Download Commands - Epson FX-80 User Manual

put there yourself. Characters that haven't been defined print as blank
spaces. So the RAM area is like a big blank chalk board waiting for
you to fill it up. At this point, because you have only defined an
E,
that's all you get from RAM.
Download Commands
Wouldn't it be nice if you could magically transport some of the
ROM characters over to the RAM area so you wouloot have to
switch back and forth or define an entire character set each time you
use the RAM area? Sure it would. There are plenty of applications
where you only need to define a few special characters tO'be used with
the standard alphabet and numbers. That's why the FX-80 provides
the option of copying (sometimes called downloading) the entire
ROM set into the user-defined RAM area.
The download command has the format:
LPRINT CHR$(27)": "CHR$ (n
1 )
CHR$ (n
2 )
CHR$(n
3 ) ;
This command is designed with possible future expansion in mind.
For now, set all three numbers to 0:
1113
LPRINT CHR$(27)":"CHR$(f3)CHR$(f3)CHR$(f3);
Now RUN the program:
SPSON
That's more like it! You get the custom designed E and the normal
characters copied over from the ROM. Notice that the
E
is lower on
the page than the other characters even though the high-order bit of
the attribute byte is on. What gives? Well, in order to save 7-bit users
from total frustration, we designed the character to use the bottom
seven rows (as in Figure 17-4a). Normally, the top seven rows are used
for all but lower-case characters with descenders.
Caution: Be very careful about using the Master Reset Code after
defining your own characters in RAM. This code wipes out
the entire contents of RAM . . . goodbye user-defined char-
acters!
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