LPC47M192-NW Standard Microsystems (SMSC), LPC47M192-NW Datasheet - Page 126

• Manufacturer Part Number: LPC47M192-NW
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LPC47M192-NW

• Lead Free Status / RoHS Status: Compliant

The figure below illustrates the implementation of the game port logic in the LPC47M192.
Game software will write a byte to the game port to reset it, and then poll (read) the port until the x and y-axis RC time
constant pins (TIMA,B) time out (return to zero). The elapsed time indicates the resistance value of the potentiometer
and in turn, the position of the joystick.
The figure below illustrates the timing of the game port signals. The 556 timers will reset the outputs (OUTA,B) to
zero and the RC constant (TIMA,B) pins to zero when the RC constant (TIMA,B) inputs reach 2/3 of VREF as shown.
VREF is the voltage on pin 44, which is either 5V or 3.3V. See the “VREF Pin “ section.
SMSC DS – LPC47M192
JOYW
JOYR
Game Port
Register
Internal To LPC47M192
D0
D1
D2
D3
D4
D5
D6
D7
OUT1A
OUT1B
OUT2A
OUT2B
TRIG1A
TRIG1B
TRIG2A
TRIG2B
DATASHEET
556
556
TIM1A
TIM1B
TIM2A
TIM2B
Page 126
J1X
J1Y
J2X
J2Y
J1B1
J1B2
J2B1
J2B2
Vcc = 5V
X-Axis
Y-Axis
X-Axis
Y-Axis
Internal To Joysticks
Vcc = 5V
Vcc = 5V
Vcc = 5V
Vcc = 5V
Joystick 1 Button 1
Joystick 1 Button 2
Joystick 2 Button 1
Joystick 2 Button 2
Joystick 1
Joystick 2
Rev. 03/30/05