Datasheet

Section 14 Universal Serial Bus (USB)
Rev.7.00 Dec. 24, 2008 Page 516 of 698
REJ09B0074-0700
14.5.8 Processing of USB Standard Commands and Class/Vendor Commands
(1) Processing of Commands Transmitted by Control Transfer
A command transmitted from the host by control transfer may require decoding and execution
of command processing by the firmware. Whether or not command decoding is required by the
firmware is indicated in table 14.5 below.
Table 14.5 Command Decoding by Firmware
Decoding not Necessary by Firmware Decoding Necessary by Firmware
Clear Feature
Get Configuration
Get Interface
Get Status
Set Address
Set Configuration
Set Feature
Set Interface
Get Descriptor
Synch Frame
Set Descriptor
Class/Vendor command
If decoding is not necessary by the firmware, command decoding and data stage and status
stage processing are performed automatically. No processing is necessary by the user. An
interrupt is not generated in this case.
If decoding is necessary by the firmware, the USB function module stores the command in the
EP0s FIFO. After normal reception is completed, the SetupTS flag in UIER0 is set and an
interrupt request is generated from the EXIRQx pin. In the interrupt routine, eight bytes of data
must be read from the EP0s data register (UEDR0s) and decoded by the firmware. The
necessary data stage and status stage processing should then be carried out according to the
result of the decoding operation.