Platform Design Checklist
R
306
Intel
®
855PM Chipset Platform Design Guide
14.8. ICH4-M
Checklist
Note:
All inputs to the ICH4-M must not be left floating. Many GPIO signals are fixed inputs that must be
pulled up to different sources.
14.8.1.
ICH4-M Resistor Recommendations
ICH4-M – Resistor Recommendations
Pin Name
System
Pull up/Pull down
Series
Damping
Notes
9
PCI Resistor Recommendations
DEVSEL#
Pull up to Vcc3_3
8.2 k
FRAME#
Pull up to Vcc3_3
8.2 k
GPIO0/REQA#
GPIO1/REQB#/
REQ5#
Pull up to Vcc3_3
8.2 k
Each signal requires a pull up.
GPIO16 / GNTA#
See Notes
GNT[A] has an added strap function of “top
block swap”. This signal is sampled on the
rising edge of PWROK. By default, this signal is
HIGH or strap function is DISABLE.
Strap function can be enabled by pulling down
this signal to GND through a 1 k
resistor.
IRDY#
Pull up to Vcc3_3
8.2 k
LOCK#
Pull up to Vcc3_3
8.2 k
PERR#
Pull up to Vcc3_3
8.2 k
SERR#
Pull up to Vcc3_3
8.2 k
STOP#
Pull up to Vcc3_3
8.2 k
TRDY#
Pull up to Vcc3_3
8.2 k
REQ[4:0]#
Pull up to Vcc3_3
8.2 k
Each signal requires a pull up.
Interrupt Interface Resistor Recommendations
APICCLK
Pull down to GND
(If NOT Used)
Recommended to disable APICCLK and
APICD[1:0].
APICD[1:0]
Pull down to GND
(If NOT Used)
10 k
Recommended to disable APICCLK and
APICD[1:0]:
If XOR Chain Testing Is
NOT
Used: Pull down
the signals through a shared 10-k
resistor.
If XOR Chain Testing Is Used: Each signal
requires a separate 10-k
pull down resistor.
IRQ[15:14]
Pull up to Vcc3_3
8.2 k
-
10 k