Information Technology Reference
In-Depth Information
movements and to select objects, but is not a good device to play games with; thus, a joystick
is typically used. The games port adapter supports up to two joysticks connected to the same
port. It has 15 pins, which are outlined in Table 10.1 and connects to the system via:
•
Lower eight bits of the data bus.
•
Lower 10 bits of the address bus.
•
IOR
and
IOW
.
Table 10.1
Game adapter connections
Pin
Description
Pin
Description
1
+5V
9
+5V
2
1st button for joystick A (BA1)
10
1st button for joystick B (BB1)
3
X-potentiometer of joystick A (AX)
11
X-potentiometer of joystick B (BX)
4
GND
12
GND
5
GND
13
Y-potentiometer of joystick B (BY)
6
Y-potentiometer of joystick A (AY)
14
2nd button for joystick B (BB1)
7
2nd button for joystick A (BA1)
15
+5V
8
+5V
Each joystick has two buttons, which are normally open circuit, and two potentiometers
which give a variable resistance from 0 W to 100 kW, to indicate the x- and y-position of the
joystick handle. Figure 10.1 shows its connections. An unpressed button corresponds to a
high level and a button press to a low level.
1
BA1
9
BB1
2
GND
10
3
GND
AX
11
BX
4
12
5
13
BB2
6
BY
BA2
14
AY
7
GND
GND
15
8
Joystick B
Joystick A
Figure 10.1
Joystick interface
