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Intel
®
IXP42X product line and IXC1100 control plane processors—Universal Serial Bus (USB)
v1.1 Device Controller
Intel
®
IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
DM September 2006
478 Order Number: 252480-006US
• Number of bytes to transfer
• Index or offset
• Value: used to pass a variable-sized data parameter
• Device request
Table 171 shows a summary of all device requests. For a full description of host device
requests, see the Universal Serial Bus Specification Revision 1.1.
The UDC decodes most standard device commands with no intervention required by the
user. The following commands are not passed to the user are:
The Set Configuration and Set Interface commands are passed to the user to indicate
that the host set the specified configuration or interface and the software must take
any necessary actions. The Get Descriptor and Set Descriptor commands are passed to
the user to be decoded.
Because the Set Feature and Clear Feature commands are not passed on, the user is
not able decode the device remote wake-up feature commands. To solve this problem,
the status bit UDCCS0:DRWF indicates whether or not the device remote wake-up
feature is enabled. UDCCS0: DRWF is a read-only bit. When the bit is set to 1, the
device remote wake-up feature is enabled. When the bit is set to 0, the feature is not
enabled.
18.3.7 UDC Configuration
In response to the GET_DESCRIPTOR command, the user device sends back a
description of the UDC configuration. The UDC can physically support more data
channel bandwidth than the USB specification allows.
Table 171. Host Device Request Summary
Request Name
SET_FEATURE Enables a specific feature such as device remote wake-up or endpoint stalls.
CLEAR_FEATURE Clears or disables a specific feature.
SET_CONFIGURATION
Configures the UDC for operation. Used after a reset of the Intel XScale
®
processor or after a reset has been signalled via the USB.
GET_CONFIGURATION Returns the current UDC configuration to the host.
SET_DESCRIPTOR
Sets existing descriptors or add new descriptors. Existing descriptors include:
• Device•Configuration
•String•Interface
•Endpoint
GET_DESCRIPTOR Returns the specified descriptor, if it exists.
SET_INTERFACE Selects an alternate setting for the UDC’s interface.
GET_INTERFACE Returns the selected alternate setting for the specified interface.
GET_STATUS
Returns the UDC’s status including: remote wake-up, self-powered, data
direction, endpoint number, and stall status.
SET_ADDRESS Sets the UDC’s 7-bit address value for all future device accesses.
SYNCH_FRAME Sets then reports an endpoint’s synchronization frame.
• Set Address • Set Feature • Clear Feature
• Get Configuration • Get Status • Get Interface
•Sync Frame