stm32 RTC实现 time函数

平台：STM32F4
编译器：arm-none-eabi-gcc

1. 定义全局变量

time_t time_dat;

2. 重定义time()函数

time_t time (time_t *_timer)
{
    struct tm *ts;
    if(_timer != NULL)
    {
        time_dat = *_timer;
        ts = localtime (_timer);
        RTC_Set_Time(ts->tm_hour, ts->tm_min, ts->tm_sec);
        RTC_Set_Date(ts->tm_year+1900-2000, ts->tm_mon+1, ts->tm_mday);
    }
    return time_dat;
}

3. 在秒中断中累加time_dat
   我是在WakeUp中断回调函数中累加

void HAL_RTCEx_WakeUpTimerEventCallback(RTC_HandleTypeDef *hrtc)
{
    time_dat ++;
}

4. 读取RTC初始化time_date
   需要注意的是tm结构体中月份tm_mon是从0开始的，tm_year是1900年之后的年数。

void timeInit()
{
    time_t settime;
    struct tm orig;
    RTC_TimeTypeDef RTC_TimeStruct;
    RTC_DateTypeDef RTC_DateStruct;

    HAL_RTC_GetTime(&RTC_Handler, &RTC_TimeStruct, RTC_FORMAT_BIN);
    HAL_RTC_GetDate(&RTC_Handler, &RTC_DateStruct, RTC_FORMAT_BIN);

    orig.tm_sec = RTC_TimeStruct.Seconds;
    orig.tm_min = RTC_TimeStruct.Minutes;
    orig.tm_hour = RTC_TimeStruct.Hours;
    orig.tm_mday = RTC_DateStruct.Date;
    orig.tm_mon = RTC_DateStruct.Month-1;
    orig.tm_year = 2000 + RTC_DateStruct.Year - 1900;
    orig.tm_isdst = -1;
    settime = mktime (&orig);
    time(&settime);
}

5. 使用time

    time_t now;
    struct tm *ts;
    char buf [80];

    now = time (NULL);
    ts = localtime (& now);
    strftime (buf, sizeof (buf), "%a %Y-%m-%d %H:%M:%S %Z", ts);
    printf_safe("%s \n", buf);