CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
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(i) SET_INTERFACE() request
If wLength is other than the values shown in Table 12-3, if wIndex is other than the value set to the UF0
active interface number register (UF0AIFN), or if wValue is other than the value set to the UF0 active
alternative setting register (UF0AAS), a STALL response is made in the status stage.
•
Default state:
A STALL response is made in the status stage when the SET_INTERFACE() request
has been received.
•
Addressed state: A STALL response is made in the status stage when the SET_INTERFACE() request
has been received.
•
Configured state: Null packet is transmitted in the status stage when the SET_INTERFACE() request
has been received.
When the SET_INTERFACE() request has been correctly processed, an interrupt is issued. All the Halt
Features of the endpoint linked to the target Interface are cleared after the SET_INTERFACE() request
has been cleared. The data toggle of all the endpoints related to the target Interface number is always
initialized again to DATA0. When the currently selected Alternative Setting is to be changed by correctly
processing the SET_INTERFACE() request, the FIFO of the endpoint that is affected is completely cleared,
and all the related interrupt sources are also initialized.
When the SET_INTERFACE() request has been completed, the FIFO of all the endpoints linked to the
target Interface are cleared. At the same time, Halt Feature and Data PID are initialized, and the related
UF0 INT status n register (UF0ISn) is cleared to 0 (n = 0 to 4). (Only Halt Feature and Data PID are
cleared when the SET_CONFIGURATION request has been completed.)
12.3.2 Other requests
(1) Response and processing
The following table shows how other requests are responded to and processed.
Table 12-4. Response and Processing of Other Requests
Request
Response and Processing
GET_DESCRIPTOR String
Generation of CPUDEC interrupt request
GET_STATUS Interface
Automatic STALL response
CLEAR_FEATURE Interface
Automatic STALL response
SET_FEATURE Interface
Automatic STALL response
all SET_DESCRIPTOR
Generation of CPUDEC interrupt request
All other requests
Generation of CPUDEC interrupt request
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