521 datasheet(87/96 Pages) INTEL

87 / 96 page

Datasheet

Features

6.2.3

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.

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 HALT/Grant Snoop state will occur when the processor detects a snoop on the

FSB (see Section 6.2.3).

While in the Stop-Grant State, SMI#, INIT#, BINIT# and LINT[1:0] will be 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 will process a FSB snoop.

Figure 6-1. Processor Low Power State Machine

Enhanced HALT or HALT State

BCLK running

Snoops and interrupts allowed

Normal State

Normal execution

HALT Snoop State

BCLK running

Service snoops to caches

Stop-Grant State

BCLK running

Snoops and interrupts allowed

Snoop

Event

Occurs

Snoop

Event

Serviced

INIT#, BINIT#, INTR, NMI, SMI#,

RESET#, FSB interrupts

STPCLK#

Asserted

STPCLK#

De-asserted

Snoop Event Occurs

Snoop Event Serviced

HALT or MWAIT Instruction and

HALT Bus Cycle Generated

Grant Snoop State

BCLK running

Service snoops to caches

521 Datasheet(PDF) 87 Page - Intel Corporation

521 Datasheet(HTML) 87 Page - Intel Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96

Datasheet Download

Link URL