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USB function
Receive SOF
Switch to FIFO
Receive OUT token
Receive data from the host
Receive data
error?
Yes
Set EP3o normal
receive status to 1
(Set internal EP3o TS to 1)
Receive SOF
Switch to FIFO
Receive OUT token
Receive data from the host
Receive data
error?
Yes
Set EP3o normal
receive status to 1
(Set Internal EP3o TS to 1
)
Figure 15.21 EP3o Isochronous-Out Transfer Operation
B-side UIFR1/EP3oTS, EP3oTF update
FIFO A
No
Set EP3o abnormal
receive status to 1
(Set internal EP3o TF to 1)
A-side UIFR1/EP3oTS, EP3oTF update
FIFO B
No
Set EP3o abnormal
receive status to 1
(Set Internal EP3o TF to 1)
Firmware
Start of Frame
Clear the SOF packet
detection flag
(Clear SOF of UIFR3 to 0)
Read USB time stamp
registers H and L
(UTSRH and UTSRL)
FIFO B
Read EP3o statis
(Read EP3o TS and
EP3o TF of UIFR1)
Read USB endpoint
receive data size
register 3o (UESZ3o)
Read data from the USB
endpoint data register 3o
(UEDR3o)
Start of Frame
Clear the SOF packet
detection flag
(Clear SOF of UIFR3 to 0)
Read USB time stamp
registers H and L
(UTSRH and UTSRL)
FIFO A
Read EP3o status
(Read EP3o TS and
EP3o TF of UIFR1)
Read USB endpoint
receive data size
register 3o (UESZ3o)
Read data from the USB
endpoint data register 3o
(UEDR3o)
Rev. 3.0, 10/02, page 507 of 686
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