Epson FX-80 Specifications download pdf (Page 220)

Attribute byte

The attribute byte is the first of the 12 data numbers required to

define any character. At print time it controls two aspects of the way

the character is printed. First, it determines which 8 pins of the print

head are used to print the character. For most characters, the top 8

pins are used, but for lowercase characters with descenders (like g and

p), the bottom 8 pins can be used.

So how does the attribute byte determine which 8 pins are used? At

print time, the printer checks the attribute byte before each character

is printed. If the high-order bit is on, the top 8 pins of the print head

are used; if the high-order bit is off, the bottom 8 are used. To put it

another way, if the attribute byte for a given character is 128 or

greater, the top 8 pins are used; if it is 127 or less, the bottom 8 are

used. Figure 15-4 demonstrates these choices.

ATTRIBUTE BYTE

If attribute byte is less than 128,

bottom eight pins are used

ATTRIBUTE BYTE

If attribute byte is 128 or greater,

top eight pins are used

Figure 15-4. Pins chosen by attribute byte

Proportional print

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 you label the 11 columns deter-

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1 2 ... 215 216 217 218 219 220 221 222 223 224 225 ... 267 268

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Epson FX-80 Specifications Page 220