Voltage Regulator; Power Supply Supervisor; Power On Reset (Por)/Power Down Reset (Pdr) - ST STM32F100 Series Reference Manual

Power control (PWR)
When the backup domain is supplied by V
following functions are available:
•
PC14 and PC15 can be used as either GPIO or LSE pins
•
PC13 can be used as GPIO, TAMPER pin, RTC Calibration Clock, RTC Alarm or
second output (refer to
Note: Because the switch only sinks a limited amount of current (3 mA), the use of GPIOs PC13 to
PC15 in output mode is restricted: the speed has to be limited to 2 MHz with a maximum
load of 30 pF and these IOs must not be used as a current source (e.g. to drive a LED).
When the backup domain is supplied by V
V is not present), the following functions are available:
DD
•
PC14 and PC15 can be used as LSE pins only
•
PC13 can be used as TAMPER pin, RTC Alarm or Second output (refer to
Section 5.4.2: RTC clock calibration register
4.1.3

Voltage regulator

The voltage regulator is always enabled after Reset. It works in three different modes
depending on the application modes.
•
In Run mode, the regulator supplies full power to the 1.8 V domain (core, memories
and digital peripherals).
•
In Stop mode the regulator supplies low-power to the 1.8 V domain, preserving
contents of registers and SRAM
• In Standby mode, the regulator is powered off. The contents of the registers and SRAM
are lost except for the Standby circuitry and the Backup Domain.
4.2

Power supply supervisor

4.2.1

Power on reset (POR)/power down reset (PDR)

The device has an integrated POR/PDR circuitry that allows proper operation starting
from/down to 2 V.
The device remains in Reset mode when V
V
POR/PDR
power on/power down reset threshold, refer to the electrical characteristics of the datasheet.
52/709
Section 5: Backup registers
, without the need for an external reset circuit. For more details concerning the
(analog switch connected to V
DD
(analog switch connected to V
BAT
(BKP_RTCCR)).
/V is below a specified threshold,
DD DDA
RM0041 Rev 6
DD
(BKP))
BAT
RM0041
), the
because