Holtek HT49RU80 Manual page 24

LCD Display Memory
The device provides an area of embedded data memory
for the LCD display. This area is located from 40H to
6FH in Bank 1 of the data memory. The bank pointer, BP,
is used to switch between the general purpose data
memory and the LCD display memory. When BP has the
value ²01H², any data written into the locations
40H~6FH will influence the LCD display. When BP is
cleared to ²00H², any data written into the locations
40H~6FH will access the general purpose data memory.
The LCD display memory can be read and written to
only using the indirect addressing mode using memory
pointer MP1. When data is written into the display data
area, it is automatically read by the LCD driver which
then generates the corresponding LCD driving signals.
To turn the display on or off, a ²1² or a ²0² is written to
the corresponding bit of the display memory, respec-
tively. The figure illustrates the mapping between the
display memory and the LCD pattern for the device.
LCD Driver Output
The output number of the LCD driver device can be
Rev. 1.10
48´2, 48´3 or 47´4 selected by configuration options,
i.e., 1/2 duty, 1/3 duty or 1/4 duty. There are two types of
biasing, ²R² type or ²C² type. If the ²R² bias type is se-
lected, no external capacitors are required. If the ²C²
bias type is selected, a capacitor mounted between C1
and C2 pins is required. If 1/2 bias is selected, a capaci-
tor mounted between the V2 pin and ground is required.
If 1/3 bias is selected, two capacitors are required to be
connected between the V1 and V2 pins and V
gested value of 0.1mF is recommended for all the ca-
pacitors.
LCD Driver Output
24
HT49RU80/HT49CU80
Display Memory
SS
March 2, 2007
. A sug-