Brownout Reset (Bor); Programmable Voltage Detector (Pvd); Figure 11. Bor Thresholds - ST STM32F446 Series Reference Manual

RM0390
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
V is configured through device option bytes. By default, BOR is off. 3 programmable
BOR
V threshold levels can be selected:
BOR
•
BOR Level 3 (VBOR3). Brownout threshold level 3.
•
BOR Level 2 (VBOR2). Brownout threshold level 2.
•
BOR Level 1 (VBOR1). Brownout threshold level 1.
Note: For full details about BOR characteristics, refer to the "Electrical characteristics" section in
the device datasheet.
When the supply voltage (V
generated.
The BOR can be disabled by programming the device option bytes. In this case, the
power-on and power-down is then monitored by the POR/ PDR (see
on reset (POR)/power-down reset
The BOR threshold hysteresis is ~100 mV (between the rising and the falling edge of the
supply voltage).
5.2.3

Programmable voltage detector (PVD)

You can use the PVD to monitor the V
selected by the PLS[2:0] bits in the
The PVD is enabled by setting the PVDE bit.
A PVDO flag is available, in the
(PWR_CSR), to indicate if V
threshold.
BOR
) drops below the selected V
DD
(PDR)).

Figure 11. BOR thresholds

power supply by comparing it to a threshold
DD
Section 5.4.1: PWR power control register
Section 5.4.2: PWR power control/status register
is higher or lower than the PVD threshold. This event is
DD
RM0390 Rev 4
Power controller (PWR)
threshold, a device reset is
BOR
Section 5.2.1: Power-
(PWR_CR).
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