Interrupt Service Routine (ISR) Flowcharts
13-110
Figure 13–32. SOF Interrupt Handler Flowchart
SOF ISR entry
ISO RX
Handler
End of SOF ISR
Application-
specific SOF
timing handling
Write 1 to
IRQ_SRC.SOF to clear
the IT.
Yes
Any ISO RX
endpoint
configured?
(EPn)
Write EP_NUM register:
– EP_NUM.EP_Num = n
– EP_NUM.EP_Dir = 0
– EP_NUM.EP_Sel = 1
– EP_NUM.Setup_Sel = 0
Write EP_NUM register:
– EP_NUM.EP_Num = n
– EP_NUM.EP_Dir = 0
– EP_NUM.EP_Sel = 0
– EP_NUM.Setup_Sel = 0
Another
ISO RX endpoint
configured?
(EPn)
Yes
No
Any ISO TX
endpoint
configured?
(EPn)
Write EP_NUM register:
– EP_NUM.EP_Num = n
– EP_NUM.EP_Dir = 1
– EP_NUM.EP_Sel = 1
– EP_NUM.Setup_Sel = 0
ISO TX
handler
Write EP_NUM register:
– EP_NUM.EP_Num = n
– EP_NUM.EP_Dir = 1
– EP_NUM.EP_Sel = 0
– EP_NUM.Setup_Sel = 0
Another
ISO TX endpoint
configured?
(EPn)
Yes
Yes
No
No
No
Caution: The local host must have
handled all ISO endpoints before next
start-of-frame.
6 WAIT
STATES
6 WAIT
STATES