7220 Datasheet, PDF (126/303 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

FUNCTIONAL DESCRIPTION
2.15 Reset
2.15.3 Notes for poweron reset
When poweron reset, set the external reset circuit
so that the reset input voltage must be kept 0.6 V
or less until the power source voltage reaches
4.5 V after the power is turned on.
Set the external reset circuit so that the reset input
voltage must be kept 0.6 V or less when the power
source voltage falls 4.5 V after the power is turned
off.
Figures 2.15.5 to 2.15.7 show examples of external
reset circuit.
M37221M6-
XXXSP/FP
RESET ^VCC 0 V
Power source
voltage
4.5 V
Reset input
voltage
0V
Poweron
0.6 V
Fig. 2.15.5 Voltage at poweron reset
RESET
VCC
M37221M6-
XXXSP/FP
VSS
RESET
VCC
M37221M6-
XXXSP/FP
VSS
Fig. 2.15.6 Example of reset circuit (1)
Fig. 2.15.7 Example of reset circuit (2)
7220 Group User’s Manual
2-99