Power Supply Supervisor; Power-On Reset (Por)/Power-Down Reset (Pdr); Figure 5. Power-On/Power-Down Reset Waveform - ST STM32F207 Series Reference Manual

Power control (PWR)
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 1.2 V domain (core, memories
and digital peripherals).
• In Stop mode the regulator supplies low power to the 1.2 V domain, preserving the
content of registers and internal SRAM.
•
In Standby mode, the regulator is powered down. The content of the registers and
SRAM are lost except for the Standby circuitry and the backup domain.
Note: Depending on the selected package, the voltage regulator can be deactivated. For more
details, refer to the Voltage regulator section in STM32F2xx datasheets.
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 1.8 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.
Reset
68/1381
, without the need for an external reset circuit. For more details concerning the

Figure 5. Power-on/power-down reset waveform

V /V
DD DDA
POR
/V is below a specified threshold,
DD DDA
40 mV
hysteresis
Temporization
t
RSTTEMPO
RM0033 Rev 9
RM0033
PDR