Z90251 Datasheet, PDF (53/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
45
Table 24 Color Palette Selection Bits
Color Index, Bit [10:8]
000
001
010
011
100
101
110
111
Function
Selects background/foreground color in row attribute
Selects color palette 0 in the color look-up table
Selects color palette 1 in the color look-up table
Selects color palette 2 in the color look-up table
Selects color palette 3 in the color look-up table
Selects color palette 4 in the color look-up table
Selects color palette 5 in the color look-up table
Selects color palette 6 in the color look-up table
There are eight different foreground/background palettes, including the 000h case
that reads the color(s) from the ROW_ATTR register mapped into video RAM.
Color Table and Color Index Register
Table 25 lists the bits in the Color Index Register.
Table 25 Color Index Register 09h: Bank C (CLR_IDX)
Bit
7
6
5
4
3
2
1
0
R/W
R/W R/W R/W R/W R/W R/W R/W R/W
Reset
1
1
1
1
0
0
0
0
Note: R = Read W = Write X = Indeterminate
Bit/
Field
Bit
Position R/W Value Description
Reserved
7, 6, 5, 4 R
W
Return 1
No Effect
Color Index 3, 2, 1, 0 R/W
Data
Bit 3 defines MSb of the character pointer data bit
and bit [2:0] for character color data bits
When the Color Index has a value other than 000h, the value indicates the
number of the color palette that contains the RGB foreground and background
colors to be displayed. In the Color Palette register descriptions below, the
following notation is used:
PS001301-0800