Intel 31154 manual PCI/PCI-X Interface, PCI/PCI-X Voltage Levels, Interrupt Routing, Parameter

	PCI/PCI-X Interface
PCI/PCI-X Interface	5

This chapter provides guidelines for designing with the Intel® 31154 133 MHz PCI Bridge PCI/PCI-X bus interface in your application.

5.1PCI/PCI-X Voltage Levels

The Intel® 31154 133 MHz PCI Bridge supports the 5 V PCI signaling interface as well as 3.3 V. Table 6 is provided as a reference for the PCI/PCI-X signaling levels. A complete PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0a can be found on the www.pcisig.com website.

Table 6.	PCI/PCI-X Voltage Levels
	Symbol	Parameter	Minimum	Maximum	Units
	VIL3	Input low voltage (PCI-X)	-0.5	0.35 × VCC33	V
	VIH3	Input high voltage (PCI-X/PCI)	0.5 × VCC33	VCC33 + 0.5	V
	VIL4	Input low voltage (PCI)	-0.5	0.3 × VCC33	V
	VOL3	Output low voltage (PCI-X)		0.1 × VCC33	V
	VOH3	Output high voltage (PCI-X)	0.9 × VCC33		V

5.2Interrupt Routing

The 31154 does not use PCI INT lines (INTA, INTB, INTC and INTD). These pins are usually routed from the primary to secondary PCI buses, bypassing the bridge.

Intel® 31154 133 MHz PCI Bridge Design Guide Design Guide 29