HT46R74D-1 Holtek Semiconductor, HT46R74D-1 Datasheet - Page 27

• Manufacturer Part Number: HT46R74D-1
• Description: Dual Slope A/D Type MCU
• Manufacturer: Holtek Semiconductor

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LCD Display Memory
The device provides an area of embedded data memory
for the LCD display. This area is located at 40H to 4FH in
Bank 1 of the Data Memory. The bank pointer BP, en-
ables either the General Purpose Data Memory or LCD
Memory to be chosen. When BP is set to 1 , any data
written into location range 40H~4FH will affect the LCD
display. When the BP is cleared to 0 , any data written
into 40H~4FH will access the general purpose data
memory. The LCD display memory can be read and writ-
ten to only indirectly using 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 1 or
a 0 is written to the corresponding bit of the display
memory, respectively. The figure illustrates the mapping
between the display memory and LCD pattern for the
device.
The LCD clock frequency is determined by configuration
options, and has a division ratio range of fs/2
Rev. 1.10
LCD Driver Output (1/3 Duty, 1/2 Duty, R Type)
2
~fs/2
8
.
27
The LCD clock source frequency should be chosen to
be as close as possible to 4kHz.
Note that the LCD frequency is controlled by configura-
tion options, which select the internal division ratio.
LCD Driver Output
The output number of the device LCD driver can be
16 2, 16 3 or 15 4 by configuration option (i.e., 1/2, 1/3
or 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-
C type. If the R bias type is selected, no external ca-
Display Memory
HT46R74D-1
January 11, 2007