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- ON SCREEN DISPLAY CONTROLLER (OSD)
OSD CONTROLLER (Cont’d)
8.5.6.3 Foreground Palettes
The foreground palettes (Basic and Extended)
both use the same principle:
– The basic foreground palette is stored in OS-
DRAM (segment 22h) starting from 10h to 2Fh
(see Figure 59).
– The extended foreground palette is stored in OS-
DRAM (segment 22h) starting from 50h to 6Fh
(see Figure 59).
A 16-bit word is used to define each color in the
palette, located at even addresses between 10h
and 2Eh (even value) for the basic foreground pal-
ette, and between 50h and 6Eh (even value) for
the extended foreground one.
Figure 62. Basic Foreground Palette Mapping
Bits 15 = Free for the user
Bits 14:12 = U[2:0]
Underline mode control bits.
These bits configure the underline mode for the
dot line 12 (lines 23 and 24 if using the 18x26 ma-
trix) and line 13 (lines 25 and 26 if using the 18x26
matrix).
See Table 24.
Bits 11:9 = FT[2:0]
Foreground Translucency
These bits configure the foreground translucency
level applied to the color (refer to Section 8.5.3.11
for more details).
FT[2:0] = 7 means that this color will be fully
opaque (no video mixed in it on the display)
FT[2:0] = 0 means that this color will be fully trans-
parent (the video is displayed instead of this color)
Bits 8:6 = FR[2:0]
Foreground Red color
These bits configure the foreground red intensity
for the color.
FR[2:0] = 0 means that no red is used to define the
color.
FR[2:0] = 7 means that the maximum red intensity
is used in the color.
Bits 5:3 = FG[2:0]
Foreground Green color
These bits configure the foreground green intensi-
ty for the color.
FG[2:0] = 0 means that no green is used to define
the color.
FG[2:0] = 7 means that the maximum green inten-
sity is used in the color.
Bits 2:0 = FB[2:0]
Foreground Blue color
These bits configure the foreground blue intensity
for the color.
FB[2:0] = 0 means that no blue is used to define
the color.
FB[2:0] = 7 means that the maximum blue intensi-
ty is used in the color.
15
8
7
0
U2
U1
U0
FT2
FT1
FT0
FR2
FR1
FR0
FG2
FG1
FG0
FB2
FB1
FB0
10h
2Fh
U[2:0] FT[2:0] FR2
FR[1:0] FG[2:0] FB[2:0]
Color
0
Color
1
12h
U[2:0] FT[2:0] FR2
FR[1:0] FG[2:0] FB[2:0]
14h
Color
15
U[2:0] FT[2:0] FR2
FR[1:0] FG[2:0] FB[2:0]