HT46C65 Holtek Semiconductor, HT46C65 Datasheet - Page 25

• Manufacturer Part Number: HT46C65
• Description: A/D with LCD Type 8-Bit MCU
• Manufacturer: Holtek Semiconductor

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 1 , any data
written into 40H~68H will effect the LCD display. When
the BP is cleared to 0 or 2 , 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 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
41 2 or 41 3 or 40 4 by option (i.e., 1/2 duty, 1/3 duty or
Rev. 1.80
LCD Driver Output
25
1/4 duty). The bias type LCD driver can be R type or
pacitor is required. If the C 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.
C type. If the R bias type is selected, no external ca-
Display Memory
HT46R65/HT46C65
July 14, 2005