EP80579 Datasheet, PDF (1032/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
6. Attempts to write any other value into the Device PowerState field other than 00b
(D0 state) and 11b (D3 state) will complete normally without changing the current
value in this field.
Software performs the following sequence to put the EHC in the D3 state:
1. Software selectively suspends any enabled EHC ports.
2. Software reads back the selectively suspended ports to make sure the EHC has
completed the suspend request.
3. Software clears the Run bit.
4. Software reads back the USB 2.0 Status Register to verify that the EHC is halted.
5. Software reads and saves the contents of the PCI configuration registers for
restoring the context after transitioning back to the D0 state.
6. Software writes the Device PowerState field to the D3 state.
26.10.4
ACPI System States
The EHC behavior as it relates to other power management states in the system is
summarized in the following list:
• The System is always in the S0 state when the EHC is in the D0 state. However,
when the EHC is in the D3 state, the system may be in any power management
state (including S0).
• When in D0, the Pause feature (described above) enables dynamic CPU low-power
states to be entered.
• The PLL in the EHC is disabled when entering the S3-Cold/S4/S5 states (core power
turns off).
• All core-well logic is reset in the S3/S4/S5 states.
26.11
Interaction with Classic Host Controllers
The Enhanced Host Controller shares the two USB ports with two UHCI Classic Host
Controllers (cHCs). The cHC at Device 29: Function 0 shares ports 1 and 2 with the
EHC. There is very little interaction between the Enhanced and Classic controllers other
than the muxing control that is provided as part of the EHC.
Figure 26-1 depicts the USB Port Connections at a conceptual level. The dashed
rectangle indicates all of the logic that is part of the Enhanced Host Controller cluster.
Intel^® EP80579 Integrated Processor Product Line Datasheet
1032
August 2009
Order Number: 320066-003US