Usb Control Transfers And Set-Address Request - Renesas M16C Series User Manual

M30240 Group
W h e n a n Iso ch ro n o u s T ra n sfe r is u se d :
S e le ctin g th e U S B IS O C o n tro l R e g iste r
b 7
0
Figure 3.30: Initializing USB Function Control Unit (4)

3.2.9 USB Control Transfers and SET-ADDRESS Request

Control transfers consist of the set-up stage, the data stage and the status stage. The data obtained
during the set-up stage determines which type of transfer (write, read, or data-less) occurs.
The SET_ADDRESS request is received in a read transfer from the host CPU in order to set the USB
address register (USBA). The USB Function Control unit uses this address for all later USB device
accesses.
Table 3.7 shows the composition of the SET_ADDRESS request and Figure 3.31 and Figure 3.32 show
the procedures for setting the device address. This routine should be placed in the Endpoint 0 interrupt
processing routine.
Table 3.7: SET_ADDRESS Request
0 byte
bm Request Type
00000000B
Rev.1.00 Sep 24, 2003 Page 317 of 360
C o n tin u e d fro m p re vio u s p a g e
b 0
U S B IS O C o n tro l R e g iste r
0 0 0 0 0
U S B IS O C
A U T O _ F L U S H B it
0 : A u to F IF O F lu sh d isa b le d
1 : A u to F IF O F lu sh e n a b le d
IS O _ U P D A T E B it
0 : IS O u p d a te d isa b le d
1 : IS O u p d a te e n a b le d
U S B T ra n sm it P ro ce s sin g
b Request
SET_ADDRESS
(Code: 05 )
16
Lower Position
A d d re s s
0 3 0 8
1 6
wValue
Device Address
Upper Position
Universal Serial Bus
7 byte
wIndex wlength
0 0