Epson LX-90 User Manual - Apple IIc 8699 PIC for LX-90 - Page 108

Graphics, Data Dump Mode, PRINT CHR$9;CHR$1

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Or you can reassign the special use by putting the following line near the beginning of your program: 10 PRINT CHR$(9);CHR$(1) Until you reassign the CHR$(9) code by one of these methods, you cannot use it for horizontal tabbing. Graphics There are two common sources of problems with graphics programs in BASIC: 1. Unwanted codes for carriage returns and line feeds may be inserted by BASIC if lines are over 80 columns long or if semicolons are not used at the end of program lines between the graphics command and its data. See Chapter 7 for the proper format for the "Z" command statement and for sample programs that show the proper use of semicolons. 2. If the printer stops during a graphics program, it may not have received enough data. The printer expects a certain number of pin patterns, determined by nl and n2 in the graphics command. It will wait patiently until the quota is full. Note that 9-pin graphics mode requires two bytes for each column of graphics. Data Dump Mode The LX-90 has a special feature that makes it easy for experienced printer users to find the causes of problems. Called the data dump mode, it gives a printout of exactly what codes reach the printer. Enter this mode by turning on the power switch on the right side of the printer while holding down the FF and LF buttons at the same time. The printer responds by printing the words "Data Dump Mode." Then, when you run a program, either an applications program or one you have written in any programming language, the LX-90 prints one or more lines. Each line has three parts: the line number (four digits), the hexadecimal codes (up to 16 numbers), and the guide section (16 characters at the end of each line except the last). The hexadecimal numbers are the codes received by the printer, and the guide section helps you find a certain place in the list of codes. Each character in the guide section corresponds to one of the codes. If the E-7

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Or you can reassign the special use by putting
the
following line near
the
beginning of your program:
10 PRINT CHR$(9);CHR$(1)
Until you reassign the CHR$(9) code by
one
of these methods, you
cannot use it for horizontal tabbing.
Graphics
There are two common sources of problems with graphics pro-
grams in BASIC:
1.
Unwanted codes for carriage returns and line feeds may be inserted
by BASIC if lines are over 80 columns long or if semicolons are not
used at the end of program lines between the graphics command
and its data. See Chapter 7 for the proper format for the “Z” com-
mand statement and for sample programs that
show
the proper use
of semicolons.
2. If the printer stops during a graphics program, it may not have
received enough data. The printer expects a certain number of pin
patterns, determined by
nl
and
n2
in
the
graphics command. It
will wait patiently until the quota is full. Note that 9-pin graphics
mode requires two bytes for each column of graphics.
Data Dump Mode
The LX-90 has a special feature that makes it easy for experienced
printer users to find the causes of problems. Called the data dump
mode, it gives a printout of exactly
what
codes reach
the
printer.
Enter this mode by turning
on
the power switch on the right side of
the printer while holding down the FF and LF buttons at the same
time. The printer responds by printing the words “Data Dump
Mode.” Then, when you run a program, either an applications pro-
gram or one you
have
written in any programming language,
the
LX-90 prints one or more lines. Each line has three parts:
the
line
number (four digits), the hexadecimal codes (up to
16
numbers), and
the guide section
(16
characters at the end of each line except the last).
The hexadecimal numbers are the codes received by the printer, and
the guide section helps you find a certain place in
the
list of codes. Each
character in the guide section corresponds to one of the codes. If the
E-7