Backup Batteries - sparkfun ZED-F9P Hook-Up Manual

Backup Batteries

There are two built-in backup batteries (ML414H) on the board. The backup battery has a 1mAh capacity and
requires 20 minute to charge. The battery near the SMA connector is for the Processor Board's RTC and helps
keep the RTC running when the external power is removed. Depending on the processor, it may not be connected.
The other one that is closest to the USB C connector labeled as u-center is for the ZED-F9P module. The
rechargeable battery maintains the battery backed RAM (BBR) on the GNSS module. This allows for much faster
position locks (a.k.a. hot start). The BBR is also used for module configuration retention. The battery is
automatically trickle charged when power is applied and should maintain settings and GNSS orbit data for up to
two weeks without power.
Reset and Boot Buttons
The reset button will reset the processor. The boot button will put the processor into a special boot mode.
Depending on the processor board, this boot pin may not be connected.