Preparing for Transfers
13-84
Figure 13–12. Prepare for USB RX Transfer Routine
Prepare for USB
RX transfers
routine
Device is
ready to receive
data for
EPn ?
Write EP_NUM register:
– EP_NUM.EP_Num = n
– EP_NUM.EP_Dir = 0
– EP_NUM.EP_Sel = 0
– EP_NUM.Setup_Sel = 0
Set CTRL.
Set_FIFO_En
Any OUT
endpoint
configured ?
(EPn)
Another
OUT endpoint
configured ?
(EPn)
Yes
End of prepare for
USB RX transfers
routine
Yes
Note: This applies to all non-
ISO endpoints, with or
without DMA.
No
No
Yes
This enables both
FIFOs if double-buffering
is used.