Display Control Instructions

The display is controlled by writing data to the instruction register and the 13 data registers. The instruction register and

the data registers are differentiated using the RS signal. First, with RS set to 1 the application writes 8-bit data to the

instruction register and specifies the code for the data register. Then, with RS set to 0, the application writes 8-bit data to

the data register, and the specified instruction is executed. Note that another instruction cannot be written while the

previous instruction is executing. Since the busy flag is set during this period, applications must verify that the busy flag

is 0 before writing an instruction. However, after a data read instruction or a data write instruction, the microcontroller

may execute the next instruction without checking the busy flag after the maximum value of the read cycle or write cycle

elapses, respectively

• Mode control

Applications specify the mode control register by writing 00H to the instruction register.

(The form "00H" is used to express values in hexadecimal.)

• Character pitch setting

VP indicates the number of dots in the vertical direction per character. Applications should determine this value based

on the desired vertical separation between characters. This setting is only meaningful in character display mode, and is

ignored in graphics mode.

In character display mode, HP indicates the number of dots in the horizontal direction per character, and also includes

the gap between the current character and the character displayed to the right. In graphics mode, HP indicates the

number of bits displayed from each byte of display data from RAM.

HP can be set to one of three values.

No. 5946-9/18

LC7982A

Register

R/W

RS

DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

Instruction register

0

1

0

0

0

0

0

0

0

0

Mode control register

0

0

0

0

Mode data

DB5 DB4 DB3 DB2 DB1 DB0

Cursor/blinking

CG

Graphics/character display

0

0

Cursor off

0

1

0

Cursor on

1

0

Cursor off/character blinking

1

1

0

Cursor blinking

1/0

1/0

0

0

Cursor off

0

1

1

Cursor on

1

0

Cursor off/character blinking

1

1

Cursor blinking

0

0

1

0

Character display

mode

Graphics mode

Display

on/of

Master/

slave

Blinking Cursor Mode

Internal/

external

CG

1: Master mode

0: Slave mode

1: Display on

0: Display off

Register

R/W

RS

DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

Instruction register

0

1

0

0

0

0

0

0

0

1

Character pitch register

0

0

(VP - 1) binary

0

(HP - 1) binary

Hp

DB2 DB1 DB0

Setting

6

1

0

1

Horizontal character pitch of 6 dots

7

1

1

0

Horizontal character pitch of 7 dots

8

1

1

1

Horizontal character pitch of 8 dots