Operation Manual
CHR$(27);" = ";CHR$(41 );CHR$(0);CHR$(20);CHR$(65);CHR$(attr1);
CIIR$(attr2);CHR$(col1)
...
CHR$(col11);CHR$(attr1);CHR$(attr2);
CHR$(col1)
...
CHR$(col11);CHR$(attr1);CHR$(attr2);CHR$(coll)
...
CHR$(col11)
If
we
are
replacing
one
character
and
never
use
the
@ symbol,
we
would
give the
start
code as decimal
64.
So
now
we
have this:
CHR$(27);" = ";CHR$(15);CHR$(0);CHR$(20);CHR$(64)
Note: \lotice how the CHR$ following"=" changed in the last two statements.
It
is because the first statement loads three characters, making the formula:
(3
x 13) + 2 =
41
\'l.'hile
the second statement loads only
one
character, making the
formula
(1
x
13)
+ 2 =
15.
Step 6 The two attribute byte codes
Now
we
define the characters to
be
loaded. Each character consists
of
13 bytes - 2 attribute bytes
and
11
bytes
of
print
data.
Attribute byte
1:
You have a choice
of
four values: These select ascender
or
descender
characters (values
0
or
128),
or
graphics characters (values 1
or
2).
0:
The character is
being
printed
with
the lower 8 pins.
128: The character is
being
printed
with
the
upper
8 pins.
Using
one
of
the
other
two
values
(1
or
2)
you can quite easily create
characters which are similar to IBM-Graphic characters
and
which
are
12
dots high.
Two
passes
make
the
printer
print
as if it has a
12-
pin printhead:
1:
Pins 9-12
print
the
same
as
pin
8 (Va
lu
e 1).
2:
The
pattern
of
pins
1-4
(values 128, 64,32
and
16; see
illustration in Step
6:
Designing a Character) will
be
printed
again
on
pins
9-12.
IBM
Modes Advanced Features
4-3