Attribute Byte Conversions - Epson FX-80 User Manual

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1 • Top 8 pins
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[@;:;-,:::::"~~I
11 1 0 1 0 11 11 1 0 11 1 0 1 Attribute byte
12864 32 16 8 4 2 1
1
1
1
1
128
+
16
+
8
+
2 = 154 decimal value
Figure 17·5. Attribute byte conversions.
The full 8-bit attribute byte, then, is composed of three parts:
1) Bit 7 determines which pins are used to print the character.
2) Bits 4, 5, and 6 determine the starting column number.
3) Bits 0, 1,2, and 3 determine the ending column number.
So the attribute byte constructed in Figure 17-5 (CHR$(154)) would
use the top eight pins, start printing in column 1, and end in column
10.
Note that the proportional print information is used only when the
character is printed in Proportional Mode. Otherwise the full range of
columns 0 to 11 is used. Also note that if 7-bit users set the high-order
bit (with (ESC)")") before the (ESC)"&" sequence, it stays on for
the attribute and character data bytes.
One final note. Even if you choose not to print the columns from 0
through 11, you must send the printer 11 data numbers plus the at-
tribute byte. The printer expects 12 data numbers for each character,
no matter what!
So much for the example. In the current program, we'll set the at-
tribute byte to 139. This value starts at column 0, ends at column 11,
and uses the top 8 pins of the print head. Seven-bit computers can use
139 or 11. Either way, the printer will use the bottom 8 pins for 7-bit
systems. Add:
14~
LPRINT CHR$(139);
201