Brownout Reset (Bor); Programmable Voltage Detector (Pvd); Figure 6. Bor Thresholds - ST STM32F207 Series Reference Manual

RM0033
4.2.2

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. Three
BOR
programmable V
BOR Level 3 (V
BOR Level 2 (V
BOR Level 1 (V
Note: For full details about BOR characteristics, refer to Section "Electrical characteristics" in the
device datasheet.
When the supply voltage (V
generated. The BOR can be disabled by programming the device option bytes. Therefore,
the power-on and power-down is then monitored by the POR/ PDR (see
Power-on reset (POR)/power-down reset
The BOR threshold hysteresis is ~100 mV (between the rising and the falling edge of the
supply voltage).
Reset
4.2.3

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
if V /V
DD DDA
the EXTI line16 and can generate an interrupt if enabled through the EXTI registers. The
PVD output interrupt can be generated when V
and/or when V
rising/falling edge configuration. As an example the service routine could perform
emergency shutdown tasks.
BOR
threshold levels can be selected:
BOR
). Brownout threshold level 3.
BOR3
). Brownout threshold level 2.
BOR2
). Brownout threshold level 1.
BOR1
) drops below the selected V
DD

Figure 6. BOR thresholds

V /V
DD DDA
PWR power control/status register
is higher or lower than the PVD threshold. This event is internally connected to
/V rises above the PVD threshold depending on EXTI line16
DD DDA
RM0033 Rev 9
threshold.
(PDR)).
BOR threshold
/V power supply by comparing it to a threshold
DD DDA
PWR power control register
/V drops below the PVD threshold
DD DDA
Power control (PWR)
threshold, a device reset is
BOR
Section 4.2.1:
(PWR_CR).
(PWR_CSR), to indicate
100 mV
hysteresis
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