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ATARI Light Pen Operator's Manual
SECTION 2 - POSSIBLE USES OF THE LIGHT PEN
Menu selectionf which is a common use for the ATARI Light Pen> may
take many different forms. One form of light pen selection is
illustrated by the Keyboard Substitute programi provided as
Programming Example 3 (see Section 7). In this program^ the pen is
used to select the letter to be typed on the screen. Programming
Example 4« the Teaching Aid Program< uses the pen in two different
menus. The demonstration
program provided on the cassette uses the
pen as a menu selector as well as a graphics tool.
By using the ATARI Light Pen with programs you have written^ you can
form a picturei a plot« a set of letters or groups of instructions on
the television screen. With the pen«
you can point to one of those
items on the screen. The computer will read signals coming from the
pen and can interpret those signals so that it knows what action to
take next. As an example>
you can produce a list of the different
progams you have available on the diskette in your ATARI Disk Drive.
The list (or menu) might appear as shown in Figure 1.
SJCt RTREK
CHECKBOOK
BOEONCER
CHEC KER5
DUNGEONS
OND
DROGONS
PLOCE
THE POINT
OE
THE LIGHT
PEN
OGOINST
THE
BOH
TO
EOOD
THE PROGROM
Figure 1 - Sample Menu
When you follow the instruction at the bottom of the television
screeni
your program will sense that the switch in the tip of the
light pen is pressed and will call the light pen subroutine.
The pen can also serve as a teaching device when a student uses it
to select the correct answer from a multiple-choice set of answers
placed on the television screen. A form of this is demonstrated in
Programming Example 4, a Teaching Aid#
in Section 8.
In each of these programs# items are placed at various known locations
on the screen. When the light pen registers are read# the program
compares the values obtained there to the values known to represent
Possible Uses of the Light Pen
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