Radio Shack TRS-80 MICRO User Manual

External
Program Mode
On
some
special
wheels,
such as
OCR-B
10
and
others,
you
need
to
"externally"
control the
following
(the box of such
wheel
shows
"Require
Special
Programming").
•
Spacing
between printed
character
(Proportional
space
mode
only)
•
Amount
of
ribbon
feed
•
Hammer
impression
level
(For
ordinary
fonts,
these
are controlled
by
the
program
in
ROM.)
Each character or
symbol
requires
a
different
amount
of
the
three
factors
above.
First,
you
must
enter External Program Mode by
sending
control
codes 27,
24
(IB,
18).
Then
send
a two-byte code
for
each character/symbol.
The
first
byte
is
the
ASCII
code,
the
second
byte
contains the data specifying the
printing
format.
Refer
to
the
table
on
Page
19.
For
example, capital
letter
"T"
in
OCR-B font
requires
1/10"
spacing,
normal
ribbon
feed,
and
level
4
of hammer impression.
1/10"
(=
6/60")
is
0110.
Normal ribbon feed
is
1.
Level
4
of
hammer
impression
is
100.
Put
together,
we
get 01101100, which
is
108
is
in
decimal,
6C in
hexadecimal.
By
sending
this data (108 or
6C),
capital
"T"
is
printed
properly
on
OCR-B
10
font.
The code
for
each character/symbol
is
specified
in the
code
chart
provided
with
each
wheel.
To return
to
normal
mode, send code 27,
25 (IB, 19).
When you
turn
the
power
switch
off and
then switch back on again, the
Printer will
be in
the
normal
mode.
Programming example
To
print "Tandy" on
OCR-B
10
print
wheel.
10
LPRINT
CHRS
(27)
CHR$
(24);
'ENTERS
EXTERNAL
PROGRAM
MODE
20 LPRINT
CHRS
(84)
CHRS
(108);
'PRINT
CAPITAL
T
30 LPRINT
CHRS
(97)
CHRS
(107);
'PRINT
LOWERCASE
A
40 LPRINT
CHRS
(110)
CHRS
(107);
'PRINT
LOWERCASE
N
50 LPRINT
CHRS
(100)
CHRS
(108);
'PRINT
LOWERCASE
D
60
LPRINT
CHRS
(121)
CHRS
(107); 'PRINT
LOWERCASE
Y
Note:
That first
codes of each
program line are
ASCII codes
for
each
character.
Of
course
you
can
program
each character
inside quotation
marks
instead
of
sending
code
in
ASCII.
For
example, line
10
can
be
10 LPRINT "T"
CHRS
(108);
-
18-

Radio Shack TRS-80 MICRO Specifications

General

Brand	Radio Shack
Model	TRS-80 MICRO
Category	Printer
Language	English