Epson FX-80 Operation Manual page 131

<The relationship between character data and dot wires>
The dot wires fired in printing are represented as a decimal character data where
the dot wires correspond to the bit positions as shown in the below figure.
2
7
(128)
2
6
(64)
2
5
•
(32)
2 4
(16)
2'+2
2
+2
5
=2+4+32=38
0
2
3
(8)
2
2
•
(4)
2
1
•
(2)
2°
(1 )
<How to obtain attribute "a">
Attribute "a" is obtained in the following manner.
As shown in the figure below, attribute "a" consists of descender data and
proportional data. The descender data determines whether the 9th dot will be used
and the character shifted down one dot, and the proportional data determines the
starting and ending positions of the print area.
{
9th dot-wire used 0
• Descender data -
1
9th dot-wire not used
L,
g }
~:~n~i~~sition
]
, ) Proportional data
o
Ending
, print position
·n
In the above figure, the high-order 3 bits of the 7-bit proportional data represent
the starting print position and the remaining 4 bits indicate the ending print
position. In this example, attribute "a" is:
(10001011)2
=
<8B>H
=
(139)0
I