HT46R64 Holtek Semiconductor Inc., HT46R64 Datasheet - Page 25

• Manufacturer Part Number: HT46R64
• Description: Ht46r64/ht46c64 -- A/d With Lcd Type 8-bit Mcu
• Manufacturer: Holtek Semiconductor Inc.

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 1 , any data
written into 40H~60H will effect the LCD display. When
the BP is cleared to 0 or 1 , 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 1 or a 0 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 3 or 32 4 by option (i.e., 1/2 duty, 1/3 duty or 1/4
Rev. 1.80
LCD Driver Output
25
duty). The bias type LCD driver can be R type or C
type. If the R bias type is selected, no external capaci-
tor is required. If the C 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.
Display Memory
HT46R64/HT46C64
February 14, 2006