Graphics Mode - Zenith Z-100 Reference Manual

Table 7.3 shows the attribute byte breakdown. As before, bits 7 and 3 determine
blink and intensity, respectively, of the foreground character.
Table 7.3. Color Attribute Byte Logic
COLOR
Black
Blue
Green
Cyan
Red
Magenta
Brown
Light gray
Intensified brown is yellow
Intensified light gray is white
Intensified black is dark gray
Using 25 x 80 format the same rules apply. But, since there are twice as many
characters per row at this resolution, 4000 bytes of video memory are required
to store one screen. This means only four screens may be stored at one ti

Graphics Mode

In graphics mode, two degrees of resolution are available: 320 x 200 and 640
x 200.
640 x 200 resolution is only obtainable as a monochrome display, since the
full 16K of video memory is needed to define the ON or OFF states of a screenful
of picture elements (pixels). If a color other than white is desired for the ON
state of a given pixel, one of the 16 border colors may be selected. This is done
by sending a value from 00H to OFH (0 to 15 decimal) to the color select register
at 3D9H after selecting 640 x 200 resolution.
In 320 x 200 resolution each pixel may be one of four colors. This color may
be one of the sixteen background colors or one of three other colors software
selected from the red/green/brown palette or the cyan/magenta/white palette.
Video Graphics Programming
BACKGROUND BITS
6 5 4
0 0 0
0 0 I
0 I 0
0 I I
I 0 0
I 0 I
I I 0
I I I
Page 7.11
FOREGROUND BITS
2 I 0
0 0 0
0 0 I
0 I 0
0 I I
I 0 0
I 0 I
I I 0
I I I
me.