NEC Network Controller uPD98502 - Manual (Page 352)

CHAPTER 6 USB CONTROLLER
352 Preliminary User’s Manual S15543EJ1V0UM
6.6.6 USB controller receive processing
This section presents all of the processing performed by USB Controller at data receiving.
6.6.6.1 Normal mode
The following figure illustrates the receive operations performed by USB Controller in Normal Mode.
Figure 6-21. USB Controller Receive Operations (Normal Mode)
S tores the data from U S B to
receive F IF O
R e ceives data
from U S B
- C R C verify
- B it S tuffing verify
- N R ZI decode
E nco unters link poin ter ?
Y es
N o
D M A transfers to
system m em ory
W rites R x indication
U p dates w rite poin ter,
S ets R x com pletion bit of co rresponding
E ndP oint in U _G S R re gister
(1)
(2)
(5)
(7)
(8)
(9)
(3)
W aits data
F etches a new
buffer directory
U pdates pool
Inform ation R egisters
(4)
(6)