10.
Preset
Upon RESET. The same color scheme as the IBM PC is preset.
Using three bits apiece for R, G, and B,
512
colors are possible. Of those
256
colors,
16
colors may be saved in the
color palette. Bits I, R, G, and B have meanings in IBM PC mode, however, generally the color palette selection
signals do not have meaning.
IRGB R2 R1 RO G2
G1
GO
B2 B1 BO
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Black
Blue
Green
Cyan
Red
Magenta
Brown
White
Gray
Light Blue
Light Green
Light Cyan
Light Red
Light Magenta
Yellow
White (High Intensity)
000000000
000000100
000100000
000100100
011000000
100000100
10001
1000
100100100
001001001
000000110
000110000
000110110
101000000
110000110
110110000
111111111
3DFH (Display Page REGISTER)
This is a
3
bit write-only register. It can’t be read and its address is hex “3DFH” of the four least significant bits of
the I/O address with a
“0”
*IOSEL signal.
When the Page Mode is enabled, this register selects a page from four
16KB
display pages in a
64K
bytes space.
The Page Mode is not supported on the static RAM system configuration due to pin number limit, but it becomes
available for use adding by external circuits.
Other registers function are
as
same as
6845
registers.
F-2
1
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