M41T81MX6TR STMicroelectronics, M41T81MX6TR Datasheet - Page 5
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M41T81MX6TR
Manufacturer Part Number
M41T81MX6TR
Description
Real Time Clock Serial 512 (64x8)
Manufacturer
STMicroelectronics
Datasheet
1.M41T81M6.pdf
(29 pages)
Specifications of M41T81MX6TR
Function
Clock, Calendar, Alarm, Timer Interrupt
Rtc Memory Size
20 B
Supply Voltage (max)
5.5 V
Supply Voltage (min)
2 V
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Mounting Style
SMD/SMT
Rtc Bus Interface
Serial
Package / Case
SO-28
Time Format
HH:MM:SS:hh
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
M41T81
1
Description
The M41T81 is a low-power serial 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 I
incremented automatically after each WRITE or READ data byte.
The M41T81 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 SRAM and 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 M41T81 is supplied in an 8-pin SOIC.
Figure 1.
Table 1.
IRQ/OUT/FT/SQW
V
SDA
SCL
V
V
XO
XI
BAT
CC
SS
Logic diagram
Signal names
Oscillator input
Oscillator output
Interrupt / output driver / frequency test / square wave (open drain)
Serial data input/output
Serial clock input
Battery supply voltage
Supply voltage
Ground
SDA
Doc ID 7529 Rev 10
SCL
XO
XI
V
CC
M41T81
V
SS
V
2
BAT
C interface. The built-in address register is
IRQ/FT/OUT/SQW
Description
AI04613
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