Datasheet

Functional overview STM32F427xx STM32F429xx
34/239 DocID024030 Rev 10
3.21 V
BAT
operation
The V
BAT
pin allows to power the device V
BAT
domain from an external battery, an external
supercapacitor, or from V
DD
when no external battery and an external supercapacitor are
present.
V
BAT
operation is activated when V
DD
is not present.
The V
BAT
pin supplies the RTC, the backup registers and the backup SRAM.
Note: When the microcontroller is supplied from V
BAT
, external interrupts and RTC alarm/events
do not exit it from V
BAT
operation.
When PDR_ON pin is not connected to V
DD
(Internal Reset OFF), the V
BAT
functionality is
no more available and V
BAT
pin should be connected to VDD.
3.22 Timers and watchdogs
The devices include two advanced-control timers, eight general-purpose timers, two basic
timers and two watchdog timers.
All timer counters can be frozen in debug mode.
Table 6 compares the features of the advanced-control, general-purpose and basic timers.
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