Proportional Print Information; Use Of Pins Chosen By Attribute Byte - Epson FX-80 User Manual

9
0
Not used Attribute byte
8
0 • • •
•
• •
OFF
7
0
••••
•
LQL[I I I I I
6
0
••
• •
••
12864 32 16 8 4 2 1
5
0
••••••
If attribute byte it less than 128,
4
0
••••••
3
0
••
•••
•
bottom eight pins are used
2
0
••
•
•••
0
••••
•
9
0
•
•
•
• • •
Attribute byte
8
0
••••
•
ON
7
0
••
· · e·
[ 1
I I I I I I
I
6
0
•••••
•
12864 32 16 8 4 2 1
5
0
•••••
•
4
0
••
· e· ·
If attribute byte is 128 or greater,
3
0
••
· · e·
top eight pins are used
2
0
••••
•
0
Not used
Figure 17·4. Use of pins chosen by attribute byte.
Proportional print information
The attribute byte also contains information used to print a charac-
ter in Proportional Mode. It tells the printer in which columns to start
and stop printing for each character. If we label the 11 columns deter-
mined by the data numbers as columns 0 to 10, then in Proportional
Mode the minimum and maximum starting and stopping columns will
be 0 and 11. Why 11 instead of 10? Column 11 is the maximum value
because Proportional characters are always Emphasized; this makes
each character wider by one "intermediate dot column" (see Chapter 4
on the Emphasized Mode). So when defining your own characters for
proportional printing, always reserve one extra column.
Let's create a sample attribute byte together. Suppose you want a
character to start in column 1 and end in column 10. How do you put
this information into the attribute byte? Easy, just follow along. The
starting column number (1) is converted to a 3-bit binary number
(001) and stored in bits 4, 5, and 6 of the attribute byte. The ending
column number (10) is converted to a 4-bit binary number (1010) and
stored in bits 0 to 3. The conversions are shown in Figure 17-5.
200