M41T93_11 STMICROELECTRONICS [STMicroelectronics], M41T93_11 Datasheet - Page 6

• Manufacturer Part Number: M41T93_11
• Description: Serial SPI bus real-time clock with battery switchover
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Description
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The M41T93 is a low-power serial SPI bus real-time clock with a built-in 32.768 kHz
oscillator (external crystal-controlled for the QFN16 package, and embedded crystal for the
SOX18 package). Eight bytes of the register map 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 serial SPI bus-compatible interface. The
built-in address register is incremented automatically after each WRITE or READ data byte.
The M41T93 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, alarm
interrupt, 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 M41T93 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.
Description
Doc ID 12615 Rev 6
M41T93