sed1355 ETC-unknow, sed1355 Datasheet - Page 178

• Manufacturer Part Number: sed1355
• Description: Sed1355 Embedded Ramdac Lcd/crt Controller
• Manufacturer: ETC-unknow

Page 22
SED1355
X23A-G-003-05
4 bpp gray shade
The 4 bpp gray shade mode uses the first 16 LUT elements. The remaining indices of the LUT are
unused.
8 bpp gray shade
When 8 bpp gray shade mode is selected the gray shade intensity is determined by the green LUT
value. The green portion of the LUT has 16 possible intensities. There is no color advantage to
selecting 8 bpp mode over 4 bpp mode; however, hardware rotate can be only used in 8 and 16 bpp
modes.
15 bpp gray shade
The Look-Up Table is bypassed at this color depth, hence programming the LUT is not necessary.
As with 8 bpp there are limitations to the colors which can be displayed. In this mode the four most
significant bits of green are used to set the absolute intensity of the image. Four bits of green resolves
to 16 colors. Now however, each pixel requires two bytes.
16 bpp gray
The Look-Up Table is bypassed at this color depth, hence programming the LUT is not necessary.
As with 8 bpp there are limitations to the colors which can be displayed. In this mode the four most
significant bits of green are used to set the absolute intensity of the image. Four bits of green resolves
to 16 colors. Now however, each pixel requires two bytes.
Table 4-8: Suggested LUT Values for 4 Bpp Gray Shade
Index
0A
0B
0C
0D
0E
0F
FF
00
01
02
03
04
05
06
07
08
09
10
...
Required to match CRT to panel
Red
A0
B0
C0
D0
E0
00
10
20
30
40
50
60
70
80
90
F0
00
00
00
Unused entries
Green
C0
D0
A0
B0
E0
F0
00
10
20
30
40
50
60
70
80
90
00
00
00
Blue
A0
B0
C0
D0
F0
00
10
20
30
40
50
60
70
80
90
00
00
00
E
Epson Research and Development
Programming Notes and Examples
Vancouver Design Center
Issue Date: 99/04/27