Pentium
II
Processor with On-Die Cache – Low-Power Module
Datasheet
27
4.4.5
Quick Start State
This is a mode entered by the processor with the assertion of the STPCLK# signal when it is
configured for the Quick Start state (via the A15# strapping option). In the Quick Start state the
processor is only capable of acting on snoop transactions generated by the PSB priority device.
Because of its snooping behavior, Quick Start can only be used in single processor configurations.
A transition to the Deep Sleep state can be made by stopping the clock input to the processor. A
transition back to the Normal state (from the Quick Start state) is made only if the STPCLK# signal
is deasserted.
While in this state the processor is limited in its ability to respond to input. It is incapable of
latching any interrupts, servicing snoop transactions from symmetric bus masters, or responding to
FLUSH# and BINIT# assertions. In the Quick Start state, the processor will not respond properly
to any input signal other than STPCLK#, RESET#, or BPRI#. If any other input signal changes,
then the behavior of the processor will be unpredictable. No serial interrupt messages may begin or
be in progress while the processor is in the Quick Start state.
RESET# assertion will cause the processor to immediately initialize itself, but the processor will
stay in the Quick Start state after initialization until STPCLK# is deasserted.
4.4.6
HALT/Grant Snoop State
The processor will respond to snoop transactions on the PSB while in the Auto Halt, Stop Grant, or
Quick Start state. When a snoop transaction is presented on the system bus, the processor will enter
the HALT/Grant Snoop state. The processor will remain in this state until the snoop has been
serviced and the PSB is quiet. After the snoop has been serviced, the processor will return to its
previous state. If the HALT/Grant Snoop state is entered from the Quick Start state, then the input
signal restrictions of the Quick Start state still apply in the HALT/Grant Snoop state (except for
those signal transitions that are required to perform the snoop).
4.4.7
Sleep State
Important:
This state is not available on the module.
The Sleep state is a very low power state in which the processor maintains its context and the phase
locked loop (PLL) maintains phase lock. The Sleep state can only be entered from the Stop Grant
state. After entering the Stop Grant state the SLP# signal can be asserted, causing the processor to
enter the Sleep state. The SLP# signal is not recognized in the Normal state or the Auto Halt state.
The processor can be reset by the RESET# signal while in the Sleep state. If RESET# is driven
active while the processor is in the Sleep state, then SLP# and STPCLK# must immediately be
driven inactive to ensure that the processor correctly initializes itself.
Input signals (other than RESET#) may not change while the processor is in the Sleep state or
transitioning into or out of the Sleep state. Input signal changes at these times will cause
unpredictable behavior. Thus, the processor is incapable of snooping or latching any events in the
Sleep state.
While in the Sleep state the processor can enter its lowest power state, the Deep Sleep state.
Removing the processor’s input clock puts the processor in the Deep Sleep state. PICCLK may be
removed in the Sleep state.