HA16117F Series

16

Setting of

RES Timing and Watchdog Frequency Range

Different MPUs have different

RES timing requirements. The minimum reset time (t

on (rise of 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

Parameters

Item

Symbol

CR (pin 4)

CF (pin 3)

K (pin 8) *

1

Power-on reset time

t

ON

q

Reset-clock off time

t

OFF

qv *

2

q

Reset low time

t

RL

q

Reset high time

t

RH

qq

Watchdog frequency high

f

H

qq

Watchdog frequency low

f

L

qqq

Notes: 1. K = R

2. Variability of t

The variability

∆t

3.3 (M

Ω) × C

3. External constants should be selected with reference to the formulas in tables 1 and 2.

Table 1

Calculation of

RES Output Timing

Item

Formula

Notes

t

400 (

Ω) × C

t

t

1.99

× t

t

0.5

× t

t

t

1.6 (V)

K

× 31 (µA) − 15.8 (µA)

× C

3

t

≈ t

Table 2

Calculation of Watchdog Frequency Range

Item

Formula

f

1

500 (

Ω) × C

t

t

×

f

1

1.7 (M

Ω) × C

t

t

1

t

or

Whichever is larger