m41t83 STMicroelectronics, m41t83 Datasheet - Page 40

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

3.9
Note:
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Table 12.
1. Writing to the timer register will not reset the TF bit or clear the interrupt.
Square wave output
The M41T83 offers the user a programmable square wave function which is output on the
SQW pin. RS3-RS0 bits located in 13h establish the square wave output frequency. These
frequencies are listed in
completed, the SQW pin can be turned on and off under software control with the Square
Wave Enable bit (SQWE) located in Register 0Ah.
If the SQWE bit is set to '1' and V
wave output will be disabled.
Table 13.
RS3
7 - 0
Bit
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Timer countdown value register bits (addr 11h)
Square wave output frequency
<timer countdown value>
RS2
Square wave bits
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Table
Symbol
13. Once the selection of the SQW frequency has been
(M41T83 only)
CC
RS1
falls below the switchover (V
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
This register holds the loaded countdown value ‘n’.
Countdown period = n / source clock frequency.
RS0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Description
(1)
Frequency
SO
32.768
8.192
4.096
2.048
1.024
None
512
256
128
) voltage, the square
64
32
16
8
4
2
1
Square wave
Units
kHz
kHz
kHz
kHz
kHz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
–