M41T80_11 STMICROELECTRONICS [STMicroelectronics], M41T80_11 Datasheet - Page 5

• Manufacturer Part Number: M41T80_11
• Description: Serial access real-time clock with alarm
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M41T80
1
Description
The M41T80 is a low power serial RTC with a built-in 32.768 kHz oscillator (external crystal
controlled). Eight registers (see
clock/calendar function and are configured in binary coded decimal (BCD) format. An
additional 12 registers provide status/control of alarm, 32 KHz output, and square wave
functions. Addresses and data are transferred serially via a two line, bi-directional I
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,
32 KHz output, 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 M41T80 is supplied in an 8-pin SOIC.
Figure 1.
Table 1.
IRQ/OUT/SQW
Logic diagram
Signal names
SDA
F
SCL
V
V
XO
XI
32K
CC
SS
SDA
SCL
Doc ID 9074 Rev 5
XO
Table 3: Clock register map on page
XI
Oscillator input
Oscillator output
Interrupt / output driver / square wave (open drain)
Serial data input/output
Serial clock input
32 KHz square wave output (open drain)
Supply voltage
Ground
M41T80
V CC
V SS
F 32K
IRQ/OUT/SQW
14) are used for the
Description
2
C
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