Power control (PWR) RM0351
140/1693 DocID024597 Rev 3
Figure 9. PVD thresholds
5.2.3 Peripheral Voltage Monitoring (PVM)
Only V
DD
is monitored by default, as it is the only supply required for all system-related
functions. The other supplies (V
DDA
, V
DDIO2
and V
DDUSB
) can be independent from V
DD
and can be monitored with four Peripheral Voltage Monitoring (PVM).
Each of the four PVMx (x=1, 2, 3, 4) is a comparator between a fixed threshold V
PVMx
and
the selected power supply. PVMOx flags indicate if the independent power supply is higher
or lower than the PVMx threshold: PVMOx flag is cleared when the supply voltage is above
the PVMx threshold, and is set when the supply voltage is below the PVMx threshold.
Each PVM output is connected to an EXTI line and can generate an interrupt if enabled
through the EXTI registers. The PVMx output interrupt is generated when the independent
power supply drops below the PVMx threshold and/or when it rises above the PVMx
threshold, depending on EXTI line rising/falling edge configuration.
Each PVM can remain active in Stop 0, Stop 1 and Stop 2 modes, and the PVM interrupt
can wake up from the Stop mode.
The independent supplies (V
DDA
, V
DDIO2
and V
DDUSB
) are not considered as present by
default, and a logical and electrical isolation is applied to ignore any information coming
from the peripherals supplied by these dedicated supplies.
• If these supplies are shorted externally to V
DD
, the application should assume they are
available without enabling any Peripheral Voltage Monitoring.
• If these supplies are independent from V
DD
, the Peripheral Voltage Monitoring (PVM)
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Table 18. PVM features
PVM Power supply PVM threshold EXTI line
PVM1 V
DDUSB
V
PVM1
(around 1.2 V) 35
PVM2 V
DDIO2
V
PVM2
(around 0.9 V) 36
PVM3 V
DDA
V
PVM3
(around 1.65 V) 37
PVM4 V
DDA
V
PVM4
(around 2.2 V) 38
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