L7400 View Datasheet(PDF) - Intel
Part Name
Description
MFG CO.
L7400 Datasheet PDF : 91 Pages
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Low Power Features
Note:
2.1.2.5
2.1.2.6
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 FSB while the processor is in Sleep
state. Snoop events that occur while in Sleep state or during a transition into or out of
Sleep state will cause unpredictable behavior. Any transition on an input signal before
the processor has returned to the 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 an even lower power
state, the Deep Sleep state, by asserting the DPSLP# pin (See Section 2.1.2.5.). While
the processor is in the Sleep state, the SLP# pin must be deasserted if another
asynchronous FSB event needs to occur.
Deep Sleep State
The Deep Sleep state is entered through assertion of the DPSLP# pin while in the Sleep
state. BCLK may be stopped during the Deep Sleep state for additional platform level
power savings. BCLK stop/restart timings on Intel 945GM/GT/GMS/PM and 940GML
Express Chipset family based platforms with the CK410M clock chip are as follows:
• Deep Sleep entry: the system clock chip may stop/tristate BCLK within 2 BCLKs of
DPSLP# assertion. It is permissible to leave BCLK running during Deep Sleep.
• Deep Sleep exit: the system clock chip must drive BCLK to differential DC levels
within 2-3 ns of DPSLP# deassertion and start toggling BCLK within 10 BCLK
periods.
To re-enter the Sleep state, the DPSLP# pin must be deasserted. BCLK can be re-
started after DPSLP# deassertion as described above. A period of 15 microseconds (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 must be deasserted to re-enter
the Stop-Grant state.
While in Deep Sleep state, the processor is incapable of responding tosnoop
transactions or latching interrupt signals. No transitions of signals are allowed on the
FSB while the processor is in Deep Sleep state. When the processor is in Deep Sleep
state, it will not respond to interrupts or snoop transactions. Any transition on an input
signal before the processor has returned to Stop-Grant state will result in unpredictable
behavior.
Deeper Sleep State
The Deeper Sleep state is similar to the Deep Sleep state but reduces core voltage to
one of two lower levels. One lower core voltage level is achieved by entering the base
Deeper Sleep state. The Deeper Sleep state is entered through assertion of the
DPRSTP# pin while in the Deep Sleep state. The other lower core voltage level, the
lowest possible in the processor, is achieved by entering the Intel Enhanced Deeper
Sleep state of Deeper Sleep state. The Intel Enhanced Deeper Sleep state is entered
through assertion of the DPRSTP# pin while in the Deep Sleep only when the L2 cache
has been completely shut down. Refer to Section 2.1.2.6.1 and Section 2.1.2.6.2 for
further details on reducing the L2 cache and entering Intel Enhanced Deeper Sleep
state.
In response to entering Deeper Sleep, the Intel Core 2 Duo mobile processor will drive
the VID code corresponding to the Deeper Sleep core voltage on the VID[6:0] pins.
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Datasheet
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