CHAPTER 6 USB CONTROLLER
356 Preliminary User’s Manual S15543EJ1V0UM
6.6.6.3 Separate modeThe following figure illustrates the receive operations performed by USB Controller in Separate Mode.Figure 6-23. USB Controller Receive Operation Sequence (Separate Mode)
Stores the data from USB to
receive FIFO
Receives data
from USB
- CRC verify
- Bit Stuffing ve rify
- NRZI decode
Buffer is remainin g
in system memory
area ?
Yes
No
DMA trans fers to
system memory
Writes Rx indication
Updates write pointer,
Sets Rx com pletion bit of
corresponding EndPoint in
UGSR register
(1)
(2)
(4)
(8)
(10)
(11)
(3)
Waits data
Fetches new
buffer descriptor
Encounters link pointer ?
Updates Pool Information
Registers
No
Yes
Data Size < MaxP ?
(9)
No
(5)
(6)
(7)
Buffer beco mes full ? (12)
Yes
Yes
No