EP7211 Datasheet, PDF (109/166 Pages) Cirrus Logic – HIGH-PERFORMANCE ULTRA-LOW-POWER SYSTEM-ON-CHIP WITH LCD CONTROLLER

EP7211
High-Performance Ultra-Low-Power System-on-Chip with LCD Controller
5.10.2 PALLSW Least Significant Word — LCD Palette Register
ADDRESS: 0x8000.0580
.
31–28
27–24
23–20
19–16
15–12
11–8
7–4
3–0
Grey scale
value for pixel
value 7
Grey scale
value for
pixel value 6
Grey scale
value for
pixel value 5
Grey scale
value for
pixel value 4
Grey scale
value for
pixel value 3
Grey scale
value for
pixel value 2
Grey scale
value for
pixel value 1
Grey scale
value for
pixel value 0
The least and most significant word LCD palette registers make up a 64-bit read/write register which
maps the logical pixel value to a physical grey scale level. The 64-bit register is made up of 16 x 4-
bit nibbles, each nibble defines the grey scale level associated with the appropriate pixel value. If the
LCD controller is operating in two bits per pixel, only the lower 4 nibbles are valid (D15–D0 in the
least significant word).
5.10.3 PALMSW Most Significant Word — LCD Palette Register
ADDRESS: 0x8000.0540
See PALLSW description.
31–28
Grey scale
value for pixel
value 15
27–24
Grey scale
value for
pixel value
14
23–20
Grey scale
value for
pixel value
13
19–16
Grey scale
value for
pixel value
12
15–12
Grey scale
value for
pixel value
11
11–8
Grey scale
value for
pixel value
10
7–4
3–0
Grey scale
value for
pixel value 9
Grey scale
value for
pixel value 8
The actual physical color and pixel duty ratio for the grey scale values are shown in the table above.
Note that colors 8–15 are the inverse of colors 7–0 respectively. This means that colors 7 and 8 are
identical. The steps in the grey scale are non-linear, but have been chosen to give a close
approximation to perceived linear grey scales. The is due to the eye being more sensitive to changes
in grey level close to 50% grey.
Table 5-12. Grey Scale Value to Color Mapping
Grey Scale Value
0
1
2
3
4
5
6
7
Duty Cycle
0
1/9
1/5
4/15
3/9
2/5
4/9
1/2
% Pixels Lit
0%
11.1 %
20.0 %
26.7 %
33.3 %
40.0 %
44.4 %
50.0 %
% Step Change
11.1 %
8.9 %
6.7 %
6.6 %
6.7 %
5.4 %
5.6 %
0.0 %
DS352PP3
JUL 2001
109
Register Descriptions