Usb Controller Receive Operation Sequence (Separate Mode) - NEC uPD98502 User Manual

6.6.6.3 Separate mode
The following figure illustrates the receive operations performed by USB Controller in Separate Mode.
Figure 6-23. USB Controller Receive Operation Sequence (Separate Mode)
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CHAPTER 6 USB CONTROLLER
(1)
W aits data
(2)
R eceives data
from U SB
- C R C ve rify
- Bit S tuffing verify
- N R ZI de code
(3)
S tores the data from U S B to
receive F IFO
(4)
B uffer is remaining
in system memory
area ?
Y es
(8)
D M A transfers to
system memory
(9)
D ata S ize < M axP ?
N o
(10)
B uffer be comes full ?
N o
Preliminary User's Manual S15543EJ1V0UM
(5)
F etches new
buffer descriptor
N o
(6)
N o
E ncounte rs link po inter ?
Y es
(7)
U pdates P ool Information
R egisters
Y es
(11)
W rites R x indicatio n
(12)
Y es
U pdates write poin ter,
S ets R x completio n bit of
correspon ding End Point in
U G SR register