Texas Instruments OMAP5912 Reference Manual page 1522

USB OTG Controller
Figure 50. OTG Interrupt Handler
OTG interrupt handler
Read OTG_IRQ_SRC
OPRT_CHG = 1
No
B_SRP_STARTED = 1
No
B_SRP_DONE = 1
No
B_SRP_TIMEOUT = 1
No
B_HNP_FAIL = 1
No
A_SRP_DETECT = 1
No
A_REQ_TIMEOUT = 1
No
A_VBUS_ERR = 1
No
DRIVER_SWITCH = 1
230 Universal Serial Bus (USB)
Yes
Non−blocking OTG
transceiver control
update
Yes
Inform the application that SRP has started. (The OMAP5912
OTG controller is acting as a default−B device.)
Yes
Inform the application that SRP has completed. (The
OMAP5912 OTG controller is acting as a default−B device.)
Inform the application that a default−A device did not respond
Yes
to the SRP request. The cable may not be properly
connected or the default−A device has a problem. (The
OMAP5912 OTG controller is acting as a default−B device.)
Yes
Inform the application that a HNP request has failed. (The
OMAP5912 OTG controller is acting as a default−B device.)
Set OTG_CTRL.A_BUSREQ to 1 and set
Yes
OTG_CTRL.BUSDROP to 0. Inform the application that a SRP
has been detected. Software should initialize the USB host
controller port and begin enumeration. (The OMAP5912 OTG
controller is acting as a default−A device.)
1. Set OTG_CTRL.A_BUSREQ to 0 and set OTG_CTRL.OTG_BUSDROP to 1.
Yes
Software should cancel enumeration and disable the USB host controller
port. Inform application that downstream device did not connect. Or,
2. Software could instead leave host controller active and wait for device
attach.
Set OTG_CTRL.A_BUSREQ to 0 and set
Yes
OTG_CTRL.OTG_BUSDROP to 1. Software should disable
the USB host port. Inform the application that VBUS power
Yes
OTG driver
switch
handler
Note − because I2C operations are slow relative to the MPU
instruction rate, I2C operations implemented within the OTG
interrupt handler would block other processor software. it is
recommended that the I2C update operation is not
implemented within the interrupt handler.
failed.
Write 1 to
OTG_IRQ_SRC.0
to clear the
interrupt source
Write 1 to
OTG_IRQ_SRC.7
to clear the
interrupt source
Write 1 to
OTG_IRQ_SRC.8
to clear the
interrupt source
Write 1 to
OTG_IRQ_SRC.9
to clear the
interrupt source
Write 1 to
OTG_IRQ_SRC.10
to clear the interrupt
source
Write 1 to
OTG_IRQ_SRC.11
to clear the interrupt
source
Write 1 to
OTG_IRQ_SRC.12
to clear the interrupt
source
Write 1 to
OTG_IRQ_SRC.13
to clear the interrupt
source
End of OTG interrupt handler
SPRU761A