uC/OS-II时间(OS_time)块

/*
*********************************************************************************************************
*                                                uC/OS-II
*                                          The Real-Time Kernel
*                                             TIME MANAGEMENT
*
*                          (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
*                                           All Rights Reserved
*
* File : OS_TIME.C
* By   : Jean J. Labrosse
*********************************************************************************************************
*/

#ifndef  OS_MASTER_FILE
#include "includes.h"
#endif

/*
*********************************************************************************************************
*                                DELAY TASK 'n' TICKS   (n from 0 to 65535)
*
* Description: This function is called to delay execution of the currently running task until the
*              specified number of system ticks expires(到期).  This, of course, directly equates to delaying
*              the current task for some time to expire.  No delay will result If the specified delay is
*              0.  If the specified delay is greater than 0 then, a context switch will result.
*
* Arguments  : ticks     is the time delay that the task will be suspended in number of clock 'ticks'.
*                        Note that by specifying 0, the task will not be delayed.
*
* Returns    : none
*********************************************************************************************************
*/
//延时时间
void  OSTimeDly (INT16U ticks)
{
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;
#endif    

    if (ticks > 0) {                                                      /* 0 means no delay!         */
        OS_ENTER_CRITICAL();
        //Delay current task
        if ((OSRdyTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0) {  /* Delay current task        */
            //取消当前的任务状态
            OSRdyGrp &= ~OSTCBCur->OSTCBBitY;
        }
        //延时的节拍数存到任务控制块中
        OSTCBCur->OSTCBDly = ticks;                                       /* Load ticks in TCB         */
        OS_EXIT_CRITICAL();
        //触发一次任务调度
        OS_Sched();                                                       /* Find next task to run!    */
    }
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                     DELAY TASK FOR SPECIFIED TIME
*
* Description: This function is called to delay execution of the currently running task until some time
*              expires.  This call allows you to specify the delay time in HOURS, MINUTES, SECONDS and
*              MILLISECONDS instead of ticks.
*
* Arguments  : hours     specifies the number of hours that the task will be delayed (max. is 255)
*              minutes   specifies the number of minutes (max. 59)
*              seconds   specifies the number of seconds (max. 59)
*              milli     specifies the number of milliseconds (max. 999)
*
* Returns    : OS_NO_ERR
*              OS_TIME_INVALID_MINUTES
*              OS_TIME_INVALID_SECONDS
*              OS_TIME_INVALID_MS
*              OS_TIME_ZERO_DLY
*
* Note(s)    : The resolution on the milliseconds depends on the tick rate.  For example, you can't do
*              a 10 mS delay if the ticker interrupts every 100 mS.  In this case, the delay would be
*              set to 0.  The actual delay is rounded to the nearest tick.
*********************************************************************************************************
*/
//也是延时函数
#if OS_TIME_DLY_HMSM_EN > 0
INT8U  OSTimeDlyHMSM (INT8U hours, INT8U minutes, INT8U seconds, INT16U milli)
{
    INT32U ticks;
    INT16U loops;

    if (hours > 0 || minutes > 0 || seconds > 0 || milli > 0) {
        if (minutes > 59) {
            return (OS_TIME_INVALID_MINUTES);    /* Validate arguments to be within range              */
        }
        if (seconds > 59) {
            return (OS_TIME_INVALID_SECONDS);
        }
        if (milli > 999) {
            return (OS_TIME_INVALID_MILLI);
        }
                                                 /* Compute the total number of clock ticks required.. */
                                                 /* .. (rounded to the nearest tick)                   */
        ticks = ((INT32U)hours * 3600L + (INT32U)minutes * 60L + (INT32U)seconds) * OS_TICKS_PER_SEC
              + OS_TICKS_PER_SEC * ((INT32U)milli + 500L / OS_TICKS_PER_SEC) / 1000L;
        loops = (INT16U)(ticks / 65536L);        /* Compute the integral number of 65536 tick delays   */
        ticks = ticks % 65536L;                  /* Obtain  the fractional number of ticks             */
        OSTimeDly((INT16U)ticks);
        while (loops > 0) {
            OSTimeDly(32768);
            OSTimeDly(32768);
            loops--;
        }
        return (OS_NO_ERR);
    }
    return (OS_TIME_ZERO_DLY);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                         RESUME A DELAYED TASK
*
* Description: This function is used resume a task that has been delayed through a call to either
*              OSTimeDly() or OSTimeDlyHMSM().  Note that you MUST NOT call this function to resume a
*              task that is waiting for an event with timeout.  This situation would make the task look
*              like a timeout occurred (unless you desire this effect).  Also, you cannot resume a task
*              that has called OSTimeDlyHMSM() with a combined time that exceeds 65535 clock ticks.  In
*              other words, if the clock tick runs at 100 Hz then, you will not be able to resume a
*              delayed task that called OSTimeDlyHMSM(0, 10, 55, 350) or higher.
*
*                  (10 Minutes * 60 + 55 Seconds + 0.35) * 100 ticks/second.
*
* Arguments  : prio      specifies the priority of the task to resume
*
* Returns    : OS_NO_ERR                 Task has been resumed
*              OS_PRIO_INVALID           if the priority you specify is higher that the maximum allowed
*                                        (i.e. >= OS_LOWEST_PRIO)
*              OS_TIME_NOT_DLY           Task is not waiting for time to expire
*              OS_TASK_NOT_EXIST         The desired task has not been created
*********************************************************************************************************
*/
//This function is used resume a task that has been delayed through a call to either OSTimeDly() or OSTimeDlyHMSM()
#if OS_TIME_DLY_RESUME_EN > 0
INT8U  OSTimeDlyResume (INT8U prio)
{
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;
#endif    
    OS_TCB    *ptcb;

    //判断
    if (prio >= OS_LOWEST_PRIO) {
        return (OS_PRIO_INVALID);
    }
    OS_ENTER_CRITICAL();
    ptcb = (OS_TCB *)OSTCBPrioTbl[prio];                   /* Make sure that task exist                */
    //确定任务存在
    if (ptcb != (OS_TCB *)0) {
        //See if task is delayed
        if (ptcb->OSTCBDly != 0) {                         /* See if task is delayed                   */
            //Clear the time delay      
            ptcb->OSTCBDly  = 0;                           /* Clear the time delay                     */
            // See if task is ready to run
            if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) == OS_STAT_RDY) {  /* See if task is ready to run  */
                OSRdyGrp               |= ptcb->OSTCBBitY;             /* Make task ready to run       */
                OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
                OS_EXIT_CRITICAL();
                //task sched
                OS_Sched();                                /* See if this is new highest priority      */
            } else {
                OS_EXIT_CRITICAL();                        /* Task may be suspended                    */
            }
            return (OS_NO_ERR);
        } else {
            OS_EXIT_CRITICAL();
            return (OS_TIME_NOT_DLY);                      /* Indicate that task was not delayed       */
        }
    }
    OS_EXIT_CRITICAL();
    return (OS_TASK_NOT_EXIST);                            /* The task does not exist                  */
}
#endif    
/*$PAGE*/
/*
*********************************************************************************************************
*                                         GET CURRENT SYSTEM TIME
*
* Description: This function is used by your application to obtain the current value of the 32-bit
*              counter which keeps track of the number of clock ticks.
*
* Arguments  : none
*
* Returns    : The current value of OSTime
*********************************************************************************************************
*/

#if OS_TIME_GET_SET_EN > 0
INT32U  OSTimeGet (void)
{
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;
#endif    
    INT32U     ticks;

    OS_ENTER_CRITICAL();
    ticks = OSTime;        //The current value of OSTime
    OS_EXIT_CRITICAL();
    return (ticks);
}
#endif    

/*
*********************************************************************************************************
*                                            SET SYSTEM CLOCK
*
* Description: This function sets the 32-bit counter which keeps track of the number of clock ticks.
*
* Arguments  : ticks      specifies the new value that OSTime needs to take.
*
* Returns    : none
*********************************************************************************************************
*/

#if OS_TIME_GET_SET_EN > 0
void  OSTimeSet (INT32U ticks)
{
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;
#endif    

    OS_ENTER_CRITICAL();
    OSTime = ticks;
    OS_EXIT_CRITICAL();
}
#endif