4.2 Pins That Require External Pullup Resistors
The following pins require external pullup resistors:
KDAT
KCLK
MDAT
MCLK
GP36/KBDRST if KBDRST function is used
GP37/A20M if A20M function is used
GP20/P17/DS1# If P17 function is used
GP21/P16/P12 if P16 or P12 function is used
GP22/P12/MTR1# if P12 function is used
GP27/IO_SMI# if IO_SMI# function is used as Open Collector Output
GP42/IO_PME# if IO_PME# function is used as Open Collector Output
SER_IRQ
GP40/DRVDEN0 if DRVDEN0 function is used as Open Collector Output
GP41/DRVDEN1/XCS0 if DRVDEN1 function is used as Open Collector Output
GP23, GP 34, GP35 and GP62 if IRQINx function is used
MTR0# if used as Open Collector Output
DS0# if used as Open Collector Output
DIR# if used as Open Collector Output
STEP# if used as Open Collector Output
WDATA# if used as Open Collector Output
WGATE# if used as Open Collector Output
HDSEL# if used as Open Collector Output
INDEX#
TRK0#
WRTPRT#
RDATA#
DSKCHG#
XRD#
XWR#
XOSEL if an external single-input 32 kHz clock source is used on the CLKI32 pin (10kΩ pull-up suggested)
GP55/nRTS2/SADR0 if SADR0 is used for strapping option (10kΩ pull-up suggested)
GP57/nDTR2/SADR1 if SADR1 is used for stapping option (10kΩ pull-up suggested)
SMSC DS – LPC47S45x
Page 18 of 259
Rev. 07/09/2001
DATASHEET
SMSC [ SMSC CORPORATION ]
