6) Re-chargeable battery control (INIEN:1, CHGEN:1)
Figure 29 Battery Backup Switchover Control (rechargeable battery)
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
OUT
) 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.
Table 47 SMPT bit (Sample Time)
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