HP Vectra Technical Reference Manual page 37

In either of the text modes (80
x
25 or 40
x
25) nlemory is organized as sequential pages. Each
page contains character cells that are made up of an 8 bit character code and an 8 bit attribute
(see Figure 3.1).
Text Display Memory Organization
~
Character Cell Organization Color Values
Byte 0
I R G B Color
8 Bit Char Code
I I
0 0 0 0 Black
0 0 0
1
Blue
0 0 1 0 Green
Blink bit
0 0 1 1 Cyan
1
=
Blinking on
0 1 0 0
Red
o
=
Blinking off
0
1 0 1
Magenta
0 1 1 0 Brown
Background color
0 1 1
1 Light Grey
1 0 0 0 Dark Grey
Intensity bit
1 0 0 1 Light Blue
1
=
High
1 0 1 0 Light Green
o =
Low
1 0 1 1 Light Cyan
1 1 0
0 Light Red
Foreground color
1
1
0
1
Light Magenta
1 1 1 0 Yellow
1 1 1
1 White
~
80
X
25 Text Memory Page
CeliO
Cell 1
Cell 79
Page 0
(OB800:0H)
Page 1
(OB800:0FAOH)
Byte 0 Byte 1
I
I
•••
I
•
•
•
I
I
•••
I
Figure 3.1
Row 0
Row 1
Row 24
Row 0
Row 1
Graphics modes can be of two types: medium resolution (320
X
200 or 320
X
400) and high
resolution (640
X
200 or 640
X
400). In the medium resolution mode each pixel corresponds to
two bits of memory so four colors can be displayed. In the high resolution modes each pixel
corresponds to one bit of memory and only one color can be displayed (the background color is
always black). See Figures 3.2 and 3.3 for more details.
28 Video