hd66421 Renesas Electronics Corporation., hd66421 Datasheet - Page 29

• Manufacturer Part Number: hd66421
• Description: Ram-provided 160 Channel 4-level Grey Scale Driver For Dot Matrix Graphics Lcd
• Manufacturer: Renesas Electronics Corporation.

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.
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).
Preliminary
Blink registers
Blink end
line (R7)
Blink start
line (R6)
Display start raster = 0
Blink start raster
Blink end raster
For
Figure 25 Blink Area Designation by Blink Control Registers
example,
D
B
7
0 0 0 0 0 0 1 1 1 1 1 0 0 0 0 1
D
B
6
Figure 26 Scrolling Blink Area
D
B
5
= 0
= H'F
D
B
4
R8
when
D
B
3
D
B
2
D
B
1
the
D
B
0
D
B
7
D
B
6
frame
D
B
5
D
B
4
R9
D
B
3
29
D
B
2
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).
LCD
D
B
1
D
B
0
Display start raster = H'5
Blink start raster
Blink end raster
D
B
3
0 0 0 1
D
B
2
R10
D
B
1
D
B
0
= H'5
= H'F
Blink area
Rev. 1.1E '99.02.10
HD66421