RJ80535 Intel, RJ80535 Datasheet - Page 12

• Manufacturer Part Number: RJ80535
• Description: Pentium M Processor
• Manufacturer: Intel

Low Power Features
2.1.3
2.1.4
12
While in AutoHALT Powerdown state, the processor will process bus snoops. Stop-Grant State
When the STPCLK# pin is asserted, the Stop-Grant state of the processor is entered 20 bus clocks
after the response phase of the processor-issued Stop-Grant Acknowledge special bus cycle.
Since the AGTL+ signal pins receive power from the system bus, these pins should not be driven
(allowing the level to return to V
state. In addition, all other input pins on the system bus should be driven to the inactive state.
RESET# will cause the processor to immediately initialize itself, but the processor will stay in
Stop-Grant state. A transition back to the Normal state will occur with the deassertion of the
STPCLK# signal. When re-entering the Stop-Grant state from the Sleep state, STPCLK# should be
deasserted ten or more bus clocks after the de-assertion of SLP#.
A transition to the HALT/Grant Snoop state will occur when the processor detects a snoop on the
system bus (see
assertion of the SLP# signal.
While in the Stop-Grant state, SMI#, INIT# and LINT[1:0] will be latched by the processor, and
only serviced when the processor returns to the Normal state. Only one occurrence of each event
will be recognized upon return to the Normal state.
While in Stop-Grant state, the processor will process snoops on the system bus and it will latch
interrupts delivered on the system bus.
The PBE# signal can be driven when the processor is in Stop-Grant state. PBE# will be asserted if
there is any pending interrupt latched within the processor. Pending interrupts that are blocked by
the EFLAGS.IF bit being clear will still cause assertion of PBE#. Assertion of PBE# indicates to
system logic that it should return the processor to the Normal state
HALT/Grant Snoop State
The processor will respond to snoop or interrupt transactions on the system bus while in Stop-Grant
state or in AutoHALT Power Down state. During a snoop or interrupt transaction, the processor
enters the HALT/Grant Snoop state. The processor will stay in this state until the snoop on the
system bus has been serviced (whether by the processor or another agent on the system bus) or the
interrupt has been latched. After the snoop is serviced or the interrupt is latched, the processor will
return to the Stop-Grant state or AutoHALT Power Down state, as appropriate.
Sleep State
The Sleep state is a low power state in which the processor maintains its context, maintains the
phase-locked loop (PLL), and has stopped all internal clocks. The Sleep state can only be entered
from Stop-Grant state. Once in the Stop-Grant state, the processor will enter the Sleep state upon
the assertion of the SLP# signal. The SLP# pin should only be asserted when the processor is in the
Stop-Grant state. SLP# assertions while the processor is not in the Stop-Grant state are out of
specification and may result in unapproved operation.
Snoop events that occur while in Sleep state or during a transition into or out of Sleep state will
cause unpredictable behavior.
In the Sleep state, the processor is incapable of responding to snoop transactions or latching
interrupt signals. No transitions or assertions of signals (with the exception of SLP#, DPSLP# or
RESET#) are allowed on the system bus while the processor is in Sleep state. Any transition on an
input signal before the processor has returned to Stop-Grant state will result in unpredictable
behavior.
Section
2.1.3). A transition to the Sleep state (see
CCP
) for minimum power drawn by the termination resistors in this
Intel
®
Pentium
Section
2.1.4) will occur with the
®
M Processor Datasheet