Radio Shack TRS-80 Model II Reference Manual page 207

Technical Information
Line Printer
Supervisor Calls described in this section:
FUNCTION
CODE NAME PURPOSE
17
PRINIT Initializes the Line Printer Driver.
18 PRCHAR Sends a character to the Printer.
19
PRUNE Sends a line to the Printer.
95
PRCTRL Controls printer operations.
Table 4.9. Line Printer Supervisor Calls
PRINIT
Printer Initialization (function code 17)
This routine initializes the printer driver only. It does not advance the printer paper,
and it does not check the printer status. It will operate whether or not the printer is
on-line.
Entry Conditions
A=17
B = Page length
C = Printed lines per page
D = Maximum number of characters per line
Register C must always be less than or equal to B.
IfB = C
=1=
0,
TRSDOS
will not do any automatic top ofform. However, it will
translate a form feed code
X'OC
or
X'OB'
into the correct number of carriage returns
or line feeds to get the paper to the top of the next form.
If B= 0, C must also equal 0. Similarly, ifC =
°
then B must also equal 0. In such
acase, form feeds
x'oc
and vertical tabs
X'OB'
are not translated but are sent
directly to the printer.
IfD = 0,
TRSDOS
will not translate tabs
X'09'
as one to eight spaces. It will send the
character directly to the printer. It will continue to update the character count, with
tab
X'09'
counting as a single character.
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