现象描述：RTC AlarmA 不进Standby模式，设置成一分钟闹铃一次，没问题，加长Standby，无法唤醒

主函数：
int main(void)
{
    u8 t = 0;
        u8 cnt = 0;
    char tbuf[40];

    RTC_TimeTypeDef RTC_TimeStruct;
    RTC_DateTypeDef RTC_DateStruct;

    HAL_Init();
    SystemClock_Config();                //3õê¼»ˉÏμí3ê±ÖóÎa80M
    delay_init(80);                         //3õê¼»ˉÑóê±oˉêy    80MÏμí3ê±Öó
    uart_init(115200);                        //3õê¼»ˉ′®¿ú￡¬2¨ìØÂêÎa115200
    usmart_dev.init(80);                //3õê¼»ˉUSMART                80MÏμí3ê±Öó

    LED_Init();                                        //3õê¼»ˉLED
    BEEP_Init();                                //3õê¼»ˉBEEP
    LCD_Init();                                        //3õê¼»ˉLCD

    RTC_Init();                                        //3õê¼»ˉRTC
        RTC_Set_AlarmA(0, 0, 0, 5);        //
    RTC_Set_WakeUp(RTC_WAKEUPCLOCK_CK_SPRE_16BITS, 0); //ÅäÖÃWAKE UPÖD¶Ï,1ÃëÖóÖD¶Ïò»′Î

        POINT_COLOR = RED;
    Display_ALIENTEK_LOGO(0, 0);
    LCD_ShowString(30, 95, 200, 16, 16, "Pandora STM32L4 IOT");
    LCD_ShowString(30, 115, 200, 16, 16, "RTC TEST");
    LCD_ShowString(30, 135, 200, 16, 16, "ATOM@ALIENTEK");
    LCD_ShowString(30, 155, 200, 16, 16, "2018/10/27");
        POINT_COLOR = BLUE;
       
    while(1)
    {
        t++;

        if((t % 10) == 0)                        //ÿ100ms¸üDÂò»′ÎÏÔê¾êy¾Y
        {
            HAL_RTC_GetTime(&RTC_Handler, &RTC_TimeStruct, RTC_FORMAT_BIN);
            sprintf((char*)tbuf, "Time:%02d:%02d:%02d", RTC_TimeStruct.Hours, RTC_TimeStruct.Minutes, RTC_TimeStruct.Seconds);
            LCD_ShowString(30, 175, 210, 16, 16, tbuf);
            HAL_RTC_GetDate(&RTC_Handler, &RTC_DateStruct, RTC_FORMAT_BIN);
            sprintf((char*)tbuf, "Date:20%02d-%02d-%02d", RTC_DateStruct.Year, RTC_DateStruct.Month, RTC_DateStruct.Date);
            LCD_ShowString(30, 195, 210, 16, 16, tbuf);
            sprintf((char*)tbuf, "Week:%d", RTC_DateStruct.WeekDay);
            LCD_ShowString(30, 215, 210, 16, 16, tbuf);
        }

                if( BEEP_Read )                                //ÄÖÖóμ½ê±￡¬·äÃùÆ÷Ïì1Soóí￡Ö1
                {
                        cnt++;
                        if(cnt>=100)        {BEEP(0);cnt=0;}
                }
               
        if((t % 20) == 0)LED_R_TogglePin;        //ÿ200ms,·-×aò»′ÎLED_R

        delay_ms(10);
                Sys_Enter_Standby();
    }
}


void RTC_Set_AlarmA(u8 week, u8 hour, u8 min, u8 sec)
{
    RTC_AlarmTypeDef RTC_AlarmSturuct;

    RTC_AlarmSturuct.AlarmTime.Hours = hour; //D¡ê±
    RTC_AlarmSturuct.AlarmTime.Minutes = min; //·ÖÖó
    RTC_AlarmSturuct.AlarmTime.Seconds = sec; //Ãë
    RTC_AlarmSturuct.AlarmTime.SubSeconds = 0;
    RTC_AlarmSturuct.AlarmTime.TimeFormat = RTC_HOURFORMAT12_AM;

    RTC_AlarmSturuct.AlarmMask = RTC_ALARMMASK_DATEWEEKDAY | RTC_ALARMMASK_HOURS | RTC_ALARMMASK_MINUTES;//¾«è·Æ￥ÅäDÇÆú￡¬ê±·ÖÃë;RTC_ALARMMASK_NONE; //¾«è·Æ￥ÅäDÇÆú￡¬ê±·ÖÃë
    RTC_AlarmSturuct.AlarmSubSecondMask = RTC_ALARMSUBSECONDMASK_NONE;
    RTC_AlarmSturuct.AlarmDateWeekDaySel = RTC_ALARMDATEWEEKDAYSEL_WEEKDAY; //°′DÇÆú
    RTC_AlarmSturuct.AlarmDateWeekDay = week; //DÇÆú
    RTC_AlarmSturuct.Alarm = RTC_ALARM_A;   //ÄÖÖóA
    HAL_RTC_SetAlarm_IT(&RTC_Handler, &RTC_AlarmSturuct, RTC_FORMAT_BIN);

    HAL_NVIC_SetPriority(RTC_Alarm_IRQn, 0x01, 0x02); //ÇàÕ¼óÅÏ輶1,×óóÅÏ輶2
    HAL_NVIC_EnableIRQ(RTC_Alarm_IRQn);
}


void Sys_Enter_Standby(void)
{
        __HAL_RCC_AHB2_FORCE_RESET();       //¸′λËùóDIO¿ú
       
        __HAL_RCC_PWR_CLK_ENABLE();         //ê1ÄüPWRê±Öó
    __HAL_RCC_BACKUPRESET_FORCE();      //¸′λ±¸·YÇøóò
    HAL_PWR_EnableBkUpAccess();         //oó±¸Çøóò·ÃÎêê1Äü  
       
        //STM32F4,μ±¿aÆôáËRTCÏà1ØÖD¶Ïoó,±ØDëÏè1رÕRTCÖD¶Ï,ÔùÇåÖD¶Ï±ê־λ,è»oóÖØDÂéèÖÃ
        //RTCÖD¶Ï,Ôù½øèë′y»úÄ￡ê½2Å¿éòÔÕy3￡»½DÑ,·ñÔò»áóDÎêìa.       
    __HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB);
    __HAL_RTC_WRITEPROTECTION_DISABLE(&RTC_Handler);//1رÕRTCD′±￡»¤

    //1رÕRTCÏà1ØÖD¶Ï￡¬¿éÄüÔúRTCêμÑé′ò¿aáË
    __HAL_RTC_WAKEUPTIMER_DISABLE_IT(&RTC_Handler,RTC_IT_WUT);
    __HAL_RTC_TIMESTAMP_DISABLE_IT(&RTC_Handler,RTC_IT_TS);
    __HAL_RTC_ALARM_DISABLE_IT(&RTC_Handler,RTC_IT_ALRA|RTC_IT_ALRB);

    //Çå3yRTCÏà1ØÖD¶Ï±ê־λ
    __HAL_RTC_ALARM_CLEAR_FLAG(&RTC_Handler,RTC_FLAG_ALRAF|RTC_FLAG_ALRBF);
    __HAL_RTC_TIMESTAMP_CLEAR_FLAG(&RTC_Handler,RTC_FLAG_TSF);
    __HAL_RTC_WAKEUPTIMER_CLEAR_FLAG(&RTC_Handler,RTC_FLAG_WUTF);

    __HAL_RCC_BACKUPRESET_RELEASE();                    //±¸·YÇøóò¸′λ½áêø
    __HAL_RTC_WRITEPROTECTION_ENABLE(&RTC_Handler);     //ê1ÄüRTCD′±￡»¤
    __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);                  //Çå3yWake_UP±êÖ¾
       
               
    HAL_PWR_EnableWakeUpPin(PWR_WAKEUP_PIN2);           //éèÖÃWKUPóÃóú»½DÑ
    HAL_PWR_EnterSTANDBYMode();                         //½øèë′y»úÄ￡ê½     
}