HT46R65 datasheet(25/48 Pages) HOLTEK

25 / 48 page

HT46R65/HT46C65

Rev. 1.80

July 14, 2005

LCD Display Memory

The device provides an area of embedded data memory

for LCD display. This area is located from 40H to 68H 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~68H will effect the LCD display. When

the BP is cleared to

²0² or ²2², any data written into

40H~68H means to access the general purpose data

memory. The LCD display memory can be read and

written 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

´2or41´3or40´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 ca-

pacitor is required. If the

²C² bias type is selected, a ca-

pacitor 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

between 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

6 6 H

6 7 H

6 8 H

B i t

3 8

3 9

4 0

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

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