Intel® Celeron® Processor up to 1.10 GHz
2.2.3
Stop-Grant State—State 3
The Stop-Grant state on the processor is entered when the STPCLK# signal is asserted.
Since the AGTL+ signal pins receive power from the system bus, these pins should not be driven
(allowing the level to return to VTT) for minimum power drawn by the termination resistors in this
state. In addition, all other input pins on the system bus should be driven to the inactive state.
BINIT# will not be serviced while the processor is in Stop-Grant state. The event will be latched
and can be serviced by software upon exit from Stop-Grant state.
FLUSH# will not be serviced during Stop-Grant 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.
A transition to the HALT/Grant Snoop state will occur when the processor detects a snoop on the
system bus (see Section 2.2.4). A transition to the Sleep state (see Section 2.2.5) will occur with the
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.
2.2.4
2.2.5
HALT/Grant Snoop State—State 4
The processor will respond to snoop transactions on the Celeron processor system bus while in
Stop-Grant state or in AutoHALT Power Down state. During a snoop transaction, the processor
enters the HALT/Grant Snoop state. The processor will stay in this state until the snoop on the Intel
Celeron processor system bus has been serviced (whether by the processor or another agent on the
Intel Celeron processor system bus). After the snoop is serviced, the processor will return to the
Stop-Grant state or AutoHALT Power Down state, as appropriate.
Sleep State—State 5
The Sleep state is a very 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 SLP# pin can be asserted, causing
the processor to enter the Sleep state. The SLP# pin is not recognized in the Normal or AutoHALT
states.
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# 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.
If RESET# is driven active while the processor is in the Sleep state, and held active as specified in
the RESET# pin specification, then the processor will reset itself, ignoring the transition through
Stop-Grant State. If RESET# is driven active while the processor is in the Sleep State, the SLP#
and STPCLK# signals should be deasserted immediately after RESET# is asserted to ensure the
processor correctly executes the Reset sequence.
Datasheet
17
INTEL [ INTEL ]
