
SMSC DS – LPC47M14X 
Page 19 
Rev. 03/19/2001 
GP35, GP42, GP53, GP60 and GP61: 
 
Buffers powered by VTR. GP35 and GP53 have IRTX as the alternate function and their output buffers are 
powered by VTR so that the pins are always forced low when not used. GP42 is the nIO_PME pin, which is 
active under VTR. GP60 and GP61 have LED as the alternate function and the logic is able to control the pin 
under VTR. 
The IRTX pins (IRTX2/GP35 and GP53/TXD2(IRTX)) are powered by VTR so that they are driven low when VCC = 
0V with VTR = 3.3V.  These pins will remain low following a VCC POR until serial port 2 is enabled by setting the 
activate bit, at which time the pin will reflect the state of the transmit output of the Serial Port 2 block.  
The following list summarizes the blocks, registers and pins that are powered by VTR. 
 
USB Hub 
 
PME interface block 
 
PME runtime register block (includes all PME, SMI, GPIO, Fan and other miscellaneous registers)  
 
“Wake on Specific Key” logic 
 
LED control logic 
 
Fan Tachometers 
 
Pins for PME Wakeup:  
 
GP42/nIO_PME (output, buffer powered by VTR) 
 
nRI1 (input) 
 
GP50/nRI2 (input) 
 
GP52/RXD2(IRRX) (input) 
 
KDAT (input) 
 
MDAT (input) 
 
GPIOs (GP10-GP17, GP20-GP22, GP24-GP27, GP30-GP33, GP41, GP43, GP50-GP57, GP60, and 
GP61) – all input-only except GP53, GP60, and GP61.  See below. 
 
Other Pins 
 
 IRTX2/GP35 (output, buffer powered by VTR) 
 
 GP53/TXD2(IRTX) (output, buffer powered by VTR) 
 
 GP60/LED1 (output, buffer powered by VTR) 
 
 GP61/LED2 (output, buffer powered by VTR) 
5.8 
See the “Operational Description” section for the maximum current values. 
The maximum VTR current, I
TR
, is given with all outputs open (not loaded), and all inputs in a fixed state (i.e., 0V or 
3.3V).  The total maximum current for the part is the unloaded value PLUS the maximum current sourced by all pins 
that are driven by VTR.  The pins that are powered by VTR are as follows:  GP42/nIO_PME, IRTX2/GP35, 
GP53/TXD2(IRTX), GP60/LED1, GP61/LED2, and CLKI32.  These pins, if configured as push-pull outputs, will 
source a minimum of 6mA at 2.4V when driving.  
 
The maximum VCC current, I
CC
, is given with all outputs open (not loaded) , and all inputs in a fixed state 
(i.e., 0V or 3.3V).  
 
The maximum VREF current, I
REF
, is given with all outputs open (not loaded) , and all inputs in a fixed state 
(i.e., 0V or 3.3V). 
MAXIMUM CURRENT VALUES 
5.9 
The LPC47M14x offers support for Power Management Events (PMEs), also referred to as System Control Interrupt 
(SCI) events. The terms PME and SCI are used synonymously throughout this document to refer to the indication of 
an event to the chipset via the assertion of the nIO_PME output signal on pin 17.  See the “PME Support” section.
POWER MANAGEMENT EVENTS (PME/SCI)