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non-breaking fix year in DS3231 (#17803)

This commit is contained in:
Barbudor 2023-01-28 08:04:34 +01:00 committed by GitHub
parent f064250d9a
commit 4dd97a9e82
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1 changed files with 11 additions and 2 deletions
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13
tasmota/tasmota_xdrv_driver/xdrv_56_rtc_chips.ino
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@ -80,7 +80,14 @@ uint32_t DS3231ReadTime(void) {
tm.day_of_week = I2cRead8(RtcChip.address, DS3231_DAY);
tm.day_of_month = Bcd2Dec(I2cRead8(RtcChip.address, DS3231_DATE));
tm.month = Bcd2Dec(I2cRead8(RtcChip.address, DS3231_MONTH) & ~_BV(DS3231_CENTURY)); // Don't use the Century bit
tm.year = Bcd2Dec(I2cRead8(RtcChip.address, DS3231_YEAR));
// MakeTime requires tm.year as number of years since 1970,
// However DS3231 is supposed to hold the true year but before this PR it was written tm.year directly
// Assuming we read ... means ...
// 00..21 = 1970..1990 written before PR (to support a RTC written with 1970) => don't apply correction
// 22..51 = 2022..2051 written after PR => apply +30 years correction
// 52..99 = 2022..2069 written before PR => don't apply correction
uint8_t year = Bcd2Dec(I2cRead8(RtcChip.address, DS3231_YEAR));
tm.year = ((year <= 21) || (year >= 52)) ? (year) : (year+30);
return MakeTime(tm);
}
@ -137,7 +144,9 @@ void DS3231SetTime(uint32_t epoch_time) {
I2cWrite8(RtcChip.address, DS3231_DAY, tm.day_of_week);
I2cWrite8(RtcChip.address, DS3231_DATE, Dec2Bcd(tm.day_of_month));
I2cWrite8(RtcChip.address, DS3231_MONTH, Dec2Bcd(tm.month));
I2cWrite8(RtcChip.address, DS3231_YEAR, Dec2Bcd(tm.year));
// BreakTime returns tm.year as number of years since 1970, while DS3231 expect the true year. Adusting to avoir leap year error
uint8_t true_year = (tm.year < 30) ? (tm.year + 70) : (tm.year - 30);
I2cWrite8(RtcChip.address, DS3231_YEAR, Dec2Bcd(true_year));
I2cWrite8(RtcChip.address, DS3231_STATUS, I2cRead8(RtcChip.address, DS3231_STATUS) & ~_BV(DS3231_OSF)); // Clear the Oscillator Stop Flag
}