Stop-Grant State; Stop Clock State Machine - Intel E5410 - Cpu Xeon Quad Core 2.33Ghz Fsb1333Mhz 12M Lga771 Tray Datasheet

Figure 7-1.

Stop Clock State Machine

Normal State
Normal execution
STPCLK#
Asserted
Stop Grant State
BCLK running
Snoops and interrupts allowed
7.2.3

Stop-Grant State

When the STPCLK# pin is asserted, the Stop-Grant state of the processor is entered no
later than 20 bus clocks after the response phase of the processor issued Stop Grant
Acknowledge special bus cycle. By default, the Quad-Core Intel® Xeon® Processor
5400 Series will issue two Stop Grant Acknowledge special bus cycles, one for each die.
Once the STPCLK# pin has been asserted, it may only be deasserted once the
processor is in the Stop Grant state. All processor cores will enter the Stop-Grant state
once the STPCLK# pin is asserted. Additionally, all processor cores must be in the Stop
Grant state before the deassertion of STPCLK#.
Since the AGTL+ signal pins receive power from the front side bus, these pins should
not be driven (allowing the level to return to V
termination resistors in this state. In addition, all other input pins on the front side 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 the 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 de-
assertion of the STPCLK# signal.
A transition to the Grant Snoop state will occur when the processor detects a snoop on
the front side bus (see
100
HALT or MWAIT Instruction and
HALT Bus Cycle Generated
INIT#, BINIT#, INTR, NMI, SMI#,
RESET#, FSB interrupts
STPCLK#
De-asserted
Snoop Event Occurs
Snoop Event Serviced
Section 7.2.4.1).
Extended HALT or HALT State
BCLK running
Snoops and interrupts allowed
Snoop
Event
Occurs
Extended HALT Snoop or HALT
Snoop State
BCLK running
Service snoops to caches
Stop Grant Snoop State
BCLK running
Service snoops to caches
) for minimum power drawn by the
TT
Features
Snoop
Event
Serviced