IBM 5150 PC Technical Reference (6025005, August, 1981) (PDF)

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Game Control Adapter
The Game Control Adapter allows the system to attach paddles and
joysticks. Up to four paddles or two joysticks may be attached. In
addition, four input for switches are provided. Paddle and joystick
positions are determined by changing resistive values sent to the
adapter. The adapter plus system software converts the present
resistive value to a relative paddle orjoystick position. On receipt ofan
output signal, four timing circuits are started. By determining the time
required for the circuit to time out (a function of the resistance), the
paddle position can be determined. This card could be used as a general
purpose I/O card with four analog (resistive) inputs plus four digital
input points. This card fits into any ofthe five System Board I/O slots.
The game control interface cable attaches to the rear ofthe card which
protrudes through the rear panel of the System Unit.
Game Control Adapter Block Diagram
A9 - AO
'\ ..
../
CONVERT A RESISTIVE INPUT
I 10 ...
...
DECODE TO K
4 I
AEN .. INSTRUCTION RESISTANCE
lOW .. DIGITAL "
PU LSE
lOR ..
.--­
.....- TYPICAL FREQUENCY
07·00 OF 833 Ht
A
DATA BUS A
,r
8 BUFFER/ 4
... DRIVER "­ "
DIGITAL INPUTS
A
"
....
4 I
Figure 20. GAME CONTROL ADAPTER BLOCK DIAGRAM
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