HT46C64 datasheet(25/48 Pages) HOLTEK

25 / 48 page

HT46R64/HT46C64

Rev. 1.80

February 14, 2006

LCD Display Memory

The device provides an area of embedded data memory

for LCD display. This area is located from 40H to 60H of

the RAM at Bank 1. Bank pointer (BP; located at 04H of

the RAM) is the switch between the RAM and the LCD

display memory. When the BP is set as

²1², any data

written into 40H~60H will effect the LCD display. When

the BP is cleared to

²0² or ²1², any data written into

40H~60H means to access the general purpose data

memory. The LCD display memory can be read and writ-

ten to only by indirect addressing mode using MP1.

When data is written into the display data area, it is auto-

matically read by the LCD driver which then generates

the corresponding LCD driving signals. To turn the dis-

play on or off, a

²1² or a ²0² is written to the correspond-

ing bit of the display memory, respectively. The figure

illustrates the mapping between the display memory

and LCD pattern for the device.

LCD Driver Output

The output number of the device LCD driver can be 33

´2

or 33

´3or32´4 by option (i.e., 1/2 duty, 1/3 duty or 1/4

duty). The bias type LCD driver can be

²R² type or ²C²

type. If the

²R² bias type is selected, no external capaci-

tor is required. If the

²C² bias type is selected, a capaci-

tor mounted between C1 and C2 pins is needed. The

LCD driver bias voltage can be 1/2 bias or 1/3 bias by

option. If 1/2 bias is selected, a capacitor mounted be-

tween V2 pin and ground is required. If 1/3 bias is se-

lected, two capacitors are needed for V1 and V2 pins.

Refer to application diagram.

4 0 H

C O M

S E G M E N T

4 1 H

4 2 H

4 3 H

5 E H 5 F H

6 0 H

B i t

3 0

3 1

3 2

Display Memory

C O M 0

C O M 1

C O M 2

C O M 3

L C D s e g m e n t s O N

C O M 2 s i d e l i g h t e d

V A

V B

V C

V S S

V A

V B

V C

V A

V B

V C

V A

V B

V C

V A

V B

V C

N o t e : 1 / 4 d u t y , 1 / 3 b i a s , C t y p e : " V A " 3 / 2 V L C D , " V B " V L C D , " V C " 1 / 2 V L C D

1 / 4 d u t y , 1 / 3 b i a s , R t y p e : " V A " V L C D , " V B " 2 / 3 V L C D , " V C " 1 / 3 V L C D

LCD Driver Output

HT46C64 Datasheet(PDF) 25 Page - Holtek Semiconductor Inc

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