BLE 協議棧之RTC時鐘

BLE協議棧裏有已經封裝好的RTC時鐘，時鐘源可以是外部晶體振盪時鐘也可以是內部RC時鐘。

The32-kHzXOSC is designed to operate at 32.768kHz and provide a stable clock signal for systems requiring time accuracy.The 32-kHz RCOS runs at32.753kHz when  calibrated.

外部晶振更加精準一些！

主要的函數在OSAL_ClockBLE.c中;

void osalTimeUpdate( void )
{
  uint16 tmp;      //爲暫存變量，用於臨時存放時間值
  uint16 ticks625us;  //用於存放timer2的溢出次數，每次溢出爲625us，也就是說ticks625us代表了625us的個數
  uint16 elapsedMSec = 0;//也是用來存放時間值的，只是它存放的值是上一次操作所保留下來的值，它最終存放的是時間的ms值


  // Get the free-running count of 625us timer ticks
  tmp = ll_McuPrecisionCount();//這個函數就是用來讀取timer2溢出次數的，溢出次數存放在T2MOVF2（[23:16]）,T2MOVF2([15:8]), T2MOVF0([7:0]), 一共有24bit

  if ( tmp != previousLLTimerTick )//判斷時間是否有變化（正常情況下，隨着程序的運行，tmp 這個值一直增大（16-bit））
  {
    // Calculate the elapsed ticks of the free-running timer.
    ticks625us = tmp - previousLLTimerTick;//當前的時間值減去上一次的值，也就是代碼再一次運行到這裏所消耗的時間（注意單位爲625us）

    // Store the LL Timer tick count for the next time through this function.
    previousLLTimerTick = tmp;//將當前值存儲起來，爲程序下一次運行到這裏作準備
  /*
  下面紅色部分的代碼，都只是實現了一個功能，就是將ticks625us個625us 轉換成 elapsedMSec 個ms（ms的整數部分）和remUsTicks 個us（ms的小數部分），“ *5 / 8” 等價於 “ *625 / 1000”（分子分母同時擴大40倍），同理“ *5 % 8” 等價於 “*625 % 1000”  至於MAXCALCTICKS ，程序中有一下兩段註釋，可以幫助我們理解
  // (MAXCALCTICKS * 5) + (max remainder) must be <= (uint16 max),
  // so: (13105 * 5) + 7 <= 65535
  #define MAXCALCTICKS  ((uint16)(13105))

  */


    /* It is necessary to loop to convert the usecs to msecs in increments so as
     * not to overflow the 16-bit variables.
     */
    while ( ticks625us > MAXCALCTICKS )//這個while是對溢出的操作
    {
      ticks625us -= MAXCALCTICKS;
      elapsedMSec += MAXCALCTICKS * 5 / 8;
      remUsTicks += MAXCALCTICKS * 5 % 8;
    }

    // update converted number with remaining ticks from loop and the
    // accumulated remainder from loop
    tmp = (ticks625us * 5) + remUsTicks;

    // Convert the 625 us ticks into milliseconds and a remainder
    elapsedMSec += tmp / 8;
    remUsTicks = tmp % 8;

    // Update OSAL Clock and Timers
    if ( elapsedMSec )//判斷時間是否到了1ms，如果等於或者超過1ms（elapsedMSec  >= 1），則需要輪詢任務列表
    {
      osalClockUpdate( elapsedMSec );//更新osal操作系統的系統時間
      osalTimerUpdate( elapsedMSec );//這個函數和任務的輪詢調度有關，即和timeout有關
    }
  }
}

當然還有設置時間函數（UTCTime是從2000年1月1日00:00：00到至今的秒數）

/*********************************************************************
 * @fn      osal_setClock
 *
 * @brief   Set the new time.  This will only set the seconds portion
 *          of time and doesn't change the factional second counter.
 *
 * @param   newTime - number of seconds since 0 hrs, 0 minutes,
 *                    0 seconds, on the 1st of January 2000 UTC
 *
 * @return  none
 */
void osal_setClock( UTCTime newTime )
{
  OSAL_timeSeconds = newTime;
}

獲得當前時間函數：

/*********************************************************************
 * @fn      osal_getClock
 *
 * @brief   Gets the current time.  This will only return the seconds
 *          portion of time and doesn't include the factional second
 *          counter.
 *
 * @param   none
 *
 * @return  number of seconds since 0 hrs, 0 minutes, 0 seconds,
 *          on the 1st of January 2000 UTC
 */
UTCTime osal_getClock( void )
{
  return ( OSAL_timeSeconds );
}

 

 

將秒數轉換爲年月日時分秒格式儲存在結構體UTCTimeStruct（定義在OSAL_Clock.h）中

/*********************************************************************
 * @fn      osal_ConvertUTCTime
 *
 * @brief   Converts UTCTime to UTCTimeStruct
 *
 * @param   tm - pointer to breakdown struct
 *
 * @param   secTime - number of seconds since 0 hrs, 0 minutes,
 *          0 seconds, on the 1st of January 2000 UTC
 *
 * @return  none
 */
void osal_ConvertUTCTime( UTCTimeStruct *tm, UTCTime secTime )
{
  // calculate the time less than a day - hours, minutes, seconds
  {
    uint32 day = secTime % DAY;
    tm->seconds = day % 60UL;
    tm->minutes = (day % 3600UL) / 60UL;
    tm->hour = day / 3600UL;
  }

  // Fill in the calendar - day, month, year
  {
    uint16 numDays = secTime / DAY;
    tm->year = BEGYEAR;
    while ( numDays >= YearLength( tm->year ) )
    {
      numDays -= YearLength( tm->year );
      tm->year++;
    }

    tm->month = 0;
    while ( numDays >= monthLength( IsLeapYear( tm->year ), tm->month ) )
    {
      numDays -= monthLength( IsLeapYear( tm->year ), tm->month );
      tm->month++;
    }

    tm->day = numDays;
  }
}

 

 

校準時間時將年月日時分秒格式轉換爲秒的函數;

/*********************************************************************
 * @fn      osal_ConvertUTCSecs
 *
 * @brief   Converts a UTCTimeStruct to UTCTime
 *
 * @param   tm - pointer to provided struct
 *
 * @return  number of seconds since 00:00:00 on 01/01/2000 (UTC)
 */
UTCTime osal_ConvertUTCSecs( UTCTimeStruct *tm )
{
  uint32 seconds;

  /* Seconds for the partial day */
  seconds = (((tm->hour * 60UL) + tm->minutes) * 60UL) + tm->seconds;

  /* Account for previous complete days */
  {
    /* Start with complete days in current month */
    uint16 days = tm->day;

    /* Next, complete months in current year */
    {
      int8 month = tm->month;
      while ( --month >= 0 )
      {
        days += monthLength( IsLeapYear( tm->year ), month );
      }
    }

    /* Next, complete years before current year */
    {
      uint16 year = tm->year;
      while ( --year >= BEGYEAR )
      {
        days += YearLength( year );
      }
    }

    /* Add total seconds before partial day */
    seconds += (days * DAY);
  }

  return ( seconds );
}

example:

har tempbuf[10]={0};
 UTCTimeStruct *Ti;

 osalTimeUpdate();
 osal_ConvertUTCTime(Ti,osal_getClock());
  tempbuf[0]=(Ti->hour)/10+'0';
 tempbuf[1]=(Ti->hour)%10+'0';
 tempbuf[2]=(Ti->minutes)/10+'0';
 tempbuf[3]=(Ti->minutes)%10+'0';
 tempbuf[4]=(Ti->seconds)/10+'0';
 tempbuf[5]=(Ti->seconds)%10+'0';
 Uart0Send_String(tempbuf,10);// 將時分秒在串口打印