ST7FMC1K2B3 STMICROELECTRONICS [STMicroelectronics], ST7FMC1K2B3 Datasheet - Page 32

• Manufacturer Part Number: ST7FMC1K2B3
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST7MC1xx/ST7MC2xx
6.3 SYSTEM INTEGRITY MANAGEMENT (SI)
The System Integrity Management block contains
the Low Voltage Detector (LVD), Auxiliary Voltage
Detector (AVD) and Clock Security System (CSS)
functions. It is managed by the SICSR register.
Note: A reset can also be triggered following the
detection of an illegal opcode or prebyte code. Re-
fer to
tails.
6.3.1 Low Voltage Detector (LVD)
The Low Voltage Detector function (LVD) gener-
ates a static reset when the V
below a V
secures the power-up as well as the power-down
keeping the ST7 in reset.
The V
than the V
to avoid a parasitic reset when the MCU starts run-
ning and sinks current on the supply (hysteresis).
The LVD Reset circuitry generates a reset when
V
Figure 17. Low Voltage Detector vs Reset
32/309
1
DD
– V
– V
RESET
is below:
IT-
IT+
IT-
section 11.2.1 on page 244
V
V
reference value for a voltage drop is lower
when V
when V
IT-
IT+
IT+
IT-
reference value for power-on in order
reference value. This means that it
V
DD
DD
DD
is falling
is rising
DD
supply voltage is
for further de-
The LVD function is illustrated in
Provided the minimum V
the oscillator frequency) is above V
can only be in two modes:
In these conditions, secure operation is always en-
sured for the application without the need for ex-
ternal reset hardware.
During a Low Voltage Detector Reset, the RESET
pin is held low, thus permitting the MCU to reset
other devices.
Notes:
The LVD allows the device to be used without any
external RESET circuitry.
The LVD is an optional function which can be se-
lected by option byte.
It is recommended to make sure that the V
ply voltage rises monotonously when the device is
exiting from Reset, to ensure the application func-
tions properly.
V
– under full software control
– in static safe reset
hys
DD
value (guaranteed for
Figure
IT-
, the MCU
17.
DD
sup-