Controller Hardware - AMD Am186 CC User Manual

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Table 18-5 USB Commands Handled by Device Software
Command
GET_DESCRIPTOR
SET_CONFIGURATION Device Configuration
SET_INTERFACE
SET_DESCRIPTOR
SYNC_FRAME
Device Class or
Vendor Specific
18.5.9.2 Commands Handled by the USB Peripheral Controller Hardware
Table 18-6 on page 18-28 describes the commands that do not require device software
handling. When these commands are detected by the USB peripheral controller, they are
handled entirely in hardware. The device software does have the ability to detect the
reception of any USB setup packet sent to it by the USB host, but it cannot monitor the
specific setup packet type when the command is handled solely by the controller hardware.
Universal Serial Bus (USB)
Parameters and
Data Passed
Device, Configuration,
or String Descriptor
Interface Alternate
Setting
Device, Configuration,
String, Interface, or
Endpoint Descriptor
Synchronization Frame IN
Various
Am186™CC/CH/CU Microcontrollers User's Manual
Data
Results
Direction
The device software, upon detecting this
command, should return all of the data associated
with the particular descriptor that was requested.
IN
Because this controller allows the endpoint
parameters to be programmed at any time, an un-
limited number of descriptors can be supported.
The device software, upon detecting this
command, should configure all of the endpoints
OUT with the applicable USB parameters based on the
descriptor information that was passed to the host
during the GET_DESCRIPTOR command.
The device software, upon detecting this
command, should configure the endpoints
associated with the specified interface, for the
OUT
requested alternate setting, based on the
descriptor information that was passed to the host
during the GET_DESCRIPTOR command.
The device software, upon detecting this
OUT command, should accept a new descriptor from
the USB host.
The device software, upon detecting this
command, should return the frame number in
which an isochronous, IN endpoint begins its data
pattern.
The device software should service the
commands that it has been programmed to
handle. If the device software does not recognize
a particular command it should clear the
IN and EP_NOT_STALLED bit in the CNTCTL register to
OUT direct the controller hardware to return the stalled
handshake in the data stage. (The
NEW_COMMAND bit must be cleared at the
same time, or clearing the EP_NOT_STALLED bit
has no effect.)
18-27