
SMSC DS – LPC47M14X 
Page 150 
Rev. 03/19/2001 
NAME 
REG OFFSET 
(hex) 
DESCRIPTION 
Fan2 Preload 
Register 
Default = 0x00 
 on VTR POR 
LED1 
Default = 0x00 
 on VTR POR 
5C 
(R/W) 
Fan Preload Register 2 
Bit[7:0] The FAN2 tachometer preload.  This is the initial 
value used in the computation of the FAN2 count.  
Writing this register resets the tachometer count. 
5D 
(R/W) 
LED1 
Bit[1:0] LED1 Control  
00=off 
01=blink at 1Hz rate with a 50% duty cycle (0.5 sec on, 
0.5 sec off) 
10=Blink at  HZ rate with a 25% duty cycle (0.5 sec on, 
1.5 sec off) 
11=on 
Bits[7:2] Reserved 
LED2 
Bit[1:0] LED2 Control  
00=off 
01=blink at 1Hz rate with a 50% duty cycle (0.5 sec on, 
0.5 sec off) 
10=Blink at  HZ rate with a 25% duty cycle (0.5 sec on, 
1.5 sec off) 
11=on 
Bits[7:2] Reserved 
Keyboard Scan Code 
Bit[0]  LSB of Scan Code 
   . . . 
   . . . 
   . . . 
Bit[7]  MSB of Scan Code 
Reserved – reads return 0 
LED2 
Default = 0x00 
 on VTR POR 
5E 
(R/W) 
Keyboard Scan 
Code 
Default = 0x00 
 on VTR POR 
5F 
(R/W) 
N/A 
60-7F 
(R) 
Note 1:
 If the EETI function is selected for this GPIO then both a high-to-low and a low-to-high edge will set the PME, 
SMI and MSC status bits. 
Note 2:
 The IRTX2 function can be used on this pin if the IR Location Mux bit in the Serial Port 2 IR Option register is 
set. 
Note 3:
 These pins default to an output and LOW on VCC POR and Hard Reset. 
Note 4:
  If the FDC function is selected on this  pin (nMTR1, nDS1, DRVDEN0, DRVDEN1) then bit 6 of the FDD 
Mode Register (Configuration Register 0xF0 in Logical Device 0) will override  bit 7 in the GPIO Control Register.   Bit 
7 of the FDD Mode Register will also affect the pin if the FDC function is selected. 
Note 5:
  The nIO_SMI pin is inactive when the internal group SMI signal is inactive and when the SMI enable bit 
(EN_SMI, bit 7 of the SMI_EN2 register) is ‘0’.  When the output buffer type is OD, nIO_SMI pin is floating when 
inactive; when the output buffer type is push-pull, the nIO_SMI pin is high when inactive. 
Note 6:
 Bits 2 and 3 of the PME_STS4 and SMI_STS4 registers, and bit 3 of the PME_STS5 register may be set on 
a VCC POR.  If GP32, GP33 and GP53 are configured as input, then their corresponding PME and SMI status bits 
will be set on a VCC POR
. Also, GP32 and GP33
 pins revert to their non-inverting GPIO 
input 
function when VCC is 
removed from the part.  These GPIOs cannot be used for PME wakeup when the part is under VTR power (VCC=0). 
Note 7:
 These bits are R/W but have no effect on circuit operation. 
Note 8:
 These bits when read indicate the current bit status. These bits are set to “0” by writing “0” to individual bit 
locations in this register. Producing an interrupt in the SER IRQ stream by setting these bits to “0” overrides other 
interrupt sources for the SER IRQ stream. No other functional logic in the LPC47M14X sets bits in this register.  
These bits are only cleared by writing a ‘1’ to the bit location.