If
you
are using a commercial software
drawing
or
graphics
pro-
gram
such,
don't
worry
about pin
numbers
with
the MPS 1200;
just
set the
DIP
switches accordingly, and select
"Commodore"
or
"Epson"
from the
printer
options listed in the
program.
The
MPS
1200 prints
dot
graphics in lines,
just
as
it does predefmed
characters.
The
print
head moves across the paper striking the
appropriate pins against the
ribbon
forming a
column
of
dots
on
each line. Tall graphics figures are printed
by
adjusting the line
spacing and printing several lines until the figure
is
complete.
However,
with
dot
graphics the line length and
dot
spacing are
not
fixed
as
they are
with
predefined characters.
To
use
dot
graphics,
you
must
tell the
MPS
1200 three things for each line:
(1)
which
pins to
print
in each column;
(2)
how
closely to space the columns,
called the graphic density; and
(3)
how
many
columns there will be
in the line.
Graphics
Commands
The
graphics
commands
perform
three functions: they tell the
MPS
1200 to interpret the ASCII codes that follow
as
print head pin
number
data instead
of
characters, they set the graphics density,
and they set the
number
of
columns per line,
which
tells the MPS
1200
how
many
pieces
of
data
to
expect. First, let's see
how
the
MPS
1200 prints graphics.
Pin
Numbers
To
tell the
MPS
1200
which
pins to
print
in each column, you need
a
way
to identify the pins in the
print
head.
The
MPS 1200 assigns
each pin a
number
as
shown
in Figure 6.1. Skipping the unused
bottom
pin, they are
numbered
as
powers
of2:
z<
,
21,
22
...
27,
or
in everyday numbers, 1,2,4,8,16,32,64, and 128.
Once
you've
told
the
MPS
1200
you
are using
dot
graphics
with
one
of
the graphics
commands,
you
tell it
which
pins to
print
by
sending the ASCII
code that corresponds to the pin
number
- one code for each
column.
6-3
To Next Page
Loading...
