Intel Xeon Design Manual page 205

®
Table 13-4. Intel P64H2 Schematic Checklist (Sheet 2 of 5)
Checklist Items
PCIXCAP
PA_133EN
PB_133EN
IDSEL
3.3Vaux
PCI-X Specific Interface
PCIXCAP
Design Guide
Recommendations
• Conventional PCI cards connect this pin
directly to ground.
PCI-X 133 cards connect PCIXCAP to ground
through a 0.01 µ F ± 10% capacitor to provide
an AC signal return path.
PCI-X 66 cards connect PCIXCAP to ground
through a 10 k Ω ± 5% resistor in parallel with
a 0.01 µ F ±10% capacitor to provide an AC
signal return path.
• If implementing hot plug, PCIXCAP should be
pulled up to VCC3.3 through an 8.2 k Ω ± 5%
resistor.
• Enable PCI-X at 133 MHz for PCI Bus A. This
pin, when high, allows the PCI-X segment to
run at 133 MHz when PA_PCIXCAP is
sampled high. When low, the PCI-X segment
runs only at 100 MHz when PA_PCIXCAP is
sampled high.
• For 133 MHz (max) PCI-X capable slot:
8.2 k Ω ± 5% pull-up resistor to VCC3.3.
• For 100 MHz (max) PCI-X capable slot:
8.2 k Ω ± 5%pull-down resistor to ground.
• Enable PCI-X at 133MHz for PCI Bus B. This
pin, when high, allows the PCI-X segment to
run at 133 MHz when PB_PCIXCAP is
sampled high. When low, the PCI-X segment
runs only at 100 MHz when PB_PCIXCAP is
sampled high.
• For 133 MHz (max) PCI-X capable slot:
8.2 k Ω ± 5% pull-up resistor to VCC3.3.
• For 100MHz (max) PCI-X capable slot:
8.2 k Ω ± 5% pull-down resistor to ground.
• The series resistor on IDSEL should be 100 Ω .
• Leave this as unconnected on the PCI slots.
• Conventional PCI cards connect this pin
directly to ground.
PCI-X 133 cards connect PCIXCAP to ground
through a
0.01 µF ± 10% capacitor to provide an AC
signal return path. PCI-X 66 cards connect
PCIXCAP to ground through a
10 k Ω ± 5% resistor in parallel with a 0.01 µF ±
10% capacitor to provide an AC signal return
path.
• If implementing hot plug, PCIXCAP should be
pulled up to VCC_3.3 through an 8.2 k Ω
resistor. If not implementing hot plug, this
signal does not require a pull up or pull down.
Schematic Checklist
Comments
• See PCI-X Specification 1.0
recommendations for PCIXCAP
connection.
• Active only if PA_PCIXCAP pin
is high.
• Active only if PB_PCIXCAP pin
is high.
• This has changed from the
PCI-X 1.0 Specification. There
is a specification change that
allows for values other than the
original 2 k Ω value.
• The P64H2 does not support
PCI bus power management.
• See PCI-X Specification
recommendations for PCIXCAP
connection.
205