ISO TX handler
Read byte from
application’s TX
buffer.
Loop count = 0?
No
Write byte to TX
FIFO (via DATA
Increment TX byte
count, decrement
loop count.
Update application
TX buffer count.
Yes
End of TX ISO handler
STAT_FLG.
MISS_IN
= 1 ?
Yes
No
Wish to resend
missed data?
Yes
Set
CTRL.CIR_EP to
clear the current
FIFO.
No
Set Loop_count to TX
ISO packet length
(max is endpoint size).
When a Missed_in occurs, missed
data are from TWO frames previous).
Application-
specific actions
to handle
missed in data
(Reload TX byte
count...).
Must put missed transmit data
into foreground ISO TX FIFO.
Clear both foreground and
background TX FIFO.
register).
USB Device Controller
1640
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Universal Serial Bus (USB)
Figure 29-83. Write Isochronous TX FIFO Data Flowchart