ST72C334N2B6 STMicroelectronics, ST72C334N2B6 Datasheet - Page 25

• Manufacturer Part Number: ST72C334N2B6
• Description: Microcontrollers (MCU) Flash 8K SPI/SCI
• Manufacturer: STMicroelectronics

Specifications of ST72C334N2B6

• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 8 KB
• Data Ram Size: 384 B
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 44
• Number Of Timers: 16 bit
• Operating Supply Voltage: 3.2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Package / Case: SDIP-56
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / Rohs Status: No

4.1 LOW VOLTAGE DETECTOR (LVD)
To allow the integration of power management
features in the application, the Low Voltage Detec-
tor function (LVD) generates a static reset when
the V
value. This means that it secures the power-up as
well as the power-down keeping the ST7 in reset.
The V
lower than the V
in order to avoid a parasitic reset when the MCU
starts running and sinks current on the supply
(hysteresis).
The LVD Reset circuitry generates a reset when
V
The LVD function is illustrated in the Figure 13.
Provided the minimum V
the oscillator frequency) is below V
can only be in two modes:
Figure 13. Low Voltage Detector vs Reset
DD
– V
– V
– under full software control
– in static safe reset
RESET
is below:
DD
LVDr
LVDf
LVDf
V
V
LVDf
LVDr
supply voltage is below a V
when V
when V
reference value for a voltage drop is
V
DD
LVDr
DD
DD
reference value for power-on
is falling
is rising
DD
value (guaranteed for
LVDf
LVDf
, the MCU
reference
HYSTE RESIS
V
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:
1) the LVD allows the device to be used without any exter-
nal RESET circuitry.
2) three different reference levels are selectable through
the OPTION BYTE according to the application require-
ment.
LVD application note
Application software can detect a reset caused by
the LVD by reading the LVDRF bit in the CRSR
register.
This bit is set by hardware when a LVD reset is
generated and cleared by software (writing zero).
LVDhyst
ST72334J/N, ST72314J/N, ST72124J
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