L0
L2
L0s
L1
L3
L2/L3
Ready
Preliminary
Architecture
www.ti.com
Figure 13-12. Link State Transition to L1 State
13.2.12.2.1 L0s State
L0s is a lower power state enabled by Active State Power Management. Each device can control its
L0s transition on its transmitter. Receiver side is controlled by the remote device.
13.2.12.2.2 L1 State
The L1 state is reached either through ASPM timer mechanism or via the software initiated transition to
a D state other than the D0 state. In L1 state, the link is in idle state and both receiver and transmitter
in devices on both ends of a link are able to conserve energy.
13.2.12.2.3 L2/L3 Ready State
This state is a transitional state reached from L1 where from the link must either transition to L2 or to L3
state. The L3 state is a full power off state. The L2 state is also a power off state except that the WAKE
signal can be used by End Point devices to request power and clock from the system.
13.2.12.2.4 L2 State
The L2 state is appropriate when a device needs to monitor an external event while in deep power
down mode. In L2 state, auxiliary power is supplied and a minimal amount of current is drawn from the
power source. Almost all of the logic is devoid of power. To recover, the wake signal is used.
13.2.12.2.5 L3 State
In this state, device is supplied no power from the PCIe fabric. There is no mechanism to communicate
in L3 state. To recover, the system must re-establish power and reference clock followed by a
fundamental reset.
13.2.13 Relationship Between Device and Link Power States
The device D-states are correlated to the link power states. For each D state, there are specific states
that the PCIe link or interconnect can transition to.
shows the permissible state
combinations.
Table 13-11. Device Power States and Link Power States Relations
Downstream Device State
Permissible Upstream Device State
Permissible Link State
D0
D0
L0 (required),
L0s (required),
L1 ASPM (optional)
D1
D0 – D1
L1
D2
D0 – D2
L1
D3hot
D0 – D3hot
L1, L2/L3 Ready
D3cold
D0 – D3cold
L2aux, L3
1300Peripheral Component Interconnect Express (PCIe)
SPRUGX9 – 15 April 2011
© 2011, Texas Instruments Incorporated
Содержание TMS320C6A816 Series
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