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Reset circuit – Renesas M38C29T-ADF User Manual

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6. Reset Circuit


Figure 6.1 shows the reset circuit and its waveform. In this product, reset is cleared in about 100ms from the instant Vcc passes about
2.1V after having started from 0 V. When Vcc drops down to about 2.1V, reset turns effective.

Figure 6.1 Reset circuit and its waveform

By using SW5, the MCU can be reset manually.

Table 6.1 Function of SW5 (reset switch)

No. Name Function
SW5

RESET

This is the reset switch. Press down this switch to reset the MCU.

R 3

6. 8 K

C 5

0. 3 3 u F

R 4

10 K

R 5

1 0K

1

2

3

5

4

Vcc

IN

OUT

Vss

CD

M5195 7BL

S W4

I C3

MCU RE SET

TP3

RESET

td

t d

t d =

0 . 34 x CD (pF ) usec

1 .25V

H

L

Input volage
( IC3- 2-pin)

Output state

( IC3 - 5-pin )

CD

Detected power voltage (V )

Approx. 1. 25 x ( R3 + R4 ) / R4

Vcc