Poke Subroutine; Designing Your Own Graphics - Epson Printer Interface Cartridge for the Apple IIc Operation Manual

POKE Subroutine

Because the Apple IIc has special uses for certain low-numbered
codes, such 4 and 9, you should
as
graphics program that uses numbers below 20 decimal.
10000 IF PEEK (49305) < > 80 then 10000
10010 POKE
10020 RETURN
With this subroutine in your program, two commands will send any
number to the printer: the first makes the number equal to N (for
example, N = 222), and the second is GOSUB
then uses the POKE in line
You can see how this subroutine works in the next program.
If you use this subroutine and also turn DIP switch 2-2 on, you can
send numbers between
lem Codes" in Appendix E for more information.

Designing Your Own Graphics

This section takes you through the development of a graphics pro-
gram. The example is not especially complicated, but it does include
the same steps you would use for a more complex figure so that you
have the basis for designing graphics on your LX-90.
You should plan your
beginning to place the dots, you must decide which graphics density
you want. Figure 7-3 shows the differences between the three most-
used graphics modes so that you can choose the one you want.
Single
Figure 7-3. Designing in different densities
use
49304,N
to send the number to the printer.
10010
and 255 decimal to the printer. See "Prob-
128
with dots on graph paper, but before
figure
High-speed
double
the following subroutine in any
10000.
Low-speed
Double
The program
49