4513_03 Datasheet, PDF (65/210 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCOMPUTER

HARDWARE
FUNCTION BLOCK OPERATIONS
VOLTAGE DROP DETECTION CIRCUIT
The built-in voltage drop detection circuit is designed to detect a
drop in voltage and to reset the microcomputer if the supply voltage
drops below a set value.
RESET pin
Internal reset signal
Voltage drop detection circuit
Watchdog timer output
WEF
Note: The output structure of RESET pin is N-channel open-drain.
Fig. 36 Voltage drop detection reset circuit
VDD
VRST (detection voltage)
Voltage drop detection
circuit output
RESET pin
The microcomputer starts
operation after f(XIN) is counted
16892 to 16895 times.
Notes 1: Pull-up RESET pin externally.
2: Refer to the voltage drop detection circuit in the electrical characteristics
for the rating value of VRST (detection voltage).
Fig. 37 Voltage drop detection circuit operation waveform
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4513/4514 Group User’s Manual