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USB Device Controller
Figure 28.
Typical Operation for USB Suspend/Resume General USB Interrupt Handler
Suspend/resume
handler
DEVSTAT.SUS
= 1?
No
Inform
application of
resume.
Set IRQ_SRC.DS_CHG
=1
to clear the interrupt.
End of suspend/
resume handler
3.22
Parsing Non-ISO Endpoint-Specific Interrupt
166
Universal Serial Bus (USB)
Inform
application that
Yes
device is
entering
suspend.
The endpoint-specific interrupt ISR (also known as the non-isochronous
interrupt, on MPU Level 2 IRQ_30) must parse the interrupt identifier register
IRQ_SRC to determine the interrupts that are active (IRQ_SRC.EPN_RX,
IRQ_SRC.EPN_TX, or both). The two interrupts can be active at any time. The
ISR must then read the EPN_STAT register to determine the endpoint causing
the interrupt. For each direction, only one endpoint interrupt can be active at
a time (see Figure 29).
Set IRQ_SRC.DS_CHG
=1
to clear the interrupt.
Read
DEVSTAT.R_WK_OK
value.
Is remote wake-up
supported?
Is low power mode
supported?
SPRU761A
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