m41t83 STMicroelectronics, m41t83 Datasheet - Page 14

• Manufacturer Part Number: m41t83
• Description: Serial I 2c Bus Rtc With Battery Switchover
• Manufacturer: STMicroelectronics

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Operation
The M41T8x clock operates as a slave device on the serial bus. Access is obtained by
implementing a start condition followed by the correct slave address (D0h). The 32 bytes
contained in the device can then be accessed sequentially in the following order:
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The M41T8x clock continually monitors V
fall below V
counter. Inputs to the device will not be recognized at this time to prevent erroneous data
from being written to the device from an out-of-tolerance system. The power input will also
be switched from the V
switchover voltage (V
attached battery supply. As system power returns and V
disconnected, and the power supply is switched to external V
1
2
3
4
5
6
7
8
9
10
11
16
17
18
19
20
21
26
st
nd
rd
th
th
th
th
th
th
th
th
th
th
th
th
th
st
th
byte: tenths/hundredths of a second register
byte: century/hours register
byte: day register
byte: date register
byte: month register
byte: year register
byte: digital calibration register
byte: minutes register
byte: seconds register
- 25
byte: watchdog register
- 15
byte: flags register
byte: timer value register
byte: timer control register
byte: analog calibration register
byte: square wave register
- 32
RST
th
th
nd
, the device terminates an access in progress and resets the device address
bytes: alarm 2 registers
bytes: alarm 1 registers
bytes: user RAM
SO =
CC
pin to the battery when V
V
RST
). At this time the clock registers will be maintained by the
CC
for an out-of-tolerance condition. Should V
CC
falls below the battery back-up
CC
rises above V
CC
.
SO
, the battery is
CC