User-defined Characters
As you can see, both sets of characters (the original ROM
characters that the printer normally uses and the
user-defined
character set) remain in the printer available for your use. The
command to switch between the two sets is used in line
180
and
200.
It is:
ESC
%
n
If
n
is equal to
0,
the normal ROM character set is selected. If
R
is
equal to
1,
the userdefined character set is selected. You can also
select one of the two character sets with DIP switch
2-1.
If you
select the
user-defined
character set before you have defined any
characters, the command is ignored and the ROM characters remain
in use.
You may switch between
character sets at any time, even in the
middle of a line. To try this, place semicolons at the end of lines
170
and
190
in the preceding program.
Copying ROM characters to RAM
After nmning the previous sample program, if you select the
user-
defined character set and try to print other characters, only the
heart will print. Since no other characters are in the printer’s
user-
defined RAM area, other characters print as spaces.
In many cases, you will want to redefine only a few of the
characters to suit your needs; the rest of the alphabet will work fine
as it is. As you have seen, it is possible to switch back and forth at
will between the normal character set and
user-defined
character set.
It is, however, rather inconvenient.
Therefore, your printer has a command that allows you to copy all of
the standard characters from ROM to the user-defined character set.
The command format is:
ESC:O
n
0
Software and Graphics
4-27
