store the error return code of this function .

7.    OS_FlagDel()

        a. Used to delete time stamp Group . Pay attention to , It is possible to delete multiple tasks at the same time, all of which depend on the time stamp Group

        b.OS_OBJ_QTY OSFlagDel(OS_FLAG_GPR *p_grp,OS_OPT opt,OE_ERR *p_err), Task enable light up OS_CFG_FLAG_EN and

OS_CFG_FLAG_EDL_EN

                i.p_grp Pointer to the flag group to delete the event

                ii.opt    Specify the flag to delete the event group

                iii.err    Erroneous return