HA16117FPA RENESAS [Renesas Technology Corp], HA16117FPA Datasheet - Page 16

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

HA16117F Series
Setting of RES Timing and Watchdog Frequency Range
Different MPUs have different RES timing requirements. The minimum reset time (t
V
RES timing waveform parameters must be selected according to the MPU. With the HA16117F the timing of the RES
output and the watchdog frequency range can both be set by external constants (C
Power-on reset time
Reset-clock off time
Reset low time
Reset high time
Watchdog frequency high
Watchdog frequency low
Notes: 1. K = R
Table 1
t
t
t
t
t
Table 2
f
f
Rev.3.00 Jun 15, 2005 page 16 of 30
ON
OFF
RL
SL
H
L
RH
CC
(Hz)
(MHz)
(ms)
(ms)
(ms)
(ms)
) is 20 ms for some MPUs and 100 ms for others.
(ms)
2. Variability of t
3. External constants should be selected with reference to the formulas in tables 1 and 2.
3.3 (M )
Calculation of RES Output Timing
Calculation of Watchdog Frequency Range
Item
Item
Item
2
/ (R
1
C
+ R
F
OFF
( F), so C
2
)
increases with increasing C
F
t
t
t
t
f
f
400 ( )
1.99
0.5
Whichever is larger
1.7 (M )
K
500 ( )
ON
OFF
RL
RH
H
L
t
0.01 ( F) is recommended.
OFF
Symbol
31 ( A)
t
(ms)
ON
t
RH
1
1.6 (V)
1
(ms)
C
(ms)
C
C
R
F
F
( F)
( F)
15.8 ( A)
( F)
Formula
F
. The variability t
t
t
RH
RH
t
CR (pin 4)
RH
(ms)
(ms) + t
(ms) + t
C
R
t
RL
( F)
(ms)
t
RL
RL
RL
(ms)
(ms)
(ms)
10
Formula
OFF
3
is approximately
or
Parameters
F
t
t
ON
RL
, C
CF (pin 3)
*
2
t
and t
OFF
ON
and t
R
, and K).
) required at power-on (rise of
1
(ms)
RH
OFF
can be set independently
can be set independently
10
Notes
3
K (pin 8) *
1