Intel E6540 HH80557PJ0534M User Manual

Product codes
HH80557PJ0534M
Page of 122
Datasheet
97
Features
The system can generate a STPCLK# while the processor is in the HALT powerdown 
state. When the system de-asserts the STPCLK# interrupt, the processor will return 
execution to the HALT state.
While in HALT Power powerdown, the processor processes bus snoops.
6.2.2.2
Extended HALT Powerdown State 
Extended HALT is a low power state entered when all processor cores have executed 
the HALT or MWAIT instructions and Extended HALT has been enabled via the BIOS. 
When one of the processor cores executes the HALT instruction, that logical processor 
is halted; however, the other processor continues normal operation. The Extended 
HALT Powerdown state must be enabled via the BIOS for the processor to remain within 
its specification.
The processor automatically transitions to a lower frequency and voltage operating 
point before entering the Extended HALT state. Note that the processor FSB frequency 
is not altered; only the internal core frequency is changed. When entering the low 
power state, the processor first switches to the lower bus ratio and then transitions to 
the lower VID.
While in Extended HALT state, the processor processes bus snoops.
The processor exits the Extended HALT state when a break event occurs. When the 
processor exits the Extended HALT state, it will resume operation at the lower 
frequency, transitions the VID to the original value and then changes the bus ratio back 
to the original value.
6.2.3
Stop Grant and Extended Stop Grant States
The processor supports the Stop Grant and Extended Stop Grant states. The Extended 
Stop Grant state is a feature that must be configured and enabled via the BIOS. Refer 
to the following sections for details about the Stop Grant and Extended Stop Grant 
states. 
6.2.3.1
Stop Grant State 
When the STPCLK# signal 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 GTL+ signals receive power from the FSB, these signals should not be driven 
(allowing the level to return to V
TT
) for minimum power drawn by the termination 
resistors in this state. In addition, all other input signals on the FSB should be driven to 
the inactive state.
RESET# causes the processor to immediately initialize itself, but the processor will stay 
in Stop Grant state. A transition back to the Normal state occurs with the de-assertion 
of the STPCLK# signal.
A transition to the Grant Snoop state occurs when the processor detects a snoop on the 
While in the Stop Grant State, SMI#, INIT#, and LINT[1:0] is 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 processes a FSB snoop.