How to enter deepsleep mode with LPC54114?

Hi all,
This is my code ( port.c) to enter deepsleep mode with LPC54114. It enters well but can not wakeup. Could you share your solution suggestions?

       /* Set the new reload value. */
        RTC_SetWakeupCount(pxRtcBase, ulReloadValue);

        /* Enable RTC. */
        RTC_StartTimer(pxRtcBase);

        /* Sleep until something happens.  configPRE_SLEEP_PROCESSING() can
        set its parameter to 0 to indicate that its implementation contains
        its own wait for interrupt or wait for event instruction, and so wfi
        should not be executed again.  However, the original expected idle
        time variable must remain unmodified, so a copy is taken. */
        xModifiableIdleTime = xExpectedIdleTime;
        configPRE_SLEEP_PROCESSING(xModifiableIdleTime);


        if (xModifiableIdleTime > 0)
        {
            __DSB();
            //__WFI();
            POWER_EnterDeepSleep(0xF0000U);
            __ISB();
        }

        configPOST_SLEEP_PROCESSING(xExpectedIdleTime);

This question is more for NXP than FreeRTOS and you are likely to get better response on NXP forums. A quick Google Search gives me this application note which provides the things you need to do so that an interrupt can wake up the MCU from deep sleep mode.