M41T80M View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
M41T80M Datasheet PDF : 27 Pages
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Clock operation
Table 5.
Square wave output frequency
Square wave bits
RS3
RS2
RS1
RS0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
M41T80
Square wave
Frequency
None
32.768
8.192
4.096
2.048
1.024
512
256
128
64
32
16
8
4
2
1
Units
-
kHz
kHz
kHz
kHz
kHz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
3.3
Note:
3.4
Full-time 32 KHz square wave output
The M41T80 offers the user a special 32 KHz square wave function which defaults to output
on the F32K pin (pin 3) as long as VCC is valid, and the oscillator is running (ST bit = '0'). This
function is available within four seconds of initial power-up and can only be disabled by
setting the 32KE bit to '0' or the ST bit to '1.' If not used, the F32K pin should be disconnected
and allowed to float.
The F32K pin is an open drain which requires an external pull-up resistor.
Century bit
Bits D7 and D6 of clock register 03h contain the CENTURY ENABLE bit (CEB) and the
CENTURY bit (CB). Setting CEB to a '1' will cause CB to toggle, either from a '0' to '1' or
from '1' to '0' at the turn of the century (depending upon its initial state). If CEB is set to a '0,'
CB will not toggle.
16/27
Doc ID 9074 Rev 5
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