83
character sets, and the NLQ characters.
But there is another area of memory in this printer reserved
for user-defzked characters. These are characters that you can
design and download into the printer. When download
characters are defined they are stored in RAM (random access
memory), which allows you to define or modify them at any
time.
Each of these characters, whether it is from the standard
character ROM or in download RAM, is constructed on a grid
which is six “boxes” by nine “boxes” high. In addition, a dot can
straddle any of the vertical lines. As an example, take a look at
the enlarged “9” superimposed on the grid in Figure 6-3. As you
can see, some dots are inside the boxes, and some are centered
on the vertical lines. This, in effect, makes the character grid 11
dots wide by 9 dots high. To see how the rest of the characters
in the standard character ROM are constructed, take a look at
Appendix C.
L ___ _ . -..
Figure 6-3. Dots can be inside boxes or straddle the vertical lines
of the grid.
DEFINING YOUR OWN CHARACTERS
You’ve seen how these characters are designed by using a
grid to layout the dots. Now you can define characters exactly
the same way. Make up some grids (photocopy Figure 6-4 if you
wish) and get ready to be creative! (Just in case you are not feel-
ing creative, and to make our explanations a little clearer, we’ll
be using a picture of a chemist’s flask as an example of a draft