4/ Ptc-64; Control Sequences - Radio Shack TRS-80 Operation Manual

4/
PTC-64
Control Sequences
The PTC-64
offers several
Control Sequences
that
permit
a variety
of
printing control
operations.
These
Control
Sequences can be
sent
in
the
BASIC
immediate
mode
or
included
in
any program.
The
general format for the Control
Codes
is:
L
PR
I
NT CHR$<«/)5 CHR$(«2)5
where nl and nl
are the
ASCII
values for a particular
Control Sequence, nl
is
27,
which
informs the Printer Controller
that
a
special
sequence
follows.
Note:
If
a
semicolon
is
not included
at
the
end
of
a Control Sequence,
the printer will
execute a carriage return.
Depending on your
purpose,
this
may
or
may
not
be
desirable.
The
Control Sequences can be
turned
OFF
by
pressing the
COPY
and
PAUSE
keys
together (or
by
using the
sequence 27 36 described below).
While
the
PTC-64
Control
Sequences
are
OFF,
the buffer
will
pass
all
sequences through to the printer.
To
re-enable them, press
the
CLEAR
and
COPY
keys together, turn
power OFF,
or
perform
the Self-Test. Just
remember
that
all
information
in
the buffer
is
erased
when
you
turn
the
power
OFF
or execute
the self-test.
Also,
if
you perform
the Self-Test, a
message
will
be
printed.
The
following
is
a
list
of
all
permissible Control
Sequences and
a brief description
of
each.
Be
aware
that
these are exclusively
PTC-64
Control Codes.
Your
printer
may
recognize
many
others.
BEEPER
Causes
the Printer Controller
to
sound beeper
for 1/2 second.
27
42
(Dec.)
IB
2A
(Hex.)
For example, L
PR
I
NT
CHR*(27>5 CHR$
(
42
) i
will
sound the beeper.
CLEAR
This sequence has
the
same
functions as the
CLEAR
key
(see pg.
3).
27 33
(Dec.)
IB
21
(Hex.)
For example,
when
active,
L
PR
I
NT
CHR$<27)5 CHR$
(
33
)i
will stop
any
printing.
When
inactive,
LPRINT
C H R $
(
2 7
>
i
C H R $
(
3 3
) i
will clear the
buffer
and
reset the
start
point for multiple copies.