ST STM32F40 Series User Manual

RM0090 Power controller (PWR)
Doc ID 018909 Rev 4 94/1422
5.2 Power supply supervisor
5.2.1 Power-on reset (POR)/power-down reset (PDR)
The device has an integrated POR/PDR circuitry that allows proper operation starting from
to 1.8 V.
The device remains in Reset mode when V
DD
/V
DDA
is below a specified threshold,
V
POR/PDR
, without the need for an external reset circuit. For more details concerning the
power on/power-down reset threshold, refer to the electrical characteristics of the datasheet.
Figure 9. Power-on reset/power-down reset waveform
5.2.2 Brownout reset (BOR)
During power on, the Brownout reset (BOR) keeps the device under reset until the supply
voltage reaches the specified V
BOR
threshold.
V
BOR
is configured through device option bytes. By default, BOR is off. 4 programmable
V
BOR
thresholds can be selected.
● BOR off (V
BOR0
): reset threshold level for 1.8 to 2.10 V voltage range
● BOR Level 1 (V
BOR1
): reset threshold level for 2.10 to 2.40 V voltage range
● BOR Level 2 (V
BOR2
): reset threshold level for 2.40 to 2.70 V voltage range
● BOR Level 3 (V
BOR3
): reset threshold level for 2.70 to 3.60 V voltage range
When the supply voltage (V
DD
) drops below the selected V
BOR
threshold, a device reset is
generated.
BOR can be disabled by programming the device option bytes. To disable the BOR function,
V
DD
must have been higher than V
BOR0
to start the device option byte programming
sequence. The power-down is then monitored by the PDR (see Section 5.2.1: Power-on
reset (POR)/power-down reset (PDR))
VDD/VDDA
40 mV
hysteresis
PDR
PDR
MS30431V1
Reset
Temporization
tRSTTEMPO

ST STM32F40 Series Specifications

General

Brand	ST
Model	STM32F40 Series
Category	Microcontrollers
Language	English