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14. How to use
RX4111CE
Jump to
ETM62E-02
Seiko Epson Corporation
41
Figure 31 Battery backup switchover control (INIEN:1)
4) SMPT1, SMPT0 bit
7) V
DD
voltage detection register SMPT1, SMPT0 bit Battery switchover functions managed by V
DD
voltage
low detection (-V
DET1
).
This detection is checking voltage anytime with setting SW1(V
DD
- ~ V
BAT
) ON/OFF intermittently.
These two bits control SW1 OFF period and user can check much precision voltage by preventing reverse current from
V
BAT
to V
DD
when main V
DD
shuts down.
V
DD
voltage low detection (-V
DET1
) is active anytime, so lower voltage detection moves RTC into backup mode
immediately regardless SW1 OFF time.
These SW1 OFF occur every second.
Refer to Figure 31
Table 49 SMPT bit (sample time)
SMPT1
SMPT 0
SW OFF time
0
0
Always ON
0
1
2 ms
1
0
128 ms
1
1
256 ms
Once per a Second.