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102
Radix User's Manual
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tionally, and the bottom is printed unidirectionally. You will have
to look hard because there isn't much difference.
Let's analyze the program. Line 20 sets the line spacing to
7/72
of an inch so that the characters that we print will touch top to
bottom. Lines 30-50 print
10
vertical line characters. Then line
70
sets one-direction printing and the vertical lines are printed again.
Finally line
110
sends a form feed to advance the paper to the top
of a new page, and then uses the master reset to restore Radix to
the power-on condition.
The seven bit dilemma
Certain computers (most notably the Apple II) don't have the
capability to send eight bits on their parallel interface. They can
only send seven bits. This would make it impossible for these
computers to use Radix's block graphics characters and special
symbols if Star's engineers hadn't thought of a solution. (All of
these characters have ASCII codes greater than 127 which means
that the eighth bit must be on to use them.) The solution lies in the
three control codes given in the following table.
.
1 Function
Table lo-4
Eighth bit control commands
I Control code
I
\
Turn the eighth bit ON
Turn the eighth bit OFF
Accept the ei hth bit
"as is" from t a e commder
(ESC) I')"
(ESC) 'I="
(ESC) "It"
-.
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Block gmphics chamcters and special symbols
Besides the upper and lower case letters and symbols that we
are by now familiar with, Radix has a whole different set of char-
acters that are for special uses. These characters include block
graphics characters for drawing forms and graphs, and special
symbols for mathematical, engineering and professional uses.
The following program will print out all of the graphics characters
available.
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_.
10 'Prints all block graphic
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characters.
20 WIDTH "LPT1:",255
30 FOR J = 160 TO 255 STEP 8
40 FOR I = J TO J + 7
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