Datasheet

Functional overview STM32F412xE/G
26/193 DocID028087 Rev 4
3.18 Power supply supervisor
3.18.1 Internal reset ON
This feature is available for V
DD
operating voltage range 1.8 V to 3.6 V.
On packages embedding the PDR_ON pin, the power supply supervisor is enabled by
holding PDR_ON high. On the other package, the power supply supervisor is always
enabled.
The device has an integrated power-on reset (POR) / power-down reset (PDR) circuitry
coupled with a Brownout reset (BOR) circuitry. At power-on, POR is always active, and
ensures proper operation starting from 1.8 V. After the 1.8 V POR threshold level is
reached, the option byte loading process starts, either to confirm or modify default
thresholds, or to disable BOR permanently. Three BOR thresholds are available through
option bytes.
The device remains in reset mode when V
DD
is below a specified threshold, V
POR/PDR
or
V
BOR
, without the need for an external reset circuit.
The device also features an embedded programmable voltage detector (PVD) that monitors
the V
DD
/V
DDA
power supply and compares it to the V
PVD
threshold. An interrupt can be
generated when V
DD
/V
DDA
drops below the V
PVD
threshold and/or when V
DD
/V
DDA
is
higher than the V
PVD
threshold. The interrupt service routine can then generate a warning
message and/or put the MCU into a safe state. The PVD is enabled by software.
3.18.2 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 by setting the PDR_ON pin to
low.
An external power supply supervisor should monitor V
DD
and should set the device in reset
mode when V
DD
is below 1.7 V. NRST should be connected to this external power supply
supervisor. Refer to Figure 7: Power supply supervisor interconnection with internal reset
OFF.
Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.