HD66420 Datasheet, PDF (32/52 Pages) Hitachi Semiconductor – (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD)

HD66420
Blink Function
The HD66420 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 18. 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 19).
Blink start
line (R6)
Blink end
line (R7)
LCD
Blink registers
0 0 0 0 0 0 1 1 1 1 1 0 0 0 0 1 0 0 01
DDD DDD DDDDDDDDDDDDDD
BBB BBB BBBBBBBBBBBBBB
765 432 107 65 432 103 210
R8
R9
R10
Figure 18 Blink Area Designation by Blink Control Registers
Blink area
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