The M41T81S is a low-power serial real-time clock (RTC) with a built-in 32.768 kHz oscillator (external crystal controlled). Eight bytes of the SRAM are used for the clock/calendar function and are configured in binary-coded decimal (BCD) format. An additional 12 bytes of SRAM provide status/control of alarm, watchdog and square wave functions. Addresses and data are transferred serially via a two line, bidirectional I2C interface. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41T81S has a built-in power sense circuit which detects power failures and automatically switches to the battery supply when a power failure occurs. The energy needed to sustain the clock operations can be supplied by a small lithium button supply when a power failure occurs. Functions available to the user include a non-volatile, time-of-day clock/calendar, alarm interrupts, watchdog timer and programmable square wave output. The eight clock address locations contain the century, year, month, date, day, hour, minute, second and tenths/hundredths of a second in 24-hour BCD format. Corrections for 28, 29 (leap year - valid until year 2100), 30 and 31 day months are made automatically. The M41T81S is supplied in either an 8-pin SOIC or an 18-pin 300 mil SOIC package which includes an embedded 32 KHz crystal. The 18-pin, embedded crystal SOIC requires only a user-supplied battery to provide non-volatile operation. https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2020-06-04 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2021-04-04 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2021-04-17 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2021-07-14 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2021-07-22 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2021-12-06 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2022-04-08 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2022-06-14 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2022-06-22 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2023-11-15 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2023-12-10 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2024-01-05 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2024-01-14 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2024-01-31 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2024-10-31 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2024-11-09 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2024-11-18 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2025-01-11 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2025-01-20 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2025-07-11 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2026-01-28 https://elecena.pl/product/16941413/m41t81sm6f-serial-real-time-clock-rtc-with-alarm 2026-03-16