Platform Design Checklist
R
314
Intel
®
855PM Chipset Platform Design Guide
14.8.7. FWH/LPC
Interface
ICH4-M FWH/LPC Interface – Resistor Recommendations
Pin Name
System
Pull up/Pull down
Series
Damping
Notes
9
FWH[3:0]/LAD[3:0] See
Notes
Extra pull ups not required. Connect directly
to FWH/LPC.
14.8.8. USB
Interface
ICH4-M USB Interface – Resistor Recommendations
Pin Name
System
Pull up/Pull down
Series
Damping
Notes
9
OC[5:0]#
Pul lup to V3ALWAYS
10 k
These signals are inputs into the ICH4-M and
must not be left floating. Pull up is required.
If an OC pin is not connected to a current
monitor or equivalent device for a given USB
port, an alternative mechanism should be
provided to handle a potential over current
condition.
USBRBIAS
USBRBIAS#
Pull down to GND
22.6
±
1%
Tie signals together and pull down through a
common 22.6
± 1% resistor.
The RBIAS resistor should be placed within 500
mils of the ICH4-M and avoid routing next to
clock pins.