M41T60 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'M41T60' PDF : 27 Pages View PDF
M41T60
Figure 12. Calibration waveform
NORMAL
POSITIVE
CALIBRATION
NEGATIVE
CALIBRATION
Clock operation
AI00594b
3.2
3.3
Note:
3.4
Century bits
These two bits will increment in a binary fashion at the turn of the century, and handle leap
years correctly. See Table 3 on page 16 for additional explanation.
Output driver pin
When the OFIE bit is not set to generate an interrupt, the OFIRQ/OUT pin becomes an
output driver that reflects the contents of D7 of the calibration register. In other words, when
D7 (OUT bit) is a '0,' then the OFIRQ/OUT pin will be driven low.
The OFIRQ/OUT pin is an open drain which requires an external pull-up resistor.
Oscillator stop detection
In the event that the oscillator has either stopped, or was stopped for some period of time,
and if the oscillator fail interrupt enable (OFIE) bit is set to a '1,' an interrupt will be
generated. This interrupt can be used to judge the validity of the clock and date data.
The interrupt will be active any time the oscillator stops while VCC is ≥ 1.0V. The following
conditions will cause the OFIRQ pin to be active:
● the ST bit is set to '1.'
● external interference or removal of the crystal.
The oscillator fail interrupt (OFIRQ) will remain active until the OFIE bit is reset to '0,' or the
oscillator restarts.
The oscillator must start and have run for at least 4 seconds before attempting to set the
OFIE bit to '1.'
Doc ID 10396 Rev 13
15/27
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