450NX datasheet(13/248 Pages) INTEL

13 / 248 page

Intel

® 450NX PCIset

2-1

Signal Descriptions

This chapter provides a detailed description of all signals used in any component in the Intel®

450NX PCIset.

2.1

Conventions

The terms assertion and deassertion are used extensively when describing signals, to avoid

confusion when working with a mix of active-high and active-low signals. The term assert, or

assertion, indicates that the signal is active, independent of whether the active level is

represented by a high or low voltage. The term deassert, or deassertion, indicates that the signal

is inactive.

The “#” symbol at the end of a signal name indicates that the active, or asserted state occurs

when the signal is at a low voltage level. When “#” is not present after the signal name the

signal is asserted when at the high voltage level.

When discussing data values used inside the chip set, the logical value is used; i.e., a data

value described as "1101b" would appear as "1101b" on an active-high bus, and as "0010b" on

an active-low bus. When discussing the assertion of a value on the actual pin, the physical

value is used; i.e., asserting an active-low signal produces a "0" value on the pin.

The following notations are used to describe the signal type:

The signal description also includes the type of buffer used for the particular signal:

Input pin

Output pin

I/O

Bidirectional (input/output) pin

Open drain output pin (other than AGTL+ signals)

AGTL+

Open drain AGTL+ interface.

PCI

PCI-compliant 3.3 V/5 V-tolerant interface

LVTTL

Low-voltage (3.3 V) TTL-compatible signals.

2.5V

2.5 V CMOS signals.

Analog

Typically a voltage reference or specialty power supply.

450NX Datasheet(PDF) 13 Page - Intel Corporation