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Put the printer in data dump mode and then RUN the program.
Remember to press the ON LINE button to make the LX-80 print
the final line. Then compare your printout with the list of hex codes
in order in the middle columns of page A-2 in Appendix A. If any are
skipped or repeated, you will know that your BASIC language
changes some codes before it sends them to the printer.
For example, in the line below, which is the first line of the print-
out of the test program run on a QX-10, you can see that in this case
MBASIC changes hex 09, which is the code for horizontal tabbing, to
several 20s, the code for a space. Therefore, you know that if you use
this system, you must be careful about sending a decimal 9 (hex 09).
The data dumping capability can help you debug a program quick-
ly. Appendix A will help you translate the hex codes to ASCII
equivalents.
Coding Solutions
Once you've determined that a code creates problems for your
printing, either by trial and error or by using the data dumping
capability of the LX-80, you can start overcoming them.
Because each computer system deals with ASCII codes differently,
it is impossible to provide solutions for all potential problems in one
appendix. We can, however, point out generic problems and suggest
ways to handle them.
There are four common approaches. First, you may be able to buy
an alternative printer interface card for your system. This is the best
solution for 7-bit system problems. See your computer dealer for
advice about this.
The second approach is to use commercially available software that
is specifically designed to overcome these coding problems. Consult
your computer dealer or computer publications to see if a program
for your computer system is available.
The third approach consists of avoiding the software that is chang-
ing the codes. On most computers you can send each code directly to
the printer port. This bypasses the BASIC interpreter and avoids the
interface.
F-8
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