Datasheet

Intel

Pentium

4 Processor in the 423-pin Package

7.0 Features

7.1 Power-On Configuration Options

Several configuration options can be configured by hardware. The Intel

Pentium

4 Processor in

the 423-pin Package sample its hardware configuration at reset, on the active-to-inactive transition

of RESET#. For specifications on these options, please refer to Table 34.

The sampled information configures the processor for subsequent operation. These configuration

options cannot be changed except during another reset. All resets reconfigure the processor; for

reset purposes, the processor does not distinguish between a “warm” reset and a “power-on” reset.

NOTE:

1. Asserting this signal during RESET# will select the corresponding option.

7.2 Clock Control and Low Power States

The use of AutoHALT, Stop-Grant, Sleep, and Deep Sleep states is allowed in Pentium 4 processor

based systems to reduce power consumption by stopping the clock to internal sections of the

processor, depending on each particular state. See Figure 27 for a visual representation of the

processor low power states.

7.2.1 Normal State—State 1

This is the normal operating state for the processor.

7.2.2 AutoHALT Powerdown State—State 2

AutoHALT is a low power state entered when the processor executes the HALT instruction. The

processor will transition to the Normal state upon the occurrence of SMI#, BINIT#, INIT#, or

LINT[1:0] (NMI, INTR). RESET# will cause the processor to immediately initialize itself.

The return from a System Management Interrupt (SMI) handler can be to either Normal Mode or

the AutoHALT Power Down state. See the Intel Architecture Software Developer's Manual,

Volume III: System Programmer's Guide for more information.

Table 34. Power-On Configuration Option Pins

Configuration Option Pin

Output tristate SMI#

Execute BIST INIT#

In Order Queue pipelining (set IOQ depth to 1) A7#

Disable MCERR# observation A9#

Disable BINIT# observation A10#

APIC Cluster ID (0-3) A[12:11]#

Disable bus parking A15#

Symmetric agent arbitration ID BR0#