Intel C2550 FH8065401488912 데이터 시트
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FH8065401488912
Intel
®
Atom™ Processor C2000 Product Family for Microserver
September 2014
Datasheet, Vol. 2 of 3
Order Number: 330061-002US
271
Volume 2—Universal Serial Bus (USB) 2.0—C2000 Product Family
EHC Initialization
14.7.3
Port Disable Override
The BIOS and the firmware control which USB ports are usable to the end-user. They
also designate which ports have non-removable devices versus which ports are
exposed to the end user. The system BIOS is expected to set these values upon boot
and resuming from Sx states.
14.7.4
Driver Initialization
For details, see Chapter 4 of the Enhanced Host Controller Interface Specification for
Universal Serial Bus, Revision 1.0. Some information from that chapter is presented
below.
14.7.5
EHC Resets
HOT
device power management state to the D0 state. The
effects of these resets are shown in
If the detailed register descriptions give exceptions to these rules, those exceptions
override these rules. This summary is provided to help explain the reasons for the reset
policies.
Table 14-6. EHC Reset Types
Type of Reset
Does Reset
Does not Reset
Comments
HCRESET
bit set.
Memory space
registers except
Structural Parameters
(which is written by
the BIOS).
Configuration
registers.
The HCRESET must only affect
registers that the EHCI driver controls.
PCI Configuration space and the
BIOS-programmed parameters are
not reset.
D3-to-D0 Reset
The software writes
the Device Power
State from D3
HOT
(11b) to D0 (00b).
Core power well
registers
(except the BIOS-
programmed
registers).
Suspend (SUS) power
well registers.
The BIOS-
The BIOS-
programmed Core
power well registers.
The D3-to-D0 transition must not
cause wake information (SUS well) to
be lost. Also, this transition must not
clear the BIOS-programmed registers
because the BIOS is not invoked
following the D3-to-D0 transition.