
events are enabled. Note that the keyboard and mouse isolation bits only prevent the internal 8042 in the part from 
setting these status bits. 
Case 1: Keyboard and/or Mouse Powered by VTR 
The KBD and/or MOUSE status bits will be set upon a VTR POR if the keyboard and/or mouse are powered by VTR.  
In this case, an IO_PME# will not be generated, since the keyboard and mouse PME enable bits are reset to zero on 
a VTR POR. The BIOS software needs to clear these PME status bits after power-up. 
Case 2: Keyboard and/or Mouse Powered by VCC 
The KBD and/or MOUSE status bits will be set upon a VCC POR if the keyboard and/or mouse are powered by VCC.  
In this case, an IO_PME# will be generated if the enable bits were set for wakeup, since the keyboard and mouse 
PME enable bits are VTR powered.  Therefore, if the keyboard and mouse are powered by VCC, the enable bits for 
keyboard and mouse events should be cleared prior to entering a sleep state where VCC is removed (i.e., S3) to 
prevent a false PME from being generated. In this case, the keyboard and mouse should only be used as PME 
and/or wake events from the S0 and/or S1 states. The BIOS software needs to clear these PME status bits after 
power-up. 
7.12 GENERAL PURPOSE I/O 
SMSC DS – LPC47M192 
Page 113 
Rev. 03/30/05 
DATASHEET 
The LPC47M192 provides a set of flexible Input/Output control functions to the system designer through the 37 
independently programmable General Purpose I/O pins (GPIO).  The GPIO pins can perform basic I/O and many of 
them can be individually enabled to generate an SMI and a PME.  
7.12.1 GPIO PINS 
The following pins include GPIO functionality.  These pins are defined in the table below.  All GPIOs default to the 
GPIO function except for GP34 and GP35 which default to IRRX2 and IRTX2. 
GPIO PIN 
REG 
OFFS
ET 
(hex) 
GP10/J1B1 
VCC 
- 
- 
In 
23 
GP11/J1B2 
VCC 
- 
- 
In 
24 
GP12 /J2B1 
VCC 
- 
- 
In 
25 
GP13 /J2B2 
VCC 
- 
- 
In 
26 
GP14 /J1X 
VCC 
- 
- 
In 
27 
GP15 /J1Y 
VCC 
- 
- 
In 
28 
GP16 /J2X 
VCC 
- 
- 
In 
29 
GP17 /J2Y 
VCC 
- 
- 
In 
2A 
GP20/P17 
VCC 
- 
- 
In 
2B 
GP21/P16/nDS1 
VCC 
- 
- 
In 
2C 
GP22/P12/nMTR1 
VCC 
- 
- 
In 
2D 
GP24/SYSOPT 
VCC 
- 
- 
In 
2F 
GP25/MIDI_IN 
VCC 
- 
- 
In 
30 
GP26/MIDI_OUT 
VCC 
- 
- 
In 
31 
GP27/nIO_SMI 
VCC 
- 
- 
In 
32 
GP30/FAN_TACH2 
VCC 
- 
- 
In 
33 
GP31/FAN_TACH1 
VCC 
- 
- 
In 
34 
GP32/FAN2 
VCC 
Out – low 
Out– 
low 
GP33/FAN1 
VCC 
Out – low 
Out– 
low 
IRRX2/GP34 
VCC 
- 
- 
In 
37 
IRTX2/GP35 
VTR 
Out – low 
Out– 
low 
low 
GP36/nKBDRST 
VCC 
- 
- 
In 
39 
GP37/A20M 
VCC 
- 
- 
In 
3A 
GP40/DRVDEN0 
VCC 
- 
- 
In 
3B 
GP41/DRVDEN1 
VCC 
- 
- 
In 
3C 
GP42/nIO_PME 
VTR 
- 
- 
In 
3D 
GPIO REGISTER 
PIN# 
PIN NAME 
(Default Func/ 
Alternate Funcs) 
PWR 
WELL 
PCI 
RESET 
VCC 
POR 
VTR 
POR 
REG  
PCI 
RESET
VCC 
POR 
VTR 
POR 
SOFT 
RESET 
SMI/PME 
NOTES
32 
33 
34 
35 
36 
37 
38 
39 
41 
42 
43 
45 
46 
47 
50 
51 
52 
54 
GP10 
GP11 
GP12 
GP13 
GP14 
GP15 
GP16 
GP17 
GP20 
GP21 
GP22 
GP24 
GP25 
GP26 
GP27 
GP30 
GP31 
GP32 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
0x01 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
PME 
PME 
PME 
PME 
PME 
PME 
PME 
PME 
SMI/PME 
SMI/PME 
SMI/PME 
SMI/PME 
SMI/PME 
SMI/PME 
nIO_SMI/PME 
SMI/PME 
SMI/PME 
SMI/PME 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
In 
35 
0x00 
0x00 
1, 2 
55 
In 
36 
GP33 
0x00 
0x00 
0x01 
- 
SMI/PME
1, 2 
61 
62 
GP34 
GP35 
- 
- 
0x05 
0x04 
- 
- 
SMI 
- 
Out - 
38 
0x04 
0x04 
3, 4 
63 
64 
1 
2 
17 
GP36 
GP37 
GP40 
GP41 
GP42 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
0x01 
0x01 
0x01 
0x01 
0x01 
- 
- 
- 
- 
- 
- 
- 
- 
SMI/PME 
SMI/nIO_PME 
1