HD66421 Datasheet, PDF (29/46 Pages) Hitachi Semiconductor – (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD)

Preliminary
Rev. 1.1E '99.02.10
HD66421
Blink Function
The HD66421 can blink a specified area on the
dot-matrix display. Blinking is achieved by
repeatedly turning on and off the specified area at
a frequency of one sixty-fourth the frame
frequency. For example, when the frame
frequency is 80 Hz. the area is turned on and off
every 0.8 seconds.
The area to be blinked can be designated by
specifying vertical and horizontal positions of the
area. The vertical position. or the rasters to be
blinked, are specified by the blink start raster
register (R6) and blink end raster register (R7).
The horizontal position, or the dots to be blinked
in the specified rasters, are specified by the blink
registers R8, R9 and R10 in an 8-dot group; each
data bit in the blink registers controls its
corresponding 8-dots group. The relationship
between the registers and blink area is shown in
figure 25. Setting the BLK bit to 1 in control
register 2 after setting the above registers starts
blinking the designated area. Note that since the
area to be blinked is designated absolutely with
respect to the display RAM, it will move along
with a scrolling display (figure 26).
Blink start
line (R6)
Blink end
line (R7)
LCD
Blink registers
00000011111000010001
DDDDDDDDDDDDDDDDDDDD
BBBBBBBBBBBBBBBBBBBB
76543210765432103210
R8
R9
R10
Blink area
Figure 25 Blink Area Designation by Blink Control Registers
Display start raster = 0
Blink start raster = 0
Blink end raster = H'F
Display start raster = H'5
Blink start raster = H'5
Blink end raster = H'F
Figure 26 Scrolling Blink Area
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