Intel 31244 PCI-X manual PCI-X Layout Guidelines, PCI Voltage Levels, PCI/X Voltage Levels

Intel® 31244 PCI-X to Serial ATA Controller

PCI-X Layout Guidelines

PCI-X Layout Guidelines 7

This section provides guidelines for designing with the Intel® 31244 PCI-X to serial ATA controller PCI/PCI-X (PCI/X) bus interface in your application. This chapter is divided as follows:

•PCI/X voltage levels

•clocking modes

•general layout guidelines

•layout guidelines for the different slot configurations using PCI-X

7.1PCI Voltage Levels

The Intel® 31244 PCI-X to serial ATA controller does not support a 5 V PCI signaling interface, it supports 3.3 V only. Supporting a 5 V PCI interface requires additional I/O level translation circuitry. Table 18 is provided as a reference for the PCI/X signaling levels. A complete PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0a may be found on the www.pcisig.com website.

Table 18.	PCI/X Voltage Levels
	Symbol	Parameter	Minimum	Maximum	Units
	VIL3	Input Low Voltage (PCI-X)	-0.5	0.35 VCC33	Voltage
	VIH3	Input High Voltage (PCI-X/PCI)	0.5 VCC33	VCC33 + 0.5 V	Voltage
	VIL4	Input Low Voltage (PCI)	-0.5	0.3 VCC33	Voltage
	VOL3	Output Low Voltage (PCI-X)		0.1 VCC33	Voltage
	VOH3	Output HIGH Voltage (PCI-X)	0.9 VCC33		Voltage

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