SB-10 USER'S MANUAL

Table f-2. Calculating the width of your graphic image.
IF THE NUMBER OF
COLUMNS RANGES FROM: THEN nl IS: AND n2 IS:
1to255 X 0
256 to 511 x -256 1
512 to 767 x-512 2
768 to 1023 x -768 3
1024 to 1279 x-1024 4
1280 to 1440 x-1280 5
128
64
32
16
8
4
2
1
Figure F-5. Pin values for 8-bit graphics.
To fire, say, the second pin from the top, you’ll send the BASIC
code CHR$(64). You can fire several pins at once by adding their
values and sending the sum total in a single BASIC CHR$ code. Thus:
To fire the
then send
1st 3rd and 4th -> the BASIC -> CHR$(176)
pins, add their
CHR$ code:
values (128 + 32 + 16)
Here’s a short program to show you how you can implement 8-bit
graphics to make a simple zigzag image (Figure F-6).
NEW
10 'PRINT GRAPHIC PATTERN
20 WIDTH "LPT1:".255
30 LPRINT CHR$(27) CHR$(89) CHR$(94) CHR$(l);
40 FOR I=1 TO 25
50 FOR J=O TO 6
60 L-PRINT CHR$(2-J);
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