APP_TIMER fast

Question

MCU : NordicSemi nRF51822-QFAC (Using custom board)

SDK Version : 6.1

Softdevice : S110 7.1

Using MDK ARM v4.6

Hi, I want to create a RTC calendar using APP_TIMER, but The time is running FAST。

One day, the time read “9:52” ，when the current real time is “9:40”,

A few days later, the time read “10:03”, when the current real time is “9:47”.

<code>#define APP_TIMER_PRESCALER         0   </code>


 
void gRtcAppTimerSecondHandle(void * p_context)
{
    SoftWareRtcHal *pRTC = (SoftWareRtcHal *)p_context;
    pRTC->mSecondCount++;
    if(pRTC->mSecondIrq != NULL)
    {
        pRTC->mSecondIrq(NULL); 
    }
    if((pRTC->mMinuteIrq != NULL) &&
        (pRTC->mSecondCount % 60 == 0))
    {
        pRTC->mMinuteIrq(NULL);
   }
   if((pRTC->mHourIrq != NULL) &&
        (pRTC->mSecondCount % 3600 == 0))
   {
        pRTC->mHourIrq(NULL);
   }
   //TRACE_INFO1("*");
    
}

void gRtcGetDate(SoftWareRtcInterface *RtcInterface, uint32_t RTC_Format,RTC_DateTypeDef* RTC_DateStruct) {
    SoftWareRtcHal *pRTC;
    RTC_TimeTypeDef mRtcTime;
    RTC_DateTypeDef mRtcDate;    
     if(RtcInterface == NULL)
            return;
    pRTC = (SoftWareRtcHal *)RtcInterface;
	
    xSeconds2Date(pRTC->mSecondCount, &mRtcDate, &mRtcTime);
    memcpy(RTC_DateStruct, &mRtcDate, sizeof(RTC_DateTypeDef));
}

void gRtcGetTime(SoftWareRtcInterface *RtcInterface, uint32_t RTC_Format, RTC_TimeTypeDef* RTC_TimeStruct){

    SoftWareRtcHal *pRTC;
    RTC_TimeTypeDef mRtcTime;
    RTC_DateTypeDef mRtcDate;       
    if(RtcInterface == NULL)
            return;
    pRTC = (SoftWareRtcHal *)RtcInterface;
	
    xSeconds2Date(pRTC->mSecondCount, &mRtcDate, &mRtcTime);
    memcpy(RTC_TimeStruct, &mRtcTime, sizeof(RTC_TimeTypeDef));

}

void InitSoftWareRtc(SoftWareRtcInterface *interface){

uint32_t err_code;
SoftWareRtcHal *pRtcHal = (SoftWareRtcHal *)interface;   

.............
err_code = app_timer_create(&pRtcHal->mSecondTimerId,
                 APP_TIMER_MODE_REPEATED,
                 gRtcAppTimerSecondHandle);
APP_ERROR_CHECK(err_code); 

err_code = app_timer_start(pRtcHal->mSecondTimerId, 
                APP_TIMER_TICKS(1000, APP_TIMER_PRESCALER), 
                pRtcHal);
APP_ERROR_CHECK(err_code); 

..............

}