} COMMAND 5 (Synchronizing signal control setup command)

First byte

Second byte

Note: All these registers are set to 0 by a reset due to the RST pin.

Display Screen Organization

The display screen consists of 10 lines of 24 characters each. Thus the maximum number of characters that can be

displayed is 240 characters. However, the maximum number of characters that can be displayed may be fewer than 240

when characters are enlarged. The display memory address consists of a line address (with values from 0 to 9 decimal),

and a column (character position) address (with values from 0 to 23 decimal).

No. 4247-10/14

LC74730M

Register content

DA0 to DA7

Register name

State

Function

Note

7

—

0

Second byte identification bit

6

—

0

5

—

0

4

—

0

3

SN3

0

1

2

SN2

0

1

1

SN1

0

1

0

SN0

0

1

External synchronizing signal detection

control

SN3 SN2 SN1 SN0

Number of times HSYNC detected

0

0

0

0

Not detected

0

0

0

1

16 times

0

0

1

0

32 times

0

1

0

0

64 times

1

0

0

0

128 times

Register content

DA0 to DA7

Register name

State

Function

Note

7

—

1

6

—

1

Command 5 identification code

5

—

0

Sets up control of the synchronizing signals

4

—

1

0

3

PH1

1

0

2

PH0

1

1

BCL

0

Background color displayed.

Valid only in internal synchronization

1

No background color (only the background level is set).

mode

0

INT

0

External synchronization

Switches between internal and external

1

Internal synchronization

synchronization.

Sets the background color

(one of 4 colors).

There is only one background color

(blue) in PAL-M mode.

PHASE1 PHASE0

Background color (phase)

0

0

π/2

0

1

π

1

0

3

π/2

1

1

In phase