RTC_YEAR2
tm->tm_year = bcd2bin(regs[RTC_YEAR2]) * 100 +
regs[RTC_YEAR2] = bin2bcd(high);
buf[RTC_YEAR2] = (high << 4) + low;
tm->tm_year = (buf[RTC_YEAR2] >> 4) * 1000
+ (buf[RTC_YEAR2] & 0xf) * 100
data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);
tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;