HA16117FPA RENESAS [Renesas Technology Corp], HA16117FPA Datasheet - Page 17

• Manufacturer Part Number: HA16117FPA
• Description: CMOS Watchdog Timer
• Manufacturer: RENESAS [Renesas Technology Corp]

HA16117F Series
Selection of External Constants
If the reset duration necessary for the MPU to operate reliably at power-on is known, there is a simple procedure for
selecting external constants, starting from the power-on reset time (t
Application Example
Rev.3.00 Jun 15, 2005 page 17 of 30
START
Battery
Decide reset
Select external
low time (t
constant C
Set power-on
reset time t
RL
R
regulator
Figure 4 Procedure for Selecting External Constants
)
0.01 F
5 V
ON
C
0.1 F
F
C
R
Decide reset-clock
Select external
off time (t
constants R
SW
Set reset high
time t
V
P-RUN
C
C
CC
F
R
RH
OFF
HA16117F
1
)
and R
GND
2
ACC
RES
Tadj
Select external
constant C
ON
).
R
510 k
R
750 k
F
1
2
Check watchdog
frequency range
f
RES
H
V
CC
and f
Microprocessor
system
L
PORT GND
External
constant
values