Intel BX80532PG3200D Data Sheet - Page 14

Low Power Features 2.1.1.3 2.1.1.4 2.1.1.5 2.1.2 2.1.2.1 2.1.2.2 While in AutoHALT Powerdown state, the dual-core processor will process bus snoops and snoops from the other core. The processor core will enter a snoopable sub-state (not shown in Figure 1) to process the snoop and then return to the AutoHALT Powerdown state. Core C1/MWAIT Powerdown State C1/MWAIT is a low-power state entered when the processor core executes the MWAIT(C1) instruction. Processor behavior in the MWAIT state is identical to the AutoHALT state except that Monitor events can cause the processor core to return to the C0 state. See the Intel® 64 and IA-32 Architectures Software Developer's Manuals, Volume 2A: Instruction Set Reference, A-M and Volume 2B: Instruction Set Reference, N-Z, for more information. Core C2 State Individual cores of the dual-core processor can enter the C2 state by initiating a P_LVL2 I/O read to the P_BLK or an MWAIT(C2) instruction, but the processor will not issue a Stop-Grant Acknowledge special bus cycle unless the STPCLK# pin is also asserted. While in the C2 state, the dual-core processor will process bus snoops and snoops from the other core. The processor core will enter a snoopable sub-state (not shown in Figure 1) to process the snoop and then return to the C2 state. Core C3 State Individual cores of the dual-core processor can enter the C3 state by initiating a P_LVL3 I/O read to the P_BLK or an MWAIT(C3) instruction. Before entering C3, the processor core flushes the contents of its L1 caches into the processor's L2 cache. Except for the caches, the processor core maintains all its architectural states in the C3 state. The Monitor remains armed if it is configured. All of the clocks in the processor core are stopped in the C3 state. Because the core's caches are flushed the processor keeps the core in the C3 state when the processor detects a snoop on the FSB or when the other core of the dual-core processor accesses cacheable memory. The processor core will transition to the C0 state upon occurrence of a Monitor event, SMI#, INIT#, LINT[1:0] (NMI, INTR), or FSB interrupt message. RESET# will cause the processor core to immediately initialize itself. Package Low-power State Descriptions Normal State This is the normal operating state for the processor. The processor remains in the Normal state when at least one of its cores is in the C0, C1/AutoHALT, or C1/MWAIT state. Stop-Grant State When the STPCLK# pin is asserted, each core of the dual-core processor enters the Stop-Grant state within 20 bus clocks after the response phase of the processor-issued Stop-Grant Acknowledge special bus cycle. Processor cores that are already in the C2, C3, or C4 state remain in their current low-power state. When the STPCLK# pin is deasserted, each core returns to its previous core low-power state. Since the AGTL+ signal pins receive power from the FSB, these pins should not be dterrivmeinna(tailolonwriensgistthoersleinvethl itsosrteattuer.nIntoaVddCCitPi)onfo,ramll ointihmeur minppuotwpeinr sdroanwtnhebyFSthBeshould be driven to the inactive state. 14 Datasheet