ST STM32L4+ Series Reference Manual page 194

Power control (PWR)
5.2.3 Peripheral Voltage Monitoring (PVM)
Only V
DD
functions. The other supplies (V
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
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
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
available without enabling any Peripheral Voltage Monitoring.
•
If these supplies are independent from V
can be enabled to confirm whether the supply is present or not.
The following sequence must be done before using the USB OTG peripheral:
1. If V
DDUSB
a)
b)
c)
d)
2. Set the USV bit in the
power isolation.
The following sequence must be done before using any I/O from PG[15:2]:
194/2301
is monitored by default, as it is the only supply required for all system-related
PVM Power supply
PVM1
PVM2
PVM3
PVM4
DDA
is independent from V
Enable the PVM1 by setting PVME1 bit in the
(PWR_CR2).
Wait for the PVM1 wakeup time
Wait until PVMO1 bit is cleared in the
Optional: Disable the PVM1 for consumption saving.
Power control register 2 (PWR_CR2)
, V and V
DDA DDIO2 DDUSB
Table 25. PVM features
PVM threshold
V V
DDUSB PVM1
V V
DDIO2 PVM2
V V
DDA PVM3
V V
DDA PVM4
, V and V
DDIO2 DDUSB
, the application should assume they are
DD
, the Peripheral Voltage Monitoring (PVM)
DD
:
DD
Power status register 2
RM0432 Rev 6
) can be independent from V
(around 1.2 V)
(around 0.9 V)
(around 1.65 V)
(around 2.2 V)
) are not considered as present by
Power control register 2
(PWR_SR2).
to remove the V
RM0432
DD
and
PVMx
EXTI line
35
36
37
38
DDUSB