Intel® Celeron® Processor for PGA370 up to 1.40 GHz on 0.13 µ Process
2.2.5
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 the 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.
While in the Sleep state, the processor is capable of entering its lowest power state, the Deep Sleep
state, by stopping the BCLK input (see Section 2.2.6). Once in the Sleep state, the SLP# pin can be
deasserted if another asynchronous system bus event occurs. The SLP# pin has a minimum
assertion of one BCLK period.
2.2.6
Deep Sleep State—State 6
The Deep Sleep state is the lowest power state the processor can enter while maintaining context.
The Deep Sleep state is entered by stopping the BCLK input (after the Sleep state was entered from
the assertion of the SLP# pin). The processor is in Deep Sleep state immediately after BCLK is
stopped. BCLK and BCLK# have to be separated by at least 0.2V during the Deep Sleep State.
Stopping of the BCLK input lowers the overall current consumption to leakage levels.
To re-enter the Sleep state, the BCLK input must be restarted. A period of 1 ms (to allow for PLL
stabilization) must occur before the processor can be considered to be in the Sleep state. Once in
the Sleep state, the SLP# pin can be deasserted to re-enter the Stop-Grant state.
While in Deep Sleep state, the processor is incapable of responding to snoop transactions or
latching interrupt signals. No transitions or assertions of signals are allowed on the system bus
while the processor is in Deep Sleep state. Any transition on an input signal before the processor
has returned to Stop-Grant state will result in unpredictable behavior.
Table 2. System Bus Clock in Deep Sleep Mode (Differential Mode only)
1
Symbol
Parameter
Min
0.4
0
Max
Units
Notes
V
V
BCLK Voltage Level when not active
BCLK# Voltage Level when not active
1.45
V
V
2
2
BCLK
–V
V
– 0.2
BCLK
BCLK
BCLK#
NOTES:
1. The values in this table are based on differential probe measurement of the Bclk.
2. The DC voltage level specified must be maintained when the system bus clock is not active (e.g., Deep Sleep
Mode). V has to be 200 mV less than V
.
BCLK
BCLK#
16
Datasheet
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