Инструкции По Обслуживанию для Canon fax basic 2000

FACSIMILE SYSTEM

6–20

For example, if button 23 is held down when KOUT2 becomes Low, KIN3

also becomes Low, and the OPCNT control IC detects that the button of

the KOUT2 row and the KIN3 line has been pressed.

Fig. 6-21   Button Detection Timing Chart 2

When the OPCNT control IC detects button input, that information is

relayed to the 

 by serial communications, and the command that

instructs whether to perform LCD display or light the LEDs is returned

from the MPU according to the button that was pressed.

Fig. 6-22   Flow of Data

H
L

H
L

H
L

H
L

OPCNT

control IC

Divided

clock

Button 23
is pressed.

KOUT7~KOUT0

0

1

2

3

4

5

6

7

8

8

KIN7~KIN0

7

6

5

4

3

2

1

0

+5V

KOUT0

KOUT1

KOUT2

KIN3

Button 3 is pressed.

Light LED.

System

controller

OPCNT

control IC

OPCNT board

Keyboard

SCNT board

CPU

LED