Product manual

Spinpoint M9TU-USB 3.0 Product Manual REV 1.0
63
USB INTERFACE AND USB COMMANDS
Table 6-10: Test Mode Selectors
6.3.6.3.11 Set Interface (Request Code 11)
This request allows the host to select an alternate setting for the specified interface.
Some USB devices have configurations with interfaces that have mutually exclusive settings. This request
allows the host to select the desired alternate setting. If a device only supports a default setting for the specified
interface, then a STALL may be returned in the Status stage of the request. This request cannot be used to change
the set of configured interfaces (the SetConfiguration() request must be used instead).
If the interface or the alternate setting does not exist, then the device responds with a Request Error. If wLength
is non-zero, then the behavior of the device is not specified.
Default state: Device behavior when this request is received while the device is in the Default state is not
specified
.
Address state: The device must respond with a Request Error.
Configured state: This is a valid request when the device is in the Configured state.
6.3.6.3.12 Synch Frame (Request Code 12)
This request is used to set and then report an endpoint’s synchronization frame.
When an endpoint supports isochronous transfers, the endpoint may also require per-frame transfers to vary in
size according to a specific pattern. The host and the endpoint must agree on which frame the repeating pattern
begins. The number of the frame in which the pattern began is returned to the host.
If a high-speed device supports the Synch Frame request, it must internally synchronize itself to the zeroth
microframe and have a time notion of classic frame. Only the frame number is used to synchronize and reported
by the device endpoint (i.e., no microframe number). The endpoint must synchronize to the zeroth microframe.
This value is only used for isochronous data transfers using implicit pattern synchronization. If wValue is non-
zero or wLength is not two, then the behavior of the device is not specified.
If the specified endpoint does not support this request, then the device will respond 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: The device shall respond with a Request Error.
Configured state: This is a valid request when the device is in the Configured state.