Graphtrax II

We’ll label these top 8 pins as follows:

128 - 0 TOP

64 - o

32 - o

16 - o

8 - O

4 - o

2 - o

l - o BOTTOM

o (Ninth pin not used)

From now on we will refer to the second pin (pin 1 above) as the “bottom” pin when using graphics.

Why not label them 1, 2, 3, . . . 8 etc? Well, the numbers shown are the actual ASCII numbers that fire the respective pins. CHR$ (128) fires the top pin, while CHR$ (1) k-es the bottom one. CHR$ (7) fires the bottom three (4+2+1). Just no way to escape Binary math when dealing with computers, is there?

Add these lines:

20FOR P = 1 TO 5 0

30PRINT CHR$ (l);

40NEXT P

50PRINT

59 PR #0

(Apple)

and RUN.

Sure enough, fifty little dots. CHR$ (1) in line 30 caused the bottom pin to fire. The semicolon suppressed the line feeds. The FOR-NEXT loop fired the bottom pin 50 times.

Change line 30 to:

30 PRINT CHR$ (127);

and RUN.

Figure 5-1

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