M41ST87YMX6TR View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
M41ST87YMX6TR
STMicroelectronics
'M41ST87YMX6TR' PDF : 42 Pages View PDF
M41ST87Y, M41ST87W
Electronic Serial Number
The M41ST87Y/W has a unique 8-Byte lasered,
serial number with parity. This serial number is
“Read only” and is generated such that no two de-
vices will contain an identical number.
Oscillator Stop Detection
If the Oscillator Fail (OF) Bit is internally set to a '1,'
this indicates that the oscillator has either stopped,
or was stopped for some period of time and can be
used to judge the validity of the clock and date da-
ta. This bit will be set to '1' any time the oscillator
stops. The following conditions can cause the OF
Bit to be set:
– The first time power is applied (defaults to a '1'
on power-up).
– The voltage present on VCC or battery is insuffi-
cient to support oscillation.
– The ST Bit is set to '1.'
If the Oscillator Fail Interrupt Enable Bit (OFIE) is
set to a '1,' the IRQ/OUT pin will also be activated.
The IRQ/OUT output is cleared by resetting the
OF Bit to '0,' resetting the OFIE Bit to '0,' or the
RST output is enabled (NOT by reading the Flag
Register).
The OF Bit will remain set to '1' until written to logic
'0.' The oscillator must start and have run for at
least 4 seconds before attempting to reset the OF
Bit to '0.' This function operates both under normal
power and in battery back-up. If the trigger event
occurs during a power-down condition, this bit will
be set correctly.
Note: The ABE Bit must be set to '1' for the IRQ/
OUT pin to be activated in battery back-up.
Initial Power-on Defaults
See Table 13., page 34.
Table 11. Century Bits Examples
CB0
CB1
Leap Year?
Example(1)
0
0
Yes
2000
0
1
No
2100
1
0
No
2200
1
1
No
2300
Note: 1. Leap year occurs every four years (for years evenly divisible by four), except for years evenly divisible by 100. The only exceptions
are those years evenly divisible by 400 (the year 2000 was a leap year, year 2100 is not).
Table 12. trec Definitions
trec Bit (TR)
0
0
1
Note: 1. Default Setting
STOP Bit (ST)
0
1
X
trec Time
Min
Max
96
98(1)
40
200
50
2000
Units
ms
ms
µs
33/42
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