Casio CTK-411, Service Manual

— 5 —

Pin No.

Terminal

In/Out

Function

74 ~ 77

DB4 ~ DB7

Out

Data bus for the LCD driver

78

NC9

—

Not used

79

LVCC

In

+5 V source

80 ~ 84

KO8 ~ KO12

Out

Terminals for button scan signal

85 ~ 87

P65 ~ P67

—

Not used

88

RS

Out

Control signal for the LCD driver

89

R/W

Out

Read/Write signal for the LCD driver

90

E

Out

Chip enable signal for the LCD driver

91 ~ 95

P73 ~ P77

—

Not used

96

LGND

In

Ground source

97, 100

MA18, MA15

Out

Address bus

LCD DRIVER (LSI3: KS0066U-10B)

The LCD driver can drive a dot matrix LCD having 40 segment and 16 common lines. The LSI contains 240
graphic symbols in the built-in character generator ROM, and stores 80 characters in the built-in display data
RAM. In accordance with command from the CPU, the LSI is capable of displaying up to 16 characters
simultaneously. The following table shows the pin functions of LSI3.

Pin No.

Terminal

In/Out

Function

1 ~ 22,

SEG1 ~ SEG40

Out

Segment signal output

63 ~ 80

23

VSS

—

GND (0 V) source

Terminals for the built-in clock pulse generator. The

24, 25

OSC1, OSC2

In/Out

external resistor connected determines the oscillation
frequency.

LCD drive voltage input.

26 ~ 30

V1 ~ V5

In

Those voltages are used for generating the stepped
pulse of the LCD drive signals.

31, 32

LP, XCLS

—

Not used

33

VDD

In

DVDD (+5 V) source

34, 35

FR, DO

—

Not used

36

RS

In

Data/command determination terminal.
High: data, Low: command

37

R/W

In

Read/Write terminal. High: read, Low: write

Chip enable signal.

38

E

In

High: enable, the writing is done at fall edge.
Low: disenable

39 ~ 42

DB0 ~ DB3

—

Not used. Connected to GND (0 V)

43 ~ 46

DB4 ~ DB7

In/Out

Data bus

47 ~ 62

COM1 ~ COM16

Out

Common signal/output