hd66421 Renesas Electronics Corporation., hd66421 Datasheet - Page 40

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

Contrast Control and LCD Alternative Drive
Cycle Register (R16): The contrast control
register (figure 44) designates the contrast level of
LCD display. These bits change the voltage which
is supplied to LCD drivers.
Table 9 Grayscale Levels
GP14 GP13 GP12 GP11 GP10
GP24 GP23 GP22 GP21 GP20
GP34 GP33 GP32 GP31 GP30
GP44 GP43 GP42 GP41 GP40
Preliminary
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 10 LCD alternative drive cycle
CM1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Set value
Data bit
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
CM0
0
0
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Figure 44 Contrast Control register (R16)
7
Alternative
Cycle
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Frame
7 lines
11 lines
13 lines
CM1
6
Gray scale
Level
10/31
11/31
12/31
13/31
14/31
15/31
1/31
2/31
3/31
4/31
5/31
6/31
7/31
8/31
9/31
CM0
5
0
40
CC4
4
The
designates the number of lines that LCD drive
outputs are alternated.
Data bits 7 is unused; they should be set to 0
when written to.
GP14 GP13 GP12 GP11 GP10
GP24 GP23 GP22 GP21 GP20
GP34 GP33 GP32 GP31 GP30
GP44 GP43 GP42 GP41 GP40
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
CC3
LCD
3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
CC2
2
alternative
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
CC1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
CC0
drive
0
Rev. 1.1E '99.02.10
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
cycle
HD66421
Gray scale
Level
16/31
17/31
18/31
19/31
20/31
21/31
22/31
23/31
24/31
25/31
26/31
27/31
28/31
29/31
30/31
register
1