No. 5731-13/23

LC74788, 74788M, 74788JM

COMMAND4 (Display control setup command)

• First byte

DA

Register

Contents

Notes

0 to 7

State

Function

7

—

1

6

—

1

Command 4 identification code.

5

—

0

Display character data write setup.

4

—

0

3

TSTMOD

0

Normal operating mode

This bit must be set to 0.

1

Test mode

2

RAMERS

0

1

Erase display RAM. (The RAM data is set to FF hexadecimal.)

1

OSCSTP

0

Do not stop the crystal and LC oscillators.

1

Stop the crystal and LC oscillators.

0

SYSRST

0

1

Reset all registers and turn display off.

• Second byte

DA

Register

Contents

Notes

0 to 7

State

Function

7

—

0

Second byte identification bit

6

BLK2

0

Character display area

Specifies the size for complete fill in

1

Video display area

5

BLK1

0

1

Changes the blanking size

4

BLK0

0

1

3

BK1

0

Blinking period: About 0.5 s

Switches the blinking period

1

Blinking period: About 1.0 s

2

BK0

0

Blinking off

1

Blinking on

1

RV

0

Reverse video off

1

Reverse video on

0

DSPON

0

Character display off

1

Character display on

Note: All registers are set to 0 when the LC74788/M/JM is reset by the RST pin.

Blinking in reverse video mode switches the display between

normal character display and reverse video display.

Erasing RAM takes about 500 µs. (This operation

must be executed in the DSPOFF state.)

Valid in external synchronization mode when

character display is off.

The registers are reset when the CS pin is low, and

the reset state is cleared when CS is set high.

BLK0

0

1

BLK1

0

Blanking off

Character size

1

Frame size

Complete fill in