Texas Instruments OMAP5912 Reference Manual page 1452

USB Device Controller
Figure 23. Typical Operation for USB Device State Changed Interrupt Handler
Device state changed
handler
Read DEVSTAT
register (new value),
read DS_MEM
(previous value).
DEVSTAT.
ATT changed?
No
DEVSTAT.
USB_Reset or
DEF changed?
No
DEVSTAT.
SUS changed?
No
DEVSTAT.
R_Wk_Ok
changed?
No
DEVSTAT.
CFG changed
?
No
DEVSTAT.
ADD changed?
No
Save DEVSTAT
in DS_MEM for
next DS_CHG interrupt.
End of device state
changed handler
160 Universal Serial Bus (USB)
Yes
Device state must be
at least attached at
this point.
Yes
Device state must be
at least default at this
point.
Yes
Inform application that
a set/clear device
Yes
feature has modified
the remote wake-up
enable function.
Yes Yes
DEVSTAT.
CFG = 1?
Must be
not
No
configured
yet
Yes
DEVSTAT.
ADD = 1?
Application-specific
No
default state transition
Yes
Yes
DEVSTAT.
ADD = 1?
Application-specific
No
action to handle
addressed state to
default state transition
Attached/
unattached
handler
USB reset
handler
Suspend/
resume
handler
Set IRQ_SRC.
DS_CHG = 1 to
clear the interrupt.
Application-specific
action to handle
addressed state to
configured state to
transition
Application-specific
action to handle
configured state to
addressed state
transition
action to handle
configured state to
Action-specific
action to handle default
state addressed
state transsition
IRQ_SRC.DS_CHG interrupt
flag is cleared inside the
attached/unattached, USB
reset and suspend/resume
handlers.
Set IRQ_SRC.
DS_CHG = 1 to
clear the interrupt.
Set IRQ_SRC.
DS_CHG = 1 to
clear the interrupt.
SPRU761A