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Radio Shack Quick Printer II Operation Manual

Radio Shack Quick Printer II
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Computer
Graphics
Operation
Manual
----------TRS-BO
®
----------
5/
programming
the
Graphics
Board
The
Graphics
Board
provides
64~
X
24~
byte
addressable
pixels
on
a
TRS-8~
Model
III.
The
Graphics
Board
contains
32K
of
screen
RAM
to
store
video
data
consisting
of
four
64K
RAMs
which
are
double
accessed
for
8
bytes
of
data.
Regular
alphanumeric
data
is
stored
in
the
static
RAM
on
the
Video
Board.
The
Graphics
Board
uses
separate
hardware
to
generate
a
64~
X
24~
display,
so
only
one
screen
may
be
displayed
at
a
time.
If
the
video
is
switched
from
Text
to
Graphics
Screen
very
rapidly,
the
Video
display
may
lose
horizontal/vertical
synchronization.
I/O
port
mapping
is
used
to
read
and
write
data
to
the
board.
The
Board
is
addressable
at
8~-83
Hex.
There
are
four
internal
registers
which
can
be
written
to
or
read
on
the
board.
They
are
as
follows:
1.
X-Position
2.
Y-Position
3.
Data
4.
Options
X-address
(~
to
127)
for
data
write
only.
(~
to
79
for
display.)
Y-address
(~
to
255)
for
data
write
only.
(~
to
238
for
display.)
Graphics
data
in
"byte"
form.
Each
byte
turns
on
or
off
8
consecutive
horizontal
dots.
8
flags
which
turn
on
or
off
the
user
programmable
options
(Write
only).
The
I/O
port
mapping
of
the
board
is:
x~
-
X-Register
Write.
(8~)
xl
-
Y-Register
write.
(81)
x2
-
Video
data
read
or
write.
(82)
x3
-
Options
write.
(83)
where
x
denotes
the
upper
nibble
of
the
I/O
boundary
as
set
by-the
DIP
switches.
They
are
set
by
the
factory
at
8~H.
The
Graphics
Board
uses
X-Y
addressing
to
locate
the
start
of
a
Graphics
data
byte.
The
upper-left
of
the
screen
is
(~,~)
while
the
lower-right
is
(~79,239).
If
the
bit
is
a
1,
the
dot
will
be
ON.
For
example,
if
you
wanted
to
turn
----------lIadlelllaell----------
-114-

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Radio Shack Quick Printer II Specifications

General IconGeneral
BrandRadio Shack
ModelQuick Printer II
CategoryDesktop
LanguageEnglish

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