Epson FX-80 Operation Manual page 138

LESSON 3 _
In this lesson, how to specify descender data is explained.
Until now, we have been using (139)D as the attribute data. The attribute data
contains not only the descender data which determines whether or not the
character is to be shifted down one dot at the time of printing, but also the
proportional data which determines the size of the print area. (Refer to lesson 4 for
details of the proportional data. Also see the explanation of the attribute on page
3-80.) What follows below is an explanation of the descender data. Shifting the
character down one dot at printing is accomplished by firing the 9th pin of the
printer head. Therefore, a character made up of an 8-dot (vertical) pattern will be
shifted down one dot and printed. The descender data is used when printing such
characters as lowercase "p" and "g" of the internal character set.
Descender data not Descender data
specified specified
The figures above show the box pattern defined in Lesson 1. @ is the result of
printing without descender (9th dot wire not used) and @ is the result of printing
with descender (9th dot wire used).
When specifying the descender data in the attribute, the following points should be
kept in mind.
The descender is specified by the MSB of the attribute. When the MSB of the
attribute is "0" , the descender is specified and when the MSB of the attribute data is
"1", the descender is not specified.
The attribute data (139)D that we have been using so far does not specify the
descender. If we look at the binary equivalent of (139)D, <1000 1011>2, we can see
that the MSB of this data is "1". The lower 7 bits of this data are used to specify the
proportional data. (See Lesson 4.)
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