m41t80 STMicroelectronics, m41t80 Datasheet - Page 5

• Manufacturer Part Number: m41t80
• Description: Serial Access Real Time Clock With Alarm
• Manufacturer: STMicroelectronics

M41T80
1
Summary description
The M41T80 is a low power Serial RTC with a built-in 32.768kHz 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, 32kHz 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, 32kHz
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
SCL
F
V
V
XO
XI
32k
CC
SS
SDA
SCL
XO
XI
Table 3: Clock register map on page
Oscillator input
Oscillator output
Interrupt / output driver / square wave (open drain)
Serial data input/output
Serial clock input
32kHz square wave output (open drain)
Supply voltage
Ground
M41T80
V SS
V CC
F 32k
IRQ/OUT/SQW
AI07005
Summary description
14) are used for the
2
C
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