LPC47B272-MS SMSC, LPC47B272-MS Datasheet - Page 124

• Manufacturer Part Number: LPC47B272-MS
• Description: IC CTRLR SUPER I/O LPC 100-QFP
• Manufacturer: SMSC

Specifications of LPC47B272-MS

• Controller Type: I/O Controller
• Interface: LPC
• Voltage - Supply: 3.3V
• Current - Supply: 15mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 100-QFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 638-1019

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.
The game port register is defined below. It is a runtime register located at the address programmed into
the base I/O address (GAME_PORT) in Logical Device 9.
Note:
When the activate bit in Logical Device 9 is cleared, it prevents the base I/O address for the game port
from being decoded.
Game Port Register
Register Location:
Default Value:
Attribute:
Size:
SMSC LPC47B27x
Button #2
Joystick 2
(J2B2)
JOYW
TIMA,B
OUTA,B
JOYR
D7
Register 0x60 is the high byte; 0x61 is the low byte. For example, to set the primary base
address to 1234h, write 12h into 0x60, and 34h into 0x61.
Joystick 2
Button #1
(J2B1)
D6
Joystick 1
Button #2
(J1B2)
D5
t1
<GAME_PORT>+0h System I/O Space
00h on VTR POR
Read-Only
8-bits
Joystick 1
Button #1
DATASHEET
(J1B1)
D4
- 124 -
Joystick 2
(OUT2B)
Y-Axis
D3
Joystick 2
(OUT2A)
X-Axis
D2
Joystick 1
(OUT1B)
Y-Axis
D1
Joystick 1
VREF
2
3
(OUT1A)
Rev. 04-17-07
X-Axis
VREF
D0