IDT Power Management
Active State Power Management
PES12N3 User Manual
5 - 3
June 7, 2006
Notes
Figure 5.2 PES12N3 ASPM Link Sate Transitions
Active State Power Management
The operation of Active State Power Management (ASPM) is orthogonal to power management. Once
enabled by the ASPM field in the PCI Express® Link Control (PCIELCTL) register, ASPM link state transi-
tions are initiated by hardware without software involvement. The PES12N3 ASPM supports the required
L0s state as well as the optional L1 state.
The L0s Entry Timer (L0SET) field in the PCI Power Management Proprietary Control (PMPC) register
controls the amount of time L0s entry conditions must be met before the hardware transitions the link to the
L0s state. The L1 Entry Timer (L1SET) field in the PCI Power Management Proprietary Control (PMPC)
register controls the amount of time L1 entry conditions must be met before the hardware transitions the link
to the L1 state. If these conditions are met and the link is in the L0 or L0s states, then the hardware will
request a transition to the L1 state from its link partner. Note that L1 entry requests are only made by the
PES12N3 upstream port. If the link partner acknowledges the transition, then the L1 state is entered. Other-
wise the L0s state is entered.
L0
L0s
L1
L2/L3 Ready
L3
Summary of Contents for 89HPES12N3
Page 10: ...IDT Table of Contents PES12N3 User Manual iv June 7 2006 Notes...
Page 14: ...IDT List of Figures PES12N3 User Manual viii June 7 2006 Notes...
Page 36: ...IDT Clocking Reset and Initialization Reset PES12N3 User Manual 2 8 June 7 2006 Notes...
Page 40: ...IDT Link Operation Slot Power Limit Support PES12N3 User Manual 3 4 June 7 2006 Notes...
Page 50: ...IDT Switch Operation Switch Core Errors PES12N3 User Manual 4 10 June 7 2006 Notes...
Page 54: ...IDT Power Management Active State Power Management PES12N3 User Manual 5 4 June 7 2006 Notes...
Page 62: ...IDT Hot Plug and Hot Swap Hot Swap PES12N3 User Manual 6 8 June 7 2006 Notes...
Page 78: ...IDT SMBus Interfaces Slave SMBus Interface PES12N3 User Manual 7 16 June 7 2006 Notes...
Page 148: ...IDT Test and Debug SerDes Test Clock PES12N3 User Manual 10 6 June 7 2006...
Page 158: ...IDT JTAG Boundary Scan Usage Considerations PES12N3 User Manual 11 10 June 7 2006 Notes...