DS3231_HOUR
if (data[DS3231_HOUR] & DS3231_HOUR_USE_AMPM) {
bct.hour = data[DS3231_HOUR] & hourmask;
bct.ispm = data[DS3231_HOUR] & DS3231_HOUR_IS_PM;
data[DS3231_HOUR] = bct.hour | pmflags;