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6. RTC battery
STM32 M4 clicker features RTC battery pads for
powering microntroller’s internal RTC module. Battery
is used as an alternative source of power, so the
RTC module can keep track of time while primary
source of power is OFF or unavailable. In order to
use this option it is necessary to connect (solder)
external battery (type CR2032; voltage range from
1.65 to 3.6 V) and unsolder jumper J1, Figure 6-1.
Make sure that orientation of the battery is correct
(plus on VBAT and minus on GND pad), otherwise it
won’t work properly.
Figure 6-1:
battery pads
and jumper J1
