AMT Datasouth 41AY89AR777 - Manual (Page 159)

APPENDIX H - CONTINUED
Hie dot pattern for each character must be defined in terms of an 8 x 11 dot
matrix. That is, each character can be a maximum of 8 dots tall (See Figure H. 1).
Thirteen bytes are used to define a character. The first two bytes are attribute
bytes. Attribute byte one, represented by the variable “al”, specifies height and
width characteristics of the character. The printer ignores all but the MSB of
the attribute byte. The MSB provides descender data. If the MSB is 1, the
user-defined character will be shifted down by one dot as shown in Figure H. 1.
q
P2 f| fy f| fg fio'll
Figure H.1 Proprinter MSB Equal to 1
If the MSB is 0, the character occupies the top eight dot positions of the matrix as
shown in Figure H.2.
Figure H.2 Proprinter MSB Equal to 0
Attribute byte two, represented by the variable “a2”, specifies proportion spacing
information. Bits 1-4 specify the length of each character (number of columns to
be printed). Bites 5-7 specify the number of blank columns to the left of the
downloaded character. Up to 7 columns can be blank.
H-10