Radio Shack TRS-80 - Chapter 10: FOR-NEXT Loops; The FOR-NEXT Loop

JOYSTICKS
The joysticks
are two
identical assemblies
which will plug into
either P3 or
P4.
Figure
16
shows a
schematic
of the joystick
assembly. It
consists simply
of
a
push
button switch
for the
fire switch
and the
dual
potentiometers
connected by a
mechanical assembly.
The
mechanical assembly
causes
both
potentiometers
to be
changed at the
same time.
This
gives the
effect
of
a
two-dimensional control.
The
potentiometers
are connected so
that 5 volts is
applied to one
side of
the variable
resistor, and
ground is
connected to the
other. This allows
the
center wiper
to vary
from to 5 volts as
the
handle
is
moved.
The push
button switch
merely
provides
a
momentary ground
contact
for an input signal.
WHITE
+5V
YELLOW
GREEN
RED
BLACK
A
AA/J 3
1
|
2 100K
AvJ
;
a
2 100K
"1
GND
LUG
-o
9
GND
FIGURE 16.
JOYSTICK
SCHEMATIC
40