The built-in power-sense circuit continuously monitors the status of VCC to detect power failures and automatically switches to the backup supply. The DS3231 IC incorporates a battery input for maintaining accurate timekeeping even when the device’s main power is interrupted. This doesn’t mean that the DS1307 isn’t accurate it’s still a great RTC that will serve you well, but if your project needs more accurate timekeeping, the DS3231 is a better choice. The DS3231, on the other hand, is much more accurate because it has an internal Temperature Compensated Crystal Oscillator (TCXO) that isn’t affected by temperature, making it accurate to a few minutes per year at most. As a result, the clock is usually off by about five minutes per month. The DS1307 requires an external 32kHz crystal for timekeeping, the frequency of which is easily affected by external temperature. The primary difference between the DS3231 and the DS1370 is the accuracy of timekeeping. To avoid such minor crystal drifts, the DS3231 is powered by a 32kHz temperature compensated crystal oscillator (TCXO), which is highly resistant to external temperature changes. This change in frequency is negligible, but it adds up. The issue with these crystals is that their oscillation frequency is affected by external temperature. Most RTC modules, such as the DS1307, require an external 32kHz crystal oscillator for timekeeping. Temperature Compensated Crystal Oscillator(TCXO) This clock output may be useful in some applications for measuring clock timing accuracy or clocking other circuits. The INT/SQW pin on the DS3231 provides either an interrupt signal (due to alarm conditions) or a nice square wave at 1Hz, 4kHz, 8kHz, or 32kHz.Īdditionally, the DS3231 outputs a stable (temperature compensated) and accurate reference clock on the 32K pin.

It also has two time-of-day alarms that can be programmed.

It can work in either a 12-hour or 24-hour format and has an AM/PM indicator. For months with fewer than 31 days, it automatically adjusts the date at the end of the month, including leap year corrections (valid up to 2100). The DS3231 can keep track of seconds, minutes, hours, days, dates, months, and years.

Rtc ic ds3231 wire library