222 lines
6.4 KiB
C
222 lines
6.4 KiB
C
/* Emulation of:
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Toshiba TC8521 Real Time Clock */
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include "nvr.h"
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#include "rtc_tc8521.h"
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#define peek2(a) (nvrram[(a##1)] + 10 * nvrram[(a##10)])
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struct
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{
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int sec;
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int min;
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int hour;
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int mday;
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int mon;
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int year;
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} internal_clock;
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/* Table for days in each month */
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static int rtc_days_in_month[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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/* Called to determine whether the year is leap or not */
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static int rtc_is_leap(int org_year)
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{
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if (org_year % 400 == 0) return 1;
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if (org_year % 100 == 0) return 0;
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if (org_year % 4 == 0) return 1;
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return 0;
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}
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/* Called to determine the days in the current month */
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static int rtc_get_days(int org_month, int org_year)
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{
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if (org_month != 2)
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return rtc_days_in_month[org_month];
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else
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return rtc_is_leap(org_year) ? 29 : 28;
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}
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/* Called when the internal clock gets updated */
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static void tc8521_recalc()
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{
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if (internal_clock.sec == 60)
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{
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internal_clock.sec = 0;
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internal_clock.min++;
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}
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if (internal_clock.min == 60)
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{
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internal_clock.min = 0;
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internal_clock.hour++;
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}
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if (internal_clock.hour == 24)
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{
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internal_clock.hour = 0;
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internal_clock.mday++;
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}
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if (internal_clock.mday == (rtc_get_days(internal_clock.mon, internal_clock.year) + 1))
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{
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internal_clock.mday = 1;
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internal_clock.mon++;
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}
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if (internal_clock.mon == 13)
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{
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internal_clock.mon = 1;
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internal_clock.year++;
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}
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}
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/* Called when ticking the second */
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void tc8521_tick()
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{
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internal_clock.sec++;
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tc8521_recalc();
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}
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/* Called when modifying the NVR registers */
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void tc8521_update(uint8_t *nvrram, int reg)
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{
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int temp;
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switch(reg)
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{
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case TC8521_SECOND1:
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case TC8521_SECOND10:
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internal_clock.sec = peek2(TC8521_SECOND);
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break;
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case TC8521_MINUTE1:
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case TC8521_MINUTE10:
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internal_clock.min = peek2(TC8521_MINUTE);
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break;
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case TC8521_HOUR1:
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case TC8521_HOUR10:
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temp = peek2(TC8521_HOUR);
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if (nvrram[TC8521_24HR] & 1)
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internal_clock.hour = temp;
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else
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internal_clock.hour = ((temp & ~0x20) % 12) + ((temp & 0x20) ? 12 : 0);
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break;
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case TC8521_DAY1:
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case TC8521_DAY10:
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internal_clock.mday = peek2(TC8521_DAY);
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break;
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case TC8521_MONTH1:
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case TC8521_MONTH10:
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internal_clock.mon = peek2(TC8521_MONTH);
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break;
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case TC8521_YEAR1:
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case TC8521_YEAR10:
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internal_clock.year = 1980 + peek2(TC8521_YEAR);
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break;
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}
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}
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/* Called to obtain the current day of the week based on the internal clock */
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static int time_week_day()
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{
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int day_of_month = internal_clock.mday;
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int month2 = internal_clock.mon;
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int year2 = internal_clock.year % 100;
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int century = ((internal_clock.year - year2) / 100) % 4;
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int sum = day_of_month + month2 + year2 + century;
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/* (Sum mod 7) gives 0 for Saturday, we need it for Sunday, so +6 for Saturday to get 6 and Sunday 0 */
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int raw_wd = ((sum + 6) % 7);
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return raw_wd;
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}
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/* Called to get time into the internal clock */
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static void tc8521_internal_get(struct tm *time_var)
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{
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time_var->tm_sec = internal_clock.sec;
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time_var->tm_min = internal_clock.min;
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time_var->tm_hour = internal_clock.hour;
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time_var->tm_wday = time_week_day();
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time_var->tm_mday = internal_clock.mday;
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time_var->tm_mon = internal_clock.mon - 1;
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time_var->tm_year = internal_clock.year - 1900;
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}
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static void tc8521_internal_set(struct tm *time_var)
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{
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internal_clock.sec = time_var->tm_sec;
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internal_clock.min = time_var->tm_min;
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internal_clock.hour = time_var->tm_hour;
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internal_clock.mday = time_var->tm_mday;
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internal_clock.mon = time_var->tm_mon + 1;
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internal_clock.year = time_var->tm_year + 1900;
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}
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static void tc8521_set_nvrram(uint8_t *nvrram, struct tm *cur_time_tm)
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{
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nvrram[TC8521_SECOND1] = cur_time_tm->tm_sec % 10;
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nvrram[TC8521_SECOND10] = cur_time_tm->tm_sec / 10;
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nvrram[TC8521_MINUTE1] = cur_time_tm->tm_min % 10;
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nvrram[TC8521_MINUTE10] = cur_time_tm->tm_min / 10;
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if (nvrram[TC8521_24HR] & 1)
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{
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nvrram[TC8521_HOUR1] = cur_time_tm->tm_hour % 10;
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nvrram[TC8521_HOUR10] = cur_time_tm->tm_hour / 10;
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}
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else
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{
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nvrram[TC8521_HOUR1] = (cur_time_tm->tm_hour % 12) % 10;
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nvrram[TC8521_HOUR10] = ((cur_time_tm->tm_hour % 12) / 10)
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| (cur_time_tm->tm_hour >= 12) ? 2 : 0;
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}
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nvrram[TC8521_WEEKDAY] = cur_time_tm->tm_wday;
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nvrram[TC8521_DAY1] = cur_time_tm->tm_mday % 10;
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nvrram[TC8521_DAY10] = cur_time_tm->tm_mday / 10;
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nvrram[TC8521_MONTH1] = (cur_time_tm->tm_mon + 1) / 10;
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nvrram[TC8521_MONTH10] = (cur_time_tm->tm_mon + 1) % 10;
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nvrram[TC8521_YEAR1] = (cur_time_tm->tm_year - 80) % 10;
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nvrram[TC8521_YEAR10] = ((cur_time_tm->tm_year - 80) % 100) / 10;
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}
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void tc8521_internal_set_nvrram(uint8_t *nvrram)
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{
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/* Load the entire internal clock state from the NVR. */
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internal_clock.sec = peek2(TC8521_SECOND);
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internal_clock.min = peek2(TC8521_MINUTE);
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if (nvrram[TC8521_24HR] & 1)
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{
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internal_clock.hour = peek2(TC8521_HOUR);
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}
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else
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{
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internal_clock.hour = (peek2(TC8521_HOUR) % 12)
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+ (nvrram[TC8521_HOUR10] & 2) ? 12 : 0;
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}
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internal_clock.mday = peek2(TC8521_DAY);
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internal_clock.mon = peek2(TC8521_MONTH);
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internal_clock.year = 1980 + peek2(TC8521_YEAR);
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}
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void tc8521_internal_sync(uint8_t *nvrram)
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{
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struct tm *cur_time_tm;
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time_t cur_time;
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time(&cur_time);
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cur_time_tm = localtime(&cur_time);
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tc8521_internal_set(cur_time_tm);
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tc8521_set_nvrram(nvrram, cur_time_tm);
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}
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void tc8521_get(uint8_t *nvrram)
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{
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struct tm cur_time_tm;
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tc8521_internal_get(&cur_time_tm);
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tc8521_set_nvrram(nvrram, &cur_time_tm);
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}
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