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Creating Your Own Characters
121
L
forth between character sets. Knowing that you wouldn't want to
do that, Radix won't even allow it. Standard characters and
download characters cannot be mixed in a line. If you want to use
download characters, the command should appear at the begin-
ning of the line. All subsequent characters (even on following
lines) are printed with the download set until you return to the
standard characters with an (ESC) "$" CHR$(O). (Note that the
(ESC) "$" CHR!$(l) command can be in the middle of a line, and
that entire line will be printed with the download characters. Like-
wise, if you select the standard character set anywhere in a line,
the entire line will be printed with the standard characters. Con-
flicting commands within a line can cause unpredictable results.)
So does that mean that in order to print something meaning-
ful with our special symbols we have to define an entire alphabet?
Fear not. The engineers at Star have made it an easy task to use
mostly standard characters with just a few special characters
thrown in. This command copies all the characters from the
standard character ROM into download RAM:
'c_
(ESC) lr*ll CHR$(@)
Since it will copy all characters into the download area, it will
wipe out any characters that are already there. So it's important to
send this command to the printer before you send any download
characters you want to define. With that in mind, add this line to
the program we used to send the characters to Radix:
25 PRINT #l, CHR$(27) tr*v CHR$(@) ; 'Copy ROM to RAM.
Now try the download printout test program again. Your
results should look like Figure 11-12. You probably noticed that
our printout test includes the characters with ASCII values from
160 to 254, but nothing prints. The (ESC) "*" CHR$(O) command
copies only the standard ASCII characters (those in the range of
33 to 126) to download RAM; it does not copy any block graphics
characters.
To demonstrate how to use these characters, let's use this
character set with a word processing program to print a grocery
ad. Just as you learned in Chapter 3, send the printer control codes
to select download characters (27 36 1) followed by this text:
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