mirror of https://github.com/ARMmbed/mbed-os.git
214 lines
7.3 KiB
C
214 lines
7.3 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2015-2016 Nuvoton
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "rtc_api.h"
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#if DEVICE_RTC
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#include "mbed_wait_api.h"
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#include "mbed_error.h"
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#include "nu_modutil.h"
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#include "nu_miscutil.h"
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#include "mbed_mktime.h"
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/* Micro seconds per second */
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#define NU_US_PER_SEC 1000000
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/* Timer clock per second
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*
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* NOTE: This dependents on real hardware.
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*/
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#define NU_RTCCLK_PER_SEC (__LXT)
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/* Strategy for implementation of RTC HAL
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*
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* H/W RTC just supports year range 2000~2099, which cannot fully cover POSIX time (starting since 2970)
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* and date time of struct TM (starting since 1900).
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*
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* To conquer the difficulty, we don't use H/W RTC to keep real date time. Instead, we use it to keep
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* elapsed time in seconds since one reference time point. The strategy would be:
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*
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* 1. Choose DATETIME_HWRTC_ORIGIN (00:00:00 UTC, Saturday, 1 January 2000) as reference time point of H/W RTC.
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* 2. t_hwrtc_origin = DATETIME_HWRTC_ORIGIN in POSIX time
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* 3. t_hwrtc_elapsed = t_hwrtc_origin + elapsed time since t_hwrtc_origin
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* 4. t_write = POSIX time set by rtc_write().
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* 5. t_present = rtc_read() = t_write + (t_hwrtc_elapsed - t_hwrtc_origin)
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*
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* 1900
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* |---------------------------------------------------------------------------------|
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* 1970 t_write t_present
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* |---------|-------|-----------------|---------------------------------------------|
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*
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* 2000
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* |-----------------|---------------------------------------------------------------|
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* t_hwrtc_origin t_hwrtc_elapsed
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*
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*/
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/* Start year of struct TM*/
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#define NU_TM_YEAR0 1900
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/* Start year of POSIX time (set_time()/time()) */
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#define NU_POSIX_YEAR0 1970
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/* Start year of H/W RTC */
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#define NU_HWRTC_YEAR0 2000
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/* RTC H/W origin time: 00:00:00 UTC, Saturday, 1 January 2000 */
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static const S_RTC_TIME_DATA_T DATETIME_HWRTC_ORIGIN = {
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2000, /* Year value, range between 2000 ~ 2099 */
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1, /* Month value, range between 1 ~ 12 */
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1, /* Day value, range between 1 ~ 31 */
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RTC_SATURDAY, /* Day of the week */
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0, /* Hour value, range between 0 ~ 23 */
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0, /* Minute value, range between 0 ~ 59 */
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0, /* Second value, range between 0 ~ 59 */
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RTC_CLOCK_24, /* 12-Hour (RTC_CLOCK_12) / 24-Hour (RTC_CLOCK_24) */
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0 /* RTC_AM / RTC_PM (used only for 12-Hour) */
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};
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/* t_hwrtc_origin initialized or not? */
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static bool t_hwrtc_origin_inited = 0;
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/* POSIX time of DATETIME_HWRTC_ORIGIN (since 00:00:00 UTC, Thursday, 1 January 1970) */
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static time_t t_hwrtc_origin = 0;
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/* POSIX time set by rtc_write() */
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static time_t t_write = 0;
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/* Convert date time from H/W RTC to struct TM */
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static void rtc_convert_datetime_hwrtc_to_tm(struct tm *datetime_tm, const S_RTC_TIME_DATA_T *datetime_hwrtc);
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static const struct nu_modinit_s rtc_modinit = {RTC_0, RTC_MODULE, 0, 0, 0, RTC_IRQn, NULL};
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void rtc_init(void)
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{
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if (rtc_isenabled()) {
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return;
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}
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RTC_Open(NULL);
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/* POSIX time origin (00:00:00 UTC, Thursday, 1 January 1970) */
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rtc_write(0);
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}
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void rtc_free(void)
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{
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CLK_DisableModuleClock(rtc_modinit.clkidx);
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}
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int rtc_isenabled(void)
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{
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// NOTE: To access (RTC) registers, clock must be enabled first.
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if (! (CLK->APBCLK0 & CLK_APBCLK0_RTCCKEN_Msk)) {
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// Enable IP clock
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CLK_EnableModuleClock(rtc_modinit.clkidx);
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}
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// NOTE: Check RTC Init Active flag to support crossing reset cycle.
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return !! (RTC->INIT & RTC_INIT_INIT_Active_Msk);
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}
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time_t rtc_read(void)
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{
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/* NOTE: After boot, RTC time registers are not synced immediately, about 1 sec latency.
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* RTC time got (through RTC_GetDateAndTime()) in this sec would be last-synced and incorrect.
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*/
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if (! rtc_isenabled()) {
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rtc_init();
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}
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/* Used for intermediary between date time of H/W RTC and POSIX time */
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struct tm datetime_tm;
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if (! t_hwrtc_origin_inited) {
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t_hwrtc_origin_inited = 1;
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/* Convert date time from H/W RTC to struct TM */
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rtc_convert_datetime_hwrtc_to_tm(&datetime_tm, &DATETIME_HWRTC_ORIGIN);
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/* Convert date time of struct TM to POSIX time */
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if (! _rtc_maketime(&datetime_tm, &t_hwrtc_origin, RTC_FULL_LEAP_YEAR_SUPPORT)) {
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return 0;
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}
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/* Load t_write from RTC spare register to cross reset cycle */
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RTC_WaitAccessEnable();
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RTC_EnableSpareAccess();
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RTC_WaitAccessEnable();
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t_write = RTC_READ_SPARE_REGISTER(0);
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RTC_WaitAccessEnable();
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while (! (RTC->SPRCTL & RTC_SPRCTL_SPRRWRDY_Msk));
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}
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S_RTC_TIME_DATA_T hwrtc_datetime_2K_present;
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RTC_WaitAccessEnable();
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RTC_GetDateAndTime(&hwrtc_datetime_2K_present);
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/* Convert date time from H/W RTC to struct TM */
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rtc_convert_datetime_hwrtc_to_tm(&datetime_tm, &hwrtc_datetime_2K_present);
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/* Convert date time of struct TM to POSIX time */
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time_t t_hwrtc_elapsed;
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if (! _rtc_maketime(&datetime_tm, &t_hwrtc_elapsed, RTC_FULL_LEAP_YEAR_SUPPORT)) {
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return 0;
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}
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/* Present time in POSIX time */
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time_t t_present = t_write + (t_hwrtc_elapsed - t_hwrtc_origin);
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return t_present;
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}
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void rtc_write(time_t t)
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{
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if (! rtc_isenabled()) {
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rtc_init();
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}
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t_write = t;
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/* Store t_write to RTC spare register to cross reset cycle */
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RTC_WaitAccessEnable();
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RTC_EnableSpareAccess();
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RTC_WaitAccessEnable();
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RTC_WRITE_SPARE_REGISTER(0, t_write);
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RTC_WaitAccessEnable();
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while (! (RTC->SPRCTL & RTC_SPRCTL_SPRRWRDY_Msk));
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RTC_WaitAccessEnable();
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RTC_SetDateAndTime((S_RTC_TIME_DATA_T *) &DATETIME_HWRTC_ORIGIN);
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/* NOTE: When engine is clocked by low power clock source (LXT/LIRC), we need to wait for 3 engine clocks. */
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wait_us((NU_US_PER_SEC / NU_RTCCLK_PER_SEC) * 3);
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}
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/*
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struct tm
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tm_sec seconds after the minute 0-61
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tm_min minutes after the hour 0-59
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tm_hour hours since midnight 0-23
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tm_mday day of the month 1-31
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tm_mon months since January 0-11
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tm_year years since 1900
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tm_wday days since Sunday 0-6
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tm_yday days since January 1 0-365
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tm_isdst Daylight Saving Time flag
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*/
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static void rtc_convert_datetime_hwrtc_to_tm(struct tm *datetime_tm, const S_RTC_TIME_DATA_T *datetime_hwrtc)
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{
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datetime_tm->tm_year = datetime_hwrtc->u32Year - NU_TM_YEAR0;
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datetime_tm->tm_mon = datetime_hwrtc->u32Month - 1;
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datetime_tm->tm_mday = datetime_hwrtc->u32Day;
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datetime_tm->tm_wday = datetime_hwrtc->u32DayOfWeek;
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datetime_tm->tm_hour = datetime_hwrtc->u32Hour;
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if (datetime_hwrtc->u32TimeScale == RTC_CLOCK_12 && datetime_hwrtc->u32AmPm == RTC_PM) {
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datetime_tm->tm_hour += 12;
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}
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datetime_tm->tm_min = datetime_hwrtc->u32Minute;
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datetime_tm->tm_sec = datetime_hwrtc->u32Second;
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}
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#endif
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