Signal Description
Table 2-14. Intel® 6700PXH 64-bit PCI Hub Signals and Default States (Sheet 3 of 3)
Signal
Power Plane
Type
During Reset
Immediately After Reset
SMBUS[3]
SMBUS[2]
SMBUS[1]
3.3V
3.3V
3.3V
I
I
I
High-Z
High-Z
High-Z
Undefined
Undefined
Undefined
2.11
PCI/PCI-X Interface
2.11.1
Initialization
The Intel® 6700PXH 64-bit PCI Hub is the source bridge for the PCI bus. The Intel® 6700PXH
64-bit PCI Hub senses the PxM66EN, Px133EN, and the PxPCIXCAP pins to decide the mode and
frequency of operation (when not in hot plug mode or when in one-slot-no-glue hot plug mode).
Table 2-15. PCI/PCI-X Mode and Frequency Encoding
PxPCIXCAP
(on the card)
PCI Capability
PCI-X Capability
PxM66EN
Px133EN
33 MHz
66 MHz
33 MHz
66 MHz
33 MHz
66 MHz
33 MHz
66 MHz
Not Capable
Not Capable
GND
Pull-up
X
X
GND
GND
PCI-X 66 MHz
PCI-X 66 MHz
PCI-X 100 MHz
PCI-X 100 MHz
PCI-X 133 MHz
PCI-X 133 MHz
GND
X
Pull-down
No Connect
GND
X
Pull-down
Pull-down
Pull-down
Pull-up
Pull-up
Capacitor to GND
Capacitor to GND
Capacitor to GND
Capacitor to GND
No Connect
GND
No Connect
Once the Intel® 6700PXH 64-bit PCI Hub identifies the capabilities of the PCI bus devices, it
drives the initialization pattern on the PxDEVSEL#, PxSTOP#, PxTRDY#, PxFRAME# and
PxIRDY# pins as per Table 2-16 to initialize the PCI bus devices to the proper mode and
frequency.
Table 2-16. PCI-X Initialization Pattern Driven by the Intel® 6700PXH 64-bit PCI Hub
(Sheet 1 of 2)
Clock Period
(ns)
Clock Freq
(MHz)
PxPERR#
PxDEVSEL#
PxSTOP#
PxTRDY#
Mode
Max
Min
Min
Max
Deasserted
Deasserted
Deasserted
Deasserted
Asserted
PCI
PCI
•
30
15
15
10
7.5
0
33
66
30
20
15
10
33
50
66
100
Deasserted
Deasserted
Deasserted
Deasserted
Deasserted
Deasserted
Deasserted
Asserted
Deasserted
Asserted
PCI-X Mode 1
66
Deasserted PCI-X Mode 1
Asserted PCI-X Mode 1
100
133
Asserted
Deasserted
Deasserted PCI-X Mode 1 Reserved1
Intel® 6700PXH 64-bit PCI Hub Datasheet
37
INTEL [ INTEL ]
