RV-3029 Datasheet, PDF (23/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
Example Power Up sequence, Low Voltage detection and Backup Supply switchover
RV-3029
1 _{Power Up Reset is executed; registers are loaded with Reset Values. PON flag is set at Power up}
indicating that time / date information likely are corrupted.
Low voltage detection flags V_LOW1 and V_LOW2 are automatically cleared.
2 _{PON Flag needs to be cleared by software writing “0”.}
3 _{Trickle charge circuitry for backup battery can be enabled by software.}
4
Switchover to the backup supply voltage when V_DD drops below V_DD < (V_BAT – 20mV).
5 _{Low voltage detection sets VLOW1 Flag when supply voltage drops VLOW1 threshold.}
6 _{Low voltage detection sets VLOW2 Flag when supply voltage drops VLOW2 threshold.}
7
Switchback from backup supply voltage to main supply voltage when V_DD rise above V_DD > (V_BAT + 20mV).
8 _{VLOW1 and VLOW2 Flags need to be cleared by software writing “0”.}
4.1.2.SUPPLY VOLTAGE OPERATING RANGE AND LOW VOLTAGE DETECTION
The RV-3029 has built-in low supply voltage detection which periodically monitors supply voltage levels vs. V_LOW1
and V_LOW2 thresholds.
If low supply voltage is detected, the corresponding flags V_LOW1 and V_LOW2 are set = “1”. Device functions critical to
low supply voltage are disabled.
During power up, the Low Voltage Detection is monitoring the supply voltage at an accelerated scan rate. If power
supply voltage exceed V_LOW2 threshold, the flags V_LOW1 and V_LOW2 are cleared and the scan rate for the low voltage
detection is set to 1 second.
23/67