Printing Low-Order Control Codes - Epson FX-80 User Manual

The lower-order control codes can also be defined, but not all of
them can be printed with ease. (ESC) "11" makes them printable, and
(ESC) "10" returns them to normal.
Just as the higher control codes hide the italic international charac-
ters, the lower control codes hide (you guessed it!) the roman interna-
tional characters. But let's see how the (ESC) "11" and (ESC) "10"
codes work with user-defined characters. Change:
13~
LPRINT CHR$(27)"&"
CHR$(~)CHR$(l)CHR$(J);
14~
FOR Y=l TO 3: LPRINT CHR$(139);
165 LPRINT CHR$(27)"Il"
18~
LPRINT CHR$(1)CHR$(2)CHR$(3)
And add:
11~~
DATA
~,121,~,73,~,73,~,73,~,79,~:
I
My S
111~ DATA ~,127,~,65,~,65,~,65,~,127,~:
I
My Oh
sow
The program now contains six DATA lines, but
it
uses only the first
three. The three characters are stored in ASCII codes 1, 2, and 3 in
RAM; they are printed from line 180.
Printing low-order control codes
Not all of the low-order (0 to 31) control codes can be changed to
print as normal characters-nor would you want them to. Imagine, if
you changed code 27 to print as a normal character . . . no more
ESCape codes! You would have a hard time getting anything done.
Codes that currently activate special modes or actions by the
printer cannot be printed as normal characters. These include 7 to 15,
17 to 20, 24, and 27. However,
it
is possible to print the characters
stored in these locations with the (ESC) "R" command.
Here's how it works. Suppose you choose to define the ASCII code
8 (normally a backspace). The (ESC)" &" command will work fine,
but printing CHR$(8) still produces a backspace, even after an (ESC)
"11". (ESC) "R" to the rescue. (ESC) "R" lets you print the character
stored in location 8 with another ASCII code. The (ESC) "R" sort of
magically transports the character to an easily printable location. To
find out what is stored where, use Table 17-1.
207