User Manual

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Vbat
This pin directly connects to the “+” terminal of the super capacitor. By measuring the
voltage of this pin, you know if the capacitor is fully charged (3.3V means full). If you
want to have a (much) longer off-power time keeping duration, you can connect your
own 3V battery to this pad.
If you use the rechargeable battery, you just need to connect it directly to Vbat and
GND pads. Witty Pi Mini will charge this battery with trickle current, when the power
supply is connected.
If you use non-rechargeable battery, you will need to use a diode to make sure the
battery will be discharged only.
INT
It is the interrupt signal that generated by the RTC alarm. It is in 5V level and has
HIGH state (5V) by default. If any alarm occurs (scheduled startup or shutdown), it
goes to LOW state (0V), and this state will be cleared once Witty Pi Mini’s software
detects and process it.
If the alarm occurs when Witty Pi Mini is not powered, the INT pad will stay in LOW
state. When power is back online, your Raspberry Pi will boot immediately.