7265 Programmer’s Manual 29
Copyright © 2004 TallyGenicom Chapter 2 ANSI
Dot GraphicsDot graphics allows you to print individual dots at an y position on the page and thus to print
pictures as well as text. When you enter dot graphics, the pr inter defaults to a dot density of 72
dpi horizontally and vertically, and a line spacin g of 12 lpi. Exiting from dot graphics returns th e
printer to its prior lpi setting. You can also choose a density of 144 dpih x 72 dpiv. The printer
powers up in low density. The density remains as las t set until it is changed, or until power is
turned off.
Each byte of graphics data defines one column of dots that is six dots high. You can think of the
least significant six bits in the byte as controlling the to pmost six wires of the print head, with the
first bit controlling the top wire and the sixth bit contro lling the sixth wire down. If you wanted to
fire all six wires, then you would send a byte with a d ecimal value of 63. Byte values of 0 through
31 decimal are interpreted as control codes, so you have t o add 64 to any graphics data byte less
than 32 decimal.
You would expect to be able to simply add the value 64 dec imal to every graphics data byte; in
other words, just set the seventh bit. This is risky because s ome variations within the 3000
product family interpret decimal 127, the Delete character, within a graphics sequence. The effect
is to delete everything following the last line term inator. The safest course is:
byte_val < 32 then byte_val = byte_val + 64
WEIGHT WIRE
11
!!
22 !!
43 !!
84 !!!!!
16 5 !!
32 6 !
65 66 68 72 88 40 88 72 68 66 65