RTC_WDAY_SHIFT
| ((wday + 1) << RTC_WDAY_SHIFT)
tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
time = time | (0x7 << RTC_WDAY_SHIFT);
#define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */