Intel C2518 FH8065501516710 Data Sheet

Intel

®

 Atom™ Processor C2000 Product Family for Microserver

Datasheet, Vol. 2 of 3

September 2014

274

Order Number: 330061-002US

The USB controller supports the power management features described in this section. 

The EHC only supports the ACPI D0 (Fully On) and D3 (Fully Off) device power states 

and does not support the D1 and D2 intermediate power states. Concerning the device 

power states:

• The EHC hardware does not inherently consume any more power when in the D0 

state than in the D3 state. However, the software is required to suspend or disable 

all ports before entering the D3 state such that the maximum power consumption 

is reduced.

• In the D0 state, all implemented EHC features are enabled.
• In the D3 state, accesses to the EHC memory-mapped I/O range do master abort. 

Since the debug port uses the same memory range, the debug port is only operational 

when the EHC is in the D0 state.

• In the D3 state, the EHC interrupt is not asserted for any reason. The internal 

Power Management Event (PME) signal indicates wake events, etc.

• When the Device Power State field is written to D0 from D3, an internal reset is 

generated. This is called the D3-to-D0 Reset.

• Attempts to write any other value into the Device Power State field other than 00b 

(D0 state) and 11b (D3 state) complete normally without changing the current 

value in this field.