Commodore 128 Programmer's Reference Manual page 245

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THE POWER BEHIND COMMODORE 128 GRAPHICS 235
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Figure 8-19. Bit Patterns of the "At" Sign (@) Character as They Appear in
Character ROM
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Figure 8-20. Bit Patterns of the "At" Sign (@) Character as They Are Grouped
in Pairs in Multi-Color Character Mode
The bits are grouped in pairs, since the horizontal resolution is only half as wide in
multi-color mode. The bit pair determines the color assignments for the pixels within the
character on the screen. The following section describes how the colors are assigned in
multi-color character mode.
COLOR DATA
The color of the pixels in a multi-color character originate from four sources, depending
on the bit pairs. Since the bit pairs have four color possibilities, two bits are needed to
represent four values: 00, 01, 10 and Hi In Figure 8-21, the value of the four bit pair
combinations determines the color assignments for the pixels in a multi-color character.
BIT PAIR
00
01
10
11
COLOR REGISTER
Background #0 color (screen color)
Background #1 color
Background #2 color
Color specified by the
lower 3 bits in color memory
LOCATION
53281 ($D021)
53282 ($D022)
53283 ($D023)
color RAM
Figure 8-21. Truth Table for Color Data
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