Product manual

Spinpoint M9TU-USB 3.0 Product Manual REV 1.0
59
USB INTERFACE AND USB COMMANDS
Some USB devices have configurations with interfaces that have mutually exclusive settings. This request
allows the host to determine the currently selected alternate setting.
If wValue or wLength are not as specified above, then the device behavior is not specified. If the interface
specified does not exist, then the device responds with a Request Error.
Default state: Device behavior when this request is received while the device is in the Default state is
not specified.
Address state: A Request Error response is given by the device.
Configured state: This is a valid request when the device is in the Configured state.
6.3.6.3.6 Get Status (Request Code 0)
This request returns status for the specified recipient.
The Recipient bits of the bmRequestType field specify the desired recipient. The data returned is the current
status of the specified recipient.
If wValue or wLength are not as specified above, or if wIndex is non-zero for a device status request, then the
behavior of the device is not specified.
If an interface or an endpoint is specified that does not exist, then the device responds with a Request Error.
Default state: Device behavior when this request is received while the device is in the Default state is not
specified.
Address state: If an interface or an endpoint other than endpoint zero is specified, then the device
responds with a Request Error.
Configured state: If an interface or endpoint that does not exist is specified, then the device responds
with a Request Error.
A GetStatus() request to a device returns the information shown in Figure 6-33.
Figure 6-33 Information Returned by a GetStatus() Request to a Device
The Self Powered field indicates whether the device is currently self-powered. If D0 is reset to zero, the device
is bus-powered. If D0 is set to one, the device is self-powered. The Self Powered field may not be changed by the
SetFeature() or ClearFeature() requests.
The Remote Wakeup field indicates whether the device is currently enabled to request remote wakeup. The
default mode for devices that support remote wakeup is disabled. If D1 is reset to zero, the ability of the device
to signal remote wakeup is disabled. If D1 is set to one, the ability of the device to signal remote wakeup is
enabled. The Remote Wakeup field can be modified by the SetFeature() and ClearFeature() requests using the
DEVICE_REMOTE_WAKEUP feature selector. This field is reset to zero when the device is reset.
A GetStatus() request to an interface returns the information shown in Figure 6-34.
Figure 6-34: Information Returned by a GetStatus() Request to an Interface