LPC47B272-MS SMSC, LPC47B272-MS Datasheet - Page 125

• 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

The game port register is a read-only register. However, writing to the game port resets the RC time
constant pins (TIMA, B) to zero. The reset of the time constant pins occur on the “back” edge of the
write signal (when the write signal goes from its active state to its inactive state).
The game port read (JOYR) will be an IO read to the address programmed into the base IO address in
Logical Device 9.
The game port write (JOYW) will be an IO write to the address programmed into the base IO address in
Logical Device 9.
Minimum Rise Time
The fastest rise time on the RC constant pins (minimum RC time constant) for the game port is 20usec.
Power Control Register
Bit 2 in the Power Control Register (CR22) is the power control bit for the game port. This bit has the
same function as the activate bit for logical device 9 and shadows the activate bit. The activate bit also
shadows the power control bit 2.
VREF Pin
The LPC47B27x has a reference voltage pin input on pin 44 of the part. This reference voltage can be
connected to either a 5V supply or a 3.3V supply. It is used for the game port.
The reference voltage is used in the game port logic so that the joystick trigger voltage is 2/3 VREF
where VREF is either 5V or 3.3V. This is to preserve joystick compatibility by maintaining the RC time
constant reset trigger voltage of 3.3V (nominal) with VREF=5V (nominal), if required.
SMSC LPC47B27x
- 125 -
Rev. 04-17-07
DATASHEET