stm32的RTC操作

2、date.c

#include "date.h"

#define FEBRUARY 2
#define STARTOFTIME 1970
#define SECDAY 86400L
#define SECYR (SECDAY * 365)
#define leapyear(year) ((year) % 4 == 0)
#define days_in_year(a) (leapyear(a) ? 366 : 365)
#define days_in_month(a) (month_days[(a) - 1])

static int month_days[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

/*
* This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
*/
/*计算公历*/
void GregorianDay(struct rtc_time * tm)
{
int leapsToDate;
int lastYear;
int day;
int MonthOffset[] = { 0,31,59,90,120,151,181,212,243,273,304,334 };

lastYear=tm->tm_year-1;

/*计算从公元元年到计数的前一年之中一共经历了多少个闰年*/
leapsToDate = lastYear/4 - lastYear/100 + lastYear/400;
/*如若计数的这一年为闰年，且计数的月份在2月之后，则日数加1，否则不加1*/
if((tm->tm_year%4==0) &&
((tm->tm_year%100!=0) || (tm->tm_year%400==0)) &&
(tm->tm_mon>2)) {
/*
* We are past Feb. 29 in a leap year
*/
day=1;
} else {
day=0;
}
day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + tm->tm_mday ; /*计算从公元元年元旦到计数日期一共有多少天*/

tm->tm_wday=day%7;
}

/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
* => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
*
* [For the Julian calendar (which was used in Russia before 1917,
* Britain & colonies before 1752, anywhere else before 1582,
* and is still in use by some communities) leave out the
* -year/100+year/400 terms, and add 10.]
*
* This algorithm was first published by Gauss (I think).
*
* WARNING: this function will overflow on 2106-02-07 06:28:16 on
* machines were long is 32-bit! (However, as time_t is signed, we
* will already get problems at other places on 2038-01-19 03:14:08)

*ADD by fire：本函数在工程中的输入参数为北京时间，
所以在转换成时间戳时最后要从北京时间转换为标准时间的时间戳
*/
u32 mktimev(struct rtc_time *tm)
{
if (0 >= (int) (tm->tm_mon -= 2)) { /* 1..12 -> 11,12,1..10 */
tm->tm_mon += 12; /* Puts Feb last since it has leap day */
tm->tm_year -= 1;
}

return (((
(u32) (tm->tm_year/4 - tm->tm_year/100 + tm->tm_year/400 + 367*tm->tm_mon/12 + tm->tm_mday) +
tm->tm_year*365 - 719499
)*24 + tm->tm_hour /* now have hours */
)*60 + tm->tm_min /* now have minutes */
)*60 + tm->tm_sec-8*60*60; /* finally seconds */
/*Add by fire: -8*60*60 把输入的北京时间转换为标准时间，
再写入计时器中，确保计时器的数据为标准的UNIX时间戳*/
}

void to_tm(u32 tim, struct rtc_time * tm)
{
register u32 i;
register long hms, day;

day = tim / SECDAY;
hms = tim % SECDAY;
/* Hours, minutes, seconds are easy */
tm->tm_hour = hms / 3600;
tm->tm_min = (hms % 3600) / 60;
tm->tm_sec = (hms % 3600) % 60;
/* Number of years in days */ /*算出当前年份，起始的计数年份为1970年*/
for (i = STARTOFTIME; day >= days_in_year(i); i++) {
day -= days_in_year(i);
}
tm->tm_year = i;
/* Number of months in days left */ /*计算当前的月份*/
if (leapyear(tm->tm_year)) {
days_in_month(FEBRUARY) = 29;
}
for (i = 1; day >= days_in_month(i); i++) { //程序编写时间是2013年8月
day -= days_in_month(i);
}
days_in_month(FEBRUARY) = 28;
tm->tm_mon = i;
/* Days are what is left over (+1) from all that. *//*计算当前日期*/
tm->tm_mday = day + 1;//+ 1; //2013年8月3日修改，实现功能
/*
* Determine the day of week
*/
GregorianDay(tm);

}

对外接口:

函数:init_rtc(),drv_set_time(),drv_get_time().

变量:extern struct rtc_time systemtime;