M41T66 datasheet(5/33 Pages) STMICROELECTRONICS

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M41T66

Description

5/33

Description

The M41T66 serial access TIMEKEEPER® is a low power serial RTC with a built-in

32.768 kHz oscillator (external crystal controlled). Eight registers (see Table 2 on page 15)

are used for the clock/calendar function and are configured in binary coded decimal (BCD)

format. An additional 8 registers provide status/control of alarm, square wave, calibration,

and watchdog 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.

Functions available to the user include a time-of-day clock/calendar, alarm interrupts,

programmable square wave output, and watchdog 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), 30- and 31-day months

are made automatically.

The M41T66 is supplied in a 16-pin QFN.

Figure 1.

M41T66 logic diagram

Open drain

Defaults to 32 KHz on power-up

M41T66 Datasheet(PDF) 5 Page - STMicroelectronics