UPS for the Raspberry Pi boards. It connects directly over the 40 way Bus, but does not use any of the GPIO.
It supplies uinteruptable 5V to the Raspi board without any software. This is useful when just working on projects and you have no wish to start over when a power interupt occurs.
However simple software commands can be sent via the i2c bus to monitor & control the UPS.
It can optionaly use its own 3.3V or the Raspi supply.
The UPS adds an RTC as for example in my application it is operating with the Pi Zero with no wifi available and I wanted to log data in real time.
With a 2000ma LiPo cell my set gives over 2 hours backup.
When the Raspi is closed down either from auto or manual command, there is zero LiPo current drain.