ST7265X datasheet(32/166 Pages) STMICROELECTRONICS

Part #	ST7265X

Description	LOW-POWER, FULL-SPEED USB 8-BIT MCU WITH 32K FLASH, 5K RAM, FLASH CARD I/F, TIMER, PWM, ADC, I2C, SPI

PDF	166 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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ST7265x

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6.3 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 VDD supply voltage is below a VIT- reference

value. This means that it secures the power-up as

well as the power-down, keeping the ST7 in reset.

The VIT- reference value for a voltage drop is lower

than the VIT+ reference value for power-on in order

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

VDD is below:

–VIT+ when VDD is rising

–VIT- when VDD is falling

The LVD function is illustrated in Figure 22.

During a Low Voltage Detector Reset, the RESET

pin is held low, thus permitting the MCU to reset

other devices.

Figure 22. Low Voltage Detector vs Reset

VDD

VIT+(LVD)

RESET

VIT-(LVD)

Vhyst

ST7265X Datasheet(PDF) 32 Page - STMicroelectronics