Color/Graphics Monitor Adapter
The Color/Graphics Monitor Adapter is designed to attach a wide
variety
of
TV frequency monitors and TV sets (user-supplied
RF
modulator required for TVs).
It
is capable
of
operating in black and
~
white
or
color, and provides three video interfaces; a composite video
port, a direct drive port, and connection interface for driving a user
supplied
RF
modulator.
In
addition, a light pen interface is provided.
The adapter has two basic modes
of
operation; alphanumeric
(A/N)
and all points addressable graphics (APA). Additional modes are
available within
NN
and
AP
A modes.
In
NN
mode, the display can
be operated in a 40x25 mode for low resolution monitor and TV s or
80x25 mode for high resolution monitors.
In
both modes, characters
are defined in an 8x8 box and are 5x7 with one line
of
descender for
lowercase (both uppercase and lowercase characters are supported in
all modes).
In
black and white mode, the character attributes
of
Reverse
Video, Blinking and Highlighting are available.
In
color mode, there are
16 foreground colors and 8 background colors available per character.
In addition, blinking on a per character basis is available.
The adapter card contains 16KB
of
storage; thus, for a 40x25 screen,
1000 bytes are used to store character information and 1000 bytes are
~
used for attribute/color information. This means that up to 8 pages
of
screens can be stored in the adapter memory. Similarly, in an 80x25
mode, 4 pages
of
display screen may be stored in the adapter. The full
16KB storage on the display adapter
is
directly addressable by the
processor allowing maximum software flexibility in managing the
screen.
In
NN
color modes, it is also possible to select the screen
border color. One
of
16 colors may be selected.
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