Description
STM32F405xx, STM32F407xx
The device also features an embedded programmable voltage detector (PVD) that monitors
the V /V
power supply and compares it to the V
threshold. An interrupt can be
DD DDA
PVD
generated when V /V
drops below the V
threshold and/or when V /V
is
DD DDA
PVD
DD DDA
higher than the V
threshold. The interrupt service routine can then generate a warning
PVD
message and/or put the MCU into a safe state. The PVD is enabled by software.
Internal reset OFF
This feature is available only on packages featuring the PDR_ON pin. The internal power-on
reset (POR) / power-down reset (PDR) circuitry is disabled with the PDR_ON pin.
An external power supply supervisor should monitor V and should maintain the device in
DD
reset mode as long as V is below a specified threshold. PDR_ON should be connected to
DD
this external power supply supervisor. Refer to Figure 7: Power supply supervisor
interconnection with internal reset OFF.
Figure 7. Power supply supervisor interconnection with internal reset OFF
VDD
External VDD power supply supervisor
Ext. reset controller active when
VDD < 1.7 V or 1.8 V (1)
PDR_ON
Application reset
signal (optional)
NRST
VDD
MS31383V3
1. PDR = 1.7 V for reduce temperature range; PDR = 1.8 V for all temperature range.
The V specified threshold, below which the device must be maintained under reset, is
DD
1.8 V (see Figure 7). This supply voltage can drop to 1.7 V when the device operates in the
0 to 70 °C temperature range.
A comprehensive set of power-saving mode allows to design low-power applications.
When the internal reset is OFF, the following integrated features are no more supported:
•
•
•
•
The integrated power-on reset (POR) / power-down reset (PDR) circuitry is disabled
The brownout reset (BOR) circuitry is disabled
The embedded programmable voltage detector (PVD) is disabled
V
functionality is no more available and V
pin should be connected to V
BAT DD
BAT
All packages, except for the LQFP64 and LQFP100, allow to disable the internal reset
through the PDR_ON signal.
24/185
DocID022152 Rev 4