Freescale Semiconductor TWR-MCF52259-Ethenet, User Manual, Page: 91 / 166

TM
The General USB Process
How Data is Transferred in USB
Frame
Transfer 1
Transaction
S
ta
rt
o
f F
ra
m
e
Transfer 2
Transaction 1
P
a
c
k
e
t 1
P
a
c
k
e
t 2
P
a
c
k
e
t 3
Transaction 2
P
a
c
k
e
t 1
P
a
c
k
e
t 2
P
a
c
k
e
t 3
Transaction 3
P
a
c
k
e
t 1
P
a
c
k
e
t 2
P
a
c
k
e
t 3
Transfer 3
Transaction 1
P
a
c
k
e
t 1
P
a
c
k
e
t 2
P
a
c
k
e
t 3
1500 bytes / 1 Ms
USB is a token-based (packet) standard. Data is transferred
between the host and the device in a series of frames, transfers,
transactions, and packets within1 Ms/1500 byte frames.
S
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