M41T82 datasheet(6/64 Pages) STMICROELECTRONICS

6 / 64 page

Description

M41T82, M41T83

6/64

DocID012578 Rev 19

Description

The M41T8x are low-power serial I2C real-time clocks (RTCs) with a built-in 32.768 kHz

oscillator (external crystal-controlled for the QFN16 and SO8 packages, embedded crystal

for the SOX18 package). Eight bytes of the register map (see Table 2 on page 23) are used

for the clock/calendar function and are configured in binary-coded decimal (BCD) format. An

additional 17 bytes of the register map provide status/control of the two alarms, watchdog,

8-bit counter, and square wave functions. An additional seven bytes are made available as

user SRAM.

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 M41T8x 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 battery

when a power failure occurs.

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

interrupts, watchdog timer, programmable 8-bit counter, and square wave outputs. 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 M41T83 is supplied in either a

QFN16 or an SOX18, 300 mil SOIC which includes an embedded 32 KHz crystal. The

SOX18 package requires only a user-supplied battery to provide non-volatile operation. The

M41T82 is available only in an SO8 package.

M41T82 Datasheet(PDF) 6 Page - STMicroelectronics