Configuration and Low Power Features
7.
Configuration and Low Power Features
7.1
Power-On Configuration Options
Several configuration options can be configured by hardware. The Mobile Intel Pentium 4
Processor-M samples its hardware configuration at reset, on the active-to-inactive transition of
RESET#. For specifications on these options, please refer to Table 41.
Frequency determination functionality will exist on engineering sample processors which means
that samples can run at varied frequencies. Production material will have the bus to core ratio
locked during manufacturing and can only be operated at the rated frequency.
The sampled information configures the processor for subsequent operation. These configuration
options cannot be changed except by another reset. All resets reconfigure the processor.
Table 41. Power-On Configuration Option Pins
Configuration Option
Pin1
Output tristate
SMI#
INIT#
A7#
Execute BIST
In Order Queue pipelining (set IOQ depth to 1)
Disable MCERR# observation
Disable BINIT# observation
APIC Cluster ID (0-3)
A9#
A10#
A[12:11]#
A15#
Disable bus parking
Symmetric agent arbitration ID
BR0#
NOTE: 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, Deep Sleep and Deeper Sleep states is allowed in
Mobile Intel Pentium 4 Processor-M based systems to reduce power consumption by stopping the
clock to internal sections of the processor, depending on each particular state. See Figure 35 for a
visual representation of the processor low-power states.
7.2.1
7.2.2
Normal State
This is the normal operating state for the processor.
AutoHALT Powerdown State
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#,
LINT[1:0] (NMI, INTR), or PSB interrupt message. RESET# will cause the processor to
immediately initialize itself.
Mobile Intel Pentium 4 Processor-M Datasheet
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INTEL [ INTEL ]
