Intel Z670 AY80609007293AA Data Sheet
Product codes
AY80609007293AA
Power Management
20
Datasheet
3.1.1
Cx State Definitions
•
C0 State—Full On
This is the only state that runs software. All clocks are running and the processor
core is active. The processor can service snoops and maintain cache coherency in
this state. All power management for interfaces, clock gating, are controlled at the
unit level.
•
C1 State—Auto-Halt
The first level of power reduction occurs when the core processor executes an
Auto-Halt instruction. This stops the execution of the instruction stream and greatly
reduces the core processor’s power consumption. The core processor can service
snoops and maintain cache coherency in this state. The Processor North Complex
logic does not distinguish C1 from C0 explicitly.
•
C2 State—Stop Grant
The next level of power reduction occurs when the core processor is placed into the
Stop Grant state. The core processor can service snoops and maintain cache
coherency in this state. The North Complex only supports receiving a single Stop
Grant.
Entry into the C2 state will occur after the core processor requests C2 (or deeper).
Entry into the C2 state will occur after the core processor requests C2 (or deeper).
C2 state will be exited, entering the C0 state, when a break event is detected.
Processor must ensure that the DLLs are awake and the memory will be out of self-
refresh at this point.
•
C1E and C2E States
C1E and C2E states are transparent to the north complex logic. The C1E state is
the same as the C1 state, in that the core processor emits a HALT cycle when
entering the state. There are no other visible actions from the core processor.
The C2E state is the same as the C2 state, in that the core processor emits a Stop
The C2E state is the same as the C2 state, in that the core processor emits a Stop
Grant cycle when entering the state. There are no other visible actions from the
core processor.
•
C4 State—Deeper Sleep
In this state, the core processor shuts down its PLL and cannot handle snoop
requests. The core processor voltage regulator is also told to reduce the processor’s
voltage. During the C4 state, the North Complex will continue to handle traffic to
memory so long as this traffic does not require a snoop (i.e., no coherent traffic
requests are serviced).
The C4 state is entered by receiving a C4 request from the core processor/OS. The
The C4 state is entered by receiving a C4 request from the core processor/OS. The
exit from C4 occurs when the North Complex detects a snoopable event or a break
event, which would cause it to wake up the core processor and initiate the C0
sequence.